include/linux/kernel.h

   1 #ifndef _LINUX_KERNEL_H
   2 #define _LINUX_KERNEL_H
   3
   4
   5 #include <stdarg.h>
   6 #include <linux/linkage.h>
   7 #include <linux/stddef.h>
   8 #include <linux/types.h>
   9 #include <linux/compiler.h>
  10 #include <linux/bitops.h>
  11 #include <linux/log2.h>
  12 #include <linux/typecheck.h>
  13 #include <linux/printk.h>
  14 #include <linux/dynamic_debug.h>
  15 #include <asm/byteorder.h>
  16 #include <uapi/linux/kernel.h>
  17
  18 #define USHRT_MAX       ((u16)(~0U))
  19 #define SHRT_MAX        ((s16)(USHRT_MAX>>1))
  20 #define SHRT_MIN        ((s16)(-SHRT_MAX - 1))
  21 #define INT_MAX         ((int)(~0U>>1))
  22 #define INT_MIN         (-INT_MAX - 1)
  23 #define UINT_MAX        (~0U)
  24 #define LONG_MAX        ((long)(~0UL>>1))
  25 #define LONG_MIN        (-LONG_MAX - 1)
  26 #define ULONG_MAX       (~0UL)
  27 #define LLONG_MAX       ((long long)(~0ULL>>1))
  28 #define LLONG_MIN       (-LLONG_MAX - 1)
  29 #define ULLONG_MAX      (~0ULL)
  30 #define SIZE_MAX        (~(size_t)0)
  31
  32 #define STACK_MAGIC     0xdeadbeef
  33
  34 #define REPEAT_BYTE(x)  ((~0ul / 0xff) * (x))
  35
  36 #define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
  37 #define __ALIGN_MASK(x, mask)   __ALIGN_KERNEL_MASK((x), (mask))
  38 #define PTR_ALIGN(p, a)         ((typeof(p))ALIGN((unsigned long)(p), (a)))
  39 #define IS_ALIGNED(x, a)                (((x) & ((typeof(x))(a) - 1)) == 0)
  40
  41 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  42
  43 /*
  44  * This looks more complex than it should be. But we need to
  45  * get the type for the ~ right in round_down (it needs to be
  46  * as wide as the result!), and we want to evaluate the macro
  47  * arguments just once each.
  48  */
  49 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
  50 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
  51 #define round_down(x, y) ((x) & ~__round_mask(x, y))
  52
  53 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  54 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  55 #define DIV_ROUND_UP_ULL(ll,d) \
  56         ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
  57
  58 #if BITS_PER_LONG == 32
  59 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
  60 #else
  61 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
  62 #endif
  63
  64 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
  65 #define roundup(x, y) (                                 \
  66 {                                                       \
  67         const typeof(y) __y = y;                        \
  68         (((x) + (__y - 1)) / __y) * __y;                \
  69 }                                                       \
  70 )
  71 #define rounddown(x, y) (                               \
  72 {                                                       \
  73         typeof(x) __x = (x);                            \
  74         __x - (__x % (y));                              \
  75 }                                                       \
  76 )
  77
  78 /*
  79  * Divide positive or negative dividend by positive divisor and round
  80  * to closest integer. Result is undefined for negative divisors and
  81  * for negative dividends if the divisor variable type is unsigned.
  82  */
  83 #define DIV_ROUND_CLOSEST(x, divisor)(                  \
  84 {                                                       \
  85         typeof(x) __x = x;                              \
  86         typeof(divisor) __d = divisor;                  \
  87         (((typeof(x))-1) > 0 ||                         \
  88          ((typeof(divisor))-1) > 0 || (__x) > 0) ?      \
  89                 (((__x) + ((__d) / 2)) / (__d)) :       \
  90                 (((__x) - ((__d) / 2)) / (__d));        \
  91 }                                                       \
  92 )
  93
  94 /*
  95  * Multiplies an integer by a fraction, while avoiding unnecessary
  96  * overflow or loss of precision.
