+++ /dev/null
-From f9b4e05597e636a550af8392e80b15f79d9f9e11 Mon Sep 17 00:00:00 2001
-From: Florian Fainelli <florian@openwrt.org>
-Date: Thu, 14 Mar 2013 14:07:20 +0100
-Subject: [PATCH] MIPS: fix code generation for non-DSP capable CPUs
-
-Commit 32a7ede (MIPS: dsp: Add assembler support for DSP ASEs) has
-enabled the use of DSP ASE specific instructions such as rddsp and wrdsp
-under the idea that all code path that will make use of these two
-instructions are properly checking for cpu_has_dsp to ensure that the
-particular CPU we are running on *actually* supports DSP ASE.
-
-This commit actually causes the following oops on QEMU Malta emulating a
-MIPS 24Kc without the DSP ASE implemented:
-
-[ 7.960000] Reserved instruction in kernel
-[ 7.960000] Cpu 0
-[ 7.960000] $ 0 : 00000000 00000000 00000014 00000005
-[ 7.960000] $ 4 : 8fc2de48 00000001 00000000 8f59ddb0
-[ 7.960000] $ 8 : 8f5ceec4 00000018 00000c00 00800000
-[ 7.960000] $12 : 00000100 00000200 00000000 00457b84
-[ 7.960000] $16 : 00000000 8fc2ba78 8f4ec980 00000001
-[ 7.960000] $20 : 80418f90 00000000 00000000 000002dd
-[ 7.960000] $24 : 0000009c 7730d7b8
-[ 7.960000] $28 : 8f59c000 8f59dd38 00000001 80104248
-[ 7.960000] Hi : 0000001d
-[ 7.960000] Lo : 0000000b
-[ 7.960000] epc : 801041ec thread_saved_pc+0x2c/0x38
-[ 7.960000] Not tainted
-[ 7.960000] ra : 80104248 get_wchan+0x48/0xac
-[ 7.960000] Status: 1000b703 KERNEL EXL IE
-[ 7.960000] Cause : 10800028
-[ 7.960000] PrId : 00019300 (MIPS 24Kc)
-[ 7.960000] Modules linked in:
-[ 7.960000] Process killall (pid: 1574, threadinfo=8f59c000,
-task=8fd14558, tls=773aa440)
-[ 7.960000] Stack : 8fc2ba78 8012b008 0000000c 0000001d 00000000
-00000000 8f58a380
- 8f58a380 8fc2ba78 80202668 8f59de78 8f468600 8f59de28
-801b2a3c 8f59df00 8f98ba20 74696e69
- 8f468600 8f59de28 801b7308 0081c007 00000000 00000000
-00000000 00000000 00000000 00000000
- 00000000 8fc2bbb4 00000001 0000001d 0000000b 77f038cc
-7fe80648 ffffffff ffffffff 00000000
- 00000001 0016e000 00000000 ...
-[ 7.960000] Call Trace:
-[ 7.960000] [<801041ec>] thread_saved_pc+0x2c/0x38
-[ 7.960000] [<80104248>] get_wchan+0x48/0xac
-
-The disassembly of thread_saved_pc points to the following:
-000006d0 <thread_saved_pc>:
- 6d0: 8c820208 lw v0,520(a0)
- 6d4: 3c030000 lui v1,0x0
- 6d8: 24630000 addiu v1,v1,0
- 6dc: 10430008 beq v0,v1,700 <thread_saved_pc+0x30>
- 6e0: 00000000 nop
- 6e4: 3c020000 lui v0,0x0
- 6e8: 8c43000c lw v1,12(v0)
- 6ec: 04620004 bltzl v1,700 <thread_saved_pc+0x30>
- 6f0: 00001021 move v0,zero
- 6f4: 8c840200 lw a0,512(a0)
- 6f8: 00031080 sll v0,v1,0x2
- 6fc: 7c44100a lwx v0,a0(v0) <------------
- 700: 03e00008 jr ra
- 704: 00000000 nop
-
-If we specifically disable -mdsp/-mdspr2 for arch/mips/kernel/process.o,
-we get the following (non-crashing) assembly:
-
-00000708 <thread_saved_pc>:
- 708: 8c820208 lw v0,520(a0)
- 70c: 3c030000 lui v1,0x0
- 710: 24630000 addiu v1,v1,0
- 714: 10430009 beq v0,v1,73c <thread_saved_pc+0x34>
- 718: 00000000 nop
- 71c: 3c020000 lui v0,0x0
- 720: 8c42000c lw v0,12(v0)
- 724: 04420005 bltzl v0,73c <thread_saved_pc+0x34>
- 728: 00001021 move v0,zero
- 72c: 8c830200 lw v1,512(a0)
- 730: 00021080 sll v0,v0,0x2
- 734: 00431021 addu v0,v0,v1
- 738: 8c420000 lw v0,0(v0)
- 73c: 03e00008 jr ra
- 740: 00000000 nop
-
-The specific line that leads a different assembly being produced is:
-
-unsigned long thread_saved_pc(struct task_struct *tsk)
-...
