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
   8#ifdef __KERNEL__
   9
  10#include <stdarg.h>
  11#include <linux/linkage.h>
  12#include <linux/stddef.h>
  13#include <linux/types.h>
  14#include <linux/compiler.h>
  15#include <linux/bitops.h>
  16#include <linux/log2.h>
  17#include <linux/typecheck.h>
  18#include <linux/ratelimit.h>
  19#include <linux/dynamic_debug.h>
  20#include <asm/byteorder.h>
  21#include <asm/bug.h>
  22
  23extern const char linux_banner[];
  24extern const char linux_proc_banner[];
  25
  26#define USHORT_MAX      ((u16)(~0U))
  27#define SHORT_MAX       ((s16)(USHORT_MAX>>1))
  28#define SHORT_MIN       (-SHORT_MAX - 1)
  29#define INT_MAX         ((int)(~0U>>1))
  30#define INT_MIN         (-INT_MAX - 1)
  31#define UINT_MAX        (~0U)
  32#define LONG_MAX        ((long)(~0UL>>1))
  33#define LONG_MIN        (-LONG_MAX - 1)
  34#define ULONG_MAX       (~0UL)
  35#define LLONG_MAX       ((long long)(~0ULL>>1))
  36#define LLONG_MIN       (-LLONG_MAX - 1)
  37#define ULLONG_MAX      (~0ULL)
  38
  39#define STACK_MAGIC     0xdeadbeef
  40
  41#define ALIGN(x,a)              __ALIGN_MASK(x,(typeof(x))(a)-1)
  42#define __ALIGN_MASK(x,mask)    (((x)+(mask))&~(mask))
  43#define PTR_ALIGN(p, a)         ((typeof(p))ALIGN((unsigned long)(p), (a)))
  44#define IS_ALIGNED(x, a)                (((x) & ((typeof(x))(a) - 1)) == 0)
  45
  46#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  47
  48#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
  49#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
  50#define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y))
  51#define DIV_ROUND_CLOSEST(x, divisor)(                  \
  52{                                                       \
  53        typeof(divisor) __divisor = divisor;            \
  54        (((x) + ((__divisor) / 2)) / (__divisor));      \
  55}                                                       \
  56)
  57
  58#define _RET_IP_                (unsigned long)__builtin_return_address(0)
  59#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
  60
  61#ifdef CONFIG_LBD
  62# include <asm/div64.h>
  63# define sector_div(a, b) do_div(a, b)
  64#else
  65# define sector_div(n, b)( \
  66{ \
  67        int _res; \
  68        _res = (n) % (b); \
  69        (n) /= (b); \
  70        _res; \
  71} \
  72)
  73#endif
  74
  75/**
  76 * upper_32_bits - return bits 32-63 of a number
  77 * @n: the number we're accessing
  78 *
  79 * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
  80 * the "right shift count >= width of type" warning when that quantity is
  81 * 32-bits.
  82 */
  83#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
  84
  85/**
  86 * lower_32_bits - return bits 0-31 of a number
  87 * @n: the number we're accessing
  88 */
  89#define lower_32_bits(n) ((u32)(n))
  90
  91#define KERN_EMERG      "<0>"   /* system is unusable                   */
  92#define KERN_ALERT      "<1>"   /* action must be taken immediately     */
  93#define KERN_CRIT       "<2>"   /* critical conditions                  */
  94#define KERN_ERR        "<3>"   /* error conditions                     */
  95#define KERN_WARNING    "<4>"   /* warning conditions                   */
  96#define KERN_NOTICE     "<5>"   /* normal but significant condition     */
  97#define KERN_INFO       "<6>"   /* informational                        */
  98#define KERN_DEBUG      "<7>"   /* debug-level messages                 */
  99
 100/*
 101 * Annotation for a "continued" line of log printout (only done after a
 102 * line that had no enclosing \n). Only to be used by core/arch code
 103 * during early bootup (a continued line is not SMP-safe otherwise).
