linux/sound/core/memalloc.c
Takashi Iwai 5c1733e33c ALSA: memalloc: Align buffer allocations in page size
Currently the standard memory allocator (snd_dma_malloc_pages*())
passes the byte size to allocate as is.  Most of the backends
allocates real pages, hence the actual allocations are aligned in page
size.  However, the genalloc doesn't seem assuring the size alignment,
hence it may result in the access outside the buffer when the whole
memory pages are exposed via mmap.

For avoiding such inconsistencies, this patch makes the allocation
size always to be aligned in page size.

Note that, after this change, snd_dma_buffer.bytes field contains the
aligned size, not the originally requested size.  This value is also
used for releasing the pages in return.

Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20201218145625.2045-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-12-18 17:09:10 +01:00

258 lines
6.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
* Takashi Iwai <tiwai@suse.de>
*
* Generic memory allocators
*/
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/genalloc.h>
#include <linux/vmalloc.h>
#ifdef CONFIG_X86
#include <asm/set_memory.h>
#endif
#include <sound/memalloc.h>
/*
*
* Bus-specific memory allocators
*
*/
#ifdef CONFIG_HAS_DMA
/* allocate the coherent DMA pages */
static void snd_malloc_dev_pages(struct snd_dma_buffer *dmab, size_t size)
{
gfp_t gfp_flags;
gfp_flags = GFP_KERNEL
| __GFP_COMP /* compound page lets parts be mapped */
| __GFP_NORETRY /* don't trigger OOM-killer */
| __GFP_NOWARN; /* no stack trace print - this call is non-critical */
dmab->area = dma_alloc_coherent(dmab->dev.dev, size, &dmab->addr,
gfp_flags);
#ifdef CONFIG_X86
if (dmab->area && dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC)
set_memory_wc((unsigned long)dmab->area,
PAGE_ALIGN(size) >> PAGE_SHIFT);
#endif
}
/* free the coherent DMA pages */
static void snd_free_dev_pages(struct snd_dma_buffer *dmab)
{
#ifdef CONFIG_X86
if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC)
set_memory_wb((unsigned long)dmab->area,
PAGE_ALIGN(dmab->bytes) >> PAGE_SHIFT);
#endif
dma_free_coherent(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
}
#ifdef CONFIG_GENERIC_ALLOCATOR
/**
* snd_malloc_dev_iram - allocate memory from on-chip internal ram
* @dmab: buffer allocation record to store the allocated data
* @size: number of bytes to allocate from the iram
*
* This function requires iram phandle provided via of_node
*/
static void snd_malloc_dev_iram(struct snd_dma_buffer *dmab, size_t size)
{
struct device *dev = dmab->dev.dev;
struct gen_pool *pool = NULL;
dmab->area = NULL;
dmab->addr = 0;
if (dev->of_node)
pool = of_gen_pool_get(dev->of_node, "iram", 0);
if (!pool)
return;
/* Assign the pool into private_data field */
dmab->private_data = pool;
dmab->area = gen_pool_dma_alloc_align(pool, size, &dmab->addr,
PAGE_SIZE);
}
/**
* snd_free_dev_iram - free allocated specific memory from on-chip internal ram
* @dmab: buffer allocation record to store the allocated data
*/
static void snd_free_dev_iram(struct snd_dma_buffer *dmab)
{
struct gen_pool *pool = dmab->private_data;
if (pool && dmab->area)
gen_pool_free(pool, (unsigned long)dmab->area, dmab->bytes);
}
#endif /* CONFIG_GENERIC_ALLOCATOR */
#endif /* CONFIG_HAS_DMA */
/*
*
* ALSA generic memory management
*
*/
static inline gfp_t snd_mem_get_gfp_flags(const struct device *dev,
gfp_t default_gfp)
{
if (!dev)
return default_gfp;
else
return (__force gfp_t)(unsigned long)dev;
}
/**
* snd_dma_alloc_pages - allocate the buffer area according to the given type
* @type: the DMA buffer type