  97  */
  98 #define mult_frac(x, numer, denom)(                     \
  99 {                                                       \
 100         typeof(x) quot = (x) / (denom);                 \
 101         typeof(x) rem  = (x) % (denom);                 \
 102         (quot * (numer)) + ((rem * (numer)) / (denom)); \
 103 }                                                       \
 104 )
 105
 106
 107 #define _RET_IP_                (unsigned long)__builtin_return_address(0)
 108 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
 109
 110 #ifdef CONFIG_LBDAF
 111 # include <asm/div64.h>
 112 # define sector_div(a, b) do_div(a, b)
 113 #else
 114 # define sector_div(n, b)( \
 115 { \
 116         int _res; \
 117         _res = (n) % (b); \
 118         (n) /= (b); \
 119         _res; \
 120 } \
 121 )
 122 #endif
 123
 124 /**
 125  * upper_32_bits - return bits 32-63 of a number
 126  * @n: the number we're accessing
 127  *
 128  * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
 129  * the "right shift count >= width of type" warning when that quantity is
 130  * 32-bits.
 131  */
 132 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
 133
 134 /**
 135  * lower_32_bits - return bits 0-31 of a number
 136  * @n: the number we're accessing
 137  */
 138 #define lower_32_bits(n) ((u32)(n))
 139
 140 struct completion;
 141 struct pt_regs;
 142 struct user;
 143
 144 #ifdef CONFIG_PREEMPT_VOLUNTARY
 145 extern int _cond_resched(void);
 146 # define might_resched() _cond_resched()
 147 #else
 148 # define might_resched() do { } while (0)
 149 #endif
 150
 151 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 152   void __might_sleep(const char *file, int line, int preempt_offset);
 153 /**
 154  * might_sleep - annotation for functions that can sleep
 155  *
 156  * this macro will print a stack trace if it is executed in an atomic
 157  * context (spinlock, irq-handler, ...).
 158  *
 159  * This is a useful debugging help to be able to catch problems early and not
 160  * be bitten later when the calling function happens to sleep when it is not
 161  * supposed to.
 162  */
 163 # define might_sleep() \
 164         do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 165 #else
 166   static inline void __might_sleep(const char *file, int line,
 167                                    int preempt_offset) { }
 168 # define might_sleep() do { might_resched(); } while (0)
 169 #endif
 170
 171 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 172
 173 /*
 174  * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
 175  * input types abs() returns a signed long.
 176  * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
 177  * for those.
 178  */
 179 #define abs(x) ({                                               \
 180                 long ret;                                       \
 181                 if (sizeof(x) == sizeof(long)) {                \
 182                         long __x = (x);                         \
 183                         ret = (__x < 0) ? -__x : __x;           \
 184                 } else {                                        \
 185                         int __x = (x);                          \
 186                         ret = (__x < 0) ? -__x : __x;           \
 187                 }                                               \
 188                 ret;                                            \
 189         })
 190
 191 #define abs64(x) ({                             \
 192                 s64 __x = (x);                  \
 193                 (__x < 0) ? -__x : __x;         \
 194         })
 195
 196 #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)
 197 void might_fault(void);
 198 #else
 199 static inline void might_fault(void) { }
 200 #endif
 201
 202 extern struct atomic_notifier_head panic_notifier_list;
 203 extern long (*panic_blink)(int state);
 204 __printf(1, 2)
 205 void panic(const char *fmt, ...)
 206         __noreturn __cold;
 207 extern void oops_enter(void);
 208 extern void oops_exit(void);
 209 void print_oops_end_marker(void);
 210 extern int oops_may_print(void);
 211 void do_exit(long error_code)
 212         __noreturn;
 213 void complete_and_exit(struct completion *, long)
 214         __noreturn;
 215
 216 /* Internal, do not use. */
 217 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 218 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 219
 220 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 221 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 222
 223 /**
 224  * kstrtoul - convert a string to an unsigned long
 225  * @s: The start of the string. The string must be null-terminated, and may also
 226  *  include a single newline before its terminating null. The first character
 227  *  may also be a plus sign, but not a minus sign.
