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/align.h>
   7#include <linux/limits.h>
   8#include <linux/linkage.h>
   9#include <linux/stddef.h>
  10#include <linux/types.h>
  11#include <linux/compiler.h>
  12#include <linux/bitops.h>
  13#include <linux/log2.h>
  14#include <linux/math.h>
  15#include <linux/minmax.h>
  16#include <linux/typecheck.h>
  17#include <linux/printk.h>
  18#include <linux/build_bug.h>
  19#include <linux/static_call_types.h>
  20#include <asm/byteorder.h>
  21
  22#include <uapi/linux/kernel.h>
  23
  24#define STACK_MAGIC     0xdeadbeef
  25
  26/**
  27 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
  28 * @x: value to repeat
  29 *
  30 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
  31 */
  32#define REPEAT_BYTE(x)  ((~0ul / 0xff) * (x))
  33
  34/* generic data direction definitions */
  35#define READ                    0
  36#define WRITE                   1
  37
  38/**
  39 * ARRAY_SIZE - get the number of elements in array @arr
  40 * @arr: array to be sized
  41 */
  42#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
  43
  44#define PTR_IF(cond, ptr)       ((cond) ? (ptr) : NULL)
  45
  46#define u64_to_user_ptr(x) (            \
  47{                                       \
  48        typecheck(u64, (x));            \
  49        (void __user *)(uintptr_t)(x);  \
  50}                                       \
  51)
  52
  53#define typeof_member(T, m)     typeof(((T*)0)->m)
  54
  55#define _RET_IP_                (unsigned long)__builtin_return_address(0)
  56#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })
  57
  58/**
  59 * upper_32_bits - return bits 32-63 of a number
  60 * @n: the number we're accessing
  61 *
  62 * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
  63 * the "right shift count >= width of type" warning when that quantity is
  64 * 32-bits.
  65 */
  66#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
  67
  68/**
  69 * lower_32_bits - return bits 0-31 of a number
  70 * @n: the number we're accessing
  71 */
  72#define lower_32_bits(n) ((u32)((n) & 0xffffffff))
  73
  74struct completion;
  75struct pt_regs;
  76struct user;
  77
  78#ifdef CONFIG_PREEMPT_VOLUNTARY
  79
  80extern int __cond_resched(void);
  81# define might_resched() __cond_resched()
  82
  83#elif defined(CONFIG_PREEMPT_DYNAMIC)
  84
  85extern int __cond_resched(void);
  86
  87DECLARE_STATIC_CALL(might_resched, __cond_resched);
  88
  89static __always_inline void might_resched(void)
  90{
  91        static_call_mod(might_resched)();
  92}
  93
  94#else
  95
  96# define might_resched() do { } while (0)
  97
  98#endif /* CONFIG_PREEMPT_* */
  99
 100#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 101extern void ___might_sleep(const char *file, int line, int preempt_offset);
 102extern void __might_sleep(const char *file, int line, int preempt_offset);
 103extern void __cant_sleep(const char *file, int line, int preempt_offset);
 104extern void __cant_migrate(const char *file, int line);
 105
 106/**
 107 * might_sleep - annotation for functions that can sleep
 108 *
 109 * this macro will print a stack trace if it is executed in an atomic
 110 * context (spinlock, irq-handler, ...). Additional sections where blocking is
 111 * not allowed can be annotated with non_block_start() and non_block_end()
 112 * pairs.
 113 *
 114 * This is a useful debugging help to be able to catch problems early and not
 115 * be bitten later when the calling function happens to sleep when it is not
 116 * supposed to.
 117 */
 118# define might_sleep() \
 119        do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
 120/**
 121 * cant_sleep - annotation for functions that cannot sleep
 122 *
 123 * this macro will print a stack trace if it is executed with preemption enabled
 124 */
 125# define cant_sleep() \
 126        do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
 127# define sched_annotate_sleep() (current->task_state_change = 0)
 128
 129/**
 130 * cant_migrate - annotation for functions that cannot migrate
 131 *
 132 * Will print a stack trace if executed in code which is migratable
 133 */
 134# define cant_migrate()                                                 \
 135        do {                                                            \
 136                if (IS_ENABLED(CONFIG_SMP))                             \
 137                        __cant_migrate(__FILE__, __LINE__);             \
 138        } while (0)
 139
 140/**
 141 * non_block_start - annotate the start of section where sleeping is prohibited
 142 *
 143 * This is on behalf of the oom reaper, specifically when it is calling the mmu
 144 * notifiers. The problem is that if the notifier were to block on, for example,
 145 * mutex_lock() and if the process which holds that mutex were to perform a
 146 * sleeping memory allocation, the oom reaper is now blocked on completion of
 147 * that memory allocation. Other blocking calls like wait_event() pose similar
 148 * issues.
