diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 0148791acc49..4c669f3b54b4 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -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); diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 9ff467bb4894..d390644e5fa1 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -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 == ¤t->thread.fpu) - fpu__save(fpu); -} - /* * This function must be called before we write a task's fpstate. * diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c index 4b799e42ebc7..937adf702b37 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -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 == ¤t->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);