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/*
  89 * Multiplies an integer by a fraction, while avoiding unnecessary
  90 * overflow or loss of precision.
  91 */
  92#define mult_frac(x, numer, denom)(                     \
  93{                                                       \
  94        typeof(x) quot = (x) / (denom);                 \
  95        typeof(x) rem  = (x) % (denom);                 \
  96        (quot * (numer)) + ((rem * (numer)) / (denom)); \
  97}                                                       \
  98)
  99
 100
 101#define _RET_IP_                (unsigned long)__builtin_return_address(0)
 102#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
 103
 104#ifdef CONFIG_LBDAF
 105# include <asm/div64.h>
 106# define sector_div(a, b) do_div(a, b)
 107#else
 108# define sector_div(n, b)( \
 109{ \
 110        int _res; \
 111        _res = (n) % (b); \
 112        (n) /= (b); \
 113        _res; \
 114} \
 115)
 116#endif
 117
 118/**
 119 * upper_32_bits - return bits 32-63 of a number
 120 * @n: the number we're accessing
 121 *
 122 * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
 123 * the "right shift count >= width of type" warning when that quantity is
 124 * 32-bits.
 125 */
 126#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
 127
 128/**
 129 * lower_32_bits - return bits 0-31 of a number
 130 * @n: the number we're accessing
 131 */
 132#define lower_32_bits(n) ((u32)(n))
 133
 134struct completion;
 135struct pt_regs;
 136struct user;
 137
 138#ifdef CONFIG_PREEMPT_VOLUNTARY
 139extern int _cond_resched(void);
 140# define might_resched() _cond_resched()
 141#else
 142# define might_resched() do { } while (0)
 143#endif
 144
 145#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 146  void __might_sleep(const char *file, int line, int preempt_offset);
 147/**
 148 * might_sleep - annotation for functions that can sleep
 149 *
 150 * this macro will print a stack trace if it is executed in an atomic
 151 * context (spinlock, irq-handler, ...).
 152 *
 153 * This is a useful debugging help to be able to catch problems early and not
 154 * be bitten later when the calling function happens to sleep when it is not
 155 * supposed to.
 156 */
 157# define might_sleep() \
 158        do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 159#else
 160  static inline void __might_sleep(const char *file, int line,
 161                                   int preempt_offset) { }
 162# define might_sleep() do { might_resched(); } while (0)
 163#endif
 164
 165#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 166
 167/*
 168 * abs() handles unsigned and signed longs, ints, shorts and chars.  For all
 169 * input types abs() returns a signed long.
 170 * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
 171 * for those.
 172 */
 173#define abs(x) ({                                               \
 174                long ret;                                       \
 175                if (sizeof(x) == sizeof(long)) {                \
 176                        long __x = (x);                         \
 177                        ret = (__x < 0) ? -__x : __x;           \
 178                } else {                                        \
 179                        int __x = (x);                          \
 180                        ret = (__x < 0) ? -__x : __x;           \
 181                }                                               \
 182                ret;                                            \
 183        })
 184
 185#define abs64(x) ({                             \
 186                s64 __x = (x);                  \
 187                (__x < 0) ? -__x : __x;         \
 188        })
 189
 190#ifdef CONFIG_PROVE_LOCKING
 191void might_fault(void);
 192#else
 193static inline void might_fault(void)
 194{
 195        might_sleep();
 196}
 197#endif
 198
 199extern struct atomic_notifier_head panic_notifier_list;
 200extern long (*panic_blink)(int state);
 201__printf(1, 2)
 202void panic(const char *fmt, ...)
