path: root/include/linux/kernel.h

#ifndef _LINUX_KERNEL_H
#define _LINUX_KERNEL_H


#include <stdarg.h>
#include <linux/linkage.h>
#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/compiler.h>
#include <linux/bitops.h>
#include <linux/log2.h>
#include <linux/typecheck.h>
#include <linux/printk.h>
#include <linux/dynamic_debug.h>
#include <asm/byteorder.h>
#include <uapi/linux/kernel.h>

#define USHRT_MAX	((u16)(~0U))
#define SHRT_MAX	((s16)(USHRT_MAX>>1))
#define SHRT_MIN	((s16)(-SHRT_MAX - 1))
#define INT_MAX		((int)(~0U>>1))
#define INT_MIN		(-INT_MAX - 1)
#define UINT_MAX	(~0U)
#define LONG_MAX	((long)(~0UL>>1))
#define LONG_MIN	(-LONG_MAX - 1)
#define ULONG_MAX	(~0UL)
#define LLONG_MAX	((long long)(~0ULL>>1))
#define LLONG_MIN	(-LLONG_MAX - 1)
#define ULLONG_MAX	(~0ULL)
#define SIZE_MAX	(~(size_t)0)

#define U8_MAX		((u8)~0U)
#define S8_MAX		((s8)(U8_MAX>>1))
#define S8_MIN		((s8)(-S8_MAX - 1))
#define U16_MAX		((u16)~0U)
#define S16_MAX		((s16)(U16_MAX>>1))
#define S16_MIN		((s16)(-S16_MAX - 1))
#define U32_MAX		((u32)~0U)
#define S32_MAX		((s32)(U32_MAX>>1))
#define S32_MIN		((s32)(-S32_MAX - 1))
#define U64_MAX		((u64)~0ULL)
#define S64_MAX		((s64)(U64_MAX>>1))
#define S64_MIN		((s64)(-S64_MAX - 1))

#define STACK_MAGIC	0xdeadbeef

#define REPEAT_BYTE(x)	((~0ul / 0xff) * (x))

#define ALIGN(x, a)		__ALIGN_KERNEL((x), (a))
#define __ALIGN_MASK(x, mask)	__ALIGN_KERNEL_MASK((x), (mask))
#define PTR_ALIGN(p, a)		((typeof(p))ALIGN((unsigned long)(p), (a)))
#define IS_ALIGNED(x, a)		(((x) & ((typeof(x))(a) - 1)) == 0)

#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))

/*
 * This looks more complex than it should be. But we need to
 * get the type for the ~ right in round_down (it needs to be
 * as wide as the result!), and we want to evaluate the macro
 * arguments just once each.
 */
#define __round_mask(x, y) ((__typeof__(x))((y)-1))
#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
#define round_down(x, y) ((x) & ~__round_mask(x, y))

#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
#define DIV_ROUND_UP_ULL(ll,d) \
	({ unsigned long long _tmp = (ll)+(d)-1; do_div(_tmp, d); _tmp; })

#if BITS_PER_LONG == 32
# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d)
#else
# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d)
#endif

/* The `const' in roundup() prevents gcc-3.3 from calling __divdi3 */
#define roundup(x, y) (					\
{							\
	const typeof(y) __y = y;			\
	(((x) + (__y - 1)) / __y) * __y;		\
}							\
)
#define rounddown(x, y) (				\
{							\
	typeof(x) __x = (x);				\
	__x - (__x % (y));				\
}							\
)

/*
 * Divide positive or negative dividend by positive divisor and round
 * to closest integer. Result is undefined for negative divisors and
 * for negative dividends if the divisor variable type is unsigned.
 */
#define DIV_ROUND_CLOSEST(x, divisor)(			\
{							\
	typeof(x) __x = x;				\
	typeof(divisor) __d = divisor;			\
	(((typeof(x))-1) > 0 ||				\
	 ((typeof(divisor))-1) > 0 || (__x) > 0) ?	\
		(((__x) + ((__d) / 2)) / (__d)) :	\
		(((__x) - ((__d) / 2)) / (__d));	\
}							\
)
/*
 * Same as above but for u64 dividends. divisor must be a 32-bit
 * number.
 */
#define DIV_ROUND_CLOSEST_ULL(x, divisor)(		\
{							\
	typeof(divisor) __d = divisor;			\
	unsigned long long _tmp = (x) + (__d) / 2;	\
	do_div(_tmp, __d);				\
	_tmp;						\
}							\
)

/*
 * Multiplies an integer by a fraction, while avoiding unnecessary
 * overflow or loss of precision.
 */
#define mult_frac(x, numer, denom)(			\
{							\
	typeof(x) quot = (x) / (denom);			\
	typeof(x) rem  = (x) % (denom);			\
	(quot * (numer)) + ((rem * (numer)) / (denom));	\
}							\
)


#define _RET_IP_		(unsigned long)__builtin_return_address(0)
#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })

#ifdef CONFIG_LBDAF
# include <asm/div64.h>
# define sector_div(a, b) do_div(a, b)
#else
# define sector_div(n, b)( \
{ \
	int _res; \
	_res = (n) % (b); \
	(n) /= (b); \
	_res; \
} \
)
#endif