- return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; <---
-
-The problem here is that the compiler was given the right to use DSP
-instructions with the -mdsp / -mdspr2 command-line switches and
-performed some optimization for us and used DSP ASE instructions where
-we are not checking that the running CPU actually supports DSP ASE.
-
-This patch fixes the issue by partially reverting commit 32a7ede for
-arch/mips/kernel/Makefile in order to remove the -mdsp / -mdspr2
-compiler command-line switches such that we are now guaranteed that the
-compiler will not optimize using DSP ASE reserved instructions. We also
-need to fixup the rddsp/wrdsp and m{t,h}{hi,lo}{0,1,2,3} macros in
-arch/mips/include/asm/mipsregs.h to tell the assembler that we are going
-to explicitely use DSP ASE reserved instructions.
-
-Signed-off-by: Florian Fainelli <florian@openwrt.org>
----
-Ralf, John,
-
-This should be part of your 3.9-rc3 pull request if I may ;)
-
- arch/mips/include/asm/mipsregs.h | 209 ++++++++++++++++++++++++++++++++++----
- arch/mips/kernel/Makefile | 14 ---
- 2 files changed, 190 insertions(+), 33 deletions(-)
-
---- a/arch/mips/include/asm/mipsregs.h
-+++ b/arch/mips/include/asm/mipsregs.h
-@@ -1166,7 +1166,10 @@ do { \
- unsigned int __dspctl; \
- \
- __asm__ __volatile__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
- " rddsp %0, %x1 \n" \
-+ " .set pop \n" \
- : "=r" (__dspctl) \
- : "i" (mask)); \
- __dspctl; \
-@@ -1175,30 +1178,198 @@ do { \
- #define wrdsp(val, mask) \
- do { \
- __asm__ __volatile__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
- " wrdsp %0, %x1 \n" \
-+ " .set pop \n" \
- : \
- : "r" (val), "i" (mask)); \
- } while (0)
-
--#define mflo0() ({ long mflo0; __asm__("mflo %0, $ac0" : "=r" (mflo0)); mflo0;})
--#define mflo1() ({ long mflo1; __asm__("mflo %0, $ac1" : "=r" (mflo1)); mflo1;})
--#define mflo2() ({ long mflo2; __asm__("mflo %0, $ac2" : "=r" (mflo2)); mflo2;})
--#define mflo3() ({ long mflo3; __asm__("mflo %0, $ac3" : "=r" (mflo3)); mflo3;})
--
--#define mfhi0() ({ long mfhi0; __asm__("mfhi %0, $ac0" : "=r" (mfhi0)); mfhi0;})
--#define mfhi1() ({ long mfhi1; __asm__("mfhi %0, $ac1" : "=r" (mfhi1)); mfhi1;})
--#define mfhi2() ({ long mfhi2; __asm__("mfhi %0, $ac2" : "=r" (mfhi2)); mfhi2;})
--#define mfhi3() ({ long mfhi3; __asm__("mfhi %0, $ac3" : "=r" (mfhi3)); mfhi3;})
--
--#define mtlo0(x) __asm__("mtlo %0, $ac0" ::"r" (x))
--#define mtlo1(x) __asm__("mtlo %0, $ac1" ::"r" (x))
--#define mtlo2(x) __asm__("mtlo %0, $ac2" ::"r" (x))
--#define mtlo3(x) __asm__("mtlo %0, $ac3" ::"r" (x))
--
--#define mthi0(x) __asm__("mthi %0, $ac0" ::"r" (x))
--#define mthi1(x) __asm__("mthi %0, $ac1" ::"r" (x))
--#define mthi2(x) __asm__("mthi %0, $ac2" ::"r" (x))
--#define mthi3(x) __asm__("mthi %0, $ac3" ::"r" (x))
-+#define mflo0() \
-+({ \
-+ long mflo0; \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mflo %0, $ac0 \n" \
-+ " .set pop \n" \
-+ : "=r" (mflo0)); \
-+ mflo0; \
-+})
-+
-+#define mflo1() \
-+({ \