 203        __noreturn __cold;
 204extern void oops_enter(void);
 205extern void oops_exit(void);
 206void print_oops_end_marker(void);
 207extern int oops_may_print(void);
 208void do_exit(long error_code)
 209        __noreturn;
 210void complete_and_exit(struct completion *, long)
 211        __noreturn;
 212
 213/* Internal, do not use. */
 214int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 215int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 216
 217int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 218int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 219static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 220{
 221        /*
 222         * We want to shortcut function call, but
 223         * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 224         */
 225        if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 226            __alignof__(unsigned long) == __alignof__(unsigned long long))
 227                return kstrtoull(s, base, (unsigned long long *)res);
 228        else
 229                return _kstrtoul(s, base, res);
 230}
 231
 232static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 233{
 234        /*
 235         * We want to shortcut function call, but
 236         * __builtin_types_compatible_p(long, long long) = 0.
 237         */
 238        if (sizeof(long) == sizeof(long long) &&
 239            __alignof__(long) == __alignof__(long long))
 240                return kstrtoll(s, base, (long long *)res);
 241        else
 242                return _kstrtol(s, base, res);
 243}
 244
 245int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 246int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 247
 248static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 249{
 250        return kstrtoull(s, base, res);
 251}
 252
 253static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 254{
 255        return kstrtoll(s, base, res);
 256}
 257
 258static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 259{
 260        return kstrtouint(s, base, res);
 261}
 262
 263static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 264{
 265        return kstrtoint(s, base, res);
 266}
 267
 268int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 269int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 270int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 271int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 272
 273int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 274int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 275int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 276int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 277int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 278int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 279int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 280int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 281int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 282int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 283
 284static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 285{
 286        return kstrtoull_from_user(s, count, base, res);
 287}
 288
 289static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 290{
 291        return kstrtoll_from_user(s, count, base, res);
 292}
 293
 294static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 295{
 296        return kstrtouint_from_user(s, count, base, res);
 297}
 298
 299static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 300{
 301        return kstrtoint_from_user(s, count, base, res);
 302}
 303
 304/* Obsolete, do not use.  Use kstrto<foo> instead */
 305
 306extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 307extern long simple_strtol(const char *,char **,unsigned int);
 308extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 309extern long long simple_strtoll(const char *,char **,unsigned int);
 310#define strict_strtoul  kstrtoul
 311#define strict_strtol   kstrtol
 312#define strict_strtoull kstrtoull
 313#define strict_strtoll  kstrtoll
 314
 315/* lib/printf utilities */
 316
 317extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 318extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 319extern __printf(3, 4)
 320int snprintf(char *buf, size_t size, const char *fmt, ...);
 321extern __printf(3, 0)
 322int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 323extern __printf(3, 4)
 324int scnprintf(char *buf, size_t size, const char *fmt, ...);
 325extern __printf(3, 0)
 326int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 327extern __printf(2, 3)
 328char *kasprintf(gfp_t gfp, const char *fmt, ...);
 329extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 330
 331extern int sscanf(const char *, const char *, ...)
 332        __attribute__ ((format (scanf, 2, 3)));
 333extern int vsscanf(const char *, const char *, va_list)
 334        __attribute__ ((format (scanf, 2, 0)));
 335
