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 #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
   8 #define __ALIGN_KERNEL_MASK(x, mask)    (((x) + (mask)) & ~(mask))
   9
  10 #ifdef __KERNEL__
  11
  12 #include <stdarg.h>
  13 #include <linux/linkage.h>
  14 #include <linux/stddef.h>
  15 #include <linux/types.h>
  16 #include <linux/compiler.h>
  17 #include <linux/bitops.h>
  18 #include <linux/log2.h>
  19 #include <linux/typecheck.h>
  20 #include <linux/printk.h>
  21 #include <linux/dynamic_debug.h>
  22 #include <asm/byteorder.h>
  23 #include <asm/bug.h>
  24
  25 #define USHRT_MAX       ((u16)(~0U))
  26 #define SHRT_MAX        ((s16)(USHRT_MAX>>1))
  27 #define SHRT_MIN        ((s16)(-SHRT_MAX - 1))
  28 #define INT_MAX         ((int)(~0U>>1))
  29 #define INT_MIN         (-INT_MAX - 1)
  30 #define UINT_MAX        (~0U)
  31 #define LONG_MAX        ((long)(~0UL>>1))
  32 #define LONG_MIN        (-LONG_MAX - 1)
  33 #define ULONG_MAX       (~0UL)
  34 #define LLONG_MAX       ((long long)(~0ULL>>1))
  35 #define LLONG_MIN       (-LLONG_MAX - 1)
  36 #define ULLONG_MAX      (~0ULL)
  37
  38 #define STACK_MAGIC     0xdeadbeef
  39
  40 #define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
  41 #define __ALIGN_MASK(x, mask)   __ALIGN_KERNEL_MASK((x), (mask))
  42 #define PTR_ALIGN(p, a)         ((typeof(p))ALIGN((unsigned long)(p), (a)))
  43 #define IS_ALIGNED(x, a)                (((x) & ((typeof(x))(a) - 1)) == 0)
  44
  45 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  46
  47 /*
  48  * This looks more complex than it should be. But we need to
  49  * get the type for the ~ right in round_down (it needs to be
  50  * as wide as the result!), and we want to evaluate the macro
  51  * arguments just once each.
  52  */
  53 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
  54 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
  55 #define round_down(x, y) ((x) & ~__round_mask(x, y))
  56
  57 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  58 #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  59 #define DIV_ROUND_UP_ULL(ll,d) \
  60         ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
  61
  62 #if BITS_PER_LONG == 32
  63 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
  64 #else
  65 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
  66 #endif
  67
  68 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
  69 #define roundup(x, y) (                                 \
  70 {                                                       \
  71         const typeof(y) __y = y;                        \
  72         (((x) + (__y - 1)) / __y) * __y;                \
  73 }                                                       \
  74 )
  75 #define rounddown(x, y) (                               \
  76 {                                                       \
  77         typeof(x) __x = (x);                            \
  78         __x - (__x % (y));                              \
  79 }                                                       \
  80 )
  81 #define DIV_ROUND_CLOSEST(x, divisor)(                  \
  82 {                                                       \
  83         typeof(divisor) __divisor = divisor;            \
  84         (((x) + ((__divisor) / 2)) / (__divisor));      \
  85 }                                                       \
  86 )
  87
  88 #define _RET_IP_                (unsigned long)__builtin_return_address(0)
  89 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
  90
  91 #ifdef CONFIG_LBDAF
  92 # include <asm/div64.h>
  93 # define sector_div(a, b) do_div(a, b)
  94 #else
  95 # define sector_div(n, b)( \
  96 { \
  97         int _res; \
  98         _res = (n) % (b); \
  99         (n) /= (b); \
 100         _res; \
 101 } \
 102 )
 103 #endif
 104
 105 /**
 106  * upper_32_bits - return bits 32-63 of a number
 107  * @n: the number we're accessing
 108  *
 109  * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
 110  * the "right shift count >= width of type" warning when that quantity is
 111  * 32-bits.
