xref: /freebsd/sys/compat/linuxkpi/common/include/linux/kernel.h (revision 2d5d2a986ce1a93b8567dbdf3f80bc2b545d6998)
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	_LINUXKPI_LINUX_KERNEL_H_
33 #define	_LINUXKPI_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/stringify.h>
49 #include <linux/errno.h>
50 #include <linux/sched.h>
51 #include <linux/types.h>
52 #include <linux/jiffies.h>
53 #include <linux/log2.h>
54 
55 #include <asm/byteorder.h>
56 #include <asm/uaccess.h>
57 
58 #include <machine/stdarg.h>
59 
60 #define KERN_CONT       ""
61 #define	KERN_EMERG	"<0>"
62 #define	KERN_ALERT	"<1>"
63 #define	KERN_CRIT	"<2>"
64 #define	KERN_ERR	"<3>"
65 #define	KERN_WARNING	"<4>"
66 #define	KERN_NOTICE	"<5>"
67 #define	KERN_INFO	"<6>"
68 #define	KERN_DEBUG	"<7>"
69 
70 #define	U8_MAX		((u8)~0U)
71 #define	S8_MAX		((s8)(U8_MAX >> 1))
72 #define	S8_MIN		((s8)(-S8_MAX - 1))
73 #define	U16_MAX		((u16)~0U)
74 #define	S16_MAX		((s16)(U16_MAX >> 1))
75 #define	S16_MIN		((s16)(-S16_MAX - 1))
76 #define	U32_MAX		((u32)~0U)
77 #define	S32_MAX		((s32)(U32_MAX >> 1))
78 #define	S32_MIN		((s32)(-S32_MAX - 1))
79 #define	U64_MAX		((u64)~0ULL)
80 #define	S64_MAX		((s64)(U64_MAX >> 1))
81 #define	S64_MIN		((s64)(-S64_MAX - 1))
82 
83 #define	S8_C(x)  x
84 #define	U8_C(x)  x ## U
85 #define	S16_C(x) x
86 #define	U16_C(x) x ## U
87 #define	S32_C(x) x
88 #define	U32_C(x) x ## U
89 #define	S64_C(x) x ## LL
90 #define	U64_C(x) x ## ULL
91 
92 /*
93  * BUILD_BUG_ON() can happen inside functions where _Static_assert() does not
94  * seem to work.  Use old-schoold-ish CTASSERT from before commit
95  * a3085588a88fa58eb5b1eaae471999e1995a29cf but also make sure we do not
96  * end up with an unused typedef or variable. The compiler should optimise
97  * it away entirely.
98  */
99 #define	_O_CTASSERT(x)		_O__CTASSERT(x, __LINE__)
100 #define	_O__CTASSERT(x, y)	_O___CTASSERT(x, y)
101 #define	_O___CTASSERT(x, y)	while (0) { \
102     typedef char __assert_line_ ## y[(x) ? 1 : -1]; \
103     __assert_line_ ## y _x; \
104     _x[0] = '\0'; \
105 }
106 
107 #define	BUILD_BUG()			do { CTASSERT(0); } while (0)
108 #define	BUILD_BUG_ON(x)			do { _O_CTASSERT(!(x)) } while (0)
109 #define	BUILD_BUG_ON_MSG(x, msg)	BUILD_BUG_ON(x)
110 #define	BUILD_BUG_ON_NOT_POWER_OF_2(x)	BUILD_BUG_ON(!powerof2(x))
111 #define	BUILD_BUG_ON_INVALID(expr)	while (0) { (void)(expr); }
