linux/include/linux/kernel.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_KERNEL_H
   3#define _LINUX_KERNEL_H
   4
   5#include <stdarg.h>
   6#include <linux/limits.h>
   7#include <linux/linkage.h>
   8#include <linux/stddef.h>
   9#include <linux/types.h>
  10#include <linux/compiler.h>
  11#include <linux/bitops.h>
  12#include <linux/log2.h>
  13#include <linux/math.h>
  14#include <linux/minmax.h>
  15#include <linux/typecheck.h>
  16#include <linux/printk.h>
  17#include <linux/build_bug.h>
  18
  19#include <asm/byteorder.h>
  20
  21#include <uapi/linux/kernel.h>
  22
  23#define STACK_MAGIC     0xdeadbeef
  24
  25/**
  26 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
  27 * @x: value to repeat
  28 *
  29 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
  30 */
  31#define REPEAT_BYTE(x)  ((~0ul / 0xff) * (x))
  32
  33/* @a is a power of 2 value */
  34#define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
  35#define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
  36#define __ALIGN_MASK(x, mask)   __ALIGN_KERNEL_MASK((x), (mask))
  37#define PTR_ALIGN(p, a)         ((typeof(p))ALIGN((unsigned long)(p), (a)))
  38#define PTR_ALIGN_DOWN(p, a)    ((typeof(p))ALIGN_DOWN((unsigned long)(p), (a)))
  39#define IS_ALIGNED(x, a)                (((x) & ((typeof(x))(a) - 1)) == 0)
  40
  41/* generic data direction definitions */
  42#define READ                    0
  43#define WRITE                   1
  44
  45/**
  46 * ARRAY_SIZE - get the number of elements in array @arr
  47 * @arr: array to be sized
  48 */
  49#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  50
  51#define u64_to_user_ptr(x) (            \
  52{                                       \
  53        typecheck(u64, (x));            \
  54        (void __user *)(uintptr_t)(x);  \
  55}                                       \
  56)
  57
  58#define typeof_member(T, m)     typeof(((T*)0)->m)
  59
  60#define _RET_IP_                (unsigned long)__builtin_return_address(0)
  61#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
  62
  63/**
  64 * upper_32_bits - return bits 32-63 of a number
  65 * @n: the number we're accessing
  66 *
  67 * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
  68 * the "right shift count >= width of type" warning when that quantity is
  69 * 32-bits.
  70 */
  71#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
  72
  73/**
  74 * lower_32_bits - return bits 0-31 of a number
  75 * @n: the number we're accessing
  76 */
  77#define lower_32_bits(n) ((u32)((n) & 0xffffffff))
  78
  79struct completion;
  80struct pt_regs;
  81struct user;
  82
  83#ifdef CONFIG_PREEMPT_VOLUNTARY
  84extern int _cond_resched(void);
  85# define might_resched() _cond_resched()
  86#else
  87# define might_resched() do { } while (0)
  88#endif
  89
  90#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
  91extern void ___might_sleep(const char *file, int line, int preempt_offset);
  92extern void __might_sleep(const char *file, int line, int preempt_offset);
  93extern void __cant_sleep(const char *file, int line, int preempt_offset);
  94extern void __cant_migrate(const char *file, int line);
  95
  96/**
  97 * might_sleep - annotation for functions that can sleep
  98 *
  99 * this macro will print a stack trace if it is executed in an atomic
 100 * context (spinlock, irq-handler, ...). Additional sections where blocking is
 101 * not allowed can be annotated with non_block_start() and non_block_end()
 102 * pairs.
 103 *
 104 * This is a useful debugging help to be able to catch problems early and not
 105 * be bitten later when the calling function happens to sleep when it is not
 106 * supposed to.
 107 */
 108# define might_sleep() \
 109        do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 110/**
 111 * cant_sleep - annotation for functions that cannot sleep
 112 *
 113 * this macro will print a stack trace if it is executed with preemption enabled
 114 */
 115# define cant_sleep() \
 116        do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
 117# define sched_annotate_sleep() (current->task_state_change = 0)
 118
 119/**
 120 * cant_migrate - annotation for functions that cannot migrate
 121 *
 122 * Will print a stack trace if executed in code which is migratable
 123 */
 124# define cant_migrate()                                                 \
 125        do {                                                            \
 126                if (IS_ENABLED(CONFIG_SMP))                             \
 127                        __cant_migrate(__FILE__, __LINE__);             \
 128        } while (0)
 129
 130/**
 131 * non_block_start - annotate the start of section where sleeping is prohibited
 132 *
 133 * This is on behalf of the oom reaper, specifically when it is calling the mmu
 134 * notifiers. The problem is that if the notifier were to block on, for example,
 135 * mutex_lock() and if the process which holds that mutex were to perform a
 136 * sleeping memory allocation, the oom reaper is now blocked on completion of
 137 * that memory allocation. Other blocking calls like wait_event() pose similar
 138 * issues.