 336extern int get_option(char **str, int *pint);
 337extern char *get_options(const char *str, int nints, int *ints);
 338extern unsigned long long memparse(const char *ptr, char **retptr);
 339
 340extern int core_kernel_text(unsigned long addr);
 341extern int core_kernel_data(unsigned long addr);
 342extern int __kernel_text_address(unsigned long addr);
 343extern int kernel_text_address(unsigned long addr);
 344extern int func_ptr_is_kernel_text(void *ptr);
 345
 346struct pid;
 347extern struct pid *session_of_pgrp(struct pid *pgrp);
 348
 349unsigned long int_sqrt(unsigned long);
 350
 351extern void bust_spinlocks(int yes);
 352extern void wake_up_klogd(void);
 353extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 354extern int panic_timeout;
 355extern int panic_on_oops;
 356extern int panic_on_unrecovered_nmi;
 357extern int panic_on_io_nmi;
 358extern int sysctl_panic_on_stackoverflow;
 359extern const char *print_tainted(void);
 360extern void add_taint(unsigned flag);
 361extern int test_taint(unsigned flag);
 362extern unsigned long get_taint(void);
 363extern int root_mountflags;
 364
 365extern bool early_boot_irqs_disabled;
 366
 367/* Values used for system_state */
 368extern enum system_states {
 369        SYSTEM_BOOTING,
 370        SYSTEM_RUNNING,
 371        SYSTEM_HALT,
 372        SYSTEM_POWER_OFF,
 373        SYSTEM_RESTART,
 374        SYSTEM_SUSPEND_DISK,
 375} system_state;
 376
 377#define TAINT_PROPRIETARY_MODULE        0
 378#define TAINT_FORCED_MODULE             1
 379#define TAINT_UNSAFE_SMP                2
 380#define TAINT_FORCED_RMMOD              3
 381#define TAINT_MACHINE_CHECK             4
 382#define TAINT_BAD_PAGE                  5
 383#define TAINT_USER                      6
 384#define TAINT_DIE                       7
 385#define TAINT_OVERRIDDEN_ACPI_TABLE     8
 386#define TAINT_WARN                      9
 387#define TAINT_CRAP                      10
 388#define TAINT_FIRMWARE_WORKAROUND       11
 389#define TAINT_OOT_MODULE                12
 390
 391extern const char hex_asc[];
 392#define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 393#define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 394
 395static inline char *hex_byte_pack(char *buf, u8 byte)
 396{
 397        *buf++ = hex_asc_hi(byte);
 398        *buf++ = hex_asc_lo(byte);
 399        return buf;
 400}
 401
 402static inline char * __deprecated pack_hex_byte(char *buf, u8 byte)
 403{
 404        return hex_byte_pack(buf, byte);
 405}
 406
 407extern int hex_to_bin(char ch);
 408extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 409
 410/*
 411 * General tracing related utility functions - trace_printk(),
 412 * tracing_on/tracing_off and tracing_start()/tracing_stop
 413 *
 414 * Use tracing_on/tracing_off when you want to quickly turn on or off
 415 * tracing. It simply enables or disables the recording of the trace events.
 416 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 417 * file, which gives a means for the kernel and userspace to interact.
 418 * Place a tracing_off() in the kernel where you want tracing to end.
 419 * From user space, examine the trace, and then echo 1 > tracing_on
 420 * to continue tracing.
 421 *
 422 * tracing_stop/tracing_start has slightly more overhead. It is used
 423 * by things like suspend to ram where disabling the recording of the
 424 * trace is not enough, but tracing must actually stop because things
 425 * like calling smp_processor_id() may crash the system.
 426 *
 427 * Most likely, you want to use tracing_on/tracing_off.
 428 */
 429#ifdef CONFIG_RING_BUFFER
 430void tracing_on(void);
 431void tracing_off(void);
 432/* trace_off_permanent stops recording with no way to bring it back */
 433void tracing_off_permanent(void);
 434int tracing_is_on(void);
 435#else
 436static inline void tracing_on(void) { }
 437static inline void tracing_off(void) { }
 438static inline void tracing_off_permanent(void) { }
 439static inline int tracing_is_on(void) { return 0; }
 440#endif
 441
 442enum ftrace_dump_mode {
 443        DUMP_NONE,
 444        DUMP_ALL,
 445        DUMP_ORIG,
 446};
 447
 448#ifdef CONFIG_TRACING
 449extern void tracing_start(void);
 450extern void tracing_stop(void);
 451extern void ftrace_off_permanent(void);
 452
 453static inline __printf(1, 2)
 454void ____trace_printk_check_format(const char *fmt, ...)
 455{
 456}
 457#define __trace_printk_check_format(fmt, args...)                       \
 458do {                                                                    \
 459        if (0)                                                          \
 460                ____trace_printk_check_format(fmt, ##args);             \
 461} while (0)
 462
 463/**
 464 * trace_printk - printf formatting in the ftrace buffer
 465 * @fmt: the printf format for printing
 466 *
 467 * Note: __trace_printk is an internal function for trace_printk and
 468 *       the @ip is passed in via the trace_printk macro.
