linux/include/linux/kernel.h
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   1#ifndef _LINUX_KERNEL_H
   2#define _LINUX_KERNEL_H
   3
   4/*
   5 * 'kernel.h' contains some often-used function prototypes etc
   6 */
   7#define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
   8#define __ALIGN_KERNEL_MASK(x, mask)    (((x) + (mask)) & ~(mask))
   9
  10#ifdef __KERNEL__
  11
  12#include <stdarg.h>
  13#include <linux/linkage.h>
  14#include <linux/stddef.h>
  15#include <linux/types.h>
  16#include <linux/compiler.h>
  17#include <linux/bitops.h>
  18#include <linux/log2.h>
  19#include <linux/typecheck.h>
  20#include <linux/printk.h>
  21#include <linux/dynamic_debug.h>
  22#include <asm/byteorder.h>
  23#include <asm/bug.h>
  24
  25#define USHRT_MAX       ((u16)(~0U))
  26#define SHRT_MAX        ((s16)(USHRT_MAX>>1))
  27#define SHRT_MIN        ((s16)(-SHRT_MAX - 1))
  28#define INT_MAX         ((int)(~0U>>1))
  29#define INT_MIN         (-INT_MAX - 1)
  30#define UINT_MAX        (~0U)
  31#define LONG_MAX        ((long)(~0UL>>1))
  32#define LONG_MIN        (-LONG_MAX - 1)
  33#define ULONG_MAX       (~0UL)
  34#define LLONG_MAX       ((long long)(~0ULL>>1))
  35#define LLONG_MIN       (-LLONG_MAX - 1)
  36#define ULLONG_MAX      (~0ULL)
  37
  38#define STACK_MAGIC     0xdeadbeef
  39
  40#define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
  41#define __ALIGN_MASK(x, mask)   __ALIGN_KERNEL_MASK((x), (mask))
  42#define PTR_ALIGN(p, a)         ((typeof(p))ALIGN((unsigned long)(p), (a)))
  43#define IS_ALIGNED(x, a)                (((x) & ((typeof(x))(a) - 1)) == 0)
  44
  45#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  46
  47/*
  48 * This looks more complex than it should be. But we need to
  49 * get the type for the ~ right in round_down (it needs to be
  50 * as wide as the result!), and we want to evaluate the macro
  51 * arguments just once each.
  52 */
  53#define __round_mask(x, y) ((__typeof__(x))((y)-1))
  54#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
  55#define round_down(x, y) ((x) & ~__round_mask(x, y))
  56
  57#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  58#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  59#define DIV_ROUND_UP_ULL(ll,d) \
  60        ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
  61
  62#if BITS_PER_LONG == 32
  63# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
  64#else
  65# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
  66#endif
  67
  68/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
  69#define roundup(x, y) (                                 \
  70{                                                       \
  71        const typeof(y) __y = y;                        \
  72        (((x) + (__y - 1)) / __y) * __y;                \
  73}                                                       \
  74)
  75#define rounddown(x, y) (                               \
  76{                                                       \
  77        typeof(x) __x = (x);                            \
  78        __x - (__x % (y));                              \
  79}                                                       \
  80)
  81#define DIV_ROUND_CLOSEST(x, divisor)(                  \
  82{                                                       \
  83        typeof(divisor) __divisor = divisor;            \
  84        (((x) + ((__divisor) / 2)) / (__divisor));      \
  85}                                                       \
  86)
  87
  88#define _RET_IP_                (unsigned long)__builtin_return_address(0)
  89#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
  90
  91#ifdef CONFIG_LBDAF
  92# include <asm/div64.h>
  93# define sector_div(a, b) do_div(a, b)
  94#else
  95# define sector_div(n, b)( \
  96{ \
  97        int _res; \
  98        _res = (n) % (b); \
  99        (n) /= (b); \
 100        _res; \
 101} \
 102)
 103#endif
 104
 105/**
 106 * upper_32_bits - return bits 32-63 of a number
 107 * @n: the number we're accessing
 108 *
 109 * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
 110 * the "right shift count >= width of type" warning when that quantity is
 111 * 32-bits.
