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Commit 6db83cea authored by Jiang Liu's avatar Jiang Liu Committed by Catalin Marinas
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arm64: fix possible invalid FPSIMD initialization state 



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: default avatarJiang Liu <jiang.liu@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent fc18047c

arch/arm64/kernel/fpsimd.c

+2 −0
Original line number Diff line number Diff line
@@ -80,8 +80,10 @@ void fpsimd_thread_switch(struct task_struct *next) 


void fpsimd_flush_thread(void)

{

	preempt_disable();

	memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));

	fpsimd_load_state(&current->thread.fpsimd_state);

	preempt_enable();

}



#ifdef CONFIG_KERNEL_MODE_NEON