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powerpc/32: don't restore r0, r6-r8 on exception entry path after trace_hardirqs_off()

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Since commit b86fb88855ea ("powerpc/32: implement fast entry for
syscalls on non BOOKE") and commit 1a4b739bbb4f ("powerpc/32:
implement fast entry for syscalls on BOOKE"), syscalls don't
use the exception entry path anymore. It is therefore pointless
to restore r0 and r6-r8 after calling trace_hardirqs_off().

In the meantime, drop the '2:' label which is unused and misleading.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d2c6dc65d27e83964eb05f16a126161ab6455eea.1578388585.git.christophe.leroy@c-s.fr
This commit is contained in:
Christophe Leroy 2020-01-07 09:16:40 +00:00 committed by Michael Ellerman
parent e1347a020b
commit 05642cf728
1 changed files with 3 additions and 8 deletions
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11
arch/powerpc/kernel/entry_32.S
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@ -246,9 +246,8 @@ reenable_mmu:
* r3 can be different from GPR3(r1) at this point, r9 and r11 * r3 can be different from GPR3(r1) at this point, r9 and r11
* contains the old MSR and handler address respectively, * contains the old MSR and handler address respectively,
* r4 & r5 can contain page fault arguments that need to be passed * r4 & r5 can contain page fault arguments that need to be passed
* along as well. r12, CCR, CTR, XER etc... are left clobbered as * along as well. r0, r6-r8, r12, CCR, CTR, XER etc... are left
* they aren't useful past this point (aren't syscall arguments), * clobbered as they aren't useful past this point.
* the rest is restored from the exception frame.
*/ */
stwu r1,-32(r1) stwu r1,-32(r1)
@ -262,16 +261,12 @@ reenable_mmu:
* lockdep * lockdep
*/ */
1: bl trace_hardirqs_off 1: bl trace_hardirqs_off
2: lwz r5,24(r1) lwz r5,24(r1)
lwz r4,20(r1) lwz r4,20(r1)
lwz r3,16(r1) lwz r3,16(r1)
lwz r11,12(r1) lwz r11,12(r1)
lwz r9,8(r1) lwz r9,8(r1)
addi r1,r1,32 addi r1,r1,32
lwz r0,GPR0(r1)
lwz r6,GPR6(r1)
lwz r7,GPR7(r1)
lwz r8,GPR8(r1)
mtctr r11 mtctr r11
mtlr r9 mtlr r9
bctr /* jump to handler */ bctr /* jump to handler */