include/linux/kernel.h

   1 #ifndef _LINUX_KERNEL_H
   2 #define _LINUX_KERNEL_H
   3
   4 /*
   5  * 'kernel.h' contains some often-used function prototypes etc
   6  */
   7
   8 #ifdef __KERNEL__
   9
  10 #include <stdarg.h>
  11 #include <linux/linkage.h>
  12 #include <linux/stddef.h>
  13 #include <linux/types.h>
  14 #include <linux/compiler.h>
  15 #include <linux/bitops.h>
  16 #include <linux/log2.h>
  17 #include <linux/typecheck.h>
  18 #include <linux/ratelimit.h>
  19 #include <linux/dynamic_debug.h>
  20 #include <asm/byteorder.h>
  21 #include <asm/bug.h>
  22
  23 extern const char linux_banner[];
  24 extern const char linux_proc_banner[];
  25
  26 #define USHORT_MAX      ((u16)(~0U))
  27 #define SHORT_MAX       ((s16)(USHORT_MAX>>1))
  28 #define SHORT_MIN       (-SHORT_MAX - 1)
  29 #define INT_MAX         ((int)(~0U>>1))
  30 #define INT_MIN         (-INT_MAX - 1)
  31 #define UINT_MAX        (~0U)
  32 #define LONG_MAX        ((long)(~0UL>>1))
  33 #define LONG_MIN        (-LONG_MAX - 1)
  34 #define ULONG_MAX       (~0UL)
  35 #define LLONG_MAX       ((long long)(~0ULL>>1))
  36 #define LLONG_MIN       (-LLONG_MAX - 1)
  37 #define ULLONG_MAX      (~0ULL)
  38
  39 #define STACK_MAGIC     0xdeadbeef
  40
  41 #define ALIGN(x,a)              __ALIGN_MASK(x,(typeof(x))(a)-1)
  42 #define __ALIGN_MASK(x,mask)    (((x)+(mask))&~(mask))
  43 #define PTR_ALIGN(p, a)         ((typeof(p))ALIGN((unsigned long)(p), (a)))
  44 #define IS_ALIGNED(x, a)                (((x) & ((typeof(x))(a) - 1)) == 0)
  45
  46 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  47
  48 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  49 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  50 #define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y))
  51 #define DIV_ROUND_CLOSEST(x, divisor)(                  \
  52 {                                                       \
  53         typeof(divisor) __divisor = divisor;            \
  54         (((x) + ((__divisor) / 2)) / (__divisor));      \
  55 }                                                       \
  56 )
  57
  58 #define _RET_IP_                (unsigned long)__builtin_return_address(0)
  59 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
  60
  61 #ifdef CONFIG_LBDAF
  62 # include <asm/div64.h>
  63 # define sector_div(a, b) do_div(a, b)
  64 #else
  65 # define sector_div(n, b)( \
  66 { \
  67         int _res; \
  68         _res = (n) % (b); \
  69         (n) /= (b); \
  70         _res; \
  71 } \
  72 )
  73 #endif
  74
  75 /**
  76  * upper_32_bits - return bits 32-63 of a number
  77  * @n: the number we're accessing
  78  *
  79  * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
  80  * the "right shift count >= width of type" warning when that quantity is
  81  * 32-bits.
  82  */
  83 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
  84
  85 /**
  86  * lower_32_bits - return bits 0-31 of a number
  87  * @n: the number we're accessing
  88  */
  89 #define lower_32_bits(n) ((u32)(n))
  90
  91 #define KERN_EMERG      "<0>"   /* system is unusable                   */
  92 #define KERN_ALERT      "<1>"   /* action must be taken immediately     */
  93 #define KERN_CRIT       "<2>"   /* critical conditions                  */
  94 #define KERN_ERR        "<3>"   /* error conditions                     */
  95 #define KERN_WARNING    "<4>"   /* warning conditions                   */
  96 #define KERN_NOTICE     "<5>"   /* normal but significant condition     */
  97 #define KERN_INFO       "<6>"   /* informational                        */
  98 #define KERN_DEBUG      "<7>"   /* debug-level messages                 */
  99
 100 /* Use the default kernel loglevel */
 101 #define KERN_DEFAULT    "<d>"
 102 /*
 103  * Annotation for a "continued" line of log printout (only done after a
 104  * line that had no enclosing \n). Only to be used by core/arch code
 105  * during early bootup (a continued line is not SMP-safe otherwise).
