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                 int __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 /*
 250  * Print a one-time message (analogous to WARN_ONCE() et al):
 251  */
 252 #define printk_once(x...) ({                    \
 253         static int __print_once = 1;            \
 254                                                 \
 255         if (__print_once) {                     \
 256                 __print_once = 0;               \
 257                 printk(x);                      \
 258         }                                       \
 259 })
 260
 261 void log_buf_kexec_setup(void);
 262 #else
 263 static inline int vprintk(const char *s, va_list args)
 264         __attribute__ ((format (printf, 1, 0)));
 265 static inline int vprintk(const char *s, va_list args) { return 0; }
 266 static inline int printk(const char *s, ...)
 267         __attribute__ ((format (printf, 1, 2)));
 268 static inline int __cold printk(const char *s, ...) { return 0; }
 269 static inline int printk_ratelimit(void) { return 0; }
 270 static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies, \
 271                                           unsigned int interval_msec)   \
 272                 { return false; }
 273
 274 /* No effect, but we still get type checking even in the !PRINTK case: */
 275 #define printk_once(x...) printk(x)
 276
 277 static inline void log_buf_kexec_setup(void)
 278 {
 279 }
 280 #endif
 281
 282 extern int printk_needs_cpu(int cpu);
 283 extern void printk_tick(void);
 284
 285 extern void asmlinkage __attribute__((format(printf, 1, 2)))
 286         early_printk(const char *fmt, ...);
 287
 288 unsigned long int_sqrt(unsigned long);
 289
 290 static inline void console_silent(void)
 291 {
 292         console_loglevel = 0;
 293 }
 294
 295 static inline void console_verbose(void)
 296 {
 297         if (console_loglevel)
 298                 console_loglevel = 15;
 299 }
 300
 301 extern void bust_spinlocks(int yes);
 302 extern void wake_up_klogd(void);
 303 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 304 extern int panic_timeout;
 305 extern int panic_on_oops;
 306 extern int panic_on_unrecovered_nmi;
 307 extern int panic_on_io_nmi;
 308 extern const char *print_tainted(void);
 309 extern void add_taint(unsigned flag);
 310 extern int test_taint(unsigned flag);
 311 extern unsigned long get_taint(void);
 312 extern int root_mountflags;
 313
 314 /* Values used for system_state */
 315 extern enum system_states {
 316         SYSTEM_BOOTING,
 317         SYSTEM_RUNNING,
 318         SYSTEM_HALT,
 319         SYSTEM_POWER_OFF,
 320         SYSTEM_RESTART,
 321         SYSTEM_SUSPEND_DISK,
 322 } system_state;
 323
 324 #define TAINT_PROPRIETARY_MODULE        0
 325 #define TAINT_FORCED_MODULE             1
 326 #define TAINT_UNSAFE_SMP                2
 327 #define TAINT_FORCED_RMMOD              3
 328 #define TAINT_MACHINE_CHECK             4
 329 #define TAINT_BAD_PAGE                  5
 330 #define TAINT_USER                      6
 331 #define TAINT_DIE                       7
 332 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
 333 #define TAINT_WARN                      9
 334 #define TAINT_CRAP                      10
 335
 336 extern void dump_stack(void) __cold;
 337
 338 enum {
 339         DUMP_PREFIX_NONE,
 340         DUMP_PREFIX_ADDRESS,
 341         DUMP_PREFIX_OFFSET
 342 };
 343 extern void hex_dump_to_buffer(const void *buf, size_t len,
 344                                 int rowsize, int groupsize,
 345                                 char *linebuf, size_t linebuflen, bool ascii);
 346 extern void print_hex_dump(const char *level, const char *prefix_str,
 347                                 int prefix_type, int rowsize, int groupsize,
 348                                 const void *buf, size_t len, bool ascii);
 349 extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 350                         const void *buf, size_t len);
 351
 352 extern const char hex_asc[];
 353 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 354 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 355
 356 static inline char *pack_hex_byte(char *buf, u8 byte)
 357 {
 358         *buf++ = hex_asc_hi(byte);
 359         *buf++ = hex_asc_lo(byte);
 360         return buf;
 361 }
 362
 363 #ifndef pr_fmt
 364 #define pr_fmt(fmt) fmt
 365 #endif
 366
 367 #define pr_emerg(fmt, ...) \
