x86/fpu: Rename fpu_init() to fpu__cpu_init()

fpu_init() is a bit of a misnomer in that it (falsely) creates the
impression that it's related to the (old) fpu_finit() function,
which initializes FPU ctx state.

Rename it to fpu__cpu_init() to make its boot time initialization
clear, and to move it to the fpu__*() namespace.

Also fix and extend its comment block to point out that it's
called not only on the boot CPU, but on secondary CPUs as well.
Reviewed-by: NBorislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
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: NIngo Molnar <mingo@kernel.org>

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

@@ -39,7 +39,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
 #endif
 
 extern unsigned int mxcsr_feature_mask;
-extern void fpu_init(void);
+extern void fpu__cpu_init(void);
 extern void eager_fpu_init(void);
 
 DECLARE_PER_CPU(struct task_struct *, fpu_owner_task);

arch/x86/kernel/cpu/common.c

@@ -1439,7 +1439,7 @@ void cpu_init(void)
 	clear_all_debug_regs();
 	dbg_restore_debug_regs();
 
-	fpu_init();
+	fpu__cpu_init();
 
 	if (is_uv_system())
 		uv_cpu_init();
@@ -1495,7 +1495,7 @@ void cpu_init(void)
 	clear_all_debug_regs();
 	dbg_restore_debug_regs();
 
-	fpu_init();
+	fpu__cpu_init();
 }
 #endif
 

arch/x86/kernel/i387.c

@@ -183,11 +183,13 @@ static void init_thread_xstate(void)
 }
 
 /*
- * Called at bootup to set up the initial FPU state that is later cloned
- * into all processes.
+ * Called on the boot CPU at bootup to set up the initial FPU state that
+ * is later cloned into all processes.
+ *
+ * Also called on secondary CPUs to set up the FPU state of their
+ * idle threads.
  */
-
-void fpu_init(void)
+void fpu__cpu_init(void)
 {
 	unsigned long cr0;
 	unsigned long cr4_mask = 0;

arch/x86/xen/enlighten.c

@@ -1423,7 +1423,7 @@ static void xen_pvh_set_cr_flags(int cpu)
 		return;
 	/*
 	 * For BSP, PSE PGE are set in probe_page_size_mask(), for APs
-	 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu_init.
+	 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu__cpu_init().
 	*/
 	if (cpu_has_pse)
 		cr4_set_bits_and_update_boot(X86_CR4_PSE);