1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_KERNEL_H
3 #define _LINUX_KERNEL_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/typecheck.h>
14 #include <linux/printk.h>
15 #include <linux/build_bug.h>
16 #include <asm/byteorder.h>
17 #include <uapi/linux/kernel.h>
19 #define USHRT_MAX ((u16)(~0U))
20 #define SHRT_MAX ((s16)(USHRT_MAX>>1))
21 #define SHRT_MIN ((s16)(-SHRT_MAX - 1))
22 #define INT_MAX ((int)(~0U>>1))
23 #define INT_MIN (-INT_MAX - 1)
24 #define UINT_MAX (~0U)
25 #define LONG_MAX ((long)(~0UL>>1))
26 #define LONG_MIN (-LONG_MAX - 1)
27 #define ULONG_MAX (~0UL)
28 #define LLONG_MAX ((long long)(~0ULL>>1))
29 #define LLONG_MIN (-LLONG_MAX - 1)
30 #define ULLONG_MAX (~0ULL)
31 #define SIZE_MAX (~(size_t)0)
33 #define U8_MAX ((u8)~0U)
34 #define S8_MAX ((s8)(U8_MAX>>1))
35 #define S8_MIN ((s8)(-S8_MAX - 1))
36 #define U16_MAX ((u16)~0U)
37 #define S16_MAX ((s16)(U16_MAX>>1))
38 #define S16_MIN ((s16)(-S16_MAX - 1))
39 #define U32_MAX ((u32)~0U)
40 #define S32_MAX ((s32)(U32_MAX>>1))
41 #define S32_MIN ((s32)(-S32_MAX - 1))
42 #define U64_MAX ((u64)~0ULL)
43 #define S64_MAX ((s64)(U64_MAX>>1))
44 #define S64_MIN ((s64)(-S64_MAX - 1))
46 #define STACK_MAGIC 0xdeadbeef
49 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
52 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
54 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
56 /* @a is a power of 2 value */
57 #define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
58 #define ALIGN_DOWN(x, a) __ALIGN_KERNEL((x) - ((a) - 1), (a))
59 #define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
60 #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
61 #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
63 /* generic data direction definitions */
68 * ARRAY_SIZE - get the number of elements in array @arr
69 * @arr: array to be sized
71 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
73 #define u64_to_user_ptr(x) ( \
76 (void __user *)(uintptr_t)x; \
81 * This looks more complex than it should be. But we need to
82 * get the type for the ~ right in round_down (it needs to be
83 * as wide as the result!), and we want to evaluate the macro
84 * arguments just once each.
86 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
87 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
88 #define round_down(x, y) ((x) & ~__round_mask(x, y))
91 * FIELD_SIZEOF - get the size of a struct's field
92 * @t: the target struct
93 * @f: the target struct's field
94 * Return: the size of @f in the struct definition without having a
95 * declared instance of @t.
97 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
99 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
101 #define DIV_ROUND_DOWN_ULL(ll, d) \
102 ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; })
104 #define DIV_ROUND_UP_ULL(ll, d) DIV_ROUND_DOWN_ULL((ll) + (d) - 1, (d))
106 #if BITS_PER_LONG == 32
107 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
109 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
112 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
113 #define roundup(x, y) ( \
115 const typeof(y) __y = y; \
116 (((x) + (__y - 1)) / __y) * __y; \
119 #define rounddown(x, y) ( \
121 typeof(x) __x = (x); \
127 * Divide positive or negative dividend by positive or negative divisor
128 * and round to closest integer. Result is undefined for negative
129 * divisors if the dividend variable type is unsigned and for negative
130 * dividends if the divisor variable type is unsigned.
