powerpc: Add the ability to save FPU without giving it up

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This patch adds the ability to be able to save the FPU registers to the
thread struct without giving up (disabling the facility) next time the
process returns to userspace.

This patch optimises the thread copy path (as a result of a fork() or
clone()) so that the parent thread can return to userspace with hot
registers avoiding a possibly pointless reload of FPU register state.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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Cyril Bur 2016-02-29 17:53:49 +11:00 • committed by Michael Ellerman

parent de2a20aa72

commit 8792468da5

3 changed files with 17 additions and 19 deletions

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3

arch/powerpc/include/asm/switch_to.h

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21

arch/powerpc/kernel/fpu.S

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12

arch/powerpc/kernel/process.c

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