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 /*
  89  * Multiplies an integer by a fraction, while avoiding unnecessary
  90  * overflow or loss of precision.
  91  */
  92 #define mult_frac(x, numer, denom)(                     \
  93 {                                                       \
  94         typeof(x) quot = (x) / (denom);                 \
  95         typeof(x) rem  = (x) % (denom);                 \
  96         (quot * (numer)) + ((rem * (numer)) / (denom)); \
  97 }                                                       \
  98 )
  99
 100
 101 #define _RET_IP_                (unsigned long)__builtin_return_address(0)
 102 #define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
 103
 104 #ifdef CONFIG_LBDAF
 105 # include <asm/div64.h>
 106 # define sector_div(a, b) do_div(a, b)
 107 #else
 108 # define sector_div(n, b)( \
 109 { \
 110         int _res; \
 111         _res = (n) % (b); \
 112         (n) /= (b); \
 113         _res; \
 114 } \
 115 )
 116 #endif
 117
 118 /**
 119  * upper_32_bits - return bits 32-63 of a number
 120  * @n: the number we're accessing
 121  *
 122  * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
 123  * the "right shift count >= width of type" warning when that quantity is
 124  * 32-bits.
 125  */
 126 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
 127
 128 /**
 129  * lower_32_bits - return bits 0-31 of a number
 130  * @n: the number we're accessing
 131  */
 132 #define lower_32_bits(n) ((u32)(n))
 133
 134 struct completion;
 135 struct pt_regs;
 136 struct user;
 137
 138 #ifdef CONFIG_PREEMPT_VOLUNTARY
 139 extern int _cond_resched(void);
 140 # define might_resched() _cond_resched()
 141 #else
 142 # define might_resched() do { } while (0)
 143 #endif
 144
 145 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 146   void __might_sleep(const char *file, int line, int preempt_offset);
 147 /**
 148  * might_sleep - annotation for functions that can sleep
 149  *
 150  * this macro will print a stack trace if it is executed in an atomic
 151  * context (spinlock, irq-handler, ...).
 152  *
 153  * This is a useful debugging help to be able to catch problems early and not
 154  * be bitten later when the calling function happens to sleep when it is not
 155  * supposed to.
 156  */
 157 # define might_sleep() \
 158         do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 159 #else
 160   static inline void __might_sleep(const char *file, int line,
 161                                    int preempt_offset) { }
 162 # define might_sleep() do { might_resched(); } while (0)
 163 #endif
 164
 165 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 166
 167 /*
 168  * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
 169  * input types abs() returns a signed long.
 170  * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
 171  * for those.
 172  */
 173 #define abs(x) ({                                               \
 174                 long ret;                                       \
 175                 if (sizeof(x) == sizeof(long)) {                \
 176                         long __x = (x);                         \
 177                         ret = (__x < 0) ? -__x : __x;           \
 178                 } else {                                        \
 179                         int __x = (x);                          \
 180                         ret = (__x < 0) ? -__x : __x;           \
 181                 }                                               \
 182                 ret;                                            \
 183         })
 184
 185 #define abs64(x) ({                             \
 186                 s64 __x = (x);                  \
 187                 (__x < 0) ? -__x : __x;         \
 188         })
 189
 190 #ifdef CONFIG_PROVE_LOCKING
 191 void might_fault(void);
 192 #else
 193 static inline void might_fault(void)
 194 {
 195         might_sleep();
 196 }
 197 #endif
 198
 199 extern struct atomic_notifier_head panic_notifier_list;
 200 extern long (*panic_blink)(int state);
 201 __printf(1, 2)
 202 void panic(const char *fmt, ...)
