projects/linux·blob v4.8-rc2 · refs

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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 <asm/byteorder.h>
15#include <uapi/linux/kernel.h>
16
17#define USHRT_MAX ((u16)(~0U))
18#define SHRT_MAX ((s16)(USHRT_MAX>>1))
19#define SHRT_MIN ((s16)(-SHRT_MAX - 1))
20#define INT_MAX ((int)(~0U>>1))
21#define INT_MIN (-INT_MAX - 1)
22#define UINT_MAX (~0U)
23#define LONG_MAX ((long)(~0UL>>1))
24#define LONG_MIN (-LONG_MAX - 1)
25#define ULONG_MAX (~0UL)
26#define LLONG_MAX ((long long)(~0ULL>>1))
27#define LLONG_MIN (-LLONG_MAX - 1)
28#define ULLONG_MAX (~0ULL)
29#define SIZE_MAX (~(size_t)0)
30
31#define U8_MAX ((u8)~0U)
32#define S8_MAX ((s8)(U8_MAX>>1))
33#define S8_MIN ((s8)(-S8_MAX - 1))
34#define U16_MAX ((u16)~0U)
35#define S16_MAX ((s16)(U16_MAX>>1))
36#define S16_MIN ((s16)(-S16_MAX - 1))
37#define U32_MAX ((u32)~0U)
38#define S32_MAX ((s32)(U32_MAX>>1))
39#define S32_MIN ((s32)(-S32_MAX - 1))
40#define U64_MAX ((u64)~0ULL)
41#define S64_MAX ((s64)(U64_MAX>>1))
42#define S64_MIN ((s64)(-S64_MAX - 1))
43
44#define STACK_MAGIC 0xdeadbeef
45
46#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
47
48#define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
49#define __ALIGN_MASK(x, mask) __ALIGN_KERNEL_MASK((x), (mask))
50#define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned long)(p), (a)))
51#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
52
53#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
54
55#define u64_to_user_ptr(x) ( \
56{ \
57 typecheck(u64, x); \
58 (void __user *)(uintptr_t)x; \
59} \
60)
61
62/*
63 * This looks more complex than it should be. But we need to
64 * get the type for the ~ right in round_down (it needs to be
65 * as wide as the result!), and we want to evaluate the macro
66 * arguments just once each.
67 */
68#define __round_mask(x, y) ((__typeof__(x))((y)-1))
69#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
70#define round_down(x, y) ((x) & ~__round_mask(x, y))
71
72#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
73#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
74#define DIV_ROUND_UP_ULL(ll,d) \
75 ({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })
76
77#if BITS_PER_LONG == 32
78# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
79#else
80# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
81#endif
82
83/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
84#define roundup(x, y) ( \
85{ \
86 const typeof(y) __y = y; \
87 (((x) + (__y - 1)) / __y) * __y; \
88} \
89)
90#define rounddown(x, y) ( \
91{ \
92 typeof(x) __x = (x); \
93 __x - (__x % (y)); \
94} \
95)
96
97/*
98 * Divide positive or negative dividend by positive divisor and round
99 * to closest integer. Result is undefined for negative divisors and
100 * for negative dividends if the divisor variable type is unsigned.
101 */
102#define DIV_ROUND_CLOSEST(x, divisor)( \
103{ \
104 typeof(x) __x = x; \
105 typeof(divisor) __d = divisor; \
106 (((typeof(x))-1) > 0 || \
107 ((typeof(divisor))-1) > 0 || (__x) > 0) ? \
108 (((__x) + ((__d) / 2)) / (__d)) : \
109 (((__x) - ((__d) / 2)) / (__d)); \
110} \
111)
112/*
113 * Same as above but for u64 dividends. divisor must be a 32-bit
114 * number.
115 */
116#define DIV_ROUND_CLOSEST_ULL(x, divisor)( \
117{ \
118 typeof(divisor) __d = divisor; \
119 unsigned long long _tmp = (x) + (__d) / 2; \
120 do_div(_tmp, __d); \
121 _tmp; \
122} \
123)
124
125/*
126 * Multiplies an integer by a fraction, while avoiding unnecessary
127 * overflow or loss of precision.
128 */
129#define mult_frac(x, numer, denom)( \
130{ \
131 typeof(x) quot = (x) / (denom); \
132 typeof(x) rem = (x) % (denom); \
133 (quot * (numer)) + ((rem * (numer)) / (denom)); \
134} \
135)
136
137
138#define _RET_IP_ (unsigned long)__builtin_return_address(0)
139#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
140
141#ifdef CONFIG_LBDAF
142# include <asm/div64.h>
143# define sector_div(a, b) do_div(a, b)
144#else
145# define sector_div(n, b)( \
146{ \
147 int _res; \
148 _res = (n) % (b); \
149 (n) /= (b); \
150 _res; \
151} \
152)
153#endif
154
155/**
156 * upper_32_bits - return bits 32-63 of a number
157 * @n: the number we're accessing
158 *
159 * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress
160 * the "right shift count >= width of type" warning when that quantity is
161 * 32-bits.
