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arm64: kernel thread don't need to save fpsimd context. 

kernel thread's default fpsimd state is zero. When fork a thread, if parent is kernel thread,
 and save hardware context to parent's fpsimd state, but this hardware context is user
process's context, because kernel thread don't use fpsimd, it will not introduce issue,
it add a little cost.

Signed-off-by: Janet Liu <janet.liu@spreadtrum.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Janet Liu 2015-06-11 12:04:32 +08:00 committed by Catalin Marinas
parent 04d7e098f5
commit 6eb6c80187
1 changed files with 2 additions and 1 deletions
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3
arch/arm64/kernel/process.c
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@ -233,7 +233,8 @@ void release_thread(struct task_struct *dead_task)
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
fpsimd_preserve_current_state();
if (current->mm)
fpsimd_preserve_current_state();
*dst = *src;
return 0;
}