powerpc/32: Reorder instructions to avoid using CTR in syscall entry

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Now that we are using rfi instead of mtmsr to reactivate MMU, it is
possible to reorder instructions and avoid the need to use CTR for
stashing SRR0.

null_syscall on 8xx is reduced by 3 cycles (283 => 280 cycles).

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8fa13a59f73647e058c95fc7e1c7a98f316bd20a.1612796617.git.christophe.leroy@csgroup.eu

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Christophe Leroy 2021-02-08 15:10:23 +00:00 • committed by Michael Ellerman

parent 76249ddc27

commit 2c59e51048

1 changed files with 10 additions and 12 deletions

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arch/powerpc/kernel/head_32.h

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