1 #ifndef _LINUX_KERNEL_H
2 #define _LINUX_KERNEL_H
3
4
5 #include <stdarg.h>
6 #include <linux/linkage.h>
7 #include <linux/stddef.h>
8 #include <linux/types.h>
9 #include <linux/compiler.h>
10 #include <linux/bitops.h>
11 #include <linux/log2.h>
12 #include <linux/typecheck.h>
13 #include <linux/printk.h>
14 #include <linux/dynamic_debug.h>
15 #include <asm/byteorder.h>
16 #include <uapi/linux/kernel.h>
17
18 #define USHRT_MAX ((u16)(~0U))
19 #define SHRT_MAX ((s16)(USHRT_MAX>>1))
20 #define SHRT_MIN ((s16)(-SHRT_MAX - 1))
21 #define INT_MAX ((int)(~0U>>1))
22 #define INT_MIN (-INT_MAX - 1)
23 #define UINT_MAX (~0U)
24 #define LONG_MAX ((long)(~0UL>>1))
25 #define LONG_MIN (-LONG_MAX - 1)
26 #define ULONG_MAX (~0UL)
27 #define LLONG_MAX ((long long)(~0ULL>>1))
28 #define LLONG_MIN (-LLONG_MAX - 1)
29 #define ULLONG_MAX (~0ULL)
30 #define SIZE_MAX (~(size_t)0)
31
32 #define U8_MAX ((u8)~0U)
33 #define S8_MAX ((s8)(U8_MAX>>1))
34 #define S8_MIN ((s8)(-S8_MAX - 1))
35 #define U16_MAX ((u16)~0U)
36 #define S16_MAX ((s16)(U16_MAX>>1))
37 #define S16_MIN ((s16)(-S16_MAX - 1))
38 #define U32_MAX ((u32)~0U)
39 #define S32_MAX ((s32)(U32_MAX>>1))
40 #define S32_MIN ((s32)(-S32_MAX - 1))
41 #define U64_MAX ((u64)~0ULL)
42 #define S64_MAX ((s64)(U64_MAX>>1))
43 #define S64_MIN ((s64)(-S64_MAX - 1))
44
45 #define STACK_MAGIC 0xdeadbeef
46
47 #define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
48
49 #define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
50 #define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
51 #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
52 #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
53
54 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
55
56 #define u64_to_user_ptr(x) ( \
57 { \
58 typecheck(u64, x); \
59 (void __user *)(uintptr_t)x; \
60 } \
61 )
62
63 /*
64 * This looks more complex than it should be. But we need to
65 * get the type for the ~ right in round_down (it needs to be
66 * as wide as the result!), and we want to evaluate the macro
67 * arguments just once each.
68 */
69 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
70 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
71 #define round_down(x, y) ((x) & ~__round_mask(x, y))
72
73 #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
74 #define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
75 #define DIV_ROUND_UP_ULL(ll,d) \
76 ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
77
78 #if BITS_PER_LONG == 32
79 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
80 #else
81 # define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
82 #endif
83
84 /* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
85 #define roundup(x, y) ( \
86 { \
87 const typeof(y) __y = y; \
88 (((x) + (__y - 1)) / __y) * __y; \
89 } \
90 )
91 #define rounddown(x, y) ( \
92 { \
93 typeof(x) __x = (x); \
94 __x - (__x % (y)); \
95 } \
96 )
97
98 /*
99 * Divide positive or negative dividend by positive divisor and round
100 * to closest integer. Result is undefined for negative divisors and
101 * for negative dividends if the divisor variable type is unsigned.
102 */
103 #define DIV_ROUND_CLOSEST(x, divisor)( \
104 { \
105 typeof(x) __x = x; \
106 typeof(divisor) __d = divisor; \
107 (((typeof(x))-1) > 0 || \
108 ((typeof(divisor))-1) > 0 || (__x) > 0) ? \
109 (((__x) + ((__d) / 2)) / (__d)) : \
110 (((__x) - ((__d) / 2)) / (__d)); \
111 } \
112 )
113 /*
114 * Same as above but for u64 dividends. divisor must be a 32-bit
115 * number.