 149 */
 150# define non_block_start() (current->non_block_count++)
 151/**
 152 * non_block_end - annotate the end of section where sleeping is prohibited
 153 *
 154 * Closes a section opened by non_block_start().
 155 */
 156# define non_block_end() WARN_ON(current->non_block_count-- == 0)
 157#else
 158  static inline void ___might_sleep(const char *file, int line,
 159                                   int preempt_offset) { }
 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# define cant_sleep() do { } while (0)
 164# define cant_migrate()         do { } while (0)
 165# define sched_annotate_sleep() do { } while (0)
 166# define non_block_start() do { } while (0)
 167# define non_block_end() do { } while (0)
 168#endif
 169
 170#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
 171
 172#if defined(CONFIG_MMU) && \
 173        (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
 174#define might_fault() __might_fault(__FILE__, __LINE__)
 175void __might_fault(const char *file, int line);
 176#else
 177static inline void might_fault(void) { }
 178#endif
 179
 180extern struct atomic_notifier_head panic_notifier_list;
 181extern long (*panic_blink)(int state);
 182__printf(1, 2)
 183void panic(const char *fmt, ...) __noreturn __cold;
 184void nmi_panic(struct pt_regs *regs, const char *msg);
 185extern void oops_enter(void);
 186extern void oops_exit(void);
 187extern bool oops_may_print(void);
 188void do_exit(long error_code) __noreturn;
 189void complete_and_exit(struct completion *, long) __noreturn;
 190
 191/* Internal, do not use. */
 192int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
 193int __must_check _kstrtol(const char *s, unsigned int base, long *res);
 194
 195int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
 196int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
 197
 198/**
 199 * kstrtoul - convert a string to an unsigned long
 200 * @s: The start of the string. The string must be null-terminated, and may also
 201 *  include a single newline before its terminating null. The first character
 202 *  may also be a plus sign, but not a minus sign.
 203 * @base: The number base to use. The maximum supported base is 16. If base is
 204 *  given as 0, then the base of the string is automatically detected with the
 205 *  conventional semantics - If it begins with 0x the number will be parsed as a
 206 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 207 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 208 * @res: Where to write the result of the conversion on success.
 209 *
 210 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 211 * Preferred over simple_strtoul(). Return code must be checked.
 212*/
 213static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
 214{
 215        /*
 216         * We want to shortcut function call, but
 217         * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
 218         */
 219        if (sizeof(unsigned long) == sizeof(unsigned long long) &&
 220            __alignof__(unsigned long) == __alignof__(unsigned long long))
 221                return kstrtoull(s, base, (unsigned long long *)res);
 222        else
 223                return _kstrtoul(s, base, res);
 224}
 225
 226/**
 227 * kstrtol - convert a string to a long
 228 * @s: The start of the string. The string must be null-terminated, and may also
 229 *  include a single newline before its terminating null. The first character
 230 *  may also be a plus sign or a minus sign.
 231 * @base: The number base to use. The maximum supported base is 16. If base is
 232 *  given as 0, then the base of the string is automatically detected with the
 233 *  conventional semantics - If it begins with 0x the number will be parsed as a
 234 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 235 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 236 * @res: Where to write the result of the conversion on success.
 237 *
 238 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 239 * Preferred over simple_strtol(). Return code must be checked.
 240 */
 241static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
 242{
 243        /*
 244         * We want to shortcut function call, but
 245         * __builtin_types_compatible_p(long, long long) = 0.