112 #define	BUILD_BUG_ON_ZERO(x)	((int)sizeof(struct { int:-((x) != 0); }))
113 
114 #define	BUG()			panic("BUG at %s:%d", __FILE__, __LINE__)
115 #define	BUG_ON(cond)		do {				\
116 	if (cond) {						\
117 		panic("BUG ON %s failed at %s:%d",		\
118 		    __stringify(cond), __FILE__, __LINE__);	\
119 	}							\
120 } while (0)
121 
122 extern int linuxkpi_warn_dump_stack;
123 #define	WARN_ON(cond) ({					\
124 	bool __ret = (cond);					\
125 	if (__ret) {						\
126 		printf("WARNING %s failed at %s:%d\n",		\
127 		    __stringify(cond), __FILE__, __LINE__);	\
128 		if (linuxkpi_warn_dump_stack)				\
129 			linux_dump_stack();				\
130 	}								\
131 	unlikely(__ret);						\
132 })
133 
134 #define	WARN_ON_SMP(cond)	WARN_ON(cond)
135 
136 #define	WARN_ON_ONCE(cond) ({					\
137 	static bool __warn_on_once;				\
138 	bool __ret = (cond);					\
139 	if (__ret && !__warn_on_once) {				\
140 		__warn_on_once = 1;				\
141 		printf("WARNING %s failed at %s:%d\n",		\
142 		    __stringify(cond), __FILE__, __LINE__);	\
143 		if (linuxkpi_warn_dump_stack)				\
144 			linux_dump_stack();				\
145 	}								\
146 	unlikely(__ret);						\
147 })
148 
149 #define	oops_in_progress	SCHEDULER_STOPPED()
150 
151 #undef	ALIGN
152 #define	ALIGN(x, y)		roundup2((x), (y))
153 #undef PTR_ALIGN
154 #define	PTR_ALIGN(p, a)		((__typeof(p))ALIGN((uintptr_t)(p), (a)))
155 #define	IS_ALIGNED(x, a)	(((x) & ((__typeof(x))(a) - 1)) == 0)
156 #define	DIV_ROUND_UP(x, n)	howmany(x, n)
157 #define	__KERNEL_DIV_ROUND_UP(x, n)	howmany(x, n)
158 #define	DIV_ROUND_UP_ULL(x, n)	DIV_ROUND_UP((unsigned long long)(x), (n))
159 #define	DIV_ROUND_DOWN_ULL(x, n) (((unsigned long long)(x) / (n)) * (n))
160 #define	FIELD_SIZEOF(t, f)	sizeof(((t *)0)->f)
161 
162 #define	printk(...)		printf(__VA_ARGS__)
163 #define	vprintk(f, a)		vprintf(f, a)
164 
165 #define	asm			__asm
166 
167 extern void linux_dump_stack(void);
168 #define	dump_stack()		linux_dump_stack()
169 
170 struct va_format {
171 	const char *fmt;
172 	va_list *va;
173 };
174 
175 static inline int
176 vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
177 {
178 	ssize_t ssize = size;
179 	int i;
180 
181 	i = vsnprintf(buf, size, fmt, args);
182 
183 	return ((i >= ssize) ? (ssize - 1) : i);
184 }
185 
186 static inline int
187 scnprintf(char *buf, size_t size, const char *fmt, ...)