 139 */
 140# define non_block_start() (current->non_block_count++)
 141/**
 142 * non_block_end - annotate the end of section where sleeping is prohibited
 143 *
 144 * Closes a section opened by non_block_start().
 145 */
 146# define non_block_end() WARN_ON(current->non_block_count-- == 0)
 147#else
 148  static inline void ___might_sleep(const char *file, int line,
 149                                   int preempt_offset) { }
 150  static inline void __might_sleep(const char *file, int line,
 151                                   int preempt_offset) { }
 152# define might_sleep() do { might_resched(); } while (0)
 153# define cant_sleep() do { } while (0)
 154# define cant_migrate()         do { } while (0)
 155# define sched_annotate_sleep() do { } while (0)
 156# define non_block_start() do { } while (0)
 157# define non_block_end() do { } while (0)
 158#endif
 159
 160#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 161
 162#if defined(CONFIG_MMU) && \
 163        (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
 164#define might_fault() __might_fault(__FILE__, __LINE__)
 165void __might_fault(const char *file, int line);
 166#else
 167static inline void might_fault(void) { }
 168#endif
 169
 170extern struct atomic_notifier_head panic_notifier_list;
 171extern long (*panic_blink)(int state);
 172__printf(1, 2)
 173void panic(const char *fmt, ...) __noreturn __cold;
 174void nmi_panic(struct pt_regs *regs, const char *msg);
 175extern void oops_enter(void);
 176extern void oops_exit(void);
 177extern bool oops_may_print(void);
 178void do_exit(long error_code) __noreturn;
 179void complete_and_exit(struct completion *, long) __noreturn;
 180
 181/* Internal, do not use. */
 182int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 183int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 184
 185int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 186int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 187
 188/**
 189 * kstrtoul - convert a string to an unsigned long
 190 * @s: The start of the string. The string must be null-terminated, and may also
 191 *  include a single newline before its terminating null. The first character
 192 *  may also be a plus sign, but not a minus sign.
 193 * @base: The number base to use. The maximum supported base is 16. If base is
 194 *  given as 0, then the base of the string is automatically detected with the
 195 *  conventional semantics - If it begins with 0x the number will be parsed as a
 196 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 197 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 198 * @res: Where to write the result of the conversion on success.
 199 *
 200 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 201 * Preferred over simple_strtoul(). Return code must be checked.
 202*/
 203static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 204{
 205        /*
 206         * We want to shortcut function call, but
 207         * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 208         */
 209        if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 210            __alignof__(unsigned long) == __alignof__(unsigned long long))
 211                return kstrtoull(s, base, (unsigned long long *)res);
 212        else
 213                return _kstrtoul(s, base, res);
 214}
 215
 216/**
 217 * kstrtol - convert a string to a long
 218 * @s: The start of the string. The string must be null-terminated, and may also
 219 *  include a single newline before its terminating null. The first character
 220 *  may also be a plus sign or a minus sign.
 221 * @base: The number base to use. The maximum supported base is 16. If base is
 222 *  given as 0, then the base of the string is automatically detected with the
 223 *  conventional semantics - If it begins with 0x the number will be parsed as a
 224 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 225 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 226 * @res: Where to write the result of the conversion on success.
 227 *
 228 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 229 * Preferred over simple_strtol(). Return code must be checked.
 230 */
 231static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 232{
 233        /*
 234         * We want to shortcut function call, but
 235         * __builtin_types_compatible_p(long, long long) = 0.
