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Message-ID: <tip-pzrydfee75mhq64kazxmf9it@git.kernel.org>
Date: Mon, 6 Mar 2017 23:25:31 -0800
From: tip-bot for Arnaldo Carvalho de Melo <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: tglx@...utronix.de, dsahern@...il.com, hpa@...or.com,
mingo@...nel.org, adrian.hunter@...el.com, namhyung@...nel.org,
acme@...hat.com, linux-kernel@...r.kernel.org,
elena.reshetova@...el.com, wangnan0@...wei.com, jolsa@...nel.org
Subject: [tip:perf/core] tools arch x86: Include asm/cmpxchg.h
Commit-ID: 3337e682d9f3043bb0b925d976558ed5c41b0a09
Gitweb: http://git.kernel.org/tip/3337e682d9f3043bb0b925d976558ed5c41b0a09
Author: Arnaldo Carvalho de Melo <acme@...hat.com>
AuthorDate: Wed, 22 Feb 2017 16:54:53 -0300
Committer: Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Fri, 3 Mar 2017 19:07:13 -0300
tools arch x86: Include asm/cmpxchg.h
Will be included from atomic.h and used in refcount.h
Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: David Ahern <dsahern@...il.com>
Cc: Elena Reshetova <elena.reshetova@...el.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Wang Nan <wangnan0@...wei.com>
Link: http://lkml.kernel.org/n/tip-pzrydfee75mhq64kazxmf9it@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
tools/arch/x86/include/asm/cmpxchg.h | 89 ++++++++++++++++++++++++++++++++++++
tools/perf/MANIFEST | 1 +
tools/scripts/Makefile.include | 9 ++++
3 files changed, 99 insertions(+)
diff --git a/tools/arch/x86/include/asm/cmpxchg.h b/tools/arch/x86/include/asm/cmpxchg.h
new file mode 100644
index 0000000..f525326
--- /dev/null
+++ b/tools/arch/x86/include/asm/cmpxchg.h
@@ -0,0 +1,89 @@
+#ifndef TOOLS_ASM_X86_CMPXCHG_H
+#define TOOLS_ASM_X86_CMPXCHG_H
+
+#include <linux/compiler.h>
+
+/*
+ * Non-existant functions to indicate usage errors at link time
+ * (or compile-time if the compiler implements __compiletime_error().
+ */
+extern void __cmpxchg_wrong_size(void)
+ __compiletime_error("Bad argument size for cmpxchg");
+
+/*
+ * Constants for operation sizes. On 32-bit, the 64-bit size it set to
+ * -1 because sizeof will never return -1, thereby making those switch
+ * case statements guaranteeed dead code which the compiler will
+ * eliminate, and allowing the "missing symbol in the default case" to
+ * indicate a usage error.
+ */
+#define __X86_CASE_B 1
+#define __X86_CASE_W 2
+#define __X86_CASE_L 4
+#ifdef __x86_64__
+#define __X86_CASE_Q 8
+#else
+#define __X86_CASE_Q -1 /* sizeof will never return -1 */
+#endif
+
+/*
+ * Atomic compare and exchange. Compare OLD with MEM, if identical,
+ * store NEW in MEM. Return the initial value in MEM. Success is
+ * indicated by comparing RETURN with OLD.
+ */
+#define __raw_cmpxchg(ptr, old, new, size, lock) \
+({ \
+ __typeof__(*(ptr)) __ret; \
+ __typeof__(*(ptr)) __old = (old); \
+ __typeof__(*(ptr)) __new = (new); \
+ switch (size) { \
+ case __X86_CASE_B: \
+ { \
+ volatile u8 *__ptr = (volatile u8 *)(ptr); \
+ asm volatile(lock "cmpxchgb %2,%1" \
+ : "=a" (__ret), "+m" (*__ptr) \
+ : "q" (__new), "0" (__old) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_W: \
+ { \
+ volatile u16 *__ptr = (volatile u16 *)(ptr); \
+ asm volatile(lock "cmpxchgw %2,%1" \
+ : "=a" (__ret), "+m" (*__ptr) \
+ : "r" (__new), "0" (__old) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_L: \
+ { \
+ volatile u32 *__ptr = (volatile u32 *)(ptr); \
+ asm volatile(lock "cmpxchgl %2,%1" \
+ : "=a" (__ret), "+m" (*__ptr) \
+ : "r" (__new), "0" (__old) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_Q: \
+ { \
+ volatile u64 *__ptr = (volatile u64 *)(ptr); \
+ asm volatile(lock "cmpxchgq %2,%1" \
+ : "=a" (__ret), "+m" (*__ptr) \
+ : "r" (__new), "0" (__old) \
+ : "memory"); \
+ break; \
+ } \
+ default: \
+ __cmpxchg_wrong_size(); \
+ } \
+ __ret; \
+})
+
+#define __cmpxchg(ptr, old, new, size) \
+ __raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)
+
+#define cmpxchg(ptr, old, new) \
+ __cmpxchg(ptr, old, new, sizeof(*(ptr)))
+
+
+#endif /* TOOLS_ASM_X86_CMPXCHG_H */
diff --git a/tools/perf/MANIFEST b/tools/perf/MANIFEST
index 8672f83..e2c5219 100644
--- a/tools/perf/MANIFEST
+++ b/tools/perf/MANIFEST
@@ -12,6 +12,7 @@ tools/arch/sparc/include/asm/barrier_32.h
tools/arch/sparc/include/asm/barrier_64.h
tools/arch/tile/include/asm/barrier.h
tools/arch/x86/include/asm/barrier.h
+tools/arch/x86/include/asm/cmpxchg.h
tools/arch/x86/include/asm/cpufeatures.h
tools/arch/x86/include/asm/disabled-features.h
tools/arch/x86/include/asm/required-features.h
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index 621578a..fc74db6 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -43,6 +43,15 @@ ifneq ($(CC), clang)
EXTRA_WARNINGS += -Wstrict-aliasing=3
endif
+# Hack to avoid type-punned warnings on old systems such as RHEL5:
+# We should be changing CFLAGS and checking gcc version, but this
+# will do for now and keep the above -Wstrict-aliasing=3 in place
+# in newer systems.
+# Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h
+ifneq ($(filter 3.%,$(MAKE_VERSION)),) # make-3
+EXTRA_WARNINGS += -fno-strict-aliasing
+endif
+
ifneq ($(findstring $(MAKEFLAGS), w),w)
PRINT_DIR = --no-print-directory
else
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