 246         */
 247        if (sizeof(long) == sizeof(long long) &&
 248            __alignof__(long) == __alignof__(long long))
 249                return kstrtoll(s, base, (long long *)res);
 250        else
 251                return _kstrtol(s, base, res);
 252}
 253
 254int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
 255int __must_check kstrtoint(const char *s, unsigned int base, int *res);
 256
 257static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
 258{
 259        return kstrtoull(s, base, res);
 260}
 261
 262static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
 263{
 264        return kstrtoll(s, base, res);
 265}
 266
 267static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
 268{
 269        return kstrtouint(s, base, res);
 270}
 271
 272static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
 273{
 274        return kstrtoint(s, base, res);
 275}
 276
 277int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
 278int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 279int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 280int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 281int __must_check kstrtobool(const char *s, bool *res);
 282
 283int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 284int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
 285int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
 286int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
 287int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
 288int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
 289int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
 290int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
 291int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
 292int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
 293int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
 294
 295static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
 296{
 297        return kstrtoull_from_user(s, count, base, res);
 298}
 299
 300static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
 301{
 302        return kstrtoll_from_user(s, count, base, res);
 303}
 304
 305static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
 306{
 307        return kstrtouint_from_user(s, count, base, res);
 308}
 309
 310static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
 311{
 312        return kstrtoint_from_user(s, count, base, res);
 313}
 314
 315/*
 316 * Use kstrto<foo> instead.
 317 *
 318 * NOTE: simple_strto<foo> does not check for the range overflow and,
 319 *       depending on the input, may give interesting results.
 320 *
 321 * Use these functions if and only if you cannot use kstrto<foo>, because
 322 * the conversion ends on the first non-digit character, which may be far
 323 * beyond the supported range. It might be useful to parse the strings like
 324 * 10x50 or 12:21 without altering original string or temporary buffer in use.
 325 * Keep in mind above caveat.
 326 */
 327
 328extern unsigned long simple_strtoul(const char *,char **,unsigned int);
 329extern long simple_strtol(const char *,char **,unsigned int);
 330extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
 331extern long long simple_strtoll(const char *,char **,unsigned int);
 332
 333extern int num_to_str(char *buf, int size,
 334                      unsigned long long num, unsigned int width);
 335
 336/* lib/printf utilities */
 337
 338extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
 339extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
 340extern __printf(3, 4)
 341int snprintf(char *buf, size_t size, const char *fmt, ...);
 342extern __printf(3, 0)
 343int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
 344extern __printf(3, 4)
 345int scnprintf(char *buf, size_t size, const char *fmt, ...);
 346extern __printf(3, 0)
 347int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 348extern __printf(2, 3) __malloc
 349char *kasprintf(gfp_t gfp, const char *fmt, ...);
 350extern __printf(2, 0) __malloc
 351char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
 352extern __printf(2, 0)
 353const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
 354
 355extern __scanf(2, 3)
 356int sscanf(const char *, const char *, ...);
 357extern __scanf(2, 0)
 358int vsscanf(const char *, const char *, va_list);
 359
 360extern int get_option(char **str, int *pint);
 361extern char *get_options(const char *str, int nints, int *ints);
 362extern unsigned long long memparse(const char *ptr, char **retptr);
 363extern bool parse_option_str(const char *str, const char *option);
 364extern char *next_arg(char *args, char **param, char **val);
 365
 366extern int core_kernel_text(unsigned long addr);
 367extern int init_kernel_text(unsigned long addr);
 368extern int core_kernel_data(unsigned long addr);
 369extern int __kernel_text_address(unsigned long addr);
 370extern int kernel_text_address(unsigned long addr);
 371extern int func_ptr_is_kernel_text(void *ptr);
 372
 373#ifdef CONFIG_SMP
 374extern unsigned int sysctl_oops_all_cpu_backtrace;
 375#else
 376#define sysctl_oops_all_cpu_backtrace 0
 377#endif /* CONFIG_SMP */
 378
 379extern void bust_spinlocks(int yes);
 380extern int panic_timeout;
 381extern unsigned long panic_print;
 382extern int panic_on_oops;
 383extern int panic_on_unrecovered_nmi;
 384extern int panic_on_io_nmi;
 385extern int panic_on_warn;
 386extern unsigned long panic_on_taint;
 387extern bool panic_on_taint_nousertaint;
 388extern int sysctl_panic_on_rcu_stall;
 389extern int sysctl_max_rcu_stall_to_panic;
 390extern int sysctl_panic_on_stackoverflow;
 391
 392extern bool crash_kexec_post_notifiers;
 393
 394/*
 395 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
 396 * holds a CPU number which is executing panic() currently. A value of
 397 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
 398 */
 399extern atomic_t panic_cpu;
 400#define PANIC_CPU_INVALID       -1
 401
 402/*
 403 * Only to be used by arch init code. If the user over-wrote the default
 404 * CONFIG_PANIC_TIMEOUT, honor it.