132 #define DIV_ROUND_CLOSEST(x, divisor)( \
135 typeof(divisor) __d = divisor; \
136 (((typeof(x))-1) > 0 || \
137 ((typeof(divisor))-1) > 0 || \
138 (((__x) > 0) == ((__d) > 0))) ? \
139 (((__x) + ((__d) / 2)) / (__d)) : \
140 (((__x) - ((__d) / 2)) / (__d)); \
144 * Same as above but for u64 dividends. divisor must be a 32-bit
147 #define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
149 typeof(divisor) __d = divisor; \
150 unsigned long long _tmp = (x) + (__d) / 2; \
157 * Multiplies an integer by a fraction, while avoiding unnecessary
158 * overflow or loss of precision.
160 #define mult_frac(x, numer, denom)( \
162 typeof(x) quot = (x) / (denom); \
163 typeof(x) rem = (x) % (denom); \
164 (quot * (numer)) + ((rem * (numer)) / (denom)); \
169 #define _RET_IP_ (unsigned long)__builtin_return_address(0)
170 #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
173 # include <asm/div64.h>
174 # define sector_div(a, b) do_div(a, b)
176 # define sector_div(n, b)( \
187 * upper_32_bits - return bits 32-63 of a number
188 * @n: the number we're accessing
190 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
191 * the "right shift count >= width of type" warning when that quantity is
194 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
197 * lower_32_bits - return bits 0-31 of a number
198 * @n: the number we're accessing
200 #define lower_32_bits(n) ((u32)(n))
206 #ifdef CONFIG_PREEMPT_VOLUNTARY
207 extern int _cond_resched(void);
208 # define might_resched() _cond_resched()
210 # define might_resched() do { } while (0)
213 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
214 void ___might_sleep(const char *file
, int line
, int preempt_offset
);
215 void __might_sleep(const char *file
, int line
, int preempt_offset
);
217 * might_sleep - annotation for functions that can sleep
219 * this macro will print a stack trace if it is executed in an atomic
220 * context (spinlock, irq-handler, ...).
222 * This is a useful debugging help to be able to catch problems early and not
223 * be bitten later when the calling function happens to sleep when it is not
226 # define might_sleep() \
227 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
228 # define sched_annotate_sleep() (current->task_state_change = 0)
230 static inline void ___might_sleep(const char *file
, int line
,
231 int preempt_offset
) { }
232 static inline void __might_sleep(const char *file
, int line
,
233 int preempt_offset
) { }
234 # define might_sleep() do { might_resched(); } while (0)
235 # define sched_annotate_sleep() do { } while (0)
238 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
241 * abs - return absolute value of an argument
242 * @x: the value. If it is unsigned type, it is converted to signed type first.
243 * char is treated as if it was signed (regardless of whether it really is)
244 * but the macro's return type is preserved as char.
246 * Return: an absolute value of x.
248 #define abs(x) __abs_choose_expr(x, long long, \
249 __abs_choose_expr(x, long, \
250 __abs_choose_expr(x, int, \
251 __abs_choose_expr(x, short, \
252 __abs_choose_expr(x, char, \
253 __builtin_choose_expr( \
254 __builtin_types_compatible_p(typeof(x), char), \
255 (char)({ signed char __x = (x); __x<0?-__x:__x; }), \
258 #define __abs_choose_expr(x, type, other) __builtin_choose_expr( \
259 __builtin_types_compatible_p(typeof(x), signed type) || \
260 __builtin_types_compatible_p(typeof(x), unsigned type), \
261 ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
264 * reciprocal_scale - "scale" a value into range [0, ep_ro)
266 * @ep_ro: right open interval endpoint
268 * Perform a "reciprocal multiplication" in order to "scale" a value into
269 * range [0, @ep_ro), where the upper interval endpoint is right-open.
270 * This is useful, e.g. for accessing a index of an array containing
271 * @ep_ro elements, for example. Think of it as sort of modulus, only that
272 * the result isn't that of modulo. ;) Note that if initial input is a
273 * small value, then result will return 0.
275 * Return: a result based on @val in interval [0, @ep_ro).
