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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 b86fb88855 ("powerpc/32: implement fast entry for
syscalls on non BOOKE") and commit 1a4b739bbb ("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
* 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.
* along as well. r0, r6-r8, r12, CCR, CTR, XER etc... are left
* clobbered as they aren't useful past this point.
*/
stwu r1,-32(r1)
@ -262,16 +261,12 @@ reenable_mmu:
* lockdep
*/
1: bl trace_hardirqs_off
2: lwz r5,24(r1)
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 r6,GPR6(r1)
lwz r7,GPR7(r1)
lwz r8,GPR8(r1)
mtctr r11
mtlr r9
bctr /* jump to handler */