 405 */
 406static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
 407{
 408        if (panic_timeout == arch_default_timeout)
 409                panic_timeout = timeout;
 410}
 411extern const char *print_tainted(void);
 412enum lockdep_ok {
 413        LOCKDEP_STILL_OK,
 414        LOCKDEP_NOW_UNRELIABLE
 415};
 416extern void add_taint(unsigned flag, enum lockdep_ok);
 417extern int test_taint(unsigned flag);
 418extern unsigned long get_taint(void);
 419extern int root_mountflags;
 420
 421extern bool early_boot_irqs_disabled;
 422
 423/*
 424 * Values used for system_state. Ordering of the states must not be changed
 425 * as code checks for <, <=, >, >= STATE.
 426 */
 427extern enum system_states {
 428        SYSTEM_BOOTING,
 429        SYSTEM_SCHEDULING,
 430        SYSTEM_RUNNING,
 431        SYSTEM_HALT,
 432        SYSTEM_POWER_OFF,
 433        SYSTEM_RESTART,
 434        SYSTEM_SUSPEND,
 435} system_state;
 436
 437/* This cannot be an enum because some may be used in assembly source. */
 438#define TAINT_PROPRIETARY_MODULE        0
 439#define TAINT_FORCED_MODULE             1
 440#define TAINT_CPU_OUT_OF_SPEC           2
 441#define TAINT_FORCED_RMMOD              3
 442#define TAINT_MACHINE_CHECK             4
 443#define TAINT_BAD_PAGE                  5
 444#define TAINT_USER                      6
 445#define TAINT_DIE                       7
 446#define TAINT_OVERRIDDEN_ACPI_TABLE     8
 447#define TAINT_WARN                      9
 448#define TAINT_CRAP                      10
 449#define TAINT_FIRMWARE_WORKAROUND       11
 450#define TAINT_OOT_MODULE                12
 451#define TAINT_UNSIGNED_MODULE           13
 452#define TAINT_SOFTLOCKUP                14
 453#define TAINT_LIVEPATCH                 15
 454#define TAINT_AUX                       16
 455#define TAINT_RANDSTRUCT                17
 456#define TAINT_FLAGS_COUNT               18
 457#define TAINT_FLAGS_MAX                 ((1UL << TAINT_FLAGS_COUNT) - 1)
 458
 459struct taint_flag {
 460        char c_true;    /* character printed when tainted */
 461        char c_false;   /* character printed when not tainted */
 462        bool module;    /* also show as a per-module taint flag */
 463};
 464
 465extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
 466
 467extern const char hex_asc[];
 468#define hex_asc_lo(x)   hex_asc[((x) & 0x0f)]
 469#define hex_asc_hi(x)   hex_asc[((x) & 0xf0) >> 4]
 470
 471static inline char *hex_byte_pack(char *buf, u8 byte)
 472{
 473        *buf++ = hex_asc_hi(byte);
 474        *buf++ = hex_asc_lo(byte);
 475        return buf;
 476}
 477
 478extern const char hex_asc_upper[];
 479#define hex_asc_upper_lo(x)     hex_asc_upper[((x) & 0x0f)]
 480#define hex_asc_upper_hi(x)     hex_asc_upper[((x) & 0xf0) >> 4]
 481
 482static inline char *hex_byte_pack_upper(char *buf, u8 byte)
 483{
 484        *buf++ = hex_asc_upper_hi(byte);
 485        *buf++ = hex_asc_upper_lo(byte);
 486        return buf;
 487}
 488
 489extern int hex_to_bin(char ch);
 490extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 491extern char *bin2hex(char *dst, const void *src, size_t count);
 492
 493bool mac_pton(const char *s, u8 *mac);
 494
 495/*
 496 * General tracing related utility functions - trace_printk(),
 497 * tracing_on/tracing_off and tracing_start()/tracing_stop
 498 *
 499 * Use tracing_on/tracing_off when you want to quickly turn on or off
 500 * tracing. It simply enables or disables the recording of the trace events.
 501 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
 502 * file, which gives a means for the kernel and userspace to interact.
 503 * Place a tracing_off() in the kernel where you want tracing to end.
 504 * From user space, examine the trace, and then echo 1 > tracing_on
 505 * to continue tracing.
 506 *
 507 * tracing_stop/tracing_start has slightly more overhead. It is used
 508 * by things like suspend to ram where disabling the recording of the
 509 * trace is not enough, but tracing must actually stop because things
 510 * like calling smp_processor_id() may crash the system.
 511 *
 512 * Most likely, you want to use tracing_on/tracing_off.
