powerpc: Don't use thread struct for saving SRR0/1 on syscall.

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CR0 can be saved later, and CTR can also be used for saving.

Keep SRR1 in r9 and stash SRR0 in CTR, this avoids using thread_struct
in memory for that.

Saves 3 cycles (ie 1%) in null_syscall selftest on 8xx.

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/b94c3bc03bac9431fec2dadb686384c481889422.1580470483.git.christophe.leroy@c-s.fr

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Christophe Leroy 2020-01-31 11:34:55 +00:00 • committed by Michael Ellerman

parent 9e27086292

commit c06f0aff03

1 changed files with 7 additions and 9 deletions

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arch/powerpc/kernel/head_32.h

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