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Commit 2fb29fc7 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Simplify fpu__unlazy_stopped() error handling 



Now that FPU contexts are always allocated, fpu__unlazy_stopped()
cannot fail. Remove its error return and propagate the changes to
the callers.

Reviewed-by: default avatarBorislav 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: default avatarIngo Molnar <mingo@kernel.org>
parent e62bb3d8

arch/x86/kernel/fpu/core.c

+13 −35
Original line number Diff line number Diff line
@@ -296,24 +296,18 @@ EXPORT_SYMBOL_GPL(fpstate_init_curr); 
 *       the read-only case, it's not strictly necessary for

 *       read-only access to the context.

 */

static int fpu__unlazy_stopped(struct fpu *child_fpu)

static void fpu__unlazy_stopped(struct fpu *child_fpu)

{

	int ret;



	if (WARN_ON_ONCE(child_fpu == &current->thread.fpu))

		return -EINVAL;

	WARN_ON_ONCE(child_fpu == &current->thread.fpu);



	if (child_fpu->fpstate_active) {

		child_fpu->last_cpu = -1;

		return 0;

	}



	} else {

		fpstate_init(child_fpu);



		/* Safe to do for stopped child tasks: */

		child_fpu->fpstate_active = 1;



	return 0;

	}

}



/*
@@ -389,15 +383,11 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset, 
		void *kbuf, void __user *ubuf)

{

	struct fpu *fpu = &target->thread.fpu;

	int ret;



	if (!cpu_has_fxsr)

		return -ENODEV;



	ret = fpu__unlazy_stopped(fpu);

	if (ret)

		return ret;



	fpu__unlazy_stopped(fpu);

	sanitize_i387_state(target);



	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
@@ -414,10 +404,7 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset, 
	if (!cpu_has_fxsr)

		return -ENODEV;



	ret = fpu__unlazy_stopped(fpu);

	if (ret)

		return ret;



	fpu__unlazy_stopped(fpu);

	sanitize_i387_state(target);



	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
@@ -449,9 +436,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset, 
	if (!cpu_has_xsave)

		return -ENODEV;



	ret = fpu__unlazy_stopped(fpu);

	if (ret)

		return ret;

	fpu__unlazy_stopped(fpu);



	xsave = &fpu->state.xsave;
@@ -480,9 +465,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, 
	if (!cpu_has_xsave)

		return -ENODEV;



	ret = fpu__unlazy_stopped(fpu);

	if (ret)

		return ret;

	fpu__unlazy_stopped(fpu);



	xsave = &fpu->state.xsave;
@@ -643,11 +626,8 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, 
{

	struct fpu *fpu = &target->thread.fpu;

	struct user_i387_ia32_struct env;

	int ret;



	ret = fpu__unlazy_stopped(fpu);

	if (ret)

		return ret;

	fpu__unlazy_stopped(fpu);



	if (!static_cpu_has(X86_FEATURE_FPU))

		return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
@@ -677,9 +657,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, 
	struct user_i387_ia32_struct env;

	int ret;



	ret = fpu__unlazy_stopped(fpu);

	if (ret)

		return ret;

	fpu__unlazy_stopped(fpu);



	sanitize_i387_state(target);