 104 */
 105#define KERN_CONT       ""
 106
 107extern int console_printk[];
 108
 109#define console_loglevel (console_printk[0])
 110#define default_message_loglevel (console_printk[1])
 111#define minimum_console_loglevel (console_printk[2])
 112#define default_console_loglevel (console_printk[3])
 113
 114struct completion;
 115struct pt_regs;
 116struct user;
 117
 118#ifdef CONFIG_PREEMPT_VOLUNTARY
 119extern int _cond_resched(void);
 120# define might_resched() _cond_resched()
 121#else
 122# define might_resched() do { } while (0)
 123#endif
 124
 125#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
 126  void __might_sleep(char *file, int line);
 127/**
 128 * might_sleep - annotation for functions that can sleep
 129 *
 130 * this macro will print a stack trace if it is executed in an atomic
 131 * context (spinlock, irq-handler, ...).
 132 *
 133 * This is a useful debugging help to be able to catch problems early and not
 134 * be bitten later when the calling function happens to sleep when it is not
 135 * supposed to.
 136 */
 137# define might_sleep() \
 138        do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
 139#else
 140# define might_sleep() do { might_resched(); } while (0)
 141#endif
 142
 143#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 144
 145#define abs(x) ({                               \
 146                int __x = (x);                  \
 147                (__x < 0) ? -__x : __x;         \
 148        })
 149
 150#ifdef CONFIG_PROVE_LOCKING
 151void might_fault(void);
 152#else
 153static inline void might_fault(void)
 154{
 155        might_sleep();
 156}
 157#endif
 158
 159extern struct atomic_notifier_head panic_notifier_list;
 160extern long (*panic_blink)(long time);
 161NORET_TYPE void panic(const char * fmt, ...)
 162        __attribute__ ((NORET_AND format (printf, 1, 2))) __cold;
 163extern void oops_enter(void);
 164extern void oops_exit(void);
 165extern int oops_may_print(void);
 166NORET_TYPE void do_exit(long error_code)
 167        ATTRIB_NORET;
 168NORET_TYPE void complete_and_exit(struct completion *, long)
 169        ATTRIB_NORET;
 170extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 171extern long simple_strtol(const char *,char **,unsigned int);
 172extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 173extern long long simple_strtoll(const char *,char **,unsigned int);
 174extern int strict_strtoul(const char *, unsigned int, unsigned long *);
 175extern int strict_strtol(const char *, unsigned int, long *);
 176extern int strict_strtoull(const char *, unsigned int, unsigned long long *);
 177extern int strict_strtoll(const char *, unsigned int, long long *);
 178extern int sprintf(char * buf, const char * fmt, ...)
 179        __attribute__ ((format (printf, 2, 3)));
 180extern int vsprintf(char *buf, const char *, va_list)
 181        __attribute__ ((format (printf, 2, 0)));
 182extern int snprintf(char * buf, size_t size, const char * fmt, ...)
 183        __attribute__ ((format (printf, 3, 4)));
 184extern int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 185        __attribute__ ((format (printf, 3, 0)));
 186extern int scnprintf(char * buf, size_t size, const char * fmt, ...)
 187        __attribute__ ((format (printf, 3, 4)));
 188extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 189        __attribute__ ((format (printf, 3, 0)));
 190extern char *kasprintf(gfp_t gfp, const char *fmt, ...)
 191        __attribute__ ((format (printf, 2, 3)));
 192extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 193
 194extern int sscanf(const char *, const char *, ...)
 195        __attribute__ ((format (scanf, 2, 3)));
 196extern int vsscanf(const char *, const char *, va_list)
 197        __attribute__ ((format (scanf, 2, 0)));
 198
 199extern int get_option(char **str, int *pint);
 200extern char *get_options(const char *str, int nints, int *ints);
 201extern unsigned long long memparse(const char *ptr, char **retptr);
 202
 203extern int core_kernel_text(unsigned long addr);
 204extern int __kernel_text_address(unsigned long addr);
 205extern int kernel_text_address(unsigned long addr);
 206extern int func_ptr_is_kernel_text(void *ptr);
 207
 208struct pid;
 209extern struct pid *session_of_pgrp(struct pid *pgrp);
 210
 211/*
 212 * FW_BUG
 213 * Add this to a message where you are sure the firmware is buggy or behaves
 214 * really stupid or out of spec. Be aware that the responsible BIOS developer
 215 * should be able to fix this issue or at least get a concrete idea of the
 216 * problem by reading your message without the need of looking at the kernel
 217 * code.