188 {
189 	va_list args;
190 	int i;
191 
192 	va_start(args, fmt);
193 	i = vscnprintf(buf, size, fmt, args);
194 	va_end(args);
195 
196 	return (i);
197 }
198 
199 /*
200  * The "pr_debug()" and "pr_devel()" macros should produce zero code
201  * unless DEBUG is defined:
202  */
203 #ifdef DEBUG
204 extern int linuxkpi_debug;
205 #define pr_debug(fmt, ...)					\
206 	do {							\
207 		if (linuxkpi_debug)				\
208 			log(LOG_DEBUG, fmt, ##__VA_ARGS__);	\
209 	} while (0)
210 #define pr_devel(fmt, ...) \
211 	log(LOG_DEBUG, pr_fmt(fmt), ##__VA_ARGS__)
212 #else
213 #define pr_debug(fmt, ...) \
214 	({ if (0) log(LOG_DEBUG, fmt, ##__VA_ARGS__); 0; })
215 #define pr_devel(fmt, ...) \
216 	({ if (0) log(LOG_DEBUG, pr_fmt(fmt), ##__VA_ARGS__); 0; })
217 #endif
218 
219 #ifndef pr_fmt
220 #define pr_fmt(fmt) fmt
221 #endif
222 
223 /*
224  * Print a one-time message (analogous to WARN_ONCE() et al):
225  */
226 #define printk_once(...) do {			\
227 	static bool __print_once;		\
228 						\
229 	if (!__print_once) {			\
230 		__print_once = true;		\
231 		printk(__VA_ARGS__);		\
232 	}					\
233 } while (0)
234 
235 /*
236  * Log a one-time message (analogous to WARN_ONCE() et al):
237  */
238 #define log_once(level,...) do {		\
239 	static bool __log_once;			\
240 						\
241 	if (unlikely(!__log_once)) {		\
242 		__log_once = true;		\
243 		log(level, __VA_ARGS__);	\
244 	}					\
245 } while (0)
246 
247 #define pr_emerg(fmt, ...) \
248 	log(LOG_EMERG, pr_fmt(fmt), ##__VA_ARGS__)
249 #define pr_alert(fmt, ...) \
250 	log(LOG_ALERT, pr_fmt(fmt), ##__VA_ARGS__)
251 #define pr_crit(fmt, ...) \
252 	log(LOG_CRIT, pr_fmt(fmt), ##__VA_ARGS__)
253 #define pr_err(fmt, ...) \
254 	log(LOG_ERR, pr_fmt(fmt), ##__VA_ARGS__)
255 #define pr_err_once(fmt, ...) \
256 	log_once(LOG_ERR, pr_fmt(fmt), ##__VA_ARGS__)
257 #define pr_warning(fmt, ...) \
258 	log(LOG_WARNING, pr_fmt(fmt), ##__VA_ARGS__)
259 #define pr_warn(...) \
260 	pr_warning(__VA_ARGS__)
261 #define pr_warn_once(fmt, ...) \
262 	log_once(LOG_WARNING, pr_fmt(fmt), ##__VA_ARGS__)
263 #define pr_notice(fmt, ...) \
264 	log(LOG_NOTICE, pr_fmt(fmt), ##__VA_ARGS__)
265 #define pr_info(fmt, ...) \
266 	log(LOG_INFO, pr_fmt(fmt), ##__VA_ARGS__)
267 #define pr_info_once(fmt, ...) \
268 	log_once(LOG_INFO, pr_fmt(fmt), ##__VA_ARGS__)
269 #define pr_cont(fmt, ...) \
270 	printk(KERN_CONT fmt, ##__VA_ARGS__)
271 #define	pr_warn_ratelimited(...) do {		\
272 	static linux_ratelimit_t __ratelimited;	\
273 	if (linux_ratelimited(&__ratelimited))	\
274 		pr_warning(__VA_ARGS__);	\
275 } while (0)
276 
277 #ifndef WARN
278 #define	WARN(condition, ...) ({			\
279 	bool __ret_warn_on = (condition);	\
280 	if (unlikely(__ret_warn_on))		\
281 		pr_warning(__VA_ARGS__);	\
282 	unlikely(__ret_warn_on);		\
283 })
284 #endif
285 
286 #ifndef WARN_ONCE
287 #define	WARN_ONCE(condition, ...) ({		\
288 	bool __ret_warn_on = (condition);	\
289 	if (unlikely(__ret_warn_on))		\
290 		pr_warn_once(__VA_ARGS__);	\
291 	unlikely(__ret_warn_on);		\
292 })
293 #endif
294 
295 #define container_of(ptr, type, member)				\
296 ({								\
297 	const __typeof(((type *)0)->member) *__p = (ptr);	\
298 	(type *)((uintptr_t)__p - offsetof(type, member));	\
299 })
