1 /*-
2  * Copyright (c) 2010 Isilon Systems, Inc.
3  * Copyright (c) 2010 iX Systems, Inc.
4  * Copyright (c) 2010 Panasas, Inc.
5  * Copyright (c) 2013-2016 Mellanox Technologies, Ltd.
6  * Copyright (c) 2014-2015 François Tigeot
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice unmodified, this list of conditions, and the following
14  *    disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  *
30  * $FreeBSD$
31  */
32 #ifndef	_LINUX_KERNEL_H_
33 #define	_LINUX_KERNEL_H_
34 
35 #include <sys/cdefs.h>
36 #include <sys/types.h>
37 #include <sys/systm.h>
38 #include <sys/param.h>
39 #include <sys/libkern.h>
40 #include <sys/stat.h>
41 #include <sys/smp.h>
42 #include <sys/stddef.h>
43 #include <sys/syslog.h>
44 #include <sys/time.h>
45 
46 #include <linux/bitops.h>
47 #include <linux/compiler.h>
48 #include <linux/errno.h>
49 #include <linux/sched.h>
50 #include <linux/types.h>
51 #include <linux/jiffies.h>
52 #include <linux/log2.h>
53 
54 #include <asm/byteorder.h>
55 #include <asm/uaccess.h>
56 
57 #include <machine/stdarg.h>
58 
59 #define KERN_CONT       ""
60 #define	KERN_EMERG	"<0>"
61 #define	KERN_ALERT	"<1>"
62 #define	KERN_CRIT	"<2>"
63 #define	KERN_ERR	"<3>"
64 #define	KERN_WARNING	"<4>"
65 #define	KERN_NOTICE	"<5>"
66 #define	KERN_INFO	"<6>"
67 #define	KERN_DEBUG	"<7>"
68 
69 #define	U8_MAX		((u8)~0U)
70 #define	S8_MAX		((s8)(U8_MAX >> 1))
71 #define	S8_MIN		((s8)(-S8_MAX - 1))
72 #define	U16_MAX		((u16)~0U)
73 #define	S16_MAX		((s16)(U16_MAX >> 1))
74 #define	S16_MIN		((s16)(-S16_MAX - 1))
75 #define	U32_MAX		((u32)~0U)
76 #define	S32_MAX		((s32)(U32_MAX >> 1))
77 #define	S32_MIN		((s32)(-S32_MAX - 1))
78 #define	U64_MAX		((u64)~0ULL)
79 #define	S64_MAX		((s64)(U64_MAX >> 1))
80 #define	S64_MIN		((s64)(-S64_MAX - 1))
81 
82 #define	S8_C(x)  x
83 #define	U8_C(x)  x ## U
84 #define	S16_C(x) x
85 #define	U16_C(x) x ## U
86 #define	S32_C(x) x
87 #define	U32_C(x) x ## U
88 #define	S64_C(x) x ## LL
89 #define	U64_C(x) x ## ULL
90 
91 #define	BUILD_BUG()			do { CTASSERT(0); } while (0)
92 #define	BUILD_BUG_ON(x)			CTASSERT(!(x))
93 #define	BUILD_BUG_ON_MSG(x, msg)	BUILD_BUG_ON(x)
94 #define	BUILD_BUG_ON_NOT_POWER_OF_2(x)	BUILD_BUG_ON(!powerof2(x))
95 #define	BUILD_BUG_ON_INVALID(expr)	while (0) { (void)(expr); }
96 
97 extern const volatile int lkpi_build_bug_on_zero;
98 #define	BUILD_BUG_ON_ZERO(x)	((x) ? lkpi_build_bug_on_zero : 0)
99 
100 #define	BUG()			panic("BUG at %s:%d", __FILE__, __LINE__)
101 #define	BUG_ON(cond)		do {				\
102 	if (cond) {						\
103 		panic("BUG ON %s failed at %s:%d",		\
104 		    __stringify(cond), __FILE__, __LINE__);	\
105 	}							\
106 } while (0)
107 
108 #define	WARN_ON(cond) ({					\
109       bool __ret = (cond);					\
110       if (__ret) {						\
111 		printf("WARNING %s failed at %s:%d\n",		\
112 		    __stringify(cond), __FILE__, __LINE__);	\
113 		linux_dump_stack();				\
114       }								\
115       unlikely(__ret);						\
116 })
117 
118 #define	WARN_ON_SMP(cond)	WARN_ON(cond)
119 
120 #define	WARN_ON_ONCE(cond) ({					\
