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_LBDAF
  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/* Use the default kernel loglevel */
 101#define KERN_DEFAULT    "<d>"
 102/*
 103 * Annotation for a "continued" line of log printout (only done after a
 104 * line that had no enclosing \n). Only to be used by core/arch code
 105 * during early bootup (a continued line is not SMP-safe otherwise).
 106 */
 107#define KERN_CONT       "<c>"
 108
 109extern int console_printk[];
 110
 111#define console_loglevel (console_printk[0])
 112#define default_message_loglevel (console_printk[1])
 113#define minimum_console_loglevel (console_printk[2])
 114#define default_console_loglevel (console_printk[3])
 115
 116struct completion;
 117struct pt_regs;
 118struct user;
 119
 120#ifdef CONFIG_PREEMPT_VOLUNTARY
 121extern int _cond_resched(void);
 122# define might_resched() _cond_resched()
 123#else
 124# define might_resched() do { } while (0)
 125#endif
 126
 127#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
 128  void __might_sleep(char *file, int line);
 129/**
 130 * might_sleep - annotation for functions that can sleep
 131 *
 132 * this macro will print a stack trace if it is executed in an atomic
 133 * context (spinlock, irq-handler, ...).
 134 *
 135 * This is a useful debugging help to be able to catch problems early and not
 136 * be bitten later when the calling function happens to sleep when it is not
 137 * supposed to.
 138 */
 139# define might_sleep() \
 140        do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0)
 141#else
 142# define might_sleep() do { might_resched(); } while (0)
 143#endif
 144
 145#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 146
 147#define abs(x) ({                               \
 148                int __x = (x);                  \
 149                (__x < 0) ? -__x : __x;         \
 150        })
 151
 152#ifdef CONFIG_PROVE_LOCKING
 153void might_fault(void);
 154#else
 155static inline void might_fault(void)
 156{
 157        might_sleep();
 158}
 159#endif
 160
 161extern struct atomic_notifier_head panic_notifier_list;
 162extern long (*panic_blink)(long time);
 163NORET_TYPE void panic(const char * fmt, ...)
 164        __attribute__ ((NORET_AND format (printf, 1, 2))) __cold;
 165extern void oops_enter(void);
 166extern void oops_exit(void);
 167extern int oops_may_print(void);
 168NORET_TYPE void do_exit(long error_code)
 169        ATTRIB_NORET;
 170NORET_TYPE void complete_and_exit(struct completion *, long)
 171        ATTRIB_NORET;
 172extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 173extern long simple_strtol(const char *,char **,unsigned int);
 174extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 175extern long long simple_strtoll(const char *,char **,unsigned int);
 176extern int strict_strtoul(const char *, unsigned int, unsigned long *);
 177extern int strict_strtol(const char *, unsigned int, long *);
 178extern int strict_strtoull(const char *, unsigned int, unsigned long long *);
 179extern int strict_strtoll(const char *, unsigned int, long long *);
 180extern int sprintf(char * buf, const char * fmt, ...)
 181        __attribute__ ((format (printf, 2, 3)));
 182extern int vsprintf(char *buf, const char *, va_list)
 183        __attribute__ ((format (printf, 2, 0)));
 184extern int snprintf(char * buf, size_t size, const char * fmt, ...)
 185        __attribute__ ((format (printf, 3, 4)));
 186extern int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
 187        __attribute__ ((format (printf, 3, 0)));
 188extern int scnprintf(char * buf, size_t size, const char * fmt, ...)
 189        __attribute__ ((format (printf, 3, 4)));
 190extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
 191        __attribute__ ((format (printf, 3, 0)));
 192extern char *kasprintf(gfp_t gfp, const char *fmt, ...)
 193        __attribute__ ((format (printf, 2, 3)));
 194extern char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 195
 196extern int sscanf(const char *, const char *, ...)
 197        __attribute__ ((format (scanf, 2, 3)));
 198extern int vsscanf(const char *, const char *, va_list)
 199        __attribute__ ((format (scanf, 2, 0)));
 200
 201extern int get_option(char **str, int *pint);
 202extern char *get_options(const char *str, int nints, int *ints);
 203extern unsigned long long memparse(const char *ptr, char **retptr);
 204
 205extern int core_kernel_text(unsigned long addr);
 206extern int __kernel_text_address(unsigned long addr);
 207extern int kernel_text_address(unsigned long addr);
 208extern int func_ptr_is_kernel_text(void *ptr);
 209
 210struct pid;
 211extern struct pid *session_of_pgrp(struct pid *pgrp);
 212
 213/*
 214 * FW_BUG
 215 * Add this to a message where you are sure the firmware is buggy or behaves
 216 * really stupid or out of spec. Be aware that the responsible BIOS developer
 217 * should be able to fix this issue or at least get a concrete idea of the
 218 * problem by reading your message without the need of looking at the kernel
 219 * code.