 513 */
 514
 515enum ftrace_dump_mode {
 516        DUMP_NONE,
 517        DUMP_ALL,
 518        DUMP_ORIG,
 519};
 520
 521#ifdef CONFIG_TRACING
 522void tracing_on(void);
 523void tracing_off(void);
 524int tracing_is_on(void);
 525void tracing_snapshot(void);
 526void tracing_snapshot_alloc(void);
 527
 528extern void tracing_start(void);
 529extern void tracing_stop(void);
 530
 531static inline __printf(1, 2)
 532void ____trace_printk_check_format(const char *fmt, ...)
 533{
 534}
 535#define __trace_printk_check_format(fmt, args...)                       \
 536do {                                                                    \
 537        if (0)                                                          \
 538                ____trace_printk_check_format(fmt, ##args);             \
 539} while (0)
 540
 541/**
 542 * trace_printk - printf formatting in the ftrace buffer
 543 * @fmt: the printf format for printing
 544 *
 545 * Note: __trace_printk is an internal function for trace_printk() and
 546 *       the @ip is passed in via the trace_printk() macro.
 547 *
 548 * This function allows a kernel developer to debug fast path sections
 549 * that printk is not appropriate for. By scattering in various
 550 * printk like tracing in the code, a developer can quickly see
 551 * where problems are occurring.
 552 *
 553 * This is intended as a debugging tool for the developer only.
 554 * Please refrain from leaving trace_printks scattered around in
 555 * your code. (Extra memory is used for special buffers that are
 556 * allocated when trace_printk() is used.)
 557 *
 558 * A little optimization trick is done here. If there's only one
 559 * argument, there's no need to scan the string for printf formats.
 560 * The trace_puts() will suffice. But how can we take advantage of
 561 * using trace_puts() when trace_printk() has only one argument?
 562 * By stringifying the args and checking the size we can tell
 563 * whether or not there are args. __stringify((__VA_ARGS__)) will
 564 * turn into "()\0" with a size of 3 when there are no args, anything
 565 * else will be bigger. All we need to do is define a string to this,
 566 * and then take its size and compare to 3. If it's bigger, use
 567 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
 568 * let gcc optimize the rest.
 569 */
 570
 571#define trace_printk(fmt, ...)                          \
 572do {                                                    \
 573        char _______STR[] = __stringify((__VA_ARGS__)); \
 574        if (sizeof(_______STR) > 3)                     \
 575                do_trace_printk(fmt, ##__VA_ARGS__);    \
 576        else                                            \
 577                trace_puts(fmt);                        \
 578} while (0)
 579
 580#define do_trace_printk(fmt, args...)                                   \
 581do {                                                                    \
 582        static const char *trace_printk_fmt __used                      \
 583                __section("__trace_printk_fmt") =                       \
 584                __builtin_constant_p(fmt) ? fmt : NULL;                 \
 585                                                                        \
 586        __trace_printk_check_format(fmt, ##args);                       \
 587                                                                        \
 588        if (__builtin_constant_p(fmt))                                  \
 589                __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args);   \
 590        else                                                            \
 591                __trace_printk(_THIS_IP_, fmt, ##args);                 \
 592} while (0)
 593
 594extern __printf(2, 3)
 595int __trace_bprintk(unsigned long ip, const char *fmt, ...);
 596
 597extern __printf(2, 3)
 598int __trace_printk(unsigned long ip, const char *fmt, ...);
 599
 600/**
 601 * trace_puts - write a string into the ftrace buffer
 602 * @str: the string to record
 603 *
 604 * Note: __trace_bputs is an internal function for trace_puts and
 605 *       the @ip is passed in via the trace_puts macro.
 606 *
 607 * This is similar to trace_printk() but is made for those really fast
 608 * paths that a developer wants the least amount of "Heisenbug" effects,
 609 * where the processing of the print format is still too much.
 610 *
 611 * This function allows a kernel developer to debug fast path sections
 612 * that printk is not appropriate for. By scattering in various
 613 * printk like tracing in the code, a developer can quickly see
 614 * where problems are occurring.
 615 *
 616 * This is intended as a debugging tool for the developer only.
 617 * Please refrain from leaving trace_puts scattered around in
 618 * your code. (Extra memory is used for special buffers that are
 619 * allocated when trace_puts() is used.)
 620 *
 621 * Returns: 0 if nothing was written, positive # if string was.
