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Commit bfd6fc05 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Add debugging check to fpu_copy() 



Also add a bit of documentation.

Reviewed-by: default avatarBorislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e102f30f

arch/x86/kernel/fpu/core.c

+10 −0
Original line number Diff line number Diff line
@@ -203,8 +203,18 @@ void fpstate_free(struct fpu *fpu) 
}

EXPORT_SYMBOL_GPL(fpstate_free);



/*

 * Copy the current task's FPU state to a new task's FPU context.

 *

 * In the 'eager' case we just save to the destination context.

 *

 * In the 'lazy' case we save to the source context, mark the FPU lazy

 * via stts() and copy the source context into the destination context.

 */

static void fpu_copy(struct task_struct *dst, struct task_struct *src)

{

	WARN_ON(src != current);



	if (use_eager_fpu()) {

		memset(&dst->thread.fpu.state->xsave, 0, xstate_size);

		__save_fpu(dst);