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 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 291 extern long simple_strtol(const char *,char **,unsigned int);
 292 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 293 extern long long simple_strtoll(const char *,char **,unsigned int);
 294 #define strict_strtoul  kstrtoul
 295 #define strict_strtol   kstrtol
 296 #define strict_strtoull kstrtoull
 297 #define strict_strtoll  kstrtoll
 298
 299 extern int sprintf(char * buf, const char * fmt, ...)
 300         __attribute__ ((format (printf, 2, 3)));
 301 extern int vsprintf(char *buf, const char *, va_list)
 302         __attribute__ ((format (printf, 2, 0)));
 303 extern int snprintf(char * buf, size_t size, const char * fmt, ...)
 304         __attribute__ ((format (printf, 3, 4)));
 305 extern int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 306         __attribute__ ((format (printf, 3, 0)));
 307 extern int scnprintf(char * buf, size_t size, const char * fmt, ...)
 308         __attribute__ ((format (printf, 3, 4)));
 309 extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 310         __attribute__ ((format (printf, 3, 0)));
 311 extern char *kasprintf(gfp_t gfp, const char *fmt, ...)
 312         __attribute__ ((format (printf, 2, 3)));
 313 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 314
 315 extern int sscanf(const char *, const char *, ...)
 316         __attribute__ ((format (scanf, 2, 3)));
 317 extern int vsscanf(const char *, const char *, va_list)
 318         __attribute__ ((format (scanf, 2, 0)));
 319
 320 extern int get_option(char **str, int *pint);
 321 extern char *get_options(const char *str, int nints, int *ints);
 322 extern unsigned long long memparse(const char *ptr, char **retptr);
 323
 324 extern int core_kernel_text(unsigned long addr);
 325 extern int core_kernel_data(unsigned long addr);
 326 extern int __kernel_text_address(unsigned long addr);
 327 extern int kernel_text_address(unsigned long addr);
 328 extern int func_ptr_is_kernel_text(void *ptr);
 329
 330 struct pid;
 331 extern struct pid *session_of_pgrp(struct pid *pgrp);
 332
 333 unsigned long int_sqrt(unsigned long);
 334
 335 extern void bust_spinlocks(int yes);
 336 extern void wake_up_klogd(void);
 337 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 338 extern int panic_timeout;
 339 extern int panic_on_oops;
 340 extern int panic_on_unrecovered_nmi;
 341 extern int panic_on_io_nmi;
 342 extern const char *print_tainted(void);
 343 extern void add_taint(unsigned flag);
 344 extern int test_taint(unsigned flag);
 345 extern unsigned long get_taint(void);
 346 extern int root_mountflags;
 347
 348 extern bool early_boot_irqs_disabled;
 349
 350 /* Values used for system_state */
 351 extern enum system_states {
 352         SYSTEM_BOOTING,
 353         SYSTEM_RUNNING,
 354         SYSTEM_HALT,
 355         SYSTEM_POWER_OFF,
 356         SYSTEM_RESTART,
 357         SYSTEM_SUSPEND_DISK,
 358 } system_state;
 359
 360 #define TAINT_PROPRIETARY_MODULE        0
 361 #define TAINT_FORCED_MODULE             1
 362 #define TAINT_UNSAFE_SMP                2
 363 #define TAINT_FORCED_RMMOD              3
 364 #define TAINT_MACHINE_CHECK             4
 365 #define TAINT_BAD_PAGE                  5
 366 #define TAINT_USER                      6
 367 #define TAINT_DIE                       7
 368 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
 369 #define TAINT_WARN                      9
 370 #define TAINT_CRAP                      10
 371 #define TAINT_FIRMWARE_WORKAROUND       11
 372
 373 extern const char hex_asc[];
 374 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 375 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 376
 377 static inline char *pack_hex_byte(char *buf, u8 byte)
 378 {
 379         *buf++ = hex_asc_hi(byte);
 380         *buf++ = hex_asc_lo(byte);
 381         return buf;
 382 }
 383
 384 extern int hex_to_bin(char ch);
 385 extern void hex2bin(u8 *dst, const char *src, size_t count);
 386
 387 /*
 388  * General tracing related utility functions - trace_printk(),
 389  * tracing_on/tracing_off and tracing_start()/tracing_stop
 390  *
 391  * Use tracing_on/tracing_off when you want to quickly turn on or off
 392  * tracing. It simply enables or disables the recording of the trace events.