 112  */
 113 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
 114
 115 /**
 116  * lower_32_bits - return bits 0-31 of a number
 117  * @n: the number we're accessing
 118  */
 119 #define lower_32_bits(n) ((u32)(n))
 120
 121 struct completion;
 122 struct pt_regs;
 123 struct user;
 124
 125 #ifdef CONFIG_PREEMPT_VOLUNTARY
 126 extern int _cond_resched(void);
 127 # define might_resched() _cond_resched()
 128 #else
 129 # define might_resched() do { } while (0)
 130 #endif
 131
 132 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 133   void __might_sleep(const char *file, int line, int preempt_offset);
 134 /**
 135  * might_sleep - annotation for functions that can sleep
 136  *
 137  * this macro will print a stack trace if it is executed in an atomic
 138  * context (spinlock, irq-handler, ...).
 139  *
 140  * This is a useful debugging help to be able to catch problems early and not
 141  * be bitten later when the calling function happens to sleep when it is not
 142  * supposed to.
 143  */
 144 # define might_sleep() \
 145         do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 146 #else
 147   static inline void __might_sleep(const char *file, int line,
 148                                    int preempt_offset) { }
 149 # define might_sleep() do { might_resched(); } while (0)
 150 #endif
 151
 152 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 153
 154 /*
 155  * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
 156  * input types abs() returns a signed long.
 157  * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
 158  * for those.
 159  */
 160 #define abs(x) ({                                               \
 161                 long ret;                                       \
 162                 if (sizeof(x) == sizeof(long)) {                \
 163                         long __x = (x);                         \
 164                         ret = (__x < 0) ? -__x : __x;           \
 165                 } else {                                        \
 166                         int __x = (x);                          \
 167                         ret = (__x < 0) ? -__x : __x;           \
 168                 }                                               \
 169                 ret;                                            \
 170         })
 171
 172 #define abs64(x) ({                             \
 173                 s64 __x = (x);                  \
 174                 (__x < 0) ? -__x : __x;         \
 175         })
 176
 177 #ifdef CONFIG_PROVE_LOCKING
 178 void might_fault(void);
 179 #else
 180 static inline void might_fault(void)
 181 {
 182         might_sleep();
 183 }
 184 #endif
 185
 186 extern struct atomic_notifier_head panic_notifier_list;
 187 extern long (*panic_blink)(int state);
 188 NORET_TYPE void panic(const char * fmt, ...)
 189         __attribute__ ((NORET_AND format (printf, 1, 2))) __cold;
 190 extern void oops_enter(void);
 191 extern void oops_exit(void);
 192 void print_oops_end_marker(void);
 193 extern int oops_may_print(void);
 194 NORET_TYPE void do_exit(long error_code)
 195         ATTRIB_NORET;
 196 NORET_TYPE void complete_and_exit(struct completion *, long)
 197         ATTRIB_NORET;
 198
 199 /* Internal, do not use. */
 200 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 201 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 202
 203 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 204 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 205 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 206 {
 207         /*
 208          * We want to shortcut function call, but
 209          * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 210          */
 211         if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 212             __alignof__(unsigned long) == __alignof__(unsigned long long))
 213                 return kstrtoull(s, base, (unsigned long long *)res);
 214         else
 215                 return _kstrtoul(s, base, res);
 216 }
 217
 218 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 219 {
 220         /*
 221          * We want to shortcut function call, but
 222          * __builtin_types_compatible_p(long, long long) = 0.
 223          */
 224         if (sizeof(long) == sizeof(long long) &&
 225             __alignof__(long) == __alignof__(long long))
 226                 return kstrtoll(s, base, (long long *)res);
 227         else
 228                 return _kstrtol(s, base, res);
 229 }
 230
 231 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 232 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 233
 234 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 235 {
 236         return kstrtoull(s, base, res);
 237 }
 238
 239 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 240 {
 241         return kstrtoll(s, base, res);
 242 }
 243
 244 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 245 {
 246         return kstrtouint(s, base, res);
 247 }
 248
 249 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 250 {
 251         return kstrtoint(s, base, res);
 252 }
 253
 254 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 255 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 256 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 257 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 258
 259 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 260 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 261 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 262 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 263 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 264 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 265 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 266 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 267 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 268 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 269
 270 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 271 {
 272         return kstrtoull_from_user(s, count, base, res);
 273 }
 274
 275 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 276 {
 277         return kstrtoll_from_user(s, count, base, res);
 278 }
 279
 280 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 281 {
 282         return kstrtouint_from_user(s, count, base, res);
 283 }
 284
 285 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 286 {
 287         return kstrtoint_from_user(s, count, base, res);
 288 }
 289
 290 /* Obsolete, do not use.  Use kstrto<foo> instead */
 291
 292 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 293 extern long simple_strtol(const char *,char **,unsigned int);
 294 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 295 extern long long simple_strtoll(const char *,char **,unsigned int);
 296 #define strict_strtoul  kstrtoul
 297 #define strict_strtol   kstrtol
 298 #define strict_strtoull kstrtoull
 299 #define strict_strtoll  kstrtoll
 300
 301 /* lib/printf utilities */
 302
 303 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 304 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 305 extern __printf(3, 4)
 306 int snprintf(char *buf, size_t size, const char *fmt, ...);
 307 extern __printf(3, 0)
 308 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 309 extern __printf(3, 4)
 310 int scnprintf(char *buf, size_t size, const char *fmt, ...);
 311 extern __printf(3, 0)
 312 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 313 extern __printf(2, 3)
 314 char *kasprintf(gfp_t gfp, const char *fmt, ...);
 315 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 316
 317 extern int sscanf(const char *, const char *, ...)
