diff options
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 29 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/regset.c | 6 |
3 files changed, 33 insertions, 3 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 62d13d515f95..3cc2086b97f8 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -22,6 +22,7 @@ * High level FPU state handling functions: */ extern void fpu__activate_curr(struct fpu *fpu); +extern void fpu__activate_fpstate_read(struct fpu *fpu); extern void fpu__activate_fpstate(struct fpu *fpu); extern void fpu__save(struct fpu *fpu); extern void fpu__restore(struct fpu *fpu); diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index b41049247cfa..174add372bb8 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -296,6 +296,35 @@ void fpu__activate_curr(struct fpu *fpu) EXPORT_SYMBOL_GPL(fpu__activate_curr); /* + * This function must be called before we read a task's fpstate. + * + * If the task has not used the FPU before then initialize its + * fpstate. + * + * If the task has used the FPU before then save it. + */ +void fpu__activate_fpstate_read(struct fpu *fpu) +{ + /* + * If fpregs are active (in the current CPU), then + * copy them to the fpstate: + */ + if (fpu->fpregs_active) { + fpu__save(fpu); + } else { + if (fpu->fpstate_active) { + /* Invalidate any lazy state: */ + fpu->last_cpu = -1; + } else { + fpstate_init(&fpu->state); + + /* Safe to do for current and for stopped child tasks: */ + fpu->fpstate_active = 1; + } + } +} + +/* * This function must be called before we read or write a task's fpstate. * * If the task has not used the FPU before then initialize its diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c index a1f97d9d6a45..4e40585a9c8f 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -33,7 +33,7 @@ int xfpregs_get(struct task_struct *target, const struct user_regset *regset, if (!cpu_has_fxsr) return -ENODEV; - fpu__activate_fpstate(fpu); + fpu__activate_fpstate_read(fpu); fpstate_sanitize_xstate(fpu); return user_regset_copyout(&pos, &count, &kbuf, &ubuf, @@ -82,7 +82,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset, if (!cpu_has_xsave) return -ENODEV; - fpu__activate_fpstate(fpu); + fpu__activate_fpstate_read(fpu); xsave = &fpu->state.xsave; @@ -273,7 +273,7 @@ int fpregs_get(struct task_struct *target, const struct user_regset *regset, struct fpu *fpu = &target->thread.fpu; struct user_i387_ia32_struct env; - fpu__activate_fpstate(fpu); + fpu__activate_fpstate_read(fpu); if (!static_cpu_has(X86_FEATURE_FPU)) return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf); |