116 */
117 #define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
118 { \
119 typeof(divisor) __d = divisor; \
120 unsigned long long _tmp = (x) + (__d) / 2; \
121 do_div(_tmp, __d); \
122 _tmp; \
123 } \
124 )
125
126 /*
127 * Multiplies an integer by a fraction, while avoiding unnecessary
128 * overflow or loss of precision.
129 */
130 #define mult_frac(x, numer, denom)( \
131 { \
132 typeof(x) quot = (x) / (denom); \
133 typeof(x) rem = (x) % (denom); \
134 (quot * (numer)) + ((rem * (numer)) / (denom)); \
135 } \
136 )
137
138
139 #define _RET_IP_ (unsigned long)__builtin_return_address(0)
140 #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
141
142 #ifdef CONFIG_LBDAF
143 # include <asm/div64.h>
144 # define sector_div(a, b) do_div(a, b)
145 #else
146 # define sector_div(n, b)( \
147 { \
148 int _res; \
149 _res = (n) % (b); \
150 (n) /= (b); \
151 _res; \
152 } \
153 )
154 #endif
155
156 /**
157 * upper_32_bits - return bits 32-63 of a number
158 * @n: the number we're accessing
159 *
160 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
161 * the "right shift count >= width of type" warning when that quantity is
162 * 32-bits.
163 */
164 #define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
165
166 /**
167 * lower_32_bits - return bits 0-31 of a number
168 * @n: the number we're accessing
169 */
170 #define lower_32_bits(n) ((u32)(n))
171
172 struct completion;
173 struct pt_regs;
174 struct user;
175
176 #ifdef CONFIG_PREEMPT_VOLUNTARY
177 extern int _cond_resched(void);
178 # define might_resched() _cond_resched()
179 #else
180 # define might_resched() do { } while (0)
181 #endif
182
183 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
184 void ___might_sleep(const char *file, int line, int preempt_offset);
185 void __might_sleep(const char *file, int line, int preempt_offset);
186 /**
187 * might_sleep - annotation for functions that can sleep
188 *
189 * this macro will print a stack trace if it is executed in an atomic
190 * context (spinlock, irq-handler, ...).
191 *
192 * This is a useful debugging help to be able to catch problems early and not
193 * be bitten later when the calling function happens to sleep when it is not
194 * supposed to.
195 */
196 # define might_sleep() \
197 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
198 # define sched_annotate_sleep() (current->task_state_change = 0)
199 #else
200 static inline void ___might_sleep(const char *file, int line,
201 int preempt_offset) { }
202 static inline void __might_sleep(const char *file, int line,
203 int preempt_offset) { }
204 # define might_sleep() do { might_resched(); } while (0)
205 # define sched_annotate_sleep() do { } while (0)
206 #endif
207
208 #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
209
210 /**
211 * abs - return absolute value of an argument
212 * @x: the value. If it is unsigned type, it is converted to signed type first.
213 * char is treated as if it was signed (regardless of whether it really is)
214 * but the macro's return type is preserved as char.
215 *
216 * Return: an absolute value of x.
217 */
218 #define abs(x) __abs_choose_expr(x, long long, \
219 __abs_choose_expr(x, long, \
220 __abs_choose_expr(x, int, \
221 __abs_choose_expr(x, short, \
222 __abs_choose_expr(x, char, \
223 __builtin_choose_expr( \
224 __builtin_types_compatible_p(typeof(x), char), \
225 (char)({ signed char __x = (x); __x<0?-__x:__x; }), \
226 ((void)0)))))))
227
228 #define __abs_choose_expr(x, type, other) __builtin_choose_expr( \
229 __builtin_types_compatible_p(typeof(x), signed type) || \
230 __builtin_types_compatible_p(typeof(x), unsigned type), \
231 ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
232
233 /**
234 * reciprocal_scale - "scale" a value into range [0, ep_ro)
235 * @val: value
236 * @ep_ro: right open interval endpoint
237 *
238 * Perform a "reciprocal multiplication" in order to "scale" a value into
239 * range [0, ep_ro), where the upper interval endpoint is right-open.
240 * This is useful, e.g. for accessing a index of an array containing
241 * ep_ro elements, for example. Think of it as sort of modulus, only that
242 * the result isn't that of modulo. ;) Note that if initial input is a
243 * small value, then result will return 0.
