diff options
Diffstat (limited to 'arch/x86/include/asm/fpu/internal.h')
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 559dd3018fd42..3e0eedaacdac8 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -83,6 +83,7 @@ extern void fpstate_init_soft(struct swregs_state *soft); #else static inline void fpstate_init_soft(struct swregs_state *soft) {} #endif +extern void save_fpregs_to_fpstate(struct fpu *fpu); #define user_insn(insn, output, input...) \ ({ \ @@ -375,8 +376,6 @@ static inline int os_xrstor_safe(struct xregs_state *xstate, u64 mask) return err; } -extern int save_fpregs_to_fpstate(struct fpu *fpu); - static inline void __copy_kernel_to_fpregs(union fpregs_state *fpstate, u64 mask) { if (use_xsave()) { @@ -507,12 +506,17 @@ static inline void __fpregs_load_activate(void) static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) { if (static_cpu_has(X86_FEATURE_FPU) && !(current->flags & PF_KTHREAD)) { - if (!save_fpregs_to_fpstate(old_fpu)) - old_fpu->last_cpu = -1; - else - old_fpu->last_cpu = cpu; + save_fpregs_to_fpstate(old_fpu); + /* + * The save operation preserved register state, so the + * fpu_fpregs_owner_ctx is still @old_fpu. Store the + * current CPU number in @old_fpu, so the next return + * to user space can avoid the FPU register restore + * when is returns on the same CPU and still owns the + * context. + */ + old_fpu->last_cpu = cpu; - /* But leave fpu_fpregs_owner_ctx! */ trace_x86_fpu_regs_deactivated(old_fpu); } } |