 203         __noreturn __cold;
 204 extern void oops_enter(void);
 205 extern void oops_exit(void);
 206 void print_oops_end_marker(void);
 207 extern int oops_may_print(void);
 208 void do_exit(long error_code)
 209         __noreturn;
 210 void complete_and_exit(struct completion *, long)
 211         __noreturn;
 212
 213 /* Internal, do not use. */
 214 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 215 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 216
 217 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 218 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 219 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 220 {
 221         /*
 222          * We want to shortcut function call, but
 223          * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 224          */
 225         if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 226             __alignof__(unsigned long) == __alignof__(unsigned long long))
 227                 return kstrtoull(s, base, (unsigned long long *)res);
 228         else
 229                 return _kstrtoul(s, base, res);
 230 }
 231
 232 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 233 {
 234         /*
 235          * We want to shortcut function call, but
 236          * __builtin_types_compatible_p(long, long long) = 0.
 237          */
 238         if (sizeof(long) == sizeof(long long) &&
 239             __alignof__(long) == __alignof__(long long))
 240                 return kstrtoll(s, base, (long long *)res);
 241         else
 242                 return _kstrtol(s, base, res);
 243 }
 244
 245 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 246 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 247
 248 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 249 {
 250         return kstrtoull(s, base, res);
 251 }
 252
 253 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 254 {
 255         return kstrtoll(s, base, res);
 256 }
 257
 258 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 259 {
 260         return kstrtouint(s, base, res);
 261 }
 262
 263 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 264 {
 265         return kstrtoint(s, base, res);
 266 }
 267
 268 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 269 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 270 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 271 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 272
 273 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 274 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 275 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 276 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 277 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 278 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 279 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 280 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 281 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 282 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 283
 284 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 285 {
 286         return kstrtoull_from_user(s, count, base, res);
 287 }
 288
 289 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 290 {
 291         return kstrtoll_from_user(s, count, base, res);
 292 }
 293
 294 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 295 {
 296         return kstrtouint_from_user(s, count, base, res);
 297 }
 298
 299 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 300 {
 301         return kstrtoint_from_user(s, count, base, res);
 302 }
 303
 304 /* Obsolete, do not use.  Use kstrto<foo> instead */
 305
 306 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 307 extern long simple_strtol(const char *,char **,unsigned int);
 308 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 309 extern long long simple_strtoll(const char *,char **,unsigned int);
 310 #define strict_strtoul  kstrtoul
 311 #define strict_strtol   kstrtol
 312 #define strict_strtoull kstrtoull
 313 #define strict_strtoll  kstrtoll
 314
 315 /* lib/printf utilities */
 316
 317 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 318 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 319 extern __printf(3, 4)
 320 int snprintf(char *buf, size_t size, const char *fmt, ...);
 321 extern __printf(3, 0)
 322 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 323 extern __printf(3, 4)
 324 int scnprintf(char *buf, size_t size, const char *fmt, ...);
 325 extern __printf(3, 0)
 326 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 327 extern __printf(2, 3)
 328 char *kasprintf(gfp_t gfp, const char *fmt, ...);