 220 * 
 221 * Use it for definite and high priority BIOS bugs.
 222 *
 223 * FW_WARN
 224 * Use it for not that clear (e.g. could the kernel messed up things already?)
 225 * and medium priority BIOS bugs.
 226 *
 227 * FW_INFO
 228 * Use this one if you want to tell the user or vendor about something
 229 * suspicious, but generally harmless related to the firmware.
 230 *
 231 * Use it for information or very low priority BIOS bugs.
 232 */
 233#define FW_BUG          "[Firmware Bug]: "
 234#define FW_WARN         "[Firmware Warn]: "
 235#define FW_INFO         "[Firmware Info]: "
 236
 237#ifdef CONFIG_PRINTK
 238asmlinkage int vprintk(const char *fmt, va_list args)
 239        __attribute__ ((format (printf, 1, 0)));
 240asmlinkage int printk(const char * fmt, ...)
 241        __attribute__ ((format (printf, 1, 2))) __cold;
 242
 243extern struct ratelimit_state printk_ratelimit_state;
 244extern int printk_ratelimit(void);
 245extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 246                                   unsigned int interval_msec);
 247
 248/*
 249 * Print a one-time message (analogous to WARN_ONCE() et al):
 250 */
 251#define printk_once(x...) ({                    \
 252        static int __print_once = 1;            \
 253                                                \
 254        if (__print_once) {                     \
 255                __print_once = 0;               \
 256                printk(x);                      \
 257        }                                       \
 258})
 259
 260void log_buf_kexec_setup(void);
 261#else
 262static inline int vprintk(const char *s, va_list args)
 263        __attribute__ ((format (printf, 1, 0)));
 264static inline int vprintk(const char *s, va_list args) { return 0; }
 265static inline int printk(const char *s, ...)
 266        __attribute__ ((format (printf, 1, 2)));
 267static inline int __cold printk(const char *s, ...) { return 0; }
 268static inline int printk_ratelimit(void) { return 0; }
 269static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies, \
 270                                          unsigned int interval_msec)   \
 271                { return false; }
 272
 273/* No effect, but we still get type checking even in the !PRINTK case: */
 274#define printk_once(x...) printk(x)
 275
 276static inline void log_buf_kexec_setup(void)
 277{
 278}
 279#endif
 280
 281extern int printk_needs_cpu(int cpu);
 282extern void printk_tick(void);
 283
 284extern void asmlinkage __attribute__((format(printf, 1, 2)))
 285        early_printk(const char *fmt, ...);
 286
 287unsigned long int_sqrt(unsigned long);
 288
 289static inline void console_silent(void)
 290{
 291        console_loglevel = 0;
 292}
 293
 294static inline void console_verbose(void)
 295{
 296        if (console_loglevel)
 297                console_loglevel = 15;
 298}
 299
 300extern void bust_spinlocks(int yes);
 301extern void wake_up_klogd(void);
 302extern int oops_in_progress;            /* If set, an oops, panic(), BUG() or die() is in progress */
 303extern int panic_timeout;
 304extern int panic_on_oops;
 305extern int panic_on_unrecovered_nmi;
 306extern int panic_on_io_nmi;
 307extern const char *print_tainted(void);
 308extern void add_taint(unsigned flag);
 309extern int test_taint(unsigned flag);
 310extern unsigned long get_taint(void);
 311extern int root_mountflags;
 312
 313/* Values used for system_state */
 314extern enum system_states {
 315        SYSTEM_BOOTING,
 316        SYSTEM_RUNNING,
 317        SYSTEM_HALT,
 318        SYSTEM_POWER_OFF,
 319        SYSTEM_RESTART,
 320        SYSTEM_SUSPEND_DISK,
 321} system_state;
 322
 323#define TAINT_PROPRIETARY_MODULE        0
 324#define TAINT_FORCED_MODULE             1
 325#define TAINT_UNSAFE_SMP                2
 326#define TAINT_FORCED_RMMOD              3
 327#define TAINT_MACHINE_CHECK             4
 328#define TAINT_BAD_PAGE                  5
 329#define TAINT_USER                      6
 330#define TAINT_DIE                       7
 331#define TAINT_OVERRIDDEN_ACPI_TABLE     8
 332#define TAINT_WARN                      9
 333#define TAINT_CRAP                      10
 334
 335extern void dump_stack(void) __cold;
 336
 337enum {
 338        DUMP_PREFIX_NONE,
 339        DUMP_PREFIX_ADDRESS,
 340        DUMP_PREFIX_OFFSET
 341};
 342extern void hex_dump_to_buffer(const void *buf, size_t len,
