From 5e907bb0459399b0d1cc8d4c7e9f363a995b748a Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@kernel.org>
Date: Thu, 30 Apr 2015 09:09:26 +0200
Subject: x86/alternatives, x86/fpu: Add 'alternatives_patched' debug flag and
 use it in xsave_state()

We'd like to use xsave_state() earlier, but its SYSTEM_BOOTING check
is too imprecise.

The real condition that xsave_state() would like to check is whether
alternative XSAVE instructions were patched into the kernel image
already.

Add such a (read-mostly) debug flag and use it in xsave_state().

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/kernel/alternative.c | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'arch/x86/kernel/alternative.c')

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index aef653193160..7fe097235376 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -21,6 +21,10 @@
 #include <asm/io.h>
 #include <asm/fixmap.h>
 
+int __read_mostly alternatives_patched;
+
+EXPORT_SYMBOL_GPL(alternatives_patched);
+
 #define MAX_PATCH_LEN (255-1)
 
 static int __initdata_or_module debug_alternative;
@@ -627,6 +631,7 @@ void __init alternative_instructions(void)
 	apply_paravirt(__parainstructions, __parainstructions_end);
 
 	restart_nmi();
+	alternatives_patched = 1;
 }
 
 /**
-- 
cgit