 228  * @base: The number base to use. The maximum supported base is 16. If base is
 229  *  given as 0, then the base of the string is automatically detected with the
 230  *  conventional semantics - If it begins with 0x the number will be parsed as a
 231  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 232  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 233  * @res: Where to write the result of the conversion on success.
 234  *
 235  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 236  * Used as a replacement for the obsolete simple_strtoull. Return code must
 237  * be checked.
 238 */
 239 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 240 {
 241         /*
 242          * We want to shortcut function call, but
 243          * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 244          */
 245         if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 246             __alignof__(unsigned long) == __alignof__(unsigned long long))
 247                 return kstrtoull(s, base, (unsigned long long *)res);
 248         else
 249                 return _kstrtoul(s, base, res);
 250 }
 251
 252 /**
 253  * kstrtol - convert a string to a long
 254  * @s: The start of the string. The string must be null-terminated, and may also
 255  *  include a single newline before its terminating null. The first character
 256  *  may also be a plus sign or a minus sign.
 257  * @base: The number base to use. The maximum supported base is 16. If base is
 258  *  given as 0, then the base of the string is automatically detected with the
 259  *  conventional semantics - If it begins with 0x the number will be parsed as a
 260  *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 261  *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 262  * @res: Where to write the result of the conversion on success.
 263  *
 264  * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 265  * Used as a replacement for the obsolete simple_strtoull. Return code must
 266  * be checked.
 267  */
 268 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 269 {
 270         /*
 271          * We want to shortcut function call, but
 272          * __builtin_types_compatible_p(long, long long) = 0.
 273          */
 274         if (sizeof(long) == sizeof(long long) &&
 275             __alignof__(long) == __alignof__(long long))
 276                 return kstrtoll(s, base, (long long *)res);
 277         else
 278                 return _kstrtol(s, base, res);
 279 }
 280
 281 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 282 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 283
 284 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 285 {
 286         return kstrtoull(s, base, res);
 287 }
 288
 289 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 290 {
 291         return kstrtoll(s, base, res);
 292 }
 293
 294 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 295 {
 296         return kstrtouint(s, base, res);
 297 }
 298
 299 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 300 {
 301         return kstrtoint(s, base, res);
 302 }
 303
 304 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 305 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 306 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 307 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 308
 309 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 310 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 311 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 312 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 313 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 314 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 315 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 316 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 317 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 318 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 319
 320 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 321 {
 322         return kstrtoull_from_user(s, count, base, res);
 323 }
 324
 325 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 326 {
 327         return kstrtoll_from_user(s, count, base, res);
 328 }
 329
 330 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 331 {
 332         return kstrtouint_from_user(s, count, base, res);
 333 }
 334
 335 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 336 {
 337         return kstrtoint_from_user(s, count, base, res);
 338 }
 339
 340 /* Obsolete, do not use.  Use kstrto<foo> instead */
 341
 342 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 343 extern long simple_strtol(const char *,char **,unsigned int);
 344 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 345 extern long long simple_strtoll(const char *,char **,unsigned int);