121       static bool __warn_on_once;				\
122       bool __ret = (cond);					\
123       if (__ret && !__warn_on_once) {				\
124 		__warn_on_once = 1;				\
125 		printf("WARNING %s failed at %s:%d\n",		\
126 		    __stringify(cond), __FILE__, __LINE__);	\
127 		linux_dump_stack();				\
128       }								\
129       unlikely(__ret);						\
130 })
131 
132 #define	oops_in_progress	SCHEDULER_STOPPED()
133 
134 #undef	ALIGN
135 #define	ALIGN(x, y)		roundup2((x), (y))
136 #undef PTR_ALIGN
137 #define	PTR_ALIGN(p, a)		((__typeof(p))ALIGN((uintptr_t)(p), (a)))
138 #define	IS_ALIGNED(x, a)	(((x) & ((__typeof(x))(a) - 1)) == 0)
139 #define	DIV_ROUND_UP(x, n)	howmany(x, n)
140 #define	__KERNEL_DIV_ROUND_UP(x, n)	howmany(x, n)
141 #define	DIV_ROUND_UP_ULL(x, n)	DIV_ROUND_UP((unsigned long long)(x), (n))
142 #define	DIV_ROUND_DOWN_ULL(x, n) (((unsigned long long)(x) / (n)) * (n))
143 #define	FIELD_SIZEOF(t, f)	sizeof(((t *)0)->f)
144 
145 #define	printk(...)		printf(__VA_ARGS__)
146 #define	vprintk(f, a)		vprintf(f, a)
147 
148 #define	asm			__asm
149 
150 extern void linux_dump_stack(void);
151 #define	dump_stack()		linux_dump_stack()
152 
153 struct va_format {
154 	const char *fmt;
155 	va_list *va;
156 };
157 
158 static inline int
159 vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
160 {
161 	ssize_t ssize = size;
162 	int i;
163 
164 	i = vsnprintf(buf, size, fmt, args);
165 
166 	return ((i >= ssize) ? (ssize - 1) : i);
167 }
168 
169 static inline int
170 scnprintf(char *buf, size_t size, const char *fmt, ...)
171 {
172 	va_list args;
173 	int i;
174 
175 	va_start(args, fmt);
176 	i = vscnprintf(buf, size, fmt, args);
177 	va_end(args);
178 
179 	return (i);
180 }
181 
182 /*
183  * The "pr_debug()" and "pr_devel()" macros should produce zero code
184  * unless DEBUG is defined:
185  */
186 #ifdef DEBUG
187 extern int linuxkpi_debug;
188 #define pr_debug(fmt, ...)					\
189 	do {							\
190 		if (linuxkpi_debug)				\
191 			log(LOG_DEBUG, fmt, ##__VA_ARGS__);	\
192 	} while (0)
193 #define pr_devel(fmt, ...) \
194 	log(LOG_DEBUG, pr_fmt(fmt), ##__VA_ARGS__)
195 #else
196 #define pr_debug(fmt, ...) \
197 	({ if (0) log(LOG_DEBUG, fmt, ##__VA_ARGS__); 0; })
198 #define pr_devel(fmt, ...) \
199 	({ if (0) log(LOG_DEBUG, pr_fmt(fmt), ##__VA_ARGS__); 0; })
200 #endif
201 
202 #ifndef pr_fmt
203 #define pr_fmt(fmt) fmt
204 #endif
205 
206 /*
207  * Print a one-time message (analogous to WARN_ONCE() et al):
208  */
209 #define printk_once(...) do {			\
210 	static bool __print_once;		\
211 						\
212 	if (!__print_once) {			\
213 		__print_once = true;		\
214 		printk(__VA_ARGS__);		\
215 	}					\
216 } while (0)
217 
218 /*
219  * Log a one-time message (analogous to WARN_ONCE() et al):
220  */
221 #define log_once(level,...) do {		\
222 	static bool __log_once;			\
223 						\
224 	if (unlikely(!__log_once)) {		\
225 		__log_once = true;		\
226 		log(level, __VA_ARGS__);	\
227 	}					\
228 } while (0)
229 
230 #define pr_emerg(fmt, ...) \
231 	log(LOG_EMERG, pr_fmt(fmt), ##__VA_ARGS__)
