[PATCH 144/208] x86/fpu: Eliminate __save_fpu()

From: Ingo Molnar
Date: Tue May 05 2015 - 13:54:06 EST


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@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/fpu/core.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index a0e2b65745da..478e002ab122 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -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);
--
2.1.0

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