 469 *
 470 * This function allows a kernel developer to debug fast path sections
 471 * that printk is not appropriate for. By scattering in various
 472 * printk like tracing in the code, a developer can quickly see
 473 * where problems are occurring.
 474 *
 475 * This is intended as a debugging tool for the developer only.
 476 * Please refrain from leaving trace_printks scattered around in
 477 * your code.
 478 */
 479
 480#define trace_printk(fmt, args...)                                      \
 481do {                                                                    \
 482        __trace_printk_check_format(fmt, ##args);                       \
 483        if (__builtin_constant_p(fmt)) {                                \
 484                static const char *trace_printk_fmt                     \
 485                  __attribute__((section("__trace_printk_fmt"))) =      \
 486                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 487                                                                        \
 488                __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 489        } else                                                          \
 490                __trace_printk(_THIS_IP_, fmt, ##args);         \
 491} while (0)
 492
 493extern __printf(2, 3)
 494int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 495
 496extern __printf(2, 3)
 497int __trace_printk(unsigned long ip, const char *fmt, ...);
 498
 499extern void trace_dump_stack(void);
 500
 501/*
 502 * The double __builtin_constant_p is because gcc will give us an error
 503 * if we try to allocate the static variable to fmt if it is not a
 504 * constant. Even with the outer if statement.
 505 */
 506#define ftrace_vprintk(fmt, vargs)                                      \
 507do {                                                                    \
 508        if (__builtin_constant_p(fmt)) {                                \
 509                static const char *trace_printk_fmt                     \
 510                  __attribute__((section("__trace_printk_fmt"))) =      \
 511                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 512                                                                        \
 513                __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 514        } else                                                          \
 515                __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 516} while (0)
 517
 518extern int
 519__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 520
 521extern int
 522__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 523
 524extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 525#else
 526static inline __printf(1, 2)
 527int trace_printk(const char *fmt, ...);
 528
 529static inline void tracing_start(void) { }
 530static inline void tracing_stop(void) { }
 531static inline void ftrace_off_permanent(void) { }
 532static inline void trace_dump_stack(void) { }
 533static inline int
 534trace_printk(const char *fmt, ...)
 535{
 536        return 0;
 537}
 538static inline int
 539ftrace_vprintk(const char *fmt, va_list ap)
 540{
 541        return 0;
 542}
 543static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 544#endif /* CONFIG_TRACING */
 545
 546/*
 547 * min()/max()/clamp() macros that also do
 548 * strict type-checking.. See the
 549 * "unnecessary" pointer comparison.
 550 */
 551#define min(x, y) ({                            \
 552        typeof(x) _min1 = (x);                  \
 553        typeof(y) _min2 = (y);                  \
 554        (void) (&_min1 == &_min2);              \
 555        _min1 < _min2 ? _min1 : _min2; })
 556
 557#define max(x, y) ({                            \
 558        typeof(x) _max1 = (x);                  \
 559        typeof(y) _max2 = (y);                  \
 560        (void) (&_max1 == &_max2);              \
 561        _max1 > _max2 ? _max1 : _max2; })
 562
 563#define min3(x, y, z) ({                        \
 564        typeof(x) _min1 = (x);                  \
 565        typeof(y) _min2 = (y);                  \
 566        typeof(z) _min3 = (z);                  \
 567        (void) (&_min1 == &_min2);              \
 568        (void) (&_min1 == &_min3);              \
 569        _min1 < _min2 ? (_min1 < _min3 ? _min1 : _min3) : \
 570                (_min2 < _min3 ? _min2 : _min3); })
 571
 572#define max3(x, y, z) ({                        \
 573        typeof(x) _max1 = (x);                  \
 574        typeof(y) _max2 = (y);                  \
 575        typeof(z) _max3 = (z);                  \
 576        (void) (&_max1 == &_max2);              \
 577        (void) (&_max1 == &_max3);              \
 578        _max1 > _max2 ? (_max1 > _max3 ? _max1 : _max3) : \
 579                (_max2 > _max3 ? _max2 : _max3); })
 580
 581/**
 582 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
 583 * @x: value1
 584 * @y: value2
 585 */
 586#define min_not_zero(x, y) ({                   \
 587        typeof(x) __x = (x);                    \
 588        typeof(y) __y = (y);                    \
 589        __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 590
 591/**
 592 * clamp - return a value clamped to a given range with strict typechecking
 593 * @val: current value
 594 * @min: minimum allowable value
 595 * @max: maximum allowable value
 596 *
 597 * This macro does strict typechecking of min/max to make sure they are of the
 598 * same type as val.  See the unnecessary pointer comparisons.