 236         */
 237        if (sizeof(long) == sizeof(long long) &&
 238            __alignof__(long) == __alignof__(long long))
 239                return kstrtoll(s, base, (long long *)res);
 240        else
 241                return _kstrtol(s, base, res);
 242}
 243
 244int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 245int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 246
 247static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 248{
 249        return kstrtoull(s, base, res);
 250}
 251
 252static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 253{
 254        return kstrtoll(s, base, res);
 255}
 256
 257static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 258{
 259        return kstrtouint(s, base, res);
 260}
 261
 262static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 263{
 264        return kstrtoint(s, base, res);
 265}
 266
 267int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 268int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 269int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 270int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 271int __must_check kstrtobool(const char *s, bool *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);
 283int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
 284
 285static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 286{
 287        return kstrtoull_from_user(s, count, base, res);
 288}
 289
 290static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 291{
 292        return kstrtoll_from_user(s, count, base, res);
 293}
 294
 295static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 296{
 297        return kstrtouint_from_user(s, count, base, res);
 298}
 299
 300static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 301{
 302        return kstrtoint_from_user(s, count, base, res);
 303}
 304
 305/*
 306 * Use kstrto<foo> instead.
 307 *
 308 * NOTE: simple_strto<foo> does not check for the range overflow and,
 309 *       depending on the input, may give interesting results.
 310 *
 311 * Use these functions if and only if you cannot use kstrto<foo>, because
 312 * the conversion ends on the first non-digit character, which may be far
 313 * beyond the supported range. It might be useful to parse the strings like
 314 * 10x50 or 12:21 without altering original string or temporary buffer in use.
 315 * Keep in mind above caveat.
 316 */
 317
 318extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 319extern long simple_strtol(const char *,char **,unsigned int);
 320extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 321extern long long simple_strtoll(const char *,char **,unsigned int);
 322
 323extern int num_to_str(char *buf, int size,
 324                      unsigned long long num, unsigned int width);
 325
 326/* lib/printf utilities */
 327
 328extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 329extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 330extern __printf(3, 4)
 331int snprintf(char *buf, size_t size, const char *fmt, ...);
 332extern __printf(3, 0)
 333int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 334extern __printf(3, 4)
 335int scnprintf(char *buf, size_t size, const char *fmt, ...);
 336extern __printf(3, 0)
 337int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 338extern __printf(2, 3) __malloc
 339char *kasprintf(gfp_t gfp, const char *fmt, ...);
 340extern __printf(2, 0) __malloc
 341char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 342extern __printf(2, 0)
 343const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
 344
 345extern __scanf(2, 3)
 346int sscanf(const char *, const char *, ...);
 347extern __scanf(2, 0)
 348int vsscanf(const char *, const char *, va_list);
 349
 350extern int get_option(char **str, int *pint);
 351extern char *get_options(const char *str, int nints, int *ints);
 352extern unsigned long long memparse(const char *ptr, char **retptr);
 353extern bool parse_option_str(const char *str, const char *option);
 354extern char *next_arg(char *args, char **param, char **val);
 355
 356extern int core_kernel_text(unsigned long addr);
 357extern int init_kernel_text(unsigned long addr);
 358extern int core_kernel_data(unsigned long addr);
 359extern int __kernel_text_address(unsigned long addr);
 360extern int kernel_text_address(unsigned long addr);
 361extern int func_ptr_is_kernel_text(void *ptr);
 362
 363#ifdef CONFIG_SMP
 364extern unsigned int sysctl_oops_all_cpu_backtrace;
 365#else
 366#define sysctl_oops_all_cpu_backtrace 0
 367#endif /* CONFIG_SMP */
 368
 369extern void bust_spinlocks(int yes);
 370extern int panic_timeout;
 371extern unsigned long panic_print;
 372extern int panic_on_oops;
 373extern int panic_on_unrecovered_nmi;
 374extern int panic_on_io_nmi;
 375extern int panic_on_warn;
 376extern unsigned long panic_on_taint;
 377extern bool panic_on_taint_nousertaint;
 378extern int sysctl_panic_on_rcu_stall;
 379extern int sysctl_max_rcu_stall_to_panic;
 380extern int sysctl_panic_on_stackoverflow;
 381
 382extern bool crash_kexec_post_notifiers;
 383
 384/*
 385 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
 386 * holds a CPU number which is executing panic() currently. A value of
 387 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
 388 */
 389extern atomic_t panic_cpu;
 390#define PANIC_CPU_INVALID       -1
 391
 392/*
 393 * Only to be used by arch init code. If the user over-wrote the default
 394 * CONFIG_PANIC_TIMEOUT, honor it.
