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authorJan Beulich <JBeulich@novell.com>2009-12-18 16:12:56 +0000
committerIngo Molnar <mingo@elte.hu>2009-12-30 11:57:31 +0100
commit1b1d9258181bae199dc940f4bd0298126b9a73d9 (patch)
treeb17ca149d943051fc76e79b75fc4b89c61b524a2 /arch/x86/include/asm/alternative.h
parent499a5f1efa0b0ac56ec5d060412aed84ae68e63e (diff)
x86-64: Modify copy_user_generic() alternatives mechanism
In order to avoid unnecessary chains of branches, rather than implementing copy_user_generic() as a function consisting of just a single (possibly patched) branch, instead properly deal with patching call instructions in the alternative instructions framework, and move the patching into the callers. As a follow-on, one could also introduce something like __EXPORT_SYMBOL_ALT() to avoid patching call sites in modules. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <4B2BB8180200007800026AE7@vpn.id2.novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/include/asm/alternative.h')
-rw-r--r--arch/x86/include/asm/alternative.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 69b74a7b877..3b5b828767b 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -125,11 +125,16 @@ static inline void alternatives_smp_switch(int smp) {}
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
: output : "i" (0), ## input)
+/* Like alternative_io, but for replacing a direct call with another one. */
+#define alternative_call(oldfunc, newfunc, feature, output, input...) \
+ asm volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \
+ : output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
+
/*
* use this macro(s) if you need more than one output parameter
* in alternative_io
*/
-#define ASM_OUTPUT2(a, b) a, b
+#define ASM_OUTPUT2(a...) a
struct paravirt_patch_site;
#ifdef CONFIG_PARAVIRT