Commit 5a32fac8 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
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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
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+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);
+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.
 *
+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);