coreboot: add memory pool infrastructure

The memory pool infrastructure provides an allocator with
very simple free()ing semantics: only the most recent allocation
can be freed from the pool. However, it can be reset and when
not used any longer providing the entire region for future
allocations.

Change-Id: I5ae9ab35bb769d78bbc2866c5ae3b5ce2cdce5fa
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9129
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
Aaron Durbin 2015-03-26 12:29:12 -05:00
parent 5d5f4b3c84
commit 127525c772
3 changed files with 129 additions and 0 deletions

73
src/include/mem_pool.h Normal file
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@ -0,0 +1,73 @@
/*
* This file is part of the coreboot project.
*
* Copyright 2015 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* 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.
*/
#ifndef _MEM_POOL_H_
#define _MEM_POOL_H_
#include <stddef.h>
#include <stdint.h>
/*
* The memory pool allows one to allocate memory from a fixed size buffer
* that also allows freeing semantics for reuse. However, the current
* limitation is that the most recent allocation is the only one that
* can be freed. If one tries to free any allocation that isn't the
* most recently allocated it will result in a leak within the memory pool.
*
* The memory returned by allocations are at least 8 byte aligned. Note
* that this requires the backing buffer to start on at least an 8 byte
* alignment.
*/
struct mem_pool {
uint8_t *buf;
size_t size;
uint8_t *last_alloc;
size_t free_offset;
};
#define MEM_POOL_INIT(buf_, size_) \
{ \
.buf = (buf_), \
.size = (size_), \
.last_alloc = NULL, \
.free_offset = 0, \
}
static inline void mem_pool_reset(struct mem_pool *mp)
{
mp->last_alloc = NULL;
mp->free_offset = 0;
}
/* Initialize a memory pool. */
static inline void mem_pool_init(struct mem_pool *mp, void *buf, size_t sz)
{
mp->buf = buf;
mp->size = sz;
mem_pool_reset(mp);
}
/* Allocate requested size from the memory pool. NULL returned on error. */
void *mem_pool_alloc(struct mem_pool *mp, size_t sz);
/* Free allocation from memory pool. */
void mem_pool_free(struct mem_pool *mp, void *alloc);
#endif /* _MEM_POOL_H_ */

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@ -29,6 +29,7 @@ bootblock-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
bootblock-$(CONFIG_CONSOLE_CBMEM) += cbmem_console.c
bootblock-y += memchr.c
bootblock-y += memcmp.c
bootblock-y += mem_pool.c
bootblock-y += region.c
verstage-y += prog_ops.c
@ -50,6 +51,7 @@ endif
verstage-$(CONFIG_GENERIC_UDELAY) += timer.c
verstage-$(CONFIG_GENERIC_GPIO_LIB) += gpio.c
verstage-y += mem_pool.c
romstage-y += prog_ops.c
romstage-y += memchr.c
@ -134,6 +136,9 @@ ramstage-$(CONFIG_RELOCATABLE_RAMSTAGE) += cbmem_stage_cache.c
romstage-$(CONFIG_RELOCATABLE_RAMSTAGE) += cbmem_stage_cache.c
endif
romstage-y += mem_pool.c
ramstage-y += mem_pool.c
romstage-y += region.c
ramstage-y += region.c

51
src/lib/mem_pool.c Normal file
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@ -0,0 +1,51 @@
/*
* This file is part of the coreboot project.
*
* Copyright 2015 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* 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.
*/
#include <mem_pool.h>
#include <stdlib.h>
void *mem_pool_alloc(struct mem_pool *mp, size_t sz)
{
void *p;
/* Make all allocations be at least 8 byte aligned. */
sz = ALIGN_UP(sz, 8);
/* Determine if any space available. */
if ((mp->size - mp->free_offset) < sz)
return NULL;
p = &mp->buf[mp->free_offset];
mp->free_offset += sz;
mp->last_alloc = p;
return p;
}
void mem_pool_free(struct mem_pool *mp, void *p)
{
/* Determine if p was the most recent allocation. */
if (p == NULL || mp->last_alloc != p)
return;
mp->free_offset = mp->last_alloc - mp->buf;
/* No way to track allocation before this one. */
mp->last_alloc = NULL;
}