300 
301 #define	ARRAY_SIZE(x)	(sizeof(x) / sizeof((x)[0]))
302 
303 #define	u64_to_user_ptr(val)	((void *)(uintptr_t)(val))
304 
305 #define _RET_IP_		__builtin_return_address(0)
306 
307 static inline unsigned long long
308 simple_strtoull(const char *cp, char **endp, unsigned int base)
309 {
310 	return (strtouq(cp, endp, base));
311 }
312 
313 static inline long long
314 simple_strtoll(const char *cp, char **endp, unsigned int base)
315 {
316 	return (strtoq(cp, endp, base));
317 }
318 
319 static inline unsigned long
320 simple_strtoul(const char *cp, char **endp, unsigned int base)
321 {
322 	return (strtoul(cp, endp, base));
323 }
324 
325 static inline long
326 simple_strtol(const char *cp, char **endp, unsigned int base)
327 {
328 	return (strtol(cp, endp, base));
329 }
330 
331 static inline int
332 kstrtoul(const char *cp, unsigned int base, unsigned long *res)
333 {
334 	char *end;
335 
336 	*res = strtoul(cp, &end, base);
337 
338 	/* skip newline character, if any */
339 	if (*end == '\n')
340 		end++;
341 	if (*cp == 0 || *end != 0)
342 		return (-EINVAL);
343 	return (0);
344 }
345 
346 static inline int
347 kstrtol(const char *cp, unsigned int base, long *res)
348 {
349 	char *end;
350 
351 	*res = strtol(cp, &end, base);
352 
353 	/* skip newline character, if any */
354 	if (*end == '\n')
355 		end++;
356 	if (*cp == 0 || *end != 0)
357 		return (-EINVAL);
358 	return (0);
359 }
360 
361 static inline int
362 kstrtoint(const char *cp, unsigned int base, int *res)
363 {
364 	char *end;
365 	long temp;
366 
367 	*res = temp = strtol(cp, &end, base);
368 
369 	/* skip newline character, if any */
370 	if (*end == '\n')
371 		end++;
372 	if (*cp == 0 || *end != 0)
373 		return (-EINVAL);
374 	if (temp != (int)temp)
375 		return (-ERANGE);
376 	return (0);
377 }
378 
379 static inline int
380 kstrtouint(const char *cp, unsigned int base, unsigned int *res)
381 {
382 	char *end;
383 	unsigned long temp;
384 
385 	*res = temp = strtoul(cp, &end, base);
386 
387 	/* skip newline character, if any */
388 	if (*end == '\n')
389 		end++;
390 	if (*cp == 0 || *end != 0)
391 		return (-EINVAL);
392 	if (temp != (unsigned int)temp)
393 		return (-ERANGE);
394 	return (0);
395 }
396 
397 static inline int
398 kstrtou8(const char *cp, unsigned int base, u8 *res)
399 {
400 	char *end;
401 	unsigned long temp;
402 
403 	*res = temp = strtoul(cp, &end, base);
404 
405 	/* skip newline character, if any */
406 	if (*end == '\n')
407 		end++;
408 	if (*cp == 0 || *end != 0)
409 		return (-EINVAL);
410 	if (temp != (u8)temp)
411 		return (-ERANGE);
412 	return (0);
413 }
414 
415 static inline int
416 kstrtou16(const char *cp, unsigned int base, u16 *res)
417 {
418 	char *end;
419 	unsigned long temp;
420 
421 	*res = temp = strtoul(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 	if (temp != (u16)temp)
429 		return (-ERANGE);
430 	return (0);
431 }
432 
433 static inline int
434 kstrtou32(const char *cp, unsigned int base, u32 *res)
435 {
436 	char *end;
437 	unsigned long temp;
438 
439 	*res = temp = strtoul(cp, &end, base);
440 
441 	/* skip newline character, if any */
442 	if (*end == '\n')
443 		end++;
444 	if (*cp == 0 || *end != 0)
445 		return (-EINVAL);