 622 *  (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
 623 */
 624
 625#define trace_puts(str) ({                                              \
 626        static const char *trace_printk_fmt __used                      \
 627                __section("__trace_printk_fmt") =                       \
 628                __builtin_constant_p(str) ? str : NULL;                 \
 629                                                                        \
 630        if (__builtin_constant_p(str))                                  \
 631                __trace_bputs(_THIS_IP_, trace_printk_fmt);             \
 632        else                                                            \
 633                __trace_puts(_THIS_IP_, str, strlen(str));              \
 634})
 635extern int __trace_bputs(unsigned long ip, const char *str);
 636extern int __trace_puts(unsigned long ip, const char *str, int size);
 637
 638extern void trace_dump_stack(int skip);
 639
 640/*
 641 * The double __builtin_constant_p is because gcc will give us an error
 642 * if we try to allocate the static variable to fmt if it is not a
 643 * constant. Even with the outer if statement.
 644 */
 645#define ftrace_vprintk(fmt, vargs)                                      \
 646do {                                                                    \
 647        if (__builtin_constant_p(fmt)) {                                \
 648                static const char *trace_printk_fmt __used              \
 649                  __section("__trace_printk_fmt") =                     \
 650                        __builtin_constant_p(fmt) ? fmt : NULL;         \
 651                                                                        \
 652                __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs);  \
 653        } else                                                          \
 654                __ftrace_vprintk(_THIS_IP_, fmt, vargs);                \
 655} while (0)
 656
 657extern __printf(2, 0) int
 658__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
 659
 660extern __printf(2, 0) int
 661__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
 662
 663extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
 664#else
 665static inline void tracing_start(void) { }
 666static inline void tracing_stop(void) { }
 667static inline void trace_dump_stack(int skip) { }
 668
 669static inline void tracing_on(void) { }
 670static inline void tracing_off(void) { }
 671static inline int tracing_is_on(void) { return 0; }
 672static inline void tracing_snapshot(void) { }
 673static inline void tracing_snapshot_alloc(void) { }
 674
 675static inline __printf(1, 2)
 676int trace_printk(const char *fmt, ...)
 677{
 678        return 0;
 679}
 680static __printf(1, 0) inline int
 681ftrace_vprintk(const char *fmt, va_list ap)
 682{
 683        return 0;
 684}
 685static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
 686#endif /* CONFIG_TRACING */
 687
 688/* This counts to 12. Any more, it will return 13th argument. */
 689#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
 690#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
 691
 692#define __CONCAT(a, b) a ## b
 693#define CONCATENATE(a, b) __CONCAT(a, b)
 694
 695/**
 696 * container_of - cast a member of a structure out to the containing structure
 697 * @ptr:        the pointer to the member.
 698 * @type:       the type of the container struct this is embedded in.
 699 * @member:     the name of the member within the struct.
 700 *
 701 */
 702#define container_of(ptr, type, member) ({                              \
 703        void *__mptr = (void *)(ptr);                                   \
 704        BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&   \
 705                         !__same_type(*(ptr), void),                    \
 706                         "pointer type mismatch in container_of()");    \
 707        ((type *)(__mptr - offsetof(type, member))); })
 708
 709/**
 710 * container_of_safe - cast a member of a structure out to the containing structure
 711 * @ptr:        the pointer to the member.
 712 * @type:       the type of the container struct this is embedded in.
 713 * @member:     the name of the member within the struct.
 714 *
 715 * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged.
 716 */
 717#define container_of_safe(ptr, type, member) ({                         \
 718        void *__mptr = (void *)(ptr);                                   \
 719        BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&   \
 720                         !__same_type(*(ptr), void),                    \
 721                         "pointer type mismatch in container_of()");    \
 722        IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) :                     \
 723                ((type *)(__mptr - offsetof(type, member))); })
 724
 725/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
 726#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 727# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
 728#endif
 729
 730/* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
 731#define VERIFY_OCTAL_PERMISSIONS(perms)                                         \
 732        (BUILD_BUG_ON_ZERO((perms) < 0) +                                       \
 733         BUILD_BUG_ON_ZERO((perms) > 0777) +                                    \
 734         /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */                \
 735         BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) +       \
 736         BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) +              \
 737         /* USER_WRITABLE >= GROUP_WRITABLE */                                  \
 738         BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) +       \
 739         /* OTHER_WRITABLE?  Generally considered a bad idea. */                \
 740         BUILD_BUG_ON_ZERO((perms) & 2) +                                       \
 741         (perms))
 742#endif
 743