244 *
245 * Return: a result based on val in interval [0, ep_ro).
246 */
247 static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
248 {
249 return (u32)(((u64) val * ep_ro) >> 32);
250 }
251
252 #if defined(CONFIG_MMU) && \
253 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
254 #define might_fault() __might_fault(__FILE__, __LINE__)
255 void __might_fault(const char *file, int line);
256 #else
257 static inline void might_fault(void) { }
258 #endif
259
260 extern struct atomic_notifier_head panic_notifier_list;
261 extern long (*panic_blink)(int state);
262 __printf(1, 2)
263 void panic(const char *fmt, ...)
264 __noreturn __cold;
265 void nmi_panic(struct pt_regs *regs, const char *msg);
266 extern void oops_enter(void);
267 extern void oops_exit(void);
268 void print_oops_end_marker(void);
269 extern int oops_may_print(void);
270 void do_exit(long error_code)
271 __noreturn;
272 void complete_and_exit(struct completion *, long)
273 __noreturn;
274
275 /* Internal, do not use. */
276 int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
277 int __must_check _kstrtol(const char *s, unsigned int base, long *res);
278
279 int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
280 int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
281
282 /**
283 * kstrtoul - convert a string to an unsigned long
284 * @s: The start of the string. The string must be null-terminated, and may also
285 * include a single newline before its terminating null. The first character
286 * may also be a plus sign, but not a minus sign.
287 * @base: The number base to use. The maximum supported base is 16. If base is
288 * given as 0, then the base of the string is automatically detected with the
289 * conventional semantics - If it begins with 0x the number will be parsed as a
290 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
291 * parsed as an octal number. Otherwise it will be parsed as a decimal.
292 * @res: Where to write the result of the conversion on success.
293 *
294 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
295 * Used as a replacement for the obsolete simple_strtoull. Return code must
296 * be checked.
297 */
298 static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
299 {
300 /*
301 * We want to shortcut function call, but
302 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
303 */
304 if (sizeof(unsigned long) == sizeof(unsigned long long) &&
305 __alignof__(unsigned long) == __alignof__(unsigned long long))
306 return kstrtoull(s, base, (unsigned long long *)res);
307 else
308 return _kstrtoul(s, base, res);
309 }
310
311 /**
312 * kstrtol - convert a string to a long
313 * @s: The start of the string. The string must be null-terminated, and may also
314 * include a single newline before its terminating null. The first character
315 * may also be a plus sign or a minus sign.
316 * @base: The number base to use. The maximum supported base is 16. If base is
317 * given as 0, then the base of the string is automatically detected with the
318 * conventional semantics - If it begins with 0x the number will be parsed as a
319 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
320 * parsed as an octal number. Otherwise it will be parsed as a decimal.
321 * @res: Where to write the result of the conversion on success.
322 *
323 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
324 * Used as a replacement for the obsolete simple_strtoull. Return code must
325 * be checked.
326 */
327 static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
328 {
329 /*
330 * We want to shortcut function call, but
331 * __builtin_types_compatible_p(long, long long) = 0.
