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94 lines
2.8 KiB
94 lines
2.8 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* User memory access support for Hexagon |
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* |
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* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. |
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*/ |
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#ifndef _ASM_UACCESS_H |
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#define _ASM_UACCESS_H |
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/* |
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* User space memory access functions |
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*/ |
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#include <asm/sections.h> |
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/* |
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* access_ok: - Checks if a user space pointer is valid |
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* @addr: User space pointer to start of block to check |
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* @size: Size of block to check |
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* |
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* Context: User context only. This function may sleep if pagefaults are |
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* enabled. |
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* |
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* Checks if a pointer to a block of memory in user space is valid. |
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* |
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* Returns true (nonzero) if the memory block *may* be valid, false (zero) |
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* if it is definitely invalid. |
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* |
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* User address space in Hexagon, like x86, goes to 0xbfffffff, so the |
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* simple MSB-based tests used by MIPS won't work. Some further |
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* optimization is probably possible here, but for now, keep it |
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* reasonably simple and not *too* slow. After all, we've got the |
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* MMU for backup. |
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*/ |
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#define __access_ok(addr, size) \ |
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((get_fs().seg == KERNEL_DS.seg) || \ |
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(((unsigned long)addr < get_fs().seg) && \ |
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(unsigned long)size < (get_fs().seg - (unsigned long)addr))) |
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/* |
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* When a kernel-mode page fault is taken, the faulting instruction |
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* address is checked against a table of exception_table_entries. |
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* Each entry is a tuple of the address of an instruction that may |
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* be authorized to fault, and the address at which execution should |
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* be resumed instead of the faulting instruction, so as to effect |
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* a workaround. |
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*/ |
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/* Assembly somewhat optimized copy routines */ |
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unsigned long raw_copy_from_user(void *to, const void __user *from, |
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unsigned long n); |
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unsigned long raw_copy_to_user(void __user *to, const void *from, |
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unsigned long n); |
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#define INLINE_COPY_FROM_USER |
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#define INLINE_COPY_TO_USER |
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__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count); |
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#define __clear_user(a, s) __clear_user_hexagon((a), (s)) |
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#define __strncpy_from_user(dst, src, n) hexagon_strncpy_from_user(dst, src, n) |
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/* get around the ifndef in asm-generic/uaccess.h */ |
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#define __strnlen_user __strnlen_user |
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extern long __strnlen_user(const char __user *src, long n); |
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static inline long hexagon_strncpy_from_user(char *dst, const char __user *src, |
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long n); |
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#include <asm-generic/uaccess.h> |
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/* Todo: an actual accelerated version of this. */ |
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static inline long hexagon_strncpy_from_user(char *dst, const char __user *src, |
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long n) |
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{ |
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long res = __strnlen_user(src, n); |
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if (unlikely(!res)) |
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return -EFAULT; |
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if (res > n) { |
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long left = raw_copy_from_user(dst, src, n); |
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if (unlikely(left)) |
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memset(dst + (n - left), 0, left); |
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return n; |
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} else { |
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long left = raw_copy_from_user(dst, src, res); |
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if (unlikely(left)) |
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memset(dst + (res - left), 0, left); |
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return res-1; |
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} |
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} |
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#endif
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