 112 */
 113#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
 114
 115/**
 116 * lower_32_bits - return bits 0-31 of a number
 117 * @n: the number we're accessing
 118 */
 119#define lower_32_bits(n) ((u32)(n))
 120
 121struct completion;
 122struct pt_regs;
 123struct user;
 124
 125#ifdef CONFIG_PREEMPT_VOLUNTARY
 126extern int _cond_resched(void);
 127# define might_resched() _cond_resched()
 128#else
 129# define might_resched() do { } while (0)
 130#endif
 131
 132#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 133  void __might_sleep(const char *file, int line, int preempt_offset);
 134/**
 135 * might_sleep - annotation for functions that can sleep
 136 *
 137 * this macro will print a stack trace if it is executed in an atomic
 138 * context (spinlock, irq-handler, ...).
 139 *
 140 * This is a useful debugging help to be able to catch problems early and not
 141 * be bitten later when the calling function happens to sleep when it is not
 142 * supposed to.
 143 */
 144# define might_sleep() \
 145        do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 146#else
 147  static inline void __might_sleep(const char *file, int line,
 148                                   int preempt_offset) { }
 149# define might_sleep() do { might_resched(); } while (0)
 150#endif
 151
 152#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 153
 154/*
 155 * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
 156 * input types abs() returns a signed long.
 157 * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
 158 * for those.
 159 */
 160#define abs(x) ({                                               \
 161                long ret;                                       \
 162                if (sizeof(x) == sizeof(long)) {                \
 163                        long __x = (x);                         \
 164                        ret = (__x < 0) ? -__x : __x;           \
 165                } else {                                        \
 166                        int __x = (x);                          \
 167                        ret = (__x < 0) ? -__x : __x;           \
 168                }                                               \
 169                ret;                                            \
 170        })
 171
 172#define abs64(x) ({                             \
 173                s64 __x = (x);                  \
 174                (__x < 0) ? -__x : __x;         \
 175        })
 176
 177#ifdef CONFIG_PROVE_LOCKING
 178void might_fault(void);
 179#else
 180static inline void might_fault(void)
 181{
 182        might_sleep();
 183}
 184#endif
 185
 186extern struct atomic_notifier_head panic_notifier_list;
 187extern long (*panic_blink)(int state);
 188__printf(1, 2)
 189void panic(const char *fmt, ...)
 190        __noreturn __cold;
 191extern void oops_enter(void);
 192extern void oops_exit(void);
 193void print_oops_end_marker(void);
 194extern int oops_may_print(void);
 195void do_exit(long error_code)
 196        __noreturn;
 197void complete_and_exit(struct completion *, long)
 198        __noreturn;
 199
 200/* Internal, do not use. */
 201int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 202int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 203
 204int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 205int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 206static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 207{
 208        /*
 209         * We want to shortcut function call, but
 210         * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 211         */
 212        if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 213            __alignof__(unsigned long) == __alignof__(unsigned long long))
 214                return kstrtoull(s, base, (unsigned long long *)res);
 215        else
 216                return _kstrtoul(s, base, res);
 217}
 218
 219static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 220{
 221        /*
 222         * We want to shortcut function call, but
 223         * __builtin_types_compatible_p(long, long long) = 0.
 224         */
 225        if (sizeof(long) == sizeof(long long) &&
 226            __alignof__(long) == __alignof__(long long))
 227                return kstrtoll(s, base, (long long *)res);
 228        else
 229                return _kstrtol(s, base, res);
 230}
 231
 232int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 233int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 234
 235static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 236{
 237        return kstrtoull(s, base, res);
 238}
 239
 240static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 241{
 242        return kstrtoll(s, base, res);
 243}
 244
 245static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 246{
 247        return kstrtouint(s, base, res);
 248}
 249
 250static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 251{
 252        return kstrtoint(s, base, res);
 253}
 254
 255int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 256int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 257int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 258int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 259
 260int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 261int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 262int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 263int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 264int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 265int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 266int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 267int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 268int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 269int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 270
 271static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 272{
 273        return kstrtoull_from_user(s, count, base, res);
 274}
 275
 276static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 277{
 278        return kstrtoll_from_user(s, count, base, res);
 279}
 280
 281static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 282{
 283        return kstrtouint_from_user(s, count, base, res);
 284}
 285
 286static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 287{
 288        return kstrtoint_from_user(s, count, base, res);
 289}
 290
 291/* Obsolete, do not use.  Use kstrto<foo> instead */
 292
 293extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 294extern long simple_strtol(const char *,char **,unsigned int);
 295extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 296extern long long simple_strtoll(const char *,char **,unsigned int);
 297#define strict_strtoul  kstrtoul
 298#define strict_strtol   kstrtol
 299#define strict_strtoull kstrtoull
 300#define strict_strtoll  kstrtoll
 301
 302/* lib/printf utilities */
 303
 304extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 305extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 306extern __printf(3, 4)
 307int snprintf(char *buf, size_t size, const char *fmt, ...);
 308extern __printf(3, 0)
 309int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 310extern __printf(3, 4)
 311int scnprintf(char *buf, size_t size, const char *fmt, ...);
 312extern __printf(3, 0)
 313int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 314extern __printf(2, 3)
 315char *kasprintf(gfp_t gfp, const char *fmt, ...);
 316extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 317
 318extern int sscanf(const char *, const char *, ...)
