release/src-rt-6.x.4708/linux/linux-2.6.36/include/linux/compiler.h

   1 #ifndef __LINUX_COMPILER_H
   2 #define __LINUX_COMPILER_H
   3
   4 #ifndef __ASSEMBLY__
   5
   6 #ifdef __CHECKER__
   7 # define __user         __attribute__((noderef, address_space(1)))
   8 # define __kernel       __attribute__((address_space(0)))
   9 # define __safe         __attribute__((safe))
  10 # define __force        __attribute__((force))
  11 # define __nocast       __attribute__((nocast))
  12 # define __iomem        __attribute__((noderef, address_space(2)))
  13 # define __acquires(x)  __attribute__((context(x,0,1)))
  14 # define __releases(x)  __attribute__((context(x,1,0)))
  15 # define __acquire(x)   __context__(x,1)
  16 # define __release(x)   __context__(x,-1)
  17 # define __cond_lock(x,c)       ((c) ? ({ __acquire(x); 1; }) : 0)
  18 # define __percpu       __attribute__((noderef, address_space(3)))
  19 # define __rcu
  20 extern void __chk_user_ptr(const volatile void __user *);
  21 extern void __chk_io_ptr(const volatile void __iomem *);
  22 #else
  23 # define __user
  24 # define __kernel
  25 # define __safe
  26 # define __force
  27 # define __nocast
  28 # define __iomem
  29 # define __chk_user_ptr(x) (void)0
  30 # define __chk_io_ptr(x) (void)0
  31 # define __builtin_warning(x, y...) (1)
  32 # define __acquires(x)
  33 # define __releases(x)
  34 # define __acquire(x) (void)0
  35 # define __release(x) (void)0
  36 # define __cond_lock(x,c) (c)
  37 # define __percpu
  38 # define __rcu
  39 #endif
  40
  41 #ifdef __KERNEL__
  42
  43 #ifdef __GNUC__
  44 #include <linux/compiler-gcc.h>
  45 #endif
  46
  47 #define notrace __attribute__((no_instrument_function))
  48
  49 /* Intel compiler defines __GNUC__. So we will overwrite implementations
  50  * coming from above header files here
  51  */
  52 #ifdef __INTEL_COMPILER
  53 # include <linux/compiler-intel.h>
  54 #endif
  55
  56 /*
  57  * Generic compiler-dependent macros required for kernel
  58  * build go below this comment. Actual compiler/compiler version
  59  * specific implementations come from the above header files
  60  */
  61
  62 struct ftrace_branch_data {
  63         const char *func;
  64         const char *file;
  65         unsigned line;
  66         union {
  67                 struct {
  68                         unsigned long correct;
  69                         unsigned long incorrect;
  70                 };
  71                 struct {
  72                         unsigned long miss;
  73                         unsigned long hit;
  74                 };
  75                 unsigned long miss_hit[2];
  76         };
  77 };
  78
  79 /*
  80  * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
  81  * to disable branch tracing on a per file basis.
  82  */
  83 #if defined(CONFIG_TRACE_BRANCH_PROFILING) && !defined(DISABLE_BRANCH_PROFILING) && \
  84         !defined(__CHECKER__)
  85 void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
  86
  87 #define likely_notrace(x)       __builtin_expect(!!(x), 1)
  88 #define unlikely_notrace(x)     __builtin_expect(!!(x), 0)
  89
  90 #define __branch_check__(x, expect) ({                                  \
  91                         int ______r;                                    \
  92                         static struct ftrace_branch_data                \
  93                                 __attribute__((__aligned__(4)))         \
  94                                 __attribute__((section("_ftrace_annotated_branch"))) \
  95                                 ______f = {                             \
  96                                 .func = __func__,                       \
  97                                 .file = __FILE__,                       \
  98                                 .line = __LINE__,                       \
  99                         };                                              \
 100                         ______r = likely_notrace(x);                    \
 101                         ftrace_likely_update(&______f, ______r, expect); \
 102                         ______r;                                        \
 103                 })
 104
 105 /*
 106  * Using __builtin_constant_p(x) to ignore cases where the return
 107  * value is always the same.  This idea is taken from a similar patch
 108  * written by Daniel Walker.
 109  */
 110 # ifndef likely
 111 #  define likely(x)     (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 1))
 112 # endif
 113 # ifndef unlikely
 114 #  define unlikely(x)   (__builtin_constant_p(x) ? !!(x) : __branch_check__(x, 0))
 115 # endif
 116
 117 #ifdef CONFIG_PROFILE_ALL_BRANCHES
 118 /*
 119  * "Define 'is'", Bill Clinton
 120  * "Define 'if'", Steven Rostedt
 121  */
 122 #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
 123 #define __trace_if(cond) \
 124         if (__builtin_constant_p((cond)) ? !!(cond) :                   \
 125         ({                                                              \
 126                 int ______r;                                            \
 127                 static struct ftrace_branch_data                        \
 128                         __attribute__((__aligned__(4)))                 \
 129                         __attribute__((section("_ftrace_branch")))      \
 130                         ______f = {                                     \
 131                                 .func = __func__,                       \
 132                                 .file = __FILE__,                       \
 133                                 .line = __LINE__,                       \
 134                         };                                              \
 135                 ______r = !!(cond);                                     \
 136                 ______f.miss_hit[______r]++;                                    \
 137                 ______r;                                                \
 138         }))
 139 #endif /* CONFIG_PROFILE_ALL_BRANCHES */
 140
 141 #else
 142 # define likely(x)      __builtin_expect(!!(x), 1)
 143 # define unlikely(x)    __builtin_expect(!!(x), 0)
 144 #endif
 145
 146 /* Optimization barrier */
 147 #ifndef barrier
 148 # define barrier() __memory_barrier()
 149 #endif
 150
 151 /* Unreachable code */
 152 #ifndef unreachable
 153 # define unreachable() do { } while (1)
 154 #endif
 155
 156 #ifndef RELOC_HIDE
 157 # define RELOC_HIDE(ptr, off)                                   \
 158   ({ unsigned long __ptr;                                       \
 159      __ptr = (unsigned long) (ptr);                             \
 160     (typeof(ptr)) (__ptr + (off)); })
 161 #endif
 162
 163 #endif /* __KERNEL__ */
 164
 165 #endif /* __ASSEMBLY__ */
 166
 167 #ifdef __KERNEL__
 168 /*
 169  * Allow us to mark functions as 'deprecated' and have gcc emit a nice
 170  * warning for each use, in hopes of speeding the functions removal.