-+ long mflo1; \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mflo %0, $ac1 \n" \
-+ " .set pop \n" \
-+ : "=r" (mflo1)); \
-+ mflo1; \
-+})
-+
-+#define mflo2() \
-+({ \
-+ long mflo2; \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mflo %0, $ac2 \n" \
-+ " .set pop \n" \
-+ : "=r" (mflo2)); \
-+ mflo2; \
-+})
-+
-+#define mflo3() \
-+({ \
-+ long mflo3; \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mflo %0, $ac3 \n" \
-+ " .set pop \n" \
-+ : "=r" (mflo3)); \
-+ mflo3; \
-+})
-+
-+#define mfhi0() \
-+({ \
-+ long mfhi0; \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mfhi %0, $ac0 \n" \
-+ " .set pop \n" \
-+ : "=r" (mfhi0)); \
-+ mfhi0; \
-+})
-+
-+#define mfhi1() \
-+({ \
-+ long mfhi1; \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mfhi %0, $ac1 \n" \
-+ " .set pop \n" \
-+ : "=r" (mfhi1)); \
-+ mfhi1; \
-+})
-+
-+#define mfhi2() \
-+({ \
-+ long mfhi2; \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mfhi %0, $ac2 \n" \
-+ " .set pop \n" \
-+ : "=r" (mfhi2)); \
-+ mfhi2; \
-+})
-+
-+#define mfhi3() \
-+({ \
-+ long mfhi3; \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mfhi %0, $ac3 \n" \
-+ " .set pop \n" \
-+ : "=r" (mfhi3)); \
-+ mfhi3; \
-+})
-+
-+
-+#define mtlo0(x) \
-+({ \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mtlo %0, $ac0 \n" \
-+ " .set pop \n" \
-+ : \
-+ : "r" (x)); \
-+})
-+
-+#define mtlo1(x) \
-+({ \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mtlo %0, $ac1 \n" \
-+ " .set pop \n" \
-+ : \
-+ : "r" (x)); \
-+})
-+
-+#define mtlo2(x) \
-+({ \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mtlo %0, $ac2 \n" \
-+ " .set pop \n" \
-+ : \
-+ : "r" (x)); \
-+})
-+
-+#define mtlo3(x) \
-+({ \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mtlo %0, $ac3 \n" \
-+ " .set pop \n" \
-+ : \
-+ : "r" (x)); \
-+})
-+
-+#define mthi0(x) \
-+({ \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mthi %0, $ac0 \n" \
-+ " .set pop \n" \
-+ : \
-+ : "r" (x)); \
-+})
-+
-+#define mthi1(x) \
-+({ \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mthi %0, $ac1 \n" \
-+ " .set pop \n" \
-+ : \
-+ : "r" (x)); \
-+})
-+
-+#define mthi2(x) \
-+({ \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mthi %0, $ac2 \n" \
-+ " .set pop \n" \
-+ : \
-+ : "r" (x)); \
-+})
-+
-+#define mthi3(x) \
-+({ \
-+ __asm__( \
-+ " .set push \n" \
-+ " .set dsp \n" \
-+ " mthi %0, $ac3 \n" \
-+ " .set pop \n" \
-+ : \
-+ : "r" (x)); \
-+})
-
- #else
-
---- a/arch/mips/kernel/Makefile
-+++ b/arch/mips/kernel/Makefile
-@@ -109,20 +109,6 @@ obj-$(CONFIG_JUMP_LABEL) += jump_label.o
- ifeq ($(CONFIG_CPU_MIPSR2), y)
- CFLAGS_DSP = -DHAVE_AS_DSP
-
--#
--# Check if assembler supports DSP ASE
--#
--ifeq ($(call cc-option-yn,-mdsp), y)
--CFLAGS_DSP += -mdsp
--endif
--
--#
--# Check if assembler supports DSP ASE Rev2
--#
--ifeq ($(call cc-option-yn,-mdspr2), y)
--CFLAGS_DSP += -mdspr2
--endif
--
- CFLAGS_signal.o = $(CFLAGS_DSP)
- CFLAGS_signal32.o = $(CFLAGS_DSP)
- CFLAGS_process.o = $(CFLAGS_DSP)
projects / openwrt / staging / chunkeey.git / commitdiff