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authorIngo Molnar <mingo@kernel.org>2015-04-30 10:09:26 +0300
committerIngo Molnar <mingo@kernel.org>2015-05-19 16:48:03 +0300
commit5e907bb0459399b0d1cc8d4c7e9f363a995b748a (patch)
tree7a0ba64607b1e538740ef6f5d6b95a91c80418fc /arch/x86/include/asm/alternative.h
parent2e85591a6ca2ad84741d2859753be5497d74bd42 (diff)
downloadlinux-5e907bb0459399b0d1cc8d4c7e9f363a995b748a.tar.xz
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>
Diffstat (limited to 'arch/x86/include/asm/alternative.h')
-rw-r--r--arch/x86/include/asm/alternative.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index ba32af062f61..7bfc85bbb8ff 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -52,6 +52,12 @@ struct alt_instr {
u8 padlen; /* length of build-time padding */
} __packed;
+/*
+ * Debug flag that can be tested to see whether alternative
+ * instructions were patched in already:
+ */
+extern int alternatives_patched;
+
extern void alternative_instructions(void);
extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);