 346 #define strict_strtoul  kstrtoul
 347 #define strict_strtol   kstrtol
 348 #define strict_strtoull kstrtoull
 349 #define strict_strtoll  kstrtoll
 350
 351 extern int num_to_str(char *buf, int size, unsigned long long num);
 352
 353 /* lib/printf utilities */
 354
 355 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 356 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 357 extern __printf(3, 4)
 358 int snprintf(char *buf, size_t size, const char *fmt, ...);
 359 extern __printf(3, 0)
 360 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 361 extern __printf(3, 4)
 362 int scnprintf(char *buf, size_t size, const char *fmt, ...);
 363 extern __printf(3, 0)
 364 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 365 extern __printf(2, 3)
 366 char *kasprintf(gfp_t gfp, const char *fmt, ...);
 367 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 368
 369 extern __scanf(2, 3)
 370 int sscanf(const char *, const char *, ...);
 371 extern __scanf(2, 0)
 372 int vsscanf(const char *, const char *, va_list);
 373
 374 extern int get_option(char **str, int *pint);
 375 extern char *get_options(const char *str, int nints, int *ints);
 376 extern unsigned long long memparse(const char *ptr, char **retptr);
 377
 378 extern int core_kernel_text(unsigned long addr);
 379 extern int core_kernel_data(unsigned long addr);
 380 extern int __kernel_text_address(unsigned long addr);
 381 extern int kernel_text_address(unsigned long addr);
 382 extern int func_ptr_is_kernel_text(void *ptr);
 383
 384 struct pid;
 385 extern struct pid *session_of_pgrp(struct pid *pgrp);
 386
 387 unsigned long int_sqrt(unsigned long);
 388
 389 extern void bust_spinlocks(int yes);
 390 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 391 extern int panic_timeout;
 392 extern int panic_on_oops;
 393 extern int panic_on_unrecovered_nmi;
 394 extern int panic_on_io_nmi;
 395 extern int sysctl_panic_on_stackoverflow;
 396 extern const char *print_tainted(void);
 397 enum lockdep_ok {
 398         LOCKDEP_STILL_OK,
 399         LOCKDEP_NOW_UNRELIABLE
 400 };
 401 extern void add_taint(unsigned flag, enum lockdep_ok);
 402 extern int test_taint(unsigned flag);
 403 extern unsigned long get_taint(void);
 404 extern int root_mountflags;
 405
 406 extern bool early_boot_irqs_disabled;
 407
 408 /* Values used for system_state */
 409 extern enum system_states {
 410         SYSTEM_BOOTING,
 411         SYSTEM_RUNNING,
 412         SYSTEM_HALT,
 413         SYSTEM_POWER_OFF,
 414         SYSTEM_RESTART,
 415 } system_state;
 416
 417 #define TAINT_PROPRIETARY_MODULE        0
 418 #define TAINT_FORCED_MODULE             1
 419 #define TAINT_UNSAFE_SMP                2
 420 #define TAINT_FORCED_RMMOD              3
 421 #define TAINT_MACHINE_CHECK             4
 422 #define TAINT_BAD_PAGE                  5
 423 #define TAINT_USER                      6
 424 #define TAINT_DIE                       7
 425 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
 426 #define TAINT_WARN                      9
 427 #define TAINT_CRAP                      10
 428 #define TAINT_FIRMWARE_WORKAROUND       11
 429 #define TAINT_OOT_MODULE                12
 430
 431 extern const char hex_asc[];
 432 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 433 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 434
 435 static inline char *hex_byte_pack(char *buf, u8 byte)
 436 {
 437         *buf++ = hex_asc_hi(byte);
 438         *buf++ = hex_asc_lo(byte);
 439         return buf;
 440 }
 441
 442 static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 443 {
 444         return hex_byte_pack(buf, byte);
 445 }
 446
 447 extern int hex_to_bin(char ch);
 448 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 449
 450 int mac_pton(const char *s, u8 *mac);
 451
 452 /*
 453  * General tracing related utility functions - trace_printk(),
 454  * tracing_on/tracing_off and tracing_start()/tracing_stop
 455  *
 456  * Use tracing_on/tracing_off when you want to quickly turn on or off
 457  * tracing. It simply enables or disables the recording of the trace events.
 458  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 459  * file, which gives a means for the kernel and userspace to interact.
 460  * Place a tracing_off() in the kernel where you want tracing to end.
 461  * From user space, examine the trace, and then echo 1 > tracing_on
 462  * to continue tracing.
 463  *
 464  * tracing_stop/tracing_start has slightly more overhead. It is used
 465  * by things like suspend to ram where disabling the recording of the
 466  * trace is not enough, but tracing must actually stop because things
 467  * like calling smp_processor_id() may crash the system.
 468  *
 469  * Most likely, you want to use tracing_on/tracing_off.
