Commit 72ee6f87 authored Apr 27, 2015 by Ingo Molnar

x86/fpu: Simplify __save_fpu()



__save_fpu() has this pattern:

		if (unlikely(system_state == SYSTEM_BOOTING))
			xsave_state_booting(&fpu->state.xsave);
		else
			xsave_state(&fpu->state.xsave);

... but it does not actually get called during system bootup.

So remove the complication and always call xsave_state().

To make sure this assumption is correct, add a WARN_ONCE()
debug check to xsave_state().

Reviewed-by: Borislav 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: Ingo Molnar <mingo@kernel.org>

parent 32b49b3c

arch/x86/include/asm/fpu/xsave.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -133,6 +133,8 @@ static inline int xsave_state(struct xsave_struct *fx)
		u32 hmask = mask >> 32;
		int err = 0;

		WARN_ON(system_state == SYSTEM_BOOTING);

		/*
		* If xsaves is enabled, xsaves replaces xsaveopt because
		* it supports compact format and supervisor states in addition to

arch/x86/kernel/fpu/core.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -172,9 +172,6 @@ EXPORT_SYMBOL_GPL(irq_ts_restore);
		static void __save_fpu(struct fpu *fpu)
		{
		if (use_xsave()) {
		if (unlikely(system_state == SYSTEM_BOOTING))
		xsave_state_booting(&fpu->state.xsave);
		else
		xsave_state(&fpu->state.xsave);
		} else {
		fpu_fxsave(fpu);