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arm64: fix possible invalid FPSIMD initialization state

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If context switching happens during executing fpsimd_flush_thread(),
stale value in FPSIMD registers will be saved into current thread's
fpsimd_state by fpsimd_thread_switch(). That may cause invalid
initialization state for the new process, so disable preemption
when executing fpsimd_flush_thread().

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Jiang Liu 2013-09-27 09:04:41 +01:00 committed by Catalin Marinas
parent fc18047c73
commit 6db83cea1c
1 changed files with 2 additions and 0 deletions
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2
arch/arm64/kernel/fpsimd.c
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@ -80,8 +80,10 @@ void fpsimd_thread_switch(struct task_struct *next)
void fpsimd_flush_thread(void) void fpsimd_flush_thread(void)
{ {
preempt_disable();
memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state)); memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
fpsimd_load_state(&current->thread.fpsimd_state); fpsimd_load_state(&current->thread.fpsimd_state);
preempt_enable();
} }
#ifdef CONFIG_KERNEL_MODE_NEON #ifdef CONFIG_KERNEL_MODE_NEON