From 62db6871ae862fbd7f7abfebffe501b170698a8b Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@kernel.org>
Date: Sat, 25 Apr 2015 06:50:09 +0200
Subject: [PATCH] x86/fpu: Propagate once per boot quirk into
 fpu__init_system_xstate()

Linearize the call sequence in xsave_init():

	fpu__init_system_xstate();
	fpu__init_cpu_xstate();

We do this by propagating the boot-once quirk into
fpu__init_system_xstate(). fpu__init_cpu_xstate() is
safe to be called multiple time.

Reviewed-by: Borislav 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: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/fpu/xsave.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/fpu/xsave.c b/arch/x86/kernel/fpu/xsave.c
index fd656cbdd315..9d5ff90916b1 100644
--- a/arch/x86/kernel/fpu/xsave.c
+++ b/arch/x86/kernel/fpu/xsave.c
@@ -652,6 +652,11 @@ static void __init init_xstate_size(void)
 void fpu__init_system_xstate(void)
 {
 	unsigned int eax, ebx, ecx, edx;
+	static bool on_boot_cpu = 1;
+
+	if (!on_boot_cpu)
+		return;
+	on_boot_cpu = 0;
 
 	if (!cpu_has_xsave) {
 		pr_info("x86/fpu: Legacy x87 FPU detected.\n");
@@ -714,14 +719,8 @@ void fpu__init_system_xstate(void)
  */
 void xsave_init(void)
 {
-	static char on_boot_cpu = 1;
-
-	if (on_boot_cpu) {
-		on_boot_cpu = 0;
-		fpu__init_system_xstate();
-	} else {
-		fpu__init_cpu_xstate();
-	}
+	fpu__init_system_xstate();
+	fpu__init_cpu_xstate();
 }
 
 /*
-- 
2.20.1