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