diff options
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 40 |
1 files changed, 10 insertions, 30 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 11055f51e67a..10663b02ee22 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -271,46 +271,26 @@ static inline void fpu_fxsave(struct fpu *fpu) * The legacy FNSAVE instruction cleared all FPU state * unconditionally, so registers are essentially destroyed. * Modern FPU state can be kept in registers, if there are - * no pending FP exceptions. (Note the FIXME below.) + * no pending FP exceptions. */ static inline int copy_fpregs_to_fpstate(struct fpu *fpu) { - if (use_xsave()) { + if (likely(use_xsave())) { xsave_state(&fpu->state->xsave); + return 1; + } - /* - * xsave header may indicate the init state of the FP. - */ - if (!(fpu->state->xsave.header.xfeatures & XSTATE_FP)) - goto keep_fpregs; - } else { - if (use_fxsr()) { - fpu_fxsave(fpu); - } else { - /* FNSAVE always clears FPU registers: */ - asm volatile("fnsave %[fx]; fwait" - : [fx] "=m" (fpu->state->fsave)); - goto drop_fpregs; - } + if (likely(use_fxsr())) { + fpu_fxsave(fpu); + return 1; } /* - * If exceptions are pending, we need to clear them so - * that we don't randomly get exceptions later. - * - * FIXME! Is this perhaps only true for the old-style - * irq13 case? Maybe we could leave the x87 state - * intact otherwise? + * Legacy FPU register saving, FNSAVE always clears FPU registers, + * so we have to mark them inactive: */ - if (unlikely(fpu->state->fxsave.swd & X87_FSW_ES)) { - asm volatile("fnclex"); - goto drop_fpregs; - } - -keep_fpregs: - return 1; + asm volatile("fnsave %[fx]; fwait" : [fx] "=m" (fpu->state->fsave)); -drop_fpregs: return 0; } |