 319        __attribute__ ((format (scanf, 2, 3)));
 320extern int vsscanf(const char *, const char *, va_list)
 321        __attribute__ ((format (scanf, 2, 0)));
 322
 323extern int get_option(char **str, int *pint);
 324extern char *get_options(const char *str, int nints, int *ints);
 325extern unsigned long long memparse(const char *ptr, char **retptr);
 326
 327extern int core_kernel_text(unsigned long addr);
 328extern int core_kernel_data(unsigned long addr);
 329extern int __kernel_text_address(unsigned long addr);
 330extern int kernel_text_address(unsigned long addr);
 331extern int func_ptr_is_kernel_text(void *ptr);
 332
 333struct pid;
 334extern struct pid *session_of_pgrp(struct pid *pgrp);
 335
 336unsigned long int_sqrt(unsigned long);
 337
 338extern void bust_spinlocks(int yes);
 339extern void wake_up_klogd(void);
 340extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 341extern int panic_timeout;
 342extern int panic_on_oops;
 343extern int panic_on_unrecovered_nmi;
 344extern int panic_on_io_nmi;
 345extern int sysctl_panic_on_stackoverflow;
 346extern const char *print_tainted(void);
 347extern void add_taint(unsigned flag);
 348extern int test_taint(unsigned flag);
 349extern unsigned long get_taint(void);
 350extern int root_mountflags;
 351
 352extern bool early_boot_irqs_disabled;
 353
 354/* Values used for system_state */
 355extern enum system_states {
 356        SYSTEM_BOOTING,
 357        SYSTEM_RUNNING,
 358        SYSTEM_HALT,
 359        SYSTEM_POWER_OFF,
 360        SYSTEM_RESTART,
 361        SYSTEM_SUSPEND_DISK,
 362} system_state;
 363
 364#define TAINT_PROPRIETARY_MODULE        0
 365#define TAINT_FORCED_MODULE             1
 366#define TAINT_UNSAFE_SMP                2
 367#define TAINT_FORCED_RMMOD              3
 368#define TAINT_MACHINE_CHECK             4
 369#define TAINT_BAD_PAGE                  5
 370#define TAINT_USER                      6
 371#define TAINT_DIE                       7
 372#define TAINT_OVERRIDDEN_ACPI_TABLE     8
 373#define TAINT_WARN                      9
 374#define TAINT_CRAP                      10
 375#define TAINT_FIRMWARE_WORKAROUND       11
 376#define TAINT_OOT_MODULE                12
 377
 378extern const char hex_asc[];
 379#define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 380#define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 381
 382static inline char *hex_byte_pack(char *buf, u8 byte)
 383{
 384        *buf++ = hex_asc_hi(byte);
 385        *buf++ = hex_asc_lo(byte);
 386        return buf;
 387}
 388
 389static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 390{
 391        return hex_byte_pack(buf, byte);
 392}
 393
 394extern int hex_to_bin(char ch);
 395extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 396
 397/*
 398 * General tracing related utility functions - trace_printk(),
 399 * tracing_on/tracing_off and tracing_start()/tracing_stop
 400 *
 401 * Use tracing_on/tracing_off when you want to quickly turn on or off
 402 * tracing. It simply enables or disables the recording of the trace events.
 403 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 404 * file, which gives a means for the kernel and userspace to interact.
 405 * Place a tracing_off() in the kernel where you want tracing to end.
 406 * From user space, examine the trace, and then echo 1 > tracing_on
 407 * to continue tracing.