 329 extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 330
 331 extern __scanf(2, 3)
 332 int sscanf(const char *, const char *, ...);
 333 extern __scanf(2, 0)
 334 int vsscanf(const char *, const char *, va_list);
 335
 336 extern int get_option(char **str, int *pint);
 337 extern char *get_options(const char *str, int nints, int *ints);
 338 extern unsigned long long memparse(const char *ptr, char **retptr);
 339
 340 extern int core_kernel_text(unsigned long addr);
 341 extern int core_kernel_data(unsigned long addr);
 342 extern int __kernel_text_address(unsigned long addr);
 343 extern int kernel_text_address(unsigned long addr);
 344 extern int func_ptr_is_kernel_text(void *ptr);
 345
 346 struct pid;
 347 extern struct pid *session_of_pgrp(struct pid *pgrp);
 348
 349 unsigned long int_sqrt(unsigned long);
 350
 351 extern void bust_spinlocks(int yes);
 352 extern void wake_up_klogd(void);
 353 extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 354 extern int panic_timeout;
 355 extern int panic_on_oops;
 356 extern int panic_on_unrecovered_nmi;
 357 extern int panic_on_io_nmi;
 358 extern int sysctl_panic_on_stackoverflow;
 359 extern const char *print_tainted(void);
 360 extern void add_taint(unsigned flag);
 361 extern int test_taint(unsigned flag);
 362 extern unsigned long get_taint(void);
 363 extern int root_mountflags;
 364
 365 extern bool early_boot_irqs_disabled;
 366
 367 /* Values used for system_state */
 368 extern enum system_states {
 369         SYSTEM_BOOTING,
 370         SYSTEM_RUNNING,
 371         SYSTEM_HALT,
 372         SYSTEM_POWER_OFF,
 373         SYSTEM_RESTART,
 374         SYSTEM_SUSPEND_DISK,
 375 } system_state;
 376
 377 #define TAINT_PROPRIETARY_MODULE        0
 378 #define TAINT_FORCED_MODULE             1
 379 #define TAINT_UNSAFE_SMP                2
 380 #define TAINT_FORCED_RMMOD              3
 381 #define TAINT_MACHINE_CHECK             4
 382 #define TAINT_BAD_PAGE                  5
 383 #define TAINT_USER                      6
 384 #define TAINT_DIE                       7
 385 #define TAINT_OVERRIDDEN_ACPI_TABLE     8
 386 #define TAINT_WARN                      9
 387 #define TAINT_CRAP                      10
 388 #define TAINT_FIRMWARE_WORKAROUND       11
 389 #define TAINT_OOT_MODULE                12
 390
 391 extern const char hex_asc[];
 392 #define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 393 #define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 394
 395 static inline char *hex_byte_pack(char *buf, u8 byte)
 396 {
 397         *buf++ = hex_asc_hi(byte);
 398         *buf++ = hex_asc_lo(byte);
 399         return buf;
 400 }
 401
 402 static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 403 {
 404         return hex_byte_pack(buf, byte);
 405 }
 406
 407 extern int hex_to_bin(char ch);
 408 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 409
 410 /*
 411  * General tracing related utility functions - trace_printk(),
 412  * tracing_on/tracing_off and tracing_start()/tracing_stop
 413  *
 414  * Use tracing_on/tracing_off when you want to quickly turn on or off
 415  * tracing. It simply enables or disables the recording of the trace events.
 416  * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 417  * file, which gives a means for the kernel and userspace to interact.
 418  * Place a tracing_off() in the kernel where you want tracing to end.
 419  * From user space, examine the trace, and then echo 1 > tracing_on
 420  * to continue tracing.
 421  *
 422  * tracing_stop/tracing_start has slightly more overhead. It is used
 423  * by things like suspend to ram where disabling the recording of the
 424  * trace is not enough, but tracing must actually stop because things
 425  * like calling smp_processor_id() may crash the system.
 426  *
 427  * Most likely, you want to use tracing_on/tracing_off.
 428  */
 429 #ifdef CONFIG_RING_BUFFER
 430 void tracing_on(void);
 431 void tracing_off(void);
 432 /* trace_off_permanent stops recording with no way to bring it back */
 433 void tracing_off_permanent(void);
 434 int tracing_is_on(void);
 435 #else
 436 static inline void tracing_on(void) { }
 437 static inline void tracing_off(void) { }
 438 static inline void tracing_off_permanent(void) { }
 439 static inline int tracing_is_on(void) { return 0; }
 440 #endif
 441
 442 enum ftrace_dump_mode {
 443         DUMP_NONE,
 444         DUMP_ALL,
 445         DUMP_ORIG,
 446 };
 447
 448 #ifdef CONFIG_TRACING
 449 extern void tracing_start(void);
 450 extern void tracing_stop(void);
 451 extern void ftrace_off_permanent(void);
 452
 453 static inline __printf(1, 2)
 454 void ____trace_printk_check_format(const char *fmt, ...)