 395 */
 396static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
 397{
 398        if (panic_timeout == arch_default_timeout)
 399                panic_timeout = timeout;
 400}
 401extern const char *print_tainted(void);
 402enum lockdep_ok {
 403        LOCKDEP_STILL_OK,
 404        LOCKDEP_NOW_UNRELIABLE
 405};
 406extern void add_taint(unsigned flag, enum lockdep_ok);
 407extern int test_taint(unsigned flag);
 408extern unsigned long get_taint(void);
 409extern int root_mountflags;
 410
 411extern bool early_boot_irqs_disabled;
 412
 413/*
 414 * Values used for system_state. Ordering of the states must not be changed
 415 * as code checks for <, <=, >, >= STATE.
 416 */
 417extern enum system_states {
 418        SYSTEM_BOOTING,
 419        SYSTEM_SCHEDULING,
 420        SYSTEM_RUNNING,
 421        SYSTEM_HALT,
 422        SYSTEM_POWER_OFF,
 423        SYSTEM_RESTART,
 424        SYSTEM_SUSPEND,
 425} system_state;
 426
 427/* This cannot be an enum because some may be used in assembly source. */
 428#define TAINT_PROPRIETARY_MODULE        0
 429#define TAINT_FORCED_MODULE             1
 430#define TAINT_CPU_OUT_OF_SPEC           2
 431#define TAINT_FORCED_RMMOD              3
 432#define TAINT_MACHINE_CHECK             4
 433#define TAINT_BAD_PAGE                  5
 434#define TAINT_USER                      6
 435#define TAINT_DIE                       7
 436#define TAINT_OVERRIDDEN_ACPI_TABLE     8
 437#define TAINT_WARN                      9
 438#define TAINT_CRAP                      10
 439#define TAINT_FIRMWARE_WORKAROUND       11
 440#define TAINT_OOT_MODULE                12
 441#define TAINT_UNSIGNED_MODULE           13
 442#define TAINT_SOFTLOCKUP                14
 443#define TAINT_LIVEPATCH                 15
 444#define TAINT_AUX                       16
 445#define TAINT_RANDSTRUCT                17
 446#define TAINT_FLAGS_COUNT               18
 447#define TAINT_FLAGS_MAX                 ((1UL << TAINT_FLAGS_COUNT) - 1)
 448
 449struct taint_flag {
 450        char c_true;    /* character printed when tainted */
 451        char c_false;   /* character printed when not tainted */
 452        bool module;    /* also show as a per-module taint flag */
 453};
 454
 455extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
 456
 457extern const char hex_asc[];
 458#define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 459#define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 460
 461static inline char *hex_byte_pack(char *buf, u8 byte)
 462{
 463        *buf++ = hex_asc_hi(byte);
 464        *buf++ = hex_asc_lo(byte);
 465        return buf;
 466}
 467
 468extern const char hex_asc_upper[];
 469#define hex_asc_upper_lo(x)     hex_asc_upper[((x) & 0x0f)]
 470#define hex_asc_upper_hi(x)     hex_asc_upper[((x) & 0xf0) >> 4]
 471
 472static inline char *hex_byte_pack_upper(char *buf, u8 byte)
 473{
 474        *buf++ = hex_asc_upper_hi(byte);
 475        *buf++ = hex_asc_upper_lo(byte);
 476        return buf;
 477}
 478
 479extern int hex_to_bin(char ch);
 480extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 481extern char *bin2hex(char *dst, const void *src, size_t count);
 482
 483bool mac_pton(const char *s, u8 *mac);
 484
 485/*
 486 * General tracing related utility functions - trace_printk(),
 487 * tracing_on/tracing_off and tracing_start()/tracing_stop
 488 *
 489 * Use tracing_on/tracing_off when you want to quickly turn on or off
 490 * tracing. It simply enables or disables the recording of the trace events.
 491 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 492 * file, which gives a means for the kernel and userspace to interact.
 493 * Place a tracing_off() in the kernel where you want tracing to end.
 494 * From user space, examine the trace, and then echo 1 > tracing_on
 495 * to continue tracing.
 496 *
 497 * tracing_stop/tracing_start has slightly more overhead. It is used
 498 * by things like suspend to ram where disabling the recording of the
 499 * trace is not enough, but tracing must actually stop because things
 500 * like calling smp_processor_id() may crash the system.
