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authorJohn David Anglin <dave.anglin@bell.net>2013-05-20 16:42:53 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-06-27 10:38:42 -0700
commitec62e8914c5994ab7c7873b6522691b70458bfa1 (patch)
tree1270107aacd56801d3fab37deb5b2abf39ef8cf5
parent495a903504ed9a9bcfe85b60fd33d9df97f7df4c (diff)
parisc: make interrupt and interruption stack allocation reentrant
commit b63a2bbc0b9b106a93e11952ab057e2408f2eb02 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 992e8fa1b9e8..950699cfcc0d 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