x86/fpu: Move the signal frame handling code closer to each other

Consolidate more signal frame related functions:

   text      data    bss     dec       filename
   14108070  2575280 1634304 18317654  vmlinux.before
   14107944  2575344 1634304 18317592  vmlinux.after

Also, while moving it, rename alloc_mathframe() to fpu__alloc_mathframe().

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

@@ -325,7 +325,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
 	if (fpu->fpstate_active) {
 		unsigned long fx_aligned, math_size;
 
-		sp = alloc_mathframe(sp, 1, &fx_aligned, &math_size);
+		sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);
 		*fpstate = (struct _fpstate_ia32 __user *) sp;
 		if (copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned,
 				    math_size) < 0)

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

@@ -53,6 +53,7 @@ extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
  */
 extern void fpu__save(struct fpu *fpu);
 extern void fpu__restore(void);
+extern int  fpu__restore_sig(void __user *buf, int ia32_frame);
 extern void fpu__drop(struct fpu *fpu);
 extern int  fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu);
 extern void fpu__reset(struct fpu *fpu);
@@ -497,25 +498,6 @@ static inline void switch_fpu_finish(struct fpu *new_fpu, fpu_switch_t fpu_switc
  * Signal frame handlers...
  */
 extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fx, int size);
-extern int __fpu__restore_sig(void __user *buf, void __user *fx, int size);
-
-static inline int xstate_sigframe_size(void)
-{
-	return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size;
-}
-
-static inline int fpu__restore_sig(void __user *buf, int ia32_frame)
-{
-	void __user *buf_fx = buf;
-	int size = xstate_sigframe_size();
-
-	if (ia32_frame && use_fxsr()) {
-		buf_fx = buf + sizeof(struct i387_fsave_struct);
-		size += sizeof(struct i387_fsave_struct);
-	}
-
-	return __fpu__restore_sig(buf, buf_fx, size);
-}
 
 /*
  * Needs to be preemption-safe.
@@ -565,20 +547,8 @@ static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk)
 	}
 }
 
-static inline unsigned long
-alloc_mathframe(unsigned long sp, int ia32_frame, unsigned long *buf_fx,
-		unsigned long *size)
-{
-	unsigned long frame_size = xstate_sigframe_size();
-
-	*buf_fx = sp = round_down(sp - frame_size, 64);
-	if (ia32_frame && use_fxsr()) {
-		frame_size += sizeof(struct i387_fsave_struct);
-		sp -= sizeof(struct i387_fsave_struct);
-	}
-
-	*size = frame_size;
-	return sp;
-}
+unsigned long
+fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
+		     unsigned long *buf_fx, unsigned long *size);
 
 #endif /* _ASM_X86_FPU_INTERNAL_H */

arch/x86/kernel/fpu/xstate.c

@@ -388,7 +388,7 @@ static inline int restore_user_xstate(void __user *buf, u64 xbv, int fx_only)
 		return frstor_user(buf);
 }
 
-int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
+static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 {
 	int ia32_fxstate = (buf != buf_fx);
 	struct task_struct *tsk = current;
@@ -482,6 +482,43 @@ int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 	return 0;
 }
 
+static inline int xstate_sigframe_size(void)
+{
+	return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size;
+}
+
+/*
+ * Restore FPU state from a sigframe:
+ */
+int fpu__restore_sig(void __user *buf, int ia32_frame)
+{
+	void __user *buf_fx = buf;
+	int size = xstate_sigframe_size();
+
+	if (ia32_frame && use_fxsr()) {
+		buf_fx = buf + sizeof(struct i387_fsave_struct);
+		size += sizeof(struct i387_fsave_struct);
+	}
+
+	return __fpu__restore_sig(buf, buf_fx, size);
+}
+
+unsigned long
+fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
+		     unsigned long *buf_fx, unsigned long *size)
+{
+	unsigned long frame_size = xstate_sigframe_size();
+
+	*buf_fx = sp = round_down(sp - frame_size, 64);
+	if (ia32_frame && use_fxsr()) {
+		frame_size += sizeof(struct i387_fsave_struct);
+		sp -= sizeof(struct i387_fsave_struct);
+	}
+
+	*size = frame_size;
+
+	return sp;
+}
 /*
  * Prepare the SW reserved portion of the fxsave memory layout, indicating
  * the presence of the extended state information in the memory layout

arch/x86/kernel/signal.c

@@ -219,8 +219,8 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
 	}
 
 	if (fpu->fpstate_active) {
-		sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
-				     &buf_fx, &math_size);
+		sp = fpu__alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
+					  &buf_fx, &math_size);
 		*fpstate = (void __user *)sp;
 	}