 470  */
 471 #ifdef CONFIG_RING_BUFFER
 472 /* trace_off_permanent stops recording with no way to bring it back */
 473 void tracing_off_permanent(void);
 474 #else
 475 static inline void tracing_off_permanent(void) { }
 476 #endif
 477
 478 enum ftrace_dump_mode {
 479         DUMP_NONE,
 480         DUMP_ALL,
 481         DUMP_ORIG,
 482 };
 483
 484 #ifdef CONFIG_TRACING
 485 void tracing_on(void);
 486 void tracing_off(void);
 487 int tracing_is_on(void);
 488 void tracing_snapshot(void);
 489 void tracing_snapshot_alloc(void);
 490
 491 extern void tracing_start(void);
 492 extern void tracing_stop(void);
 493 extern void ftrace_off_permanent(void);
 494
 495 static inline __printf(1, 2)
 496 void ____trace_printk_check_format(const char *fmt, ...)
 497 {
 498 }
 499 #define __trace_printk_check_format(fmt, args...)                       \
 500 do {                                                                    \
 501         if (0)                                                          \
 502                 ____trace_printk_check_format(fmt, ##args);             \
 503 } while (0)
 504
 505 /**
 506  * trace_printk - printf formatting in the ftrace buffer
 507  * @fmt: the printf format for printing
 508  *
 509  * Note: __trace_printk is an internal function for trace_printk and
 510  *       the @ip is passed in via the trace_printk macro.
 511  *
 512  * This function allows a kernel developer to debug fast path sections
 513  * that printk is not appropriate for. By scattering in various
 514  * printk like tracing in the code, a developer can quickly see
 515  * where problems are occurring.
 516  *
 517  * This is intended as a debugging tool for the developer only.
 518  * Please refrain from leaving trace_printks scattered around in
 519  * your code. (Extra memory is used for special buffers that are
 520  * allocated when trace_printk() is used)
 521  *
 522  * A little optization trick is done here. If there's only one
 523  * argument, there's no need to scan the string for printf formats.
 524  * The trace_puts() will suffice. But how can we take advantage of
 525  * using trace_puts() when trace_printk() has only one argument?
 526  * By stringifying the args and checking the size we can tell
 527  * whether or not there are args. __stringify((__VA_ARGS__)) will
 528  * turn into "()\0" with a size of 3 when there are no args, anything
 529  * else will be bigger. All we need to do is define a string to this,
 530  * and then take its size and compare to 3. If it's bigger, use
 531  * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
 532  * let gcc optimize the rest.
 533  */
 534
 535 #define trace_printk(fmt, ...)                          \
 536 do {                                                    \
 537         char _______STR[] = __stringify((__VA_ARGS__)); \
 538         if (sizeof(_______STR) > 3)                     \
 539                 do_trace_printk(fmt, ##__VA_ARGS__);    \
 540         else                                            \
 541                 trace_puts(fmt);                        \
 542 } while (0)
 543
 544 #define do_trace_printk(fmt, args...)                                   \
 545 do {                                                                    \
 546         static const char *trace_printk_fmt                             \
 547                 __attribute__((section("__trace_printk_fmt"))) =        \
 548                 __builtin_constant_p(fmt) ? fmt : NULL;                 \
 549                                                                         \
 550         __trace_printk_check_format(fmt, ##args);                       \
 551                                                                         \
 552         if (__builtin_constant_p(fmt))                                  \
 553                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 554         else                                                            \
 555                 __trace_printk(_THIS_IP_, fmt, ##args);                 \
 556 } while (0)
 557
 558 extern __printf(2, 3)
 559 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 560
 561 extern __printf(2, 3)
 562 int __trace_printk(unsigned long ip, const char *fmt, ...);
 563
 564 /**
 565  * trace_puts - write a string into the ftrace buffer
 566  * @str: the string to record
 567  *
 568  * Note: __trace_bputs is an internal function for trace_puts and
 569  *       the @ip is passed in via the trace_puts macro.
 570  *
 571  * This is similar to trace_printk() but is made for those really fast
 572  * paths that a developer wants the least amount of "Heisenbug" affects,
 573  * where the processing of the print format is still too much.