 455 {
 456 }
 457 #define __trace_printk_check_format(fmt, args...)                       \
 458 do {                                                                    \
 459         if (0)                                                          \
 460                 ____trace_printk_check_format(fmt, ##args);             \
 461 } while (0)
 462
 463 /**
 464  * trace_printk - printf formatting in the ftrace buffer
 465  * @fmt: the printf format for printing
 466  *
 467  * Note: __trace_printk is an internal function for trace_printk and
 468  *       the @ip is passed in via the trace_printk macro.
 469  *
 470  * This function allows a kernel developer to debug fast path sections
 471  * that printk is not appropriate for. By scattering in various
 472  * printk like tracing in the code, a developer can quickly see
 473  * where problems are occurring.
 474  *
 475  * This is intended as a debugging tool for the developer only.
 476  * Please refrain from leaving trace_printks scattered around in
 477  * your code.
 478  */
 479
 480 #define trace_printk(fmt, args...)                                      \
 481 do {                                                                    \
 482         __trace_printk_check_format(fmt, ##args);                       \
 483         if (__builtin_constant_p(fmt)) {                                \
 484                 static const char *trace_printk_fmt                     \
 485                   __attribute__((section("__trace_printk_fmt"))) =      \
 486                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 487                                                                         \
 488                 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 489         } else                                                          \
 490                 __trace_printk(_THIS_IP_, fmt, ##args);         \
 491 } while (0)
 492
 493 extern __printf(2, 3)
 494 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 495
 496 extern __printf(2, 3)
 497 int __trace_printk(unsigned long ip, const char *fmt, ...);
 498
 499 extern void trace_dump_stack(void);
 500
 501 /*
 502  * The double __builtin_constant_p is because gcc will give us an error
 503  * if we try to allocate the static variable to fmt if it is not a
 504  * constant. Even with the outer if statement.
 505  */
 506 #define ftrace_vprintk(fmt, vargs)                                      \
 507 do {                                                                    \
 508         if (__builtin_constant_p(fmt)) {                                \
 509                 static const char *trace_printk_fmt                     \
 510                   __attribute__((section("__trace_printk_fmt"))) =      \
 511                         __builtin_constant_p(fmt) ? fmt : NULL;         \
 512                                                                         \
 513                 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 514         } else                                                          \
 515                 __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 516 } while (0)
 517
 518 extern int
 519 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 520
 521 extern int
 522 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 523
 524 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 525 #else
 526 static inline __printf(1, 2)
 527 int trace_printk(const char *fmt, ...);
 528
 529 static inline void tracing_start(void) { }
 530 static inline void tracing_stop(void) { }
 531 static inline void ftrace_off_permanent(void) { }
 532 static inline void trace_dump_stack(void) { }
 533 static inline int
 534 trace_printk(const char *fmt, ...)
 535 {
 536         return 0;
 537 }
 538 static inline int
 539 ftrace_vprintk(const char *fmt, va_list ap)
 540 {
 541         return 0;
 542 }
 543 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 544 #endif /* CONFIG_TRACING */
 545
 546 /*
 547  * min()/max()/clamp() macros that also do
 548  * strict type-checking.. See the
 549  * "unnecessary" pointer comparison.