 343                                int rowsize, int groupsize,
 344                                char *linebuf, size_t linebuflen, bool ascii);
 345extern void print_hex_dump(const char *level, const char *prefix_str,
 346                                int prefix_type, int rowsize, int groupsize,
 347                                const void *buf, size_t len, bool ascii);
 348extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
 349                        const void *buf, size_t len);
 350
 351extern const char hex_asc[];
 352#define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 353#define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 354
 355static inline char *pack_hex_byte(char *buf, u8 byte)
 356{
 357        *buf++ = hex_asc_hi(byte);
 358        *buf++ = hex_asc_lo(byte);
 359        return buf;
 360}
 361
 362#ifndef pr_fmt
 363#define pr_fmt(fmt) fmt
 364#endif
 365
 366#define pr_emerg(fmt, ...) \
 367        printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
 368#define pr_alert(fmt, ...) \
 369        printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
 370#define pr_crit(fmt, ...) \
 371        printk(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
 372#define pr_err(fmt, ...) \
 373        printk(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
 374#define pr_warning(fmt, ...) \
 375        printk(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
 376#define pr_notice(fmt, ...) \
 377        printk(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
 378#define pr_info(fmt, ...) \
 379        printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
 380#define pr_cont(fmt, ...) \
 381        printk(KERN_CONT fmt, ##__VA_ARGS__)
 382
 383/* pr_devel() should produce zero code unless DEBUG is defined */
 384#ifdef DEBUG
 385#define pr_devel(fmt, ...) \
 386        printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 387#else
 388#define pr_devel(fmt, ...) \
 389        ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; })
 390#endif
 391
 392/* If you are writing a driver, please use dev_dbg instead */
 393#if defined(DEBUG)
 394#define pr_debug(fmt, ...) \
 395        printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
 396#elif defined(CONFIG_DYNAMIC_DEBUG)
 397/* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */
 398#define pr_debug(fmt, ...) do { \
 399        dynamic_pr_debug(fmt, ##__VA_ARGS__); \
 400        } while (0)
 401#else
 402#define pr_debug(fmt, ...) \
 403        ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; })
 404#endif
 405
 406/*
 407 * General tracing related utility functions - trace_printk(),
 408 * tracing_on/tracing_off and tracing_start()/tracing_stop
 409 *
 410 * Use tracing_on/tracing_off when you want to quickly turn on or off
 411 * tracing. It simply enables or disables the recording of the trace events.
 412 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 413 * file, which gives a means for the kernel and userspace to interact.
 414 * Place a tracing_off() in the kernel where you want tracing to end.
 415 * From user space, examine the trace, and then echo 1 > tracing_on
 416 * to continue tracing.
 417 *
 418 * tracing_stop/tracing_start has slightly more overhead. It is used
 419 * by things like suspend to ram where disabling the recording of the
 420 * trace is not enough, but tracing must actually stop because things
 421 * like calling smp_processor_id() may crash the system.
 422 *
 423 * Most likely, you want to use tracing_on/tracing_off.
 424 */
 425#ifdef CONFIG_RING_BUFFER
 426void tracing_on(void);
 427void tracing_off(void);
 428/* trace_off_permanent stops recording with no way to bring it back */
 429void tracing_off_permanent(void);
 430int tracing_is_on(void);
 431#else
 432static inline void tracing_on(void) { }
 433static inline void tracing_off(void) { }
 434static inline void tracing_off_permanent(void) { }
 435static inline int tracing_is_on(void) { return 0; }
 436#endif
 437#ifdef CONFIG_TRACING
 438extern void tracing_start(void);
 439extern void tracing_stop(void);
 440extern void ftrace_off_permanent(void);
 441
 442extern void
 443ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 444
 445static inline void __attribute__ ((format (printf, 1, 2)))
 446____trace_printk_check_format(const char *fmt, ...)