446 	if (temp != (u32)temp)
447 		return (-ERANGE);
448 	return (0);
449 }
450 
451 static inline int
452 kstrtou64(const char *cp, unsigned int base, u64 *res)
453 {
454        char *end;
455 
456        *res = strtouq(cp, &end, base);
457 
458        /* skip newline character, if any */
459        if (*end == '\n')
460                end++;
461        if (*cp == 0 || *end != 0)
462                return (-EINVAL);
463        return (0);
464 }
465 
466 static inline int
467 kstrtoull(const char *cp, unsigned int base, unsigned long long *res)
468 {
469 	return (kstrtou64(cp, base, (u64 *)res));
470 }
471 
472 static inline int
473 kstrtobool(const char *s, bool *res)
474 {
475 	int len;
476 
477 	if (s == NULL || (len = strlen(s)) == 0 || res == NULL)
478 		return (-EINVAL);
479 
480 	/* skip newline character, if any */
481 	if (s[len - 1] == '\n')
482 		len--;
483 
484 	if (len == 1 && strchr("yY1", s[0]) != NULL)
485 		*res = true;
486 	else if (len == 1 && strchr("nN0", s[0]) != NULL)
487 		*res = false;
488 	else if (strncasecmp("on", s, len) == 0)
489 		*res = true;
490 	else if (strncasecmp("off", s, len) == 0)
491 		*res = false;
492 	else
493 		return (-EINVAL);
494 
495 	return (0);
496 }
497 
498 static inline int
499 kstrtobool_from_user(const char __user *s, size_t count, bool *res)
500 {
501 	char buf[8] = {};
502 
503 	if (count > (sizeof(buf) - 1))
504 		count = (sizeof(buf) - 1);
505 
506 	if (copy_from_user(buf, s, count))
507 		return (-EFAULT);
508 
509 	return (kstrtobool(buf, res));
510 }
511 
512 static inline int
513 kstrtoint_from_user(const char __user *s, size_t count, unsigned int base,
514     int *p)
515 {
516 	char buf[36] = {};
517 
518 	if (count > (sizeof(buf) - 1))
519 		count = (sizeof(buf) - 1);
520 
521 	if (copy_from_user(buf, s, count))
522 		return (-EFAULT);
523 
524 	return (kstrtoint(buf, base, p));
525 }
526 
527 static inline int
528 kstrtou8_from_user(const char __user *s, size_t count, unsigned int base,
529     u8 *p)
530 {
531 	char buf[8] = {};
532 
533 	if (count > (sizeof(buf) - 1))
534 		count = (sizeof(buf) - 1);
535 
536 	if (copy_from_user(buf, s, count))
537 		return (-EFAULT);
538 
539 	return (kstrtou8(buf, base, p));
540 }
541 
542 #define min(x, y)	((x) < (y) ? (x) : (y))
543 #define max(x, y)	((x) > (y) ? (x) : (y))
544 
545 #define min3(a, b, c)	min(a, min(b,c))
546 #define max3(a, b, c)	max(a, max(b,c))
547 
548 #define	min_t(type, x, y) ({			\
549 	type __min1 = (x);			\
550 	type __min2 = (y);			\
551 	__min1 < __min2 ? __min1 : __min2; })
552 
553 #define	max_t(type, x, y) ({			\
554 	type __max1 = (x);			\
555 	type __max2 = (y);			\
556 	__max1 > __max2 ? __max1 : __max2; })
557 
558 #define offsetofend(t, m)	\
559         (offsetof(t, m) + sizeof((((t *)0)->m)))
560 
561 #define clamp_t(type, _x, min, max)	min_t(type, max_t(type, _x, min), max)
562 #define clamp(x, lo, hi)		min( max(x,lo), hi)
563 #define	clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
564 
565 /*
566  * This looks more complex than it should be. But we need to
567  * get the type for the ~ right in round_down (it needs to be
568  * as wide as the result!), and we want to evaluate the macro
569  * arguments just once each.