* @device: the device pointer
* @size: the buffer size to allocate
* @dmab: buffer allocation record to store the allocated data
*
* Calls the memory-allocator function for the corresponding
* buffer type.
*
* Return: Zero if the buffer with the given size is allocated successfully,
* otherwise a negative value on error.
*/
int snd_dma_alloc_pages(int type, struct device *device, size_t size,
struct snd_dma_buffer *dmab)
{
gfp_t gfp;
if (WARN_ON(!size))
return -ENXIO;
if (WARN_ON(!dmab))
return -ENXIO;
size = PAGE_ALIGN(size);
dmab->dev.type = type;
dmab->dev.dev = device;
dmab->bytes = 0;
dmab->area = NULL;
dmab->addr = 0;
dmab->private_data = NULL;
switch (type) {
case SNDRV_DMA_TYPE_CONTINUOUS:
gfp = snd_mem_get_gfp_flags(device, GFP_KERNEL);
dmab->area = alloc_pages_exact(size, gfp);
break;
case SNDRV_DMA_TYPE_VMALLOC:
gfp = snd_mem_get_gfp_flags(device, GFP_KERNEL | __GFP_HIGHMEM);
dmab->area = __vmalloc(size, gfp);
break;
#ifdef CONFIG_HAS_DMA
#ifdef CONFIG_GENERIC_ALLOCATOR
case SNDRV_DMA_TYPE_DEV_IRAM:
snd_malloc_dev_iram(dmab, size);
if (dmab->area)
break;
/* Internal memory might have limited size and no enough space,
* so if we fail to malloc, try to fetch memory traditionally.
*/
dmab->dev.type = SNDRV_DMA_TYPE_DEV;
fallthrough;
#endif /* CONFIG_GENERIC_ALLOCATOR */
case SNDRV_DMA_TYPE_DEV:
case SNDRV_DMA_TYPE_DEV_UC:
snd_malloc_dev_pages(dmab, size);
break;
#endif
#ifdef CONFIG_SND_DMA_SGBUF
case SNDRV_DMA_TYPE_DEV_SG:
case SNDRV_DMA_TYPE_DEV_UC_SG:
snd_malloc_sgbuf_pages(device, size, dmab, NULL);
break;
#endif
default:
pr_err("snd-malloc: invalid device type %d\n", type);
return -ENXIO;
}
if (! dmab->area)
return -ENOMEM;
dmab->bytes = size;
return 0;
}
EXPORT_SYMBOL(snd_dma_alloc_pages);
/**
* snd_dma_alloc_pages_fallback - allocate the buffer area according to the given type with fallback
* @type: the DMA buffer type
* @device: the device pointer
* @size: the buffer size to allocate
* @dmab: buffer allocation record to store the allocated data
*
* Calls the memory-allocator function for the corresponding
* buffer type. When no space is left, this function reduces the size and
* tries to allocate again. The size actually allocated is stored in
* res_size argument.
*
* Return: Zero if the buffer with the given size is allocated successfully,
* otherwise a negative value on error.
*/
int snd_dma_alloc_pages_fallback(int type, struct device *device, size_t size,
struct snd_dma_buffer *dmab)
{
int err;
while ((err = snd_dma_alloc_pages(type, device, size, dmab)) < 0) {
if (err != -ENOMEM)
return err;
if (size <= PAGE_SIZE)
return -ENOMEM;
size >>= 1;
size = PAGE_SIZE << get_order(size);
}
if (! dmab->area)
return -ENOMEM;
return 0;
}
EXPORT_SYMBOL(snd_dma_alloc_pages_fallback);
/**
* snd_dma_free_pages - release the allocated buffer
* @dmab: the buffer allocation record to release
*
* Releases the allocated buffer via snd_dma_alloc_pages().
*/
void snd_dma_free_pages(struct snd_dma_buffer *dmab)
{
switch (dmab->dev.type) {
case SNDRV_DMA_TYPE_CONTINUOUS:
free_pages_exact(dmab->area, dmab->bytes);
break;
case SNDRV_DMA_TYPE_VMALLOC:
vfree(dmab->area);
break;
#ifdef CONFIG_HAS_DMA
#ifdef CONFIG_GENERIC_ALLOCATOR
case SNDRV_DMA_TYPE_DEV_IRAM:
snd_free_dev_iram(dmab);
break;
#endif /* CONFIG_GENERIC_ALLOCATOR */
case SNDRV_DMA_TYPE_DEV:
case SNDRV_DMA_TYPE_DEV_UC:
snd_free_dev_pages(dmab);
break;
#endif
#ifdef CONFIG_SND_DMA_SGBUF
case SNDRV_DMA_TYPE_DEV_SG:
case SNDRV_DMA_TYPE_DEV_UC_SG:
snd_free_sgbuf_pages(dmab);
break;
#endif
default:
pr_err("snd-malloc: invalid device type %d\n", dmab->dev.type);
}
}
EXPORT_SYMBOL(snd_dma_free_pages);