- request_firmware() hotplug interface info.
floppy.txt
- notes and driver options for the floppy disk driver.
-fujitsu/
+frv/
- Fujitsu FR-V Linux documentation.
gpio.txt
- overview of GPIO (General Purpose Input/Output) access conventions.
--- /dev/null
+ ================================
+ Fujitsu FR-V LINUX DOCUMENTATION
+ ================================
+
+This directory contains documentation for the Fujitsu FR-V CPU architecture
+port of Linux.
+
+The following documents are available:
+
+ (*) features.txt
+
+ A description of the basic features inherent in this architecture port.
+
+
+ (*) configuring.txt
+
+ A summary of the configuration options particular to this architecture.
+
+
+ (*) booting.txt
+
+ A description of how to boot the kernel image and a summary of the kernel
+ command line options.
+
+
+ (*) gdbstub.txt
+
+ A description of how to debug the kernel using GDB attached by serial
+ port, and a summary of the services available.
+
+
+ (*) mmu-layout.txt
+
+ A description of the virtual and physical memory layout used in the
+ MMU linux kernel, and the registers used to support it.
+
+
+ (*) gdbinit
+
+ An example .gdbinit file for use with GDB. It includes macros for viewing
+ MMU state on the FR451. See mmu-layout.txt for more information.
+
+
+ (*) clock.txt
+
+ A description of the CPU clock scaling interface.
+
+
+ (*) atomic-ops.txt
+
+ A description of how the FR-V kernel's atomic operations work.
--- /dev/null
+ =====================================
+ FUJITSU FR-V KERNEL ATOMIC OPERATIONS
+ =====================================
+
+On the FR-V CPUs, there is only one atomic Read-Modify-Write operation: the SWAP/SWAPI
+instruction. Unfortunately, this alone can't be used to implement the following operations:
+
+ (*) Atomic add to memory
+
+ (*) Atomic subtract from memory
+
+ (*) Atomic bit modification (set, clear or invert)
+
+ (*) Atomic compare and exchange
+
+On such CPUs, the standard way of emulating such operations in uniprocessor mode is to disable
+interrupts, but on the FR-V CPUs, modifying the PSR takes a lot of clock cycles, and it has to be
+done twice. This means the CPU runs for a relatively long time with interrupts disabled,
+potentially having a great effect on interrupt latency.
+
+
+=============
+NEW ALGORITHM
+=============
+
+To get around this, the following algorithm has been implemented. It operates in a way similar to
+the LL/SC instruction pairs supported on a number of platforms.
+
+ (*) The CCCR.CC3 register is reserved within the kernel to act as an atomic modify abort flag.
+
+ (*) In the exception prologues run on kernel->kernel entry, CCCR.CC3 is set to 0 (Undefined
+ state).
+
+ (*) All atomic operations can then be broken down into the following algorithm:
+
+ (1) Set ICC3.Z to true and set CC3 to True (ORCC/CKEQ/ORCR).
+
+ (2) Load the value currently in the memory to be modified into a register.
+
+ (3) Make changes to the value.
+
+ (4) If CC3 is still True, simultaneously and atomically (by VLIW packing):
+
+ (a) Store the modified value back to memory.
+
+ (b) Set ICC3.Z to false (CORCC on GR29 is sufficient for this - GR29 holds the current
+ task pointer in the kernel, and so is guaranteed to be non-zero).
+
+ (5) If ICC3.Z is still true, go back to step (1).
+
+This works in a non-SMP environment because any interrupt or other exception that happens between
+steps (1) and (4) will set CC3 to the Undefined, thus aborting the store in (4a), and causing the
+condition in ICC3 to remain with the Z flag set, thus causing step (5) to loop back to step (1).
+
+
+This algorithm suffers from two problems:
+
+ (1) The condition CCCR.CC3 is cleared unconditionally by an exception, irrespective of whether or
+ not any changes were made to the target memory location during that exception.
+
+ (2) The branch from step (5) back to step (1) may have to happen more than once until the store
+ manages to take place. In theory, this loop could cycle forever because there are too many
+ interrupts coming in, but it's unlikely.
+
+
+=======
+EXAMPLE
+=======
+
+Taking an example from include/asm-frv/atomic.h:
+
+ static inline int atomic_add_return(int i, atomic_t *v)
+ {
+ unsigned long val;
+
+ asm("0: \n"
+
+It starts by setting ICC3.Z to true for later use, and also transforming that into CC3 being in the
+True state.
+
+ " orcc gr0,gr0,gr0,icc3 \n" <-- (1)
+ " ckeq icc3,cc7 \n" <-- (1)
+
+Then it does the load. Note that the final phase of step (1) is done at the same time as the
+load. The VLIW packing ensures they are done simultaneously. The ".p" on the load must not be
+removed without swapping the order of these two instructions.
+
+ " ld.p %M0,%1 \n" <-- (2)
+ " orcr cc7,cc7,cc3 \n" <-- (1)
+
+Then the proposed modification is generated. Note that the old value can be retained if required
+(such as in test_and_set_bit()).
+
+ " add%I2 %1,%2,%1 \n" <-- (3)
+
+Then it attempts to store the value back, contingent on no exception having cleared CC3 since it
+was set to True.
+
+ " cst.p %1,%M0 ,cc3,#1 \n" <-- (4a)
+
+It simultaneously records the success or failure of the store in ICC3.Z.
+
+ " corcc gr29,gr29,gr0 ,cc3,#1 \n" <-- (4b)
+
+Such that the branch can then be taken if the operation was aborted.
+
+ " beq icc3,#0,0b \n" <-- (5)
+ : "+U"(v->counter), "=&r"(val)
+ : "NPr"(i)
+ : "memory", "cc7", "cc3", "icc3"
+ );
+
+ return val;
+ }
+
+
+=============
+CONFIGURATION
+=============
+
+The atomic ops implementation can be made inline or out-of-line by changing the
+CONFIG_FRV_OUTOFLINE_ATOMIC_OPS configuration variable. Making it out-of-line has a number of
+advantages:
+
+ - The resulting kernel image may be smaller
+ - Debugging is easier as atomic ops can just be stepped over and they can be breakpointed
+
+Keeping it inline also has a number of advantages:
+
+ - The resulting kernel may be Faster
+ - no out-of-line function calls need to be made
+ - the compiler doesn't have half its registers clobbered by making a call
+
+The out-of-line implementations live in arch/frv/lib/atomic-ops.S.
--- /dev/null
+ =========================
+ BOOTING FR-V LINUX KERNEL
+ =========================
+
+======================
+PROVIDING A FILESYSTEM
+======================
+
+First of all, a root filesystem must be made available. This can be done in
+one of two ways:
+
+ (1) NFS Export
+
+ A filesystem should be constructed in a directory on an NFS server that
+ the target board can reach. This directory should then be NFS exported
+ such that the target board can read and write into it as root.
+
+ (2) Flash Filesystem (JFFS2 Recommended)
+
+ In this case, the image must be stored or built up on flash before it
+ can be used. A complete image can be built using the mkfs.jffs2 or
+ similar program and then downloaded and stored into flash by RedBoot.
+
+
+========================
+LOADING THE KERNEL IMAGE
+========================
+
+The kernel will need to be loaded into RAM by RedBoot (or by some alternative
+boot loader) before it can be run. The kernel image (arch/frv/boot/Image) may
+be loaded in one of three ways:
+
+ (1) Load from Flash
+
+ This is the simplest. RedBoot can store an image in the flash (see the
+ RedBoot documentation) and then load it back into RAM. RedBoot keeps
+ track of the load address, entry point and size, so the command to do
+ this is simply:
+
+ fis load linux
+
+ The image is then ready to be executed.
+
+ (2) Load by TFTP
+
+ The following command will download a raw binary kernel image from the
+ default server (as negotiated by BOOTP) and store it into RAM:
+
+ load -b 0x00100000 -r /tftpboot/image.bin
+
+ The image is then ready to be executed.
+
+ (3) Load by Y-Modem
+
+ The following command will download a raw binary kernel image across the
+ serial port that RedBoot is currently using:
+
+ load -m ymodem -b 0x00100000 -r zImage
+
+ The serial client (such as minicom) must then be told to transmit the
+ program by Y-Modem.
+
+ When finished, the image will then be ready to be executed.
+
+
+==================
+BOOTING THE KERNEL
+==================
+
+Boot the image with the following RedBoot command:
+
+ exec -c "<CMDLINE>" 0x00100000
+
+For example:
+
+ exec -c "console=ttySM0,115200 ip=:::::dhcp root=/dev/mtdblock2 rw"
+
+This will start the kernel running. Note that if the GDB-stub is compiled in,
+then the kernel will immediately wait for GDB to connect over serial before
+doing anything else. See the section on kernel debugging with GDB.
+
+The kernel command line <CMDLINE> tells the kernel where its console is and
+how to find its root filesystem. This is made up of the following components,
+separated by spaces:
+
+ (*) console=ttyS<x>[,<baud>[<parity>[<bits>[<flow>]]]]
+
+ This specifies that the system console should output through on-chip
+ serial port <x> (which can be "0" or "1").
+
+ <baud> is a standard baud rate between 1200 and 115200 (default 9600).
+
+ <parity> is a parity setting of "N", "O", "E", "M" or "S" for None, Odd,
+ Even, Mark or Space. "None" is the default.
+
+ <stop> is "7" or "8" for the number of bits per character. "8" is the
+ default.
+
+ <flow> is "r" to use flow control (XCTS on serial port 2 only). The
+ default is to not use flow control.
+
+ For example:
+
+ console=ttyS0,115200
+
+ To use the first on-chip serial port at baud rate 115200, no parity, 8
+ bits, and no flow control.
+
+ (*) root=/dev/<xxxx>
+
+ This specifies the device upon which the root filesystem resides. For
+ example:
+
+ /dev/nfs NFS root filesystem
+ /dev/mtdblock3 Fourth RedBoot partition on the System Flash
+
+ (*) rw
+
+ Start with the root filesystem mounted Read/Write.
+
+ The remaining components are all optional:
+
+ (*) ip=<ip>::::<host>:<iface>:<cfg>
+
+ Configure the network interface. If <cfg> is "off" then <ip> should
+ specify the IP address for the network device <iface>. <host> provide
+ the hostname for the device.
+
+ If <cfg> is "bootp" or "dhcp", then all of these parameters will be
+ discovered by consulting a BOOTP or DHCP server.
+
+ For example, the following might be used:
+
+ ip=192.168.73.12::::frv:eth0:off
+
+ This sets the IP address on the VDK motherboard RTL8029 ethernet chipset
+ (eth0) to be 192.168.73.12, and sets the board's hostname to be "frv".
+
+ (*) nfsroot=<server>:<dir>[,v<vers>]
+
+ This is mandatory if "root=/dev/nfs" is given as an option. It tells the
+ kernel the IP address of the NFS server providing its root filesystem,
+ and the pathname on that server of the filesystem.
+
+ The NFS version to use can also be specified. v2 and v3 are supported by
+ Linux.
+
+ For example:
+
+ nfsroot=192.168.73.1:/nfsroot-frv
+
+ (*) profile=1
+
+ Turns on the kernel profiler (accessible through /proc/profile).
+
+ (*) console=gdb0
+
+ This can be used as an alternative to the "console=ttyS..." listed
+ above. I tells the kernel to pass the console output to GDB if the
+ gdbstub is compiled in to the kernel.
+
+ If this is used, then the gdbstub passes the text to GDB, which then
+ simply dumps it to its standard output.
+
+ (*) mem=<xxx>M
+
+ Normally the kernel will work out how much SDRAM it has by reading the
+ SDRAM controller registers. That can be overridden with this
+ option. This allows the kernel to be told that it has <xxx> megabytes of
+ memory available.
+
+ (*) init=<prog> [<arg> [<arg> [<arg> ...]]]
+
+ This tells the kernel what program to run initially. By default this is
+ /sbin/init, but /sbin/sash or /bin/sh are common alternatives.
+
+ (*) vdc=...
+
+ This option configures the MB93493 companion chip visual display
+ driver. Please see Documentation/frv/mb93493/vdc.txt for more
+ information.
--- /dev/null
+Clock scaling
+-------------
+
+The kernel supports scaling of CLCK.CMODE, CLCK.CM and CLKC.P0 clock
+registers. If built with CONFIG_PM and CONFIG_SYSCTL options enabled, four
+extra files will appear in the directory /proc/sys/pm/. Reading these files
+will show:
+
+ p0 -- current value of the P0 bit in CLKC register.
+ cm -- current value of the CM bits in CLKC register.
+ cmode -- current value of the CMODE bits in CLKC register.
+
+On all boards, the 'p0' file should also be writable, and either '1' or '0'
+can be rewritten, to set or clear the CLKC_P0 bit respectively, hence
+controlling whether the resource bus rate clock is halved.
+
+The 'cm' file should also be available on all boards. '0' can be written to it
+to shift the board into High-Speed mode (normal), and '1' can be written to
+shift the board into Medium-Speed mode. Selecting Low-Speed mode is not
+supported by this interface, even though some CPUs do support it.
+
+On the boards with FR405 CPU (i.e. CB60 and CB70), the 'cmode' file is also
+writable, allowing the CPU core speed (and other clock speeds) to be
+controlled from userspace.
+
+
+Determining current and possible settings
+-----------------------------------------
+
+The current state and the available masks can be found in /proc/cpuinfo. For
+example, on the CB70:
+
+ # cat /proc/cpuinfo
+ CPU-Series: fr400
+ CPU-Core: fr405, gr0-31, BE, CCCR
+ CPU: mb93405
+ MMU: Prot
+ FP-Media: fr0-31, Media
+ System: mb93091-cb70, mb93090-mb00
+ PM-Controls: cmode=0xd31f, cm=0x3, p0=0x3, suspend=0x9
+ PM-Status: cmode=3, cm=0, p0=0
+ Clock-In: 50.00 MHz
+ Clock-Core: 300.00 MHz
+ Clock-SDRAM: 100.00 MHz
+ Clock-CBus: 100.00 MHz
+ Clock-Res: 50.00 MHz
+ Clock-Ext: 50.00 MHz
+ Clock-DSU: 25.00 MHz
+ BogoMips: 300.00
+
+And on the PDK, the PM lines look like the following:
+
+ PM-Controls: cm=0x3, p0=0x3, suspend=0x9
+ PM-Status: cmode=9, cm=0, p0=0
+
+The PM-Controls line, if present, will indicate which /proc/sys/pm files can
+be set to what values. The specification values are bitmasks; so, for example,
+"suspend=0x9" indicates that 0 and 3 can be written validly to
+/proc/sys/pm/suspend.
+
+The PM-Controls line will only be present if CONFIG_PM is configured to Y.
+
+The PM-Status line indicates which clock controls are set to which value. If
+the file can be read, then the suspend value must be 0, and so that's not
+included.
--- /dev/null
+ =======================================
+ FUJITSU FR-V LINUX KERNEL CONFIGURATION
+ =======================================
+
+=====================
+CONFIGURATION OPTIONS
+=====================
+
+The most important setting is in the "MMU support options" tab (the first
+presented in the configuration tools available):
+
+ (*) "Kernel Type"
+
+ This options allows selection of normal, MMU-requiring linux, and uClinux
+ (which doesn't require an MMU and doesn't have inter-process protection).
+
+There are a number of settings in the "Processor type and features" section of
+the kernel configuration that need to be considered.
+
+ (*) "CPU"
+
+ The register and instruction sets at the core of the processor. This can
+ only be set to "FR40x/45x/55x" at the moment - but this permits usage of
+ the kernel with MB93091 CB10, CB11, CB30, CB41, CB60, CB70 and CB451
+ CPU boards, and with the MB93093 PDK board.
+
+ (*) "System"
+
+ This option allows a choice of basic system. This governs the peripherals
+ that are expected to be available.
+
+ (*) "Motherboard"
+
+ This specifies the type of motherboard being used, and the peripherals
+ upon it. Currently only "MB93090-MB00" can be set here.
+
+ (*) "Default cache-write mode"
+
+ This controls the initial data cache write management mode. By default
+ Write-Through is selected, but Write-Back (Copy-Back) can also be
+ selected. This can be changed dynamically once the kernel is running (see
+ features.txt).
+
+There are some architecture specific configuration options in the "General
+Setup" section of the kernel configuration too:
+
+ (*) "Reserve memory uncached for (PCI) DMA"
+
+ This requests that a uClinux kernel set aside some memory in an uncached
+ window for the use as consistent DMA memory (mainly for PCI). At least a
+ megabyte will be allocated in this way, possibly more. Any memory so
+ reserved will not be available for normal allocations.
+
+ (*) "Kernel support for ELF-FDPIC binaries"
+
+ This enables the binary-format driver for the new FDPIC ELF binaries that
+ this platform normally uses. These binaries are totally relocatable -
+ their separate sections can relocated independently, allowing them to be
+ shared on uClinux where possible. This should normally be enabled.
+
+ (*) "Kernel image protection"
+
+ This makes the protection register governing access to the core kernel
+ image prohibit access by userspace programs. This option is available on
+ uClinux only.
+
+There are also a number of settings in the "Kernel Hacking" section of the
+kernel configuration especially for debugging a kernel on this
+architecture. See the "gdbstub.txt" file for information about those.
+
+
+======================
+DEFAULT CONFIGURATIONS
+======================
+
+The kernel sources include a number of example default configurations:
+
+ (*) defconfig-mb93091
+
+ Default configuration for the MB93091-VDK with both CPU board and
+ MB93090-MB00 motherboard running uClinux.
+
+
+ (*) defconfig-mb93091-fb
+
+ Default configuration for the MB93091-VDK with CPU board,
+ MB93090-MB00 motherboard, and DAV board running uClinux.
+ Includes framebuffer driver.
+
+
+ (*) defconfig-mb93093
+
+ Default configuration for the MB93093-PDK board running uClinux.
+
+
+ (*) defconfig-cb70-standalone
+
+ Default configuration for the MB93091-VDK with only CB70 CPU board
+ running uClinux. This will use the CB70's DM9000 for network access.
+
+
+ (*) defconfig-mmu
+
+ Default configuration for the MB93091-VDK with both CB451 CPU board and
+ MB93090-MB00 motherboard running MMU linux.
+
+ (*) defconfig-mmu-audio
+
+ Default configuration for the MB93091-VDK with CB451 CPU board, DAV
+ board, and MB93090-MB00 motherboard running MMU linux. Includes
+ audio driver.
+
+ (*) defconfig-mmu-fb
+
+ Default configuration for the MB93091-VDK with CB451 CPU board, DAV
+ board, and MB93090-MB00 motherboard running MMU linux. Includes
+ framebuffer driver.
+
+ (*) defconfig-mmu-standalone
+
+ Default configuration for the MB93091-VDK with only CB451 CPU board
+ running MMU linux.
+
+
+
--- /dev/null
+ ===========================
+ FUJITSU FR-V LINUX FEATURES
+ ===========================
+
+This kernel port has a number of features of which the user should be aware:
+
+ (*) Linux and uClinux
+
+ The FR-V architecture port supports both normal MMU linux and uClinux out
+ of the same sources.
+
+
+ (*) CPU support
+
+ Support for the FR401, FR403, FR405, FR451 and FR555 CPUs should work with
+ the same uClinux kernel configuration.