 368         printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
 369 #define pr_alert(fmt, ...) \
 370         printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
 371 #define pr_crit(fmt, ...) \
 372         printk(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
 373 #define pr_err(fmt, ...) \
 374         printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
 375 #define pr_warning(fmt, ...) \
 376         printk(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
 377 #define pr_notice(fmt, ...) \
 378         printk(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
 379 #define pr_info(fmt, ...) \
 380         printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
 381 #define pr_cont(fmt, ...) \
 382         printk(KERN_CONT fmt, ##__VA_ARGS__)
 383
 384 /* pr_devel() should produce zero code unless DEBUG is defined */
 385 #ifdef DEBUG
 386 #define pr_devel(fmt, ...) \
 387         printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 388 #else
 389 #define pr_devel(fmt, ...) \
 390         ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; })
 391 #endif
 392
 393 /* If you are writing a driver, please use dev_dbg instead */
 394 #if defined(DEBUG)
 395 #define pr_debug(fmt, ...) \
 396         printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 397 #elif defined(CONFIG_DYNAMIC_DEBUG)
 398 /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
 399 #define pr_debug(fmt, ...) do { \
 400         dynamic_pr_debug(fmt, ##__VA_ARGS__); \
 401         } while (0)
 402 #else
 403 #define pr_debug(fmt, ...) \
 404         ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; })
 405 #endif
 406
 407 /*
 408  * General tracing related utility functions - trace_printk(),
 409  * tracing_on/tracing_off and tracing_start()/tracing_stop
 410  *
 411  * Use tracing_on/tracing_off when you want to quickly turn on or off
 412  * tracing. It simply enables or disables the recording of the trace events.
 413  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 414  * file, which gives a means for the kernel and userspace to interact.
 415  * Place a tracing_off() in the kernel where you want tracing to end.
 416  * From user space, examine the trace, and then echo 1 > tracing_on
 417  * to continue tracing.
 418  *
 419  * tracing_stop/tracing_start has slightly more overhead. It is used
 420  * by things like suspend to ram where disabling the recording of the
 421  * trace is not enough, but tracing must actually stop because things
 422  * like calling smp_processor_id() may crash the system.
 423  *
 424  * Most likely, you want to use tracing_on/tracing_off.
 425  */
 426 #ifdef CONFIG_RING_BUFFER
 427 void tracing_on(void);
 428 void tracing_off(void);
 429 /* trace_off_permanent stops recording with no way to bring it back */
 430 void tracing_off_permanent(void);
 431 int tracing_is_on(void);
 432 #else
 433 static inline void tracing_on(void) { }
 434 static inline void tracing_off(void) { }
 435 static inline void tracing_off_permanent(void) { }
 436 static inline int tracing_is_on(void) { return 0; }
 437 #endif
 438 #ifdef CONFIG_TRACING
 439 extern void tracing_start(void);
 440 extern void tracing_stop(void);
 441 extern void ftrace_off_permanent(void);
 442
 443 extern void
 444 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 445
 446 static inline void __attribute__ ((format (printf, 1, 2)))
 447 ____trace_printk_check_format(const char *fmt, ...)
 448 {
 449 }
 450 #define __trace_printk_check_format(fmt, args...)                       \
 451 do {                                                                    \
 452         if (0)                                                          \
 453                 ____trace_printk_check_format(fmt, ##args);             \
 454 } while (0)
 455
 456 /**
 457  * trace_printk - printf formatting in the ftrace buffer
 458  * @fmt: the printf format for printing
 459  *
 460  * Note: __trace_printk is an internal function for trace_printk and
 461  *       the @ip is passed in via the trace_printk macro.
 462  *
 463  * This function allows a kernel developer to debug fast path sections
 464  * that printk is not appropriate for. By scattering in various
 465  * printk like tracing in the code, a developer can quickly see
 466  * where problems are occurring.
 467  *
 468  * This is intended as a debugging tool for the developer only.
 469  * Please refrain from leaving trace_printks scattered around in
 470  * your code.