 218 * 
 219 * Use it for definite and high priority BIOS bugs.
 220 *
 221 * FW_WARN
 222 * Use it for not that clear (e.g. could the kernel messed up things already?)
 223 * and medium priority BIOS bugs.
 224 *
 225 * FW_INFO
 226 * Use this one if you want to tell the user or vendor about something
 227 * suspicious, but generally harmless related to the firmware.
 228 *
 229 * Use it for information or very low priority BIOS bugs.
 230 */
 231#define FW_BUG          "[Firmware Bug]: "
 232#define FW_WARN         "[Firmware Warn]: "
 233#define FW_INFO         "[Firmware Info]: "
 234
 235#ifdef CONFIG_PRINTK
 236asmlinkage int vprintk(const char *fmt, va_list args)
 237        __attribute__ ((format (printf, 1, 0)));
 238asmlinkage int printk(const char * fmt, ...)
 239        __attribute__ ((format (printf, 1, 2))) __cold;
 240
 241extern struct ratelimit_state printk_ratelimit_state;
 242extern int printk_ratelimit(void);
 243extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 244                                   unsigned int interval_msec);
 245
 246/*
 247 * Print a one-time message (analogous to WARN_ONCE() et al):
 248 */
 249#define printk_once(x...) ({                    \
 250        static int __print_once = 1;            \
 251                                                \
 252        if (__print_once) {                     \
 253                __print_once = 0;               \
 254                printk(x);                      \
 255        }                                       \
 256})
 257
 258void log_buf_kexec_setup(void);
 259#else
 260static inline int vprintk(const char *s, va_list args)
 261        __attribute__ ((format (printf, 1, 0)));
 262static inline int vprintk(const char *s, va_list args) { return 0; }
 263static inline int printk(const char *s, ...)
 264        __attribute__ ((format (printf, 1, 2)));
 265static inline int __cold printk(const char *s, ...) { return 0; }
 266static inline int printk_ratelimit(void) { return 0; }
 267static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies, \
 268                                          unsigned int interval_msec)   \
 269                { return false; }
 270
 271/* No effect, but we still get type checking even in the !PRINTK case: */
 272#define printk_once(x...) printk(x)
 273
 274static inline void log_buf_kexec_setup(void)
 275{
 276}
 277#endif
 278
 279extern int printk_needs_cpu(int cpu);
 280extern void printk_tick(void);
 281
 282extern void asmlinkage __attribute__((format(printf, 1, 2)))
 283        early_printk(const char *fmt, ...);
 284
 285unsigned long int_sqrt(unsigned long);
 286
 287static inline void console_silent(void)
 288{
 289        console_loglevel = 0;
 290}
 291
 292static inline void console_verbose(void)
 293{
 294        if (console_loglevel)
 295                console_loglevel = 15;
 296}
 297
 298extern void bust_spinlocks(int yes);
 299extern void wake_up_klogd(void);
 300extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 301extern int panic_timeout;
 302extern int panic_on_oops;
 303extern int panic_on_unrecovered_nmi;
 304extern const char *print_tainted(void);
 305extern void add_taint(unsigned flag);
 306extern int test_taint(unsigned flag);
 307extern unsigned long get_taint(void);
 308extern int root_mountflags;
 309
 310/* Values used for system_state */
 311extern enum system_states {
 312        SYSTEM_BOOTING,
 313        SYSTEM_RUNNING,
 314        SYSTEM_HALT,
 315        SYSTEM_POWER_OFF,
 316        SYSTEM_RESTART,
 317        SYSTEM_SUSPEND_DISK,
 318} system_state;
 319
 320#define TAINT_PROPRIETARY_MODULE        0
 321#define TAINT_FORCED_MODULE             1
 322#define TAINT_UNSAFE_SMP                2
 323#define TAINT_FORCED_RMMOD              3
 324#define TAINT_MACHINE_CHECK             4
 325#define TAINT_BAD_PAGE                  5
 326#define TAINT_USER                      6
 327#define TAINT_DIE                       7
 328#define TAINT_OVERRIDDEN_ACPI_TABLE     8
 329#define TAINT_WARN                      9
 330#define TAINT_CRAP                      10
 331
 332extern void dump_stack(void) __cold;
 333
 334enum {
 335        DUMP_PREFIX_NONE,
 336        DUMP_PREFIX_ADDRESS,
 337        DUMP_PREFIX_OFFSET
 338};
 339extern void hex_dump_to_buffer(const void *buf, size_t len,