 318         __attribute__ ((format (scanf, 2, 3)));
 319 extern int vsscanf(const char *, const char *, va_list)
 320         __attribute__ ((format (scanf, 2, 0)));
 321
 322 extern int get_option(char **str, int *pint);
 323 extern char *get_options(const char *str, int nints, int *ints);
 324 extern unsigned long long memparse(const char *ptr, char **retptr);
 325
 326 extern int core_kernel_text(unsigned long addr);
 327 extern int core_kernel_data(unsigned long addr);
 328 extern int __kernel_text_address(unsigned long addr);
 329 extern int kernel_text_address(unsigned long addr);
 330 extern int func_ptr_is_kernel_text(void *ptr);
 331
 332 struct pid;
 333 extern struct pid *session_of_pgrp(struct pid *pgrp);
 334
 335 unsigned long int_sqrt(unsigned long);
 336
 337 extern void bust_spinlocks(int yes);
 338 extern void wake_up_klogd(void);
 339 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 340 extern int panic_timeout;
 341 extern int panic_on_oops;
 342 extern int panic_on_unrecovered_nmi;
 343 extern int panic_on_io_nmi;
 344 extern const char *print_tainted(void);
 345 extern void add_taint(unsigned flag);
 346 extern int test_taint(unsigned flag);
 347 extern unsigned long get_taint(void);
 348 extern int root_mountflags;
 349
 350 extern bool early_boot_irqs_disabled;
 351
 352 /* Values used for system_state */
 353 extern enum system_states {
 354         SYSTEM_BOOTING,
 355         SYSTEM_RUNNING,
 356         SYSTEM_HALT,
 357         SYSTEM_POWER_OFF,
 358         SYSTEM_RESTART,
 359         SYSTEM_SUSPEND_DISK,
 360 } system_state;
 361
 362 #define TAINT_PROPRIETARY_MODULE        0
 363 #define TAINT_FORCED_MODULE             1
 364 #define TAINT_UNSAFE_SMP                2
 365 #define TAINT_FORCED_RMMOD              3
 366 #define TAINT_MACHINE_CHECK             4
 367 #define TAINT_BAD_PAGE                  5
 368 #define TAINT_USER                      6
 369 #define TAINT_DIE                       7
 370 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
 371 #define TAINT_WARN                      9
 372 #define TAINT_CRAP                      10
 373 #define TAINT_FIRMWARE_WORKAROUND       11
 374
 375 extern const char hex_asc[];
 376 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 377 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 378
 379 static inline char *hex_byte_pack(char *buf, u8 byte)
 380 {
 381         *buf++ = hex_asc_hi(byte);
 382         *buf++ = hex_asc_lo(byte);
 383         return buf;
 384 }
 385
 386 static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 387 {
 388         return hex_byte_pack(buf, byte);
 389 }
 390
 391 extern int hex_to_bin(char ch);
 392 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 393
 394 /*
 395  * General tracing related utility functions - trace_printk(),
 396  * tracing_on/tracing_off and tracing_start()/tracing_stop
 397  *
 398  * Use tracing_on/tracing_off when you want to quickly turn on or off
 399  * tracing. It simply enables or disables the recording of the trace events.
 400  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 401  * file, which gives a means for the kernel and userspace to interact.
