From 1b1d9258181bae199dc940f4bd0298126b9a73d9 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 18 Dec 2009 16:12:56 +0000 Subject: 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 Cc: Nick Piggin Cc: Linus Torvalds Cc: Andrew Morton LKML-Reference: <4B2BB8180200007800026AE7@vpn.id2.novell.com> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/alternative.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'arch/x86/include/asm/alternative.h') diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 69b74a7..3b5b828 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 -- cgit v1.1