[PATCH 3/7] x86, asmlinkage, paravirt: Don't rely on local assembler labels

From: Andi Kleen
Date: Tue Oct 22 2013 - 12:08:14 EST


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

The paravirt patching code assumes that it can reference a
local assembler label between two different top level assembler
statements. This does not work with LTO
where the assembler code may end up in different assembler files.

Replace it with extern / global /asm linkage labels.

This also removes one redundant copy of the macro.

Cc: jeremy@xxxxxxxx
Cc: x86@xxxxxxxxxx
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/paravirt_types.h | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index aab8f67..7549b8b 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -388,10 +388,11 @@ extern struct pv_lock_ops pv_lock_ops;
_paravirt_alt(insn_string, "%c[paravirt_typenum]", "%c[paravirt_clobber]")

/* Simple instruction patching code. */
-#define DEF_NATIVE(ops, name, code) \
- extern const char start_##ops##_##name[] __visible, \
- end_##ops##_##name[] __visible; \
- asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":")
+#define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t"
+
+#define DEF_NATIVE(ops, name, code) \
+ __visible extern const char start_##ops##_##name[], end_##ops##_##name[]; \
+ asm(NATIVE_LABEL("start_", ops, name) code NATIVE_LABEL("end_", ops, name))

unsigned paravirt_patch_nop(void);
unsigned paravirt_patch_ident_32(void *insnbuf, unsigned len);
--
1.8.3.1

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