path: root/include/linux/kernel.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_KERNEL_H
#define _LINUX_KERNEL_H

#include <stdarg.h>
#include <linux/limits.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/math.h>
#include <linux/minmax.h>
#include <linux/typecheck.h>
#include <linux/printk.h>
#include <linux/build_bug.h>

#include <asm/byteorder.h>

#include <uapi/linux/kernel.h>

#define STACK_MAGIC	0xdeadbeef

/**
 * REPEAT_BYTE - repeat the value @x multiple times as an unsigned long value
 * @x: value to repeat
 *
 * NOTE: @x is not checked for > 0xff; larger values produce odd results.
 */
#define REPEAT_BYTE(x)	((~0ul / 0xff) * (x))

/* @a is a power of 2 value */
#define ALIGN(x, a)		__ALIGN_KERNEL((x), (a))
#define ALIGN_DOWN(x, a)	__ALIGN_KERNEL((x) - ((a) - 1), (a))
#define __ALIGN_MASK(x, mask)	__ALIGN_KERNEL_MASK((x), (mask))
#define PTR_ALIGN(p, a)		((typeof(p))ALIGN((unsigned long)(p), (a)))
#define PTR_ALIGN_DOWN(p, a)	((typeof(p))ALIGN_DOWN((unsigned long)(p), (a)))
#define IS_ALIGNED(x, a)		(((x) & ((typeof(x))(a) - 1)) == 0)

/* generic data direction definitions */
#define READ			0
#define WRITE			1

/**
 * ARRAY_SIZE - get the number of elements in array @arr
 * @arr: array to be sized
 */
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))

#define u64_to_user_ptr(x) (		\
{					\
	typecheck(u64, (x));		\
	(void __user *)(uintptr_t)(x);	\
}					\
)

#define typeof_member(T, m)	typeof(((T*)0)->m)

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

/**
 * 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) & 0xffffffff))

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
extern void ___might_sleep(const char *file, int line, int preempt_offset);
extern void __might_sleep(const char *file, int line, int preempt_offset);
extern void __cant_sleep(const char *file, int line, int preempt_offset);
extern void __cant_migrate(const char *file, int line);

/**
 * 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, ...). Additional sections where blocking is
 * not allowed can be annotated with non_block_start() and non_block_end()
 * pairs.
 *
 * 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)
/**
 * cant_sleep - annotation for functions that cannot sleep
 *
 * this macro will print a stack trace if it is executed with preemption enabled
 */
# define cant_sleep() \
	do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
# define sched_annotate_sleep()	(current->task_state_change = 0)

/**
 * cant_migrate - annotation for functions that cannot migrate
 *
 * Will print a stack trace if executed in code which is migratable
 */
# define cant_migrate()							\
	do {								\
		if (IS_ENABLED(CONFIG_SMP))				\
			__cant_migrate(__FILE__, __LINE__);		\
	} while (0)

/**
 * non_block_start - annotate the start of section where sleeping is prohibited
 *
 * This is on behalf of the oom reaper, specifically when it is calling the mmu
 * notifiers. The problem is that if the notifier were to block on, for example,
 * mutex_lock() and if the process which holds that mutex were to perform a
 * sleeping memory allocation, the oom reaper is now blocked on completion of
 * that memory allocation. Other blocking calls like wait_event() pose similar
 * issues.
 */
# define non_block_start() (current->non_block_count++)
/**
 * non_block_end - annotate the end of section where sleeping is prohibited
 *
 * Closes a section opened by non_block_start().
 */
# define non_block_end() WARN_ON(current->non_block_count-- == 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 cant_sleep() do { } while (0)
# define cant_migrate()		do { } while (0)
# define sched_annotate_sleep() do { } while (0)
# define non_block_start() do { } while (0)
# define non_block_end() do { } while (0)
#endif

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

#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);
extern bool 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.
 * Preferred over simple_strtoul(). 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 _kstrtoul(s, base, res);
}

/**
 * kstrtol - convert a string to a 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 or 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.
 * Preferred over simple_strtol(). Return code must be checked.
 */
static inline int __must_check kstrtol(const char *s, unsigned int base, long *res)
{
	/*
	 * We want to shortcut function call, but
	 * __builtin_types_compatible_p(long, long long) = 0.
	 */
	if (sizeof(long) == sizeof(long long) &&
	    __alignof__(long) == __alignof__(long long))
		return kstrtoll(s, base, (long long *)res);
	else
		return _kstrtol(s, base, res);
}

int __must_check kstrtouint(const char *s, unsigned int base, unsigned int *res);
int __must_check kstrtoint(const char *s, unsigned int base, int *res);

static inline int __must_check kstrtou64(const char *s, unsigned int base, u64 *res)
{
	return kstrtoull(s, base, res);
}

static inline int __must_check kstrtos64(const char *s, unsigned int base, s64 *res)
{
	return kstrtoll(s, base,