+
+ In normal (MMU) Linux mode, only the FR451 CPU will work as that is the
+ only one with a suitably featured CPU.
+
+ The kernel is written and compiled with the assumption that only the
+ bottom 32 GR registers and no FR registers will be used by the kernel
+ itself, however all extra userspace registers will be saved on context
+ switch. Note that since most CPUs can't support lazy switching, no attempt
+ is made to do lazy register saving where that would be possible (FR555
+ only currently).
+
+
+ (*) Board support
+
+ The board on which the kernel will run can be configured on the "Processor
+ type and features" configuration tab.
+
+ Set the System to "MB93093-PDK" to boot from the MB93093 (FR403) PDK.
+
+ Set the System to "MB93091-VDK" to boot from the CB11, CB30, CB41, CB60,
+ CB70 or CB451 VDK boards. Set the Motherboard setting to "MB93090-MB00" to
+ boot with the standard ATA90590B VDK motherboard, and set it to "None" to
+ boot without any motherboard.
+
+
+ (*) Binary Formats
+
+ The only userspace binary format supported is FDPIC ELF. Normal ELF, FLAT
+ and AOUT binaries are not supported for this architecture.
+
+ FDPIC ELF supports shared library and program interpreter facilities.
+
+
+ (*) Scheduler Speed
+
+ The kernel scheduler runs at 100Hz irrespective of the clock speed on this
+ architecture. This value is set in asm/param.h (see the HZ macro defined
+ there).
+
+
+ (*) Normal (MMU) Linux Memory Layout.
+
+ See mmu-layout.txt in this directory for a description of the normal linux
+ memory layout
+
+ See include/asm-frv/mem-layout.h for constants pertaining to the memory
+ layout.
+
+ See include/asm-frv/mb-regs.h for the constants pertaining to the I/O bus
+ controller configuration.
+
+
+ (*) uClinux Memory Layout
+
+ The memory layout used by the uClinux kernel is as follows:
+
+ 0x00000000 - 0x00000FFF Null pointer catch page
+ 0x20000000 - 0x200FFFFF CS2# [PDK] FPGA
+ 0xC0000000 - 0xCFFFFFFF SDRAM
+ 0xC0000000 Base of Linux kernel image
+ 0xE0000000 - 0xEFFFFFFF CS2# [VDK] SLBUS/PCI window
+ 0xF0000000 - 0xF0FFFFFF CS5# MB93493 CSC area (DAV daughter board)
+ 0xF1000000 - 0xF1FFFFFF CS7# [CB70/CB451] CPU-card PCMCIA port space
+ 0xFC000000 - 0xFC0FFFFF CS1# [VDK] MB86943 config space
+ 0xFC100000 - 0xFC1FFFFF CS6# [CB70/CB451] CPU-card DM9000 NIC space
+ 0xFC100000 - 0xFC1FFFFF CS6# [PDK] AX88796 NIC space
+ 0xFC200000 - 0xFC2FFFFF CS3# MB93493 CSR area (DAV daughter board)
+ 0xFD000000 - 0xFDFFFFFF CS4# [CB70/CB451] CPU-card extra flash space
+ 0xFE000000 - 0xFEFFFFFF Internal CPU peripherals
+ 0xFF000000 - 0xFF1FFFFF CS0# Flash 1
+ 0xFF200000 - 0xFF3FFFFF CS0# Flash 2
+ 0xFFC00000 - 0xFFC0001F CS0# [VDK] FPGA
+
+ The kernel reads the size of the SDRAM from the memory bus controller
+ registers by default.
+
+ The kernel initialisation code (1) adjusts the SDRAM base addresses to
+ move the SDRAM to desired address, (2) moves the kernel image down to the
+ bottom of SDRAM, (3) adjusts the bus controller registers to move I/O
+ windows, and (4) rearranges the protection registers to protect all of
+ this.
+
+ The reasons for doing this are: (1) the page at address 0 should be
+ inaccessible so that NULL pointer errors can be caught; and (2) the bottom
+ three quarters are left unoccupied so that an FR-V CPU with an MMU can use
+ it for virtual userspace mappings.
+
+ See include/asm-frv/mem-layout.h for constants pertaining to the memory
+ layout.
+
+ See include/asm-frv/mb-regs.h for the constants pertaining to the I/O bus
+ controller configuration.
+
+
+ (*) uClinux Memory Protection
+
+ A DAMPR register is used to cover the entire region used for I/O
+ (0xE0000000 - 0xFFFFFFFF). This permits the kernel to make uncached
+ accesses to this region. Userspace is not permitted to access it.
+
+ The DAMPR/IAMPR protection registers not in use for any other purpose are
+ tiled over the top of the SDRAM such that:
+
+ (1) The core kernel image is covered by as small a tile as possible
+ granting only the kernel access to the underlying data, whilst
+ making sure no SDRAM is actually made unavailable by this approach.
+
+ (2) All other tiles are arranged to permit userspace access to the rest
+ of the SDRAM.
+
+ Barring point (1), there is nothing to protect kernel data against
+ userspace damage - but this is uClinux.
+
+
+ (*) Exceptions and Fixups
+
+ Since the FR40x and FR55x CPUs that do not have full MMUs generate
+ imprecise data error exceptions, there are currently no automatic fixup
+ services available in uClinux. This includes misaligned memory access
+ fixups.
+
+ Userspace EFAULT errors can be trapped by issuing a MEMBAR instruction and
+ forcing the fault to happen there.
+
+ On the FR451, however, data exceptions are mostly precise, and so
+ exception fixup handling is implemented as normal.
+
+
+ (*) Userspace Breakpoints
+
+ The ptrace() system call supports the following userspace debugging
+ features:
+
+ (1) Hardware assisted single step.
+
+ (2) Breakpoint via the FR-V "BREAK" instruction.
+
+ (3) Breakpoint via the FR-V "TIRA GR0, #1" instruction.
+
+ (4) Syscall entry/exit trap.
+
+ Each of the above generates a SIGTRAP.
+
+
+ (*) On-Chip Serial Ports
+
+ The FR-V on-chip serial ports are made available as ttyS0 and ttyS1. Note
+ that if the GDB stub is compiled in, ttyS1 will not actually be available
+ as it will be being used for the GDB stub.
+
+ These ports can be made by:
+
+ mknod /dev/ttyS0 c 4 64
+ mknod /dev/ttyS1 c 4 65
+
+
+ (*) Maskable Interrupts
+
+ Level 15 (Non-maskable) interrupts are dealt with by the GDB stub if
+ present, and cause a panic if not. If the GDB stub is present, ttyS1's
+ interrupts are rated at level 15.
+
+ All other interrupts are distributed over the set of available priorities
+ so that no IRQs are shared where possible. The arch interrupt handling
+ routines attempt to disentangle the various sources available through the
+ CPU's own multiplexor, and those on off-CPU peripherals.
+
+
+ (*) Accessing PCI Devices
+
+ Where PCI is available, care must be taken when dealing with drivers that
+ access PCI devices. PCI devices present their data in little-endian form,
+ but the CPU sees it in big-endian form. The macros in asm/io.h try to get
+ this right, but may not under all circumstances...
+
+
+ (*) Ax88796 Ethernet Driver
+
+ The MB93093 PDK board has an Ax88796 ethernet chipset (an NE2000 clone). A
+ driver has been written to deal specifically with this. The driver
+ provides MII services for the card.
+
+ The driver can be configured by running make xconfig, and going to:
+
+ (*) Network device support
+ - turn on "Network device support"
+ (*) Ethernet (10 or 100Mbit)
+ - turn on "Ethernet (10 or 100Mbit)"
+ - turn on "AX88796 NE2000 compatible chipset"
+
+ The driver can be found in:
+
+ drivers/net/ax88796.c
+ include/asm/ax88796.h
+
+
+ (*) WorkRAM Driver
+
+ This driver provides a character device that permits access to the WorkRAM
+ that can be found on the FR451 CPU. Each page is accessible through a
+ separate minor number, thereby permitting each page to have its own
+ filesystem permissions set on the device file.
+
+ The device files should be:
+
+ mknod /dev/frv/workram0 c 240 0
+ mknod /dev/frv/workram1 c 240 1
+ mknod /dev/frv/workram2 c 240 2
+ ...
+
+ The driver will not permit the opening of any device file that does not
+ correspond to at least a partial page of WorkRAM. So the first device file
+ is the only one available on the FR451. If any other CPU is detected, none
+ of the devices will be openable.
+
+ The devices can be accessed with read, write and llseek, and can also be
+ mmapped. If they're mmapped, they will only map at the appropriate
+ 0x7e8nnnnn address on linux and at the 0xfe8nnnnn address on uClinux. If
+ MAP_FIXED is not specified, the appropriate address will be chosen anyway.
+
+ The mappings must be MAP_SHARED not MAP_PRIVATE, and must not be
+ PROT_EXEC. They must also start at file offset 0, and must not be longer
+ than one page in size.
+
+ This driver can be configured by running make xconfig, and going to:
+
+ (*) Character devices
+ - turn on "Fujitsu FR-V CPU WorkRAM support"
+
+
+ (*) Dynamic data cache write mode changing
+
+ It is possible to view and to change the data cache's write mode through
+ the /proc/sys/frv/cache-mode file while the kernel is running. There are
+ two modes available:
+
+ NAME MEANING
+ ===== ==========================================
+ wthru Data cache is in Write-Through mode
+ wback Data cache is in Write-Back/Copy-Back mode
+
+ To read the cache mode:
+
+ # cat /proc/sys/frv/cache-mode
+ wthru
+
+ To change the cache mode:
+
+ # echo wback >/proc/sys/frv/cache-mode
+ # cat /proc/sys/frv/cache-mode
+ wback
+
+
+ (*) MMU Context IDs and Pinning
+
+ On MMU Linux the CPU supports the concept of a context ID in its MMU to
+ make it more efficient (TLB entries are labelled with a context ID to link
+ them to specific tasks).
+
+ Normally once a context ID is allocated, it will remain affixed to a task
+ or CLONE_VM'd group of tasks for as long as it exists. However, since the
+ kernel is capable of supporting more tasks than there are possible ID
+ numbers, the kernel will pass context IDs from one task to another if
+ there are insufficient available.
+
+ The context ID currently in use by a task can be viewed in /proc:
+
+ # grep CXNR /proc/1/status
+ CXNR: 1
+
+ Note that kernel threads do not have a userspace context, and so will not
+ show a CXNR entry in that file.
+
+ Under some circumstances, however, it is desirable to pin a context ID on
+ a process such that the kernel won't pass it on. This can be done by
+ writing the process ID of the target process to a special file:
+
+ # echo 17 >/proc/sys/frv/pin-cxnr
+
+ Reading from the file will then show the context ID pinned.
+
+ # cat /proc/sys/frv/pin-cxnr
+ 4
+
+ The context ID will remain pinned as long as any process is using that
+ context, i.e.: when the all the subscribing processes have exited or
+ exec'd; or when an unpinning request happens:
+
+ # echo 0 >/proc/sys/frv/pin-cxnr
+
+ When there isn't a pinned context, the file shows -1:
+
+ # cat /proc/sys/frv/pin-cxnr
+ -1
--- /dev/null
+set remotebreak 1
+
+define _amr
+
+printf "AMRx DAMR IAMR \n"
+printf "==== ===================== =====================\n"
+printf "amr0 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x0].L,__debug_mmu.damr[0x0].P,__debug_mmu.iamr[0x0].L,__debug_mmu.iamr[0x0].P
+printf "amr1 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x1].L,__debug_mmu.damr[0x1].P,__debug_mmu.iamr[0x1].L,__debug_mmu.iamr[0x1].P
+printf "amr2 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x2].L,__debug_mmu.damr[0x2].P,__debug_mmu.iamr[0x2].L,__debug_mmu.iamr[0x2].P
+printf "amr3 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x3].L,__debug_mmu.damr[0x3].P,__debug_mmu.iamr[0x3].L,__debug_mmu.iamr[0x3].P
+printf "amr4 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x4].L,__debug_mmu.damr[0x4].P,__debug_mmu.iamr[0x4].L,__debug_mmu.iamr[0x4].P
+printf "amr5 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x5].L,__debug_mmu.damr[0x5].P,__debug_mmu.iamr[0x5].L,__debug_mmu.iamr[0x5].P
+printf "amr6 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x6].L,__debug_mmu.damr[0x6].P,__debug_mmu.iamr[0x6].L,__debug_mmu.iamr[0x6].P
+printf "amr7 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x7].L,__debug_mmu.damr[0x7].P,__debug_mmu.iamr[0x7].L,__debug_mmu.iamr[0x7].P
+
+printf "amr8 : L:%08lx P:%08lx\n",__debug_mmu.damr[0x8].L,__debug_mmu.damr[0x8].P
+printf "amr9 : L:%08lx P:%08lx\n",__debug_mmu.damr[0x9].L,__debug_mmu.damr[0x9].P
+printf "amr10: L:%08lx P:%08lx\n",__debug_mmu.damr[0xa].L,__debug_mmu.damr[0xa].P
+printf "amr11: L:%08lx P:%08lx\n",__debug_mmu.damr[0xb].L,__debug_mmu.damr[0xb].P
+
+end
+
+
+define _tlb
+printf "tlb[0x00]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x0].L,__debug_mmu.tlb[0x0].P,__debug_mmu.tlb[0x40+0x0].L,__debug_mmu.tlb[0x40+0x0].P
+printf "tlb[0x01]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1].L,__debug_mmu.tlb[0x1].P,__debug_mmu.tlb[0x40+0x1].L,__debug_mmu.tlb[0x40+0x1].P
+printf "tlb[0x02]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2].L,__debug_mmu.tlb[0x2].P,__debug_mmu.tlb[0x40+0x2].L,__debug_mmu.tlb[0x40+0x2].P
+printf "tlb[0x03]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3].L,__debug_mmu.tlb[0x3].P,__debug_mmu.tlb[0x40+0x3].L,__debug_mmu.tlb[0x40+0x3].P
+printf "tlb[0x04]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x4].L,__debug_mmu.tlb[0x4].P,__debug_mmu.tlb[0x40+0x4].L,__debug_mmu.tlb[0x40+0x4].P
+printf "tlb[0x05]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x5].L,__debug_mmu.tlb[0x5].P,__debug_mmu.tlb[0x40+0x5].L,__debug_mmu.tlb[0x40+0x5].P
+printf "tlb[0x06]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x6].L,__debug_mmu.tlb[0x6].P,__debug_mmu.tlb[0x40+0x6].L,__debug_mmu.tlb[0x40+0x6].P
+printf "tlb[0x07]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x7].L,__debug_mmu.tlb[0x7].P,__debug_mmu.tlb[0x40+0x7].L,__debug_mmu.tlb[0x40+0x7].P
+printf "tlb[0x08]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x8].L,__debug_mmu.tlb[0x8].P,__debug_mmu.tlb[0x40+0x8].L,__debug_mmu.tlb[0x40+0x8].P
+printf "tlb[0x09]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x9].L,__debug_mmu.tlb[0x9].P,__debug_mmu.tlb[0x40+0x9].L,__debug_mmu.tlb[0x40+0x9].P
+printf "tlb[0x0a]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xa].L,__debug_mmu.tlb[0xa].P,__debug_mmu.tlb[0x40+0xa].L,__debug_mmu.tlb[0x40+0xa].P
+printf "tlb[0x0b]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xb].L,__debug_mmu.tlb[0xb].P,__debug_mmu.tlb[0x40+0xb].L,__debug_mmu.tlb[0x40+0xb].P
+printf "tlb[0x0c]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xc].L,__debug_mmu.tlb[0xc].P,__debug_mmu.tlb[0x40+0xc].L,__debug_mmu.tlb[0x40+0xc].P
+printf "tlb[0x0d]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xd].L,__debug_mmu.tlb[0xd].P,__debug_mmu.tlb[0x40+0xd].L,__debug_mmu.tlb[0x40+0xd].P
+printf "tlb[0x0e]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xe].L,__debug_mmu.tlb[0xe].P,__debug_mmu.tlb[0x40+0xe].L,__debug_mmu.tlb[0x40+0xe].P
+printf "tlb[0x0f]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xf].L,__debug_mmu.tlb[0xf].P,__debug_mmu.tlb[0x40+0xf].L,__debug_mmu.tlb[0x40+0xf].P
+printf "tlb[0x10]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x10].L,__debug_mmu.tlb[0x10].P,__debug_mmu.tlb[0x40+0x10].L,__debug_mmu.tlb[0x40+0x10].P
+printf "tlb[0x11]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x11].L,__debug_mmu.tlb[0x11].P,__debug_mmu.tlb[0x40+0x11].L,__debug_mmu.tlb[0x40+0x11].P
+printf "tlb[0x12]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x12].L,__debug_mmu.tlb[0x12].P,__debug_mmu.tlb[0x40+0x12].L,__debug_mmu.tlb[0x40+0x12].P
+printf "tlb[0x13]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x13].L,__debug_mmu.tlb[0x13].P,__debug_mmu.tlb[0x40+0x13].L,__debug_mmu.tlb[0x40+0x13].P
+printf "tlb[0x14]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x14].L,__debug_mmu.tlb[0x14].P,__debug_mmu.tlb[0x40+0x14].L,__debug_mmu.tlb[0x40+0x14].P
+printf "tlb[0x15]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x15].L,__debug_mmu.tlb[0x15].P,__debug_mmu.tlb[0x40+0x15].L,__debug_mmu.tlb[0x40+0x15].P
+printf "tlb[0x16]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x16].L,__debug_mmu.tlb[0x16].P,__debug_mmu.tlb[0x40+0x16].L,__debug_mmu.tlb[0x40+0x16].P
+printf "tlb[0x17]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x17].L,__debug_mmu.tlb[0x17].P,__debug_mmu.tlb[0x40+0x17].L,__debug_mmu.tlb[0x40+0x17].P
+printf "tlb[0x18]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x18].L,__debug_mmu.tlb[0x18].P,__debug_mmu.tlb[0x40+0x18].L,__debug_mmu.tlb[0x40+0x18].P
+printf "tlb[0x19]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x19].L,__debug_mmu.tlb[0x19].P,__debug_mmu.tlb[0x40+0x19].L,__debug_mmu.tlb[0x40+0x19].P
+printf "tlb[0x1a]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1a].L,__debug_mmu.tlb[0x1a].P,__debug_mmu.tlb[0x40+0x1a].L,__debug_mmu.tlb[0x40+0x1a].P
+printf "tlb[0x1b]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1b].L,__debug_mmu.tlb[0x1b].P,__debug_mmu.tlb[0x40+0x1b].L,__debug_mmu.tlb[0x40+0x1b].P
+printf "tlb[0x1c]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1c].L,__debug_mmu.tlb[0x1c].P,__debug_mmu.tlb[0x40+0x1c].L,__debug_mmu.tlb[0x40+0x1c].P
+printf "tlb[0x1d]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1d].L,__debug_mmu.tlb[0x1d].P,__debug_mmu.tlb[0x40+0x1d].L,__debug_mmu.tlb[0x40+0x1d].P
+printf "tlb[0x1e]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1e].L,__debug_mmu.tlb[0x1e].P,__debug_mmu.tlb[0x40+0x1e].L,__debug_mmu.tlb[0x40+0x1e].P
+printf "tlb[0x1f]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1f].L,__debug_mmu.tlb[0x1f].P,__debug_mmu.tlb[0x40+0x1f].L,__debug_mmu.tlb[0x40+0x1f].P
+printf "tlb[0x20]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x20].L,__debug_mmu.tlb[0x20].P,__debug_mmu.tlb[0x40+0x20].L,__debug_mmu.tlb[0x40+0x20].P
+printf "tlb[0x21]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x21].L,__debug_mmu.tlb[0x21].P,__debug_mmu.tlb[0x40+0x21].L,__debug_mmu.tlb[0x40+0x21].P
