diff options
| author | Jan Beulich <JBeulich@novell.com> | 2009-12-18 16:12:56 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-12-30 11:57:31 +0100 |
| commit | 1b1d9258181bae199dc940f4bd0298126b9a73d9 (patch) | |
| tree | b17ca149d943051fc76e79b75fc4b89c61b524a2 /arch/x86/include/asm/alternative.h | |
| parent | 499a5f1efa0b0ac56ec5d060412aed84ae68e63e (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.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 69b74a7b877f..3b5b828767b6 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 |