Why does copy_fpstate_to_sigframe() do copy_fxregs_to_kernel() in the ia32_fxstate case? I don't know. It just does. Maybe it was required at some point, maybe it was added by accident and nobody noticed it because it makes no difference. In copy_fpstate_to_sigframe() we stash the FPU state into the task's stackframe. Then the CPU's FPU registers (and its fpu->state) are cleared (handle_signal() does fpu__clear()). So it makes *no* difference what happens to fpu->state after copy_fpregs_to_sigframe(). Remove copy_fxregs_to_kernel() since it does not matter what it does and save a few cycles. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> --- arch/x86/kernel/fpu/signal.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 42e0f98f34f54..3a59c578440e2 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -174,9 +174,6 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) /* Save the live register state to the user directly. */ if (copy_fpregs_to_sigframe(buf_fx)) return -1; - /* Update the thread's fxstate to save the fsave header. */ - if (ia32_fxstate) - copy_fxregs_to_kernel(fpu); /* Save the fsave header for the 32-bit frames. */ if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf)) -- 2.20.0.rc1