277 static inline u32
reciprocal_scale(u32 val
, u32 ep_ro
)
279 return (u32
)(((u64
) val
* ep_ro
) >> 32);
282 #if defined(CONFIG_MMU) && \
283 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
284 #define might_fault() __might_fault(__FILE__, __LINE__)
285 void __might_fault(const char *file
, int line
);
287 static inline void might_fault(void) { }
290 extern struct atomic_notifier_head panic_notifier_list
;
291 extern long (*panic_blink
)(int state
);
293 void panic(const char *fmt
, ...) __noreturn __cold
;
294 void nmi_panic(struct pt_regs
*regs
, const char *msg
);
295 extern void oops_enter(void);
296 extern void oops_exit(void);
297 void print_oops_end_marker(void);
298 extern int oops_may_print(void);
299 void do_exit(long error_code
) __noreturn
;
300 void complete_and_exit(struct completion
*, long) __noreturn
;
302 #ifdef CONFIG_ARCH_HAS_REFCOUNT
303 void refcount_error_report(struct pt_regs
*regs
, const char *err
);
305 static inline void refcount_error_report(struct pt_regs
*regs
, const char *err
)
309 /* Internal, do not use. */
310 int __must_check
_kstrtoul(const char *s
, unsigned int base
, unsigned long *res
);
311 int __must_check
_kstrtol(const char *s
, unsigned int base
, long *res
);
313 int __must_check
kstrtoull(const char *s
, unsigned int base
, unsigned long long *res
);
314 int __must_check
kstrtoll(const char *s
, unsigned int base
, long long *res
);
317 * kstrtoul - convert a string to an unsigned long
318 * @s: The start of the string. The string must be null-terminated, and may also
319 * include a single newline before its terminating null. The first character
320 * may also be a plus sign, but not a minus sign.
321 * @base: The number base to use. The maximum supported base is 16. If base is
322 * given as 0, then the base of the string is automatically detected with the
323 * conventional semantics - If it begins with 0x the number will be parsed as a
324 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
325 * parsed as an octal number. Otherwise it will be parsed as a decimal.
326 * @res: Where to write the result of the conversion on success.
328 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
329 * Used as a replacement for the obsolete simple_strtoull. Return code must
332 static inline int __must_check
kstrtoul(const char *s
, unsigned int base
, unsigned long *res
)
335 * We want to shortcut function call, but
336 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
338 if (sizeof(unsigned long) == sizeof(unsigned long long) &&
339 __alignof__(unsigned long) == __alignof__(unsigned long long))
340 return kstrtoull(s
, base
, (unsigned long long *)res
);
342 return _kstrtoul(s
, base
, res
);
346 * kstrtol - convert a string to a long
347 * @s: The start of the string. The string must be null-terminated, and may also
348 * include a single newline before its terminating null. The first character
349 * may also be a plus sign or a minus sign.
350 * @base: The number base to use. The maximum supported base is 16. If base is
351 * given as 0, then the base of the string is automatically detected with the
352 * conventional semantics - If it begins with 0x the number will be parsed as a
353 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
354 * parsed as an octal number. Otherwise it will be parsed as a decimal.
355 * @res: Where to write the result of the conversion on success.
357 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
358 * Used as a replacement for the obsolete simple_strtoull. Return code must
361 static inline int __must_check
kstrtol(const char *s
, unsigned int base
, long *res
)
364 * We want to shortcut function call, but
365 * __builtin_types_compatible_p(long, long long) = 0.