 599 */
 600#define clamp(val, min, max) ({                 \
 601        typeof(val) __val = (val);              \
 602        typeof(min) __min = (min);              \
 603        typeof(max) __max = (max);              \
 604        (void) (&__val == &__min);              \
 605        (void) (&__val == &__max);              \
 606        __val = __val < __min ? __min: __val;   \
 607        __val > __max ? __max: __val; })
 608
 609/*
 610 * ..and if you can't take the strict
 611 * types, you can specify one yourself.
 612 *
 613 * Or not use min/max/clamp at all, of course.
 614 */
 615#define min_t(type, x, y) ({                    \
 616        type __min1 = (x);                      \
 617        type __min2 = (y);                      \
 618        __min1 < __min2 ? __min1: __min2; })
 619
 620#define max_t(type, x, y) ({                    \
 621        type __max1 = (x);                      \
 622        type __max2 = (y);                      \
 623        __max1 > __max2 ? __max1: __max2; })
 624
 625/**
 626 * clamp_t - return a value clamped to a given range using a given type
 627 * @type: the type of variable to use
 628 * @val: current value
 629 * @min: minimum allowable value
 630 * @max: maximum allowable value
 631 *
 632 * This macro does no typechecking and uses temporary variables of type
 633 * 'type' to make all the comparisons.
 634 */
 635#define clamp_t(type, val, min, max) ({         \
 636        type __val = (val);                     \
 637        type __min = (min);                     \
 638        type __max = (max);                     \
 639        __val = __val < __min ? __min: __val;   \
 640        __val > __max ? __max: __val; })
 641
 642/**
 643 * clamp_val - return a value clamped to a given range using val's type
 644 * @val: current value
 645 * @min: minimum allowable value
 646 * @max: maximum allowable value
 647 *
 648 * This macro does no typechecking and uses temporary variables of whatever
 649 * type the input argument 'val' is.  This is useful when val is an unsigned
 650 * type and min and max are literals that will otherwise be assigned a signed
 651 * integer type.
 652 */
 653#define clamp_val(val, min, max) ({             \
 654        typeof(val) __val = (val);              \
 655        typeof(val) __min = (min);              \
 656        typeof(val) __max = (max);              \
 657        __val = __val < __min ? __min: __val;   \
 658        __val > __max ? __max: __val; })
 659
 660
 661/*
 662 * swap - swap value of @a and @b
 663 */
 664#define swap(a, b) \
 665        do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 666
 667/**
 668 * container_of - cast a member of a structure out to the containing structure
 669 * @ptr:        the pointer to the member.
 670 * @type:       the type of the container struct this is embedded in.
 671 * @member:     the name of the member within the struct.
