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>
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@ -0,0 +1,73 @@
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/*
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* This file is part of the coreboot project.
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*
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* Copyright 2015 Google Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc.
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*/
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#ifndef _MEM_POOL_H_
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#define _MEM_POOL_H_
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#include <stddef.h>
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#include <stdint.h>
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/*
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* The memory pool allows one to allocate memory from a fixed size buffer
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* that also allows freeing semantics for reuse. However, the current
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* limitation is that the most recent allocation is the only one that
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* can be freed. If one tries to free any allocation that isn't the
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* most recently allocated it will result in a leak within the memory pool.
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*
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* The memory returned by allocations are at least 8 byte aligned. Note
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* that this requires the backing buffer to start on at least an 8 byte
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* alignment.
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*/
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struct mem_pool {
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uint8_t *buf;
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size_t size;
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uint8_t *last_alloc;
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size_t free_offset;
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};
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#define MEM_POOL_INIT(buf_, size_) \
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{ \
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.buf = (buf_), \
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.size = (size_), \
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.last_alloc = NULL, \
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.free_offset = 0, \
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}
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static inline void mem_pool_reset(struct mem_pool *mp)
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{
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mp->last_alloc = NULL;
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mp->free_offset = 0;
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}
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/* Initialize a memory pool. */
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static inline void mem_pool_init(struct mem_pool *mp, void *buf, size_t sz)
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{
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mp->buf = buf;
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mp->size = sz;
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mem_pool_reset(mp);
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}
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/* Allocate requested size from the memory pool. NULL returned on error. */
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void *mem_pool_alloc(struct mem_pool *mp, size_t sz);
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/* Free allocation from memory pool. */
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void mem_pool_free(struct mem_pool *mp, void *alloc);
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#endif /* _MEM_POOL_H_ */
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@ -29,6 +29,7 @@ bootblock-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
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bootblock-$(CONFIG_CONSOLE_CBMEM) += cbmem_console.c
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bootblock-y += memchr.c
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bootblock-y += memcmp.c
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bootblock-y += mem_pool.c
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bootblock-y += region.c
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verstage-y += prog_ops.c
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@ -50,6 +51,7 @@ endif
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verstage-$(CONFIG_GENERIC_UDELAY) += timer.c
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verstage-$(CONFIG_GENERIC_GPIO_LIB) += gpio.c
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verstage-y += mem_pool.c
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romstage-y += prog_ops.c
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romstage-y += memchr.c
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@ -134,6 +136,9 @@ ramstage-$(CONFIG_RELOCATABLE_RAMSTAGE) += cbmem_stage_cache.c
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romstage-$(CONFIG_RELOCATABLE_RAMSTAGE) += cbmem_stage_cache.c
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endif
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romstage-y += mem_pool.c
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ramstage-y += mem_pool.c
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romstage-y += region.c
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ramstage-y += region.c
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@ -0,0 +1,51 @@
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/*
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* This file is part of the coreboot project.
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*
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* Copyright 2015 Google Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc.
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*/
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#include <mem_pool.h>
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#include <stdlib.h>
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void *mem_pool_alloc(struct mem_pool *mp, size_t sz)
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{
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void *p;
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/* Make all allocations be at least 8 byte aligned. */
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sz = ALIGN_UP(sz, 8);
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/* Determine if any space available. */
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if ((mp->size - mp->free_offset) < sz)
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return NULL;
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p = &mp->buf[mp->free_offset];
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mp->free_offset += sz;
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mp->last_alloc = p;
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return p;
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}
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void mem_pool_free(struct mem_pool *mp, void *p)
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{
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/* Determine if p was the most recent allocation. */
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if (p == NULL || mp->last_alloc != p)
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return;
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mp->free_offset = mp->last_alloc - mp->buf;
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/* No way to track allocation before this one. */
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mp->last_alloc = NULL;
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}
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