diff options
| author | John David Anglin <dave.anglin@bell.net> | 2013-05-20 16:42:53 +0000 |
|---|---|---|
| committer | Helge Deller <deller@gmx.de> | 2013-05-24 22:35:36 +0200 |
| commit | b63a2bbc0b9b106a93e11952ab057e2408f2eb02 (patch) | |
| tree | 28dfb7722a7c974f9872a566905b441cf7f18190 /arch/parisc/kernel | |
| parent | d0c3be806a3fe7f4abdb0f7e7287addb55e73f35 (diff) | |
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>
Diffstat (limited to 'arch/parisc/kernel')
| -rw-r--r-- | arch/parisc/kernel/entry.S | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S index ae27cb6ce19..e8f07dd2840 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 |