162 */
163#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))
164
165/**
166 * lower_32_bits - return bits 0-31 of a number
167 * @n: the number we're accessing
168 */
169#define lower_32_bits(n) ((u32)(n))
170
171struct completion;
172struct pt_regs;
173struct user;
174
175#ifdef CONFIG_PREEMPT_VOLUNTARY
176extern int _cond_resched(void);
177# define might_resched() _cond_resched()
178#else
179# define might_resched() do { } while (0)
180#endif
181
182#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
183 void ___might_sleep(const char *file, int line, int preempt_offset);
184 void __might_sleep(const char *file, int line, int preempt_offset);
185/**
186 * might_sleep - annotation for functions that can sleep
187 *
188 * this macro will print a stack trace if it is executed in an atomic
189 * context (spinlock, irq-handler, ...).
190 *
191 * This is a useful debugging help to be able to catch problems early and not
192 * be bitten later when the calling function happens to sleep when it is not
193 * supposed to.
194 */
195# define might_sleep() \
196 do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
197# define sched_annotate_sleep() (current->task_state_change = 0)
198#else
199 static inline void ___might_sleep(const char *file, int line,
200 int preempt_offset) { }
201 static inline void __might_sleep(const char *file, int line,
202 int preempt_offset) { }
203# define might_sleep() do { might_resched(); } while (0)
204# define sched_annotate_sleep() do { } while (0)
205#endif
206
207#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
208
209/**
210 * abs - return absolute value of an argument
211 * @x: the value. If it is unsigned type, it is converted to signed type first.
212 * char is treated as if it was signed (regardless of whether it really is)
213 * but the macro's return type is preserved as char.
214 *
215 * Return: an absolute value of x.
216 */
217#define abs(x) __abs_choose_expr(x, long long, \
218 __abs_choose_expr(x, long, \
219 __abs_choose_expr(x, int, \
220 __abs_choose_expr(x, short, \
221 __abs_choose_expr(x, char, \
222 __builtin_choose_expr( \
223 __builtin_types_compatible_p(typeof(x), char), \
224 (char)({ signed char __x = (x); __x<0?-__x:__x; }), \
225 ((void)0)))))))
226
227#define __abs_choose_expr(x, type, other) __builtin_choose_expr( \
228 __builtin_types_compatible_p(typeof(x), signed type) || \
229 __builtin_types_compatible_p(typeof(x), unsigned type), \
230 ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)
231
232/**
233 * reciprocal_scale - "scale" a value into range [0, ep_ro)
234 * @val: value
235 * @ep_ro: right open interval endpoint
236 *
237 * Perform a "reciprocal multiplication" in order to "scale" a value into
238 * range [0, ep_ro), where the upper interval endpoint is right-open.
239 * This is useful, e.g. for accessing a index of an array containing
240 * ep_ro elements, for example. Think of it as sort of modulus, only that
241 * the result isn't that of modulo. ;) Note that if initial input is a
242 * small value, then result will return 0.
243 *
244 * Return: a result based on val in interval [0, ep_ro).
245 */
246static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
247{
248 return (u32)(((u64) val * ep_ro) >> 32);
249}
250
251#if defined(CONFIG_MMU) && \
252 (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
253#define might_fault() __might_fault(__FILE__, __LINE__)
254void __might_fault(const char *file, int line);
255#else
256static inline void might_fault(void) { }
257#endif
258
259extern struct atomic_notifier_head panic_notifier_list;
260extern long (*panic_blink)(int state);
261__printf(1, 2)
262void panic(const char *fmt, ...)
263 __noreturn __cold;
264void nmi_panic(struct pt_regs *regs, const char *msg);
265extern void oops_enter(void);
266extern void oops_exit(void);
267void print_oops_end_marker(void);
268extern int oops_may_print(void);
269void do_exit(long error_code)
270 __noreturn;
271void complete_and_exit(struct completion *, long)
272 __noreturn;
273
274/* Internal, do not use. */
275int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
276int __must_check _kstrtol(const char *s, unsigned int base, long *res);
277
278int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
279int __must_check kstrtoll(const char *s, unsigned int base, long long *res);
280
281/**
282 * kstrtoul - convert a string to an unsigned long
283 * @s: The start of the string. The string must be null-terminated, and may also
284 * include a single newline before its terminating null. The first character
285 * may also be a plus sign, but not a minus sign.