332 */
333 if (sizeof(long) == sizeof(long long) &&
334 __alignof__(long) == __alignof__(long long))
335 return kstrtoll(s, base, (long long *)res);
336 else
337 return _kstrtol(s, base, res);
338 }
339
340 int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
341 int __must_check kstrtoint(const char *s, unsigned int base, int *res);
342
343 static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
344 {
345 return kstrtoull(s, base, res);
346 }
347
348 static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
349 {
350 return kstrtoll(s, base, res);
351 }
352
353 static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
354 {
355 return kstrtouint(s, base, res);
356 }
357
358 static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
359 {
360 return kstrtoint(s, base, res);
361 }
362
363 int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
364 int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
365 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
366 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
367 int __must_check kstrtobool(const char *s, bool *res);
368
369 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
370 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
371 int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
372 int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
373 int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
374 int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
375 int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
376 int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
377 int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
378 int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
379 int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
380
381 static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
382 {
383 return kstrtoull_from_user(s, count, base, res);
384 }
385
386 static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
387 {
388 return kstrtoll_from_user(s, count, base, res);
389 }
390
391 static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
392 {
393 return kstrtouint_from_user(s, count, base, res);
394 }
395
396 static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
397 {
398 return kstrtoint_from_user(s, count, base, res);
399 }
400
401 /* Obsolete, do not use. Use kstrto<foo> instead */
402
403 extern unsigned long simple_strtoul(const char *,char **,unsigned int);
404 extern long simple_strtol(const char *,char **,unsigned int);
405 extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
406 extern long long simple_strtoll(const char *,char **,unsigned int);
407
408 extern int num_to_str(char *buf, int size, unsigned long long num);
409
410 /* lib/printf utilities */
411
412 extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
413 extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
414 extern __printf(3, 4)
415 int snprintf(char *buf, size_t size, const char *fmt, ...);
416 extern __printf(3, 0)
417 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
418 extern __printf(3, 4)
419 int scnprintf(char *buf, size_t size, const char *fmt, ...);
420 extern __printf(3, 0)
421 int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
422 extern __printf(2, 3) __malloc
423 char *kasprintf(gfp_t gfp, const char *fmt, ...);
424 extern __printf(2, 0) __malloc
425 char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
426 extern __printf(2, 0)
427 const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
428
429 extern __scanf(2, 3)
430 int sscanf(const char *, const char *, ...);
431 extern __scanf(2, 0)
432 int vsscanf(const char *, const char *, va_list);
433
434 extern int get_option(char **str, int *pint);
435 extern char *get_options(const char *str, int nints, int *ints);
436 extern unsigned long long memparse(const char *ptr, char **retptr);
437 extern bool parse_option_str(const char *str, const char *option);
438
439 extern int core_kernel_text(unsigned long addr);
440 extern int core_kernel_data(unsigned long addr);
441 extern int __kernel_text_address(unsigned long addr);
442 extern int kernel_text_address(unsigned long addr);
443 extern int func_ptr_is_kernel_text(void *ptr);
444
445 unsigned long int_sqrt(unsigned long);
446
447 extern void bust_spinlocks(int yes);
448 extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
449 extern int panic_timeout;
450 extern int panic_on_oops;
451 extern int panic_on_unrecovered_nmi;
452 extern int panic_on_io_nmi;
453 extern int panic_on_warn;
454 extern int sysctl_panic_on_stackoverflow;
455
456 extern bool crash_kexec_post_notifiers;
457
458 /*
459 * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
460 * holds a CPU number which is executing panic() currently. A value of
461 * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
462 */
463 extern atomic_t panic_cpu;
464 #define PANIC_CPU_INVALID -1
465
466 /*
467 * Only to be used by arch init code. If the user over-wrote the default
468 * CONFIG_PANIC_TIMEOUT, honor it.
469 */
470 static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