 106  */
 107 #define KERN_CONT       "<c>"
 108
 109 extern int console_printk[];
 110
 111 #define console_loglevel (console_printk[0])
 112 #define default_message_loglevel (console_printk[1])
 113 #define minimum_console_loglevel (console_printk[2])
 114 #define default_console_loglevel (console_printk[3])
 115
 116 struct completion;
 117 struct pt_regs;
 118 struct user;
 119
 120 #ifdef CONFIG_PREEMPT_VOLUNTARY
 121 extern int _cond_resched(void);
 122 # define might_resched() _cond_resched()
 123 #else
 124 # define might_resched() do { } while (0)
 125 #endif
 126
 127 #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
 128   void __might_sleep(char *file, int line, int preempt_offset);
 129 /**
 130  * might_sleep - annotation for functions that can sleep
 131  *
 132  * this macro will print a stack trace if it is executed in an atomic
 133  * context (spinlock, irq-handler, ...).
 134  *
 135  * This is a useful debugging help to be able to catch problems early and not
 136  * be bitten later when the calling function happens to sleep when it is not
 137  * supposed to.
 138  */
 139 # define might_sleep() \
 140         do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 141 #else
 142   static inline void __might_sleep(char *file, int line, int preempt_offset) { }
 143 # define might_sleep() do { might_resched(); } while (0)
 144 #endif
 145
 146 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 147
 148 #define abs(x) ({                               \
 149                 long __x = (x);                 \
 150                 (__x < 0) ? -__x : __x;         \
 151         })
 152
 153 #ifdef CONFIG_PROVE_LOCKING
 154 void might_fault(void);
 155 #else
 156 static inline void might_fault(void)
 157 {
 158         might_sleep();
 159 }
 160 #endif
 161
 162 extern struct atomic_notifier_head panic_notifier_list;
 163 extern long (*panic_blink)(long time);
 164 NORET_TYPE void panic(const char * fmt, ...)
 165         __attribute__ ((NORET_AND format (printf, 1, 2))) __cold;
 166 extern void oops_enter(void);
 167 extern void oops_exit(void);
 168 extern int oops_may_print(void);
 169 NORET_TYPE void do_exit(long error_code)
 170         ATTRIB_NORET;
 171 NORET_TYPE void complete_and_exit(struct completion *, long)
 172         ATTRIB_NORET;
 173 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 174 extern long simple_strtol(const char *,char **,unsigned int);
 175 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 176 extern long long simple_strtoll(const char *,char **,unsigned int);
 177 extern int strict_strtoul(const char *, unsigned int, unsigned long *);
 178 extern int strict_strtol(const char *, unsigned int, long *);
 179 extern int strict_strtoull(const char *, unsigned int, unsigned long long *);
 180 extern int strict_strtoll(const char *, unsigned int, long long *);
 181 extern int sprintf(char * buf, const char * fmt, ...)
 182         __attribute__ ((format (printf, 2, 3)));
 183 extern int vsprintf(char *buf, const char *, va_list)
 184         __attribute__ ((format (printf, 2, 0)));
 185 extern int snprintf(char * buf, size_t size, const char * fmt, ...)
 186         __attribute__ ((format (printf, 3, 4)));
 187 extern int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 188         __attribute__ ((format (printf, 3, 0)));
 189 extern int scnprintf(char * buf, size_t size, const char * fmt, ...)