286 * @base: The number base to use. The maximum supported base is 16. If base is
287 * given as 0, then the base of the string is automatically detected with the
288 * conventional semantics - If it begins with 0x the number will be parsed as a
289 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
290 * parsed as an octal number. Otherwise it will be parsed as a decimal.
291 * @res: Where to write the result of the conversion on success.
292 *
293 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
294 * Used as a replacement for the obsolete simple_strtoull. Return code must
295 * be checked.
296*/
297static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
298{
299 /*
300 * We want to shortcut function call, but
301 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
302 */
303 if (sizeof(unsigned long) == sizeof(unsigned long long) &&
304 __alignof__(unsigned long) == __alignof__(unsigned long long))
305 return kstrtoull(s, base, (unsigned long long *)res);
306 else
307 return _kstrtoul(s, base, res);
308}
309
310/**
311 * kstrtol - convert a string to a long
312 * @s: The start of the string. The string must be null-terminated, and may also
313 * include a single newline before its terminating null. The first character
314 * may also be a plus sign or a minus sign.
315 * @base: The number base to use. The maximum supported base is 16. If base is
316 * given as 0, then the base of the string is automatically detected with the
317 * conventional semantics - If it begins with 0x the number will be parsed as a
318 * hexadecimal (case insensitive), if it otherwise begins with 0, it will be
319 * parsed as an octal number. Otherwise it will be parsed as a decimal.
320 * @res: Where to write the result of the conversion on success.
321 *
322 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
323 * Used as a replacement for the obsolete simple_strtoull. Return code must
324 * be checked.
325 */
326static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
327{
328 /*
329 * We want to shortcut function call, but
330 * __builtin_types_compatible_p(long, long long) = 0.
331 */
332 if (sizeof(long) == sizeof(long long) &&
333 __alignof__(long) == __alignof__(long long))
334 return kstrtoll(s, base, (long long *)res);
335 else
336 return _kstrtol(s, base, res);
337}
338
339int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
340int __must_check kstrtoint(const char *s, unsigned int base, int *res);
341
342static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
343{
344 return kstrtoull(s, base, res);
345}
346
347static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
348{
349 return kstrtoll(s, base, res);
350}
351
352static inline int __must_check kstrtou32(const char *s, unsigned int base, u32 *res)
353{
354 return kstrtouint(s, base, res);
355}
356
357static inline int __must_check kstrtos32(const char *s, unsigned int base, s32 *res)
358{
359 return kstrtoint(s, base, res);
360}
361
362int __must_check kstrtou16(const char *s, unsigned int base, u16 *res);
363int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
364int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
365int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
366int __must_check kstrtobool(const char *s, bool *res);
367
368int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
369int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
370int __must_check kstrtoul_from_user(const char __user *s, size_t count, unsigned int base, unsigned long *res);
371int __must_check kstrtol_from_user(const char __user *s, size_t count, unsigned int base, long *res);
372int __must_check kstrtouint_from_user(const char __user *s, size_t count, unsigned int base, unsigned int *res);
373int __must_check kstrtoint_from_user(const char __user *s, size_t count, unsigned int base, int *res);
374int __must_check kstrtou16_from_user(const char __user *s, size_t count, unsigned int base, u16 *res);
375int __must_check kstrtos16_from_user(const char __user *s, size_t count, unsigned int base, s16 *res);
376int __must_check kstrtou8_from_user(const char __user *s, size_t count, unsigned int base, u8 *res);
377int __must_check kstrtos8_from_user(const char __user *s, size_t count, unsigned int base, s8 *res);
378int __must_check kstrtobool_from_user(const char __user *s, size_t count, bool *res);
379
380static inline int __must_check kstrtou64_from_user(const char __user *s, size_t count, unsigned int base, u64 *res)
381{
382 return kstrtoull_from_user(s, count, base, res);
383}
384
385static inline int __must_check kstrtos64_from_user(const char __user *s, size_t count, unsigned int base, s64 *res)
386{
387 return kstrtoll_from_user(s, count, base, res);
388}
389
390static inline int __must_check kstrtou32_from_user(const char __user *s, size_t count, unsigned int base, u32 *res)
391{
392 return kstrtouint_from_user(s, count, base, res);
393}
394
395static inline int __must_check kstrtos32_from_user(const char __user *s, size_t count, unsigned int base, s32 *res)
396{
397 return kstrtoint_from_user(s, count, base, res);
398}
399
400/* Obsolete, do not use. Use kstrto<foo> instead */
401
402extern unsigned long simple_strtoul(const char *,char **,unsigned int);
403extern long simple_strtol(const char *,char **,unsigned int);
404extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
405extern long long simple_strtoll(const char *,char **,unsigned int);
406
407extern int num_to_str(char *buf, int size, unsigned long long num);
408
409/* lib/printf utilities */
410
411extern __printf(2, 3) int sprintf(char *buf, const char * fmt, ...);
412extern __printf(2, 0) int vsprintf(char *buf, const char *, va_list);
413extern __printf(3, 4)
414int snprintf(char *buf, size_t size, const char *fmt, ...);
415extern __printf(3, 0)
416int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
417extern __printf(3, 4)
418int scnprintf(char *buf, size_t size, const char *fmt, ...);
419extern __printf(3, 0)
420int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
421extern __printf(2, 3) __malloc
422char *kasprintf(gfp_t gfp, const char *fmt, ...);
423extern __printf(2, 0) __malloc
424char *kvasprintf(gfp_t gfp, const char *fmt, va_list args);
425extern __printf(2, 0)
426const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list args);
427
428extern __scanf(2, 3)
429int sscanf(const char *, const char *, ...);
430extern __scanf(2, 0)
431int vsscanf(const char *, const char *, va_list);
432
433extern int get_option(char **str, int *pint);
434extern char *get_options(const char *str, int nints, int *ints);
435extern unsigned long long memparse(const char *ptr, char **retptr);
436extern bool parse_option_str(const char *str, const char *option);
437
438extern int core_kernel_text(unsigned long addr);
439extern int core_kernel_data(unsigned long addr);
440extern int __kernel_text_address(unsigned long addr);
441extern int kernel_text_address(unsigned long addr);
442extern int func_ptr_is_kernel_text(void *ptr);
443
444unsigned long int_sqrt(unsigned long);
445
446extern void bust_spinlocks(int yes);
447extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */
448extern int panic_timeout;
449extern int panic_on_oops;
450extern int panic_on_unrecovered_nmi;
451extern int panic_on_io_nmi;
452extern int panic_on_warn;
453extern int sysctl_panic_on_rcu_stall;
454extern int sysctl_panic_on_stackoverflow;
455
456extern 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 */
463extern 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 */
470static 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}
475extern const char *print_tainted(void);
476enum lockdep_ok {
477 LOCKDEP_STILL_OK,
478 LOCKDEP_NOW_UNRELIABLE
479};
480extern void add_taint(unsigned flag, enum lockdep_ok);
481extern int test_taint(unsigned flag);
482extern unsigned long get_taint(void);
483extern int root_mountflags;
484
485extern bool early_boot_irqs_disabled;
486
487/* Values used for system_state */
488extern 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
513extern 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
517static 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
524extern 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
528static 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
535extern int hex_to_bin(char ch);
536extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
537extern char *bin2hex(char *dst, const void *src, size_t count);
538
539bool 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
561enum ftrace_dump_mode {
562 DUMP_NONE,
563 DUMP_ALL,
564 DUMP_ORIG,
565};
566
567#ifdef CONFIG_TRACING
568void tracing_on(void);
569void tracing_off(void);
570int tracing_is_on(void);
571void tracing_snapshot(void);
572void tracing_snapshot_alloc(void);
573
574extern void tracing_start(void);
575extern void tracing_stop(void);
576
577static inline __printf(1, 2)
578void ____trace_printk_check_format(const char *fmt, ...)
579{
580}
581#define __trace_printk_check_format(fmt, args...) \
582do { \
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, ...) \
618do { \
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...) \
627do { \
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
640extern __printf(2, 3)
641int __trace_bprintk(unsigned long ip, const char *fmt, ...);
642
643extern __printf(2, 3)
644int __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})
681extern int __trace_bputs(unsigned long ip, const char *str);
682extern int __trace_puts(unsigned long ip, const char *str, int size);
683
684extern 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) \
692do { \
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
703extern __printf(2, 0) int
704__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
705
706extern __printf(2, 0) int
707__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
708
709extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
710#else
711static inline void tracing_start(void) { }
712static inline void tracing_stop(void) { }
713static inline void trace_dump_stack(int skip) { }
714
715static inline void tracing_on(void) { }
716static inline void tracing_off(void) { }
717static inline int tracing_is_on(void) { return 0; }
718static inline void tracing_snapshot(void) { }
719static inline void tracing_snapshot_alloc(void) { }
720
721static inline __printf(1, 2)
722int trace_printk(const char *fmt, ...)
723{
724 return 0;
725}
726static __printf(1, 0) inline int
727ftrace_vprintk(const char *fmt, va_list ap)
728{
729 return 0;
730}
731static 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