471 {
472 if (panic_timeout == arch_default_timeout)
473 panic_timeout = timeout;
474 }
475 extern const char *print_tainted(void);
476 enum lockdep_ok {
477 LOCKDEP_STILL_OK,
478 LOCKDEP_NOW_UNRELIABLE
479 };
480 extern void add_taint(unsigned flag, enum lockdep_ok);
481 extern int test_taint(unsigned flag);
482 extern unsigned long get_taint(void);
483 extern int root_mountflags;
484
485 extern bool early_boot_irqs_disabled;
486
487 /* Values used for system_state */
488 extern enum system_states {
489 SYSTEM_BOOTING,
490 SYSTEM_RUNNING,
491 SYSTEM_HALT,
492 SYSTEM_POWER_OFF,
493 SYSTEM_RESTART,
494 } system_state;
495
496 #define TAINT_PROPRIETARY_MODULE 0
497 #define TAINT_FORCED_MODULE 1
498 #define TAINT_CPU_OUT_OF_SPEC 2
499 #define TAINT_FORCED_RMMOD 3
500 #define TAINT_MACHINE_CHECK 4
501 #define TAINT_BAD_PAGE 5
502 #define TAINT_USER 6
503 #define TAINT_DIE 7
504 #define TAINT_OVERRIDDEN_ACPI_TABLE 8
505 #define TAINT_WARN 9
506 #define TAINT_CRAP 10
507 #define TAINT_FIRMWARE_WORKAROUND 11
508 #define TAINT_OOT_MODULE 12
509 #define TAINT_UNSIGNED_MODULE 13
510 #define TAINT_SOFTLOCKUP 14
511 #define TAINT_LIVEPATCH 15
512
513 extern const char hex_asc[];
514 #define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
515 #define hex_asc_hi(x) hex_asc[((x) & 0xf0) >> 4]
516
517 static inline char *hex_byte_pack(char *buf, u8 byte)
518 {
519 *buf++ = hex_asc_hi(byte);
520 *buf++ = hex_asc_lo(byte);
521 return buf;
522 }
523
524 extern const char hex_asc_upper[];
525 #define hex_asc_upper_lo(x) hex_asc_upper[((x) & 0x0f)]
526 #define hex_asc_upper_hi(x) hex_asc_upper[((x) & 0xf0) >> 4]
527
528 static inline char *hex_byte_pack_upper(char *buf, u8 byte)
529 {
530 *buf++ = hex_asc_upper_hi(byte);
531 *buf++ = hex_asc_upper_lo(byte);
532 return buf;
533 }
534
535 extern int hex_to_bin(char ch);
536 extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
537 extern char *bin2hex(char *dst, const void *src, size_t count);
538
539 bool mac_pton(const char *s, u8 *mac);
540
541 /*
542 * General tracing related utility functions - trace_printk(),
543 * tracing_on/tracing_off and tracing_start()/tracing_stop
544 *
545 * Use tracing_on/tracing_off when you want to quickly turn on or off
546 * tracing. It simply enables or disables the recording of the trace events.
547 * This also corresponds to the user space /sys/kernel/debug/tracing/tracing_on
548 * file, which gives a means for the kernel and userspace to interact.
549 * Place a tracing_off() in the kernel where you want tracing to end.
550 * From user space, examine the trace, and then echo 1 > tracing_on
551 * to continue tracing.
552 *
553 * tracing_stop/tracing_start has slightly more overhead. It is used
554 * by things like suspend to ram where disabling the recording of the
555 * trace is not enough, but tracing must actually stop because things
556 * like calling smp_processor_id() may crash the system.
557 *
558 * Most likely, you want to use tracing_on/tracing_off.
559 */
560
561 enum ftrace_dump_mode {
562 DUMP_NONE,
563 DUMP_ALL,
564 DUMP_ORIG,
565 };
566
567 #ifdef CONFIG_TRACING
568 void tracing_on(void);
569 void tracing_off(void);
570 int tracing_is_on(void);
571 void tracing_snapshot(void);
572 void tracing_snapshot_alloc(void);
573
574 extern void tracing_start(void);
575 extern void tracing_stop(void);
576
577 static inline __printf(1, 2)
578 void ____trace_printk_check_format(const char *fmt, ...)
579 {
580 }
581 #define __trace_printk_check_format(fmt, args...) \
582 do { \
583 if (0) \
584 ____trace_printk_check_format(fmt, ##args); \
585 } while (0)
586
587 /**
588 * trace_printk - printf formatting in the ftrace buffer
589 * @fmt: the printf format for printing
590 *
591 * Note: __trace_printk is an internal function for trace_printk and
592 * the @ip is passed in via the trace_printk macro.
593 *
594 * This function allows a kernel developer to debug fast path sections
595 * that printk is not appropriate for. By scattering in various
596 * printk like tracing in the code, a developer can quickly see
597 * where problems are occurring.
598 *
599 * This is intended as a debugging tool for the developer only.
600 * Please refrain from leaving trace_printks scattered around in
601 * your code. (Extra memory is used for special buffers that are
602 * allocated when trace_printk() is used)
603 *
604 * A little optization trick is done here. If there's only one
605 * argument, there's no need to scan the string for printf formats.
606 * The trace_puts() will suffice. But how can we take advantage of
607 * using trace_puts() when trace_printk() has only one argument?
608 * By stringifying the args and checking the size we can tell
609 * whether or not there are args. __stringify((__VA_ARGS__)) will
610 * turn into "()\0" with a size of 3 when there are no args, anything
611 * else will be bigger. All we need to do is define a string to this,
612 * and then take its size and compare to 3. If it's bigger, use
613 * do_trace_printk() otherwise, optimize it to trace_puts(). Then just
614 * let gcc optimize the rest.
