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author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2014-02-24 15:26:27 +0100 |
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committer | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2014-05-08 11:31:41 +0200 |
commit | c51f92693c35c141cf7d9b7e2fcbb81128324eb4 (patch) | |
tree | 940006e10b6aa199babdbc16da334713682174b8 /arch/arm64/kernel/signal.c | |
parent | 0567f5facbdf04806a37ef521dd0893159fde715 (diff) | |
download | linux-stable-c51f92693c35c141cf7d9b7e2fcbb81128324eb4.tar.gz linux-stable-c51f92693c35c141cf7d9b7e2fcbb81128324eb4.tar.bz2 linux-stable-c51f92693c35c141cf7d9b7e2fcbb81128324eb4.zip |
arm64: add abstractions for FPSIMD state manipulation
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>
Diffstat (limited to 'arch/arm64/kernel/signal.c')
-rw-r--r-- | arch/arm64/kernel/signal.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 890a591f75dd..06448a77ff53 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -51,7 +51,7 @@ static int preserve_fpsimd_context(struct fpsimd_context __user *ctx) int err; /* dump the hardware registers to the fpsimd_state structure */ - fpsimd_save_state(fpsimd); + fpsimd_preserve_current_state(); /* copy the FP and status/control registers */ err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs)); @@ -86,11 +86,8 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx) __get_user_error(fpsimd.fpcr, &ctx->fpcr, err); /* load the hardware registers from the fpsimd_state structure */ - if (!err) { - preempt_disable(); - fpsimd_load_state(&fpsimd); - preempt_enable(); - } + if (!err) + fpsimd_update_current_state(&fpsimd); return err ? -EFAULT : 0; } |