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 int sysctl_panic_on_stackoverflow;
 345 extern const char *print_tainted(void);
 346 extern void add_taint(unsigned flag);
 347 extern int test_taint(unsigned flag);
 348 extern unsigned long get_taint(void);
 349 extern int root_mountflags;
 350
 351 extern bool early_boot_irqs_disabled;
 352
 353 /* Values used for system_state */
 354 extern enum system_states {
 355         SYSTEM_BOOTING,
 356         SYSTEM_RUNNING,
 357         SYSTEM_HALT,
 358         SYSTEM_POWER_OFF,
 359         SYSTEM_RESTART,
 360         SYSTEM_SUSPEND_DISK,
 361 } system_state;
 362
 363 #define TAINT_PROPRIETARY_MODULE        0
 364 #define TAINT_FORCED_MODULE             1
 365 #define TAINT_UNSAFE_SMP                2
 366 #define TAINT_FORCED_RMMOD              3
 367 #define TAINT_MACHINE_CHECK             4
 368 #define TAINT_BAD_PAGE                  5
 369 #define TAINT_USER                      6
 370 #define TAINT_DIE                       7
 371 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
 372 #define TAINT_WARN                      9
 373 #define TAINT_CRAP                      10
 374 #define TAINT_FIRMWARE_WORKAROUND       11
 375 #define TAINT_OOT_MODULE                12
 376
 377 extern const char hex_asc[];
 378 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 379 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 380
 381 static inline char *hex_byte_pack(char *buf, u8 byte)
 382 {
 383         *buf++ = hex_asc_hi(byte);
 384         *buf++ = hex_asc_lo(byte);
 385         return buf;
 386 }
 387
 388 static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 389 {
 390         return hex_byte_pack(buf, byte);
 391 }
 392
 393 extern int hex_to_bin(char ch);
 394 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 395
 396 /*
 397  * General tracing related utility functions - trace_printk(),
 398  * tracing_on/tracing_off and tracing_start()/tracing_stop
 399  *
 400  * Use tracing_on/tracing_off when you want to quickly turn on or off
 401  * tracing. It simply enables or disables the recording of the trace events.
 402  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 403  * file, which gives a means for the kernel and userspace to interact.
 404  * Place a tracing_off() in the kernel where you want tracing to end.
 405  * From user space, examine the trace, and then echo 1 > tracing_on
 406  * to continue tracing.
 407  *
 408  * tracing_stop/tracing_start has slightly more overhead. It is used
 409  * by things like suspend to ram where disabling the recording of the
 410  * trace is not enough, but tracing must actually stop because things
 411  * like calling smp_processor_id() may crash the system.
 412  *
 413  * Most likely, you want to use tracing_on/tracing_off.
 414  */
 415 #ifdef CONFIG_RING_BUFFER
 416 void tracing_on(void);
 417 void tracing_off(void);
 418 /* trace_off_permanent stops recording with no way to bring it back */
 419 void tracing_off_permanent(void);
 420 int tracing_is_on(void);
 421 #else
 422 static inline void tracing_on(void) { }
 423 static inline void tracing_off(void) { }
 424 static inline void tracing_off_permanent(void) { }
 425 static inline int tracing_is_on(void) { return 0; }
 426 #endif
 427
 428 enum ftrace_dump_mode {
 429         DUMP_NONE,
 430         DUMP_ALL,
 431         DUMP_ORIG,
 432 };
 433
 434 #ifdef CONFIG_TRACING
 435 extern void tracing_start(void);
 436 extern void tracing_stop(void);
 437 extern void ftrace_off_permanent(void);
 438
 439 static inline __printf(1, 2)
 440 void ____trace_printk_check_format(const char *fmt, ...)
 441 {
 442 }
 443 #define __trace_printk_check_format(fmt, args...)                       \
 444 do {                                                                    \
 445         if (0)                                                          \
 446                 ____trace_printk_check_format(fmt, ##args);             \
 447 } while (0)
 448
 449 /**
 450  * trace_printk - printf formatting in the ftrace buffer
 451  * @fmt: the printf format for printing
 452  *
 453  * Note: __trace_printk is an internal function for trace_printk and
 454  *       the @ip is passed in via the trace_printk macro.
 455  *
 456  * This function allows a kernel developer to debug fast path sections
 457  * that printk is not appropriate for. By scattering in various
 458  * printk like tracing in the code, a developer can quickly see
 459  * where problems are occurring.
 460  *
 461  * This is intended as a debugging tool for the developer only.
 462  * Please refrain from leaving trace_printks scattered around in
 463  * your code.