 190         __attribute__ ((format (printf, 3, 4)));
 191 extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 192         __attribute__ ((format (printf, 3, 0)));
 193 extern char *kasprintf(gfp_t gfp, const char *fmt, ...)
 194         __attribute__ ((format (printf, 2, 3)));
 195 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 196
 197 extern int sscanf(const char *, const char *, ...)
 198         __attribute__ ((format (scanf, 2, 3)));
 199 extern int vsscanf(const char *, const char *, va_list)
 200         __attribute__ ((format (scanf, 2, 0)));
 201
 202 extern int get_option(char **str, int *pint);
 203 extern char *get_options(const char *str, int nints, int *ints);
 204 extern unsigned long long memparse(const char *ptr, char **retptr);
 205
 206 extern int core_kernel_text(unsigned long addr);
 207 extern int __kernel_text_address(unsigned long addr);
 208 extern int kernel_text_address(unsigned long addr);
 209 extern int func_ptr_is_kernel_text(void *ptr);
 210
 211 struct pid;
 212 extern struct pid *session_of_pgrp(struct pid *pgrp);
 213
 214 /*
 215  * FW_BUG
 216  * Add this to a message where you are sure the firmware is buggy or behaves
 217  * really stupid or out of spec. Be aware that the responsible BIOS developer
 218  * should be able to fix this issue or at least get a concrete idea of the
 219  * problem by reading your message without the need of looking at the kernel
 220  * code.
 221  *
 222  * Use it for definite and high priority BIOS bugs.
 223  *
 224  * FW_WARN
 225  * Use it for not that clear (e.g. could the kernel messed up things already?)
 226  * and medium priority BIOS bugs.
 227  *
 228  * FW_INFO
 229  * Use this one if you want to tell the user or vendor about something
 230  * suspicious, but generally harmless related to the firmware.
 231  *
 232  * Use it for information or very low priority BIOS bugs.
 233  */
 234 #define FW_BUG          "[Firmware Bug]: "
 235 #define FW_WARN         "[Firmware Warn]: "
 236 #define FW_INFO         "[Firmware Info]: "
 237
 238 #ifdef CONFIG_PRINTK
 239 asmlinkage int vprintk(const char *fmt, va_list args)
 240         __attribute__ ((format (printf, 1, 0)));
 241 asmlinkage int printk(const char * fmt, ...)
 242         __attribute__ ((format (printf, 1, 2))) __cold;
 243
 244 extern struct ratelimit_state printk_ratelimit_state;
 245 extern int printk_ratelimit(void);
 246 extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 247                                    unsigned int interval_msec);
 248
 249 extern int printk_delay_msec;
 250
 251 /*
 252  * Print a one-time message (analogous to WARN_ONCE() et al):
 253  */
 254 #define printk_once(x...) ({                    \
 255         static bool __print_once = true;        \
 256                                                 \
 257         if (__print_once) {                     \
 258                 __print_once = false;           \
 259                 printk(x);                      \
 260         }                                       \
 261 })
 262
 263 void log_buf_kexec_setup(void);
 264 #else
 265 static inline int vprintk(const char *s, va_list args)
 266         __attribute__ ((format (printf, 1, 0)));
 267 static inline int vprintk(const char *s, va_list args) { return 0; }
 268 static inline int printk(const char *s, ...)