 471  */
 472
 473 #define trace_printk(fmt, args...)                                      \
 474 do {                                                                    \
 475         __trace_printk_check_format(fmt, ##args);                       \
 476         if (__builtin_constant_p(fmt)) {                                \
 477                 static const char *trace_printk_fmt                     \
 478                   __attribute__((section("__trace_printk_fmt"))) =      \
 479                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 480                                                                         \
 481                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 482         } else                                                          \
 483                 __trace_printk(_THIS_IP_, fmt, ##args);         \
 484 } while (0)
 485
 486 extern int
 487 __trace_bprintk(unsigned long ip, const char *fmt, ...)
 488         __attribute__ ((format (printf, 2, 3)));
 489
 490 extern int
 491 __trace_printk(unsigned long ip, const char *fmt, ...)
 492         __attribute__ ((format (printf, 2, 3)));
 493
 494 /*
 495  * The double __builtin_constant_p is because gcc will give us an error
 496  * if we try to allocate the static variable to fmt if it is not a
 497  * constant. Even with the outer if statement.
 498  */
 499 #define ftrace_vprintk(fmt, vargs)                                      \
 500 do {                                                                    \
 501         if (__builtin_constant_p(fmt)) {                                \
 502                 static const char *trace_printk_fmt                     \
 503                   __attribute__((section("__trace_printk_fmt"))) =      \
 504                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 505                                                                         \
 506                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 507         } else                                                          \
 508                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 509 } while (0)
 510
 511 extern int
 512 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 513
 514 extern int
 515 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 516
 517 extern void ftrace_dump(void);
 518 #else
 519 static inline void
 520 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 521 static inline int
 522 trace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
 523
 524 static inline void tracing_start(void) { }
 525 static inline void tracing_stop(void) { }
 526 static inline void ftrace_off_permanent(void) { }
 527 static inline int
 528 trace_printk(const char *fmt, ...)
 529 {
 530         return 0;
 531 }
 532 static inline int
 533 ftrace_vprintk(const char *fmt, va_list ap)
 534 {
 535         return 0;
 536 }
 537 static inline void ftrace_dump(void) { }
 538 #endif /* CONFIG_TRACING */
 539
 540 /*
 541  *      Display an IP address in readable format.
 542  */
 543
 544 #define NIPQUAD(addr) \
 545         ((unsigned char *)&addr)[0], \
 546         ((unsigned char *)&addr)[1], \
 547         ((unsigned char *)&addr)[2], \
 548         ((unsigned char *)&addr)[3]
 549 #define NIPQUAD_FMT "%u.%u.%u.%u"
 550
 551 /*
 552  * min()/max()/clamp() macros that also do
 553  * strict type-checking.. See the
 554  * "unnecessary" pointer comparison.
 555  */
 556 #define min(x, y) ({                            \
 557         typeof(x) _min1 = (x);                  \
 558         typeof(y) _min2 = (y);                  \
 559         (void) (&_min1 == &_min2);              \
 560         _min1 < _min2 ? _min1 : _min2; })
 561
 562 #define max(x, y) ({                            \
 563         typeof(x) _max1 = (x);                  \
 564         typeof(y) _max2 = (y);                  \
 565         (void) (&_max1 == &_max2);              \
 566         _max1 > _max2 ? _max1 : _max2; })
 567
 568 /**
 569  * clamp - return a value clamped to a given range with strict typechecking
 570  * @val: current value
 571  * @min: minimum allowable value
 572  * @max: maximum allowable value
 573  *
 574  * This macro does strict typechecking of min/max to make sure they are of the
 575  * same type as val.  See the unnecessary pointer comparisons.
 576  */
 577 #define clamp(val, min, max) ({                 \
 578         typeof(val) __val = (val);              \
 579         typeof(min) __min = (min);              \
 580         typeof(max) __max = (max);              \
 581         (void) (&__val == &__min);              \
 582         (void) (&__val == &__max);              \
 583         __val = __val < __min ? __min: __val;   \
 584         __val > __max ? __max: __val; })
 585
 586 /*
 587  * ..and if you can't take the strict
 588  * types, you can specify one yourself.
 589  *
 590  * Or not use min/max/clamp at all, of course.