+printf "tlb[0x22]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x22].L,__debug_mmu.tlb[0x22].P,__debug_mmu.tlb[0x40+0x22].L,__debug_mmu.tlb[0x40+0x22].P
+printf "tlb[0x23]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x23].L,__debug_mmu.tlb[0x23].P,__debug_mmu.tlb[0x40+0x23].L,__debug_mmu.tlb[0x40+0x23].P
+printf "tlb[0x24]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x24].L,__debug_mmu.tlb[0x24].P,__debug_mmu.tlb[0x40+0x24].L,__debug_mmu.tlb[0x40+0x24].P
+printf "tlb[0x25]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x25].L,__debug_mmu.tlb[0x25].P,__debug_mmu.tlb[0x40+0x25].L,__debug_mmu.tlb[0x40+0x25].P
+printf "tlb[0x26]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x26].L,__debug_mmu.tlb[0x26].P,__debug_mmu.tlb[0x40+0x26].L,__debug_mmu.tlb[0x40+0x26].P
+printf "tlb[0x27]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x27].L,__debug_mmu.tlb[0x27].P,__debug_mmu.tlb[0x40+0x27].L,__debug_mmu.tlb[0x40+0x27].P
+printf "tlb[0x28]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x28].L,__debug_mmu.tlb[0x28].P,__debug_mmu.tlb[0x40+0x28].L,__debug_mmu.tlb[0x40+0x28].P
+printf "tlb[0x29]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x29].L,__debug_mmu.tlb[0x29].P,__debug_mmu.tlb[0x40+0x29].L,__debug_mmu.tlb[0x40+0x29].P
+printf "tlb[0x2a]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2a].L,__debug_mmu.tlb[0x2a].P,__debug_mmu.tlb[0x40+0x2a].L,__debug_mmu.tlb[0x40+0x2a].P
+printf "tlb[0x2b]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2b].L,__debug_mmu.tlb[0x2b].P,__debug_mmu.tlb[0x40+0x2b].L,__debug_mmu.tlb[0x40+0x2b].P
+printf "tlb[0x2c]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2c].L,__debug_mmu.tlb[0x2c].P,__debug_mmu.tlb[0x40+0x2c].L,__debug_mmu.tlb[0x40+0x2c].P
+printf "tlb[0x2d]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2d].L,__debug_mmu.tlb[0x2d].P,__debug_mmu.tlb[0x40+0x2d].L,__debug_mmu.tlb[0x40+0x2d].P
+printf "tlb[0x2e]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2e].L,__debug_mmu.tlb[0x2e].P,__debug_mmu.tlb[0x40+0x2e].L,__debug_mmu.tlb[0x40+0x2e].P
+printf "tlb[0x2f]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2f].L,__debug_mmu.tlb[0x2f].P,__debug_mmu.tlb[0x40+0x2f].L,__debug_mmu.tlb[0x40+0x2f].P
+printf "tlb[0x30]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x30].L,__debug_mmu.tlb[0x30].P,__debug_mmu.tlb[0x40+0x30].L,__debug_mmu.tlb[0x40+0x30].P
+printf "tlb[0x31]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x31].L,__debug_mmu.tlb[0x31].P,__debug_mmu.tlb[0x40+0x31].L,__debug_mmu.tlb[0x40+0x31].P
+printf "tlb[0x32]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x32].L,__debug_mmu.tlb[0x32].P,__debug_mmu.tlb[0x40+0x32].L,__debug_mmu.tlb[0x40+0x32].P
+printf "tlb[0x33]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x33].L,__debug_mmu.tlb[0x33].P,__debug_mmu.tlb[0x40+0x33].L,__debug_mmu.tlb[0x40+0x33].P
+printf "tlb[0x34]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x34].L,__debug_mmu.tlb[0x34].P,__debug_mmu.tlb[0x40+0x34].L,__debug_mmu.tlb[0x40+0x34].P
+printf "tlb[0x35]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x35].L,__debug_mmu.tlb[0x35].P,__debug_mmu.tlb[0x40+0x35].L,__debug_mmu.tlb[0x40+0x35].P
+printf "tlb[0x36]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x36].L,__debug_mmu.tlb[0x36].P,__debug_mmu.tlb[0x40+0x36].L,__debug_mmu.tlb[0x40+0x36].P
+printf "tlb[0x37]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x37].L,__debug_mmu.tlb[0x37].P,__debug_mmu.tlb[0x40+0x37].L,__debug_mmu.tlb[0x40+0x37].P
+printf "tlb[0x38]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x38].L,__debug_mmu.tlb[0x38].P,__debug_mmu.tlb[0x40+0x38].L,__debug_mmu.tlb[0x40+0x38].P
+printf "tlb[0x39]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x39].L,__debug_mmu.tlb[0x39].P,__debug_mmu.tlb[0x40+0x39].L,__debug_mmu.tlb[0x40+0x39].P
+printf "tlb[0x3a]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3a].L,__debug_mmu.tlb[0x3a].P,__debug_mmu.tlb[0x40+0x3a].L,__debug_mmu.tlb[0x40+0x3a].P
+printf "tlb[0x3b]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3b].L,__debug_mmu.tlb[0x3b].P,__debug_mmu.tlb[0x40+0x3b].L,__debug_mmu.tlb[0x40+0x3b].P
+printf "tlb[0x3c]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3c].L,__debug_mmu.tlb[0x3c].P,__debug_mmu.tlb[0x40+0x3c].L,__debug_mmu.tlb[0x40+0x3c].P
+printf "tlb[0x3d]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3d].L,__debug_mmu.tlb[0x3d].P,__debug_mmu.tlb[0x40+0x3d].L,__debug_mmu.tlb[0x40+0x3d].P
+printf "tlb[0x3e]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3e].L,__debug_mmu.tlb[0x3e].P,__debug_mmu.tlb[0x40+0x3e].L,__debug_mmu.tlb[0x40+0x3e].P
+printf "tlb[0x3f]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3f].L,__debug_mmu.tlb[0x3f].P,__debug_mmu.tlb[0x40+0x3f].L,__debug_mmu.tlb[0x40+0x3f].P
+end
+
+
+define _pgd
+p (pgd_t[0x40])*(pgd_t*)(__debug_mmu.damr[0x3].L)
+end
+
+define _ptd_i
+p (pte_t[0x1000])*(pte_t*)(__debug_mmu.damr[0x4].L)
+end
+
+define _ptd_d
+p (pte_t[0x1000])*(pte_t*)(__debug_mmu.damr[0x5].L)
+end
--- /dev/null
+ ====================
+ DEBUGGING FR-V LINUX
+ ====================
+
+
+The kernel contains a GDB stub that talks GDB remote protocol across a serial
+port. This permits GDB to single step through the kernel, set breakpoints and
+trap exceptions that happen in kernel space and interrupt execution. It also
+permits the NMI interrupt button or serial port events to jump the kernel into
+the debugger.
+
+On the CPUs that have on-chip UARTs (FR400, FR403, FR405, FR555), the
+GDB stub hijacks a serial port for its own purposes, and makes it
+generate level 15 interrupts (NMI). The kernel proper cannot see the serial
+port in question under these conditions.
+
+On the MB93091-VDK CPU boards, the GDB stub uses UART1, which would otherwise
+be /dev/ttyS1. On the MB93093-PDK, the GDB stub uses UART0. Therefore, on the
+PDK there is no externally accessible serial port and the serial port to
+which the touch screen is attached becomes /dev/ttyS0.
+
+Note that the GDB stub runs entirely within CPU debug mode, and so should not
+incur any exceptions or interrupts whilst it is active. In particular, note
+that the clock will lose time since it is implemented in software.
+
+
+==================
+KERNEL PREPARATION
+==================
+
+Firstly, a debuggable kernel must be built. To do this, unpack the kernel tree
+and copy the configuration that you wish to use to .config. Then reconfigure
+the following things on the "Kernel Hacking" tab:
+
+ (*) "Include debugging information"
+
+ Set this to "Y". This causes all C and Assembly files to be compiled
+ to include debugging information.
+
+ (*) "In-kernel GDB stub"
+
+ Set this to "Y". This causes the GDB stub to be compiled into the
+ kernel.
+
+ (*) "Immediate activation"
+
+ Set this to "Y" if you want the GDB stub to activate as soon as possible
+ and wait for GDB to connect. This allows you to start tracing right from
+ the beginning of start_kernel() in init/main.c.
+
+ (*) "Console through GDB stub"
+
+ Set this to "Y" if you wish to be able to use "console=gdb0" on the
+ command line. That tells the kernel to pass system console messages to
+ GDB (which then prints them on its standard output). This is useful when
+ debugging the serial drivers that'd otherwise be used to pass console
+ messages to the outside world.
+
+Then build as usual, download to the board and execute. Note that if
+"Immediate activation" was selected, then the kernel will wait for GDB to
+attach. If not, then the kernel will boot immediately and GDB will have to
+interrupt it or wait for an exception to occur before doing anything with
+the kernel.
+
+
+=========================
+KERNEL DEBUGGING WITH GDB
+=========================
+
+Set the serial port on the computer that's going to run GDB to the appropriate
+baud rate. Assuming the board's debug port is connected to ttyS0/COM1 on the
+computer doing the debugging:
+
+ stty -F /dev/ttyS0 115200
+
+Then start GDB in the base of the kernel tree:
+
+ frv-uclinux-gdb linux [uClinux]
+
+Or:
+
+ frv-uclinux-gdb vmlinux [MMU linux]
+
+When the prompt appears:
+
+ GNU gdb frv-031024
+ Copyright 2003 Free Software Foundation, Inc.
+ GDB is free software, covered by the GNU General Public License, and you are
+ welcome to change it and/or distribute copies of it under certain conditions.
+ Type "show copying" to see the conditions.
+ There is absolutely no warranty for GDB. Type "show warranty" for details.
+ This GDB was configured as "--host=i686-pc-linux-gnu --target=frv-uclinux"...
+ (gdb)
+
+Attach to the board like this:
+
+ (gdb) target remote /dev/ttyS0
+ Remote debugging using /dev/ttyS0
+ start_kernel () at init/main.c:395
+ (gdb)
+
+This should show the appropriate lines from the source too. The kernel can
+then be debugged almost as if it's any other program.
+
+
+===============================
+INTERRUPTING THE RUNNING KERNEL
+===============================
+
+The kernel can be interrupted whilst it is running, causing a jump back to the
+GDB stub and the debugger:
+
+ (*) Pressing Ctrl-C in GDB. This will cause GDB to try and interrupt the
+ kernel by sending an RS232 BREAK over the serial line to the GDB
+ stub. This will (mostly) immediately interrupt the kernel and return it
+ to the debugger.
+
+ (*) Pressing the NMI button on the board will also cause a jump into the
+ debugger.
+
+ (*) Setting a software breakpoint. This sets a break instruction at the
+ desired location which the GDB stub then traps the exception for.
+
+ (*) Setting a hardware breakpoint. The GDB stub is capable of using the IBAR
+ and DBAR registers to assist debugging.
+
+Furthermore, the GDB stub will intercept a number of exceptions automatically
+if they are caused by kernel execution. It will also intercept BUG() macro
+invocation.
+
--- /dev/null
+ =================================
+ INTERNAL KERNEL ABI FOR FR-V ARCH
+ =================================
+
+The internal FRV kernel ABI is not quite the same as the userspace ABI. A
+number of the registers are used for special purposed, and the ABI is not
+consistent between modules vs core, and MMU vs no-MMU.
+
+This partly stems from the fact that FRV CPUs do not have a separate
+supervisor stack pointer, and most of them do not have any scratch
+registers, thus requiring at least one general purpose register to be
+clobbered in such an event. Also, within the kernel core, it is possible to
+simply jump or call directly between functions using a relative offset.
+This cannot be extended to modules for the displacement is likely to be too
+far. Thus in modules the address of a function to call must be calculated
+in a register and then used, requiring two extra instructions.
+
+This document has the following sections:
+
+ (*) System call register ABI
+ (*) CPU operating modes
+ (*) Internal kernel-mode register ABI
+ (*) Internal debug-mode register ABI
+ (*) Virtual interrupt handling
+
+
+========================
+SYSTEM CALL REGISTER ABI
+========================
+
+When a system call is made, the following registers are effective:
+
+ REGISTERS CALL RETURN
+ =============== ======================= =======================
+ GR7 System call number Preserved
+ GR8 Syscall arg #1 Return value
+ GR9-GR13 Syscall arg #2-6 Preserved
+
+
+===================
+CPU OPERATING MODES
+===================
+
+The FR-V CPU has three basic operating modes. In order of increasing
+capability:
+
+ (1) User mode.
+
+ Basic userspace running mode.
+
+ (2) Kernel mode.
+
+ Normal kernel mode. There are many additional control registers
+ available that may be accessed in this mode, in addition to all the
+ stuff available to user mode. This has two submodes:
+
+ (a) Exceptions enabled (PSR.T == 1).
+
+ Exceptions will invoke the appropriate normal kernel mode
+ handler. On entry to the handler, the PSR.T bit will be cleared.
+
+ (b) Exceptions disabled (PSR.T == 0).
+
+ No exceptions or interrupts may happen. Any mandatory exceptions
+ will cause the CPU to halt unless the CPU is told to jump into
+ debug mode instead.
+
+ (3) Debug mode.
+
+ No exceptions may happen in this mode. Memory protection and
+ management exceptions will be flagged for later consideration, but
+ the exception handler won't be invoked. Debugging traps such as
+ hardware breakpoints and watchpoints will be ignored. This mode is
+ entered only by debugging events obtained from the other two modes.
+
+ All kernel mode registers may be accessed, plus a few extra debugging
+ specific registers.
+
+
+=================================
+INTERNAL KERNEL-MODE REGISTER ABI
+=================================
+
+There are a number of permanent register assignments that are set up by
+entry.S in the exception prologue. Note that there is a complete set of
+exception prologues for each of user->kernel transition and kernel->kernel
+transition. There are also user->debug and kernel->debug mode transition
+prologues.
+
+
+ REGISTER FLAVOUR USE
+ =============== ======= ==============================================
+ GR1 Supervisor stack pointer
+ GR15 Current thread info pointer
+ GR16 GP-Rel base register for small data
+ GR28 Current exception frame pointer (__frame)
+ GR29 Current task pointer (current)
+ GR30 Destroyed by kernel mode entry
+ GR31 NOMMU Destroyed by debug mode entry
+ GR31 MMU Destroyed by TLB miss kernel mode entry
+ CCR.ICC2 Virtual interrupt disablement tracking
+ CCCR.CC3 Cleared by exception prologue
+ (atomic op emulation)
+ SCR0 MMU See mmu-layout.txt.
+ SCR1 MMU See mmu-layout.txt.
+ SCR2 MMU Save for EAR0 (destroyed by icache insns
+ in debug mode)
+ SCR3 MMU Save for GR31 during debug exceptions
+ DAMR/IAMR NOMMU Fixed memory protection layout.
+ DAMR/IAMR MMU See mmu-layout.txt.
+
+
+Certain registers are also used or modified across function calls:
+
+ REGISTER CALL RETURN
+ =============== =============================== ======================
+ GR0 Fixed Zero -
+ GR2 Function call frame pointer
+ GR3 Special Preserved
+ GR3-GR7 - Clobbered
+ GR8 Function call arg #1 Return value
+ (or clobbered)
+ GR9 Function call arg #2 Return value MSW
+ (or clobbered)
+ GR10-GR13 Function call arg #3-#6 Clobbered
+ GR14 - Clobbered
+ GR15-GR16 Special Preserved
+ GR17-GR27 - Preserved
+ GR28-GR31 Special Only accessed
+ explicitly
+ LR Return address after CALL Clobbered
+ CCR/CCCR - Mostly Clobbered
+
+
+================================
+INTERNAL DEBUG-MODE REGISTER ABI
+================================
+
+This is the same as the kernel-mode register ABI for functions calls. The
+difference is that in debug-mode there's a different stack and a different
+exception frame. Almost all the global registers from kernel-mode
+(including the stack pointer) may be changed.
+
+ REGISTER FLAVOUR USE
+ =============== ======= ==============================================
+ GR1 Debug stack pointer
+ GR16 GP-Rel base register for small data
+ GR31 Current debug exception frame pointer
+ (__debug_frame)
+ SCR3 MMU Saved value of GR31
+
+
+Note that debug mode is able to interfere with the kernel's emulated atomic
+ops, so it must be exceedingly careful not to do any that would interact
+with the main kernel in this regard. Hence the debug mode code (gdbstub) is
+almost completely self-contained. The only external code used is the
+sprintf family of functions.
+
+Furthermore, break.S is so complicated because single-step mode does not
+switch off on entry to an exception. That means unless manually disabled,
+single-stepping will blithely go on stepping into things like interrupts.
+See gdbstub.txt for more information.
+
+
+==========================
+VIRTUAL INTERRUPT HANDLING
+==========================
+
+Because accesses to the PSR is so slow, and to disable interrupts we have
+to access it twice (once to read and once to write), we don't actually
+disable interrupts at all if we don't have to. What we do instead is use
+the ICC2 condition code flags to note virtual disablement, such that if we
+then do take an interrupt, we note the flag, really disable interrupts, set
+another flag and resume execution at the point the interrupt happened.
+Setting condition flags as a side effect of an arithmetic or logical
+instruction is really fast. This use of the ICC2 only occurs within the
+kernel - it does not affect userspace.
+
+The flags we use are:
+
+ (*) CCR.ICC2.Z [Zero flag]
+
+ Set to virtually disable interrupts, clear when interrupts are
+ virtually enabled. Can be modified by logical instructions without
+ affecting the Carry flag.
+
+ (*) CCR.ICC2.C [Carry flag]
+
+ Clear to indicate hardware interrupts are really disabled, set otherwise.
+
+
+What happens is this:
+
+ (1) Normal kernel-mode operation.
+
+ ICC2.Z is 0, ICC2.C is 1.
+
+ (2) An interrupt occurs. The exception prologue examines ICC2.Z and
+ determines that nothing needs doing. This is done simply with an
+ unlikely BEQ instruction.
+
+ (3) The interrupts are disabled (local_irq_disable)
+
+ ICC2.Z is set to 1.
+
+ (4) If interrupts were then re-enabled (local_irq_enable):
+
+ ICC2.Z would be set to 0.
+
+ A TIHI #2 instruction (trap #2 if condition HI - Z==0 && C==0) would
+ be used to trap if interrupts were now virtually enabled, but
+ physically disabled - which they're not, so the trap isn't taken. The
+ kernel would then be back to state (1).