 269         __attribute__ ((format (printf, 1, 2)));
 270 static inline int __cold printk(const char *s, ...) { return 0; }
 271 static inline int printk_ratelimit(void) { return 0; }
 272 static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies, \
 273                                           unsigned int interval_msec)   \
 274                 { return false; }
 275
 276 /* No effect, but we still get type checking even in the !PRINTK case: */
 277 #define printk_once(x...) printk(x)
 278
 279 static inline void log_buf_kexec_setup(void)
 280 {
 281 }
 282 #endif
 283
 284 extern int printk_needs_cpu(int cpu);
 285 extern void printk_tick(void);
 286
 287 extern void asmlinkage __attribute__((format(printf, 1, 2)))
 288         early_printk(const char *fmt, ...);
 289
 290 unsigned long int_sqrt(unsigned long);
 291
 292 static inline void console_silent(void)
 293 {
 294         console_loglevel = 0;
 295 }
 296
 297 static inline void console_verbose(void)
 298 {
 299         if (console_loglevel)
 300                 console_loglevel = 15;
 301 }
 302
 303 extern void bust_spinlocks(int yes);
 304 extern void wake_up_klogd(void);
 305 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 306 extern int panic_timeout;
 307 extern int panic_on_oops;
 308 extern int panic_on_unrecovered_nmi;
 309 extern int panic_on_io_nmi;
 310 extern const char *print_tainted(void);
 311 extern void add_taint(unsigned flag);
 312 extern int test_taint(unsigned flag);
 313 extern unsigned long get_taint(void);
 314 extern int root_mountflags;
 315
 316 /* Values used for system_state */
 317 extern enum system_states {
 318         SYSTEM_BOOTING,
 319         SYSTEM_RUNNING,
 320         SYSTEM_HALT,
 321         SYSTEM_POWER_OFF,
 322         SYSTEM_RESTART,
 323         SYSTEM_SUSPEND_DISK,
 324 } system_state;
 325
 326 #define TAINT_PROPRIETARY_MODULE        0
 327 #define TAINT_FORCED_MODULE             1
 328 #define TAINT_UNSAFE_SMP                2
 329 #define TAINT_FORCED_RMMOD              3
 330 #define TAINT_MACHINE_CHECK             4
 331 #define TAINT_BAD_PAGE                  5
 332 #define TAINT_USER                      6
 333 #define TAINT_DIE                       7
 334 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
 335 #define TAINT_WARN                      9
 336 #define TAINT_CRAP                      10
 337
 338 extern void dump_stack(void) __cold;
 339
 340 enum {
 341         DUMP_PREFIX_NONE,
 342         DUMP_PREFIX_ADDRESS,
 343         DUMP_PREFIX_OFFSET
 344 };
 345 extern void hex_dump_to_buffer(const void *buf, size_t len,
 346                                 int rowsize, int groupsize,
 347                                 char *linebuf, size_t linebuflen, bool ascii);
 348 extern void print_hex_dump(const char *level, const char *prefix_str,
 349                                 int prefix_type, int rowsize, int groupsize,
 350                                 const void *buf, size_t len, bool ascii);
 351 extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 352                         const void *buf, size_t len);
 353
 354 extern const char hex_asc[];
 355 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 356 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 357
 358 static inline char *pack_hex_byte(char *buf, u8 byte)
 359 {
 360         *buf++ = hex_asc_hi(byte);
 361         *buf++ = hex_asc_lo(byte);
 362         return buf;
 363 }
 364
 365 #ifndef pr_fmt
 366 #define pr_fmt(fmt) fmt
 367 #endif
 368
 369 #define pr_emerg(fmt, ...) \
 370         printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
 371 #define pr_alert(fmt, ...) \
 372         printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
 373 #define pr_crit(fmt, ...) \
 374         printk(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
 375 #define pr_err(fmt, ...) \
 376         printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
 377 #define pr_warning(fmt, ...) \
 378         printk(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
 379 #define pr_notice(fmt, ...) \
 380         printk(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
 381 #define pr_info(fmt, ...) \
 382         printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
 383 #define pr_cont(fmt, ...) \
 384         printk(KERN_CONT fmt, ##__VA_ARGS__)
 385
 386 /* pr_devel() should produce zero code unless DEBUG is defined */
 387 #ifdef DEBUG
 388 #define pr_devel(fmt, ...) \
 389         printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 390 #else
 391 #define pr_devel(fmt, ...) \
 392         ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; })
 393 #endif
 394
 395 /* If you are writing a driver, please use dev_dbg instead */
 396 #if defined(DEBUG)
 397 #define pr_debug(fmt, ...) \
 398         printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 399 #elif defined(CONFIG_DYNAMIC_DEBUG)
 400 /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
 401 #define pr_debug(fmt, ...) do { \
 402         dynamic_pr_debug(fmt, ##__VA_ARGS__); \
 403         } while (0)
 404 #else
 405 #define pr_debug(fmt, ...) \
 406         ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; })
 407 #endif
 408
 409 /*
 410  * General tracing related utility functions - trace_printk(),
 411  * tracing_on/tracing_off and tracing_start()/tracing_stop
 412  *
 413  * Use tracing_on/tracing_off when you want to quickly turn on or off
 414  * tracing. It simply enables or disables the recording of the trace events.
