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arm64: fpsimd: Abstract out binding of task's fpsimd context to the cpu. 

There is currently some duplicate logic to associate current's
FPSIMD context with the cpu when loading FPSIMD state into the cpu
regs.

Subsequent patches will update that logic, so in order to ensure it
only needs to be done in one place, this patch factors the relevant
code out into a new function fpsimd_bind_to_cpu().

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Dave Martin 2017-12-06 16:45:46 +00:00 committed by Will Deacon
parent 071b6d4a5d
commit 8884b7bd7e
1 changed files with 15 additions and 10 deletions
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25
arch/arm64/kernel/fpsimd.c
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@ -991,6 +991,18 @@ void fpsimd_signal_preserve_current_state(void)
sve_to_fpsimd(current);
}
/*
* Associate current's FPSIMD context with this cpu
* Preemption must be disabled when calling this function.
*/
static void fpsimd_bind_to_cpu(void)
{
struct fpsimd_state *st = &current->thread.fpsimd_state;
__this_cpu_write(fpsimd_last_state, st);
st->cpu = smp_processor_id();
}
/*
* Load the userland FPSIMD state of 'current' from memory, but only if the
* FPSIMD state already held in the registers is /not/ the most recent FPSIMD
@ -1004,11 +1016,8 @@ void fpsimd_restore_current_state(void)
local_bh_disable();
if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
struct fpsimd_state *st = &current->thread.fpsimd_state;
task_fpsimd_load();
__this_cpu_write(fpsimd_last_state, st);
st->cpu = smp_processor_id();
fpsimd_bind_to_cpu();
}
local_bh_enable();
@ -1032,12 +1041,8 @@ void fpsimd_update_current_state(struct fpsimd_state *state)
task_fpsimd_load();
if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
struct fpsimd_state *st = &current->thread.fpsimd_state;
__this_cpu_write(fpsimd_last_state, st);
st->cpu = smp_processor_id();
}
if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE))
fpsimd_bind_to_cpu();
local_bh_enable();
}