570  */
571 #define __round_mask(x, y) ((__typeof__(x))((y)-1))
572 #define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
573 #define round_down(x, y) ((x) & ~__round_mask(x, y))
574 
575 #define	smp_processor_id()	PCPU_GET(cpuid)
576 #define	num_possible_cpus()	mp_ncpus
577 #define	num_online_cpus()	mp_ncpus
578 
579 #if defined(__i386__) || defined(__amd64__)
580 extern bool linux_cpu_has_clflush;
581 #define	cpu_has_clflush		linux_cpu_has_clflush
582 #endif
583 
584 typedef struct pm_message {
585 	int event;
586 } pm_message_t;
587 
588 /* Swap values of a and b */
589 #define swap(a, b) do {			\
590 	typeof(a) _swap_tmp = a;	\
591 	a = b;				\
592 	b = _swap_tmp;			\
593 } while (0)
594 
595 #define	DIV_ROUND_CLOSEST(x, divisor)	(((x) + ((divisor) / 2)) / (divisor))
596 
597 #define	DIV_ROUND_CLOSEST_ULL(x, divisor) ({		\
598 	__typeof(divisor) __d = (divisor);		\
599 	unsigned long long __ret = (x) + (__d) / 2;	\
600 	__ret /= __d;					\
601 	__ret;						\
602 })
603 
604 static inline uintmax_t
605 mult_frac(uintmax_t x, uintmax_t multiplier, uintmax_t divisor)
606 {
607 	uintmax_t q = (x / divisor);
608 	uintmax_t r = (x % divisor);
609 
610 	return ((q * multiplier) + ((r * multiplier) / divisor));
611 }
612 
613 static inline int64_t
614 abs64(int64_t x)
615 {
616 	return (x < 0 ? -x : x);
617 }
618 
619 typedef struct linux_ratelimit {
620 	struct timeval lasttime;
621 	int counter;
622 } linux_ratelimit_t;
623 
624 static inline bool
625 linux_ratelimited(linux_ratelimit_t *rl)
626 {
627 	return (ppsratecheck(&rl->lasttime, &rl->counter, 1));
628 }
629 
630 #define	struct_size(ptr, field, num) ({ \
631 	const size_t __size = offsetof(__typeof(*(ptr)), field); \
632 	const size_t __max = (SIZE_MAX - __size) / sizeof((ptr)->field[0]); \
633 	((num) > __max) ? SIZE_MAX : (__size + sizeof((ptr)->field[0]) * (num)); \
634 })
635 
636 #define	__is_constexpr(x) \
637 	__builtin_constant_p(x)
638 
639 /*
640  * The is_signed() macro below returns true if the passed data type is
641  * signed. Else false is returned.
642  */
643 #define	is_signed(datatype) (((datatype)-1 / (datatype)2) == (datatype)0)
644 
645 /*
646  * The type_max() macro below returns the maxium positive value the
647  * passed data type can hold.
648  */
649 #define	type_max(datatype) ( \
650   (sizeof(datatype) >= 8) ? (is_signed(datatype) ? INT64_MAX : UINT64_MAX) : \
651   (sizeof(datatype) >= 4) ? (is_signed(datatype) ? INT32_MAX : UINT32_MAX) : \
652   (sizeof(datatype) >= 2) ? (is_signed(datatype) ? INT16_MAX : UINT16_MAX) : \
653 			    (is_signed(datatype) ? INT8_MAX : UINT8_MAX) \
654 )
655 
656 /*
657  * The type_min() macro below returns the minimum value the passed
658  * data type can hold. For unsigned types the minimum value is always
659  * zero. For signed types it may vary.