 408 *
 409 * tracing_stop/tracing_start has slightly more overhead. It is used
 410 * by things like suspend to ram where disabling the recording of the
 411 * trace is not enough, but tracing must actually stop because things
 412 * like calling smp_processor_id() may crash the system.
 413 *
 414 * Most likely, you want to use tracing_on/tracing_off.
 415 */
 416#ifdef CONFIG_RING_BUFFER
 417void tracing_on(void);
 418void tracing_off(void);
 419/* trace_off_permanent stops recording with no way to bring it back */
 420void tracing_off_permanent(void);
 421int tracing_is_on(void);
 422#else
 423static inline void tracing_on(void) { }
 424static inline void tracing_off(void) { }
 425static inline void tracing_off_permanent(void) { }
 426static inline int tracing_is_on(void) { return 0; }
 427#endif
 428
 429enum ftrace_dump_mode {
 430        DUMP_NONE,
 431        DUMP_ALL,
 432        DUMP_ORIG,
 433};
 434
 435#ifdef CONFIG_TRACING
 436extern void tracing_start(void);
 437extern void tracing_stop(void);
 438extern void ftrace_off_permanent(void);
 439
 440static inline __printf(1, 2)
 441void ____trace_printk_check_format(const char *fmt, ...)
 442{
 443}
 444#define __trace_printk_check_format(fmt, args...)                       \
 445do {                                                                    \
 446        if (0)                                                          \
 447                ____trace_printk_check_format(fmt, ##args);             \
 448} while (0)
 449
 450/**
 451 * trace_printk - printf formatting in the ftrace buffer
 452 * @fmt: the printf format for printing
 453 *
 454 * Note: __trace_printk is an internal function for trace_printk and
 455 *       the @ip is passed in via the trace_printk macro.
 456 *
 457 * This function allows a kernel developer to debug fast path sections
 458 * that printk is not appropriate for. By scattering in various
 459 * printk like tracing in the code, a developer can quickly see
 460 * where problems are occurring.
 461 *
 462 * This is intended as a debugging tool for the developer only.
 463 * Please refrain from leaving trace_printks scattered around in
 464 * your code.
 465 */
 466
 467#define trace_printk(fmt, args...)                                      \
 468do {                                                                    \
 469        __trace_printk_check_format(fmt, ##args);                       \
 470        if (__builtin_constant_p(fmt)) {                                \
 471                static const char *trace_printk_fmt                     \
 472                  __attribute__((section("__trace_printk_fmt"))) =      \
 473                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 474                                                                        \
 475                __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 476        } else                                                          \
 477                __trace_printk(_THIS_IP_, fmt, ##args);         \
 478} while (0)
 479
 480extern __printf(2, 3)
 481int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 482
 483extern __printf(2, 3)
 484int __trace_printk(unsigned long ip, const char *fmt, ...);
 485
 486extern void trace_dump_stack(void);
 487
 488/*
 489 * The double __builtin_constant_p is because gcc will give us an error
 490 * if we try to allocate the static variable to fmt if it is not a
 491 * constant. Even with the outer if statement.
 492 */
 493#define ftrace_vprintk(fmt, vargs)                                      \
 494do {                                                                    \
 495        if (__builtin_constant_p(fmt)) {                                \
 496                static const char *trace_printk_fmt                     \
 497                  __attribute__((section("__trace_printk_fmt"))) =      \
 498                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 499                                                                        \
 500                __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 501        } else                                                          \
 502                __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 503} while (0)
 504
 505extern int
 506__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 507
 508extern int
 509__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 510
 511extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 512#else
 513static inline __printf(1, 2)
 514int trace_printk(const char *fmt, ...);
 515
 516static inline void tracing_start(void) { }
 517static inline void tracing_stop(void) { }
 518static inline void ftrace_off_permanent(void) { }
 519static inline void trace_dump_stack(void) { }
 520static inline int
 521trace_printk(const char *fmt, ...)
 522{
 523        return 0;
 524}
 525static inline int
 526ftrace_vprintk(const char *fmt, va_list ap)
 527{
 528        return 0;
 529}
 530static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 531#endif /* CONFIG_TRACING */
 532
 533/*
 534 * min()/max()/clamp() macros that also do
 535 * strict type-checking.. See the
 536 * "unnecessary" pointer comparison.
