3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: John David Anglin <dave.anglin@xxxxxxxx> 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@xxxxxxxx> Signed-off-by: Helge Deller <deller@xxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/parisc/include/asm/assembly.h | 1 - arch/parisc/kernel/entry.S | 19 ++++++++++--------- 2 files changed, 10 insertions(+), 10 deletions(-) --- 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 --- 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 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html