 591  */
 592 #define min_t(type, x, y) ({                    \
 593         type __min1 = (x);                      \
 594         type __min2 = (y);                      \
 595         __min1 < __min2 ? __min1: __min2; })
 596
 597 #define max_t(type, x, y) ({                    \
 598         type __max1 = (x);                      \
 599         type __max2 = (y);                      \
 600         __max1 > __max2 ? __max1: __max2; })
 601
 602 /**
 603  * clamp_t - return a value clamped to a given range using a given type
 604  * @type: the type of variable to use
 605  * @val: current value
 606  * @min: minimum allowable value
 607  * @max: maximum allowable value
 608  *
 609  * This macro does no typechecking and uses temporary variables of type
 610  * 'type' to make all the comparisons.
 611  */
 612 #define clamp_t(type, val, min, max) ({         \
 613         type __val = (val);                     \
 614         type __min = (min);                     \
 615         type __max = (max);                     \
 616         __val = __val < __min ? __min: __val;   \
 617         __val > __max ? __max: __val; })
 618
 619 /**
 620  * clamp_val - return a value clamped to a given range using val's type
 621  * @val: current value
 622  * @min: minimum allowable value
 623  * @max: maximum allowable value
 624  *
 625  * This macro does no typechecking and uses temporary variables of whatever
 626  * type the input argument 'val' is.  This is useful when val is an unsigned
 627  * type and min and max are literals that will otherwise be assigned a signed
 628  * integer type.
 629  */
 630 #define clamp_val(val, min, max) ({             \
 631         typeof(val) __val = (val);              \
 632         typeof(val) __min = (min);              \
 633         typeof(val) __max = (max);              \
 634         __val = __val < __min ? __min: __val;   \
 635         __val > __max ? __max: __val; })
 636
 637
 638 /*
 639  * swap - swap value of @a and @b
 640  */
 641 #define swap(a, b) \
 642         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 643
 644 /**
 645  * container_of - cast a member of a structure out to the containing structure
 646  * @ptr:        the pointer to the member.
 647  * @type:       the type of the container struct this is embedded in.
 648  * @member:     the name of the member within the struct.
 649  *
 650  */
 651 #define container_of(ptr, type, member) ({                      \
 652         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 653         (type *)( (char *)__mptr - offsetof(type,member) );})
 654
 655 struct sysinfo;
 656 extern int do_sysinfo(struct sysinfo *info);
 657
 658 #endif /* __KERNEL__ */
 659
 660 #define SI_LOAD_SHIFT   16
 661 struct sysinfo {
 662         long uptime;                    /* Seconds since boot */
 663         unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 664         unsigned long totalram;         /* Total usable main memory size */
 665         unsigned long freeram;          /* Available memory size */
 666         unsigned long sharedram;        /* Amount of shared memory */
 667         unsigned long bufferram;        /* Memory used by buffers */
 668         unsigned long totalswap;        /* Total swap space size */
 669         unsigned long freeswap;         /* swap space still available */
 670         unsigned short procs;           /* Number of current processes */
 671         unsigned short pad;             /* explicit padding for m68k */
 672         unsigned long totalhigh;        /* Total high memory size */
 673         unsigned long freehigh;         /* Available high memory size */
 674         unsigned int mem_unit;          /* Memory unit size in bytes */
 675         char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 676 };
 677
 678 /* Force a compilation error if condition is true */
 679 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 680
 681 /* Force a compilation error if condition is true, but also produce a
 682    result (of value 0 and type size_t), so the expression can be used
 683    e.g. in a structure initializer (or where-ever else comma expressions
 684    aren't permitted). */
 685 #define BUILD_BUG_ON_ZERO(e) (sizeof(char[1 - 2 * !!(e)]) - 1)
 686
 687 /* Trap pasters of __FUNCTION__ at compile-time */
 688 #define __FUNCTION__ (__func__)
 689
 690 /* This helps us to avoid #ifdef CONFIG_NUMA */
 691 #ifdef CONFIG_NUMA
 692 #define NUMA_BUILD 1
 693 #else
 694 #define NUMA_BUILD 0
 695 #endif
 696
 697 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 698 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 699 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 700 #endif
 701
 702 #endif