x86/fpu: Move all the fpu__*() high level methods closer to each other

The fpu__*() methods are closely related, but they are defined
in scattered places within the FPU code.

Concentrate them, and also uninline fpu__save(), fpu__drop()
and fpu__reset() to save about 5K of kernel text on 64-bit kernels:

   text            data    bss     dec        filename
   14113063        2575280 1634304 18322647   vmlinux.before
   14108070        2575280 1634304 18317654   vmlinux.after

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/include/asm/fpu/internal.h

@@ -46,10 +46,19 @@ extern void fpu__init_system(struct cpuinfo_x86 *c);
 
 extern void fpu__activate_curr(struct fpu *fpu);
 extern void fpstate_init(struct fpu *fpu);
-extern void fpu__clear(struct task_struct *tsk);
 
 extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
+
+/*
+ * High level FPU state handling functions:
+ */
+extern void fpu__save(struct fpu *fpu);
 extern void fpu__restore(void);
+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);
+extern void fpu__clear(struct task_struct *tsk);
+
 extern void fpu__init_check_bugs(void);
 extern void fpu__resume_cpu(void);
 
@@ -287,8 +296,6 @@ static inline int copy_fpregs_to_fpstate(struct fpu *fpu)
 	return 0;
 }
 
-extern void fpu__save(struct fpu *fpu);
-
 static inline int __copy_fpstate_to_fpregs(struct fpu *fpu)
 {
 	if (use_xsave())
@@ -382,33 +389,6 @@ static inline void fpregs_deactivate(struct fpu *fpu)
 	__fpregs_deactivate_hw();
 }
 
-/*
- * Drops current FPU state: deactivates the fpregs and
- * the fpstate. NOTE: it still leaves previous contents
- * in the fpregs in the eager-FPU case.
- *
- * This function can be used in cases where we know that
- * a state-restore is coming: either an explicit one,
- * or a reschedule.
- */
-static inline void fpu__drop(struct fpu *fpu)
-{
-	preempt_disable();
-	fpu->counter = 0;
-
-	if (fpu->fpregs_active) {
-		/* Ignore delayed exceptions from user space */
-		asm volatile("1: fwait\n"
-			     "2:\n"
-			     _ASM_EXTABLE(1b, 2b));
-		fpregs_deactivate(fpu);
-	}
-
-	fpu->fpstate_active = 0;
-
-	preempt_enable();
-}
-
 static inline void restore_init_xstate(void)
 {
 	if (use_xsave())
@@ -417,17 +397,6 @@ static inline void restore_init_xstate(void)
 		fxrstor_checking(&init_xstate_ctx.i387);
 }
 
-/*
- * Reset the FPU state back to init state.
- */
-static inline void fpu__reset(struct fpu *fpu)
-{
-	if (!use_eager_fpu())
-		fpu__drop(fpu);
-	else
-		restore_init_xstate();
-}
-
 /*
  * Definitions for the eXtended Control Register instructions
  */
@@ -597,8 +566,6 @@ static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk)
 	}
 }
 
-extern int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu);
-
 static inline unsigned long
 alloc_mathframe(unsigned long sp, int ia32_frame, unsigned long *buf_fx,
 		unsigned long *size)

arch/x86/kernel/fpu/core.c

@@ -348,6 +348,44 @@ void fpu__restore(void)
 }
 EXPORT_SYMBOL_GPL(fpu__restore);
 
+/*
+ * Drops current FPU state: deactivates the fpregs and
+ * the fpstate. NOTE: it still leaves previous contents
+ * in the fpregs in the eager-FPU case.
+ *
+ * This function can be used in cases where we know that
+ * a state-restore is coming: either an explicit one,
+ * or a reschedule.
+ */
+void fpu__drop(struct fpu *fpu)
+{
+	preempt_disable();
+	fpu->counter = 0;
+
+	if (fpu->fpregs_active) {
+		/* Ignore delayed exceptions from user space */
+		asm volatile("1: fwait\n"
+			     "2:\n"
+			     _ASM_EXTABLE(1b, 2b));
+		fpregs_deactivate(fpu);
+	}
+
+	fpu->fpstate_active = 0;
+
+	preempt_enable();
+}
+
+/*
+ * Reset the FPU state back to init state:
+ */
+void fpu__reset(struct fpu *fpu)
+{
+	if (!use_eager_fpu())
+		fpu__drop(fpu);
+	else
+		restore_init_xstate();
+}
+
 /*
  * Called by sys_execve() to clear the FPU fpregs, so that FPU state
  * of the previous binary does not leak over into the exec()ed binary: