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Commit d0903193 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Rename sanitize_i387_state() to fpstate_sanitize_xstate() 



So the sanitize_i387_state() function has the following purpose:
on CPUs that support optimized xstate saving instructions, an
FPU fpstate might end up having partially uninitialized data.

This function initializes that data.

Note that the function name is a misnomer and confusing on two levels,
not only is it not i387 specific at all, but it is the exact opposite:
it only matters on xstate CPUs.

So rename sanitize_i387_state() and __sanitize_i387_state() to
fpstate_sanitize_xstate() and __fpstate_sanitize_xstate(),
to clearly express the purpose and usage of the function.

We'll further clean up this function in the next patch.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
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 befc61ad

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

+3 −3
Original line number Diff line number Diff line
@@ -139,13 +139,13 @@ static inline void fx_finit(struct i387_fxsave_struct *fx) 
	fx->mxcsr = MXCSR_DEFAULT;

}



extern void __sanitize_i387_state(struct task_struct *);

extern void __fpstate_sanitize_xstate(struct task_struct *);



static inline void sanitize_i387_state(struct task_struct *tsk)

static inline void fpstate_sanitize_xstate(struct task_struct *tsk)

{

	if (!use_xsaveopt())

		return;

	__sanitize_i387_state(tsk);

	__fpstate_sanitize_xstate(tsk);

}



#define user_insn(insn, output, input...)				\

arch/x86/kernel/fpu/core.c

+4 −4
Original line number Diff line number Diff line
@@ -395,7 +395,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset, 
		return -ENODEV;



	fpu__activate_stopped(fpu);

	sanitize_i387_state(target);

	fpstate_sanitize_xstate(target);



	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,

				   &fpu->state.fxsave, 0, -1);
@@ -412,7 +412,7 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset, 
		return -ENODEV;



	fpu__activate_stopped(fpu);

	sanitize_i387_state(target);

	fpstate_sanitize_xstate(target);



	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,

				 &fpu->state.fxsave, 0, -1);
@@ -644,7 +644,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, 
					   &fpu->state.fsave, 0,

					   -1);



	sanitize_i387_state(target);

	fpstate_sanitize_xstate(target);



	if (kbuf && pos == 0 && count == sizeof(env)) {

		convert_from_fxsr(kbuf, target);
@@ -666,7 +666,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, 


	fpu__activate_stopped(fpu);



	sanitize_i387_state(target);

	fpstate_sanitize_xstate(target);



	if (!static_cpu_has(X86_FEATURE_FPU))

		return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);

arch/x86/kernel/fpu/xstate.c

+2 −2
Original line number Diff line number Diff line
@@ -92,7 +92,7 @@ EXPORT_SYMBOL_GPL(cpu_has_xfeatures); 
 * if the corresponding header bit is zero. This is to ensure that user-space doesn't

 * see some stale state in the memory layout during signal handling, debugging etc.

 */

void __sanitize_i387_state(struct task_struct *tsk)

void __fpstate_sanitize_xstate(struct task_struct *tsk)

{

	struct i387_fxsave_struct *fx = &tsk->thread.fpu.state.fxsave;

	int feature_bit;
@@ -318,7 +318,7 @@ int save_xstate_sig(void __user *buf, void __user *buf_fx, int size) 
		if (ia32_fxstate)

			fpu_fxsave(&tsk->thread.fpu);

	} else {

		sanitize_i387_state(tsk);

		fpstate_sanitize_xstate(tsk);

		if (__copy_to_user(buf_fx, xsave, xstate_size))

			return -1;

	}