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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2019-04-30 12:39:05 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-05-03 01:20:28 +1000 |
| commit | d1865e71cdc9b75b6a6716a2983eb5d6004cfca9 (patch) | |
| tree | b56eef5869bae0012b62383694e17007ce8c804c /arch/powerpc | |
| parent | 38b4564cf042ad3f5333692687023803c1ab1112 (diff) | |
| download | linux-d1865e71cdc9b75b6a6716a2983eb5d6004cfca9.tar.bz2 | |
powerpc/32: Don't add dummy frames when calling trace_hardirqs_on/off
No need to add dummy frames when calling trace_hardirqs_on or
trace_hardirqs_off. GCC properly handles empty stacks.
In addition, powerpc doesn't set CONFIG_FRAME_POINTER, therefore
__builtin_return_address(1..) returns NULL at all time. So the
dummy frames are definitely unneeded here.
In the meantime, avoid reading memory for loading r1 with a value
we already know.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/entry_32.S | 16 |
1 files changed, 2 insertions, 14 deletions
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index e65c3e70c648..235a01d34b6d 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -243,12 +243,7 @@ transfer_to_handler_cont: reenable_mmu: /* - * 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, + * We 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 @@ -950,18 +945,11 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_47x) */ andi. r10,r9,MSR_EE beq 1f - /* - * Since the ftrace irqsoff latency trace checks CALLER_ADDR1, - * which is the stack frame here, we need to force a stack frame - * in case we came from user space. - */ stwu r1,-32(r1) mflr r0 stw r0,4(r1) - stwu r1,-32(r1) bl trace_hardirqs_on - lwz r1,0(r1) - lwz r1,0(r1) + addi r1, r1, 32 lwz r9,_MSR(r1) 1: #endif /* CONFIG_TRACE_IRQFLAGS */ |