 550  */
 551 #define min(x, y) ({                            \
 552         typeof(x) _min1 = (x);                  \
 553         typeof(y) _min2 = (y);                  \
 554         (void) (&_min1 == &_min2);              \
 555         _min1 < _min2 ? _min1 : _min2; })
 556
 557 #define max(x, y) ({                            \
 558         typeof(x) _max1 = (x);                  \
 559         typeof(y) _max2 = (y);                  \
 560         (void) (&_max1 == &_max2);              \
 561         _max1 > _max2 ? _max1 : _max2; })
 562
 563 #define min3(x, y, z) ({                        \
 564         typeof(x) _min1 = (x);                  \
 565         typeof(y) _min2 = (y);                  \
 566         typeof(z) _min3 = (z);                  \
 567         (void) (&_min1 == &_min2);              \
 568         (void) (&_min1 == &_min3);              \
 569         _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 570                 (_min2 < _min3 ? _min2 : _min3); })
 571
 572 #define max3(x, y, z) ({                        \
 573         typeof(x) _max1 = (x);                  \
 574         typeof(y) _max2 = (y);                  \
 575         typeof(z) _max3 = (z);                  \
 576         (void) (&_max1 == &_max2);              \
 577         (void) (&_max1 == &_max3);              \
 578         _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 579                 (_max2 > _max3 ? _max2 : _max3); })
 580
 581 /**
 582  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 583  * @x: value1
 584  * @y: value2
 585  */
 586 #define min_not_zero(x, y) ({                   \
 587         typeof(x) __x = (x);                    \
 588         typeof(y) __y = (y);                    \
 589         __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 590
 591 /**
 592  * clamp - return a value clamped to a given range with strict typechecking
 593  * @val: current value
 594  * @min: minimum allowable value
 595  * @max: maximum allowable value
 596  *
 597  * This macro does strict typechecking of min/max to make sure they are of the
 598  * same type as val.  See the unnecessary pointer comparisons.
 599  */
 600 #define clamp(val, min, max) ({                 \
 601         typeof(val) __val = (val);              \
 602         typeof(min) __min = (min);              \
 603         typeof(max) __max = (max);              \
 604         (void) (&__val == &__min);              \
 605         (void) (&__val == &__max);              \
 606         __val = __val < __min ? __min: __val;   \
 607         __val > __max ? __max: __val; })
 608
 609 /*
 610  * ..and if you can't take the strict
 611  * types, you can specify one yourself.
 612  *
 613  * Or not use min/max/clamp at all, of course.
 614  */
 615 #define min_t(type, x, y) ({                    \
 616         type __min1 = (x);                      \
 617         type __min2 = (y);                      \
 618         __min1 < __min2 ? __min1: __min2; })
 619
 620 #define max_t(type, x, y) ({                    \
 621         type __max1 = (x);                      \
 622         type __max2 = (y);                      \
 623         __max1 > __max2 ? __max1: __max2; })
 624
 625 /**
 626  * clamp_t - return a value clamped to a given range using a given type
 627  * @type: the type of variable to use
 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 type
 633  * 'type' to make all the comparisons.
 634  */
 635 #define clamp_t(type, val, min, max) ({         \
 636         type __val = (val);                     \
 637         type __min = (min);                     \
 638         type __max = (max);                     \
 639         __val = __val < __min ? __min: __val;   \
 640         __val > __max ? __max: __val; })
 641
 642 /**
 643  * clamp_val - return a value clamped to a given range using val's type
 644  * @val: current value
 645  * @min: minimum allowable value
 646  * @max: maximum allowable value
 647  *
 648  * This macro does no typechecking and uses temporary variables of whatever
 649  * type the input argument 'val' is.  This is useful when val is an unsigned
 650  * type and min and max are literals that will otherwise be assigned a signed
 651  * integer type.
 652  */
 653 #define clamp_val(val, min, max) ({             \
 654         typeof(val) __val = (val);              \
 655         typeof(val) __min = (min);              \
 656         typeof(val) __max = (max);              \
 657         __val = __val < __min ? __min: __val;   \
 658         __val > __max ? __max: __val; })
 659
 660
 661 /*
 662  * swap - swap value of @a and @b
 663  */
 664 #define swap(a, b) \
 665         do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 666
 667 /**
 668  * container_of - cast a member of a structure out to the containing structure
 669  * @ptr:        the pointer to the member.
 670  * @type:       the type of the container struct this is embedded in.
 671  * @member:     the name of the member within the struct.