 537 */
 538#define min(x, y) ({                            \
 539        typeof(x) _min1 = (x);                  \
 540        typeof(y) _min2 = (y);                  \
 541        (void) (&_min1 == &_min2);              \
 542        _min1 < _min2 ? _min1 : _min2; })
 543
 544#define max(x, y) ({                            \
 545        typeof(x) _max1 = (x);                  \
 546        typeof(y) _max2 = (y);                  \
 547        (void) (&_max1 == &_max2);              \
 548        _max1 > _max2 ? _max1 : _max2; })
 549
 550#define min3(x, y, z) ({                        \
 551        typeof(x) _min1 = (x);                  \
 552        typeof(y) _min2 = (y);                  \
 553        typeof(z) _min3 = (z);                  \
 554        (void) (&_min1 == &_min2);              \
 555        (void) (&_min1 == &_min3);              \
 556        _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 557                (_min2 < _min3 ? _min2 : _min3); })
 558
 559#define max3(x, y, z) ({                        \
 560        typeof(x) _max1 = (x);                  \
 561        typeof(y) _max2 = (y);                  \
 562        typeof(z) _max3 = (z);                  \
 563        (void) (&_max1 == &_max2);              \
 564        (void) (&_max1 == &_max3);              \
 565        _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 566                (_max2 > _max3 ? _max2 : _max3); })
 567
 568/**
 569 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 570 * @x: value1
 571 * @y: value2
 572 */
 573#define min_not_zero(x, y) ({                   \
 574        typeof(x) __x = (x);                    \
 575        typeof(y) __y = (y);                    \
 576        __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 577
 578/**
 579 * clamp - return a value clamped to a given range with strict typechecking
 580 * @val: current value
 581 * @min: minimum allowable value
 582 * @max: maximum allowable value
 583 *
 584 * This macro does strict typechecking of min/max to make sure they are of the
 585 * same type as val.  See the unnecessary pointer comparisons.
 586 */
 587#define clamp(val, min, max) ({                 \
 588        typeof(val) __val = (val);              \
 589        typeof(min) __min = (min);              \
 590        typeof(max) __max = (max);              \
 591        (void) (&__val == &__min);              \
 592        (void) (&__val == &__max);              \
 593        __val = __val < __min ? __min: __val;   \
 594        __val > __max ? __max: __val; })
 595
 596/*
 597 * ..and if you can't take the strict
 598 * types, you can specify one yourself.
 599 *
 600 * Or not use min/max/clamp at all, of course.
 601 */
 602#define min_t(type, x, y) ({                    \
 603        type __min1 = (x);                      \
 604        type __min2 = (y);                      \
 605        __min1 < __min2 ? __min1: __min2; })
 606
 607#define max_t(type, x, y) ({                    \
 608        type __max1 = (x);                      \
 609        type __max2 = (y);                      \
 610        __max1 > __max2 ? __max1: __max2; })
 611
 612/**
 613 * clamp_t - return a value clamped to a given range using a given type
 614 * @type: the type of variable to use
 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 type
 620 * 'type' to make all the comparisons.
 621 */
 622#define clamp_t(type, val, min, max) ({         \
 623        type __val = (val);                     \
 624        type __min = (min);                     \
 625        type __max = (max);                     \
 626        __val = __val < __min ? __min: __val;   \
 627        __val > __max ? __max: __val; })
 628
 629/**
 630 * clamp_val - return a value clamped to a given range using val's type
 631 * @val: current value
 632 * @min: minimum allowable value
 633 * @max: maximum allowable value
 634 *
 635 * This macro does no typechecking and uses temporary variables of whatever
 636 * type the input argument 'val' is.  This is useful when val is an unsigned
 637 * type and min and max are literals that will otherwise be assigned a signed
 638 * integer type.
 639 */
 640#define clamp_val(val, min, max) ({             \
 641        typeof(val) __val = (val);              \
 642        typeof(val) __min = (min);              \
 643        typeof(val) __max = (max);              \
 644        __val = __val < __min ? __min: __val;   \
 645        __val > __max ? __max: __val; })
 646
 647
 648/*
 649 * swap - swap value of @a and @b
 650 */
 651#define swap(a, b) \
 652        do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 653
 654/**
 655 * container_of - cast a member of a structure out to the containing structure
 656 * @ptr:        the pointer to the member.
