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Diffstat (limited to 'arch/hexagon/include/asm/uaccess.h')
| -rw-r--r-- | arch/hexagon/include/asm/uaccess.h | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/arch/hexagon/include/asm/uaccess.h b/arch/hexagon/include/asm/uaccess.h new file mode 100644 index 00000000000..7e706eadbf0 --- /dev/null +++ b/arch/hexagon/include/asm/uaccess.h @@ -0,0 +1,116 @@ +/* + * User memory access support for Hexagon + * + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#ifndef _ASM_UACCESS_H +#define _ASM_UACCESS_H +/* + * User space memory access functions + */ +#include <linux/sched.h> +#include <linux/mm.h> +#include <asm/segment.h> +#include <asm/sections.h> + +/* + * access_ok: - Checks if a user space pointer is valid + * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that + * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe + * to write to a block, it is always safe to read from it. + * @addr: User space pointer to start of block to check + * @size: Size of block to check + * + * Context: User context only. This function may sleep. + * + * Checks if a pointer to a block of memory in user space is valid. + * + * Returns true (nonzero) if the memory block *may* be valid, false (zero) + * if it is definitely invalid. + * + * User address space in Hexagon, like x86, goes to 0xbfffffff, so the + * simple MSB-based tests used by MIPS won't work. Some further + * optimization is probably possible here, but for now, keep it + * reasonably simple and not *too* slow. After all, we've got the + * MMU for backup. + */ +#define VERIFY_READ 0 +#define VERIFY_WRITE 1 + +#define __access_ok(addr, size) \ + ((get_fs().seg == KERNEL_DS.seg) || \ + (((unsigned long)addr < get_fs().seg) && \ + (unsigned long)size < (get_fs().seg - (unsigned long)addr))) + +/* + * When a kernel-mode page fault is taken, the faulting instruction + * address is checked against a table of exception_table_entries. + * Each entry is a tuple of the address of an instruction that may + * be authorized to fault, and the address at which execution should + * be resumed instead of the faulting instruction, so as to effect + * a workaround. + */ + +/* Assembly somewhat optimized copy routines */ +unsigned long __copy_from_user_hexagon(void *to, const void __user *from, + unsigned long n); +unsigned long __copy_to_user_hexagon(void __user *to, const void *from, + unsigned long n); + +#define __copy_from_user(to, from, n) __copy_from_user_hexagon(to, from, n) +#define __copy_to_user(to, from, n) __copy_to_user_hexagon(to, from, n) + +/* + * XXX todo: some additonal performance gain is possible by + * implementing __copy_to/from_user_inatomic, which is much + * like __copy_to/from_user, but performs slightly less checking. + */ + +__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count); +#define __clear_user(a, s) __clear_user_hexagon((a), (s)) + +#define __strncpy_from_user(dst, src, n) hexagon_strncpy_from_user(dst, src, n) + +/* get around the ifndef in asm-generic/uaccess.h */ +#define __strnlen_user __strnlen_user + +extern long __strnlen_user(const char __user *src, long n); + +static inline long hexagon_strncpy_from_user(char *dst, const char __user *src, + long n); + +#include <asm-generic/uaccess.h> + +/* Todo: an actual accelerated version of this. */ +static inline long hexagon_strncpy_from_user(char *dst, const char __user *src, + long n) +{ + long res = __strnlen_user(src, n); + + /* return from strnlen can't be zero -- that would be rubbish. */ + + if (res > n) { + copy_from_user(dst, src, n); + return n; + } else { + copy_from_user(dst, src, res); + return res-1; + } +} + +#endif |