+
+ (5) An interrupt occurs. The exception prologue examines ICC2.Z and
+ determines that the interrupt shouldn't actually have happened. It
+ jumps aside, and there disabled interrupts by setting PSR.PIL to 14
+ and then it clears ICC2.C.
+
+ (6) If interrupts were then saved and disabled again (local_irq_save):
+
+ ICC2.Z would be shifted into the save variable and masked off
+ (giving a 1).
+
+ ICC2.Z would then be set to 1 (thus unchanged), and ICC2.C would be
+ unaffected (ie: 0).
+
+ (7) If interrupts were then restored from state (6) (local_irq_restore):
+
+ ICC2.Z would be set to indicate the result of XOR'ing the saved
+ value (ie: 1) with 1, which gives a result of 0 - thus leaving
+ ICC2.Z set.
+
+ ICC2.C would remain unaffected (ie: 0).
+
+ A TIHI #2 instruction would be used to again assay the current state,
+ but this would do nothing as Z==1.
+
+ (8) If interrupts were then enabled (local_irq_enable):
+
+ ICC2.Z would be cleared. ICC2.C would be left unaffected. Both
+ flags would now be 0.
+
+ A TIHI #2 instruction again issued to assay the current state would
+ then trap as both Z==0 [interrupts virtually enabled] and C==0
+ [interrupts really disabled] would then be true.
+
+ (9) The trap #2 handler would simply enable hardware interrupts
+ (set PSR.PIL to 0), set ICC2.C to 1 and return.
+
+(10) Immediately upon returning, the pending interrupt would be taken.
+
+(11) The interrupt handler would take the path of actually processing the
+ interrupt (ICC2.Z is clear, BEQ fails as per step (2)).
+
+(12) The interrupt handler would then set ICC2.C to 1 since hardware
+ interrupts are definitely enabled - or else the kernel wouldn't be here.
+
+(13) On return from the interrupt handler, things would be back to state (1).
+
+This trap (#2) is only available in kernel mode. In user mode it will
+result in SIGILL.
--- /dev/null
+ =================================
+ FR451 MMU LINUX MEMORY MANAGEMENT
+ =================================
+
+============
+MMU HARDWARE
+============
+
+FR451 MMU Linux puts the MMU into EDAT mode whilst running. This means that it uses both the SAT
+registers and the DAT TLB to perform address translation.
+
+There are 8 IAMLR/IAMPR register pairs and 16 DAMLR/DAMPR register pairs for SAT mode.
+
+In DAT mode, there is also a TLB organised in cache format as 64 lines x 2 ways. Each line spans a
+16KB range of addresses, but can match a larger region.
+
+
+===========================
+MEMORY MANAGEMENT REGISTERS
+===========================
+
+Certain control registers are used by the kernel memory management routines:
+
+ REGISTERS USAGE
+ ====================== ==================================================
+ IAMR0, DAMR0 Kernel image and data mappings
+ IAMR1, DAMR1 First-chance TLB lookup mapping
+ DAMR2 Page attachment for cache flush by page
+ DAMR3 Current PGD mapping
+ SCR0, DAMR4 Instruction TLB PGE/PTD cache
+ SCR1, DAMR5 Data TLB PGE/PTD cache
+ DAMR6-10 kmap_atomic() mappings
+ DAMR11 I/O mapping
+ CXNR mm_struct context ID
+ TTBR Page directory (PGD) pointer (physical address)
+
+
+=====================
+GENERAL MEMORY LAYOUT
+=====================
+
+The physical memory layout is as follows:
+
+ PHYSICAL ADDRESS CONTROLLER DEVICE
+ =================== ============== =======================================
+ 00000000 - BFFFFFFF SDRAM SDRAM area
+ E0000000 - EFFFFFFF L-BUS CS2# VDK SLBUS/PCI window
+ F0000000 - F0FFFFFF L-BUS CS5# MB93493 CSC area (DAV daughter board)
+ F1000000 - F1FFFFFF L-BUS CS7# (CB70 CPU-card PCMCIA port I/O space)
+ FC000000 - FC0FFFFF L-BUS CS1# VDK MB86943 config space
+ FC100000 - FC1FFFFF L-BUS CS6# DM9000 NIC I/O space
+ FC200000 - FC2FFFFF L-BUS CS3# MB93493 CSR area (DAV daughter board)
+ FD000000 - FDFFFFFF L-BUS CS4# (CB70 CPU-card extra flash space)
+ FE000000 - FEFFFFFF Internal CPU peripherals
+ FF000000 - FF1FFFFF L-BUS CS0# Flash 1
+ FF200000 - FF3FFFFF L-BUS CS0# Flash 2
+ FFC00000 - FFC0001F L-BUS CS0# FPGA
+
+The virtual memory layout is:
+
+ VIRTUAL ADDRESS PHYSICAL TRANSLATOR FLAGS SIZE OCCUPATION
+ ================= ======== ============== ======= ======= ===================================
+ 00004000-BFFFFFFF various TLB,xAMR1 D-N-??V 3GB Userspace
+ C0000000-CFFFFFFF 00000000 xAMPR0 -L-S--V 256MB Kernel image and data
+ D0000000-D7FFFFFF various TLB,xAMR1 D-NS??V 128MB vmalloc area
+ D8000000-DBFFFFFF various TLB,xAMR1 D-NS??V 64MB kmap() area
+ DC000000-DCFFFFFF various TLB 1MB Secondary kmap_atomic() frame
+ DD000000-DD27FFFF various DAMR 160KB Primary kmap_atomic() frame
+ DD040000 DAMR2/IAMR2 -L-S--V page Page cache flush attachment point
+ DD080000 DAMR3 -L-SC-V page Page Directory (PGD)
+ DD0C0000 DAMR4 -L-SC-V page Cached insn TLB Page Table lookup
+ DD100000 DAMR5 -L-SC-V page Cached data TLB Page Table lookup
+ DD140000 DAMR6 -L-S--V page kmap_atomic(KM_BOUNCE_READ)
+ DD180000 DAMR7 -L-S--V page kmap_atomic(KM_SKB_SUNRPC_DATA)
+ DD1C0000 DAMR8 -L-S--V page kmap_atomic(KM_SKB_DATA_SOFTIRQ)
+ DD200000 DAMR9 -L-S--V page kmap_atomic(KM_USER0)
+ DD240000 DAMR10 -L-S--V page kmap_atomic(KM_USER1)
+ E0000000-FFFFFFFF E0000000 DAMR11 -L-SC-V 512MB I/O region
+
+IAMPR1 and DAMPR1 are used as an extension to the TLB.
+
+
+====================
+KMAP AND KMAP_ATOMIC
+====================
+
+To access pages in the page cache (which may not be directly accessible if highmem is available),
+the kernel calls kmap(), does the access and then calls kunmap(); or it calls kmap_atomic(), does
+the access and then calls kunmap_atomic().
+
+kmap() creates an attachment between an arbitrary inaccessible page and a range of virtual
+addresses by installing a PTE in a special page table. The kernel can then access this page as it
+wills. When it's finished, the kernel calls kunmap() to clear the PTE.
+
+kmap_atomic() does something slightly different. In the interests of speed, it chooses one of two
+strategies:
+
+ (1) If possible, kmap_atomic() attaches the requested page to one of DAMPR5 through DAMPR10
+ register pairs; and the matching kunmap_atomic() clears the DAMPR. This makes high memory
+ support really fast as there's no need to flush the TLB or modify the page tables. The DAMLR
+ registers being used for this are preset during boot and don't change over the lifetime of the
+ process. There's a direct mapping between the first few kmap_atomic() types, DAMR number and
+ virtual address slot.
+
+ However, there are more kmap_atomic() types defined than there are DAMR registers available,
+ so we fall back to:
+
+ (2) kmap_atomic() uses a slot in the secondary frame (determined by the type parameter), and then
+ locks an entry in the TLB to translate that slot to the specified page. The number of slots is
+ obviously limited, and their positions are controlled such that each slot is matched by a
+ different line in the TLB. kunmap() ejects the entry from the TLB.
+
+Note that the first three kmap atomic types are really just declared as placeholders. The DAMPR
+registers involved are actually modified directly.
+
+Also note that kmap() itself may sleep, kmap_atomic() may never sleep and both always succeed;
+furthermore, a driver using kmap() may sleep before calling kunmap(), but may not sleep before
+calling kunmap_atomic() if it had previously called kmap_atomic().
+
+
+===============================
+USING MORE THAN 256MB OF MEMORY
+===============================
+
+The kernel cannot access more than 256MB of memory directly. The physical layout, however, permits
+up to 3GB of SDRAM (possibly 3.25GB) to be made available. By using CONFIG_HIGHMEM, the kernel can
+allow userspace (by way of page tables) and itself (by way of kmap) to deal with the memory
+allocation.
+
+External devices can, of course, still DMA to and from all of the SDRAM, even if the kernel can't
+see it directly. The kernel translates page references into real addresses for communicating to the
+devices.
+
+
+===================
+PAGE TABLE TOPOLOGY
+===================
+
+The page tables are arranged in 2-layer format. There is a middle layer (PMD) that would be used in
+3-layer format tables but that is folded into the top layer (PGD) and so consumes no extra memory
+or processing power.
+
+ +------+ PGD PMD
+ | TTBR |--->+-------------------+
+ +------+ | | : STE |
+ | PGE0 | PME0 : STE |
+ | | : STE |
+ +-------------------+ Page Table
+ | | : STE -------------->+--------+ +0x0000
+ | PGE1 | PME0 : STE -----------+ | PTE0 |
+ | | : STE -------+ | +--------+
+ +-------------------+ | | | PTE63 |
+ | | : STE | | +-->+--------+ +0x0100
+ | PGE2 | PME0 : STE | | | PTE64 |
+ | | : STE | | +--------+
+ +-------------------+ | | PTE127 |
+ | | : STE | +------>+--------+ +0x0200
+ | PGE3 | PME0 : STE | | PTE128 |
+ | | : STE | +--------+
+ +-------------------+ | PTE191 |
+ +--------+ +0x0300
+
+Each Page Directory (PGD) is 16KB (page size) in size and is divided into 64 entries (PGEs). Each
+PGE contains one Page Mid Directory (PMD).
+
+Each PMD is 256 bytes in size and contains a single entry (PME). Each PME holds 64 FR451 MMU
+segment table entries of 4 bytes apiece. Each PME "points to" a page table. In practice, each STE
+points to a subset of the page table, the first to PT+0x0000, the second to PT+0x0100, the third to
+PT+0x200, and so on.
+
+Each PGE and PME covers 64MB of the total virtual address space.
+
+Each Page Table (PTD) is 16KB (page size) in size, and is divided into 4096 entries (PTEs). Each
+entry can point to one 16KB page. In practice, each Linux page table is subdivided into 64 FR451
+MMU page tables. But they are all grouped together to make management easier, in particular rmap
+support is then trivial.
+
+Grouping page tables in this fashion makes PGE caching in SCR0/SCR1 more efficient because the
+coverage of the cached item is greater.
+
+Page tables for the vmalloc area are allocated at boot time and shared between all mm_structs.
+
+
+=================
+USER SPACE LAYOUT
+=================
+
+For MMU capable Linux, the regions userspace code are allowed to access are kept entirely separate
+from those dedicated to the kernel:
+
+ VIRTUAL ADDRESS SIZE PURPOSE
+ ================= ===== ===================================
+ 00000000-00003fff 4KB NULL pointer access trap
+ 00004000-01ffffff ~32MB lower mmap space (grows up)
+ 02000000-021fffff 2MB Stack space (grows down from top)
+ 02200000-nnnnnnnn Executable mapping
+ nnnnnnnn- brk space (grows up)
+ -bfffffff upper mmap space (grows down)
+
+This is so arranged so as to make best use of the 16KB page tables and the way in which PGEs/PMEs
+are cached by the TLB handler. The lower mmap space is filled first, and then the upper mmap space
+is filled.
+
+
+===============================
+GDB-STUB MMU DEBUGGING SERVICES
+===============================
+
+The gdb-stub included in this kernel provides a number of services to aid in the debugging of MMU
+related kernel services:
+
+ (*) Every time the kernel stops, certain state information is dumped into __debug_mmu. This
+ variable is defined in arch/frv/kernel/gdb-stub.c. Note that the gdbinit file in this
+ directory has some useful macros for dealing with this.
+
+ (*) __debug_mmu.tlb[]
+
+ This receives the current TLB contents. This can be viewed with the _tlb GDB macro:
+
+ (gdb) _tlb
+ tlb[0x00]: 01000005 00718203 01000002 00718203
+ tlb[0x01]: 01004002 006d4201 01004005 006d4203
+ tlb[0x02]: 01008002 006d0201 01008006 00004200
+ tlb[0x03]: 0100c006 007f4202 0100c002 0064c202
+ tlb[0x04]: 01110005 00774201 01110002 00774201
+ tlb[0x05]: 01114005 00770201 01114002 00770201
+ tlb[0x06]: 01118002 0076c201 01118005 0076c201
+ ...
+ tlb[0x3d]: 010f4002 00790200 001f4002 0054ca02
+ tlb[0x3e]: 010f8005 0078c201 010f8002 0078c201
+ tlb[0x3f]: 001fc002 0056ca01 001fc005 00538a01
+
+ (*) __debug_mmu.iamr[]
+ (*) __debug_mmu.damr[]
+
+ These receive the current IAMR and DAMR contents. These can be viewed with the _amr
+ GDB macro:
+
+ (gdb) _amr
+ AMRx DAMR IAMR
+ ==== ===================== =====================
+ amr0 : L:c0000000 P:00000cb9 : L:c0000000 P:000004b9
+ amr1 : L:01070005 P:006f9203 : L:0102c005 P:006a1201
+ amr2 : L:d8d00000 P:00000000 : L:d8d00000 P:00000000
+ amr3 : L:d8d04000 P:00534c0d : L:00000000 P:00000000
+ amr4 : L:d8d08000 P:00554c0d : L:00000000 P:00000000
+ amr5 : L:d8d0c000 P:00554c0d : L:00000000 P:00000000
+ amr6 : L:d8d10000 P:00000000 : L:00000000 P:00000000
+ amr7 : L:d8d14000 P:00000000 : L:00000000 P:00000000
+ amr8 : L:d8d18000 P:00000000
+ amr9 : L:d8d1c000 P:00000000
+ amr10: L:d8d20000 P:00000000
+ amr11: L:e0000000 P:e0000ccd
+
+ (*) The current task's page directory is bound to DAMR3.
+
+ This can be viewed with the _pgd GDB macro:
+
+ (gdb) _pgd
+ $3 = {{pge = {{ste = {0x554001, 0x554101, 0x554201, 0x554301, 0x554401,
+ 0x554501, 0x554601, 0x554701, 0x554801, 0x554901, 0x554a01,
+ 0x554b01, 0x554c01, 0x554d01, 0x554e01, 0x554f01, 0x555001,
+ 0x555101, 0x555201, 0x555301, 0x555401, 0x555501, 0x555601,
+ 0x555701, 0x555801, 0x555901, 0x555a01, 0x555b01, 0x555c01,
+ 0x555d01, 0x555e01, 0x555f01, 0x556001, 0x556101, 0x556201,
+ 0x556301, 0x556401, 0x556501, 0x556601, 0x556701, 0x556801,
+ 0x556901, 0x556a01, 0x556b01, 0x556c01, 0x556d01, 0x556e01,
+ 0x556f01, 0x557001, 0x557101, 0x557201, 0x557301, 0x557401,
+ 0x557501, 0x557601, 0x557701, 0x557801, 0x557901, 0x557a01,
+ 0x557b01, 0x557c01, 0x557d01, 0x557e01, 0x557f01}}}}, {pge = {{
+ ste = {0x0 <repeats 64 times>}}}} <repeats 51 times>, {pge = {{ste = {
+ 0x248001, 0x248101, 0x248201, 0x248301, 0x248401, 0x248501,
+ 0x248601, 0x248701, 0x248801, 0x248901, 0x248a01, 0x248b01,
+ 0x248c01, 0x248d01, 0x248e01, 0x248f01, 0x249001, 0x249101,
+ 0x249201, 0x249301, 0x249401, 0x249501, 0x249601, 0x249701,
+ 0x249801, 0x249901, 0x249a01, 0x249b01, 0x249c01, 0x249d01,
+ 0x249e01, 0x249f01, 0x24a001, 0x24a101, 0x24a201, 0x24a301,
+ 0x24a401, 0x24a501, 0x24a601, 0x24a701, 0x24a801, 0x24a901,
+ 0x24aa01, 0x24ab01, 0x24ac01, 0x24ad01, 0x24ae01, 0x24af01,
+ 0x24b001, 0x24b101, 0x24b201, 0x24b301, 0x24b401, 0x24b501,
+ 0x24b601, 0x24b701, 0x24b801, 0x24b901, 0x24ba01, 0x24bb01,
+ 0x24bc01, 0x24bd01, 0x24be01, 0x24bf01}}}}, {pge = {{ste = {
+ 0x0 <repeats 64 times>}}}} <repeats 11 times>}
+
+ (*) The PTD last used by the instruction TLB miss handler is attached to DAMR4.
+ (*) The PTD last used by the data TLB miss handler is attached to DAMR5.
+
+ These can be viewed with the _ptd_i and _ptd_d GDB macros:
+
+ (gdb) _ptd_d
+ $5 = {{pte = 0x0} <repeats 127 times>, {pte = 0x539b01}, {
+ pte = 0x0} <repeats 896 times>, {pte = 0x719303}, {pte = 0x6d5303}, {
+ pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {
+ pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x6a1303}, {
+ pte = 0x0} <repeats 12 times>, {pte = 0x709303}, {pte = 0x0}, {pte = 0x0},
+ {pte = 0x6fd303}, {pte = 0x6f9303}, {pte = 0x6f5303}, {pte = 0x0}, {
+ pte = 0x6ed303}, {pte = 0x531b01}, {pte = 0x50db01}, {
+ pte = 0x0} <repeats 13 times>, {pte = 0x5303}, {pte = 0x7f5303}, {
+ pte = 0x509b01}, {pte = 0x505b01}, {pte = 0x7c9303}, {pte = 0x7b9303}, {
+ pte = 0x7b5303}, {pte = 0x7b1303}, {pte = 0x7ad303}, {pte = 0x0}, {
+ pte = 0x0}, {pte = 0x7a1303}, {pte = 0x0}, {pte = 0x795303}, {pte = 0x0}, {
+ pte = 0x78d303}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {
+ pte = 0x0}, {pte = 0x775303}, {pte = 0x771303}, {pte = 0x76d303}, {
+ pte = 0x0}, {pte = 0x765303}, {pte = 0x7c5303}, {pte = 0x501b01}, {
+ pte = 0x4f1b01}, {pte = 0x4edb01}, {pte = 0x0}, {pte = 0x4f9b01}, {
+ pte = 0x4fdb01}, {pte = 0x0} <repeats 2992 times>}
+++ /dev/null
- ================================
- Fujitsu FR-V LINUX DOCUMENTATION
- ================================
-
-This directory contains documentation for the Fujitsu FR-V CPU architecture
-port of Linux.
-
-The following documents are available:
-
- (*) features.txt
-
- A description of the basic features inherent in this architecture port.
-
-
- (*) configuring.txt
-
- A summary of the configuration options particular to this architecture.