 340                                int rowsize, int groupsize,
 341                                char *linebuf, size_t linebuflen, bool ascii);
 342extern void print_hex_dump(const char *level, const char *prefix_str,
 343                                int prefix_type, int rowsize, int groupsize,
 344                                const void *buf, size_t len, bool ascii);
 345extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 346                        const void *buf, size_t len);
 347
 348extern const char hex_asc[];
 349#define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 350#define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 351
 352static inline char *pack_hex_byte(char *buf, u8 byte)
 353{
 354        *buf++ = hex_asc_hi(byte);
 355        *buf++ = hex_asc_lo(byte);
 356        return buf;
 357}
 358
 359#ifndef pr_fmt
 360#define pr_fmt(fmt) fmt
 361#endif
 362
 363#define pr_emerg(fmt, ...) \
 364        printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
 365#define pr_alert(fmt, ...) \
 366        printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
 367#define pr_crit(fmt, ...) \
 368        printk(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
 369#define pr_err(fmt, ...) \
 370        printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
 371#define pr_warning(fmt, ...) \
 372        printk(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
 373#define pr_notice(fmt, ...) \
 374        printk(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
 375#define pr_info(fmt, ...) \
 376        printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
 377#define pr_cont(fmt, ...) \
 378        printk(KERN_CONT fmt, ##__VA_ARGS__)
 379
 380/* pr_devel() should produce zero code unless DEBUG is defined */
 381#ifdef DEBUG
 382#define pr_devel(fmt, ...) \
 383        printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 384#else
 385#define pr_devel(fmt, ...) \
 386        ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; })
 387#endif
 388
 389/* If you are writing a driver, please use dev_dbg instead */
 390#if defined(DEBUG)
 391#define pr_debug(fmt, ...) \
 392        printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 393#elif defined(CONFIG_DYNAMIC_DEBUG)
 394/* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
 395#define pr_debug(fmt, ...) do { \
 396        dynamic_pr_debug(fmt, ##__VA_ARGS__); \
 397        } while (0)
 398#else
 399#define pr_debug(fmt, ...) \
 400        ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; })
 401#endif
 402
 403/*
 404 * General tracing related utility functions - trace_printk(),
 405 * tracing_on/tracing_off and tracing_start()/tracing_stop
 406 *
 407 * Use tracing_on/tracing_off when you want to quickly turn on or off
 408 * tracing. It simply enables or disables the recording of the trace events.
 409 * This also corresponds to the user space debugfs/tracing/tracing_on
 410 * file, which gives a means for the kernel and userspace to interact.
 411 * Place a tracing_off() in the kernel where you want tracing to end.
 412 * From user space, examine the trace, and then echo 1 > tracing_on
 413 * to continue tracing.
 414 *
 415 * tracing_stop/tracing_start has slightly more overhead. It is used
 416 * by things like suspend to ram where disabling the recording of the
 417 * trace is not enough, but tracing must actually stop because things
 418 * like calling smp_processor_id() may crash the system.
 419 *
 420 * Most likely, you want to use tracing_on/tracing_off.
 421 */
 422#ifdef CONFIG_RING_BUFFER
 423void tracing_on(void);
 424void tracing_off(void);
 425/* trace_off_permanent stops recording with no way to bring it back */
 426void tracing_off_permanent(void);
 427int tracing_is_on(void);
 428#else
 429static inline void tracing_on(void) { }
 430static inline void tracing_off(void) { }
 431static inline void tracing_off_permanent(void) { }
 432static inline int tracing_is_on(void) { return 0; }
 433#endif
 434#ifdef CONFIG_TRACING
 435extern void tracing_start(void);
 436extern void tracing_stop(void);
 437extern void ftrace_off_permanent(void);
 438
 439extern void
 440ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 441
 442static inline void __attribute__ ((format (printf, 1, 2)))
 443____trace_printk_check_format(const char *fmt, ...)