 393  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 394  * file, which gives a means for the kernel and userspace to interact.
 395  * Place a tracing_off() in the kernel where you want tracing to end.
 396  * From user space, examine the trace, and then echo 1 > tracing_on
 397  * to continue tracing.
 398  *
 399  * tracing_stop/tracing_start has slightly more overhead. It is used
 400  * by things like suspend to ram where disabling the recording of the
 401  * trace is not enough, but tracing must actually stop because things
 402  * like calling smp_processor_id() may crash the system.
 403  *
 404  * Most likely, you want to use tracing_on/tracing_off.
 405  */
 406 #ifdef CONFIG_RING_BUFFER
 407 void tracing_on(void);
 408 void tracing_off(void);
 409 /* trace_off_permanent stops recording with no way to bring it back */
 410 void tracing_off_permanent(void);
 411 int tracing_is_on(void);
 412 #else
 413 static inline void tracing_on(void) { }
 414 static inline void tracing_off(void) { }
 415 static inline void tracing_off_permanent(void) { }
 416 static inline int tracing_is_on(void) { return 0; }
 417 #endif
 418
 419 enum ftrace_dump_mode {
 420         DUMP_NONE,
 421         DUMP_ALL,
 422         DUMP_ORIG,
 423 };
 424
 425 #ifdef CONFIG_TRACING
 426 extern void tracing_start(void);
 427 extern void tracing_stop(void);
 428 extern void ftrace_off_permanent(void);
 429
 430 static inline void __attribute__ ((format (printf, 1, 2)))
 431 ____trace_printk_check_format(const char *fmt, ...)
 432 {
 433 }
 434 #define __trace_printk_check_format(fmt, args...)                       \
 435 do {                                                                    \
 436         if (0)                                                          \
 437                 ____trace_printk_check_format(fmt, ##args);             \
 438 } while (0)
 439
 440 /**
 441  * trace_printk - printf formatting in the ftrace buffer
 442  * @fmt: the printf format for printing
 443  *
 444  * Note: __trace_printk is an internal function for trace_printk and
 445  *       the @ip is passed in via the trace_printk macro.
 446  *
 447  * This function allows a kernel developer to debug fast path sections
 448  * that printk is not appropriate for. By scattering in various
 449  * printk like tracing in the code, a developer can quickly see
 450  * where problems are occurring.
 451  *
 452  * This is intended as a debugging tool for the developer only.
 453  * Please refrain from leaving trace_printks scattered around in
 454  * your code.
 455  */
 456
 457 #define trace_printk(fmt, args...)                                      \
 458 do {                                                                    \
 459         __trace_printk_check_format(fmt, ##args);                       \
 460         if (__builtin_constant_p(fmt)) {                                \
 461                 static const char *trace_printk_fmt                     \
 462                   __attribute__((section("__trace_printk_fmt"))) =      \
 463                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 464                                                                         \
 465                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 466         } else                                                          \
 467                 __trace_printk(_THIS_IP_, fmt, ##args);         \
 468 } while (0)
 469
 470 extern int
 471 __trace_bprintk(unsigned long ip, const char *fmt, ...)
 472         __attribute__ ((format (printf, 2, 3)));
 473
 474 extern int
 475 __trace_printk(unsigned long ip, const char *fmt, ...)
 476         __attribute__ ((format (printf, 2, 3)));
 477
 478 extern void trace_dump_stack(void);
 479
 480 /*
 481  * The double __builtin_constant_p is because gcc will give us an error
 482  * if we try to allocate the static variable to fmt if it is not a
 483  * constant. Even with the outer if statement.
 484  */
 485 #define ftrace_vprintk(fmt, vargs)                                      \
 486 do {                                                                    \
 487         if (__builtin_constant_p(fmt)) {                                \
 488                 static const char *trace_printk_fmt                     \
 489                   __attribute__((section("__trace_printk_fmt"))) =      \
 490                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 491                                                                         \
 492                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 493         } else                                                          \
 494                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 495 } while (0)
 496
 497 extern int
 498 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 499
 500 extern int
 501 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 502
 503 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 504 #else
 505 static inline int
 506 trace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
 507
 508 static inline void tracing_start(void) { }
 509 static inline void tracing_stop(void) { }
 510 static inline void ftrace_off_permanent(void) { }
 511 static inline void trace_dump_stack(void) { }
 512 static inline int
 513 trace_printk(const char *fmt, ...)