-
-
- (*) booting.txt
-
- A description of how to boot the kernel image and a summary of the kernel
- command line options.
-
-
- (*) gdbstub.txt
-
- A description of how to debug the kernel using GDB attached by serial
- port, and a summary of the services available.
-
-
- (*) mmu-layout.txt
-
- A description of the virtual and physical memory layout used in the
- MMU linux kernel, and the registers used to support it.
-
-
- (*) gdbinit
-
- An example .gdbinit file for use with GDB. It includes macros for viewing
- MMU state on the FR451. See mmu-layout.txt for more information.
-
-
- (*) clock.txt
-
- A description of the CPU clock scaling interface.
-
-
- (*) atomic-ops.txt
-
- A description of how the FR-V kernel's atomic operations work.
+++ /dev/null
- =====================================
- FUJITSU FR-V KERNEL ATOMIC OPERATIONS
- =====================================
-
-On the FR-V CPUs, there is only one atomic Read-Modify-Write operation: the SWAP/SWAPI
-instruction. Unfortunately, this alone can't be used to implement the following operations:
-
- (*) Atomic add to memory
-
- (*) Atomic subtract from memory
-
- (*) Atomic bit modification (set, clear or invert)
-
- (*) Atomic compare and exchange
-
-On such CPUs, the standard way of emulating such operations in uniprocessor mode is to disable
-interrupts, but on the FR-V CPUs, modifying the PSR takes a lot of clock cycles, and it has to be
-done twice. This means the CPU runs for a relatively long time with interrupts disabled,
-potentially having a great effect on interrupt latency.
-
-
-=============
-NEW ALGORITHM
-=============
-
-To get around this, the following algorithm has been implemented. It operates in a way similar to
-the LL/SC instruction pairs supported on a number of platforms.
-
- (*) The CCCR.CC3 register is reserved within the kernel to act as an atomic modify abort flag.
-
- (*) In the exception prologues run on kernel->kernel entry, CCCR.CC3 is set to 0 (Undefined
- state).
-
- (*) All atomic operations can then be broken down into the following algorithm:
-
- (1) Set ICC3.Z to true and set CC3 to True (ORCC/CKEQ/ORCR).
-
- (2) Load the value currently in the memory to be modified into a register.
-
- (3) Make changes to the value.
-
- (4) If CC3 is still True, simultaneously and atomically (by VLIW packing):
-
- (a) Store the modified value back to memory.
-
- (b) Set ICC3.Z to false (CORCC on GR29 is sufficient for this - GR29 holds the current
- task pointer in the kernel, and so is guaranteed to be non-zero).
-
- (5) If ICC3.Z is still true, go back to step (1).
-
-This works in a non-SMP environment because any interrupt or other exception that happens between
-steps (1) and (4) will set CC3 to the Undefined, thus aborting the store in (4a), and causing the
-condition in ICC3 to remain with the Z flag set, thus causing step (5) to loop back to step (1).
-
-
-This algorithm suffers from two problems:
-
- (1) The condition CCCR.CC3 is cleared unconditionally by an exception, irrespective of whether or
- not any changes were made to the target memory location during that exception.
-
- (2) The branch from step (5) back to step (1) may have to happen more than once until the store
- manages to take place. In theory, this loop could cycle forever because there are too many
- interrupts coming in, but it's unlikely.
-
-
-=======
-EXAMPLE
-=======
-
-Taking an example from include/asm-frv/atomic.h:
-
- static inline int atomic_add_return(int i, atomic_t *v)
- {
- unsigned long val;
-
- asm("0: \n"
-
-It starts by setting ICC3.Z to true for later use, and also transforming that into CC3 being in the
-True state.
-
- " orcc gr0,gr0,gr0,icc3 \n" <-- (1)
- " ckeq icc3,cc7 \n" <-- (1)
-
-Then it does the load. Note that the final phase of step (1) is done at the same time as the
-load. The VLIW packing ensures they are done simultaneously. The ".p" on the load must not be
-removed without swapping the order of these two instructions.
-
- " ld.p %M0,%1 \n" <-- (2)
- " orcr cc7,cc7,cc3 \n" <-- (1)
-
-Then the proposed modification is generated. Note that the old value can be retained if required
-(such as in test_and_set_bit()).
-
- " add%I2 %1,%2,%1 \n" <-- (3)
-
-Then it attempts to store the value back, contingent on no exception having cleared CC3 since it
-was set to True.
-
- " cst.p %1,%M0 ,cc3,#1 \n" <-- (4a)
-
-It simultaneously records the success or failure of the store in ICC3.Z.
-
- " corcc gr29,gr29,gr0 ,cc3,#1 \n" <-- (4b)
-
-Such that the branch can then be taken if the operation was aborted.
-
- " beq icc3,#0,0b \n" <-- (5)
- : "+U"(v->counter), "=&r"(val)
- : "NPr"(i)
- : "memory", "cc7", "cc3", "icc3"
- );
-
- return val;
- }
-
-
-=============
-CONFIGURATION
-=============
-
-The atomic ops implementation can be made inline or out-of-line by changing the
-CONFIG_FRV_OUTOFLINE_ATOMIC_OPS configuration variable. Making it out-of-line has a number of
-advantages:
-
- - The resulting kernel image may be smaller
- - Debugging is easier as atomic ops can just be stepped over and they can be breakpointed
-
-Keeping it inline also has a number of advantages:
-
- - The resulting kernel may be Faster
- - no out-of-line function calls need to be made
- - the compiler doesn't have half its registers clobbered by making a call
-
-The out-of-line implementations live in arch/frv/lib/atomic-ops.S.
+++ /dev/null
- =========================
- BOOTING FR-V LINUX KERNEL
- =========================
-
-======================
-PROVIDING A FILESYSTEM
-======================
-
-First of all, a root filesystem must be made available. This can be done in
-one of two ways:
-
- (1) NFS Export
-
- A filesystem should be constructed in a directory on an NFS server that
- the target board can reach. This directory should then be NFS exported
- such that the target board can read and write into it as root.
-
- (2) Flash Filesystem (JFFS2 Recommended)
-
- In this case, the image must be stored or built up on flash before it
- can be used. A complete image can be built using the mkfs.jffs2 or
- similar program and then downloaded and stored into flash by RedBoot.
-
-
-========================
-LOADING THE KERNEL IMAGE
-========================
-
-The kernel will need to be loaded into RAM by RedBoot (or by some alternative
-boot loader) before it can be run. The kernel image (arch/frv/boot/Image) may
-be loaded in one of three ways:
-
- (1) Load from Flash
-
- This is the simplest. RedBoot can store an image in the flash (see the
- RedBoot documentation) and then load it back into RAM. RedBoot keeps
- track of the load address, entry point and size, so the command to do
- this is simply:
-
- fis load linux
-
- The image is then ready to be executed.
-
- (2) Load by TFTP
-
- The following command will download a raw binary kernel image from the
- default server (as negotiated by BOOTP) and store it into RAM:
-
- load -b 0x00100000 -r /tftpboot/image.bin
-
- The image is then ready to be executed.
-
- (3) Load by Y-Modem
-
- The following command will download a raw binary kernel image across the
- serial port that RedBoot is currently using:
-
- load -m ymodem -b 0x00100000 -r zImage
-
- The serial client (such as minicom) must then be told to transmit the
- program by Y-Modem.
-
- When finished, the image will then be ready to be executed.
-
-
-==================
-BOOTING THE KERNEL
-==================
-
-Boot the image with the following RedBoot command:
-
- exec -c "<CMDLINE>" 0x00100000
-
-For example:
-
- exec -c "console=ttySM0,115200 ip=:::::dhcp root=/dev/mtdblock2 rw"
-
-This will start the kernel running. Note that if the GDB-stub is compiled in,
-then the kernel will immediately wait for GDB to connect over serial before
-doing anything else. See the section on kernel debugging with GDB.
-
-The kernel command line <CMDLINE> tells the kernel where its console is and
-how to find its root filesystem. This is made up of the following components,
-separated by spaces:
-
- (*) console=ttyS<x>[,<baud>[<parity>[<bits>[<flow>]]]]
-
- This specifies that the system console should output through on-chip
- serial port <x> (which can be "0" or "1").
-
- <baud> is a standard baud rate between 1200 and 115200 (default 9600).
-
- <parity> is a parity setting of "N", "O", "E", "M" or "S" for None, Odd,
- Even, Mark or Space. "None" is the default.
-
- <stop> is "7" or "8" for the number of bits per character. "8" is the
- default.
-
- <flow> is "r" to use flow control (XCTS on serial port 2 only). The
- default is to not use flow control.
-
- For example:
-
- console=ttyS0,115200
-
- To use the first on-chip serial port at baud rate 115200, no parity, 8
- bits, and no flow control.
-
- (*) root=/dev/<xxxx>
-
- This specifies the device upon which the root filesystem resides. For
- example:
-
- /dev/nfs NFS root filesystem
- /dev/mtdblock3 Fourth RedBoot partition on the System Flash
-
- (*) rw
-
- Start with the root filesystem mounted Read/Write.
-
- The remaining components are all optional:
-
- (*) ip=<ip>::::<host>:<iface>:<cfg>
-
- Configure the network interface. If <cfg> is "off" then <ip> should
- specify the IP address for the network device <iface>. <host> provide
- the hostname for the device.
-
- If <cfg> is "bootp" or "dhcp", then all of these parameters will be
- discovered by consulting a BOOTP or DHCP server.
-
- For example, the following might be used:
-
- ip=192.168.73.12::::frv:eth0:off
-
- This sets the IP address on the VDK motherboard RTL8029 ethernet chipset
- (eth0) to be 192.168.73.12, and sets the board's hostname to be "frv".
-
- (*) nfsroot=<server>:<dir>[,v<vers>]
-
- This is mandatory if "root=/dev/nfs" is given as an option. It tells the
- kernel the IP address of the NFS server providing its root filesystem,
- and the pathname on that server of the filesystem.
-
- The NFS version to use can also be specified. v2 and v3 are supported by
- Linux.
-
- For example:
-
- nfsroot=192.168.73.1:/nfsroot-frv
-
- (*) profile=1
-
- Turns on the kernel profiler (accessible through /proc/profile).
-
- (*) console=gdb0
-
- This can be used as an alternative to the "console=ttyS..." listed
- above. I tells the kernel to pass the console output to GDB if the
- gdbstub is compiled in to the kernel.
-
- If this is used, then the gdbstub passes the text to GDB, which then
- simply dumps it to its standard output.
-
- (*) mem=<xxx>M
-
- Normally the kernel will work out how much SDRAM it has by reading the
- SDRAM controller registers. That can be overridden with this
- option. This allows the kernel to be told that it has <xxx> megabytes of
- memory available.
-
- (*) init=<prog> [<arg> [<arg> [<arg> ...]]]
-
- This tells the kernel what program to run initially. By default this is
- /sbin/init, but /sbin/sash or /bin/sh are common alternatives.
-
- (*) vdc=...
-
- This option configures the MB93493 companion chip visual display
- driver. Please see Documentation/fujitsu/mb93493/vdc.txt for more
- information.
+++ /dev/null
-Clock scaling
--------------
-
-The kernel supports scaling of CLCK.CMODE, CLCK.CM and CLKC.P0 clock
-registers. If built with CONFIG_PM and CONFIG_SYSCTL options enabled, four
-extra files will appear in the directory /proc/sys/pm/. Reading these files
-will show:
-
- p0 -- current value of the P0 bit in CLKC register.
- cm -- current value of the CM bits in CLKC register.
- cmode -- current value of the CMODE bits in CLKC register.
-
-On all boards, the 'p0' file should also be writable, and either '1' or '0'
-can be rewritten, to set or clear the CLKC_P0 bit respectively, hence
-controlling whether the resource bus rate clock is halved.
-
-The 'cm' file should also be available on all boards. '0' can be written to it
-to shift the board into High-Speed mode (normal), and '1' can be written to
-shift the board into Medium-Speed mode. Selecting Low-Speed mode is not
-supported by this interface, even though some CPUs do support it.
-
-On the boards with FR405 CPU (i.e. CB60 and CB70), the 'cmode' file is also
-writable, allowing the CPU core speed (and other clock speeds) to be
-controlled from userspace.
-
-
-Determining current and possible settings
------------------------------------------
-
-The current state and the available masks can be found in /proc/cpuinfo. For
-example, on the CB70:
-
- # cat /proc/cpuinfo
- CPU-Series: fr400
- CPU-Core: fr405, gr0-31, BE, CCCR
- CPU: mb93405
- MMU: Prot
- FP-Media: fr0-31, Media
- System: mb93091-cb70, mb93090-mb00
- PM-Controls: cmode=0xd31f, cm=0x3, p0=0x3, suspend=0x9
- PM-Status: cmode=3, cm=0, p0=0
- Clock-In: 50.00 MHz
- Clock-Core: 300.00 MHz
- Clock-SDRAM: 100.00 MHz
- Clock-CBus: 100.00 MHz
- Clock-Res: 50.00 MHz
- Clock-Ext: 50.00 MHz
- Clock-DSU: 25.00 MHz
- BogoMips: 300.00
-
-And on the PDK, the PM lines look like the following:
-
- PM-Controls: cm=0x3, p0=0x3, suspend=0x9
- PM-Status: cmode=9, cm=0, p0=0
-
-The PM-Controls line, if present, will indicate which /proc/sys/pm files can
-be set to what values. The specification values are bitmasks; so, for example,
-"suspend=0x9" indicates that 0 and 3 can be written validly to
-/proc/sys/pm/suspend.
-
-The PM-Controls line will only be present if CONFIG_PM is configured to Y.
-
-The PM-Status line indicates which clock controls are set to which value. If
-the file can be read, then the suspend value must be 0, and so that's not
-included.
+++ /dev/null
- =======================================
- FUJITSU FR-V LINUX KERNEL CONFIGURATION
- =======================================
-
-=====================
-CONFIGURATION OPTIONS
-=====================
-
-The most important setting is in the "MMU support options" tab (the first
-presented in the configuration tools available):
-
- (*) "Kernel Type"
-
- This options allows selection of normal, MMU-requiring linux, and uClinux
- (which doesn't require an MMU and doesn't have inter-process protection).
-
-There are a number of settings in the "Processor type and features" section of
-the kernel configuration that need to be considered.
-
- (*) "CPU"
-
- The register and instruction sets at the core of the processor. This can
- only be set to "FR40x/45x/55x" at the moment - but this permits usage of
- the kernel with MB93091 CB10, CB11, CB30, CB41, CB60, CB70 and CB451
- CPU boards, and with the MB93093 PDK board.
-
- (*) "System"
-
- This option allows a choice of basic system. This governs the peripherals
- that are expected to be available.
-
- (*) "Motherboard"
-
- This specifies the type of motherboard being used, and the peripherals
- upon it. Currently only "MB93090-MB00" can be set here.
-
- (*) "Default cache-write mode"
-
- This controls the initial data cache write management mode. By default
- Write-Through is selected, but Write-Back (Copy-Back) can also be
- selected. This can be changed dynamically once the kernel is running (see
- features.txt).
-
-There are some architecture specific configuration options in the "General
-Setup" section of the kernel configuration too:
-
- (*) "Reserve memory uncached for (PCI) DMA"
-
- This requests that a uClinux kernel set aside some memory in an uncached
- window for the use as consistent DMA memory (mainly for PCI). At least a
- megabyte will be allocated in this way, possibly more. Any memory so
- reserved will not be available for normal allocations.
-
- (*) "Kernel support for ELF-FDPIC binaries"
-
- This enables the binary-format driver for the new FDPIC ELF binaries that
- this platform normally uses. These binaries are totally relocatable -
- their separate sections can relocated independently, allowing them to be
- shared on uClinux where possible. This should normally be enabled.
-
- (*) "Kernel image protection"
-
- This makes the protection register governing access to the core kernel
- image prohibit access by userspace programs. This option is available on
- uClinux only.
-
-There are also a number of settings in the "Kernel Hacking" section of the
-kernel configuration especially for debugging a kernel on this
-architecture. See the "gdbstub.txt" file for information about those.
-
-
-======================
-DEFAULT CONFIGURATIONS
-======================
-
-The kernel sources include a number of example default configurations:
-
- (*) defconfig-mb93091
-
- Default configuration for the MB93091-VDK with both CPU board and
- MB93090-MB00 motherboard running uClinux.
-
-
- (*) defconfig-mb93091-fb
-
- Default configuration for the MB93091-VDK with CPU board,
- MB93090-MB00 motherboard, and DAV board running uClinux.
- Includes framebuffer driver.
-
-
- (*) defconfig-mb93093
-
- Default configuration for the MB93093-PDK board running uClinux.
-
-
- (*) defconfig-cb70-standalone
-
- Default configuration for the MB93091-VDK with only CB70 CPU board
- running uClinux. This will use the CB70's DM9000 for network access.
-
-
- (*) defconfig-mmu
-
- Default configuration for the MB93091-VDK with both CB451 CPU board and
- MB93090-MB00 motherboard running MMU linux.
-
- (*) defconfig-mmu-audio
-
- Default configuration for the MB93091-VDK with CB451 CPU board, DAV
- board, and MB93090-MB00 motherboard running MMU linux. Includes
- audio driver.
-
- (*) defconfig-mmu-fb
-
- Default configuration for the MB93091-VDK with CB451 CPU board, DAV
- board, and MB93090-MB00 motherboard running MMU linux. Includes
- framebuffer driver.
-
- (*) defconfig-mmu-standalone
-
- Default configuration for the MB93091-VDK with only CB451 CPU board
- running MMU linux.
-
-
-
+++ /dev/null
- ===========================
- FUJITSU FR-V LINUX FEATURES
- ===========================
-
-This kernel port has a number of features of which the user should be aware:
-
- (*) Linux and uClinux
-
- The FR-V architecture port supports both normal MMU linux and uClinux out
- of the same sources.
-
-
- (*) CPU support
-
- Support for the FR401, FR403, FR405, FR451 and FR555 CPUs should work with
- the same uClinux kernel configuration.
-
- In normal (MMU) Linux mode, only the FR451 CPU will work as that is the
- only one with a suitably featured CPU.
-
- The kernel is written and compiled with the assumption that only the
- bottom 32 GR registers and no FR registers will be used by the kernel
- itself, however all extra userspace registers will be saved on context
- switch. Note that since most CPUs can't support lazy switching, no attempt
- is made to do lazy register saving where that would be possible (FR555
- only currently).
-
-
- (*) Board support
-
- The board on which the kernel will run can be configured on the "Processor
- type and features" configuration tab.
-
- Set the System to "MB93093-PDK" to boot from the MB93093 (FR403) PDK.
-
- Set the System to "MB93091-VDK" to boot from the CB11, CB30, CB41, CB60,
- CB70 or CB451 VDK boards. Set the Motherboard setting to "MB93090-MB00" to
- boot with the standard ATA90590B VDK motherboard, and set it to "None" to
- boot without any motherboard.
-
-
- (*) Binary Formats
-
- The only userspace binary format supported is FDPIC ELF. Normal ELF, FLAT
- and AOUT binaries are not supported for this architecture.
-
- FDPIC ELF supports shared library and program interpreter facilities.