367 if (sizeof(long) == sizeof(long long) &&
368 __alignof__(long) == __alignof__(long long))
369 return kstrtoll(s
, base
, (long long *)res
);
371 return _kstrtol(s
, base
, res
);
374 int __must_check
kstrtouint(const char *s
, unsigned int base
, unsigned int *res
);
375 int __must_check
kstrtoint(const char *s
, unsigned int base
, int *res
);
377 static inline int __must_check
kstrtou64(const char *s
, unsigned int base
, u64
*res
)
379 return kstrtoull(s
, base
, res
);
382 static inline int __must_check
kstrtos64(const char *s
, unsigned int base
, s64
*res
)
384 return kstrtoll(s
, base
, res
);
387 static inline int __must_check
kstrtou32(const char *s
, unsigned int base
, u32
*res
)
389 return kstrtouint(s
, base
, res
);
392 static inline int __must_check
kstrtos32(const char *s
, unsigned int base
, s32
*res
)
394 return kstrtoint(s
, base
, res
);
397 int __must_check
kstrtou16(const char *s
, unsigned int base
, u16
*res
);
398 int __must_check
kstrtos16(const char *s
, unsigned int base
, s16
*res
);
399 int __must_check
kstrtou8(const char *s
, unsigned int base
, u8
*res
);
400 int __must_check
kstrtos8(const char *s
, unsigned int base
, s8
*res
);
401 int __must_check
kstrtobool(const char *s
, bool *res
);
403 int __must_check
kstrtoull_from_user(const char __user
*s
, size_t count
, unsigned int base
, unsigned long long *res
);
404 int __must_check
kstrtoll_from_user(const char __user
*s
, size_t count
, unsigned int base
, long long *res
);
405 int __must_check
kstrtoul_from_user(const char __user
*s
, size_t count
, unsigned int base
, unsigned long *res
);
406 int __must_check
kstrtol_from_user(const char __user
*s
, size_t count
, unsigned int base
, long *res
);
407 int __must_check
kstrtouint_from_user(const char __user
*s
, size_t count
, unsigned int base
, unsigned int *res
);
408 int __must_check
kstrtoint_from_user(const char __user
*s
, size_t count
, unsigned int base
, int *res
);
409 int __must_check
kstrtou16_from_user(const char __user
*s
, size_t count
, unsigned int base
, u16
*res
);
410 int __must_check
kstrtos16_from_user(const char __user
*s
, size_t count
, unsigned int base
, s16
*res
);
411 int __must_check
kstrtou8_from_user(const char __user
*s
, size_t count
, unsigned int base
, u8
*res
);
412 int __must_check
kstrtos8_from_user(const char __user
*s
, size_t count
, unsigned int base
, s8
*res
);
413 int __must_check
kstrtobool_from_user(const char __user
*s
, size_t count
, bool *res
);
415 static inline int __must_check
kstrtou64_from_user(const char __user
*s
, size_t count
, unsigned int base
, u64
*res
)
417 return kstrtoull_from_user(s
, count
, base
, res
);
420 static inline int __must_check
kstrtos64_from_user(const char __user
*s
, size_t count
, unsigned int base
, s64
*res
)
422 return kstrtoll_from_user(s
, count
, base
, res
);
425 static inline int __must_check
kstrtou32_from_user(const char __user
*s
, size_t count
, unsigned int base
, u32
*res
)
427 return kstrtouint_from_user(s
, count
, base
, res
);
430 static inline int __must_check
kstrtos32_from_user(const char __user
*s
, size_t count
, unsigned int base
, s32
*res
)
432 return kstrtoint_from_user(s
, count
, base
, res
);
435 /* Obsolete, do not use. Use kstrto<foo> instead */
437 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
438 extern long simple_strtol(const char *,char **,unsigned int);