 501 *
 502 * Most likely, you want to use tracing_on/tracing_off.
 503 */
 504
 505enum ftrace_dump_mode {
 506        DUMP_NONE,
 507        DUMP_ALL,
 508        DUMP_ORIG,
 509};
 510
 511#ifdef CONFIG_TRACING
 512void tracing_on(void);
 513void tracing_off(void);
 514int tracing_is_on(void);
 515void tracing_snapshot(void);
 516void tracing_snapshot_alloc(void);
 517
 518extern void tracing_start(void);
 519extern void tracing_stop(void);
 520
 521static inline __printf(1, 2)
 522void ____trace_printk_check_format(const char *fmt, ...)
 523{
 524}
 525#define __trace_printk_check_format(fmt, args...)                       \
 526do {                                                                    \
 527        if (0)                                                          \
 528                ____trace_printk_check_format(fmt, ##args);             \
 529} while (0)
 530
 531/**
 532 * trace_printk - printf formatting in the ftrace buffer
 533 * @fmt: the printf format for printing
 534 *
 535 * Note: __trace_printk is an internal function for trace_printk() and
 536 *       the @ip is passed in via the trace_printk() macro.
 537 *
 538 * This function allows a kernel developer to debug fast path sections
 539 * that printk is not appropriate for. By scattering in various
 540 * printk like tracing in the code, a developer can quickly see
 541 * where problems are occurring.
 542 *
 543 * This is intended as a debugging tool for the developer only.
 544 * Please refrain from leaving trace_printks scattered around in
 545 * your code. (Extra memory is used for special buffers that are
 546 * allocated when trace_printk() is used.)
 547 *
 548 * A little optimization trick is done here. If there's only one
 549 * argument, there's no need to scan the string for printf formats.
 550 * The trace_puts() will suffice. But how can we take advantage of
 551 * using trace_puts() when trace_printk() has only one argument?
 552 * By stringifying the args and checking the size we can tell
 553 * whether or not there are args. __stringify((__VA_ARGS__)) will
 554 * turn into "()\0" with a size of 3 when there are no args, anything
 555 * else will be bigger. All we need to do is define a string to this,
 556 * and then take its size and compare to 3. If it's bigger, use
 557 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
 558 * let gcc optimize the rest.
 559 */
 560
 561#define trace_printk(fmt, ...)                          \
 562do {                                                    \
 563        char _______STR[] = __stringify((__VA_ARGS__)); \
 564        if (sizeof(_______STR) > 3)                     \
 565                do_trace_printk(fmt, ##__VA_ARGS__);    \
 566        else                                            \
 567                trace_puts(fmt);                        \
 568} while (0)
 569
 570#define do_trace_printk(fmt, args...)                                   \
 571do {                                                                    \
 572        static const char *trace_printk_fmt __used                      \
 573                __section("__trace_printk_fmt") =                       \
 574                __builtin_constant_p(fmt) ? fmt : NULL;                 \
 575                                                                        \
 576        __trace_printk_check_format(fmt, ##args);                       \
 577                                                                        \
 578        if (__builtin_constant_p(fmt))                                  \
 579                __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 580        else                                                            \
 581                __trace_printk(_THIS_IP_, fmt, ##args);                 \
 582} while (0)
 583
 584extern __printf(2, 3)
 585int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 586
 587extern __printf(2, 3)
 588int __trace_printk(unsigned long ip, const char *fmt, ...);
 589
 590/**
 591 * trace_puts - write a string into the ftrace buffer
 592 * @str: the string to record
 593 *
 594 * Note: __trace_bputs is an internal function for trace_puts and
 595 *       the @ip is passed in via the trace_puts macro.
 596 *
 597 * This is similar to trace_printk() but is made for those really fast
 598 * paths that a developer wants the least amount of "Heisenbug" effects,
 599 * where the processing of the print format is still too much.
 600 *
 601 * This function allows a kernel developer to debug fast path sections
 602 * that printk is not appropriate for. By scattering in various
 603 * printk like tracing in the code, a developer can quickly see
 604 * where problems are occurring.
 605 *
 606 * This is intended as a debugging tool for the developer only.
 607 * Please refrain from leaving trace_puts scattered around in
 608 * your code. (Extra memory is used for special buffers that are
 609 * allocated when trace_puts() is used.)
 610 *
 611 * Returns: 0 if nothing was written, positive # if string was.