615 */
616
617 #define trace_printk(fmt, ...) \
618 do { \
619 char _______STR[] = __stringify((__VA_ARGS__)); \
620 if (sizeof(_______STR) > 3) \
621 do_trace_printk(fmt, ##__VA_ARGS__); \
622 else \
623 trace_puts(fmt); \
624 } while (0)
625
626 #define do_trace_printk(fmt, args...) \
627 do { \
628 static const char *trace_printk_fmt __used \
629 __attribute__((section("__trace_printk_fmt"))) = \
630 __builtin_constant_p(fmt) ? fmt : NULL; \
631 \
632 __trace_printk_check_format(fmt, ##args); \
633 \
634 if (__builtin_constant_p(fmt)) \
635 __trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
636 else \
637 __trace_printk(_THIS_IP_, fmt, ##args); \
638 } while (0)
639
640 extern __printf(2, 3)
641 int __trace_bprintk(unsigned long ip, const char *fmt, ...);
642
643 extern __printf(2, 3)
644 int __trace_printk(unsigned long ip, const char *fmt, ...);
645
646 /**
647 * trace_puts - write a string into the ftrace buffer
648 * @str: the string to record
649 *
650 * Note: __trace_bputs is an internal function for trace_puts and
651 * the @ip is passed in via the trace_puts macro.
652 *
653 * This is similar to trace_printk() but is made for those really fast
654 * paths that a developer wants the least amount of "Heisenbug" affects,
655 * where the processing of the print format is still too much.
656 *
657 * This function allows a kernel developer to debug fast path sections
658 * that printk is not appropriate for. By scattering in various
659 * printk like tracing in the code, a developer can quickly see
660 * where problems are occurring.
661 *
662 * This is intended as a debugging tool for the developer only.
663 * Please refrain from leaving trace_puts scattered around in
664 * your code. (Extra memory is used for special buffers that are
665 * allocated when trace_puts() is used)
666 *
667 * Returns: 0 if nothing was written, positive # if string was.
668 * (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
669 */
670
671 #define trace_puts(str) ({ \
672 static const char *trace_printk_fmt __used \
673 __attribute__((section("__trace_printk_fmt"))) = \
674 __builtin_constant_p(str) ? str : NULL; \
675 \
676 if (__builtin_constant_p(str)) \
677 __trace_bputs(_THIS_IP_, trace_printk_fmt); \
678 else \
679 __trace_puts(_THIS_IP_, str, strlen(str)); \
680 })
681 extern int __trace_bputs(unsigned long ip, const char *str);
682 extern int __trace_puts(unsigned long ip, const char *str, int size);
683
684 extern void trace_dump_stack(int skip);
685
686 /*
687 * The double __builtin_constant_p is because gcc will give us an error
688 * if we try to allocate the static variable to fmt if it is not a
689 * constant. Even with the outer if statement.
690 */
691 #define ftrace_vprintk(fmt, vargs) \
692 do { \
693 if (__builtin_constant_p(fmt)) { \
694 static const char *trace_printk_fmt __used \
695 __attribute__((section("__trace_printk_fmt"))) = \
696 __builtin_constant_p(fmt) ? fmt : NULL; \
697 \
698 __ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
699 } else \
700 __ftrace_vprintk(_THIS_IP_, fmt, vargs); \
701 } while (0)
702
703 extern __printf(2, 0) int
704 __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
705
706 extern __printf(2, 0) int
707 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
708
709 extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
710 #else
711 static inline void tracing_start(void) { }
712 static inline void tracing_stop(void) { }
713 static inline void trace_dump_stack(int skip) { }
714
715 static inline void tracing_on(void) { }
716 static inline void tracing_off(void) { }
717 static inline int tracing_is_on(void) { return 0; }
718 static inline void tracing_snapshot(void) { }
719 static inline void tracing_snapshot_alloc(void) { }
720
721 static inline __printf(1, 2)
722 int trace_printk(const char *fmt, ...)
723 {
724 return 0;
725 }
726 static __printf(1, 0) inline int
727 ftrace_vprintk(const char *fmt, va_list ap)
728 {
729 return 0;
730 }
731 static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
732 #endif /* CONFIG_TRACING */
733
734 /*
735 * min()/max()/clamp() macros that also do
736 * strict type-checking.. See the
737 * "unnecessary" pointer comparison.
