powerpc: implement CONFIG_DEBUG_VIRTUAL

This patch implements CONFIG_DEBUG_VIRTUAL to warn about
incorrect use of virt_to_phys() and page_to_phys()

Below is the result of test_debug_virtual:

[    1.438746] WARNING: CPU: 0 PID: 1 at ./arch/powerpc/include/asm/io.h:808 test_debug_virtual_init+0x3c/0xd4
[    1.448156] CPU: 0 PID: 1 Comm: swapper Not tainted 4.20.0-rc5-00560-g6bfb52e23a00-dirty #532
[    1.457259] NIP:  c066c550 LR: c0650ccc CTR: c066c514
[    1.462257] REGS: c900bdb0 TRAP: 0700   Not tainted  (4.20.0-rc5-00560-g6bfb52e23a00-dirty)
[    1.471184] MSR:  00029032 <EE,ME,IR,DR,RI>  CR: 48000422  XER: 20000000
[    1.477811]
[    1.477811] GPR00: c0650ccc c900be60 c60d0000 00000000 006000c0 c9000000 00009032 c7fa0020
[    1.477811] GPR08: 00002400 00000001 09000000 00000000 c07b5d04 00000000 c00037d8 00000000
[    1.477811] GPR16: 00000000 00000000 00000000 00000000 c0760000 c0740000 00000092 c0685bb0
[    1.477811] GPR24: c065042c c068a734 c0685b8c 00000006 00000000 c0760000 c075c3c0 ffffffff
[    1.512711] NIP [c066c550] test_debug_virtual_init+0x3c/0xd4
[    1.518315] LR [c0650ccc] do_one_initcall+0x8c/0x1cc
[    1.523163] Call Trace:
[    1.525595] [c900be60] [c0567340] 0xc0567340 (unreliable)
[    1.530954] [c900be90] [c0650ccc] do_one_initcall+0x8c/0x1cc
[    1.536551] [c900bef0] [c0651000] kernel_init_freeable+0x1f4/0x2cc
[    1.542658] [c900bf30] [c00037ec] kernel_init+0x14/0x110
[    1.547913] [c900bf40] [c000e1d0] ret_from_kernel_thread+0x14/0x1c
[    1.553971] Instruction dump:
[    1.556909] 3ca50100 bfa10024 54a5000e 3fa0c076 7c0802a6 3d454000 813dc204 554893be
[    1.564566] 7d294010 7d294910 90010034 39290001 <0f090000> 7c3e0b78 955e0008 3fe0c062
[    1.572425] ---[ end trace 6f6984225b280ad6 ]---
[    1.577467] PA: 0x09000000 for VA: 0xc9000000
[    1.581799] PA: 0x061e8f50 for VA: 0xc61e8f50

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 8ea7c2c02cbf68a973b90f7099fc865c394f4d25..c446e377acd3f7a96ad989370db3255109bfaa83 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -128,6 +128,7 @@ config PPC
        #
        # Please keep this list sorted alphabetically.
        #
+       select ARCH_HAS_DEBUG_VIRTUAL
        select ARCH_HAS_DEVMEM_IS_ALLOWED
        select ARCH_HAS_DMA_SET_COHERENT_MASK
        select ARCH_HAS_ELF_RANDOMIZE

diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index e746becd9d6ff29c65ab0109fb82dd945a046f6d..7f19fbd3ba55c394a7c9fdbe102af3eb59430cd2 100644 (file)
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -29,12 +29,14 @@ extern struct pci_dev *isa_bridge_pcidev;
 
 #include <linux/device.h>
 #include <linux/compiler.h>
+#include <linux/mm.h>
 #include <asm/page.h>
 #include <asm/byteorder.h>
 #include <asm/synch.h>
 #include <asm/delay.h>
 #include <asm/mmu.h>
 #include <asm/ppc_asm.h>
+#include <asm/pgtable.h>
 
 #ifdef CONFIG_PPC64
 #include <asm/paca.h>
@@ -804,6 +806,8 @@ extern void __iounmap_at(void *ea, unsigned long size);
  */
 static inline unsigned long virt_to_phys(volatile void * address)
 {
+       WARN_ON(IS_ENABLED(CONFIG_DEBUG_VIRTUAL) && !virt_addr_valid(address));
+
        return __pa((unsigned long)address);
 }
 
@@ -827,7 +831,14 @@ static inline void * phys_to_virt(unsigned long address)
 /*
  * Change "struct page" to physical address.
  */
-#define page_to_phys(page)     ((phys_addr_t)page_to_pfn(page) << PAGE_SHIFT)
+static inline phys_addr_t page_to_phys(struct page *page)
+{
+       unsigned long pfn = page_to_pfn(page);
+
+       WARN_ON(IS_ENABLED(CONFIG_DEBUG_VIRTUAL) && !pfn_valid(pfn));
+
+       return PFN_PHYS(pfn);
+}
 
 /*
  * 32 bits still uses virt_to_bus() for it's implementation of DMA

diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 4fc77a99c9bfc6d0c5bd601c329cfce22e33d796..d67215248d822677644a6a87a9dfb8d32a236188 100644 (file)
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -143,7 +143,7 @@ __ioremap_caller(phys_addr_t addr, unsigned long size, pgprot_t prot, void *call
         * Don't allow anybody to remap normal RAM that we're using.
         * mem_init() sets high_memory so only do the check after that.
         */
-       if (slab_is_available() && (p < virt_to_phys(high_memory)) &&
+       if (slab_is_available() && p <= virt_to_phys(high_memory - 1) &&
            page_is_ram(__phys_to_pfn(p))) {
                printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n",
                       (unsigned long long)p, __builtin_return_address(0));