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kernel.h revision 1.8 
      1 /*	$NetBSD: kernel.h,v 1.8 2015/08/20 21:41:12 skrll Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     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/param.h>
     38 #include <sys/systm.h>
     39 
     40 #include <lib/libkern/libkern.h>
     41 
     42 #define	oops_in_progress	(panicstr != NULL)
     43 
     44 #define	IS_ENABLED(option)	(option)
     45 
     46 #define	__printf	__printflike
     47 #define	__user
     48 #define	__must_check	/* __attribute__((warn_unused_result)), if GCC */
     49 #define	__always_unused	__unused
     50 
     51 #define	barrier()	__insn_barrier()
     52 #define	likely(X)	__predict_true(X)
     53 #define	unlikely(X)	__predict_false(X)
     54 
     55 /*
     56  * XXX Linux kludge to work around GCC uninitialized variable warning.
     57  * Linux does `x = x', which is bollocks.
     58  */
     59 #define	uninitialized_var(x)	x = 0
     60 
     61 /* XXX These will multiply evaluate their arguments.  */
     62 #define	max_t(T, X, Y)	MAX(X, Y)
     63 #define	min_t(T, X, Y)	MIN(X, Y)
     64 
     65 #define	clamp_t(T, X, MIN, MAX)	min_t(T, max_t(T, X, MIN), MAX)
     66 #define	clamp(X, MN, MX)	MIN(MAX(X, MN), MX)
     67 
     68 /*
     69  * Rounding to nearest.
     70  */
     71 #define	DIV_ROUND_CLOSEST(N, D)						\
     72 	((0 < (N)) ? (((N) + ((D) / 2)) / (D))				\
     73 	    : (((N) - ((D) / 2)) / (D)))
     74 
     75 /*
     76  * Rounding to what may or may not be powers of two.
     77  */
     78 #define	DIV_ROUND_UP(X, N)	(((X) + (N) - 1) / (N))
     79 #define	DIV_ROUND_UP_ULL(X, N)	DIV_ROUND_UP((unsigned long long)(X), (N))
     80 
     81 /*
     82  * Rounding to powers of two -- carefully avoiding multiple evaluation
     83  * of arguments and pitfalls with C integer arithmetic rules.
     84  */
     85 #define	round_up(X, N)		((((X) - 1) | ((N) - 1)) + 1)
     86 #define	round_down(X, N)	((X) & ~(uintmax_t)((N) - 1))
     87 
     88 #define	IS_ALIGNED(X, N)	(((X) & ((N) - 1)) == 0)
     89 
     90 /*
     91  * These select 32-bit halves of what may be 32- or 64-bit quantities,
     92  * for which straight 32-bit shifts may be undefined behaviour (and do
     93  * the wrong thing on most machines: return the input unshifted by
     94  * ignoring the upper bits of the shift count).
     95  */
     96 #define	upper_32_bits(X)	((uint32_t) (((X) >> 16) >> 16))
     97 #define	lower_32_bits(X)	((uint32_t) ((X) & 0xffffffffUL))
     98 
     99 #define	ARRAY_SIZE(ARRAY)	__arraycount(ARRAY)
    100 
    101 #define	swap(X, Y)	do						\
    102 {									\
    103 	/* XXX Kludge for type-safety.  */				\
    104 	if (&(X) != &(Y)) {						\
    105 		CTASSERT(sizeof(X) == sizeof(Y));			\
    106 		/* XXX Can't do this much better without typeof.  */	\
    107 		char __swap_tmp[sizeof(X)];				\
    108 		(void)memcpy(__swap_tmp, &(X), sizeof(X));		\
    109 		(void)memcpy(&(X), &(Y), sizeof(X));			\
    110 		(void)memcpy(&(Y), __swap_tmp, sizeof(X));		\
    111 	}								\
    112 } while (0)
    113 
    114 static inline int64_t
    115 abs64(int64_t x)
    116 {
    117 	return (x < 0? (-x) : x);
    118 }
    119 
    120 static inline uintmax_t
    121 mult_frac(uintmax_t x, uintmax_t multiplier, uintmax_t divisor)
    122 {
    123 	uintmax_t q = (x / divisor);
    124 	uintmax_t r = (x % divisor);
    125 
    126 	return ((q * multiplier) + ((r * multiplier) / divisor));
    127 }
    128 
    129 static int panic_timeout __unused = 0;
    130 
    131 static inline int
    132 vscnprintf(char *buf, size_t size, const char *fmt, va_list va)
    133 {
    134 	int ret;
    135 
    136 	ret = vsnprintf(buf, size, fmt, va);
    137 	if (__predict_false(ret < 0))
    138 		return ret;
    139 	if (__predict_false(size == 0))
    140 		return 0;
    141 	if (__predict_false(size <= ret))
    142 		return (size - 1);
    143 
    144 	return ret;
    145 }
    146 
    147 static inline int
    148 scnprintf(char *buf, size_t size, const char *fmt, ...)
    149 {
    150 	va_list va;
    151 	int ret;
    152 
    153 	va_start(va, fmt);
    154 	ret = vscnprintf(buf, size, fmt, va);
    155 	va_end(va);
    156 
    157 	return ret;
    158 }
    159 
    160 static inline int
    161 kstrtol(const char *s, unsigned base, long *vp)
    162 {
    163 	long long v;
    164 
    165 	v = strtoll(s, NULL, base);
    166 	if (v < LONG_MIN || LONG_MAX < v)
    167 		return -ERANGE;
    168 	*vp = v;
    169 	return 0;
    170 }
    171 
    172 #endif  /* _LINUX_KERNEL_H_ */
    173