232 #define pr_alert(fmt, ...) \
233 	log(LOG_ALERT, pr_fmt(fmt), ##__VA_ARGS__)
234 #define pr_crit(fmt, ...) \
235 	log(LOG_CRIT, pr_fmt(fmt), ##__VA_ARGS__)
236 #define pr_err(fmt, ...) \
237 	log(LOG_ERR, pr_fmt(fmt), ##__VA_ARGS__)
238 #define pr_err_once(fmt, ...) \
239 	log_once(LOG_ERR, pr_fmt(fmt), ##__VA_ARGS__)
240 #define pr_warning(fmt, ...) \
241 	log(LOG_WARNING, pr_fmt(fmt), ##__VA_ARGS__)
242 #define pr_warn(...) \
243 	pr_warning(__VA_ARGS__)
244 #define pr_warn_once(fmt, ...) \
245 	log_once(LOG_WARNING, pr_fmt(fmt), ##__VA_ARGS__)
246 #define pr_notice(fmt, ...) \
247 	log(LOG_NOTICE, pr_fmt(fmt), ##__VA_ARGS__)
248 #define pr_info(fmt, ...) \
249 	log(LOG_INFO, pr_fmt(fmt), ##__VA_ARGS__)
250 #define pr_info_once(fmt, ...) \
251 	log_once(LOG_INFO, pr_fmt(fmt), ##__VA_ARGS__)
252 #define pr_cont(fmt, ...) \
253 	printk(KERN_CONT fmt, ##__VA_ARGS__)
254 #define	pr_warn_ratelimited(...) do {		\
255 	static linux_ratelimit_t __ratelimited;	\
256 	if (linux_ratelimited(&__ratelimited))	\
257 		pr_warning(__VA_ARGS__);	\
258 } while (0)
259 
260 #ifndef WARN
261 #define	WARN(condition, ...) ({			\
262 	bool __ret_warn_on = (condition);	\
263 	if (unlikely(__ret_warn_on))		\
264 		pr_warning(__VA_ARGS__);	\
265 	unlikely(__ret_warn_on);		\
266 })
267 #endif
268 
269 #ifndef WARN_ONCE
270 #define	WARN_ONCE(condition, ...) ({		\
271 	bool __ret_warn_on = (condition);	\
272 	if (unlikely(__ret_warn_on))		\
273 		pr_warn_once(__VA_ARGS__);	\
274 	unlikely(__ret_warn_on);		\
275 })
276 #endif
277 
278 #define container_of(ptr, type, member)				\
279 ({								\
280 	const __typeof(((type *)0)->member) *__p = (ptr);	\
281 	(type *)((uintptr_t)__p - offsetof(type, member));	\
282 })
283 
284 #define	ARRAY_SIZE(x)	(sizeof(x) / sizeof((x)[0]))
285 
286 #define	u64_to_user_ptr(val)	((void *)(uintptr_t)(val))
287 
288 #define _RET_IP_		__builtin_return_address(0)
289 
290 static inline unsigned long long
291 simple_strtoull(const char *cp, char **endp, unsigned int base)
292 {
293 	return (strtouq(cp, endp, base));
294 }
295 
296 static inline long long
297 simple_strtoll(const char *cp, char **endp, unsigned int base)
298 {
299 	return (strtoq(cp, endp, base));
300 }
301 
302 static inline unsigned long
303 simple_strtoul(const char *cp, char **endp, unsigned int base)
304 {
305 	return (strtoul(cp, endp, base));
306 }
307 
308 static inline long
309 simple_strtol(const char *cp, char **endp, unsigned int base)
310 {
311 	return (strtol(cp, endp, base));
312 }
313 
314 static inline int
315 kstrtoul(const char *cp, unsigned int base, unsigned long *res)
316 {
317 	char *end;
318 
319 	*res = strtoul(cp, &end, base);
320 
321 	/* skip newline character, if any */
322 	if (*end == '\n')
323 		end++;
324 	if (*cp == 0 || *end != 0)
325 		return (-EINVAL);
326 	return (0);
327 }
328 
329 static inline int
330 kstrtol(const char *cp, unsigned int base, long *res)
331 {
332 	char *end;
333 
334 	*res = strtol(cp, &end, base);
335 
336 	/* skip newline character, if any */
