tools arch x86: Include asm/cmpxchg.h

Will be included from atomic.h and used in refcount.h

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-pzrydfee75mhq64kazxmf9it@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/arch/x86/include/asm/cmpxchg.h b/tools/arch/x86/include/asm/cmpxchg.h
new file mode 100644 (file)
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 8672f835ae4eff2659ff314c40bf77d3730b7986..e2c52190cf287d06e10f50575f2b43a267d1c216 100644 (file)
--- 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 621578aa12d6fe456134369b97968126c3a1981e..fc74db62fef4d11851422586a87eb5dee6b17176 100644 (file)
--- 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