 574  *
 575  * This function allows a kernel developer to debug fast path sections
 576  * that printk is not appropriate for. By scattering in various
 577  * printk like tracing in the code, a developer can quickly see
 578  * where problems are occurring.
 579  *
 580  * This is intended as a debugging tool for the developer only.
 581  * Please refrain from leaving trace_puts scattered around in
 582  * your code. (Extra memory is used for special buffers that are
 583  * allocated when trace_puts() is used)
 584  *
 585  * Returns: 0 if nothing was written, positive # if string was.
 586  *  (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
 587  */
 588
 589 #define trace_puts(str) ({                                              \
 590         static const char *trace_printk_fmt                             \
 591                 __attribute__((section("__trace_printk_fmt"))) =        \
 592                 __builtin_constant_p(str) ? str : NULL;                 \
 593                                                                         \
 594         if (__builtin_constant_p(str))                                  \
 595                 __trace_bputs(_THIS_IP_, trace_printk_fmt);             \
 596         else                                                            \
 597                 __trace_puts(_THIS_IP_, str, strlen(str));              \
 598 })
 599 extern int __trace_bputs(unsigned long ip, const char *str);
 600 extern int __trace_puts(unsigned long ip, const char *str, int size);
 601
 602 extern void trace_dump_stack(int skip);
 603
 604 /*
 605  * The double __builtin_constant_p is because gcc will give us an error
 606  * if we try to allocate the static variable to fmt if it is not a
 607  * constant. Even with the outer if statement.
 608  */
 609 #define ftrace_vprintk(fmt, vargs)                                      \
 610 do {                                                                    \
 611         if (__builtin_constant_p(fmt)) {                                \
 612                 static const char *trace_printk_fmt                     \
 613                   __attribute__((section("__trace_printk_fmt"))) =      \
 614                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 615                                                                         \
 616                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 617         } else                                                          \
 618                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 619 } while (0)
 620
 621 extern int
 622 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 623
 624 extern int
 625 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 626
 627 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 628 #else
 629 static inline void tracing_start(void) { }
 630 static inline void tracing_stop(void) { }
 631 static inline void ftrace_off_permanent(void) { }
 632 static inline void trace_dump_stack(void) { }
 633
 634 static inline void tracing_on(void) { }
 635 static inline void tracing_off(void) { }
 636 static inline int tracing_is_on(void) { return 0; }
 637 static inline void tracing_snapshot(void) { }
 638 static inline void tracing_snapshot_alloc(void) { }
 639
 640 static inline __printf(1, 2)
 641 int trace_printk(const char *fmt, ...)
 642 {
 643         return 0;
 644 }
 645 static inline int
 646 ftrace_vprintk(const char *fmt, va_list ap)
 647 {
 648         return 0;
 649 }
 650 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 651 #endif /* CONFIG_TRACING */
 652
 653 /*
 654  * min()/max()/clamp() macros that also do
 655  * strict type-checking.. See the
 656  * "unnecessary" pointer comparison.
 657  */
 658 #define min(x, y) ({                            \
 659         typeof(x) _min1 = (x);                  \
 660         typeof(y) _min2 = (y);                  \
 661         (void) (&_min1 == &_min2);              \
 662         _min1 < _min2 ? _min1 : _min2; })
 663
 664 #define max(x, y) ({                            \
 665         typeof(x) _max1 = (x);                  \
 666         typeof(y) _max2 = (y);                  \
 667         (void) (&_max1 == &_max2);              \
 668         _max1 > _max2 ? _max1 : _max2; })
 669
 670 #define min3(x, y, z) ({                        \
 671         typeof(x) _min1 = (x);                  \
 672         typeof(y) _min2 = (y);                  \
 673         typeof(z) _min3 = (z);                  \
 674         (void) (&_min1 == &_min2);              \
 675         (void) (&_min1 == &_min3);              \
 676         _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 677                 (_min2 < _min3 ? _min2 : _min3); })
 678
 679 #define max3(x, y, z) ({                        \
 680         typeof(x) _max1 = (x);                  \
 681         typeof(y) _max2 = (y);                  \
 682         typeof(z) _max3 = (z);                  \
 683         (void) (&_max1 == &_max2);              \
 684         (void) (&_max1 == &_max3);              \
 685         _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 686                 (_max2 > _max3 ? _max2 : _max3); })
 687
 688 /**
 689  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 690  * @x: value1
 691  * @y: value2
 692  */
 693 #define min_not_zero(x, y) ({                   \
 694         typeof(x) __x = (x);                    \
 695         typeof(y) __y = (y);                    \
 696         __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 697
 698 /**
 699  * clamp - return a value clamped to a given range with strict typechecking
 700  * @val: current value
 701  * @min: minimum allowable value
 702  * @max: maximum allowable value
 703  *
 704  * This macro does strict typechecking of min/max to make sure they are of the
 705  * same type as val.  See the unnecessary pointer comparisons.
