[PATCH 09/11] import recent include/linux/compiler*.h
Marc Kleine-Budde
mkl at pengutronix.de
Tue Feb 16 09:46:24 EST 2010
Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
---
include/linux/compiler-gcc.h | 30 +++++++++-
include/linux/compiler-gcc3.h | 11 +++-
include/linux/compiler-gcc4.h | 32 ++++++++++-
include/linux/compiler.h | 124 ++++++++++++++++++++++++++++++++++++++---
4 files changed, 180 insertions(+), 17 deletions(-)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 5c8351b..73dcf80 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -11,9 +11,19 @@
/* The "volatile" is due to gcc bugs */
#define barrier() __asm__ __volatile__("": : :"memory")
-/* This macro obfuscates arithmetic on a variable address so that gcc
- shouldn't recognize the original var, and make assumptions about it */
/*
+ * This macro obfuscates arithmetic on a variable address so that gcc
+ * shouldn't recognize the original var, and make assumptions about it.
+ *
+ * This is needed because the C standard makes it undefined to do
+ * pointer arithmetic on "objects" outside their boundaries and the
+ * gcc optimizers assume this is the case. In particular they
+ * assume such arithmetic does not wrap.
+ *
+ * A miscompilation has been observed because of this on PPC.
+ * To work around it we hide the relationship of the pointer and the object
+ * using this macro.
+ *
* Versions of the ppc64 compiler before 4.1 had a bug where use of
* RELOC_HIDE could trash r30. The bug can be worked around by changing
* the inline assembly constraint from =g to =r, in this particular
@@ -42,7 +52,15 @@
#define __deprecated __attribute__((deprecated))
#define __packed __attribute__((packed))
#define __weak __attribute__((weak))
-#define __naked __attribute__((naked))
+
+/*
+ * it doesn't make sense on ARM (currently the only user of __naked) to trace
+ * naked functions because then mcount is called without stack and frame pointer
+ * being set up and there is no chance to restore the lr register to the value
+ * before mcount was called.
+ */
+#define __naked __attribute__((naked)) notrace
+
#define __noreturn __attribute__((noreturn))
/*
@@ -61,3 +79,9 @@
#define noinline __attribute__((noinline))
#define __attribute_const__ __attribute__((__const__))
#define __maybe_unused __attribute__((unused))
+#define __always_unused __attribute__((unused))
+
+#define __gcc_header(x) #x
+#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
+#define gcc_header(x) _gcc_header(x)
+#include gcc_header(__GNUC__)
diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
index e5eb795..b721129 100644
--- a/include/linux/compiler-gcc3.h
+++ b/include/linux/compiler-gcc3.h
@@ -2,8 +2,9 @@
#error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
#endif
-/* These definitions are for GCC v3.x. */
-#include <linux/compiler-gcc.h>
+#if __GNUC_MINOR__ < 2
+# error Sorry, your compiler is too old - please upgrade it.
+#endif
#if __GNUC_MINOR__ >= 3
# define __used __attribute__((__used__))
@@ -15,6 +16,12 @@
#define __must_check __attribute__((warn_unused_result))
#endif
+#ifdef CONFIG_GCOV_KERNEL
+# if __GNUC_MINOR__ < 4
+# error "GCOV profiling support for gcc versions below 3.4 not included"
+# endif /* __GNUC_MINOR__ */
+#endif /* CONFIG_GCOV_KERNEL */
+
/*
* A trick to suppress uninitialized variable warning without generating any
* code
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
index 974f5b7..94dea3f 100644
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -2,8 +2,12 @@
#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
#endif
-/* These definitions are for GCC v4.x. */
-#include <linux/compiler-gcc.h>
+/* GCC 4.1.[01] miscompiles __weak */
+#ifdef __KERNEL__
+# if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
+# error Your version of gcc miscompiles the __weak directive
+# endif
+#endif
#define __used __attribute__((__used__))
#define __must_check __attribute__((warn_unused_result))
@@ -16,7 +20,7 @@
*/
#define uninitialized_var(x) x = x
-#if !(__GNUC__ == 4 && __GNUC_MINOR__ < 3)
+#if __GNUC_MINOR__ >= 3
/* Mark functions as cold. gcc will assume any path leading to a call
to them will be unlikely. This means a lot of manual unlikely()s
are unnecessary now for any paths leading to the usual suspects
@@ -32,4 +36,26 @@
the kernel context */
#define __cold __attribute__((__cold__))
+
+#if __GNUC_MINOR__ >= 5
+/*
+ * Mark a position in code as unreachable. This can be used to
+ * suppress control flow warnings after asm blocks that transfer
+ * control elsewhere.
+ *
+ * Early snapshots of gcc 4.5 don't support this and we can't detect
+ * this in the preprocessor, but we can live with this because they're
+ * unreleased. Really, we need to have autoconf for the kernel.
+ */
+#define unreachable() __builtin_unreachable()
+#endif
+
+#endif
+
+#if __GNUC_MINOR__ > 0
+#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
+#endif
+#if __GNUC_MINOR__ >= 4
+#define __compiletime_warning(message) __attribute__((warning(message)))
+#define __compiletime_error(message) __attribute__((error(message)))
#endif
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index c8bd2da..5be3dab 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -36,14 +36,12 @@ extern void __chk_io_ptr(const volatile void __iomem *);
#ifdef __KERNEL__
-#if __GNUC__ >= 4
-# include <linux/compiler-gcc4.h>
-#elif __GNUC__ == 3 && __GNUC_MINOR__ >= 2
-# include <linux/compiler-gcc3.h>
-#else
-# error Sorry, your compiler is too old/not recognized.