 672  *
 673  */
 674 #define container_of(ptr, type, member) ({                      \
 675         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 676         (type *)( (char *)__mptr - offsetof(type,member) );})
 677
 678 #ifdef __CHECKER__
 679 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)
 680 #define BUILD_BUG_ON_ZERO(e) (0)
 681 #define BUILD_BUG_ON_NULL(e) ((void*)0)
 682 #define BUILD_BUG_ON(condition)
 683 #define BUILD_BUG() (0)
 684 #else /* __CHECKER__ */
 685
 686 /* Force a compilation error if a constant expression is not a power of 2 */
 687 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
 688         BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
 689
 690 /* Force a compilation error if condition is true, but also produce a
 691    result (of value 0 and type size_t), so the expression can be used
 692    e.g. in a structure initializer (or where-ever else comma expressions
 693    aren't permitted). */
 694 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 695 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
 696
 697 /**
 698  * BUILD_BUG_ON - break compile if a condition is true.
 699  * @condition: the condition which the compiler should know is false.
 700  *
 701  * If you have some code which relies on certain constants being equal, or
 702  * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 703  * detect if someone changes it.
 704  *
 705  * The implementation uses gcc's reluctance to create a negative array, but
 706  * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 707  * to inline functions).  So as a fallback we use the optimizer; if it can't
 708  * prove the condition is false, it will cause a link error on the undefined
 709  * "__build_bug_on_failed".  This error message can be harder to track down
 710  * though, hence the two different methods.
 711  */
 712 #ifndef __OPTIMIZE__
 713 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 714 #else
 715 extern int __build_bug_on_failed;
 716 #define BUILD_BUG_ON(condition)                                 \
 717         do {                                                    \
 718                 ((void)sizeof(char[1 - 2*!!(condition)]));      \
 719                 if (condition) __build_bug_on_failed = 1;       \
 720         } while(0)
 721 #endif
 722
 723 /**
 724  * BUILD_BUG - break compile if used.
 725  *
 726  * If you have some code that you expect the compiler to eliminate at
 727  * build time, you should use BUILD_BUG to detect if it is
 728  * unexpectedly used.
 729  */
 730 #define BUILD_BUG()                                             \
 731         do {                                                    \
 732                 extern void __build_bug_failed(void)            \
 733                         __linktime_error("BUILD_BUG failed");   \
 734                 __build_bug_failed();                           \
 735         } while (0)
 736
 737 #endif  /* __CHECKER__ */
 738
 739 /* Trap pasters of __FUNCTION__ at compile-time */
 740 #define __FUNCTION__ (__func__)
 741
 742 /* This helps us to avoid #ifdef CONFIG_NUMA */
 743 #ifdef CONFIG_NUMA
 744 #define NUMA_BUILD 1
 745 #else
 746 #define NUMA_BUILD 0
 747 #endif
 748
 749 /* This helps us avoid #ifdef CONFIG_COMPACTION */
 750 #ifdef CONFIG_COMPACTION
 751 #define COMPACTION_BUILD 1
 752 #else
 753 #define COMPACTION_BUILD 0
 754 #endif
 755
 756 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 757 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 758 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 759 #endif
 760
 761 struct sysinfo;
 762 extern int do_sysinfo(struct sysinfo *info);
 763
 764 #endif /* __KERNEL__ */
 765
 766 #define SI_LOAD_SHIFT   16
 767 struct sysinfo {
 768         long uptime;                    /* Seconds since boot */
 769         unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 770         unsigned long totalram;         /* Total usable main memory size */
 771         unsigned long freeram;          /* Available memory size */
 772         unsigned long sharedram;        /* Amount of shared memory */
 773         unsigned long bufferram;        /* Memory used by buffers */
 774         unsigned long totalswap;        /* Total swap space size */
 775         unsigned long freeswap;         /* swap space still available */
 776         unsigned short procs;           /* Number of current processes */
 777         unsigned short pad;             /* explicit padding for m68k */
 778         unsigned long totalhigh;        /* Total high memory size */
 779         unsigned long freehigh;         /* Available high memory size */
 780         unsigned int mem_unit;          /* Memory unit size in bytes */
 781         char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 782 };
 783
 784 #endif