Commit 3f7f7563 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
Browse files

x86/fpu: Use copy_xstate_to_uabi_buf() in fpregs_get() 



Use the new functionality of copy_xstate_to_uabi_buf() to retrieve the
FX state when XSAVE* is in use. This avoids to overwrite the FPU state
buffer with fpstate_sanitize_xstate() which is error prone and duplicated
code.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.014441775@linutronix.de
parent adc997b3

arch/x86/kernel/fpu/regset.c

+20 −10
Original line number Original line Diff line number Diff line
@@ -210,10 +210,10 @@ static inline u32 twd_fxsr_to_i387(struct fxregs_state *fxsave) 
 * FXSR floating point environment conversions.

 * FXSR floating point environment conversions.

 */

 */





void

static void __convert_from_fxsr(struct user_i387_ia32_struct *env,

convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk)

				struct task_struct *tsk,

				struct fxregs_state *fxsave)

{

{

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

	struct _fpreg *to = (struct _fpreg *) &env->st_space[0];

	struct _fpreg *to = (struct _fpreg *) &env->st_space[0];

	struct _fpxreg *from = (struct _fpxreg *) &fxsave->st_space[0];

	struct _fpxreg *from = (struct _fpxreg *) &fxsave->st_space[0];

	int i;

	int i;
@@ -247,6 +247,12 @@ convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk) 
		memcpy(&to[i], &from[i], sizeof(to[0]));

		memcpy(&to[i], &from[i], sizeof(to[0]));

}

}





void

convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk)

{

	__convert_from_fxsr(env, tsk, &tsk->thread.fpu.state.fxsave);

}



void convert_to_fxsr(struct fxregs_state *fxsave,

void convert_to_fxsr(struct fxregs_state *fxsave,

		     const struct user_i387_ia32_struct *env)

		     const struct user_i387_ia32_struct *env)
@@ -279,25 +285,29 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, 
{

{

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

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

	struct user_i387_ia32_struct env;

	struct user_i387_ia32_struct env;

	struct fxregs_state fxsave, *fx;





	fpu__prepare_read(fpu);

	fpu__prepare_read(fpu);





	if (!boot_cpu_has(X86_FEATURE_FPU))

	if (!cpu_feature_enabled(X86_FEATURE_FPU))

		return fpregs_soft_get(target, regset, to);

		return fpregs_soft_get(target, regset, to);





	if (!boot_cpu_has(X86_FEATURE_FXSR)) {

	if (!cpu_feature_enabled(X86_FEATURE_FXSR)) {

		return membuf_write(&to, &fpu->state.fsave,

		return membuf_write(&to, &fpu->state.fsave,

				    sizeof(struct fregs_state));

				    sizeof(struct fregs_state));

	}

	}





	fpstate_sanitize_xstate(fpu);

	if (use_xsave()) {

		struct membuf mb = { .p = &fxsave, .left = sizeof(fxsave) };





	if (to.left == sizeof(env)) {

		/* Handle init state optimized xstate correctly */

		convert_from_fxsr(to.p, target);

		copy_xstate_to_uabi_buf(mb, &fpu->state.xsave, XSTATE_COPY_FP);

		return 0;

		fx = &fxsave;

	} else {

		fx = &fpu->state.fxsave;

	}

	}





	convert_from_fxsr(&env, target);

	__convert_from_fxsr(&env, target, fx);

	return membuf_write(&to, &env, sizeof(env));

	return membuf_write(&to, &env, sizeof(env));

}

}