+#ifdef __GNUC__
+#include <linux/compiler-gcc.h>
#endif
+#define notrace __attribute__((no_instrument_function))
+
/* Intel compiler defines __GNUC__. So we will overwrite implementations
* coming from above header files here
*/
@@ -57,14 +55,100 @@ extern void __chk_io_ptr(const volatile void __iomem *);
* specific implementations come from the above header files
*/
-#define likely(x) __builtin_expect(!!(x), 1)
-#define unlikely(x) __builtin_expect(!!(x), 0)
+struct ftrace_branch_data {
+ const char *func;
+ const char *file;
+ unsigned line;
+ union {
+ struct {
+ unsigned long correct;
+ unsigned long incorrect;
+ };
+ struct {
+ unsigned long miss;
+ unsigned long hit;
+ };
+ unsigned long miss_hit[2];
+ };
+};
+
+/*
+ * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
+ * to disable branch tracing on a per file basis.
+ */
+#if defined(CONFIG_TRACE_BRANCH_PROFILING) \
+ && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
+void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+
+#define likely_notrace(x) __builtin_expect(!!(x), 1)
+#define unlikely_notrace(x) __builtin_expect(!!(x), 0)
+
+#define __branch_check__(x, expect) ({ \
+ int ______r; \
+ static struct ftrace_branch_data \
+ __attribute__((__aligned__(4))) \
+ __attribute__((section("_ftrace_annotated_branch"))) \
+ ______f = { \
+ .func = __func__, \
+ .file = __FILE__, \
+ .line = __LINE__, \
+ }; \
+ ______r = likely_notrace(x); \
+ ftrace_likely_update(&______f, ______r, expect); \
+ ______r; \
+ })
+
+/*
+ * Using __builtin_constant_p(x) to ignore cases where the return
+ * value is always the same. This idea is taken from a similar patch
+ * written by Daniel Walker.
+ */
+# ifndef likely
+# define likely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1))
+# endif
+# ifndef unlikely
+# define unlikely(x) (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
+# endif
+
+#ifdef CONFIG_PROFILE_ALL_BRANCHES
+/*
+ * "Define 'is'", Bill Clinton
+ * "Define 'if'", Steven Rostedt
+ */
+#define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
+#define __trace_if(cond) \
+ if (__builtin_constant_p((cond)) ? !!(cond) : \
+ ({ \
+ int ______r; \
+ static struct ftrace_branch_data \
+ __attribute__((__aligned__(4))) \
+ __attribute__((section("_ftrace_branch"))) \
+ ______f = { \
+ .func = __func__, \
+ .file = __FILE__, \
+ .line = __LINE__, \
+ }; \
+ ______r = !!(cond); \
+ ______f.miss_hit[______r]++; \
+ ______r; \
+ }))
+#endif /* CONFIG_PROFILE_ALL_BRANCHES */
+
+#else
+# define likely(x) __builtin_expect(!!(x), 1)
+# define unlikely(x) __builtin_expect(!!(x), 0)
+#endif
/* Optimization barrier */
#ifndef barrier
# define barrier() __memory_barrier()
#endif
+/* Unreachable code */
+#ifndef unreachable
+# define unreachable() do { } while (1)
+#endif
+
#ifndef RELOC_HIDE
# define RELOC_HIDE(ptr, off) \
({ unsigned long __ptr; \
@@ -134,6 +218,10 @@ extern void __chk_io_ptr(const volatile void __iomem *);
# define __maybe_unused /* unimplemented */
#endif
+#ifndef __always_unused
+# define __always_unused /* unimplemented */
+#endif
+
#ifndef noinline
#define noinline
#endif
@@ -182,6 +270,22 @@ extern void __chk_io_ptr(const volatile void __iomem *);
# define __section(S) __attribute__ ((__section__(#S)))
#endif
+/* Are two types/vars the same type (ignoring qualifiers)? */
+#ifndef __same_type
+# define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
+#endif
+
+/* Compile time object size, -1 for unknown */
+#ifndef __compiletime_object_size
+# define __compiletime_object_size(obj) -1
+#endif
+#ifndef __compiletime_warning
+# define __compiletime_warning(message)
+#endif
+#ifndef __compiletime_error
+# define __compiletime_error(message)
+#endif
+
/*
* Prevent the compiler from merging or refetching accesses. The compiler
* is also forbidden from reordering successive instances of ACCESS_ONCE(),
@@ -190,7 +294,9 @@ extern void __chk_io_ptr(const volatile void __iomem *);
* ACCESS_ONCE() in different C statements.
*
* This macro does absolutely -nothing- to prevent the CPU from reordering,
- * merging, or refetching absolutely anything at any time.
+ * merging, or refetching absolutely anything at any time. Its main intended
+ * use is to mediate communication between process-level code and irq/NMI
+ * handlers, all running on the same CPU.
*/
#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
--
1.6.6.2
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