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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_GENERIC_ACCESS_OK_H__
#define __ASM_GENERIC_ACCESS_OK_H__
/*
* Checking whether a pointer is valid for user space access.
* These definitions work on most architectures, but overrides can
* be used where necessary.
*/
/*
* architectures with compat tasks have a variable TASK_SIZE and should
* override this to a constant.
*/
#ifndef TASK_SIZE_MAX
#define TASK_SIZE_MAX TASK_SIZE
#endif
#ifndef __access_ok
/*
* 'size' is a compile-time constant for most callers, so optimize for
* this case to turn the check into a single comparison against a constant
* limit and catch all possible overflows.
* On architectures with separate user address space (m68k, s390, parisc,
* sparc64) or those without an MMU, this should always return true.
*
* This version was originally contributed by Jonas Bonn for the
* OpenRISC architecture, and was found to be the most efficient
* for constant 'size' and 'limit' values.
*/
static inline int __access_ok(const void __user *ptr, unsigned long size)
{
unsigned long limit = TASK_SIZE_MAX;
unsigned long addr = (unsigned long)ptr;
if (IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE) ||
!IS_ENABLED(CONFIG_MMU))
return true;
return (size <= limit) && (addr <= (limit - size));
}
#endif
#ifndef access_ok
#define access_ok(addr, size) likely(__access_ok(addr, size))
#endif
#endif
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