 402  * Place a tracing_off() in the kernel where you want tracing to end.
 403  * From user space, examine the trace, and then echo 1 > tracing_on
 404  * to continue tracing.
 405  *
 406  * tracing_stop/tracing_start has slightly more overhead. It is used
 407  * by things like suspend to ram where disabling the recording of the
 408  * trace is not enough, but tracing must actually stop because things
 409  * like calling smp_processor_id() may crash the system.
 410  *
 411  * Most likely, you want to use tracing_on/tracing_off.
 412  */
 413 #ifdef CONFIG_RING_BUFFER
 414 void tracing_on(void);
 415 void tracing_off(void);
 416 /* trace_off_permanent stops recording with no way to bring it back */
 417 void tracing_off_permanent(void);
 418 int tracing_is_on(void);
 419 #else
 420 static inline void tracing_on(void) { }
 421 static inline void tracing_off(void) { }
 422 static inline void tracing_off_permanent(void) { }
 423 static inline int tracing_is_on(void) { return 0; }
 424 #endif
 425
 426 enum ftrace_dump_mode {
 427         DUMP_NONE,
 428         DUMP_ALL,
 429         DUMP_ORIG,
 430 };
 431
 432 #ifdef CONFIG_TRACING
 433 extern void tracing_start(void);
 434 extern void tracing_stop(void);
 435 extern void ftrace_off_permanent(void);
 436
 437 static inline __printf(1, 2)
 438 void ____trace_printk_check_format(const char *fmt, ...)
 439 {
 440 }
 441 #define __trace_printk_check_format(fmt, args...)                       \
 442 do {                                                                    \
 443         if (0)                                                          \
 444                 ____trace_printk_check_format(fmt, ##args);             \
 445 } while (0)
 446
 447 /**
 448  * trace_printk - printf formatting in the ftrace buffer
 449  * @fmt: the printf format for printing
 450  *
 451  * Note: __trace_printk is an internal function for trace_printk and
 452  *       the @ip is passed in via the trace_printk macro.
 453  *
 454  * This function allows a kernel developer to debug fast path sections
 455  * that printk is not appropriate for. By scattering in various
 456  * printk like tracing in the code, a developer can quickly see
 457  * where problems are occurring.
 458  *
 459  * This is intended as a debugging tool for the developer only.
 460  * Please refrain from leaving trace_printks scattered around in
 461  * your code.
 462  */
 463
 464 #define trace_printk(fmt, args...)                                      \
 465 do {                                                                    \
 466         __trace_printk_check_format(fmt, ##args);                       \
 467         if (__builtin_constant_p(fmt)) {                                \
 468                 static const char *trace_printk_fmt                     \
 469                   __attribute__((section("__trace_printk_fmt"))) =      \
 470                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 471                                                                         \
 472                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 473         } else                                                          \
 474                 __trace_printk(_THIS_IP_, fmt, ##args);         \
 475 } while (0)
 476
 477 extern __printf(2, 3)
 478 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 479
 480 extern __printf(2, 3)
 481 int __trace_printk(unsigned long ip, const char *fmt, ...);
 482
 483 extern void trace_dump_stack(void);
 484
 485 /*
 486  * The double __builtin_constant_p is because gcc will give us an error
 487  * if we try to allocate the static variable to fmt if it is not a
 488  * constant. Even with the outer if statement.
 489  */
 490 #define ftrace_vprintk(fmt, vargs)                                      \
 491 do {                                                                    \
 492         if (__builtin_constant_p(fmt)) {                                \
 493                 static const char *trace_printk_fmt                     \
 494                   __attribute__((section("__trace_printk_fmt"))) =      \
 495                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 496                                                                         \
 497                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 498         } else                                                          \
 499                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 500 } while (0)
 501
 502 extern int
 503 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 504
 505 extern int
 506 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 507
 508 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 509 #else
 510 static inline __printf(1, 2)
 511 int trace_printk(const char *fmt, ...);
 512
 513 static inline void tracing_start(void) { }
 514 static inline void tracing_stop(void) { }
 515 static inline void ftrace_off_permanent(void) { }
 516 static inline void trace_dump_stack(void) { }
 517 static inline int
 518 trace_printk(const char *fmt, ...)