 171  * Usage is:
 172  *              int __deprecated foo(void)
 173  */
 174 #ifndef __deprecated
 175 # define __deprecated           /* unimplemented */
 176 #endif
 177
 178 #ifdef MODULE
 179 #define __deprecated_for_modules __deprecated
 180 #else
 181 #define __deprecated_for_modules
 182 #endif
 183
 184 #ifndef __must_check
 185 #define __must_check
 186 #endif
 187
 188 #ifndef CONFIG_ENABLE_MUST_CHECK
 189 #undef __must_check
 190 #define __must_check
 191 #endif
 192 #ifndef CONFIG_ENABLE_WARN_DEPRECATED
 193 #undef __deprecated
 194 #undef __deprecated_for_modules
 195 #define __deprecated
 196 #define __deprecated_for_modules
 197 #endif
 198
 199 /*
 200  * Allow us to avoid 'defined but not used' warnings on functions and data,
 201  * as well as force them to be emitted to the assembly file.
 202  *
 203  * As of gcc 3.4, static functions that are not marked with attribute((used))
 204  * may be elided from the assembly file.  As of gcc 3.4, static data not so
 205  * marked will not be elided, but this may change in a future gcc version.
 206  *
 207  * NOTE: Because distributions shipped with a backported unit-at-a-time
 208  * compiler in gcc 3.3, we must define __used to be __attribute__((used))
 209  * for gcc >=3.3 instead of 3.4.
 210  *
 211  * In prior versions of gcc, such functions and data would be emitted, but
 212  * would be warned about except with attribute((unused)).
 213  *
 214  * Mark functions that are referenced only in inline assembly as __used so
 215  * the code is emitted even though it appears to be unreferenced.
 216  */
 217 #ifndef __used
 218 # define __used                 /* unimplemented */
 219 #endif
 220
 221 #ifndef __maybe_unused
 222 # define __maybe_unused         /* unimplemented */
 223 #endif
 224
 225 #ifndef __always_unused
 226 # define __always_unused        /* unimplemented */
 227 #endif
 228
 229 #ifndef noinline
 230 #define noinline
 231 #endif
 232
 233 /*
 234  * Rather then using noinline to prevent stack consumption, use
 235  * noinline_for_stack instead.  For documentaiton reasons.
 236  */
 237 #define noinline_for_stack noinline
 238
 239 #ifndef __always_inline
 240 #define __always_inline inline
 241 #endif
 242
 243 #endif /* __KERNEL__ */
 244
 245 /*
 246  * From the GCC manual:
 247  *
 248  * Many functions do not examine any values except their arguments,
 249  * and have no effects except the return value.  Basically this is
 250  * just slightly more strict class than the `pure' attribute above,
 251  * since function is not allowed to read global memory.
 252  *
 253  * Note that a function that has pointer arguments and examines the
 254  * data pointed to must _not_ be declared `const'.  Likewise, a
 255  * function that calls a non-`const' function usually must not be
 256  * `const'.  It does not make sense for a `const' function to return
 257  * `void'.
 258  */
 259 #ifndef __attribute_const__
 260 # define __attribute_const__    /* unimplemented */
 261 #endif
 262
 263 /*
 264  * Tell gcc if a function is cold. The compiler will assume any path
 265  * directly leading to the call is unlikely.
 266  */
 267
 268 #ifndef __cold
 269 #define __cold
 270 #endif
 271
 272 /* Simple shorthand for a section definition */
 273 #ifndef __section
 274 # define __section(S) __attribute__ ((__section__(#S)))
 275 #endif
 276
 277 /* Are two types/vars the same type (ignoring qualifiers)? */
 278 #ifndef __same_type
 279 # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
 280 #endif
 281
 282 /* Compile time object size, -1 for unknown */
 283 #ifndef __compiletime_object_size
 284 # define __compiletime_object_size(obj) -1
 285 #endif
 286 #ifndef __compiletime_warning
 287 # define __compiletime_warning(message)
 288 #endif
 289 #ifndef __compiletime_error
 290 # define __compiletime_error(message)
 291 #endif
 292
 293 /*
 294  * Prevent the compiler from merging or refetching accesses.  The compiler
 295  * is also forbidden from reordering successive instances of ACCESS_ONCE(),
 296  * but only when the compiler is aware of some particular ordering.  One way
 297  * to make the compiler aware of ordering is to put the two invocations of
 298  * ACCESS_ONCE() in different C statements.
 299  *
 300  * This macro does absolutely -nothing- to prevent the CPU from reordering,
 301  * merging, or refetching absolutely anything at any time.  Its main intended
 302  * use is to mediate communication between process-level code and irq/NMI
 303  * handlers, all running on the same CPU.
 304  */
 305 #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
 306
 307 #endif /* __LINUX_COMPILER_H */