-
-
- (*) Scheduler Speed
-
- The kernel scheduler runs at 100Hz irrespective of the clock speed on this
- architecture. This value is set in asm/param.h (see the HZ macro defined
- there).
-
-
- (*) Normal (MMU) Linux Memory Layout.
-
- See mmu-layout.txt in this directory for a description of the normal linux
- memory layout
-
- See include/asm-frv/mem-layout.h for constants pertaining to the memory
- layout.
-
- See include/asm-frv/mb-regs.h for the constants pertaining to the I/O bus
- controller configuration.
-
-
- (*) uClinux Memory Layout
-
- The memory layout used by the uClinux kernel is as follows:
-
- 0x00000000 - 0x00000FFF Null pointer catch page
- 0x20000000 - 0x200FFFFF CS2# [PDK] FPGA
- 0xC0000000 - 0xCFFFFFFF SDRAM
- 0xC0000000 Base of Linux kernel image
- 0xE0000000 - 0xEFFFFFFF CS2# [VDK] SLBUS/PCI window
- 0xF0000000 - 0xF0FFFFFF CS5# MB93493 CSC area (DAV daughter board)
- 0xF1000000 - 0xF1FFFFFF CS7# [CB70/CB451] CPU-card PCMCIA port space
- 0xFC000000 - 0xFC0FFFFF CS1# [VDK] MB86943 config space
- 0xFC100000 - 0xFC1FFFFF CS6# [CB70/CB451] CPU-card DM9000 NIC space
- 0xFC100000 - 0xFC1FFFFF CS6# [PDK] AX88796 NIC space
- 0xFC200000 - 0xFC2FFFFF CS3# MB93493 CSR area (DAV daughter board)
- 0xFD000000 - 0xFDFFFFFF CS4# [CB70/CB451] CPU-card extra flash space
- 0xFE000000 - 0xFEFFFFFF Internal CPU peripherals
- 0xFF000000 - 0xFF1FFFFF CS0# Flash 1
- 0xFF200000 - 0xFF3FFFFF CS0# Flash 2
- 0xFFC00000 - 0xFFC0001F CS0# [VDK] FPGA
-
- The kernel reads the size of the SDRAM from the memory bus controller
- registers by default.
-
- The kernel initialisation code (1) adjusts the SDRAM base addresses to
- move the SDRAM to desired address, (2) moves the kernel image down to the
- bottom of SDRAM, (3) adjusts the bus controller registers to move I/O
- windows, and (4) rearranges the protection registers to protect all of
- this.
-
- The reasons for doing this are: (1) the page at address 0 should be
- inaccessible so that NULL pointer errors can be caught; and (2) the bottom
- three quarters are left unoccupied so that an FR-V CPU with an MMU can use
- it for virtual userspace mappings.
-
- See include/asm-frv/mem-layout.h for constants pertaining to the memory
- layout.
-
- See include/asm-frv/mb-regs.h for the constants pertaining to the I/O bus
- controller configuration.
-
-
- (*) uClinux Memory Protection
-
- A DAMPR register is used to cover the entire region used for I/O
- (0xE0000000 - 0xFFFFFFFF). This permits the kernel to make uncached
- accesses to this region. Userspace is not permitted to access it.
-
- The DAMPR/IAMPR protection registers not in use for any other purpose are
- tiled over the top of the SDRAM such that:
-
- (1) The core kernel image is covered by as small a tile as possible
- granting only the kernel access to the underlying data, whilst
- making sure no SDRAM is actually made unavailable by this approach.
-
- (2) All other tiles are arranged to permit userspace access to the rest
- of the SDRAM.
-
- Barring point (1), there is nothing to protect kernel data against
- userspace damage - but this is uClinux.
-
-
- (*) Exceptions and Fixups
-
- Since the FR40x and FR55x CPUs that do not have full MMUs generate
- imprecise data error exceptions, there are currently no automatic fixup
- services available in uClinux. This includes misaligned memory access
- fixups.
-
- Userspace EFAULT errors can be trapped by issuing a MEMBAR instruction and
- forcing the fault to happen there.
-
- On the FR451, however, data exceptions are mostly precise, and so
- exception fixup handling is implemented as normal.
-
-
- (*) Userspace Breakpoints
-
- The ptrace() system call supports the following userspace debugging
- features:
-
- (1) Hardware assisted single step.
-
- (2) Breakpoint via the FR-V "BREAK" instruction.
-
- (3) Breakpoint via the FR-V "TIRA GR0, #1" instruction.
-
- (4) Syscall entry/exit trap.
-
- Each of the above generates a SIGTRAP.
-
-
- (*) On-Chip Serial Ports
-
- The FR-V on-chip serial ports are made available as ttyS0 and ttyS1. Note
- that if the GDB stub is compiled in, ttyS1 will not actually be available
- as it will be being used for the GDB stub.
-
- These ports can be made by:
-
- mknod /dev/ttyS0 c 4 64
- mknod /dev/ttyS1 c 4 65
-
-
- (*) Maskable Interrupts
-
- Level 15 (Non-maskable) interrupts are dealt with by the GDB stub if
- present, and cause a panic if not. If the GDB stub is present, ttyS1's
- interrupts are rated at level 15.
-
- All other interrupts are distributed over the set of available priorities
- so that no IRQs are shared where possible. The arch interrupt handling
- routines attempt to disentangle the various sources available through the
- CPU's own multiplexor, and those on off-CPU peripherals.
-
-
- (*) Accessing PCI Devices
-
- Where PCI is available, care must be taken when dealing with drivers that
- access PCI devices. PCI devices present their data in little-endian form,
- but the CPU sees it in big-endian form. The macros in asm/io.h try to get
- this right, but may not under all circumstances...
-
-
- (*) Ax88796 Ethernet Driver
-
- The MB93093 PDK board has an Ax88796 ethernet chipset (an NE2000 clone). A
- driver has been written to deal specifically with this. The driver
- provides MII services for the card.
-
- The driver can be configured by running make xconfig, and going to:
-
- (*) Network device support
- - turn on "Network device support"
- (*) Ethernet (10 or 100Mbit)
- - turn on "Ethernet (10 or 100Mbit)"
- - turn on "AX88796 NE2000 compatible chipset"
-
- The driver can be found in:
-
- drivers/net/ax88796.c
- include/asm/ax88796.h
-
-
- (*) WorkRAM Driver
-
- This driver provides a character device that permits access to the WorkRAM
- that can be found on the FR451 CPU. Each page is accessible through a
- separate minor number, thereby permitting each page to have its own
- filesystem permissions set on the device file.
-
- The device files should be:
-
- mknod /dev/frv/workram0 c 240 0
- mknod /dev/frv/workram1 c 240 1
- mknod /dev/frv/workram2 c 240 2
- ...
-
- The driver will not permit the opening of any device file that does not
- correspond to at least a partial page of WorkRAM. So the first device file
- is the only one available on the FR451. If any other CPU is detected, none
- of the devices will be openable.
-
- The devices can be accessed with read, write and llseek, and can also be
- mmapped. If they're mmapped, they will only map at the appropriate
- 0x7e8nnnnn address on linux and at the 0xfe8nnnnn address on uClinux. If
- MAP_FIXED is not specified, the appropriate address will be chosen anyway.
-
- The mappings must be MAP_SHARED not MAP_PRIVATE, and must not be
- PROT_EXEC. They must also start at file offset 0, and must not be longer
- than one page in size.
-
- This driver can be configured by running make xconfig, and going to:
-
- (*) Character devices
- - turn on "Fujitsu FR-V CPU WorkRAM support"
-
-
- (*) Dynamic data cache write mode changing
-
- It is possible to view and to change the data cache's write mode through
- the /proc/sys/frv/cache-mode file while the kernel is running. There are
- two modes available:
-
- NAME MEANING
- ===== ==========================================
- wthru Data cache is in Write-Through mode
- wback Data cache is in Write-Back/Copy-Back mode
-
- To read the cache mode:
-
- # cat /proc/sys/frv/cache-mode
- wthru
-
- To change the cache mode:
-
- # echo wback >/proc/sys/frv/cache-mode
- # cat /proc/sys/frv/cache-mode
- wback
-
-
- (*) MMU Context IDs and Pinning
-
- On MMU Linux the CPU supports the concept of a context ID in its MMU to
- make it more efficient (TLB entries are labelled with a context ID to link
- them to specific tasks).
-
- Normally once a context ID is allocated, it will remain affixed to a task
- or CLONE_VM'd group of tasks for as long as it exists. However, since the
- kernel is capable of supporting more tasks than there are possible ID
- numbers, the kernel will pass context IDs from one task to another if
- there are insufficient available.
-
- The context ID currently in use by a task can be viewed in /proc:
-
- # grep CXNR /proc/1/status
- CXNR: 1
-
- Note that kernel threads do not have a userspace context, and so will not
- show a CXNR entry in that file.
-
- Under some circumstances, however, it is desirable to pin a context ID on
- a process such that the kernel won't pass it on. This can be done by
- writing the process ID of the target process to a special file:
-
- # echo 17 >/proc/sys/frv/pin-cxnr
-
- Reading from the file will then show the context ID pinned.
-
- # cat /proc/sys/frv/pin-cxnr
- 4
-
- The context ID will remain pinned as long as any process is using that
- context, i.e.: when the all the subscribing processes have exited or
- exec'd; or when an unpinning request happens:
-
- # echo 0 >/proc/sys/frv/pin-cxnr
-
- When there isn't a pinned context, the file shows -1:
-
- # cat /proc/sys/frv/pin-cxnr
- -1
+++ /dev/null
-set remotebreak 1
-
-define _amr
-
-printf "AMRx DAMR IAMR \n"
-printf "==== ===================== =====================\n"
-printf "amr0 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x0].L,__debug_mmu.damr[0x0].P,__debug_mmu.iamr[0x0].L,__debug_mmu.iamr[0x0].P
-printf "amr1 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x1].L,__debug_mmu.damr[0x1].P,__debug_mmu.iamr[0x1].L,__debug_mmu.iamr[0x1].P
-printf "amr2 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x2].L,__debug_mmu.damr[0x2].P,__debug_mmu.iamr[0x2].L,__debug_mmu.iamr[0x2].P
-printf "amr3 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x3].L,__debug_mmu.damr[0x3].P,__debug_mmu.iamr[0x3].L,__debug_mmu.iamr[0x3].P
-printf "amr4 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x4].L,__debug_mmu.damr[0x4].P,__debug_mmu.iamr[0x4].L,__debug_mmu.iamr[0x4].P
-printf "amr5 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x5].L,__debug_mmu.damr[0x5].P,__debug_mmu.iamr[0x5].L,__debug_mmu.iamr[0x5].P
-printf "amr6 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x6].L,__debug_mmu.damr[0x6].P,__debug_mmu.iamr[0x6].L,__debug_mmu.iamr[0x6].P
-printf "amr7 : L:%08lx P:%08lx : L:%08lx P:%08lx\n",__debug_mmu.damr[0x7].L,__debug_mmu.damr[0x7].P,__debug_mmu.iamr[0x7].L,__debug_mmu.iamr[0x7].P
-
-printf "amr8 : L:%08lx P:%08lx\n",__debug_mmu.damr[0x8].L,__debug_mmu.damr[0x8].P
-printf "amr9 : L:%08lx P:%08lx\n",__debug_mmu.damr[0x9].L,__debug_mmu.damr[0x9].P
-printf "amr10: L:%08lx P:%08lx\n",__debug_mmu.damr[0xa].L,__debug_mmu.damr[0xa].P
-printf "amr11: L:%08lx P:%08lx\n",__debug_mmu.damr[0xb].L,__debug_mmu.damr[0xb].P
-
-end
-
-
-define _tlb
-printf "tlb[0x00]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x0].L,__debug_mmu.tlb[0x0].P,__debug_mmu.tlb[0x40+0x0].L,__debug_mmu.tlb[0x40+0x0].P
-printf "tlb[0x01]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1].L,__debug_mmu.tlb[0x1].P,__debug_mmu.tlb[0x40+0x1].L,__debug_mmu.tlb[0x40+0x1].P
-printf "tlb[0x02]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2].L,__debug_mmu.tlb[0x2].P,__debug_mmu.tlb[0x40+0x2].L,__debug_mmu.tlb[0x40+0x2].P
-printf "tlb[0x03]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3].L,__debug_mmu.tlb[0x3].P,__debug_mmu.tlb[0x40+0x3].L,__debug_mmu.tlb[0x40+0x3].P
-printf "tlb[0x04]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x4].L,__debug_mmu.tlb[0x4].P,__debug_mmu.tlb[0x40+0x4].L,__debug_mmu.tlb[0x40+0x4].P
-printf "tlb[0x05]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x5].L,__debug_mmu.tlb[0x5].P,__debug_mmu.tlb[0x40+0x5].L,__debug_mmu.tlb[0x40+0x5].P
-printf "tlb[0x06]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x6].L,__debug_mmu.tlb[0x6].P,__debug_mmu.tlb[0x40+0x6].L,__debug_mmu.tlb[0x40+0x6].P
-printf "tlb[0x07]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x7].L,__debug_mmu.tlb[0x7].P,__debug_mmu.tlb[0x40+0x7].L,__debug_mmu.tlb[0x40+0x7].P
-printf "tlb[0x08]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x8].L,__debug_mmu.tlb[0x8].P,__debug_mmu.tlb[0x40+0x8].L,__debug_mmu.tlb[0x40+0x8].P
-printf "tlb[0x09]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x9].L,__debug_mmu.tlb[0x9].P,__debug_mmu.tlb[0x40+0x9].L,__debug_mmu.tlb[0x40+0x9].P
-printf "tlb[0x0a]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xa].L,__debug_mmu.tlb[0xa].P,__debug_mmu.tlb[0x40+0xa].L,__debug_mmu.tlb[0x40+0xa].P
-printf "tlb[0x0b]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xb].L,__debug_mmu.tlb[0xb].P,__debug_mmu.tlb[0x40+0xb].L,__debug_mmu.tlb[0x40+0xb].P
-printf "tlb[0x0c]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xc].L,__debug_mmu.tlb[0xc].P,__debug_mmu.tlb[0x40+0xc].L,__debug_mmu.tlb[0x40+0xc].P
-printf "tlb[0x0d]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xd].L,__debug_mmu.tlb[0xd].P,__debug_mmu.tlb[0x40+0xd].L,__debug_mmu.tlb[0x40+0xd].P
-printf "tlb[0x0e]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xe].L,__debug_mmu.tlb[0xe].P,__debug_mmu.tlb[0x40+0xe].L,__debug_mmu.tlb[0x40+0xe].P
-printf "tlb[0x0f]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0xf].L,__debug_mmu.tlb[0xf].P,__debug_mmu.tlb[0x40+0xf].L,__debug_mmu.tlb[0x40+0xf].P
-printf "tlb[0x10]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x10].L,__debug_mmu.tlb[0x10].P,__debug_mmu.tlb[0x40+0x10].L,__debug_mmu.tlb[0x40+0x10].P
-printf "tlb[0x11]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x11].L,__debug_mmu.tlb[0x11].P,__debug_mmu.tlb[0x40+0x11].L,__debug_mmu.tlb[0x40+0x11].P
-printf "tlb[0x12]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x12].L,__debug_mmu.tlb[0x12].P,__debug_mmu.tlb[0x40+0x12].L,__debug_mmu.tlb[0x40+0x12].P
-printf "tlb[0x13]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x13].L,__debug_mmu.tlb[0x13].P,__debug_mmu.tlb[0x40+0x13].L,__debug_mmu.tlb[0x40+0x13].P
-printf "tlb[0x14]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x14].L,__debug_mmu.tlb[0x14].P,__debug_mmu.tlb[0x40+0x14].L,__debug_mmu.tlb[0x40+0x14].P
-printf "tlb[0x15]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x15].L,__debug_mmu.tlb[0x15].P,__debug_mmu.tlb[0x40+0x15].L,__debug_mmu.tlb[0x40+0x15].P
-printf "tlb[0x16]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x16].L,__debug_mmu.tlb[0x16].P,__debug_mmu.tlb[0x40+0x16].L,__debug_mmu.tlb[0x40+0x16].P
-printf "tlb[0x17]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x17].L,__debug_mmu.tlb[0x17].P,__debug_mmu.tlb[0x40+0x17].L,__debug_mmu.tlb[0x40+0x17].P
-printf "tlb[0x18]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x18].L,__debug_mmu.tlb[0x18].P,__debug_mmu.tlb[0x40+0x18].L,__debug_mmu.tlb[0x40+0x18].P
-printf "tlb[0x19]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x19].L,__debug_mmu.tlb[0x19].P,__debug_mmu.tlb[0x40+0x19].L,__debug_mmu.tlb[0x40+0x19].P
-printf "tlb[0x1a]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1a].L,__debug_mmu.tlb[0x1a].P,__debug_mmu.tlb[0x40+0x1a].L,__debug_mmu.tlb[0x40+0x1a].P
-printf "tlb[0x1b]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1b].L,__debug_mmu.tlb[0x1b].P,__debug_mmu.tlb[0x40+0x1b].L,__debug_mmu.tlb[0x40+0x1b].P
-printf "tlb[0x1c]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1c].L,__debug_mmu.tlb[0x1c].P,__debug_mmu.tlb[0x40+0x1c].L,__debug_mmu.tlb[0x40+0x1c].P
-printf "tlb[0x1d]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1d].L,__debug_mmu.tlb[0x1d].P,__debug_mmu.tlb[0x40+0x1d].L,__debug_mmu.tlb[0x40+0x1d].P
-printf "tlb[0x1e]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1e].L,__debug_mmu.tlb[0x1e].P,__debug_mmu.tlb[0x40+0x1e].L,__debug_mmu.tlb[0x40+0x1e].P
-printf "tlb[0x1f]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x1f].L,__debug_mmu.tlb[0x1f].P,__debug_mmu.tlb[0x40+0x1f].L,__debug_mmu.tlb[0x40+0x1f].P
-printf "tlb[0x20]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x20].L,__debug_mmu.tlb[0x20].P,__debug_mmu.tlb[0x40+0x20].L,__debug_mmu.tlb[0x40+0x20].P
-printf "tlb[0x21]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x21].L,__debug_mmu.tlb[0x21].P,__debug_mmu.tlb[0x40+0x21].L,__debug_mmu.tlb[0x40+0x21].P
-printf "tlb[0x22]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x22].L,__debug_mmu.tlb[0x22].P,__debug_mmu.tlb[0x40+0x22].L,__debug_mmu.tlb[0x40+0x22].P
-printf "tlb[0x23]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x23].L,__debug_mmu.tlb[0x23].P,__debug_mmu.tlb[0x40+0x23].L,__debug_mmu.tlb[0x40+0x23].P
-printf "tlb[0x24]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x24].L,__debug_mmu.tlb[0x24].P,__debug_mmu.tlb[0x40+0x24].L,__debug_mmu.tlb[0x40+0x24].P
-printf "tlb[0x25]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x25].L,__debug_mmu.tlb[0x25].P,__debug_mmu.tlb[0x40+0x25].L,__debug_mmu.tlb[0x40+0x25].P
-printf "tlb[0x26]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x26].L,__debug_mmu.tlb[0x26].P,__debug_mmu.tlb[0x40+0x26].L,__debug_mmu.tlb[0x40+0x26].P
-printf "tlb[0x27]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x27].L,__debug_mmu.tlb[0x27].P,__debug_mmu.tlb[0x40+0x27].L,__debug_mmu.tlb[0x40+0x27].P
-printf "tlb[0x28]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x28].L,__debug_mmu.tlb[0x28].P,__debug_mmu.tlb[0x40+0x28].L,__debug_mmu.tlb[0x40+0x28].P
-printf "tlb[0x29]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x29].L,__debug_mmu.tlb[0x29].P,__debug_mmu.tlb[0x40+0x29].L,__debug_mmu.tlb[0x40+0x29].P
-printf "tlb[0x2a]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2a].L,__debug_mmu.tlb[0x2a].P,__debug_mmu.tlb[0x40+0x2a].L,__debug_mmu.tlb[0x40+0x2a].P
-printf "tlb[0x2b]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2b].L,__debug_mmu.tlb[0x2b].P,__debug_mmu.tlb[0x40+0x2b].L,__debug_mmu.tlb[0x40+0x2b].P
