The LOCK_PREFIX is mostly used in inline asm, but also used by
atomic64_cx8_32.S
Let's unify the definition by using ASM() macro.
This was previously cleaned up by 77f48ec28e4c ("x86/alternatives:
Macrofy lock prefixes to work around GCC inlining bugs").
Now, I am refactoring the code without using the macros approach.
The new header <asm/alternative-common.h> contains macros that
can be used by C and assembly.
Signed-off-by: Masahiro Yamada <[email protected]>
---
arch/x86/include/asm/alternative-asm.h | 14 +--------
arch/x86/include/asm/alternative-common.h | 47 +++++++++++++++++++++++++++++++
arch/x86/include/asm/alternative.h | 37 +-----------------------
3 files changed, 49 insertions(+), 49 deletions(-)
create mode 100644 arch/x86/include/asm/alternative-common.h
diff --git a/arch/x86/include/asm/alternative-asm.h
b/arch/x86/include/asm/alternative-asm.h
index 31b627b..7425514 100644
--- a/arch/x86/include/asm/alternative-asm.h
+++ b/arch/x86/include/asm/alternative-asm.h
@@ -4,21 +4,9 @@
#ifdef __ASSEMBLY__
+#include <asm/alternative-common.h>
#include <asm/asm.h>
-#ifdef CONFIG_SMP
- .macro LOCK_PREFIX
-672: lock
- .pushsection .smp_locks,"a"
- .balign 4
- .long 672b - .
- .popsection
- .endm
-#else
- .macro LOCK_PREFIX
- .endm
-#endif
-
/*
* Issue one struct alt_instr descriptor entry (need to put it into
* the section .altinstructions, see below). This entry contains
diff --git a/arch/x86/include/asm/alternative-common.h
b/arch/x86/include/asm/alternative-common.h
new file mode 100644
index 0000000..ae0b58f
--- /dev/null
+++ b/arch/x86/include/asm/alternative-common.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_ALTERNATIVE_COMMON_H
+#define _ASM_X86_ALTERNATIVE_COMMON_H
+
+#include <linux/linkage.h>
+
+/*
+ * Alternative inline assembly for SMP.
+ *
+ * The LOCK_PREFIX macro defined here replaces the LOCK and
+ * LOCK_PREFIX macros used everywhere in the source tree.
+ *
+ * SMP alternatives use the same data structures as the other
+ * alternatives and the X86_FEATURE_UP flag to indicate the case of a
+ * UP system running a SMP kernel. The existing apply_alternatives()
+ * works fine for patching a SMP kernel for UP.
+ *
+ * The SMP alternative tables can be kept after boot and contain both
+ * UP and SMP versions of the instructions to allow switching back to
+ * SMP at runtime, when hotplugging in a new CPU, which is especially
+ * useful in virtualized environments.
+ *
+ * The very common lock prefix is handled as special case in a
+ * separate table which is a pure address list without replacement ptr
+ * and size information. That keeps the table sizes small.
+ */
+
+#include <linux/linkage.h>
+#include <linux/stringify.h>
+
+#ifdef CONFIG_SMP
+
+#define LOCK_PREFIX_HERE \
+ASM( .pushsection .smp_locks,"a" )\
+ASM( .balign 4 )\
+ASM( .long 671f - . )\
+ASM( .popsection )\
+ASM( 671: )
+
+#define LOCK_PREFIX LOCK_PREFIX_HERE ASM(lock)
+
+#else /* ! CONFIG_SMP */
+#define LOCK_PREFIX_HERE ASM()
+#define LOCK_PREFIX ASM()
+#endif
+
+#endif /* _ASM_X86_ALTERNATIVE_COMMON_H */
diff --git a/arch/x86/include/asm/alternative.h
b/arch/x86/include/asm/alternative.h
index 4cd6a3b..157967c 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -7,44 +7,9 @@
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/stringify.h>
+#include <asm/alternative-common.h>
#include <asm/asm.h>
-/*
- * Alternative inline assembly for SMP.
- *
- * The LOCK_PREFIX macro defined here replaces the LOCK and
- * LOCK_PREFIX macros used everywhere in the source tree.
- *
- * SMP alternatives use the same data structures as the other
- * alternatives and the X86_FEATURE_UP flag to indicate the case of a
- * UP system running a SMP kernel. The existing apply_alternatives()
- * works fine for patching a SMP kernel for UP.
- *
- * The SMP alternative tables can be kept after boot and contain both
- * UP and SMP versions of the instructions to allow switching back to
- * SMP at runtime, when hotplugging in a new CPU, which is especially
- * useful in virtualized environments.
- *
- * The very common lock prefix is handled as special case in a
- * separate table which is a pure address list without replacement ptr
- * and size information. That keeps the table sizes small.
- */
-
-#ifdef CONFIG_SMP
-#define LOCK_PREFIX_HERE \
- ".pushsection .smp_locks,\"a\"\n" \
- ".balign 4\n" \
- ".long 671f - .\n" /* offset */ \
- ".popsection\n" \
- "671:"
-
-#define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; "
-
-#else /* ! CONFIG_SMP */
-#define LOCK_PREFIX_HERE ""
-#define LOCK_PREFIX ""
-#endif
-
struct alt_instr {
s32 instr_offset; /* original instruction */
s32 repl_offset; /* offset to replacement instruction */
--
2.7.4