 464  */
 465
 466 #define trace_printk(fmt, args...)                                      \
 467 do {                                                                    \
 468         __trace_printk_check_format(fmt, ##args);                       \
 469         if (__builtin_constant_p(fmt)) {                                \
 470                 static const char *trace_printk_fmt                     \
 471                   __attribute__((section("__trace_printk_fmt"))) =      \
 472                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 473                                                                         \
 474                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 475         } else                                                          \
 476                 __trace_printk(_THIS_IP_, fmt, ##args);         \
 477 } while (0)
 478
 479 extern __printf(2, 3)
 480 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 481
 482 extern __printf(2, 3)
 483 int __trace_printk(unsigned long ip, const char *fmt, ...);
 484
 485 extern void trace_dump_stack(void);
 486
 487 /*
 488  * The double __builtin_constant_p is because gcc will give us an error
 489  * if we try to allocate the static variable to fmt if it is not a
 490  * constant. Even with the outer if statement.
 491  */
 492 #define ftrace_vprintk(fmt, vargs)                                      \
 493 do {                                                                    \
 494         if (__builtin_constant_p(fmt)) {                                \
 495                 static const char *trace_printk_fmt                     \
 496                   __attribute__((section("__trace_printk_fmt"))) =      \
 497                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 498                                                                         \
 499                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 500         } else                                                          \
 501                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 502 } while (0)
 503
 504 extern int
 505 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 506
 507 extern int
 508 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 509
 510 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 511 #else
 512 static inline __printf(1, 2)
 513 int trace_printk(const char *fmt, ...);
 514
 515 static inline void tracing_start(void) { }
 516 static inline void tracing_stop(void) { }
 517 static inline void ftrace_off_permanent(void) { }
 518 static inline void trace_dump_stack(void) { }
 519 static inline int
 520 trace_printk(const char *fmt, ...)
 521 {
 522         return 0;
 523 }
 524 static inline int
 525 ftrace_vprintk(const char *fmt, va_list ap)
 526 {
 527         return 0;
 528 }
 529 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 530 #endif /* CONFIG_TRACING */
 531
 532 /*
 533  * min()/max()/clamp() macros that also do
 534  * strict type-checking.. See the
 535  * "unnecessary" pointer comparison.
 536  */
 537 #define min(x, y) ({                            \
 538         typeof(x) _min1 = (x);                  \
 539         typeof(y) _min2 = (y);                  \
 540         (void) (&_min1 == &_min2);              \
 541         _min1 < _min2 ? _min1 : _min2; })
 542
 543 #define max(x, y) ({                            \
 544         typeof(x) _max1 = (x);                  \
 545         typeof(y) _max2 = (y);                  \
 546         (void) (&_max1 == &_max2);              \
 547         _max1 > _max2 ? _max1 : _max2; })
 548
 549 #define min3(x, y, z) ({                        \
 550         typeof(x) _min1 = (x);                  \
 551         typeof(y) _min2 = (y);                  \
 552         typeof(z) _min3 = (z);                  \
 553         (void) (&_min1 == &_min2);              \
 554         (void) (&_min1 == &_min3);              \
 555         _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 556                 (_min2 < _min3 ? _min2 : _min3); })
 557
 558 #define max3(x, y, z) ({                        \
 559         typeof(x) _max1 = (x);                  \
 560         typeof(y) _max2 = (y);                  \
 561         typeof(z) _max3 = (z);                  \
 562         (void) (&_max1 == &_max2);              \
 563         (void) (&_max1 == &_max3);              \
 564         _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 565                 (_max2 > _max3 ? _max2 : _max3); })
 566
 567 /**
 568  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 569  * @x: value1
 570  * @y: value2
 571  */
 572 #define min_not_zero(x, y) ({                   \
 573         typeof(x) __x = (x);                    \
 574         typeof(y) __y = (y);                    \
 575         __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 576
 577 /**
 578  * clamp - return a value clamped to a given range with strict typechecking
 579  * @val: current value
 580  * @min: minimum allowable value
 581  * @max: maximum allowable value
 582  *
 583  * This macro does strict typechecking of min/max to make sure they are of the
 584  * same type as val.  See the unnecessary pointer comparisons.
 585  */
 586 #define clamp(val, min, max) ({                 \
 587         typeof(val) __val = (val);              \
 588         typeof(min) __min = (min);              \
 589         typeof(max) __max = (max);              \
 590         (void) (&__val == &__min);              \
 591         (void) (&__val == &__max);              \
 592         __val = __val < __min ? __min: __val;   \
 593         __val > __max ? __max: __val; })
 594
 595 /*
 596  * ..and if you can't take the strict
 597  * types, you can specify one yourself.
 598  *
 599  * Or not use min/max/clamp at all, of course.
 600  */
 601 #define min_t(type, x, y) ({                    \
 602         type __min1 = (x);                      \
 603         type __min2 = (y);                      \
 604         __min1 < __min2 ? __min1: __min2; })
 605
 606 #define max_t(type, x, y) ({                    \
 607         type __max1 = (x);                      \
 608         type __max2 = (y);                      \
 609         __max1 > __max2 ? __max1: __max2; })
 610
 611 /**
 612  * clamp_t - return a value clamped to a given range using a given type
 613  * @type: the type of variable to use
 614  * @val: current value
 615  * @min: minimum allowable value
 616  * @max: maximum allowable value
 617  *
 618  * This macro does no typechecking and uses temporary variables of type
 619  * 'type' to make all the comparisons.