 514 {
 515         return 0;
 516 }
 517 static inline int
 518 ftrace_vprintk(const char *fmt, va_list ap)
 519 {
 520         return 0;
 521 }
 522 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 523 #endif /* CONFIG_TRACING */
 524
 525 /*
 526  * min()/max()/clamp() macros that also do
 527  * strict type-checking.. See the
 528  * "unnecessary" pointer comparison.
 529  */
 530 #define min(x, y) ({                            \
 531         typeof(x) _min1 = (x);                  \
 532         typeof(y) _min2 = (y);                  \
 533         (void) (&_min1 == &_min2);              \
 534         _min1 < _min2 ? _min1 : _min2; })
 535
 536 #define max(x, y) ({                            \
 537         typeof(x) _max1 = (x);                  \
 538         typeof(y) _max2 = (y);                  \
 539         (void) (&_max1 == &_max2);              \
 540         _max1 > _max2 ? _max1 : _max2; })
 541
 542 #define min3(x, y, z) ({                        \
 543         typeof(x) _min1 = (x);                  \
 544         typeof(y) _min2 = (y);                  \
 545         typeof(z) _min3 = (z);                  \
 546         (void) (&_min1 == &_min2);              \
 547         (void) (&_min1 == &_min3);              \
 548         _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 549                 (_min2 < _min3 ? _min2 : _min3); })
 550
 551 #define max3(x, y, z) ({                        \
 552         typeof(x) _max1 = (x);                  \
 553         typeof(y) _max2 = (y);                  \
 554         typeof(z) _max3 = (z);                  \
 555         (void) (&_max1 == &_max2);              \
 556         (void) (&_max1 == &_max3);              \
 557         _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 558                 (_max2 > _max3 ? _max2 : _max3); })
 559
 560 /**
 561  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 562  * @x: value1
 563  * @y: value2
 564  */
 565 #define min_not_zero(x, y) ({                   \
 566         typeof(x) __x = (x);                    \
 567         typeof(y) __y = (y);                    \
 568         __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 569
 570 /**
 571  * clamp - return a value clamped to a given range with strict typechecking
 572  * @val: current value
 573  * @min: minimum allowable value
 574  * @max: maximum allowable value
 575  *
 576  * This macro does strict typechecking of min/max to make sure they are of the
 577  * same type as val.  See the unnecessary pointer comparisons.
 578  */
 579 #define clamp(val, min, max) ({                 \
 580         typeof(val) __val = (val);              \
 581         typeof(min) __min = (min);              \
 582         typeof(max) __max = (max);              \
 583         (void) (&__val == &__min);              \
 584         (void) (&__val == &__max);              \
 585         __val = __val < __min ? __min: __val;   \
 586         __val > __max ? __max: __val; })
 587
 588 /*
 589  * ..and if you can't take the strict
 590  * types, you can specify one yourself.
 591  *
 592  * Or not use min/max/clamp at all, of course.
 593  */
 594 #define min_t(type, x, y) ({                    \
 595         type __min1 = (x);                      \
 596         type __min2 = (y);                      \
 597         __min1 < __min2 ? __min1: __min2; })
 598
 599 #define max_t(type, x, y) ({                    \
 600         type __max1 = (x);                      \
 601         type __max2 = (y);                      \
 602         __max1 > __max2 ? __max1: __max2; })
 603
 604 /**
 605  * clamp_t - return a value clamped to a given range using a given type
 606  * @type: the type of variable to use
 607  * @val: current value
 608  * @min: minimum allowable value
 609  * @max: maximum allowable value
 610  *
 611  * This macro does no typechecking and uses temporary variables of type
 612  * 'type' to make all the comparisons.
 613  */
 614 #define clamp_t(type, val, min, max) ({         \
 615         type __val = (val);                     \
 616         type __min = (min);                     \
 617         type __max = (max);                     \
 618         __val = __val < __min ? __min: __val;   \
 619         __val > __max ? __max: __val; })
 620
 621 /**
 622  * clamp_val - return a value clamped to a given range using val's type
 623  * @val: current value
 624  * @min: minimum allowable value
 625  * @max: maximum allowable value
 626  *
 627  * This macro does no typechecking and uses temporary variables of whatever
 628  * type the input argument 'val' is.  This is useful when val is an unsigned
 629  * type and min and max are literals that will otherwise be assigned a signed
 630  * integer type.
