blob: eadac22a48ffd63e407c6db2c7b01ed57c33d407 [file] [log] [blame]
/* Copyright 2011 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/*
* Shared memory interface for Chrome EC.
*
* This is intended to supply a relatively large block of memory for use by a
* task for a relatively short amount of time. For example, verified boot may
* need a buffer to hold signature data during a verification operation. It is
* NOT intended for allocating long-term buffers; those should in general be
* static variables allocated at compile-time. It is NOT a full-featured
* replacement for malloc() / free().
*/
#ifndef __CROS_EC_SHARED_MEM_H
#define __CROS_EC_SHARED_MEM_H
#include "common.h"
#include <stddef.h>
/**
* Returns the maximum amount of shared memory which can be acquired, in
* bytes.
*/
int shared_mem_size(void);
#define SHARED_MEM_CHECK_SIZE(size) \
BUILD_ASSERT((size) <= CONFIG_SHAREDMEM_MINIMUM_SIZE)
/*
* Acquires a shared memory area of the requested size in bytes.
*
* Doing a sysjump between images will corrupt and/or erase shared memory as
* jump tags are added and .bss is reinitialized. Due to the way jump tags are
* added to the end of RAM, shared memory must not be allocated, accessed, or
* freed after the start of a sysjump (for example, in HOOK_SYSJUMP).
*
* @param size Number of bytes requested
* @param dest_ptr If successful, set on return to the start of the
* granted memory buffer.
*
* @return EC_SUCCESS if successful, EC_ERROR_BUSY if buffer in use, or
* other non-zero error code.
*/
int shared_mem_acquire(int size, char **dest_ptr);
#define SHARED_MEM_ACQUIRE_CHECK(size, dest_ptr) \
({ \
SHARED_MEM_CHECK_SIZE(size); \
shared_mem_acquire((size), (dest_ptr)); \
})
/**
* Releases a shared memory area previously allocated via shared_mem_acquire().
*/
void shared_mem_release(void *ptr);
/*
* This structure is allocated at the base of the free memory chunk and every
* allocated buffer.
*/
struct shm_buffer {
struct shm_buffer *next_buffer;
struct shm_buffer *prev_buffer;
size_t buffer_size;
};
#ifdef TEST_SHMALLOC
/*
* When in test mode, all possible paths in the allocation/free functions set
* unique bits in an integer bitmap.
*
* The test function generates random allocation and free requests and
* monitors the bitmap until all bits have been set, which indicates that all
* possible paths have been executed.
*/
#define MAX_MASK_BIT 24
#define ALL_PATHS_MASK ((1 << (MAX_MASK_BIT + 1)) - 1)
void set_map_bit(uint32_t mask);
extern struct shm_buffer *free_buf_chain;
extern struct shm_buffer *allocced_buf_chain;
#endif
#endif /* __CROS_EC_SHARED_MEM_H */