x86/fpu: Rename save_xstate_sig() to copy_fpstate_to_sigframe()

Standardize the naming of save_xstate_sig() by renaming it to
copy_fpstate_to_sigframe(): this tells us at a glance that
the function copies an FPU fpstate to a signal frame.

This naming also follows the naming of copy_fpregs_to_fpstate().

Don't put 'xstate' into the name: since this is a generic name,
it's expected that the function is able to handle xstate frames
as well, beyond legacy frames.

xstate used to be the odd case in the x86 FPU code - now it's the
common case.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/ia32/ia32_signal.c

@@ -327,7 +327,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
 
 		sp = alloc_mathframe(sp, 1, &fx_aligned, &math_size);
 		*fpstate = (struct _fpstate_ia32 __user *) sp;
-		if (save_xstate_sig(*fpstate, (void __user *)fx_aligned,
+		if (copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
 				    math_size) < 0)
 			return (void __user *) -1L;
 	}

arch/x86/include/asm/fpu/internal.h

@@ -523,7 +523,7 @@ static inline void switch_fpu_finish(struct fpu *new_fpu, fpu_switch_t fpu_switc
 /*
  * Signal frame handlers...
  */
-extern int save_xstate_sig(void __user *buf, void __user *fx, int size);
+extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fx, int size);
 extern int __restore_xstate_sig(void __user *buf, void __user *fx, int size);
 
 static inline int xstate_sigframe_size(void)

arch/x86/kernel/fpu/xstate.c

@@ -293,7 +293,7 @@ static inline int save_user_xstate(struct xsave_struct __user *buf)
  * For [f]xsave state, update the SW reserved fields in the [f]xsave frame
  * indicating the absence/presence of the extended state to the user.
  */
-int save_xstate_sig(void __user *buf, void __user *buf_fx, int size)
+int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
 {
 	struct xsave_struct *xsave = &current->thread.fpu.state.xsave;
 	struct task_struct *tsk = current;

arch/x86/kernel/signal.c

@@ -235,7 +235,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 
 	/* save i387 and extended state */
 	if (fpu->fpstate_active &&
-	    save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
+	    copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0)
 		return (void __user *)-1L;
 
 	return (void __user *)sp;