arm64: add abstractions for FPSIMD state manipulation

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There are two tacit assumptions in the FPSIMD handling code that will no longer
hold after the next patch that optimizes away some FPSIMD state restores:
. the FPSIMD registers of this CPU contain the userland FPSIMD state of
  task 'current';
. when switching to a task, its FPSIMD state will always be restored from
  memory.

This patch adds the following functions to abstract away from straight FPSIMD
register file saves and restores:
- fpsimd_preserve_current_state -> ensure current's FPSIMD state is saved
- fpsimd_update_current_state -> replace current's FPSIMD state

Where necessary, the signal handling and fork code are updated to use the above
wrappers instead of poking into the FPSIMD registers directly.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

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This commit is contained in:

Ard Biesheuvel 2014-02-24 15:26:27 +01:00

parent 0567f5facb

commit c51f92693c

5 changed files with 30 additions and 13 deletions

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3

arch/arm64/include/asm/fpsimd.h

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20

arch/arm64/kernel/fpsimd.c

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2

arch/arm64/kernel/process.c

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9

arch/arm64/kernel/signal.c

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9

arch/arm64/kernel/signal32.c

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