 444{
 445}
 446#define __trace_printk_check_format(fmt, args...)                       \
 447do {                                                                    \
 448        if (0)                                                          \
 449                ____trace_printk_check_format(fmt, ##args);             \
 450} while (0)
 451
 452/**
 453 * trace_printk - printf formatting in the ftrace buffer
 454 * @fmt: the printf format for printing
 455 *
 456 * Note: __trace_printk is an internal function for trace_printk and
 457 *       the @ip is passed in via the trace_printk macro.
 458 *
 459 * This function allows a kernel developer to debug fast path sections
 460 * that printk is not appropriate for. By scattering in various
 461 * printk like tracing in the code, a developer can quickly see
 462 * where problems are occurring.
 463 *
 464 * This is intended as a debugging tool for the developer only.
 465 * Please refrain from leaving trace_printks scattered around in
 466 * your code.
 467 */
 468
 469#define trace_printk(fmt, args...)                                      \
 470do {                                                                    \
 471        __trace_printk_check_format(fmt, ##args);                       \
 472        if (__builtin_constant_p(fmt)) {                                \
 473                static const char *trace_printk_fmt                     \
 474                  __attribute__((section("__trace_printk_fmt"))) =      \
 475                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 476                                                                        \
 477                __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 478        } else                                                          \
 479                __trace_printk(_THIS_IP_, fmt, ##args);         \
 480} while (0)
 481
 482extern int
 483__trace_bprintk(unsigned long ip, const char *fmt, ...)
 484        __attribute__ ((format (printf, 2, 3)));
 485
 486extern int
 487__trace_printk(unsigned long ip, const char *fmt, ...)
 488        __attribute__ ((format (printf, 2, 3)));
 489
 490/*
 491 * The double __builtin_constant_p is because gcc will give us an error
 492 * if we try to allocate the static variable to fmt if it is not a
 493 * constant. Even with the outer if statement.
 494 */
 495#define ftrace_vprintk(fmt, vargs)                                      \
 496do {                                                                    \
 497        if (__builtin_constant_p(fmt)) {                                \
 498                static const char *trace_printk_fmt                     \
 499                  __attribute__((section("__trace_printk_fmt"))) =      \
 500                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 501                                                                        \
 502                __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 503        } else                                                          \
 504                __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 505} while (0)
 506
 507extern int
 508__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 509
 510extern int
 511__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 512
 513extern void ftrace_dump(void);
 514#else
 515static inline void
 516ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 517static inline int
 518trace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
 519
 520static inline void tracing_start(void) { }
 521static inline void tracing_stop(void) { }
 522static inline void ftrace_off_permanent(void) { }
 523static inline int
 524trace_printk(const char *fmt, ...)
 525{
 526        return 0;
 527}
 528static inline int
 529ftrace_vprintk(const char *fmt, va_list ap)
 530{
 531        return 0;
 532}
 533static inline void ftrace_dump(void) { }
 534#endif /* CONFIG_TRACING */
 535
 536/*
 537 *      Display an IP address in readable format.
 538 */
 539
 540#define NIPQUAD(addr) \
 541        ((unsigned char *)&addr)[0], \
 542        ((unsigned char *)&addr)[1], \
 543        ((unsigned char *)&addr)[2], \
 544        ((unsigned char *)&addr)[3]
 545#define NIPQUAD_FMT "%u.%u.%u.%u"
 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/**
 565 * clamp - return a value clamped to a given range with strict typechecking
 566 * @val: current value
 567 * @min: minimum allowable value
 568 * @max: maximum allowable value
 569 *
 570 * This macro does strict typechecking of min/max to make sure they are of the
 571 * same type as val.  See the unnecessary pointer comparisons.