 657 * @type:       the type of the container struct this is embedded in.
 658 * @member:     the name of the member within the struct.
 659 *
 660 */
 661#define container_of(ptr, type, member) ({                      \
 662        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 663        (type *)( (char *)__mptr - offsetof(type,member) );})
 664
 665#ifdef __CHECKER__
 666#define BUILD_BUG_ON_NOT_POWER_OF_2(n)
 667#define BUILD_BUG_ON_ZERO(e) (0)
 668#define BUILD_BUG_ON_NULL(e) ((void*)0)
 669#define BUILD_BUG_ON(condition)
 670#define BUILD_BUG() (0)
 671#else /* __CHECKER__ */
 672
 673/* Force a compilation error if a constant expression is not a power of 2 */
 674#define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
 675        BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
 676
 677/* Force a compilation error if condition is true, but also produce a
 678   result (of value 0 and type size_t), so the expression can be used
 679   e.g. in a structure initializer (or where-ever else comma expressions
 680   aren't permitted). */
 681#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 682#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
 683
 684/**
 685 * BUILD_BUG_ON - break compile if a condition is true.
 686 * @condition: the condition which the compiler should know is false.
 687 *
 688 * If you have some code which relies on certain constants being equal, or
 689 * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 690 * detect if someone changes it.
 691 *
 692 * The implementation uses gcc's reluctance to create a negative array, but
 693 * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 694 * to inline functions).  So as a fallback we use the optimizer; if it can't
 695 * prove the condition is false, it will cause a link error on the undefined
 696 * "__build_bug_on_failed".  This error message can be harder to track down
 697 * though, hence the two different methods.
 698 */
 699#ifndef __OPTIMIZE__
 700#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 701#else
 702extern int __build_bug_on_failed;
 703#define BUILD_BUG_ON(condition)                                 \
 704        do {                                                    \
 705                ((void)sizeof(char[1 - 2*!!(condition)]));      \
 706                if (condition) __build_bug_on_failed = 1;       \
 707        } while(0)
 708#endif
 709
 710/**
 711 * BUILD_BUG - break compile if used.
 712 *
 713 * If you have some code that you expect the compiler to eliminate at
 714 * build time, you should use BUILD_BUG to detect if it is
 715 * unexpectedly used.
 716 */
 717#define BUILD_BUG()                                             \
 718        do {                                                    \
 719                extern void __build_bug_failed(void)            \
 720                        __linktime_error("BUILD_BUG failed");   \
 721                __build_bug_failed();                           \
 722        } while (0)
 723
 724#endif  /* __CHECKER__ */
 725
 726/* Trap pasters of __FUNCTION__ at compile-time */
 727#define __FUNCTION__ (__func__)
 728
 729/* This helps us to avoid #ifdef CONFIG_NUMA */
 730#ifdef CONFIG_NUMA
 731#define NUMA_BUILD 1
 732#else
 733#define NUMA_BUILD 0
 734#endif
 735
 736/* This helps us avoid #ifdef CONFIG_COMPACTION */
 737#ifdef CONFIG_COMPACTION
 738#define COMPACTION_BUILD 1
 739#else
 740#define COMPACTION_BUILD 0
 741#endif
 742
 743/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 744#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 745# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 746#endif
 747
 748struct sysinfo;
 749extern int do_sysinfo(struct sysinfo *info);
 750
 751#endif /* __KERNEL__ */
 752
 753#define SI_LOAD_SHIFT   16
 754struct sysinfo {
 755        long uptime;                    /* Seconds since boot */
 756        unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 757        unsigned long totalram;         /* Total usable main memory size */
 758        unsigned long freeram;          /* Available memory size */
 759        unsigned long sharedram;        /* Amount of shared memory */
 760        unsigned long bufferram;        /* Memory used by buffers */
 761        unsigned long totalswap;        /* Total swap space size */
 762        unsigned long freeswap;         /* swap space still available */
 763        unsigned short procs;           /* Number of current processes */
 764        unsigned short pad;             /* explicit padding for m68k */
 765        unsigned long totalhigh;        /* Total high memory size */
 766        unsigned long freehigh;         /* Available high memory size */
 767        unsigned int mem_unit;          /* Memory unit size in bytes */
 768        char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 769};
 770
 771#endif
 772