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authorJohn David Anglin <dave.anglin@bell.net>2013-05-20 16:42:53 +0000
committerHelge Deller <deller@gmx.de>2013-05-24 22:35:36 +0200
commitb63a2bbc0b9b106a93e11952ab057e2408f2eb02 (patch)
tree28dfb7722a7c974f9872a566905b441cf7f18190
parentd0c3be806a3fe7f4abdb0f7e7287addb55e73f35 (diff)
downloadlinux-b63a2bbc0b9b106a93e11952ab057e2408f2eb02.tar.bz2
parisc: make interrupt and interruption stack allocation reentrant
The get_stack_use_cr30 and get_stack_use_r30 macros allocate a stack frame for external interrupts and interruptions requiring a stack frame. They are currently not reentrant in that they save register context before the stack is set or adjusted. I have observed a number of system crashes where there was clear evidence of stack corruption during interrupt processing, and as a result register corruption. Some interruptions can still occur during interruption processing, however external interrupts are disabled and data TLB misses don't occur for absolute accesses. So, it's not entirely clear what triggers this issue. Also, if an interruption occurs when Q=0, it is generally not possible to recover as the shadowed registers are not copied. The attached patch reworks the get_stack_use_cr30 and get_stack_use_r30 macros to allocate stack before doing register saves. The new code is a couple of instructions shorter than the old implementation. Thus, it's an improvement even if it doesn't fully resolve the stack corruption issue. Based on limited testing, it improves SMP system stability. Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de>
-rw-r--r--arch/parisc/include/asm/assembly.h1
-rw-r--r--arch/parisc/kernel/entry.S19
2 files changed, 10 insertions, 10 deletions
diff --git a/arch/parisc/include/asm/assembly.h b/arch/parisc/include/asm/assembly.h
index 89fb40005e3f..0da848232344 100644
--- a/arch/parisc/include/asm/assembly.h
+++ b/arch/parisc/include/asm/assembly.h
@@ -438,7 +438,6 @@
SAVE_SP (%sr4, PT_SR4 (\regs))
SAVE_SP (%sr5, PT_SR5 (\regs))
SAVE_SP (%sr6, PT_SR6 (\regs))
- SAVE_SP (%sr7, PT_SR7 (\regs))
SAVE_CR (%cr17, PT_IASQ0(\regs))
mtctl %r0, %cr17
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index ae27cb6ce19a..e8f07dd28401 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -65,15 +65,11 @@
rsm PSW_SM_I, %r0 /* barrier for "Relied upon Translation */
mtsp %r0, %sr4
mtsp %r0, %sr5
- mfsp %sr7, %r1
- or,= %r0,%r1,%r0 /* Only save sr7 in sr3 if sr7 != 0 */
- mtsp %r1, %sr3
+ mtsp %r0, %sr6
tovirt_r1 %r29
load32 KERNEL_PSW, %r1
rsm PSW_SM_QUIET,%r0 /* second "heavy weight" ctl op */
- mtsp %r0, %sr6
- mtsp %r0, %sr7
mtctl %r0, %cr17 /* Clear IIASQ tail */
mtctl %r0, %cr17 /* Clear IIASQ head */
mtctl %r1, %ipsw
@@ -119,17 +115,20 @@
/* we save the registers in the task struct */
+ copy %r30, %r17
mfctl %cr30, %r1
+ ldo THREAD_SZ_ALGN(%r1), %r30
+ mtsp %r0,%sr7
+ mtsp %r16,%sr3
tophys %r1,%r9
LDREG TI_TASK(%r9), %r1 /* thread_info -> task_struct */
tophys %r1,%r9
ldo TASK_REGS(%r9),%r9
- STREG %r30, PT_GR30(%r9)
+ STREG %r17,PT_GR30(%r9)
STREG %r29,PT_GR29(%r9)
STREG %r26,PT_GR26(%r9)
+ STREG %r16,PT_SR7(%r9)
copy %r9,%r29
- mfctl %cr30, %r1
- ldo THREAD_SZ_ALGN(%r1), %r30
.endm
.macro get_stack_use_r30
@@ -137,10 +136,12 @@
/* we put a struct pt_regs on the stack and save the registers there */
tophys %r30,%r9
- STREG %r30,PT_GR30(%r9)
+ copy %r30,%r1
ldo PT_SZ_ALGN(%r30),%r30
+ STREG %r1,PT_GR30(%r9)
STREG %r29,PT_GR29(%r9)
STREG %r26,PT_GR26(%r9)
+ STREG %r16,PT_SR7(%r9)
copy %r9,%r29
.endm