 572 */
 573#define clamp(val, min, max) ({                 \
 574        typeof(val) __val = (val);              \
 575        typeof(min) __min = (min);              \
 576        typeof(max) __max = (max);              \
 577        (void) (&__val == &__min);              \
 578        (void) (&__val == &__max);              \
 579        __val = __val < __min ? __min: __val;   \
 580        __val > __max ? __max: __val; })
 581
 582/*
 583 * ..and if you can't take the strict
 584 * types, you can specify one yourself.
 585 *
 586 * Or not use min/max/clamp at all, of course.
 587 */
 588#define min_t(type, x, y) ({                    \
 589        type __min1 = (x);                      \
 590        type __min2 = (y);                      \
 591        __min1 < __min2 ? __min1: __min2; })
 592
 593#define max_t(type, x, y) ({                    \
 594        type __max1 = (x);                      \
 595        type __max2 = (y);                      \
 596        __max1 > __max2 ? __max1: __max2; })
 597
 598/**
 599 * clamp_t - return a value clamped to a given range using a given type
 600 * @type: the type of variable to use
 601 * @val: current value
 602 * @min: minimum allowable value
 603 * @max: maximum allowable value
 604 *
 605 * This macro does no typechecking and uses temporary variables of type
 606 * 'type' to make all the comparisons.
 607 */
 608#define clamp_t(type, val, min, max) ({         \
 609        type __val = (val);                     \
 610        type __min = (min);                     \
 611        type __max = (max);                     \
 612        __val = __val < __min ? __min: __val;   \
 613        __val > __max ? __max: __val; })
 614
 615/**
 616 * clamp_val - return a value clamped to a given range using val's type
 617 * @val: current value
 618 * @min: minimum allowable value
 619 * @max: maximum allowable value
 620 *
 621 * This macro does no typechecking and uses temporary variables of whatever
 622 * type the input argument 'val' is.  This is useful when val is an unsigned
 623 * type and min and max are literals that will otherwise be assigned a signed
 624 * integer type.
 625 */
 626#define clamp_val(val, min, max) ({             \
 627        typeof(val) __val = (val);              \
 628        typeof(val) __min = (min);              \
 629        typeof(val) __max = (max);              \
 630        __val = __val < __min ? __min: __val;   \
 631        __val > __max ? __max: __val; })
 632
 633
 634/*
 635 * swap - swap value of @a and @b
 636 */
 637#define swap(a, b) \
 638        do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 639
 640/**
 641 * container_of - cast a member of a structure out to the containing structure
 642 * @ptr:        the pointer to the member.
 643 * @type:       the type of the container struct this is embedded in.
 644 * @member:     the name of the member within the struct.
 645 *
 646 */
 647#define container_of(ptr, type, member) ({                      \
 648        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 649        (type *)( (char *)__mptr - offsetof(type,member) );})
 650
 651struct sysinfo;
 652extern int do_sysinfo(struct sysinfo *info);
 653
 654#endif /* __KERNEL__ */
 655
 656#define SI_LOAD_SHIFT   16
 657struct sysinfo {
 658        long uptime;                    /* Seconds since boot */
 659        unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 660        unsigned long totalram;         /* Total usable main memory size */
 661        unsigned long freeram;          /* Available memory size */
 662        unsigned long sharedram;        /* Amount of shared memory */
 663        unsigned long bufferram;        /* Memory used by buffers */
 664        unsigned long totalswap;        /* Total swap space size */
 665        unsigned long freeswap;         /* swap space still available */
 666        unsigned short procs;           /* Number of current processes */
 667        unsigned short pad;             /* explicit padding for m68k */
 668        unsigned long totalhigh;        /* Total high memory size */
 669        unsigned long freehigh;         /* Available high memory size */
 670        unsigned int mem_unit;          /* Memory unit size in bytes */
 671        char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 672};
 673
 674/* Force a compilation error if condition is true */
 675#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 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(char[1 - 2 * !!(e)]) - 1)
 682
 683/* Trap pasters of __FUNCTION__ at compile-time */
 684#define __FUNCTION__ (__func__)
 685
 686/* This helps us to avoid #ifdef CONFIG_NUMA */
 687#ifdef CONFIG_NUMA
 688#define NUMA_BUILD 1
 689#else
 690#define NUMA_BUILD 0
 691#endif
 692
 693/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 694#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 695# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 696#endif
 697
 698#endif
 699
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