738 */
739 #define min(x, y) ({ \
740 typeof(x) _min1 = (x); \
741 typeof(y) _min2 = (y); \
742 (void) (&_min1 == &_min2); \
743 _min1 < _min2 ? _min1 : _min2; })
744
745 #define max(x, y) ({ \
746 typeof(x) _max1 = (x); \
747 typeof(y) _max2 = (y); \
748 (void) (&_max1 == &_max2); \
749 _max1 > _max2 ? _max1 : _max2; })
750
751 #define min3(x, y, z) min((typeof(x))min(x, y), z)
752 #define max3(x, y, z) max((typeof(x))max(x, y), z)
753
754 /**
755 * min_not_zero - return the minimum that is _not_ zero, unless both are zero
756 * @x: value1
757 * @y: value2
758 */
759 #define min_not_zero(x, y) ({ \
760 typeof(x) __x = (x); \
761 typeof(y) __y = (y); \
762 __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
763
764 /**
765 * clamp - return a value clamped to a given range with strict typechecking
766 * @val: current value
767 * @lo: lowest allowable value
768 * @hi: highest allowable value
769 *
770 * This macro does strict typechecking of lo/hi to make sure they are of the
771 * same type as val. See the unnecessary pointer comparisons.
772 */
773 #define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
774
775 /*
776 * ..and if you can't take the strict
777 * types, you can specify one yourself.
778 *
779 * Or not use min/max/clamp at all, of course.
780 */
781 #define min_t(type, x, y) ({ \
782 type __min1 = (x); \
783 type __min2 = (y); \
784 __min1 < __min2 ? __min1: __min2; })
785
786 #define max_t(type, x, y) ({ \
787 type __max1 = (x); \
788 type __max2 = (y); \
789 __max1 > __max2 ? __max1: __max2; })
790
791 /**
792 * clamp_t - return a value clamped to a given range using a given type
793 * @type: the type of variable to use
794 * @val: current value
795 * @lo: minimum allowable value
796 * @hi: maximum allowable value
797 *
798 * This macro does no typechecking and uses temporary variables of type
799 * 'type' to make all the comparisons.
800 */
801 #define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
802
803 /**
804 * clamp_val - return a value clamped to a given range using val's type
805 * @val: current value
806 * @lo: minimum allowable value
807 * @hi: maximum allowable value
808 *
809 * This macro does no typechecking and uses temporary variables of whatever
810 * type the input argument 'val' is. This is useful when val is an unsigned
811 * type and min and max are literals that will otherwise be assigned a signed
812 * integer type.
813 */
814 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
815
816
817 /*
818 * swap - swap value of @a and @b
819 */
820 #define swap(a, b) \
821 do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
822
823 /**
824 * container_of - cast a member of a structure out to the containing structure
825 * @ptr: the pointer to the member.
826 * @type: the type of the container struct this is embedded in.
827 * @member: the name of the member within the struct.
828 *
829 */
830 #define container_of(ptr, type, member) ({ \
831 const typeof( ((type *)0)->member ) *__mptr = (ptr); \
832 (type *)( (char *)__mptr - offsetof(type,member) );})
833
834 /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
835 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
836 # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
837 #endif
838
839 /* Permissions on a sysfs file: you didn't miss the 0 prefix did you? */
840 #define VERIFY_OCTAL_PERMISSIONS(perms) \
841 (BUILD_BUG_ON_ZERO((perms) < 0) + \
842 BUILD_BUG_ON_ZERO((perms) > 0777) + \
843 /* USER_READABLE >= GROUP_READABLE >= OTHER_READABLE */ \
844 BUILD_BUG_ON_ZERO((((perms) >> 6) & 4) < (((perms) >> 3) & 4)) + \
845 BUILD_BUG_ON_ZERO((((perms) >> 3) & 4) < ((perms) & 4)) + \
846 /* USER_WRITABLE >= GROUP_WRITABLE */ \
847 BUILD_BUG_ON_ZERO((((perms) >> 6) & 2) < (((perms) >> 3) & 2)) + \
848 /* OTHER_WRITABLE? Generally considered a bad idea. */ \
849 BUILD_BUG_ON_ZERO((perms) & 2) + \
850 (perms))
851 #endif
852
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