| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* |
| * User memory access support for Hexagon |
| * |
| * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. |
| */ |
| |
| #ifndef _ASM_UACCESS_H |
| #define _ASM_UACCESS_H |
| /* |
| * User space memory access functions |
| */ |
| #include <linux/mm.h> |
| #include <asm/sections.h> |
| |
| /* |
| * access_ok: - Checks if a user space pointer is valid |
| * @addr: User space pointer to start of block to check |
| * @size: Size of block to check |
| * |
| * Context: User context only. This function may sleep if pagefaults are |
| * enabled. |
| * |
| * 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 __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 raw_copy_from_user(void *to, const void __user *from, |
| unsigned long n); |
| unsigned long raw_copy_to_user(void __user *to, const void *from, |
| unsigned long n); |
| #define INLINE_COPY_FROM_USER |
| #define INLINE_COPY_TO_USER |
| |
| __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); |
| |
| if (unlikely(!res)) |
| return -EFAULT; |
| |
| if (res > n) { |
| long left = raw_copy_from_user(dst, src, n); |
| if (unlikely(left)) |
| memset(dst + (n - left), 0, left); |
| return n; |
| } else { |
| long left = raw_copy_from_user(dst, src, res); |
| if (unlikely(left)) |
| memset(dst + (res - left), 0, left); |
| return res-1; |
| } |
| } |
| |
| #endif |