439 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
440 extern long long simple_strtoll(const char *,char **,unsigned int);
442 extern int num_to_str(char *buf
, int size
,
443 unsigned long long num
, unsigned int width
);
445 /* lib/printf utilities */
447 extern __printf(2, 3) int sprintf(char *buf
, const char * fmt
, ...);
448 extern __printf(2, 0) int vsprintf(char *buf
, const char *, va_list);
449 extern __printf(3, 4)
450 int snprintf(char *buf
, size_t size
, const char *fmt
, ...);
451 extern __printf(3, 0)
452 int vsnprintf(char *buf
, size_t size
, const char *fmt
, va_list args
);
453 extern __printf(3, 4)
454 int scnprintf(char *buf
, size_t size
, const char *fmt
, ...);
455 extern __printf(3, 0)
456 int vscnprintf(char *buf
, size_t size
, const char *fmt
, va_list args
);
457 extern __printf(2, 3) __malloc
458 char *kasprintf(gfp_t gfp
, const char *fmt
, ...);
459 extern __printf(2, 0) __malloc
460 char *kvasprintf(gfp_t gfp
, const char *fmt
, va_list args
);
461 extern __printf(2, 0)
462 const char *kvasprintf_const(gfp_t gfp
, const char *fmt
, va_list args
);
465 int sscanf(const char *, const char *, ...);
467 int vsscanf(const char *, const char *, va_list);
469 extern int get_option(char **str
, int *pint
);
470 extern char *get_options(const char *str
, int nints
, int *ints
);
471 extern unsigned long long memparse(const char *ptr
, char **retptr
);
472 extern bool parse_option_str(const char *str
, const char *option
);
473 extern char *next_arg(char *args
, char **param
, char **val
);
475 extern int core_kernel_text(unsigned long addr
);
476 extern int init_kernel_text(unsigned long addr
);
477 extern int core_kernel_data(unsigned long addr
);
478 extern int __kernel_text_address(unsigned long addr
);
479 extern int kernel_text_address(unsigned long addr
);
480 extern int func_ptr_is_kernel_text(void *ptr
);
482 unsigned long int_sqrt(unsigned long);
484 #if BITS_PER_LONG < 64
485 u32
int_sqrt64(u64 x
);
487 static inline u32
int_sqrt64(u64 x
)
489 return (u32
)int_sqrt(x
);
493 extern void bust_spinlocks(int yes
);
494 extern int oops_in_progress
; /* If set, an oops, panic(), BUG() or die() is in progress */
495 extern int panic_timeout
;
496 extern int panic_on_oops
;
497 extern int panic_on_unrecovered_nmi
;
498 extern int panic_on_io_nmi
;
499 extern int panic_on_warn
;
500 extern int sysctl_panic_on_rcu_stall
;
501 extern int sysctl_panic_on_stackoverflow
;
503 extern bool crash_kexec_post_notifiers
;
506 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
507 * holds a CPU number which is executing panic() currently. A value of
508 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
510 extern atomic_t panic_cpu
;
511 #define PANIC_CPU_INVALID -1
514 * Only to be used by arch init code. If the user over-wrote the default
515 * CONFIG_PANIC_TIMEOUT, honor it.
517 static inline void set_arch_panic_timeout(int timeout
, int arch_default_timeout
)
519 if (panic_timeout
== arch_default_timeout
)
520 panic_timeout
= timeout
;
522 extern const char *print_tainted(void);
525 LOCKDEP_NOW_UNRELIABLE
527 extern void add_taint(unsigned flag
, enum lockdep_ok
);
528 extern int test_taint(unsigned flag
);
529 extern unsigned long get_taint(void);
530 extern int root_mountflags
;
532 extern bool early_boot_irqs_disabled
;
535 * Values used for system_state. Ordering of the states must not be changed
536 * as code checks for <, <=, >, >= STATE.