 672 *
 673 */
 674#define container_of(ptr, type, member) ({                      \
 675        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 676        (type *)( (char *)__mptr - offsetof(type,member) );})
 677
 678#ifdef __CHECKER__
 679#define BUILD_BUG_ON_NOT_POWER_OF_2(n)
 680#define BUILD_BUG_ON_ZERO(e) (0)
 681#define BUILD_BUG_ON_NULL(e) ((void*)0)
 682#define BUILD_BUG_ON(condition)
 683#define BUILD_BUG() (0)
 684#else /* __CHECKER__ */
 685
 686/* Force a compilation error if a constant expression is not a power of 2 */
 687#define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
 688        BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
 689
 690/* Force a compilation error if condition is true, but also produce a
 691   result (of value 0 and type size_t), so the expression can be used
 692   e.g. in a structure initializer (or where-ever else comma expressions
 693   aren't permitted). */
 694#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
 695#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
 696
 697/**
 698 * BUILD_BUG_ON - break compile if a condition is true.
 699 * @condition: the condition which the compiler should know is false.
 700 *
 701 * If you have some code which relies on certain constants being equal, or
 702 * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
 703 * detect if someone changes it.
 704 *
 705 * The implementation uses gcc's reluctance to create a negative array, but
 706 * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
 707 * to inline functions).  So as a fallback we use the optimizer; if it can't
 708 * prove the condition is false, it will cause a link error on the undefined
 709 * "__build_bug_on_failed".  This error message can be harder to track down
 710 * though, hence the two different methods.
 711 */
 712#ifndef __OPTIMIZE__
 713#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 714#else
 715extern int __build_bug_on_failed;
 716#define BUILD_BUG_ON(condition)                                 \
 717        do {                                                    \
 718                ((void)sizeof(char[1 - 2*!!(condition)]));      \
 719                if (condition) __build_bug_on_failed = 1;       \
 720        } while(0)
 721#endif
 722
 723/**
 724 * BUILD_BUG - break compile if used.
 725 *
 726 * If you have some code that you expect the compiler to eliminate at
 727 * build time, you should use BUILD_BUG to detect if it is
 728 * unexpectedly used.
 729 */
 730#define BUILD_BUG()                                             \
 731        do {                                                    \
 732                extern void __build_bug_failed(void)            \
 733                        __linktime_error("BUILD_BUG failed");   \
 734                __build_bug_failed();                           \
 735        } while (0)
 736
 737#endif  /* __CHECKER__ */
 738
 739/* Trap pasters of __FUNCTION__ at compile-time */
 740#define __FUNCTION__ (__func__)
 741
 742/* This helps us to avoid #ifdef CONFIG_NUMA */
 743#ifdef CONFIG_NUMA
 744#define NUMA_BUILD 1
 745#else
 746#define NUMA_BUILD 0
 747#endif
 748
 749/* This helps us avoid #ifdef CONFIG_COMPACTION */
 750#ifdef CONFIG_COMPACTION
 751#define COMPACTION_BUILD 1
 752#else
 753#define COMPACTION_BUILD 0
 754#endif
 755
 756/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 757#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 758# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 759#endif
 760
 761struct sysinfo;
 762extern int do_sysinfo(struct sysinfo *info);
 763
 764#endif /* __KERNEL__ */
 765
 766#define SI_LOAD_SHIFT   16
 767struct sysinfo {
 768        long uptime;                    /* Seconds since boot */
 769        unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 770        unsigned long totalram;         /* Total usable main memory size */
 771        unsigned long freeram;          /* Available memory size */
 772        unsigned long sharedram;        /* Amount of shared memory */
 773        unsigned long bufferram;        /* Memory used by buffers */
 774        unsigned long totalswap;        /* Total swap space size */
 775        unsigned long freeswap;         /* swap space still available */
 776        unsigned short procs;           /* Number of current processes */
 777        unsigned short pad;             /* explicit padding for m68k */
 778        unsigned long totalhigh;        /* Total high memory size */
 779        unsigned long freehigh;         /* Available high memory size */
 780        unsigned int mem_unit;          /* Memory unit size in bytes */
 781        char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 782};
 783
 784#endif
 785
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