 447{
 448}
 449#define __trace_printk_check_format(fmt, args...)                       \
 450do {                                                                    \
 451        if (0)                                                          \
 452                ____trace_printk_check_format(fmt, ##args);             \
 453} while (0)
 454
 455/**
 456 * trace_printk - printf formatting in the ftrace buffer
 457 * @fmt: the printf format for printing
 458 *
 459 * Note: __trace_printk is an internal function for trace_printk and
 460 *       the @ip is passed in via the trace_printk macro.
 461 *
 462 * This function allows a kernel developer to debug fast path sections
 463 * that printk is not appropriate for. By scattering in various
 464 * printk like tracing in the code, a developer can quickly see
 465 * where problems are occurring.
 466 *
 467 * This is intended as a debugging tool for the developer only.
 468 * Please refrain from leaving trace_printks scattered around in
 469 * your code.
 470 */
 471
 472#define trace_printk(fmt, args...)                                      \
 473do {                                                                    \
 474        __trace_printk_check_format(fmt, ##args);                       \
 475        if (__builtin_constant_p(fmt)) {                                \
 476                static const char *trace_printk_fmt                     \
 477                  __attribute__((section("__trace_printk_fmt"))) =      \
 478                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 479                                                                        \
 480                __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 481        } else                                                          \
 482                __trace_printk(_THIS_IP_, fmt, ##args);         \
 483} while (0)
 484
 485extern int
 486__trace_bprintk(unsigned long ip, const char *fmt, ...)
 487        __attribute__ ((format (printf, 2, 3)));
 488
 489extern int
 490__trace_printk(unsigned long ip, const char *fmt, ...)
 491        __attribute__ ((format (printf, 2, 3)));
 492
 493/*
 494 * The double __builtin_constant_p is because gcc will give us an error
 495 * if we try to allocate the static variable to fmt if it is not a
 496 * constant. Even with the outer if statement.
 497 */
 498#define ftrace_vprintk(fmt, vargs)                                      \
 499do {                                                                    \
 500        if (__builtin_constant_p(fmt)) {                                \
 501                static const char *trace_printk_fmt                     \
 502                  __attribute__((section("__trace_printk_fmt"))) =      \
 503                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 504                                                                        \
 505                __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 506        } else                                                          \
 507                __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 508} while (0)
 509
 510extern int
 511__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 512
 513extern int
 514__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 515
 516extern void ftrace_dump(void);
 517#else
 518static inline void
 519ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 520static inline int
 521trace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
 522
 523static inline void tracing_start(void) { }
 524static inline void tracing_stop(void) { }
 525static inline void ftrace_off_permanent(void) { }
 526static inline int
 527trace_printk(const char *fmt, ...)
 528{
 529        return 0;
 530}
 531static inline int
 532ftrace_vprintk(const char *fmt, va_list ap)
 533{
 534        return 0;
 535}
 536static inline void ftrace_dump(void) { }
 537#endif /* CONFIG_TRACING */
 538
 539/*
 540 *      Display an IP address in readable format.
 541 */
 542
 543#define NIPQUAD(addr) \
 544        ((unsigned char *)&addr)[0], \
 545        ((unsigned char *)&addr)[1], \
 546        ((unsigned char *)&addr)[2], \
 547        ((unsigned char *)&addr)[3]
 548#define NIPQUAD_FMT "%u.%u.%u.%u"
 549
 550/*
 551 * min()/max()/clamp() macros that also do
 552 * strict type-checking.. See the
 553 * "unnecessary" pointer comparison.
 554 */
 555#define min(x, y) ({                            \
 556        typeof(x) _min1 = (x);                  \
 557        typeof(y) _min2 = (y);                  \
 558        (void) (&_min1 == &_min2);              \
 559        _min1 < _min2 ? _min1 : _min2; })
 560
 561#define max(x, y) ({                            \
 562        typeof(x) _max1 = (x);                  \
 563        typeof(y) _max2 = (y);                  \
 564        (void) (&_max1 == &_max2);              \
 565        _max1 > _max2 ? _max1 : _max2; })
 566
 567/**
 568 * clamp - return a value clamped to a given range with strict typechecking
 569 * @val: current value
 570 * @min: minimum allowable value
 571 * @max: maximum allowable value
 572 *
 573 * This macro does strict typechecking of min/max to make sure they are of the
 574 * same type as val.  See the unnecessary pointer comparisons.
 575 */
 576#define clamp(val, min, max) ({                 \
 577        typeof(val) __val = (val);              \
 578        typeof(min) __min = (min);              \
 579        typeof(max) __max = (max);              \
 580        (void) (&__val == &__min);              \
 581        (void) (&__val == &__max);              \
 582        __val = __val < __min ? __min: __val;   \
 583        __val > __max ? __max: __val; })
 584
 585/*
 586 * ..and if you can't take the strict
 587 * types, you can specify one yourself.