538 extern enum system_states
{
548 /* This cannot be an enum because some may be used in assembly source. */
549 #define TAINT_PROPRIETARY_MODULE 0
550 #define TAINT_FORCED_MODULE 1
551 #define TAINT_CPU_OUT_OF_SPEC 2
552 #define TAINT_FORCED_RMMOD 3
553 #define TAINT_MACHINE_CHECK 4
554 #define TAINT_BAD_PAGE 5
557 #define TAINT_OVERRIDDEN_ACPI_TABLE 8
559 #define TAINT_CRAP 10
560 #define TAINT_FIRMWARE_WORKAROUND 11
561 #define TAINT_OOT_MODULE 12
562 #define TAINT_UNSIGNED_MODULE 13
563 #define TAINT_SOFTLOCKUP 14
564 #define TAINT_LIVEPATCH 15
566 #define TAINT_RANDSTRUCT 17
567 #define TAINT_FLAGS_COUNT 18
570 char c_true
; /* character printed when tainted */
571 char c_false
; /* character printed when not tainted */
572 bool module
; /* also show as a per-module taint flag */
575 extern const struct taint_flag taint_flags
[TAINT_FLAGS_COUNT
];
577 extern const char hex_asc
[];
578 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
579 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
581 static inline char *hex_byte_pack(char *buf
, u8 byte
)
583 *buf
++ = hex_asc_hi(byte
);
584 *buf
++ = hex_asc_lo(byte
);
588 extern const char hex_asc_upper
[];
589 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
590 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
592 static inline char *hex_byte_pack_upper(char *buf
, u8 byte
)
594 *buf
++ = hex_asc_upper_hi(byte
);
595 *buf
++ = hex_asc_upper_lo(byte
);
599 extern int hex_to_bin(char ch
);
600 extern int __must_check
hex2bin(u8
*dst
, const char *src
, size_t count
);
601 extern char *bin2hex(char *dst
, const void *src
, size_t count
);
603 bool mac_pton(const char *s
, u8
*mac
);
606 * General tracing related utility functions - trace_printk(),
607 * tracing_on/tracing_off and tracing_start()/tracing_stop
609 * Use tracing_on/tracing_off when you want to quickly turn on or off
610 * tracing. It simply enables or disables the recording of the trace events.
611 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
612 * file, which gives a means for the kernel and userspace to interact.
613 * Place a tracing_off() in the kernel where you want tracing to end.
614 * From user space, examine the trace, and then echo 1 > tracing_on
615 * to continue tracing.
617 * tracing_stop/tracing_start has slightly more overhead. It is used
618 * by things like suspend to ram where disabling the recording of the
619 * trace is not enough, but tracing must actually stop because things
620 * like calling smp_processor_id() may crash the system.
622 * Most likely, you want to use tracing_on/tracing_off.
625 enum ftrace_dump_mode
{
631 #ifdef CONFIG_TRACING
632 void tracing_on(void);
633 void tracing_off(void);
634 int tracing_is_on(void);
635 void tracing_snapshot(void);
636 void tracing_snapshot_alloc(void);
638 extern void tracing_start(void);
639 extern void tracing_stop(void);
641 static inline __printf(1, 2)
642 void ____trace_printk_check_format(const char *fmt
, ...)
645 #define __trace_printk_check_format(fmt, args...) \
648 ____trace_printk_check_format(fmt, ##args); \
652 * trace_printk - printf formatting in the ftrace buffer
653 * @fmt: the printf format for printing
655 * Note: __trace_printk is an internal function for trace_printk() and
656 * the @ip is passed in via the trace_printk() macro.
658 * This function allows a kernel developer to debug fast path sections
659 * that printk is not appropriate for. By scattering in various
660 * printk like tracing in the code, a developer can quickly see
661 * where problems are occurring.
663 * This is intended as a debugging tool for the developer only.
664 * Please refrain from leaving trace_printks scattered around in
665 * your code. (Extra memory is used for special buffers that are
666 * allocated when trace_printk() is used.)
668 * A little optization trick is done here. If there's only one
669 * argument, there's no need to scan the string for printf formats.
670 * The trace_puts() will suffice. But how can we take advantage of
671 * using trace_puts() when trace_printk() has only one argument?
672 * By stringifying the args and checking the size we can tell
673 * whether or not there are args. __stringify((__VA_ARGS__)) will
674 * turn into "()\0" with a size of 3 when there are no args, anything
675 * else will be bigger. All we need to do is define a string to this,
676 * and then take its size and compare to 3. If it's bigger, use
677 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
678 * let gcc optimize the rest.
