[tip:x86/bsp-hotplug] x86/i387.c: Initialize thread xstate only on CPU0 only once

[tip-bot for Fenghua Yu <fenghua.yu@intel.com>]

Commit-ID:  cc5d167b58af1d858aa5a2ade158acb94af4df70
Gitweb:     http://git.kernel.org/tip/cc5d167b58af1d858aa5a2ade158acb94af4df70
Author:     Fenghua Yu <fenghua.yu@intel.com>
AuthorDate: Tue, 13 Nov 2012 11:32:50 -0800
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Wed, 14 Nov 2012 09:39:56 -0800

x86/i387.c: Initialize thread xstate only on CPU0 only once

init_thread_xstate() is only called once to avoid overriding xstate_size during
boot time or during CPU hotplug.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1352835171-3958-14-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/kernel/i387.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 675a050..245a71d 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -175,7 +175,11 @@ void __cpuinit fpu_init(void)
 		cr0 |= X86_CR0_EM;
 	write_cr0(cr0);
 
-	if (!smp_processor_id())
+	/*
+	 * init_thread_xstate is only called once to avoid overriding
+	 * xstate_size during boot time or during CPU hotplug.
+	 */
+	if (xstate_size == 0)
 		init_thread_xstate();
 
 	mxcsr_feature_mask_init();