Patchwork [04/22] x86/fpu: Always init the `state' in fpu__clear()

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Submitter Sebastian Andrzej Siewior
Date Jan. 9, 2019, 11:47 a.m.
Message ID <20190109114744.10936-5-bigeasy@linutronix.de>
Download mbox | patch
Permalink /patch/695723/
State New
Headers show

Comments

Sebastian Andrzej Siewior - Jan. 9, 2019, 11:47 a.m.
fpu__clear() only initializes the `state' if the FPU is present. This
initialisation is also required for the FPU-less system and takes place
math_emulate(). Since fpu__initialize() only performs the initialization
if ->initialized is zero it does not matter that it is invoked each time
an opcode is emulated. It makes the removal of ->initialized easier if
the struct is also initialized in FPU-less case at the same time.

Move fpu__initialize() before the FPU check so it is also performed in
FPU-less case.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/x86/include/asm/fpu/internal.h | 1 -
 arch/x86/kernel/fpu/core.c          | 5 ++---
 arch/x86/math-emu/fpu_entry.c       | 3 ---
 3 files changed, 2 insertions(+), 7 deletions(-)
Borislav Petkov - Jan. 14, 2019, 7:32 p.m.
On Wed, Jan 09, 2019 at 12:47:26PM +0100, Sebastian Andrzej Siewior wrote:
> fpu__clear() only initializes the `state' if the FPU is present. This
> initialisation is also required for the FPU-less system and takes place

"in math_emulate()."

> math_emulate(). Since fpu__initialize() only performs the initialization
> if ->initialized is zero it does not matter that it is invoked each time
> an opcode is emulated. It makes the removal of ->initialized easier if
> the struct is also initialized in FPU-less case at the same time.

				in the

> 
> Move fpu__initialize() before the FPU check so it is also performed in
> FPU-less case.

in the...

> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>  arch/x86/include/asm/fpu/internal.h | 1 -
>  arch/x86/kernel/fpu/core.c          | 5 ++---
>  arch/x86/math-emu/fpu_entry.c       | 3 ---
>  3 files changed, 2 insertions(+), 7 deletions(-)

With that fixed:

Reviewed-by: Borislav Petkov <bp@suse.de>

Patch

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 67675d023d4f8..9f0b3ff8c9b7b 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -24,7 +24,6 @@ 
 /*
  * High level FPU state handling functions:
  */
-extern void fpu__initialize(struct fpu *fpu);
 extern void fpu__prepare_read(struct fpu *fpu);
 extern void fpu__prepare_write(struct fpu *fpu);
 extern void fpu__save(struct fpu *fpu);
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 1940319268aef..e43296854e379 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -223,7 +223,7 @@  int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
  * Activate the current task's in-memory FPU context,
  * if it has not been used before:
  */
-void fpu__initialize(struct fpu *fpu)
+static void fpu__initialize(struct fpu *fpu)
 {
 	WARN_ON_FPU(fpu != &current->thread.fpu);
 
@@ -236,7 +236,6 @@  void fpu__initialize(struct fpu *fpu)
 		fpu->initialized = 1;
 	}
 }
-EXPORT_SYMBOL_GPL(fpu__initialize);
 
 /*
  * This function must be called before we read a task's fpstate.
@@ -365,8 +364,8 @@  void fpu__clear(struct fpu *fpu)
 	/*
 	 * Make sure fpstate is cleared and initialized.
 	 */
+	fpu__initialize(fpu);
 	if (static_cpu_has(X86_FEATURE_FPU)) {
-		fpu__initialize(fpu);
 		user_fpu_begin();
 		copy_init_fpstate_to_fpregs();
 	}
diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index 9e2ba7e667f61..a873da6b46d6b 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -113,9 +113,6 @@  void math_emulate(struct math_emu_info *info)
 	unsigned long code_base = 0;
 	unsigned long code_limit = 0;	/* Initialized to stop compiler warnings */
 	struct desc_struct code_descriptor;
-	struct fpu *fpu = &current->thread.fpu;
-
-	fpu__initialize(fpu);
 
 #ifdef RE_ENTRANT_CHECKING
 	if (emulating) {