Commit 5a32fac8 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
Browse files

x86/fpu/regset: Move fpu__read_begin() into regset 



The function can only be used from the regset get() callbacks safely. So
there is no reason to have it globally exposed.

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/20210623121453.234942936@linutronix.de
parent afac9e89

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

+0 −1
Original line number Diff line number Diff line
@@ -26,7 +26,6 @@ 
/*

 * High level FPU state handling functions:

 */

extern void fpu__prepare_read(struct fpu *fpu);

extern void fpu__prepare_write(struct fpu *fpu);

extern void fpu__save(struct fpu *fpu);

extern int  fpu__restore_sig(void __user *buf, int ia32_frame);

arch/x86/kernel/fpu/core.c

+0 −20
Original line number Diff line number Diff line
@@ -281,26 +281,6 @@ static void fpu__initialize(struct fpu *fpu) 
	trace_x86_fpu_init_state(fpu);

}



/*

 * This function must be called before we read a task's fpstate.

 *

 * There's two cases where this gets called:

 *

 * - for the current task (when coredumping), in which case we have

 *   to save the latest FPU registers into the fpstate,

 *

 * - or it's called for stopped tasks (ptrace), in which case the

 *   registers were already saved by the context-switch code when

 *   the task scheduled out.

 *

 * If the task has used the FPU before then save it.

 */

void fpu__prepare_read(struct fpu *fpu)

{

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

		fpu__save(fpu);

}



/*

 * This function must be called before we write a task's fpstate.

 *

arch/x86/kernel/fpu/regset.c

+19 −3
Original line number Diff line number Diff line
@@ -28,6 +28,22 @@ int regset_xregset_fpregs_active(struct task_struct *target, const struct user_r 
		return 0;

}



/*

 * The regset get() functions are invoked from:

 *

 *   - coredump to dump the current task's fpstate. If the current task

 *     owns the FPU then the memory state has to be synchronized and the

 *     FPU register state preserved. Otherwise fpstate is already in sync.

 *

 *   - ptrace to dump fpstate of a stopped task, in which case the registers

 *     have already been saved to fpstate on context switch.

 */

static void sync_fpstate(struct fpu *fpu)

{

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

		fpu__save(fpu);

}



int xfpregs_get(struct task_struct *target, const struct user_regset *regset,

		struct membuf to)

{
@@ -36,7 +52,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset, 
	if (!cpu_feature_enabled(X86_FEATURE_FXSR))

		return -ENODEV;



	fpu__prepare_read(fpu);

	sync_fpstate(fpu);



	if (!use_xsave()) {

		return membuf_write(&to, &fpu->state.fxsave,
@@ -96,7 +112,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset, 
	if (!cpu_feature_enabled(X86_FEATURE_XSAVE))

		return -ENODEV;



	fpu__prepare_read(fpu);

	sync_fpstate(fpu);



	copy_xstate_to_uabi_buf(to, &fpu->state.xsave, XSTATE_COPY_XSAVE);

	return 0;
@@ -287,7 +303,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, 
	struct user_i387_ia32_struct env;

	struct fxregs_state fxsave, *fx;



	fpu__prepare_read(fpu);

	sync_fpstate(fpu);



	if (!cpu_feature_enabled(X86_FEATURE_FPU))

		return fpregs_soft_get(target, regset, to);