diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 39 |
1 files changed, 21 insertions, 18 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 3e57a00b8cb..ba3aeb4bc06 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -206,40 +206,43 @@ reenable_mmu: /* re-enable mmu so we can */ andi. r10,r10,MSR_EE /* Did EE change? */ beq 1f - /* Save handler and return address into the 2 unused words - * of the STACK_FRAME_OVERHEAD (sneak sneak sneak). Everything - * else can be recovered from the pt_regs except r3 which for - * normal interrupts has been set to pt_regs and for syscalls - * is an argument, so we temporarily use ORIG_GPR3 to save it - */ - stw r9,8(r1) - stw r11,12(r1) - stw r3,ORIG_GPR3(r1) /* * The trace_hardirqs_off will use CALLER_ADDR0 and CALLER_ADDR1. * If from user mode there is only one stack frame on the stack, and * accessing CALLER_ADDR1 will cause oops. So we need create a dummy * stack frame to make trace_hardirqs_off happy. + * + * This is handy because we also need to save a bunch of GPRs, + * r3 can be different from GPR3(r1) at this point, r9 and r11 + * contains the old MSR and handler address respectively, + * r4 & r5 can contain page fault arguments that need to be passed + * along as well. r12, CCR, CTR, XER etc... are left clobbered as + * they aren't useful past this point (aren't syscall arguments), + * the rest is restored from the exception frame. */ + stwu r1,-32(r1) + stw r9,8(r1) + stw r11,12(r1) + stw r3,16(r1) + stw r4,20(r1) + stw r5,24(r1) andi. r12,r12,MSR_PR - beq 11f - stwu r1,-16(r1) + b 11f bl trace_hardirqs_off - addi r1,r1,16 b 12f - 11: bl trace_hardirqs_off 12: + lwz r5,24(r1) + lwz r4,20(r1) + lwz r3,16(r1) + lwz r11,12(r1) + lwz r9,8(r1) + addi r1,r1,32 lwz r0,GPR0(r1) - lwz r3,ORIG_GPR3(r1) - lwz r4,GPR4(r1) - lwz r5,GPR5(r1) lwz r6,GPR6(r1) lwz r7,GPR7(r1) lwz r8,GPR8(r1) - lwz r9,8(r1) - lwz r11,12(r1) 1: mtctr r11 mtlr r9 bctr /* jump to handler */ |