-printf "tlb[0x2c]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2c].L,__debug_mmu.tlb[0x2c].P,__debug_mmu.tlb[0x40+0x2c].L,__debug_mmu.tlb[0x40+0x2c].P
-printf "tlb[0x2d]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2d].L,__debug_mmu.tlb[0x2d].P,__debug_mmu.tlb[0x40+0x2d].L,__debug_mmu.tlb[0x40+0x2d].P
-printf "tlb[0x2e]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2e].L,__debug_mmu.tlb[0x2e].P,__debug_mmu.tlb[0x40+0x2e].L,__debug_mmu.tlb[0x40+0x2e].P
-printf "tlb[0x2f]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x2f].L,__debug_mmu.tlb[0x2f].P,__debug_mmu.tlb[0x40+0x2f].L,__debug_mmu.tlb[0x40+0x2f].P
-printf "tlb[0x30]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x30].L,__debug_mmu.tlb[0x30].P,__debug_mmu.tlb[0x40+0x30].L,__debug_mmu.tlb[0x40+0x30].P
-printf "tlb[0x31]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x31].L,__debug_mmu.tlb[0x31].P,__debug_mmu.tlb[0x40+0x31].L,__debug_mmu.tlb[0x40+0x31].P
-printf "tlb[0x32]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x32].L,__debug_mmu.tlb[0x32].P,__debug_mmu.tlb[0x40+0x32].L,__debug_mmu.tlb[0x40+0x32].P
-printf "tlb[0x33]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x33].L,__debug_mmu.tlb[0x33].P,__debug_mmu.tlb[0x40+0x33].L,__debug_mmu.tlb[0x40+0x33].P
-printf "tlb[0x34]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x34].L,__debug_mmu.tlb[0x34].P,__debug_mmu.tlb[0x40+0x34].L,__debug_mmu.tlb[0x40+0x34].P
-printf "tlb[0x35]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x35].L,__debug_mmu.tlb[0x35].P,__debug_mmu.tlb[0x40+0x35].L,__debug_mmu.tlb[0x40+0x35].P
-printf "tlb[0x36]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x36].L,__debug_mmu.tlb[0x36].P,__debug_mmu.tlb[0x40+0x36].L,__debug_mmu.tlb[0x40+0x36].P
-printf "tlb[0x37]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x37].L,__debug_mmu.tlb[0x37].P,__debug_mmu.tlb[0x40+0x37].L,__debug_mmu.tlb[0x40+0x37].P
-printf "tlb[0x38]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x38].L,__debug_mmu.tlb[0x38].P,__debug_mmu.tlb[0x40+0x38].L,__debug_mmu.tlb[0x40+0x38].P
-printf "tlb[0x39]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x39].L,__debug_mmu.tlb[0x39].P,__debug_mmu.tlb[0x40+0x39].L,__debug_mmu.tlb[0x40+0x39].P
-printf "tlb[0x3a]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3a].L,__debug_mmu.tlb[0x3a].P,__debug_mmu.tlb[0x40+0x3a].L,__debug_mmu.tlb[0x40+0x3a].P
-printf "tlb[0x3b]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3b].L,__debug_mmu.tlb[0x3b].P,__debug_mmu.tlb[0x40+0x3b].L,__debug_mmu.tlb[0x40+0x3b].P
-printf "tlb[0x3c]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3c].L,__debug_mmu.tlb[0x3c].P,__debug_mmu.tlb[0x40+0x3c].L,__debug_mmu.tlb[0x40+0x3c].P
-printf "tlb[0x3d]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3d].L,__debug_mmu.tlb[0x3d].P,__debug_mmu.tlb[0x40+0x3d].L,__debug_mmu.tlb[0x40+0x3d].P
-printf "tlb[0x3e]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3e].L,__debug_mmu.tlb[0x3e].P,__debug_mmu.tlb[0x40+0x3e].L,__debug_mmu.tlb[0x40+0x3e].P
-printf "tlb[0x3f]: %08lx %08lx %08lx %08lx\n",__debug_mmu.tlb[0x3f].L,__debug_mmu.tlb[0x3f].P,__debug_mmu.tlb[0x40+0x3f].L,__debug_mmu.tlb[0x40+0x3f].P
-end
-
-
-define _pgd
-p (pgd_t[0x40])*(pgd_t*)(__debug_mmu.damr[0x3].L)
-end
-
-define _ptd_i
-p (pte_t[0x1000])*(pte_t*)(__debug_mmu.damr[0x4].L)
-end
-
-define _ptd_d
-p (pte_t[0x1000])*(pte_t*)(__debug_mmu.damr[0x5].L)
-end
+++ /dev/null
- ====================
- DEBUGGING FR-V LINUX
- ====================
-
-
-The kernel contains a GDB stub that talks GDB remote protocol across a serial
-port. This permits GDB to single step through the kernel, set breakpoints and
-trap exceptions that happen in kernel space and interrupt execution. It also
-permits the NMI interrupt button or serial port events to jump the kernel into
-the debugger.
-
-On the CPUs that have on-chip UARTs (FR400, FR403, FR405, FR555), the
-GDB stub hijacks a serial port for its own purposes, and makes it
-generate level 15 interrupts (NMI). The kernel proper cannot see the serial
-port in question under these conditions.
-
-On the MB93091-VDK CPU boards, the GDB stub uses UART1, which would otherwise
-be /dev/ttyS1. On the MB93093-PDK, the GDB stub uses UART0. Therefore, on the
-PDK there is no externally accessible serial port and the serial port to
-which the touch screen is attached becomes /dev/ttyS0.
-
-Note that the GDB stub runs entirely within CPU debug mode, and so should not
-incur any exceptions or interrupts whilst it is active. In particular, note
-that the clock will lose time since it is implemented in software.
-
-
-==================
-KERNEL PREPARATION
-==================
-
-Firstly, a debuggable kernel must be built. To do this, unpack the kernel tree
-and copy the configuration that you wish to use to .config. Then reconfigure
-the following things on the "Kernel Hacking" tab:
-
- (*) "Include debugging information"
-
- Set this to "Y". This causes all C and Assembly files to be compiled
- to include debugging information.
-
- (*) "In-kernel GDB stub"
-
- Set this to "Y". This causes the GDB stub to be compiled into the
- kernel.
-
- (*) "Immediate activation"
-
- Set this to "Y" if you want the GDB stub to activate as soon as possible
- and wait for GDB to connect. This allows you to start tracing right from
- the beginning of start_kernel() in init/main.c.
-
- (*) "Console through GDB stub"
-
- Set this to "Y" if you wish to be able to use "console=gdb0" on the
- command line. That tells the kernel to pass system console messages to
- GDB (which then prints them on its standard output). This is useful when
- debugging the serial drivers that'd otherwise be used to pass console
- messages to the outside world.
-
-Then build as usual, download to the board and execute. Note that if
-"Immediate activation" was selected, then the kernel will wait for GDB to
-attach. If not, then the kernel will boot immediately and GDB will have to
-interrupt it or wait for an exception to occur before doing anything with
-the kernel.
-
-
-=========================
-KERNEL DEBUGGING WITH GDB
-=========================
-
-Set the serial port on the computer that's going to run GDB to the appropriate
-baud rate. Assuming the board's debug port is connected to ttyS0/COM1 on the
-computer doing the debugging:
-
- stty -F /dev/ttyS0 115200
-
-Then start GDB in the base of the kernel tree:
-
- frv-uclinux-gdb linux [uClinux]
-
-Or:
-
- frv-uclinux-gdb vmlinux [MMU linux]
-
-When the prompt appears:
-
- GNU gdb frv-031024
- Copyright 2003 Free Software Foundation, Inc.
- GDB is free software, covered by the GNU General Public License, and you are
- welcome to change it and/or distribute copies of it under certain conditions.
- Type "show copying" to see the conditions.
- There is absolutely no warranty for GDB. Type "show warranty" for details.
- This GDB was configured as "--host=i686-pc-linux-gnu --target=frv-uclinux"...
- (gdb)
-
-Attach to the board like this:
-
- (gdb) target remote /dev/ttyS0
- Remote debugging using /dev/ttyS0
- start_kernel () at init/main.c:395
- (gdb)
-
-This should show the appropriate lines from the source too. The kernel can
-then be debugged almost as if it's any other program.
-
-
-===============================
-INTERRUPTING THE RUNNING KERNEL
-===============================
-
-The kernel can be interrupted whilst it is running, causing a jump back to the
-GDB stub and the debugger:
-
- (*) Pressing Ctrl-C in GDB. This will cause GDB to try and interrupt the
- kernel by sending an RS232 BREAK over the serial line to the GDB
- stub. This will (mostly) immediately interrupt the kernel and return it
- to the debugger.
-
- (*) Pressing the NMI button on the board will also cause a jump into the
- debugger.
-
- (*) Setting a software breakpoint. This sets a break instruction at the
- desired location which the GDB stub then traps the exception for.
-
- (*) Setting a hardware breakpoint. The GDB stub is capable of using the IBAR
- and DBAR registers to assist debugging.
-
-Furthermore, the GDB stub will intercept a number of exceptions automatically
-if they are caused by kernel execution. It will also intercept BUG() macro
-invocation.
-
+++ /dev/null
- =================================
- INTERNAL KERNEL ABI FOR FR-V ARCH
- =================================
-
-The internal FRV kernel ABI is not quite the same as the userspace ABI. A
-number of the registers are used for special purposed, and the ABI is not
-consistent between modules vs core, and MMU vs no-MMU.
-
-This partly stems from the fact that FRV CPUs do not have a separate
-supervisor stack pointer, and most of them do not have any scratch
-registers, thus requiring at least one general purpose register to be
-clobbered in such an event. Also, within the kernel core, it is possible to
-simply jump or call directly between functions using a relative offset.
-This cannot be extended to modules for the displacement is likely to be too
-far. Thus in modules the address of a function to call must be calculated
-in a register and then used, requiring two extra instructions.
-
-This document has the following sections:
-
- (*) System call register ABI
- (*) CPU operating modes
- (*) Internal kernel-mode register ABI
- (*) Internal debug-mode register ABI
- (*) Virtual interrupt handling
-
-
-========================
-SYSTEM CALL REGISTER ABI
-========================
-
-When a system call is made, the following registers are effective:
-
- REGISTERS CALL RETURN
- =============== ======================= =======================
- GR7 System call number Preserved
- GR8 Syscall arg #1 Return value
- GR9-GR13 Syscall arg #2-6 Preserved
-
-
-===================
-CPU OPERATING MODES
-===================
-
-The FR-V CPU has three basic operating modes. In order of increasing
-capability:
-
- (1) User mode.
-
- Basic userspace running mode.
-
- (2) Kernel mode.
-
- Normal kernel mode. There are many additional control registers
- available that may be accessed in this mode, in addition to all the
- stuff available to user mode. This has two submodes:
-
- (a) Exceptions enabled (PSR.T == 1).
-
- Exceptions will invoke the appropriate normal kernel mode
- handler. On entry to the handler, the PSR.T bit will be cleared.
-
- (b) Exceptions disabled (PSR.T == 0).
-
- No exceptions or interrupts may happen. Any mandatory exceptions
- will cause the CPU to halt unless the CPU is told to jump into
- debug mode instead.
-
- (3) Debug mode.
-
- No exceptions may happen in this mode. Memory protection and
- management exceptions will be flagged for later consideration, but
- the exception handler won't be invoked. Debugging traps such as
- hardware breakpoints and watchpoints will be ignored. This mode is
- entered only by debugging events obtained from the other two modes.
-
- All kernel mode registers may be accessed, plus a few extra debugging
- specific registers.
-
-
-=================================
-INTERNAL KERNEL-MODE REGISTER ABI
-=================================
-
-There are a number of permanent register assignments that are set up by
-entry.S in the exception prologue. Note that there is a complete set of
-exception prologues for each of user->kernel transition and kernel->kernel
-transition. There are also user->debug and kernel->debug mode transition
-prologues.
-
-
- REGISTER FLAVOUR USE
- =============== ======= ==============================================
- GR1 Supervisor stack pointer
- GR15 Current thread info pointer
- GR16 GP-Rel base register for small data
- GR28 Current exception frame pointer (__frame)
- GR29 Current task pointer (current)
- GR30 Destroyed by kernel mode entry
- GR31 NOMMU Destroyed by debug mode entry
- GR31 MMU Destroyed by TLB miss kernel mode entry
- CCR.ICC2 Virtual interrupt disablement tracking
- CCCR.CC3 Cleared by exception prologue
- (atomic op emulation)
- SCR0 MMU See mmu-layout.txt.
- SCR1 MMU See mmu-layout.txt.
- SCR2 MMU Save for EAR0 (destroyed by icache insns
- in debug mode)
- SCR3 MMU Save for GR31 during debug exceptions
- DAMR/IAMR NOMMU Fixed memory protection layout.
- DAMR/IAMR MMU See mmu-layout.txt.
-
-
-Certain registers are also used or modified across function calls:
-
- REGISTER CALL RETURN
- =============== =============================== ======================
- GR0 Fixed Zero -
- GR2 Function call frame pointer
- GR3 Special Preserved
- GR3-GR7 - Clobbered
- GR8 Function call arg #1 Return value
- (or clobbered)
- GR9 Function call arg #2 Return value MSW
- (or clobbered)
- GR10-GR13 Function call arg #3-#6 Clobbered
- GR14 - Clobbered
- GR15-GR16 Special Preserved
- GR17-GR27 - Preserved
- GR28-GR31 Special Only accessed
- explicitly
- LR Return address after CALL Clobbered
- CCR/CCCR - Mostly Clobbered
-
-
-================================
-INTERNAL DEBUG-MODE REGISTER ABI
-================================
-
-This is the same as the kernel-mode register ABI for functions calls. The
-difference is that in debug-mode there's a different stack and a different
-exception frame. Almost all the global registers from kernel-mode
-(including the stack pointer) may be changed.
-
- REGISTER FLAVOUR USE
- =============== ======= ==============================================
- GR1 Debug stack pointer
- GR16 GP-Rel base register for small data
- GR31 Current debug exception frame pointer
- (__debug_frame)
- SCR3 MMU Saved value of GR31
-
-
-Note that debug mode is able to interfere with the kernel's emulated atomic
-ops, so it must be exceedingly careful not to do any that would interact
-with the main kernel in this regard. Hence the debug mode code (gdbstub) is
-almost completely self-contained. The only external code used is the
-sprintf family of functions.
-
-Furthermore, break.S is so complicated because single-step mode does not
-switch off on entry to an exception. That means unless manually disabled,
-single-stepping will blithely go on stepping into things like interrupts.
-See gdbstub.txt for more information.
-
-
-==========================
-VIRTUAL INTERRUPT HANDLING
-==========================
-
-Because accesses to the PSR is so slow, and to disable interrupts we have
-to access it twice (once to read and once to write), we don't actually
-disable interrupts at all if we don't have to. What we do instead is use
-the ICC2 condition code flags to note virtual disablement, such that if we
-then do take an interrupt, we note the flag, really disable interrupts, set
-another flag and resume execution at the point the interrupt happened.
-Setting condition flags as a side effect of an arithmetic or logical
-instruction is really fast. This use of the ICC2 only occurs within the
-kernel - it does not affect userspace.
-
-The flags we use are:
-
- (*) CCR.ICC2.Z [Zero flag]
-
- Set to virtually disable interrupts, clear when interrupts are
- virtually enabled. Can be modified by logical instructions without
- affecting the Carry flag.
-
- (*) CCR.ICC2.C [Carry flag]
-
- Clear to indicate hardware interrupts are really disabled, set otherwise.
-
-
-What happens is this:
-
- (1) Normal kernel-mode operation.
-
- ICC2.Z is 0, ICC2.C is 1.
-
- (2) An interrupt occurs. The exception prologue examines ICC2.Z and
- determines that nothing needs doing. This is done simply with an
- unlikely BEQ instruction.
-
- (3) The interrupts are disabled (local_irq_disable)
-
- ICC2.Z is set to 1.
-
- (4) If interrupts were then re-enabled (local_irq_enable):
-
- ICC2.Z would be set to 0.
-
- A TIHI #2 instruction (trap #2 if condition HI - Z==0 && C==0) would
- be used to trap if interrupts were now virtually enabled, but
- physically disabled - which they're not, so the trap isn't taken. The
- kernel would then be back to state (1).
-
- (5) An interrupt occurs. The exception prologue examines ICC2.Z and
- determines that the interrupt shouldn't actually have happened. It
- jumps aside, and there disabled interrupts by setting PSR.PIL to 14
- and then it clears ICC2.C.
-
- (6) If interrupts were then saved and disabled again (local_irq_save):
-
- ICC2.Z would be shifted into the save variable and masked off
- (giving a 1).
-
- ICC2.Z would then be set to 1 (thus unchanged), and ICC2.C would be
- unaffected (ie: 0).
-
- (7) If interrupts were then restored from state (6) (local_irq_restore):
-
- ICC2.Z would be set to indicate the result of XOR'ing the saved
- value (ie: 1) with 1, which gives a result of 0 - thus leaving
- ICC2.Z set.
-
- ICC2.C would remain unaffected (ie: 0).
-
- A TIHI #2 instruction would be used to again assay the current state,
- but this would do nothing as Z==1.
-
- (8) If interrupts were then enabled (local_irq_enable):
-
- ICC2.Z would be cleared. ICC2.C would be left unaffected. Both
- flags would now be 0.
-
- A TIHI #2 instruction again issued to assay the current state would
- then trap as both Z==0 [interrupts virtually enabled] and C==0
- [interrupts really disabled] would then be true.
-
- (9) The trap #2 handler would simply enable hardware interrupts
- (set PSR.PIL to 0), set ICC2.C to 1 and return.
-
-(10) Immediately upon returning, the pending interrupt would be taken.
-
-(11) The interrupt handler would take the path of actually processing the
- interrupt (ICC2.Z is clear, BEQ fails as per step (2)).
-
-(12) The interrupt handler would then set ICC2.C to 1 since hardware
- interrupts are definitely enabled - or else the kernel wouldn't be here.
-
-(13) On return from the interrupt handler, things would be back to state (1).
-
-This trap (#2) is only available in kernel mode. In user mode it will
-result in SIGILL.
