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