 415  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 416  * file, which gives a means for the kernel and userspace to interact.
 417  * Place a tracing_off() in the kernel where you want tracing to end.
 418  * From user space, examine the trace, and then echo 1 > tracing_on
 419  * to continue tracing.
 420  *
 421  * tracing_stop/tracing_start has slightly more overhead. It is used
 422  * by things like suspend to ram where disabling the recording of the
 423  * trace is not enough, but tracing must actually stop because things
 424  * like calling smp_processor_id() may crash the system.
 425  *
 426  * Most likely, you want to use tracing_on/tracing_off.
 427  */
 428 #ifdef CONFIG_RING_BUFFER
 429 void tracing_on(void);
 430 void tracing_off(void);
 431 /* trace_off_permanent stops recording with no way to bring it back */
 432 void tracing_off_permanent(void);
 433 int tracing_is_on(void);
 434 #else
 435 static inline void tracing_on(void) { }
 436 static inline void tracing_off(void) { }
 437 static inline void tracing_off_permanent(void) { }
 438 static inline int tracing_is_on(void) { return 0; }
 439 #endif
 440 #ifdef CONFIG_TRACING
 441 extern void tracing_start(void);
 442 extern void tracing_stop(void);
 443 extern void ftrace_off_permanent(void);
 444
 445 extern void
 446 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 447
 448 static inline void __attribute__ ((format (printf, 1, 2)))
 449 ____trace_printk_check_format(const char *fmt, ...)
 450 {
 451 }
 452 #define __trace_printk_check_format(fmt, args...)                       \
 453 do {                                                                    \
 454         if (0)                                                          \
 455                 ____trace_printk_check_format(fmt, ##args);             \
 456 } while (0)
 457
 458 /**
 459  * trace_printk - printf formatting in the ftrace buffer
 460  * @fmt: the printf format for printing
 461  *
 462  * Note: __trace_printk is an internal function for trace_printk and
 463  *       the @ip is passed in via the trace_printk macro.
 464  *
 465  * This function allows a kernel developer to debug fast path sections
 466  * that printk is not appropriate for. By scattering in various
 467  * printk like tracing in the code, a developer can quickly see
 468  * where problems are occurring.
 469  *
 470  * This is intended as a debugging tool for the developer only.
 471  * Please refrain from leaving trace_printks scattered around in
 472  * your code.
 473  */
 474
 475 #define trace_printk(fmt, args...)                                      \
 476 do {                                                                    \
 477         __trace_printk_check_format(fmt, ##args);                       \
 478         if (__builtin_constant_p(fmt)) {                                \
 479                 static const char *trace_printk_fmt                     \
 480                   __attribute__((section("__trace_printk_fmt"))) =      \
 481                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 482                                                                         \
 483                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 484         } else                                                          \
 485                 __trace_printk(_THIS_IP_, fmt, ##args);         \
 486 } while (0)
 487
 488 extern int
 489 __trace_bprintk(unsigned long ip, const char *fmt, ...)
 490         __attribute__ ((format (printf, 2, 3)));
 491
 492 extern int
 493 __trace_printk(unsigned long ip, const char *fmt, ...)
 494         __attribute__ ((format (printf, 2, 3)));
 495
 496 /*
 497  * The double __builtin_constant_p is because gcc will give us an error
 498  * if we try to allocate the static variable to fmt if it is not a
 499  * constant. Even with the outer if statement.
