[mirror_ubuntu-artful-kernel.git] / tools / include / linux / err.h

#ifndef __TOOLS_LINUX_ERR_H
#define __TOOLS_LINUX_ERR_H

#include <linux/compiler.h>
#include <linux/types.h>

#include <asm/errno.h>

/*
 * Original kernel header comment:
 *
 * Kernel pointers have redundant information, so we can use a
 * scheme where we can return either an error code or a normal
 * pointer with the same return value.
 *
 * This should be a per-architecture thing, to allow different
 * error and pointer decisions.
 *
 * Userspace note:
 * The same principle works for userspace, because 'error' pointers
 * fall down to the unused hole far from user space, as described
 * in Documentation/x86/x86_64/mm.txt for x86_64 arch:
 *
 * 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
 * ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
 *
 * It should be the same case for other architectures, because
 * this code is used in generic kernel code.
 */
#define MAX_ERRNO	4095

#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)

static inline void * __must_check ERR_PTR(long error_)
{
	return (void *) error_;
}

static inline long __must_check PTR_ERR(__force const void *ptr)
{
	return (long) ptr;
}

static inline bool __must_check IS_ERR(__force const void *ptr)
{
	return IS_ERR_VALUE((unsigned long)ptr);
}

static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
{
	return unlikely(!ptr) || IS_ERR_VALUE((unsigned long)ptr);
}

#endif /* _LINUX_ERR_H */
Commit	Line	Data
01ca9fd4 JO	1	#ifndef __TOOLS_LINUX_ERR_H
	2	#define __TOOLS_LINUX_ERR_H
	3
	4	#include <linux/compiler.h>
	5	#include <linux/types.h>
	6
	7	#include <asm/errno.h>
	8
	9	/*
	10	* Original kernel header comment:
	11	*
	12	* Kernel pointers have redundant information, so we can use a
	13	* scheme where we can return either an error code or a normal
	14	* pointer with the same return value.
	15	*
	16	* This should be a per-architecture thing, to allow different
	17	* error and pointer decisions.
	18	*
	19	* Userspace note:
	20	* The same principle works for userspace, because 'error' pointers
	21	* fall down to the unused hole far from user space, as described
	22	* in Documentation/x86/x86_64/mm.txt for x86_64 arch:
	23	*
	24	* 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension
	25	* ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
	26	*
	27	* It should be the same case for other architectures, because
	28	* this code is used in generic kernel code.
	29	*/
	30	#define MAX_ERRNO 4095
	31
	32	#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
	33
45633a16	34	static inline void * __must_check ERR_PTR(long error_)
01ca9fd4	35	{
45633a16	36	return (void *) error_;
01ca9fd4 JO	37	}
	38
	39	static inline long __must_check PTR_ERR(__force const void *ptr)
	40	{
	41	return (long) ptr;
	42	}
	43
	44	static inline bool __must_check IS_ERR(__force const void *ptr)
	45	{
	46	return IS_ERR_VALUE((unsigned long)ptr);
	47	}
	48
61d4595e LASL	49	static inline bool __must_check IS_ERR_OR_NULL(__force const void *ptr)
	50	{
	51	return unlikely(!ptr) \|\| IS_ERR_VALUE((unsigned long)ptr);
	52	}
	53
01ca9fd4	54	#endif /* _LINUX_ERR_H */