 612 *  (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
 613 */
 614
 615#define trace_puts(str) ({                                              \
 616        static const char *trace_printk_fmt __used                      \
 617                __section("__trace_printk_fmt") =                       \
 618                __builtin_constant_p(str) ? str : NULL;                 \
 619                                                                        \
 620        if (__builtin_constant_p(str))                                  \
 621                __trace_bputs(_THIS_IP_, trace_printk_fmt);             \
 622        else                                                            \
 623                __trace_puts(_THIS_IP_, str, strlen(str));              \
 624})
 625extern int __trace_bputs(unsigned long ip, const char *str);
 626extern int __trace_puts(unsigned long ip, const char *str, int size);
 627
 628extern void trace_dump_stack(int skip);
 629
 630/*
 631 * The double __builtin_constant_p is because gcc will give us an error
 632 * if we try to allocate the static variable to fmt if it is not a
 633 * constant. Even with the outer if statement.
 634 */
 635#define ftrace_vprintk(fmt, vargs)                                      \
 636do {                                                                    \
 637        if (__builtin_constant_p(fmt)) {                                \
 638                static const char *trace_printk_fmt __used              \
 639                  __section("__trace_printk_fmt") =                     \
 640                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 641                                                                        \
 642                __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 643        } else                                                          \
 644                __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 645} while (0)
 646
 647extern __printf(2, 0) int
 648__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 649
 650extern __printf(2, 0) int
 651__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 652
 653extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 654#else
 655static inline void tracing_start(void) { }
 656static inline void tracing_stop(void) { }
 657static inline void trace_dump_stack(int skip) { }
 658
 659static inline void tracing_on(void) { }
 660static inline void tracing_off(void) { }
 661static inline int tracing_is_on(void) { return 0; }
 662static inline void tracing_snapshot(void) { }
 663static inline void tracing_snapshot_alloc(void) { }
 664
 665static inline __printf(1, 2)
 666int trace_printk(const char *fmt, ...)
 667{
 668        return 0;
 669}
 670static __printf(1, 0) inline int
 671ftrace_vprintk(const char *fmt, va_list ap)
 672{
 673        return 0;
 674}
 675static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 676#endif /* CONFIG_TRACING */
 677
 678/* This counts to 12. Any more, it will return 13th argument. */
 679#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
 680#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
 681
 682#define __CONCAT(a, b) a ## b
 683#define CONCATENATE(a, b) __CONCAT(a, b)
 684
 685/**
 686 * container_of - cast a member of a structure out to the containing structure
 687 * @ptr:        the pointer to the member.
 688 * @type:       the type of the container struct this is embedded in.
 689 * @member:     the name of the member within the struct.
 690 *
 691 */
 692#define container_of(ptr, type, member) ({                              \
 693        void *__mptr = (void *)(ptr);                                   \
 694        BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&   \
 695                         !__same_type(*(ptr), void),                    \
 696                         "pointer type mismatch in container_of()");    \
 697        ((type *)(__mptr - offsetof(type, member))); })
 698
 699/**
 700 * container_of_safe - cast a member of a structure out to the containing structure
 701 * @ptr:        the pointer to the member.
 702 * @type:       the type of the container struct this is embedded in.
 703 * @member:     the name of the member within the struct.
 704 *
 705 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
 706 */
 707#define container_of_safe(ptr, type, member) ({                         \
 708        void *__mptr = (void *)(ptr);                                   \
 709        BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&   \
 710                         !__same_type(*(ptr), void),                    \
 711                         "pointer type mismatch in container_of()");    \
 712        IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) :                     \
 713                ((type *)(__mptr - offsetof(type, member))); })
 714
 715/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 716#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 717# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 718#endif
 719
 720/* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
 721#define VERIFY_OCTAL_PERMISSIONS(perms)                                         \
 722        (BUILD_BUG_ON_ZERO((perms) < 0) +                                       \
 723         BUILD_BUG_ON_ZERO((perms) > 0777) +                                    \
 724         /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */                \
 725         BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) +       \
 726         BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) +              \
 727         /* USER_WRITABLE >= GROUP_WRITABLE */                                  \
 728         BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) +       \
 729         /* OTHER_WRITABLE?  Generally considered a bad idea. */                \
 730         BUILD_BUG_ON_ZERO((perms) & 2) +                                       \
 731         (perms))
 732#endif
 733