 500  */
 501 #define ftrace_vprintk(fmt, vargs)                                      \
 502 do {                                                                    \
 503         if (__builtin_constant_p(fmt)) {                                \
 504                 static const char *trace_printk_fmt                     \
 505                   __attribute__((section("__trace_printk_fmt"))) =      \
 506                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 507                                                                         \
 508                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 509         } else                                                          \
 510                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 511 } while (0)
 512
 513 extern int
 514 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 515
 516 extern int
 517 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 518
 519 extern void ftrace_dump(void);
 520 #else
 521 static inline void
 522 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 523 static inline int
 524 trace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
 525
 526 static inline void tracing_start(void) { }
 527 static inline void tracing_stop(void) { }
 528 static inline void ftrace_off_permanent(void) { }
 529 static inline int
 530 trace_printk(const char *fmt, ...)
 531 {
 532         return 0;
 533 }
 534 static inline int
 535 ftrace_vprintk(const char *fmt, va_list ap)
 536 {
 537         return 0;
 538 }
 539 static inline void ftrace_dump(void) { }
 540 #endif /* CONFIG_TRACING */
 541
 542 /*
 543  *      Display an IP address in readable format.
 544  */
 545
 546 #define NIPQUAD(addr) \
 547         ((unsigned char *)&addr)[0], \
 548         ((unsigned char *)&addr)[1], \
 549         ((unsigned char *)&addr)[2], \
 550         ((unsigned char *)&addr)[3]
 551 #define NIPQUAD_FMT "%u.%u.%u.%u"
 552
 553 /*
 554  * min()/max()/clamp() macros that also do
 555  * strict type-checking.. See the
 556  * "unnecessary" pointer comparison.
 557  */
 558 #define min(x, y) ({                            \
 559         typeof(x) _min1 = (x);                  \
 560         typeof(y) _min2 = (y);                  \
 561         (void) (&_min1 == &_min2);              \
 562         _min1 < _min2 ? _min1 : _min2; })
 563
 564 #define max(x, y) ({                            \
 565         typeof(x) _max1 = (x);                  \
 566         typeof(y) _max2 = (y);                  \
 567         (void) (&_max1 == &_max2);              \
 568         _max1 > _max2 ? _max1 : _max2; })
 569
 570 /**
 571  * clamp - return a value clamped to a given range with strict typechecking
 572  * @val: current value
 573  * @min: minimum allowable value
 574  * @max: maximum allowable value
 575  *
 576  * This macro does strict typechecking of min/max to make sure they are of the
 577  * same type as val.  See the unnecessary pointer comparisons.
 578  */
 579 #define clamp(val, min, max) ({                 \
 580         typeof(val) __val = (val);              \
 581         typeof(min) __min = (min);              \
 582         typeof(max) __max = (max);              \
 583         (void) (&__val == &__min);              \
 584         (void) (&__val == &__max);              \
 585         __val = __val < __min ? __min: __val;   \
 586         __val > __max ? __max: __val; })
 587
 588 /*
 589  * ..and if you can't take the strict
 590  * types, you can specify one yourself.
 591  *
 592  * Or not use min/max/clamp at all, of course.
 593  */
 594 #define min_t(type, x, y) ({                    \
 595         type __min1 = (x);                      \
 596         type __min2 = (y);                      \
 597         __min1 < __min2 ? __min1: __min2; })
 598
 599 #define max_t(type, x, y) ({                    \
 600         type __max1 = (x);                      \
 601         type __max2 = (y);                      \
 602         __max1 > __max2 ? __max1: __max2; })
 603
 604 /**
 605  * clamp_t - return a value clamped to a given range using a given type
 606  * @type: the type of variable to use
 607  * @val: current value
 608  * @min: minimum allowable value
 609  * @max: maximum allowable value
 610  *
 611  * This macro does no typechecking and uses temporary variables of type
 612  * 'type' to make all the comparisons.