337 	if (*end == '\n')
338 		end++;
339 	if (*cp == 0 || *end != 0)
340 		return (-EINVAL);
341 	return (0);
342 }
343 
344 static inline int
345 kstrtoint(const char *cp, unsigned int base, int *res)
346 {
347 	char *end;
348 	long temp;
349 
350 	*res = temp = strtol(cp, &end, base);
351 
352 	/* skip newline character, if any */
353 	if (*end == '\n')
354 		end++;
355 	if (*cp == 0 || *end != 0)
356 		return (-EINVAL);
357 	if (temp != (int)temp)
358 		return (-ERANGE);
359 	return (0);
360 }
361 
362 static inline int
363 kstrtouint(const char *cp, unsigned int base, unsigned int *res)
364 {
365 	char *end;
366 	unsigned long temp;
367 
368 	*res = temp = strtoul(cp, &end, base);
369 
370 	/* skip newline character, if any */
371 	if (*end == '\n')
372 		end++;
373 	if (*cp == 0 || *end != 0)
374 		return (-EINVAL);
375 	if (temp != (unsigned int)temp)
376 		return (-ERANGE);
377 	return (0);
378 }
379 
380 static inline int
381 kstrtou16(const char *cp, unsigned int base, u16 *res)
382 {
383 	char *end;
384 	unsigned long temp;
385 
386 	*res = temp = strtoul(cp, &end, base);
387 
388 	/* skip newline character, if any */
389 	if (*end == '\n')
390 		end++;
391 	if (*cp == 0 || *end != 0)
392 		return (-EINVAL);
393 	if (temp != (u16)temp)
394 		return (-ERANGE);
395 	return (0);
396 }
397 
398 static inline int
399 kstrtou32(const char *cp, unsigned int base, u32 *res)
400 {
401 	char *end;
402 	unsigned long temp;
403 
404 	*res = temp = strtoul(cp, &end, base);
405 
406 	/* skip newline character, if any */
407 	if (*end == '\n')
408 		end++;
409 	if (*cp == 0 || *end != 0)
410 		return (-EINVAL);
411 	if (temp != (u32)temp)
412 		return (-ERANGE);
413 	return (0);
414 }
415 
416 static inline int
417 kstrtou64(const char *cp, unsigned int base, u64 *res)
418 {
419        char *end;
420 
421        *res = strtouq(cp, &end, base);
422 
423        /* skip newline character, if any */
424        if (*end == '\n')
425                end++;
426        if (*cp == 0 || *end != 0)
427                return (-EINVAL);
428        return (0);
429 }
430 
431 static inline int
432 kstrtobool(const char *s, bool *res)
433 {
434 	int len;
435 
436 	if (s == NULL || (len = strlen(s)) == 0 || res == NULL)
437 		return (-EINVAL);
438 
439 	/* skip newline character, if any */
440 	if (s[len - 1] == '\n')
441 		len--;
442 
443 	if (len == 1 && strchr("yY1", s[0]) != NULL)
444 		*res = true;
445 	else if (len == 1 && strchr("nN0", s[0]) != NULL)
446 		*res = false;
447 	else if (strncasecmp("on", s, len) == 0)
448 		*res = true;
449 	else if (strncasecmp("off", s, len) == 0)
450 		*res = false;
451 	else
452 		return (-EINVAL);
453 
454 	return (0);
455 }
456 
457 static inline int
458 kstrtobool_from_user(const char __user *s, size_t count, bool *res)
459 {
460 	char buf[8] = {};
461 
462 	if (count > (sizeof(buf) - 1))
463 		count = (sizeof(buf) - 1);
464 
465 	if (copy_from_user(buf, s, count))
466 		return (-EFAULT);
467 
468 	return (kstrtobool(buf, res));
469 }
470 