 519 {
 520         return 0;
 521 }
 522 static inline int
 523 ftrace_vprintk(const char *fmt, va_list ap)
 524 {
 525         return 0;
 526 }
 527 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 528 #endif /* CONFIG_TRACING */
 529
 530 /*
 531  * min()/max()/clamp() macros that also do
 532  * strict type-checking.. See the
 533  * "unnecessary" pointer comparison.
 534  */
 535 #define min(x, y) ({                            \
 536         typeof(x) _min1 = (x);                  \
 537         typeof(y) _min2 = (y);                  \
 538         (void) (&_min1 == &_min2);              \
 539         _min1 < _min2 ? _min1 : _min2; })
 540
 541 #define max(x, y) ({                            \
 542         typeof(x) _max1 = (x);                  \
 543         typeof(y) _max2 = (y);                  \
 544         (void) (&_max1 == &_max2);              \
 545         _max1 > _max2 ? _max1 : _max2; })
 546
 547 #define min3(x, y, z) ({                        \
 548         typeof(x) _min1 = (x);                  \
 549         typeof(y) _min2 = (y);                  \
 550         typeof(z) _min3 = (z);                  \
 551         (void) (&_min1 == &_min2);              \
 552         (void) (&_min1 == &_min3);              \
 553         _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 554                 (_min2 < _min3 ? _min2 : _min3); })
 555
 556 #define max3(x, y, z) ({                        \
 557         typeof(x) _max1 = (x);                  \
 558         typeof(y) _max2 = (y);                  \
 559         typeof(z) _max3 = (z);                  \
 560         (void) (&_max1 == &_max2);              \
 561         (void) (&_max1 == &_max3);              \
 562         _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 563                 (_max2 > _max3 ? _max2 : _max3); })
 564
 565 /**
 566  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 567  * @x: value1
 568  * @y: value2
 569  */
 570 #define min_not_zero(x, y) ({                   \
 571         typeof(x) __x = (x);                    \
 572         typeof(y) __y = (y);                    \
 573         __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 574
 575 /**
 576  * clamp - return a value clamped to a given range with strict typechecking
 577  * @val: current value
 578  * @min: minimum allowable value
 579  * @max: maximum allowable value
 580  *
 581  * This macro does strict typechecking of min/max to make sure they are of the
 582  * same type as val.  See the unnecessary pointer comparisons.
 583  */
 584 #define clamp(val, min, max) ({                 \
 585         typeof(val) __val = (val);              \
 586         typeof(min) __min = (min);              \
 587         typeof(max) __max = (max);              \
 588         (void) (&__val == &__min);              \
 589         (void) (&__val == &__max);              \
 590         __val = __val < __min ? __min: __val;   \
 591         __val > __max ? __max: __val; })
 592
 593 /*
 594  * ..and if you can't take the strict
 595  * types, you can specify one yourself.
 596  *
 597  * Or not use min/max/clamp at all, of course.
 598  */
 599 #define min_t(type, x, y) ({                    \
 600         type __min1 = (x);                      \
 601         type __min2 = (y);                      \
 602         __min1 < __min2 ? __min1: __min2; })
 603
 604 #define max_t(type, x, y) ({                    \
 605         type __max1 = (x);                      \
 606         type __max2 = (y);                      \
 607         __max1 > __max2 ? __max1: __max2; })
 608
 609 /**
 610  * clamp_t - return a value clamped to a given range using a given type
 611  * @type: the type of variable to use
 612  * @val: current value
 613  * @min: minimum allowable value
 614  * @max: maximum allowable value
 615  *
 616  * This macro does no typechecking and uses temporary variables of type
 617  * 'type' to make all the comparisons.
 618  */
 619 #define clamp_t(type, val, min, max) ({         \
 620         type __val = (val);                     \
 621         type __min = (min);                     \
 622         type __max = (max);                     \
 623         __val = __val < __min ? __min: __val;   \
 624         __val > __max ? __max: __val; })
 625
 626 /**
 627  * clamp_val - return a value clamped to a given range using val's type
 628  * @val: current value
 629  * @min: minimum allowable value
 630  * @max: maximum allowable value
 631  *
 632  * This macro does no typechecking and uses temporary variables of whatever
 633  * type the input argument 'val' is.  This is useful when val is an unsigned
 634  * type and min and max are literals that will otherwise be assigned a signed
 635  * integer type.