 620  */
 621 #define clamp_t(type, val, min, max) ({         \
 622         type __val = (val);                     \
 623         type __min = (min);                     \
 624         type __max = (max);                     \
 625         __val = __val < __min ? __min: __val;   \
 626         __val > __max ? __max: __val; })
 627
 628 /**
 629  * clamp_val - return a value clamped to a given range using val's type
 630  * @val: current value
 631  * @min: minimum allowable value
 632  * @max: maximum allowable value
 633  *
 634  * This macro does no typechecking and uses temporary variables of whatever
 635  * type the input argument 'val' is.  This is useful when val is an unsigned
 636  * type and min and max are literals that will otherwise be assigned a signed
 637  * integer type.
 638  */
 639 #define clamp_val(val, min, max) ({             \
 640         typeof(val) __val = (val);              \
 641         typeof(val) __min = (min);              \
 642         typeof(val) __max = (max);              \
 643         __val = __val < __min ? __min: __val;   \
 644         __val > __max ? __max: __val; })
 645
 646
 647 /*
 648  * swap - swap value of @a and @b
 649  */
 650 #define swap(a, b) \
 651         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 652
 653 /**
 654  * container_of - cast a member of a structure out to the containing structure
 655  * @ptr:        the pointer to the member.
 656  * @type:       the type of the container struct this is embedded in.
 657  * @member:     the name of the member within the struct.
 658  *
 659  */
 660 #define container_of(ptr, type, member) ({                      \
 661         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 662         (type *)( (char *)__mptr - offsetof(type,member) );})
 663
 664 #ifdef __CHECKER__
 665 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)
 666 #define BUILD_BUG_ON_ZERO(e) (0)
 667 #define BUILD_BUG_ON_NULL(e) ((void*)0)
 668 #define BUILD_BUG_ON(condition)
 669 #else /* __CHECKER__ */
 670
 671 /* Force a compilation error if a constant expression is not a power of 2 */
 672 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
 673         BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
 674
 675 /* Force a compilation error if condition is true, but also produce a
 676    result (of value 0 and type size_t), so the expression can be used
 677    e.g. in a structure initializer (or where-ever else comma expressions
 678    aren't permitted). */
 679 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 680 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
 681
 682 /**
 683  * BUILD_BUG_ON - break compile if a condition is true.
 684  * @condition: the condition which the compiler should know is false.
 685  *
 686  * If you have some code which relies on certain constants being equal, or
 687  * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 688  * detect if someone changes it.
 689  *
 690  * The implementation uses gcc's reluctance to create a negative array, but
 691  * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 692  * to inline functions).  So as a fallback we use the optimizer; if it can't
 693  * prove the condition is false, it will cause a link error on the undefined
 694  * "__build_bug_on_failed".  This error message can be harder to track down
 695  * though, hence the two different methods.
 696  */
 697 #ifndef __OPTIMIZE__
 698 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 699 #else
 700 extern int __build_bug_on_failed;
 701 #define BUILD_BUG_ON(condition)                                 \
 702         do {                                                    \
 703                 ((void)sizeof(char[1 - 2*!!(condition)]));      \
 704                 if (condition) __build_bug_on_failed = 1;       \
 705         } while(0)
 706 #endif
 707 #endif  /* __CHECKER__ */
 708
 709 /* Trap pasters of __FUNCTION__ at compile-time */
 710 #define __FUNCTION__ (__func__)
 711
 712 /* This helps us to avoid #ifdef CONFIG_NUMA */
 713 #ifdef CONFIG_NUMA
 714 #define NUMA_BUILD 1
 715 #else
 716 #define NUMA_BUILD 0
 717 #endif
 718
 719 /* This helps us avoid #ifdef CONFIG_COMPACTION */
 720 #ifdef CONFIG_COMPACTION
 721 #define COMPACTION_BUILD 1
 722 #else
 723 #define COMPACTION_BUILD 0
 724 #endif
 725
 726 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 727 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 728 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 729 #endif
 730
 731 struct sysinfo;
 732 extern int do_sysinfo(struct sysinfo *info);
 733
 734 #endif /* __KERNEL__ */
 735
 736 #define SI_LOAD_SHIFT   16
 737 struct sysinfo {
 738         long uptime;                    /* Seconds since boot */
 739         unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 740         unsigned long totalram;         /* Total usable main memory size */
 741         unsigned long freeram;          /* Available memory size */
 742         unsigned long sharedram;        /* Amount of shared memory */
 743         unsigned long bufferram;        /* Memory used by buffers */
 744         unsigned long totalswap;        /* Total swap space size */
 745         unsigned long freeswap;         /* swap space still available */
 746         unsigned short procs;           /* Number of current processes */
 747         unsigned short pad;             /* explicit padding for m68k */
 748         unsigned long totalhigh;        /* Total high memory size */
 749         unsigned long freehigh;         /* Available high memory size */
 750         unsigned int mem_unit;          /* Memory unit size in bytes */
 751         char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 752 };
 753
 754 #endif