155 lines
4.9 KiB
C
155 lines
4.9 KiB
C
/*
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* Copyright (c) 2015 Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#ifndef _debug__mem_safe__h_
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#define _debug__mem_safe__h_
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#include <errno.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @file
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* @brief Safe memory access routines
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*
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* This module provides functions for safely writing to and reading from
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* memory, as well as probing if a memory address is accessible. For the
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* latter, permissions can be specified (read/write).
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*/
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#define SYS_MEM_SAFE_READ 0
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#define SYS_MEM_SAFE_WRITE 1
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/**
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* @brief verify memory at an address is accessible
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*
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* Probe memory for read or write access by specifying the @a perm, either
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* SYS_MEM_SAFE_WRITE or SYS_MEM_SAFE_READ. A size @a num_bytes specifying
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* the number of bytes to access must also be specified: for a 32-bit system,
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* it can only take the values 1,2 or 4 (8/16/32 bits). Both @a p and @a buf
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* must be naturally aligned to @a num_bytes.
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*
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* On a read, the value read from the memory location @a p is returned through
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* @a buf; on a write, the value contained in @a buf is written to memory at
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* memory location @a p.
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*
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* @param p The pointer (address) to the location to probe
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* @param perm Either SYS_MEM_PROBE_READ or SYS_MEM_PROBE_WRITE
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* @param num_bytes The number of bytes to probe, must be either 1, 2 or 4
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* @param buf On reads, will contain the value read; on writes, contains the
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* value to write
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*
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* @retval 0 OK
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* @retval -EINVAL If an invalid parameter is passed
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* @retval -EFAULT If the address is not accessible.
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*/
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extern int _mem_probe(void *p, int perm, size_t num_bytes, void *buf);
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/**
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* @brief safely read memory
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*
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* @details Read @a num_bytes bytes at address @a src from buffer pointed to
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* by @a buf. The @a width parameter specifies bus width of each memory access
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* in bytes. If @a width is 0 a target optimal access width is used. All other
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* values of access width are target dependent and optional. When @a width is
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* non-zero, the both @a num_bytes and @a src must be a multiple of @a width.
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*
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* @param src The address to read from
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* @param buf The destination buffer to receive the data read
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* @param num_bytes The number of bytes to read
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* @param width The access width
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*
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* @retval 0 OK
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* @retval -EFAULT If there was an error reading memory
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* @retval -EINVAL If access width, num_bytes and addresses are not compatible.
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*/
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extern int _mem_safe_read(void *src, char *buf, size_t num_bytes,
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int width);
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/**
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* @brief safely write memory
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*
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* @details Write @a num_bytes bytes to address @a dest from buffer pointed to
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* by @a buf. The @a width parameter specifies bus width of each memory access
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* in bytes. If @a width is 0 a target optimal access width is used. All other
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* values of access width are target dependent and optional. When @a width is
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* non-zero, the both @a num_bytes and @a dest must be a multiple of @a width.
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*
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* @param dest The address to write to
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* @param buf The source buffer to write in memory
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* @param num_bytes The number of bytes to write
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* @param width The access width
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*
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* @retval 0 OK
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* @retval -EFAULT If there was an error writing memory
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* @retval -EINVAL If access width, num_bytes and addresses are not compatible.
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*/
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extern int _mem_safe_write(void *dest, char *buf, size_t num_bytes,
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int width);
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/**
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* @brief write to text section
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*
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* @details Write @a num_bytes bytes to address @a dest from buffer pointed to
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* by @a buf.
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*
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* @param dest The address to write to
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* @param buf The source buffer to write in memory
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* @param num_bytes The number of bytes to write
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*
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* @retval 0 Success
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* @retval -EFAULT If there was an error writing memory
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*/
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extern int _mem_safe_write_to_text_section(void *dest, char *buf,
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size_t num_bytes);
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/**
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* @brief add to the table of valid regions
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*
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* @details Add a new region that is considered valid to read from or both
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* read from and write to. The region starts at @a addr and its size is @a
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* num_bytes. The read/write permissions are specified via @a perm and can
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* take the values either SYS_MEM_SAFE_READ or SYS_MEM_SAFE_WRITE.
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*
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* The table size is specified via the CONFIG_MEM_SAFE_NUM_EXTRA_REGIONS kconfig
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* option.
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*
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* If the implementation of safe memory access chosen does not need this API,
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* it is still available, but results in a no-op and always returns success
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* (0).
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*
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* @param addr The address to write to
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* @param num_bytes The size of the region in bytes
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* @param perm The access permissions, either SYS_MEM_SAFE_WRITE or
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* SYS_MEM_SAFE_READ
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*
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* @retval 0 OK
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* @retval -ENOMEM If there there is no space left in the table of regions
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* @retval -EINVAL If passing invalid permissions
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*/
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#ifdef CONFIG_MEM_SAFE_CHECK_BOUNDARIES
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extern int _mem_safe_region_add(void *addr, size_t num_bytes, int perm);
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#else
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static inline int _mem_safe_region_add(void *addr, size_t num_bytes,
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int perm)
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{
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return 0;
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}
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* _debug__mem_safe__h_ */
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