681 #define trace_printk(fmt, ...) \
683 char _______STR[] = __stringify((__VA_ARGS__)); \
684 if (sizeof(_______STR) > 3) \
685 do_trace_printk(fmt, ##__VA_ARGS__); \
690 #define do_trace_printk(fmt, args...) \
692 static const char *trace_printk_fmt __used \
693 __attribute__((section("__trace_printk_fmt"))) = \
694 __builtin_constant_p(fmt) ? fmt : NULL; \
696 __trace_printk_check_format(fmt, ##args); \
698 if (__builtin_constant_p(fmt)) \
699 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
701 __trace_printk(_THIS_IP_, fmt, ##args); \
704 extern __printf(2, 3)
705 int __trace_bprintk(unsigned long ip
, const char *fmt
, ...);
707 extern __printf(2, 3)
708 int __trace_printk(unsigned long ip
, const char *fmt
, ...);
711 * trace_puts - write a string into the ftrace buffer
712 * @str: the string to record
714 * Note: __trace_bputs is an internal function for trace_puts and
715 * the @ip is passed in via the trace_puts macro.
717 * This is similar to trace_printk() but is made for those really fast
718 * paths that a developer wants the least amount of "Heisenbug" effects,
719 * where the processing of the print format is still too much.
721 * This function allows a kernel developer to debug fast path sections
722 * that printk is not appropriate for. By scattering in various
723 * printk like tracing in the code, a developer can quickly see
724 * where problems are occurring.
726 * This is intended as a debugging tool for the developer only.
727 * Please refrain from leaving trace_puts scattered around in
728 * your code. (Extra memory is used for special buffers that are
729 * allocated when trace_puts() is used.)
731 * Returns: 0 if nothing was written, positive # if string was.
732 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
735 #define trace_puts(str) ({ \
736 static const char *trace_printk_fmt __used \
737 __attribute__((section("__trace_printk_fmt"))) = \
738 __builtin_constant_p(str) ? str : NULL; \
740 if (__builtin_constant_p(str)) \
741 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
743 __trace_puts(_THIS_IP_, str, strlen(str)); \
745 extern int __trace_bputs(unsigned long ip
, const char *str
);
746 extern int __trace_puts(unsigned long ip
, const char *str
, int size
);
748 extern void trace_dump_stack(int skip
);
751 * The double __builtin_constant_p is because gcc will give us an error
752 * if we try to allocate the static variable to fmt if it is not a
753 * constant. Even with the outer if statement.
755 #define ftrace_vprintk(fmt, vargs) \
757 if (__builtin_constant_p(fmt)) { \
758 static const char *trace_printk_fmt __used \
759 __attribute__((section("__trace_printk_fmt"))) = \
760 __builtin_constant_p(fmt) ? fmt : NULL; \
762 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
764 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
767 extern __printf(2, 0) int
768 __ftrace_vbprintk(unsigned long ip
, const char *fmt
, va_list ap
);
770 extern __printf(2, 0) int
771 __ftrace_vprintk(unsigned long ip
, const char *fmt
, va_list ap
);
773 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
);
775 static inline void tracing_start(void) { }
776 static inline void tracing_stop(void) { }
777 static inline void trace_dump_stack(int skip
) { }
779 static inline void tracing_on(void) { }
780 static inline void tracing_off(void) { }
781 static inline int tracing_is_on(void) { return 0; }
782 static inline void tracing_snapshot(void) { }
783 static inline void tracing_snapshot_alloc(void) { }
785 static inline __printf(1, 2)
786 int trace_printk(const char *fmt
, ...)
790 static __printf(1, 0) inline int
791 ftrace_vprintk(const char *fmt
, va_list ap
)
795 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode
) { }
796 #endif /* CONFIG_TRACING */
799 * min()/max()/clamp() macros must accomplish three things:
801 * - avoid multiple evaluations of the arguments (so side-effects like
802 * "x++" happen only once) when non-constant.
803 * - perform strict type-checking (to generate warnings instead of
804 * nasty runtime surprises). See the "unnecessary" pointer comparison
806 * - retain result as a constant expressions when called with only
807 * constant expressions (to avoid tripping VLA warnings in stack
810 #define __typecheck(x, y) \
811 (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
814 * This returns a constant expression while determining if an argument is
815 * a constant expression, most importantly without evaluating the argument.