471 #define min(x, y)	((x) < (y) ? (x) : (y))
472 #define max(x, y)	((x) > (y) ? (x) : (y))
473 
474 #define min3(a, b, c)	min(a, min(b,c))
475 #define max3(a, b, c)	max(a, max(b,c))
476 
477 #define	min_t(type, x, y) ({			\
478 	type __min1 = (x);			\
479 	type __min2 = (y);			\
480 	__min1 < __min2 ? __min1 : __min2; })
481 
482 #define	max_t(type, x, y) ({			\
483 	type __max1 = (x);			\
484 	type __max2 = (y);			\
485 	__max1 > __max2 ? __max1 : __max2; })
486 
487 #define offsetofend(t, m)	\
488         (offsetof(t, m) + sizeof((((t *)0)->m)))
489 
490 #define clamp_t(type, _x, min, max)	min_t(type, max_t(type, _x, min), max)
491 #define clamp(x, lo, hi)		min( max(x,lo), hi)
492 #define	clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
493 
494 /*
495  * This looks more complex than it should be. But we need to
496  * get the type for the ~ right in round_down (it needs to be
497  * as wide as the result!), and we want to evaluate the macro
498  * arguments just once each.
499  */
500 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
501 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
502 #define round_down(x, y) ((x) & ~__round_mask(x, y))
503 
504 #define	smp_processor_id()	PCPU_GET(cpuid)
505 #define	num_possible_cpus()	mp_ncpus
506 #define	num_online_cpus()	mp_ncpus
507 
508 #if defined(__i386__) || defined(__amd64__)
509 extern bool linux_cpu_has_clflush;
510 #define	cpu_has_clflush		linux_cpu_has_clflush
511 #endif
512 
513 typedef struct pm_message {
514 	int event;
515 } pm_message_t;
516 
517 /* Swap values of a and b */
518 #define swap(a, b) do {			\
519 	typeof(a) _swap_tmp = a;	\
520 	a = b;				\
521 	b = _swap_tmp;			\
522 } while (0)
523 
524 #define	DIV_ROUND_CLOSEST(x, divisor)	(((x) + ((divisor) / 2)) / (divisor))
525 
526 #define	DIV_ROUND_CLOSEST_ULL(x, divisor) ({		\
527 	__typeof(divisor) __d = (divisor);		\
528 	unsigned long long __ret = (x) + (__d) / 2;	\
529 	__ret /= __d;					\
530 	__ret;						\
531 })
532 
533 static inline uintmax_t
534 mult_frac(uintmax_t x, uintmax_t multiplier, uintmax_t divisor)
535 {
536 	uintmax_t q = (x / divisor);
537 	uintmax_t r = (x % divisor);
538 
539 	return ((q * multiplier) + ((r * multiplier) / divisor));
540 }
541 
542 static inline int64_t
543 abs64(int64_t x)
544 {
545 	return (x < 0 ? -x : x);
546 }
547 
548 typedef struct linux_ratelimit {
549 	struct timeval lasttime;
550 	int counter;
551 } linux_ratelimit_t;
552 
553 static inline bool
554 linux_ratelimited(linux_ratelimit_t *rl)
555 {
556 	return (ppsratecheck(&rl->lasttime, &rl->counter, 1));
557 }
558 
559 #define	struct_size(ptr, field, num) ({ \
560 	const size_t __size = offsetof(__typeof(*(ptr)), field); \
561 	const size_t __max = (SIZE_MAX - __size) / sizeof((ptr)->field[0]); \
562 	((num) > __max) ? SIZE_MAX : (__size + sizeof((ptr)->field[0]) * (num)); \
563 })
564 
565 #define	__is_constexpr(x) \
566 	__builtin_constant_p(x)
567 
568 /*
569  * The is_signed() macro below returns true if the passed data type is
570  * signed. Else false is returned.