 706  */
 707 #define clamp(val, min, max) ({                 \
 708         typeof(val) __val = (val);              \
 709         typeof(min) __min = (min);              \
 710         typeof(max) __max = (max);              \
 711         (void) (&__val == &__min);              \
 712         (void) (&__val == &__max);              \
 713         __val = __val < __min ? __min: __val;   \
 714         __val > __max ? __max: __val; })
 715
 716 /*
 717  * ..and if you can't take the strict
 718  * types, you can specify one yourself.
 719  *
 720  * Or not use min/max/clamp at all, of course.
 721  */
 722 #define min_t(type, x, y) ({                    \
 723         type __min1 = (x);                      \
 724         type __min2 = (y);                      \
 725         __min1 < __min2 ? __min1: __min2; })
 726
 727 #define max_t(type, x, y) ({                    \
 728         type __max1 = (x);                      \
 729         type __max2 = (y);                      \
 730         __max1 > __max2 ? __max1: __max2; })
 731
 732 /**
 733  * clamp_t - return a value clamped to a given range using a given type
 734  * @type: the type of variable to use
 735  * @val: current value
 736  * @min: minimum allowable value
 737  * @max: maximum allowable value
 738  *
 739  * This macro does no typechecking and uses temporary variables of type
 740  * 'type' to make all the comparisons.
 741  */
 742 #define clamp_t(type, val, min, max) ({         \
 743         type __val = (val);                     \
 744         type __min = (min);                     \
 745         type __max = (max);                     \
 746         __val = __val < __min ? __min: __val;   \
 747         __val > __max ? __max: __val; })
 748
 749 /**
 750  * clamp_val - return a value clamped to a given range using val's type
 751  * @val: current value
 752  * @min: minimum allowable value
 753  * @max: maximum allowable value
 754  *
 755  * This macro does no typechecking and uses temporary variables of whatever
 756  * type the input argument 'val' is.  This is useful when val is an unsigned
 757  * type and min and max are literals that will otherwise be assigned a signed
 758  * integer type.
 759  */
 760 #define clamp_val(val, min, max) ({             \
 761         typeof(val) __val = (val);              \
 762         typeof(val) __min = (min);              \
 763         typeof(val) __max = (max);              \
 764         __val = __val < __min ? __min: __val;   \
 765         __val > __max ? __max: __val; })
 766
 767
 768 /*
 769  * swap - swap value of @a and @b
 770  */
 771 #define swap(a, b) \
 772         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 773
 774 /**
 775  * container_of - cast a member of a structure out to the containing structure
 776  * @ptr:        the pointer to the member.
 777  * @type:       the type of the container struct this is embedded in.
 778  * @member:     the name of the member within the struct.
 779  *
 780  */
 781 #define container_of(ptr, type, member) ({                      \
 782         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 783         (type *)( (char *)__mptr - offsetof(type,member) );})
 784
 785 /* Trap pasters of __FUNCTION__ at compile-time */
 786 #define __FUNCTION__ (__func__)
 787
 788 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 789 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 790 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 791 #endif
 792
 793 #endif