/**
 * upper_32_bits - return bits 32-63 of a number
 * @n: the number we're accessing
 *
 * A basic shift-right of a 64- or 32-bit quantity.  Use this to suppress
 * the "right shift count >= width of type" warning when that quantity is
 * 32-bits.
 */
#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16))

/**
 * lower_32_bits - return bits 0-31 of a number
 * @n: the number we're accessing
 */
#define lower_32_bits(n) ((u32)(n))

struct completion;
struct pt_regs;
struct user;

#ifdef CONFIG_PREEMPT_VOLUNTARY
extern int _cond_resched(void);
# define might_resched() _cond_resched()
#else
# define might_resched() do { } while (0)
#endif

#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
  void ___might_sleep(const char *file, int line, int preempt_offset);
  void __might_sleep(const char *file, int line, int preempt_offset);
/**
 * might_sleep - annotation for functions that can sleep
 *
 * this macro will print a stack trace if it is executed in an atomic
 * context (spinlock, irq-handler, ...).
 *
 * This is a useful debugging help to be able to catch problems early and not
 * be bitten later when the calling function happens to sleep when it is not
 * supposed to.
 */
# define might_sleep() \
	do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
# define sched_annotate_sleep()	(current->task_state_change = 0)
#else
  static inline void ___might_sleep(const char *file, int line,
				   int preempt_offset) { }
  static inline void __might_sleep(const char *file, int line,
				   int preempt_offset) { }
# define might_sleep() do { might_resched(); } while (0)
# define sched_annotate_sleep() do { } while (0)
#endif

#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)

/**
 * abs - return absolute value of an argument
 * @x: the value.  If it is unsigned type, it is converted to signed type first.
 *     char is treated as if it was signed (regardless of whether it really is)
 *     but the macro's return type is preserved as char.
 *
 * Return: an absolute value of x.
 */
#define abs(x)	__abs_choose_expr(x, long long,				\
		__abs_choose_expr(x, long,				\
		__abs_choose_expr(x, int,				\
		__abs_choose_expr(x, short,				\
		__abs_choose_expr(x, char,				\
		__builtin_choose_expr(					\
			__builtin_types_compatible_p(typeof(x), char),	\
			(char)({ signed char __x = (x); __x<0?-__x:__x; }), \
			((void)0)))))))

#define __abs_choose_expr(x, type, other) __builtin_choose_expr(	\
	__builtin_types_compatible_p(typeof(x),   signed type) ||	\
	__builtin_types_compatible_p(typeof(x), unsigned type),		\
	({ signed type __x = (x); __x < 0 ? -__x : __x; }), other)

/**
 * reciprocal_scale - "scale" a value into range [0, ep_ro)
 * @val: value
 * @ep_ro: right open interval endpoint
 *
 * Perform a "reciprocal multiplication" in order to "scale" a value into
 * range [0, ep_ro), where the upper interval endpoint is right-open.
 * This is useful, e.g. for accessing a index of an array containing
 * ep_ro elements, for example. Think of it as sort of modulus, only that
 * the result isn't that of modulo. ;) Note that if initial input is a
 * small value, then result will return 0.
 *
 * Return: a result based on val in interval [0, ep_ro).
 */
static inline u32 reciprocal_scale(u32 val, u32 ep_ro)
{
	return (u32)(((u64) val * ep_ro) >> 32);
}

#if defined(CONFIG_MMU) && \
	(defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP))
#define might_fault() __might_fault(__FILE__, __LINE__)
void __might_fault(const char *file, int line);
#else
static inline void might_fault(void) { }
#endif

extern struct atomic_notifier_head panic_notifier_list;
extern long (*panic_blink)(int state);
__printf(1, 2)
void panic(const char *fmt, ...)
	__noreturn __cold;
void nmi_panic(struct pt_regs *regs, const char *msg);
extern void oops_enter(void);
extern void oops_exit(void);
void print_oops_end_marker(void);
extern int oops_may_print(void);
void do_exit(long error_code)
	__noreturn;
void complete_and_exit(struct completion *, long)
	__noreturn;

/* Internal, do not use. */
int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
int __must_check _kstrtol(const char *s, unsigned int base, long *res);

int __must_check kstrtoull(const char *s, unsigned int base, unsigned long long *res);
int __must_check kstrtoll(const char *s, unsigned int base, long long *res);

/**
 * kstrtoul - convert a string to an unsigned long
 * @s: The start of the string. The string must be null-terminated, and may also
 *  include a single newline before its terminating null. The first character
 *  may also be a plus sign, but not a minus sign.
 * @base: The number base to use. The maximum supported base is 16. If base is
 *  given as 0, then the base of the string is automatically detected with the
 *  conventional semantics - If it begins with 0x the number will be parsed as a
 *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
 *  parsed as an octal number. Otherwise it will be parsed as a decimal.
 * @res: Where to write the result of the conversion on success.
 *
 * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
 * Used as a replacement for the obsolete simple_strtoull. Return code must
 * be checked.
*/
static inline int __must_check kstrtoul(const char *s, unsigned int base, unsigned long *res)
{
	/*
	 * We want to shortcut function call, but
	 * __builtin_types_compatible_p(unsigned long, unsigned long long) = 0.
	 */
	if (sizeof(unsigned long) == sizeof(unsigned long long) &&
	    __alignof__(unsigned long) == __alignof__(unsigned long long))
		return kstrtoull(s, base, (unsigned long long *)res);
	else
		return