571  */
572 #define	is_signed(datatype) (((datatype)-1 / (datatype)2) == (datatype)0)
573 
574 /*
575  * The type_max() macro below returns the maxium positive value the
576  * passed data type can hold.
577  */
578 #define	type_max(datatype) ( \
579   (sizeof(datatype) >= 8) ? (is_signed(datatype) ? INT64_MAX : UINT64_MAX) : \
580   (sizeof(datatype) >= 4) ? (is_signed(datatype) ? INT32_MAX : UINT32_MAX) : \
581   (sizeof(datatype) >= 2) ? (is_signed(datatype) ? INT16_MAX : UINT16_MAX) : \
582 			    (is_signed(datatype) ? INT8_MAX : UINT8_MAX) \
583 )
584 
585 /*
586  * The type_min() macro below returns the minimum value the passed
587  * data type can hold. For unsigned types the minimum value is always
588  * zero. For signed types it may vary.
589  */
590 #define	type_min(datatype) ( \
591   (sizeof(datatype) >= 8) ? (is_signed(datatype) ? INT64_MIN : 0) : \
592   (sizeof(datatype) >= 4) ? (is_signed(datatype) ? INT32_MIN : 0) : \
593   (sizeof(datatype) >= 2) ? (is_signed(datatype) ? INT16_MIN : 0) : \
594 			    (is_signed(datatype) ? INT8_MIN : 0) \
595 )
596 
597 #define	TAINT_WARN	0
598 #define	test_taint(x)	(0)
599 
600 /*
601  * Checking if an option is defined would be easy if we could do CPP inside CPP.
602  * The defined case whether -Dxxx or -Dxxx=1 are easy to deal with.  In either
603  * case the defined value is "1". A more general -Dxxx=<c> case will require
604  * more effort to deal with all possible "true" values. Hope we do not have
605  * to do this as well.
606  * The real problem is the undefined case.  To avoid this problem we do the
607  * concat/varargs trick: "yyy" ## xxx can make two arguments if xxx is "1"
608  * by having a #define for yyy_1 which is "ignore,".
609  * Otherwise we will just get "yyy".
610  * Need to be careful about variable substitutions in macros though.
611  * This way we make a (true, false) problem a (don't care, true, false) or a
612  * (don't care true, false).  Then we can use a variadic macro to only select
613  * the always well known and defined argument #2.  And that seems to be
614  * exactly what we need.  Use 1 for true and 0 for false to also allow
615  * #if IS_*() checks pre-compiler checks which do not like #if true.
616  */
617 #define ___XAB_1		dontcare,
618 #define ___IS_XAB(_ignore, _x, ...)	(_x)
619 #define	__IS_XAB(_x)		___IS_XAB(_x 1, 0)
620 #define	_IS_XAB(_x)		__IS_XAB(__CONCAT(___XAB_, _x))
621 
622 /* This is if CONFIG_ccc=y. */
623 #define	IS_BUILTIN(_x)		_IS_XAB(_x)
624 /* This is if CONFIG_ccc=m. */
625 #define	IS_MODULE(_x)		_IS_XAB(_x ## _MODULE)
626 /* This is if CONFIG_ccc is compiled in(=y) or a module(=m). */
627 #define	IS_ENABLED(_x)		(IS_BUILTIN(_x) || IS_MODULE(_x))
628 /*
629  * This is weird case.  If the CONFIG_ccc is builtin (=y) this returns true;
630  * or if the CONFIG_ccc is a module (=m) and the caller is built as a module
631  * (-DMODULE defined) this returns true, but if the callers is not a module
632  * (-DMODULE not defined, which means caller is BUILTIN) then it returns
633  * false.  In other words, a module can reach the kernel, a module can reach
634  * a module, but the kernel cannot reach a module, and code never compiled
635  * cannot be reached either.
636  * XXX -- I'd hope the module-to-module case would be handled by a proper
637  * module dependency definition (MODULE_DEPEND() in FreeBSD).
638  */
639 #define	IS_REACHABLE(_x)	(IS_BUILTIN(_x) || \
640 				    (IS_MODULE(_x) && IS_BUILTIN(MODULE)))
641 
642 #endif	/* _LINUX_KERNEL_H_ */
643