 631  */
 632 #define clamp_val(val, min, max) ({             \
 633         typeof(val) __val = (val);              \
 634         typeof(val) __min = (min);              \
 635         typeof(val) __max = (max);              \
 636         __val = __val < __min ? __min: __val;   \
 637         __val > __max ? __max: __val; })
 638
 639
 640 /*
 641  * swap - swap value of @a and @b
 642  */
 643 #define swap(a, b) \
 644         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 645
 646 /**
 647  * container_of - cast a member of a structure out to the containing structure
 648  * @ptr:        the pointer to the member.
 649  * @type:       the type of the container struct this is embedded in.
 650  * @member:     the name of the member within the struct.
 651  *
 652  */
 653 #define container_of(ptr, type, member) ({                      \
 654         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 655         (type *)( (char *)__mptr - offsetof(type,member) );})
 656
 657 #ifdef __CHECKER__
 658 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)
 659 #define BUILD_BUG_ON_ZERO(e) (0)
 660 #define BUILD_BUG_ON_NULL(e) ((void*)0)
 661 #define BUILD_BUG_ON(condition)
 662 #else /* __CHECKER__ */
 663
 664 /* Force a compilation error if a constant expression is not a power of 2 */
 665 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
 666         BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
 667
 668 /* Force a compilation error if condition is true, but also produce a
 669    result (of value 0 and type size_t), so the expression can be used
 670    e.g. in a structure initializer (or where-ever else comma expressions
 671    aren't permitted). */
 672 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 673 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
 674
 675 /**
 676  * BUILD_BUG_ON - break compile if a condition is true.
 677  * @condition: the condition which the compiler should know is false.
 678  *
 679  * If you have some code which relies on certain constants being equal, or
 680  * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 681  * detect if someone changes it.
 682  *
 683  * The implementation uses gcc's reluctance to create a negative array, but
 684  * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 685  * to inline functions).  So as a fallback we use the optimizer; if it can't
 686  * prove the condition is false, it will cause a link error on the undefined
 687  * "__build_bug_on_failed".  This error message can be harder to track down
 688  * though, hence the two different methods.
 689  */
 690 #ifndef __OPTIMIZE__
 691 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 692 #else
 693 extern int __build_bug_on_failed;
 694 #define BUILD_BUG_ON(condition)                                 \
 695         do {                                                    \
 696                 ((void)sizeof(char[1 - 2*!!(condition)]));      \
 697                 if (condition) __build_bug_on_failed = 1;       \
 698         } while(0)
 699 #endif
 700 #endif  /* __CHECKER__ */
 701
 702 /* Trap pasters of __FUNCTION__ at compile-time */
 703 #define __FUNCTION__ (__func__)
 704
 705 /* This helps us to avoid #ifdef CONFIG_NUMA */
 706 #ifdef CONFIG_NUMA
 707 #define NUMA_BUILD 1
 708 #else
 709 #define NUMA_BUILD 0
 710 #endif
 711
 712 /* This helps us avoid #ifdef CONFIG_COMPACTION */
 713 #ifdef CONFIG_COMPACTION
 714 #define COMPACTION_BUILD 1
 715 #else
 716 #define COMPACTION_BUILD 0
 717 #endif
 718
 719 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 720 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 721 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 722 #endif
 723
 724 struct sysinfo;
 725 extern int do_sysinfo(struct sysinfo *info);
 726
 727 #endif /* __KERNEL__ */
 728
 729 #define SI_LOAD_SHIFT   16
 730 struct sysinfo {
 731         long uptime;                    /* Seconds since boot */
 732         unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 733         unsigned long totalram;         /* Total usable main memory size */
 734         unsigned long freeram;          /* Available memory size */
 735         unsigned long sharedram;        /* Amount of shared memory */
 736         unsigned long bufferram;        /* Memory used by buffers */
 737         unsigned long totalswap;        /* Total swap space size */
 738         unsigned long freeswap;         /* swap space still available */
 739         unsigned short procs;           /* Number of current processes */
 740         unsigned short pad;             /* explicit padding for m68k */
 741         unsigned long totalhigh;        /* Total high memory size */
 742         unsigned long freehigh;         /* Available high memory size */
 743         unsigned int mem_unit;          /* Memory unit size in bytes */
 744         char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 745 };
 746
 747 #endif