 636  */
 637 #define clamp_val(val, min, max) ({             \
 638         typeof(val) __val = (val);              \
 639         typeof(val) __min = (min);              \
 640         typeof(val) __max = (max);              \
 641         __val = __val < __min ? __min: __val;   \
 642         __val > __max ? __max: __val; })
 643
 644
 645 /*
 646  * swap - swap value of @a and @b
 647  */
 648 #define swap(a, b) \
 649         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 650
 651 /**
 652  * container_of - cast a member of a structure out to the containing structure
 653  * @ptr:        the pointer to the member.
 654  * @type:       the type of the container struct this is embedded in.
 655  * @member:     the name of the member within the struct.
 656  *
 657  */
 658 #define container_of(ptr, type, member) ({                      \
 659         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 660         (type *)( (char *)__mptr - offsetof(type,member) );})
 661
 662 #ifdef __CHECKER__
 663 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)
 664 #define BUILD_BUG_ON_ZERO(e) (0)
 665 #define BUILD_BUG_ON_NULL(e) ((void*)0)
 666 #define BUILD_BUG_ON(condition)
 667 #else /* __CHECKER__ */
 668
 669 /* Force a compilation error if a constant expression is not a power of 2 */
 670 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
 671         BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
 672
 673 /* Force a compilation error if condition is true, but also produce a
 674    result (of value 0 and type size_t), so the expression can be used
 675    e.g. in a structure initializer (or where-ever else comma expressions
 676    aren't permitted). */
 677 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 678 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
 679
 680 /**
 681  * BUILD_BUG_ON - break compile if a condition is true.
 682  * @condition: the condition which the compiler should know is false.
 683  *
 684  * If you have some code which relies on certain constants being equal, or
 685  * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 686  * detect if someone changes it.
 687  *
 688  * The implementation uses gcc's reluctance to create a negative array, but
 689  * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 690  * to inline functions).  So as a fallback we use the optimizer; if it can't
 691  * prove the condition is false, it will cause a link error on the undefined
 692  * "__build_bug_on_failed".  This error message can be harder to track down
 693  * though, hence the two different methods.
 694  */
 695 #ifndef __OPTIMIZE__
 696 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 697 #else
 698 extern int __build_bug_on_failed;
 699 #define BUILD_BUG_ON(condition)                                 \
 700         do {                                                    \
 701                 ((void)sizeof(char[1 - 2*!!(condition)]));      \
 702                 if (condition) __build_bug_on_failed = 1;       \
 703         } while(0)
 704 #endif
 705 #endif  /* __CHECKER__ */
 706
 707 /* Trap pasters of __FUNCTION__ at compile-time */
 708 #define __FUNCTION__ (__func__)
 709
 710 /* This helps us to avoid #ifdef CONFIG_NUMA */
 711 #ifdef CONFIG_NUMA
 712 #define NUMA_BUILD 1
 713 #else
 714 #define NUMA_BUILD 0
 715 #endif
 716
 717 /* This helps us avoid #ifdef CONFIG_COMPACTION */
 718 #ifdef CONFIG_COMPACTION
 719 #define COMPACTION_BUILD 1
 720 #else
 721 #define COMPACTION_BUILD 0
 722 #endif
 723
 724 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 725 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 726 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 727 #endif
 728
 729 struct sysinfo;
 730 extern int do_sysinfo(struct sysinfo *info);
 731
 732 #endif /* __KERNEL__ */
 733
 734 #define SI_LOAD_SHIFT   16
 735 struct sysinfo {
 736         long uptime;                    /* Seconds since boot */
 737         unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 738         unsigned long totalram;         /* Total usable main memory size */
 739         unsigned long freeram;          /* Available memory size */
 740         unsigned long sharedram;        /* Amount of shared memory */
 741         unsigned long bufferram;        /* Memory used by buffers */
 742         unsigned long totalswap;        /* Total swap space size */
 743         unsigned long freeswap;         /* swap space still available */
 744         unsigned short procs;           /* Number of current processes */
 745         unsigned short pad;             /* explicit padding for m68k */
 746         unsigned long totalhigh;        /* Total high memory size */
 747         unsigned long freehigh;         /* Available high memory size */
 748         unsigned int mem_unit;          /* Memory unit size in bytes */
 749         char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 750 };
 751
 752 #endif