+++ /dev/null
- =================================
- FR451 MMU LINUX MEMORY MANAGEMENT
- =================================
-
-============
-MMU HARDWARE
-============
-
-FR451 MMU Linux puts the MMU into EDAT mode whilst running. This means that it uses both the SAT
-registers and the DAT TLB to perform address translation.
-
-There are 8 IAMLR/IAMPR register pairs and 16 DAMLR/DAMPR register pairs for SAT mode.
-
-In DAT mode, there is also a TLB organised in cache format as 64 lines x 2 ways. Each line spans a
-16KB range of addresses, but can match a larger region.
-
-
-===========================
-MEMORY MANAGEMENT REGISTERS
-===========================
-
-Certain control registers are used by the kernel memory management routines:
-
- REGISTERS USAGE
- ====================== ==================================================
- IAMR0, DAMR0 Kernel image and data mappings
- IAMR1, DAMR1 First-chance TLB lookup mapping
- DAMR2 Page attachment for cache flush by page
- DAMR3 Current PGD mapping
- SCR0, DAMR4 Instruction TLB PGE/PTD cache
- SCR1, DAMR5 Data TLB PGE/PTD cache
- DAMR6-10 kmap_atomic() mappings
- DAMR11 I/O mapping
- CXNR mm_struct context ID
- TTBR Page directory (PGD) pointer (physical address)
-
-
-=====================
-GENERAL MEMORY LAYOUT
-=====================
-
-The physical memory layout is as follows:
-
- PHYSICAL ADDRESS CONTROLLER DEVICE
- =================== ============== =======================================
- 00000000 - BFFFFFFF SDRAM SDRAM area
- E0000000 - EFFFFFFF L-BUS CS2# VDK SLBUS/PCI window
- F0000000 - F0FFFFFF L-BUS CS5# MB93493 CSC area (DAV daughter board)
- F1000000 - F1FFFFFF L-BUS CS7# (CB70 CPU-card PCMCIA port I/O space)
- FC000000 - FC0FFFFF L-BUS CS1# VDK MB86943 config space
- FC100000 - FC1FFFFF L-BUS CS6# DM9000 NIC I/O space
- FC200000 - FC2FFFFF L-BUS CS3# MB93493 CSR area (DAV daughter board)
- FD000000 - FDFFFFFF L-BUS CS4# (CB70 CPU-card extra flash space)
- FE000000 - FEFFFFFF Internal CPU peripherals
- FF000000 - FF1FFFFF L-BUS CS0# Flash 1
- FF200000 - FF3FFFFF L-BUS CS0# Flash 2
- FFC00000 - FFC0001F L-BUS CS0# FPGA
-
-The virtual memory layout is:
-
- VIRTUAL ADDRESS PHYSICAL TRANSLATOR FLAGS SIZE OCCUPATION
- ================= ======== ============== ======= ======= ===================================
- 00004000-BFFFFFFF various TLB,xAMR1 D-N-??V 3GB Userspace
- C0000000-CFFFFFFF 00000000 xAMPR0 -L-S--V 256MB Kernel image and data
- D0000000-D7FFFFFF various TLB,xAMR1 D-NS??V 128MB vmalloc area
- D8000000-DBFFFFFF various TLB,xAMR1 D-NS??V 64MB kmap() area
- DC000000-DCFFFFFF various TLB 1MB Secondary kmap_atomic() frame
- DD000000-DD27FFFF various DAMR 160KB Primary kmap_atomic() frame
- DD040000 DAMR2/IAMR2 -L-S--V page Page cache flush attachment point
- DD080000 DAMR3 -L-SC-V page Page Directory (PGD)
- DD0C0000 DAMR4 -L-SC-V page Cached insn TLB Page Table lookup
- DD100000 DAMR5 -L-SC-V page Cached data TLB Page Table lookup
- DD140000 DAMR6 -L-S--V page kmap_atomic(KM_BOUNCE_READ)
- DD180000 DAMR7 -L-S--V page kmap_atomic(KM_SKB_SUNRPC_DATA)
- DD1C0000 DAMR8 -L-S--V page kmap_atomic(KM_SKB_DATA_SOFTIRQ)
- DD200000 DAMR9 -L-S--V page kmap_atomic(KM_USER0)
- DD240000 DAMR10 -L-S--V page kmap_atomic(KM_USER1)
- E0000000-FFFFFFFF E0000000 DAMR11 -L-SC-V 512MB I/O region
-
-IAMPR1 and DAMPR1 are used as an extension to the TLB.
-
-
-====================
-KMAP AND KMAP_ATOMIC
-====================
-
-To access pages in the page cache (which may not be directly accessible if highmem is available),
-the kernel calls kmap(), does the access and then calls kunmap(); or it calls kmap_atomic(), does
-the access and then calls kunmap_atomic().
-
-kmap() creates an attachment between an arbitrary inaccessible page and a range of virtual
-addresses by installing a PTE in a special page table. The kernel can then access this page as it
-wills. When it's finished, the kernel calls kunmap() to clear the PTE.
-
-kmap_atomic() does something slightly different. In the interests of speed, it chooses one of two
-strategies:
-
- (1) If possible, kmap_atomic() attaches the requested page to one of DAMPR5 through DAMPR10
- register pairs; and the matching kunmap_atomic() clears the DAMPR. This makes high memory
- support really fast as there's no need to flush the TLB or modify the page tables. The DAMLR
- registers being used for this are preset during boot and don't change over the lifetime of the
- process. There's a direct mapping between the first few kmap_atomic() types, DAMR number and
- virtual address slot.
-
- However, there are more kmap_atomic() types defined than there are DAMR registers available,
- so we fall back to:
-
- (2) kmap_atomic() uses a slot in the secondary frame (determined by the type parameter), and then
- locks an entry in the TLB to translate that slot to the specified page. The number of slots is
- obviously limited, and their positions are controlled such that each slot is matched by a
- different line in the TLB. kunmap() ejects the entry from the TLB.
-
-Note that the first three kmap atomic types are really just declared as placeholders. The DAMPR
-registers involved are actually modified directly.
-
-Also note that kmap() itself may sleep, kmap_atomic() may never sleep and both always succeed;
-furthermore, a driver using kmap() may sleep before calling kunmap(), but may not sleep before
-calling kunmap_atomic() if it had previously called kmap_atomic().
-
-
-===============================
-USING MORE THAN 256MB OF MEMORY
-===============================
-
-The kernel cannot access more than 256MB of memory directly. The physical layout, however, permits
-up to 3GB of SDRAM (possibly 3.25GB) to be made available. By using CONFIG_HIGHMEM, the kernel can
-allow userspace (by way of page tables) and itself (by way of kmap) to deal with the memory
-allocation.
-
-External devices can, of course, still DMA to and from all of the SDRAM, even if the kernel can't
-see it directly. The kernel translates page references into real addresses for communicating to the
-devices.
-
-
-===================
-PAGE TABLE TOPOLOGY
-===================
-
-The page tables are arranged in 2-layer format. There is a middle layer (PMD) that would be used in
-3-layer format tables but that is folded into the top layer (PGD) and so consumes no extra memory
-or processing power.
-
- +------+ PGD PMD
- | TTBR |--->+-------------------+
- +------+ | | : STE |
- | PGE0 | PME0 : STE |
- | | : STE |
- +-------------------+ Page Table
- | | : STE -------------->+--------+ +0x0000
- | PGE1 | PME0 : STE -----------+ | PTE0 |
- | | : STE -------+ | +--------+
- +-------------------+ | | | PTE63 |
- | | : STE | | +-->+--------+ +0x0100
- | PGE2 | PME0 : STE | | | PTE64 |
- | | : STE | | +--------+
- +-------------------+ | | PTE127 |
- | | : STE | +------>+--------+ +0x0200
- | PGE3 | PME0 : STE | | PTE128 |
- | | : STE | +--------+
- +-------------------+ | PTE191 |
- +--------+ +0x0300
-
-Each Page Directory (PGD) is 16KB (page size) in size and is divided into 64 entries (PGEs). Each
-PGE contains one Page Mid Directory (PMD).
-
-Each PMD is 256 bytes in size and contains a single entry (PME). Each PME holds 64 FR451 MMU
-segment table entries of 4 bytes apiece. Each PME "points to" a page table. In practice, each STE
-points to a subset of the page table, the first to PT+0x0000, the second to PT+0x0100, the third to
-PT+0x200, and so on.
-
-Each PGE and PME covers 64MB of the total virtual address space.
-
-Each Page Table (PTD) is 16KB (page size) in size, and is divided into 4096 entries (PTEs). Each
-entry can point to one 16KB page. In practice, each Linux page table is subdivided into 64 FR451
-MMU page tables. But they are all grouped together to make management easier, in particular rmap
-support is then trivial.
-
-Grouping page tables in this fashion makes PGE caching in SCR0/SCR1 more efficient because the
-coverage of the cached item is greater.
-
-Page tables for the vmalloc area are allocated at boot time and shared between all mm_structs.
-
-
-=================
-USER SPACE LAYOUT
-=================
-
-For MMU capable Linux, the regions userspace code are allowed to access are kept entirely separate
-from those dedicated to the kernel:
-
- VIRTUAL ADDRESS SIZE PURPOSE
- ================= ===== ===================================
- 00000000-00003fff 4KB NULL pointer access trap
- 00004000-01ffffff ~32MB lower mmap space (grows up)
- 02000000-021fffff 2MB Stack space (grows down from top)
- 02200000-nnnnnnnn Executable mapping
- nnnnnnnn- brk space (grows up)
- -bfffffff upper mmap space (grows down)
-
-This is so arranged so as to make best use of the 16KB page tables and the way in which PGEs/PMEs
-are cached by the TLB handler. The lower mmap space is filled first, and then the upper mmap space
-is filled.
-
-
-===============================
-GDB-STUB MMU DEBUGGING SERVICES
-===============================
-
-The gdb-stub included in this kernel provides a number of services to aid in the debugging of MMU
-related kernel services:
-
- (*) Every time the kernel stops, certain state information is dumped into __debug_mmu. This
- variable is defined in arch/frv/kernel/gdb-stub.c. Note that the gdbinit file in this
- directory has some useful macros for dealing with this.
-
- (*) __debug_mmu.tlb[]
-
- This receives the current TLB contents. This can be viewed with the _tlb GDB macro:
-
- (gdb) _tlb
- tlb[0x00]: 01000005 00718203 01000002 00718203
- tlb[0x01]: 01004002 006d4201 01004005 006d4203
- tlb[0x02]: 01008002 006d0201 01008006 00004200
- tlb[0x03]: 0100c006 007f4202 0100c002 0064c202
- tlb[0x04]: 01110005 00774201 01110002 00774201
- tlb[0x05]: 01114005 00770201 01114002 00770201
- tlb[0x06]: 01118002 0076c201 01118005 0076c201
- ...
- tlb[0x3d]: 010f4002 00790200 001f4002 0054ca02
- tlb[0x3e]: 010f8005 0078c201 010f8002 0078c201
- tlb[0x3f]: 001fc002 0056ca01 001fc005 00538a01
-
- (*) __debug_mmu.iamr[]
- (*) __debug_mmu.damr[]
-
- These receive the current IAMR and DAMR contents. These can be viewed with the _amr
- GDB macro:
-
- (gdb) _amr
- AMRx DAMR IAMR
- ==== ===================== =====================
- amr0 : L:c0000000 P:00000cb9 : L:c0000000 P:000004b9
- amr1 : L:01070005 P:006f9203 : L:0102c005 P:006a1201
- amr2 : L:d8d00000 P:00000000 : L:d8d00000 P:00000000
- amr3 : L:d8d04000 P:00534c0d : L:00000000 P:00000000
- amr4 : L:d8d08000 P:00554c0d : L:00000000 P:00000000
- amr5 : L:d8d0c000 P:00554c0d : L:00000000 P:00000000
- amr6 : L:d8d10000 P:00000000 : L:00000000 P:00000000
- amr7 : L:d8d14000 P:00000000 : L:00000000 P:00000000
- amr8 : L:d8d18000 P:00000000
- amr9 : L:d8d1c000 P:00000000
- amr10: L:d8d20000 P:00000000
- amr11: L:e0000000 P:e0000ccd
-
- (*) The current task's page directory is bound to DAMR3.
-
- This can be viewed with the _pgd GDB macro:
-
- (gdb) _pgd
- $3 = {{pge = {{ste = {0x554001, 0x554101, 0x554201, 0x554301, 0x554401,
- 0x554501, 0x554601, 0x554701, 0x554801, 0x554901, 0x554a01,
- 0x554b01, 0x554c01, 0x554d01, 0x554e01, 0x554f01, 0x555001,
- 0x555101, 0x555201, 0x555301, 0x555401, 0x555501, 0x555601,
- 0x555701, 0x555801, 0x555901, 0x555a01, 0x555b01, 0x555c01,
- 0x555d01, 0x555e01, 0x555f01, 0x556001, 0x556101, 0x556201,
- 0x556301, 0x556401, 0x556501, 0x556601, 0x556701, 0x556801,
- 0x556901, 0x556a01, 0x556b01, 0x556c01, 0x556d01, 0x556e01,
- 0x556f01, 0x557001, 0x557101, 0x557201, 0x557301, 0x557401,
- 0x557501, 0x557601, 0x557701, 0x557801, 0x557901, 0x557a01,
- 0x557b01, 0x557c01, 0x557d01, 0x557e01, 0x557f01}}}}, {pge = {{
- ste = {0x0 <repeats 64 times>}}}} <repeats 51 times>, {pge = {{ste = {
- 0x248001, 0x248101, 0x248201, 0x248301, 0x248401, 0x248501,
- 0x248601, 0x248701, 0x248801, 0x248901, 0x248a01, 0x248b01,
- 0x248c01, 0x248d01, 0x248e01, 0x248f01, 0x249001, 0x249101,
- 0x249201, 0x249301, 0x249401, 0x249501, 0x249601, 0x249701,
- 0x249801, 0x249901, 0x249a01, 0x249b01, 0x249c01, 0x249d01,
- 0x249e01, 0x249f01, 0x24a001, 0x24a101, 0x24a201, 0x24a301,
- 0x24a401, 0x24a501, 0x24a601, 0x24a701, 0x24a801, 0x24a901,
- 0x24aa01, 0x24ab01, 0x24ac01, 0x24ad01, 0x24ae01, 0x24af01,
- 0x24b001, 0x24b101, 0x24b201, 0x24b301, 0x24b401, 0x24b501,
- 0x24b601, 0x24b701, 0x24b801, 0x24b901, 0x24ba01, 0x24bb01,
- 0x24bc01, 0x24bd01, 0x24be01, 0x24bf01}}}}, {pge = {{ste = {
- 0x0 <repeats 64 times>}}}} <repeats 11 times>}
-
- (*) The PTD last used by the instruction TLB miss handler is attached to DAMR4.
- (*) The PTD last used by the data TLB miss handler is attached to DAMR5.
-
- These can be viewed with the _ptd_i and _ptd_d GDB macros:
-
- (gdb) _ptd_d
- $5 = {{pte = 0x0} <repeats 127 times>, {pte = 0x539b01}, {
- pte = 0x0} <repeats 896 times>, {pte = 0x719303}, {pte = 0x6d5303}, {
- pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {
- pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x6a1303}, {
- pte = 0x0} <repeats 12 times>, {pte = 0x709303}, {pte = 0x0}, {pte = 0x0},
- {pte = 0x6fd303}, {pte = 0x6f9303}, {pte = 0x6f5303}, {pte = 0x0}, {
- pte = 0x6ed303}, {pte = 0x531b01}, {pte = 0x50db01}, {
- pte = 0x0} <repeats 13 times>, {pte = 0x5303}, {pte = 0x7f5303}, {
- pte = 0x509b01}, {pte = 0x505b01}, {pte = 0x7c9303}, {pte = 0x7b9303}, {
- pte = 0x7b5303}, {pte = 0x7b1303}, {pte = 0x7ad303}, {pte = 0x0}, {
- pte = 0x0}, {pte = 0x7a1303}, {pte = 0x0}, {pte = 0x795303}, {pte = 0x0}, {
- pte = 0x78d303}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {pte = 0x0}, {
- pte = 0x0}, {pte = 0x775303}, {pte = 0x771303}, {pte = 0x76d303}, {
- pte = 0x0}, {pte = 0x765303}, {pte = 0x7c5303}, {pte = 0x501b01}, {
- pte = 0x4f1b01}, {pte = 0x4edb01}, {pte = 0x0}, {pte = 0x4f9b01}, {
- pte = 0x4fdb01}, {pte = 0x0} <repeats 2992 times>}
Setting this option causes the FR-V atomic operations to be mostly
implemented out-of-line.
- See Documentation/fujitsu/frv/atomic-ops.txt for more information.
+ See Documentation/frv/atomic-ops.txt for more information.
config HIGHMEM
bool "High memory support"
andi.p gr5,#~PSR_ET,gr5
# set CCCR.CC3 to Undefined to abort atomic-modify completion inside the kernel
- # - for an explanation of how it works, see: Documentation/fujitsu/frv/atomic-ops.txt
+ # - for an explanation of how it works, see: Documentation/frv/atomic-ops.txt
andi gr25,#~0xc0,gr25
sti gr20,@(gr28,#REG_TBR)
sti gr22,@(sp,#REG_SP)
# set CCCR.CC3 to Undefined to abort atomic-modify completion inside the kernel
- # - for an explanation of how it works, see: Documentation/fujitsu/frv/atomic-ops.txt
+ # - for an explanation of how it works, see: Documentation/frv/atomic-ops.txt
movsg cccr,gr20
andi gr20,#~0xc0,gr20
movgs gr20,cccr
/* atomic-ops.S: kernel atomic operations
*
* For an explanation of how atomic ops work in this arch, see:
- * Documentation/fujitsu/frv/atomic-ops.txt
+ * Documentation/frv/atomic-ops.txt
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
/* atomic.h: atomic operation emulation for FR-V
*
* For an explanation of how atomic ops work in this arch, see:
- * Documentation/fujitsu/frv/atomic-ops.txt
+ * Documentation/frv/atomic-ops.txt
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
/* bitops.h: bit operations for the Fujitsu FR-V CPUs
*
* For an explanation of how atomic ops work in this arch, see:
- * Documentation/fujitsu/frv/atomic-ops.txt
+ * Documentation/frv/atomic-ops.txt
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* Written by David Howells (dhowells@redhat.com)
* - Derived from include/asm-i386/highmem.h
*
- * See Documentation/fujitsu/frv/mmu-layout.txt for more information.
+ * See Documentation/frv/mmu-layout.txt for more information.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
#ifdef CONFIG_MMU
-/* see Documentation/fujitsu/frv/mmu-layout.txt */
+/* see Documentation/frv/mmu-layout.txt */
#define KERNEL_LOWMEM_START __UL(0xc0000000)
#define KERNEL_LOWMEM_END __UL(0xd0000000)
#define VMALLOC_START __UL(0xd0000000)
/*
* we use 2-level page tables, folding the PMD (mid-level table) into the PGE (top-level entry)
- * [see Documentation/fujitsu/frv/mmu-layout.txt]
+ * [see Documentation/frv/mmu-layout.txt]
*
* Page Directory:
* - Size: 16KB
projects / openwrt / staging / blogic.git / commitdiff