Commit 9f876d67 authored Apr 27, 2015 by Ingo Molnar

x86/fpu: Eliminate __save_fpu()



The current implementation of __save_fpu():

	if (use_xsave()) {
		xsave_state(&fpu->state.xsave);
	} else {
		fpu_fxsave(fpu);
	}

Is actually a simplified version of copy_fpregs_to_fpstate(),
if use_eager_fpu() is true.

But all call sites of __save_fpu() call it only it when use_eager_fpu()
is true.

So we can eliminate __save_fpu() altogether and use the standard
copy_fpregs_to_fpstate() function. This cleans up the code
by making it use fewer variants of FPU register saving.

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 72ee6f87

arch/x86/kernel/fpu/core.c

+2 −11

Original line number	Diff line number	Diff line
		@@ -169,15 +169,6 @@ void irq_ts_restore(int TS_state)
		}
		EXPORT_SYMBOL_GPL(irq_ts_restore);

		static void __save_fpu(struct fpu *fpu)
		{
		if (use_xsave()) {
		xsave_state(&fpu->state.xsave);
		} else {
		fpu_fxsave(fpu);
		}
		}

		/*
		* Save the FPU state (initialize it if necessary):
		*
		@@ -190,7 +181,7 @@ void fpu__save(struct fpu *fpu)
		preempt_disable();
		if (fpu->fpregs_active) {
		if (use_eager_fpu()) {
		__save_fpu(fpu);
		copy_fpregs_to_fpstate(fpu);
		} else {
		copy_fpregs_to_fpstate(fpu);
		fpregs_deactivate(fpu);
		@@ -235,7 +226,7 @@ static void fpu_copy(struct fpu dst_fpu, struct fpu src_fpu)

		if (use_eager_fpu()) {
		memset(&dst_fpu->state.xsave, 0, xstate_size);
		__save_fpu(dst_fpu);
		copy_fpregs_to_fpstate(dst_fpu);
		} else {
		fpu__save(src_fpu);
		memcpy(&dst_fpu->state, &src_fpu->state, xstate_size);

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