 613  */
 614 #define clamp_t(type, val, min, max) ({         \
 615         type __val = (val);                     \
 616         type __min = (min);                     \
 617         type __max = (max);                     \
 618         __val = __val < __min ? __min: __val;   \
 619         __val > __max ? __max: __val; })
 620
 621 /**
 622  * clamp_val - return a value clamped to a given range using val's type
 623  * @val: current value
 624  * @min: minimum allowable value
 625  * @max: maximum allowable value
 626  *
 627  * This macro does no typechecking and uses temporary variables of whatever
 628  * type the input argument 'val' is.  This is useful when val is an unsigned
 629  * type and min and max are literals that will otherwise be assigned a signed
 630  * integer type.
 631  */
 632 #define clamp_val(val, min, max) ({             \
 633         typeof(val) __val = (val);              \
 634         typeof(val) __min = (min);              \
 635         typeof(val) __max = (max);              \
 636         __val = __val < __min ? __min: __val;   \
 637         __val > __max ? __max: __val; })
 638
 639
 640 /*
 641  * swap - swap value of @a and @b
 642  */
 643 #define swap(a, b) \
 644         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 645
 646 /**
 647  * container_of - cast a member of a structure out to the containing structure
 648  * @ptr:        the pointer to the member.
 649  * @type:       the type of the container struct this is embedded in.
 650  * @member:     the name of the member within the struct.
 651  *
 652  */
 653 #define container_of(ptr, type, member) ({                      \
 654         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 655         (type *)( (char *)__mptr - offsetof(type,member) );})
 656
 657 struct sysinfo;
 658 extern int do_sysinfo(struct sysinfo *info);
 659
 660 #endif /* __KERNEL__ */
 661
 662 #ifndef __EXPORTED_HEADERS__
 663 #ifndef __KERNEL__
 664 #warning Attempt to use kernel headers from user space, see http://kernelnewbies.org/KernelHeaders
 665 #endif /* __KERNEL__ */
 666 #endif /* __EXPORTED_HEADERS__ */
 667
 668 #define SI_LOAD_SHIFT   16
 669 struct sysinfo {
 670         long uptime;                    /* Seconds since boot */
 671         unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 672         unsigned long totalram;         /* Total usable main memory size */
 673         unsigned long freeram;          /* Available memory size */
 674         unsigned long sharedram;        /* Amount of shared memory */
 675         unsigned long bufferram;        /* Memory used by buffers */
 676         unsigned long totalswap;        /* Total swap space size */
 677         unsigned long freeswap;         /* swap space still available */
 678         unsigned short procs;           /* Number of current processes */
 679         unsigned short pad;             /* explicit padding for m68k */
 680         unsigned long totalhigh;        /* Total high memory size */
 681         unsigned long freehigh;         /* Available high memory size */
 682         unsigned int mem_unit;          /* Memory unit size in bytes */
 683         char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 684 };
 685
 686 /* Force a compilation error if condition is true */
 687 #define BUILD_BUG_ON(condition) ((void)BUILD_BUG_ON_ZERO(condition))
 688
 689 /* Force a compilation error if condition is constant and true */
 690 #define MAYBE_BUILD_BUG_ON(cond) ((void)sizeof(char[1 - 2 * !!(cond)]))
 691
 692 /* Force a compilation error if condition is true, but also produce a
 693    result (of value 0 and type size_t), so the expression can be used
 694    e.g. in a structure initializer (or where-ever else comma expressions
 695    aren't permitted). */
 696 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 697 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
 698
 699 /* Trap pasters of __FUNCTION__ at compile-time */
 700 #define __FUNCTION__ (__func__)
 701
 702 /* This helps us to avoid #ifdef CONFIG_NUMA */
 703 #ifdef CONFIG_NUMA
 704 #define NUMA_BUILD 1
 705 #else
 706 #define NUMA_BUILD 0
 707 #endif
 708
 709 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 710 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 711 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 712 #endif
 713
 714 #endif