816 * Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
818 #define __is_constexpr(x) \
819 (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
821 #define __no_side_effects(x, y) \
822 (__is_constexpr(x) && __is_constexpr(y))
824 #define __safe_cmp(x, y) \
825 (__typecheck(x, y) && __no_side_effects(x, y))
827 #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
829 #define __cmp_once(x, y, unique_x, unique_y, op) ({ \
830 typeof(x) unique_x = (x); \
831 typeof(y) unique_y = (y); \
832 __cmp(unique_x, unique_y, op); })
834 #define __careful_cmp(x, y, op) \
835 __builtin_choose_expr(__safe_cmp(x, y), \
837 __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
840 * min - return minimum of two values of the same or compatible types
844 #define min(x, y) __careful_cmp(x, y, <)
847 * max - return maximum of two values of the same or compatible types
851 #define max(x, y) __careful_cmp(x, y, >)
854 * min3 - return minimum of three values
859 #define min3(x, y, z) min((typeof(x))min(x, y), z)
862 * max3 - return maximum of three values
867 #define max3(x, y, z) max((typeof(x))max(x, y), z)
870 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
874 #define min_not_zero(x, y) ({ \
875 typeof(x) __x = (x); \
876 typeof(y) __y = (y); \
877 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
880 * clamp - return a value clamped to a given range with strict typechecking
881 * @val: current value
882 * @lo: lowest allowable value
883 * @hi: highest allowable value
885 * This macro does strict typechecking of @lo/@hi to make sure they are of the
886 * same type as @val. See the unnecessary pointer comparisons.
888 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
891 * ..and if you can't take the strict
892 * types, you can specify one yourself.
894 * Or not use min/max/clamp at all, of course.
898 * min_t - return minimum of two values, using the specified type
899 * @type: data type to use
903 #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <)
906 * max_t - return maximum of two values, using the specified type
907 * @type: data type to use
911 #define max_t(type, x, y) __careful_cmp((type)(x), (type)(y), >)
914 * clamp_t - return a value clamped to a given range using a given type
915 * @type: the type of variable to use
916 * @val: current value
917 * @lo: minimum allowable value
918 * @hi: maximum allowable value
920 * This macro does no typechecking and uses temporary variables of type
921 * @type to make all the comparisons.
923 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
926 * clamp_val - return a value clamped to a given range using val's type
927 * @val: current value
928 * @lo: minimum allowable value
929 * @hi: maximum allowable value
931 * This macro does no typechecking and uses temporary variables of whatever
932 * type the input argument @val is. This is useful when @val is an unsigned
933 * type and @lo and @hi are literals that will otherwise be assigned a signed
936 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
940 * swap - swap values of @a and @b
945 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
947 /* This counts to 12. Any more, it will return 13th argument. */
948 #define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
949 #define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
951 #define __CONCAT(a, b) a ## b
952 #define CONCATENATE(a, b) __CONCAT(a, b)
955 * container_of - cast a member of a structure out to the containing structure
956 * @ptr: the pointer to the member.
957 * @type: the type of the container struct this is embedded in.
958 * @member: the name of the member within the struct.
961 #define container_of(ptr, type, member) ({ \
962 void *__mptr = (void *)(ptr); \
963 BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \
964 !__same_type(*(ptr), void), \
965 "pointer type mismatch in container_of()"); \
966 ((type *)(__mptr - offsetof(type, member))); })
968 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
969 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
970 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
973 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
974 #define VERIFY_OCTAL_PERMISSIONS(perms) \
975 (BUILD_BUG_ON_ZERO((perms) < 0) + \
976 BUILD_BUG_ON_ZERO((perms) > 0777) + \
977 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
978 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
979 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
980 /* USER_WRITABLE >= GROUP_WRITABLE */ \
981 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
982 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
983 BUILD_BUG_ON_ZERO((perms) & 2) + \