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powerpc/32: Clarify interrupt restores with REST_GPR macro in entry_32.S
authorRohan McLure <rmclure@linux.ibm.com>
Wed, 21 Sep 2022 06:55:45 +0000 (16:55 +1000)
committerMichael Ellerman <mpe@ellerman.id.au>
Mon, 26 Sep 2022 13:00:15 +0000 (23:00 +1000)
commit15ba74502ccfd0b34dad0ea022093ccc66b334d6
treee97ea30022d86c1cd880c82a2f0392a2a68f1394
parent2b1dac4b5f97ea88fb01dfcab7fc24500b5dea95
powerpc/32: Clarify interrupt restores with REST_GPR macro in entry_32.S

Restoring the register state of the interrupted thread involves issuing
a large number of predictable loads to the kernel stack frame. Issue the
REST_GPR{,S} macros to clearly signal when this is happening, and bunch
together restores at the end of the interrupt handler where the saved
value is not consumed earlier in the handler code.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reported-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220921065605.1051927-6-rmclure@linux.ibm.com
arch/powerpc/kernel/entry_32.S