 588 *
 589 * Or not use min/max/clamp at all, of course.
 590 */
 591#define min_t(type, x, y) ({                    \
 592        type __min1 = (x);                      \
 593        type __min2 = (y);                      \
 594        __min1 < __min2 ? __min1: __min2; })
 595
 596#define max_t(type, x, y) ({                    \
 597        type __max1 = (x);                      \
 598        type __max2 = (y);                      \
 599        __max1 > __max2 ? __max1: __max2; })
 600
 601/**
 602 * clamp_t - return a value clamped to a given range using a given type
 603 * @type: the type of variable to use
 604 * @val: current value
 605 * @min: minimum allowable value
 606 * @max: maximum allowable value
 607 *
 608 * This macro does no typechecking and uses temporary variables of type
 609 * 'type' to make all the comparisons.
 610 */
 611#define clamp_t(type, val, min, max) ({         \
 612        type __val = (val);                     \
 613        type __min = (min);                     \
 614        type __max = (max);                     \
 615        __val = __val < __min ? __min: __val;   \
 616        __val > __max ? __max: __val; })
 617
 618/**
 619 * clamp_val - return a value clamped to a given range using val's type
 620 * @val: current value
 621 * @min: minimum allowable value
 622 * @max: maximum allowable value
 623 *
 624 * This macro does no typechecking and uses temporary variables of whatever
 625 * type the input argument 'val' is.  This is useful when val is an unsigned
 626 * type and min and max are literals that will otherwise be assigned a signed
 627 * integer type.
 628 */
 629#define clamp_val(val, min, max) ({             \
 630        typeof(val) __val = (val);              \
 631        typeof(val) __min = (min);              \
 632        typeof(val) __max = (max);              \
 633        __val = __val < __min ? __min: __val;   \
 634        __val > __max ? __max: __val; })
 635
 636
 637/*
 638 * swap - swap value of @a and @b
 639 */
 640#define swap(a, b) \
 641        do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 642
 643/**
 644 * container_of - cast a member of a structure out to the containing structure
 645 * @ptr:        the pointer to the member.
 646 * @type:       the type of the container struct this is embedded in.
 647 * @member:     the name of the member within the struct.
 648 *
 649 */
 650#define container_of(ptr, type, member) ({                      \
 651        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 652        (type *)( (char *)__mptr - offsetof(type,member) );})
 653
 654struct sysinfo;
 655extern int do_sysinfo(struct sysinfo *info);
 656
 657#endif /* __KERNEL__ */
 658
 659#define SI_LOAD_SHIFT   16
 660struct sysinfo {
 661        long uptime;                    /* Seconds since boot */
 662        unsigned long loads[3];         /* 1, 5, and 15 minute load averages */
 663        unsigned long totalram;         /* Total usable main memory size */
 664        unsigned long freeram;          /* Available memory size */
 665        unsigned long sharedram;        /* Amount of shared memory */
 666        unsigned long bufferram;        /* Memory used by buffers */
 667        unsigned long totalswap;        /* Total swap space size */
 668        unsigned long freeswap;         /* swap space still available */
 669        unsigned short procs;           /* Number of current processes */
 670        unsigned short pad;             /* explicit padding for m68k */
 671        unsigned long totalhigh;        /* Total high memory size */
 672        unsigned long freehigh;         /* Available high memory size */
 673        unsigned int mem_unit;          /* Memory unit size in bytes */
 674        char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding: libc5 uses this.. */
 675};
 676
 677/* Force a compilation error if condition is true */
 678#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
 679
 680/* Force a compilation error if condition is true, but also produce a
 681   result (of value 0 and type size_t), so the expression can be used
 682   e.g. in a structure initializer (or where-ever else comma expressions
 683   aren't permitted). */
 684#define BUILD_BUG_ON_ZERO(e) (sizeof(char[1 - 2 * !!(e)]) - 1)
 685
 686/* Trap pasters of __FUNCTION__ at compile-time */
 687#define __FUNCTION__ (__func__)
 688
 689/* This helps us to avoid #ifdef CONFIG_NUMA */
 690#ifdef CONFIG_NUMA
 691#define NUMA_BUILD 1
 692#else
 693#define NUMA_BUILD 0
 694#endif
 695
 696/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 697#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 698# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 699#endif
 700
 701#endif
 702
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