660  */
661 #define	type_min(datatype) ( \
662   (sizeof(datatype) >= 8) ? (is_signed(datatype) ? INT64_MIN : 0) : \
663   (sizeof(datatype) >= 4) ? (is_signed(datatype) ? INT32_MIN : 0) : \
664   (sizeof(datatype) >= 2) ? (is_signed(datatype) ? INT16_MIN : 0) : \
665 			    (is_signed(datatype) ? INT8_MIN : 0) \
666 )
667 
668 #define	TAINT_WARN	0
669 #define	test_taint(x)	(0)
670 
671 static inline int
672 _h2b(const char c)
673 {
674 
675 	if (c >= '0' && c <= '9')
676 		return (c - '0');
677 	if (c >= 'a' && c <= 'f')
678 		return (10 + c - 'a');
679 	if (c >= 'A' && c <= 'F')
680 		return (10 + c - 'A');
681 	return (-EINVAL);
682 }
683 
684 static inline int
685 hex2bin(uint8_t *bindst, const char *hexsrc, size_t binlen)
686 {
687 	int hi4, lo4;
688 
689 	while (binlen > 0) {
690 		hi4 = _h2b(*hexsrc++);
691 		lo4 = _h2b(*hexsrc++);
692 		if (hi4 < 0 || lo4 < 0)
693 			return (-EINVAL);
694 
695 		*bindst++ = (hi4 << 4) | lo4;
696 		binlen--;
697 	}
698 
699 	return (0);
700 }
701 
702 #define	DECLARE_FLEX_ARRAY(_t, _n)					\
703     struct { struct { } __dummy_ ## _n; _t _n[0]; }
704 
705 /*
706  * Checking if an option is defined would be easy if we could do CPP inside CPP.
707  * The defined case whether -Dxxx or -Dxxx=1 are easy to deal with.  In either
708  * case the defined value is "1". A more general -Dxxx=<c> case will require
709  * more effort to deal with all possible "true" values. Hope we do not have
710  * to do this as well.
711  * The real problem is the undefined case.  To avoid this problem we do the
712  * concat/varargs trick: "yyy" ## xxx can make two arguments if xxx is "1"
713  * by having a #define for yyy_1 which is "ignore,".
714  * Otherwise we will just get "yyy".
715  * Need to be careful about variable substitutions in macros though.
716  * This way we make a (true, false) problem a (don't care, true, false) or a
717  * (don't care true, false).  Then we can use a variadic macro to only select
718  * the always well known and defined argument #2.  And that seems to be
719  * exactly what we need.  Use 1 for true and 0 for false to also allow
720  * #if IS_*() checks pre-compiler checks which do not like #if true.
721  */
722 #define ___XAB_1		dontcare,
723 #define ___IS_XAB(_ignore, _x, ...)	(_x)
724 #define	__IS_XAB(_x)		___IS_XAB(_x 1, 0)
725 #define	_IS_XAB(_x)		__IS_XAB(__CONCAT(___XAB_, _x))
726 
727 /* This is if CONFIG_ccc=y. */
728 #define	IS_BUILTIN(_x)		_IS_XAB(_x)
729 /* This is if CONFIG_ccc=m. */
730 #define	IS_MODULE(_x)		_IS_XAB(_x ## _MODULE)
731 /* This is if CONFIG_ccc is compiled in(=y) or a module(=m). */
732 #define	IS_ENABLED(_x)		(IS_BUILTIN(_x) || IS_MODULE(_x))
733 /*
734  * This is weird case.  If the CONFIG_ccc is builtin (=y) this returns true;
735  * or if the CONFIG_ccc is a module (=m) and the caller is built as a module
736  * (-DMODULE defined) this returns true, but if the callers is not a module
737  * (-DMODULE not defined, which means caller is BUILTIN) then it returns
738  * false.  In other words, a module can reach the kernel, a module can reach
739  * a module, but the kernel cannot reach a module, and code never compiled
740  * cannot be reached either.
741  * XXX -- I'd hope the module-to-module case would be handled by a proper
742  * module dependency definition (MODULE_DEPEND() in FreeBSD).
743  */
744 #define	IS_REACHABLE(_x)	(IS_BUILTIN(_x) || \
745 				    (IS_MODULE(_x) && IS_BUILTIN(MODULE)))
746 
747 #endif	/* _LINUXKPI_LINUX_KERNEL_H_ */
748