linux/kernel/dma/pool.c
Nicolas Saenz Julienne d9765e41d8 dma-pool: do not allocate pool memory from CMA
There is no guarantee to CMA's placement, so allocating a zone specific
atomic pool from CMA might return memory from a completely different
memory zone. So stop using it.

Fixes: c84dc6e68a ("dma-pool: add additional coherent pools to map to gfp mask")
Reported-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-14 15:46:32 +02:00

289 lines
7.0 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2012 ARM Ltd.
* Copyright (C) 2020 Google LLC
*/
#include <linux/debugfs.h>
#include <linux/dma-direct.h>
#include <linux/dma-noncoherent.h>
#include <linux/init.h>
#include <linux/genalloc.h>
#include <linux/set_memory.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
static struct gen_pool *atomic_pool_dma __ro_after_init;
static unsigned long pool_size_dma;
static struct gen_pool *atomic_pool_dma32 __ro_after_init;
static unsigned long pool_size_dma32;
static struct gen_pool *atomic_pool_kernel __ro_after_init;
static unsigned long pool_size_kernel;
/* Size can be defined by the coherent_pool command line */
static size_t atomic_pool_size;
/* Dynamic background expansion when the atomic pool is near capacity */
static struct work_struct atomic_pool_work;
static int __init early_coherent_pool(char *p)
{
atomic_pool_size = memparse(p, &p);
return 0;
}
early_param("coherent_pool", early_coherent_pool);
static void __init dma_atomic_pool_debugfs_init(void)
{
struct dentry *root;
root = debugfs_create_dir("dma_pools", NULL);
if (IS_ERR_OR_NULL(root))
return;
debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
}
static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
{
if (gfp & __GFP_DMA)
pool_size_dma += size;
else if (gfp & __GFP_DMA32)
pool_size_dma32 += size;
else
pool_size_kernel += size;
}
static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
gfp_t gfp)
{
unsigned int order;
struct page *page;
void *addr;
int ret = -ENOMEM;
/* Cannot allocate larger than MAX_ORDER-1 */
order = min(get_order(pool_size), MAX_ORDER-1);
do {
pool_size = 1 << (PAGE_SHIFT + order);
page = alloc_pages(gfp, order);
} while (!page && order-- > 0);
if (!page)
goto out;
arch_dma_prep_coherent(page, pool_size);
#ifdef CONFIG_DMA_DIRECT_REMAP
addr = dma_common_contiguous_remap(page, pool_size,
pgprot_dmacoherent(PAGE_KERNEL),
__builtin_return_address(0));
if (!addr)
goto free_page;
#else
addr = page_to_virt(page);
#endif
/*
* Memory in the atomic DMA pools must be unencrypted, the pools do not
* shrink so no re-encryption occurs in dma_direct_free_pages().
*/
ret = set_memory_decrypted((unsigned long)page_to_virt(page),
1 << order);
if (ret)
goto remove_mapping;
ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),
pool_size, NUMA_NO_NODE);
if (ret)
goto encrypt_mapping;
dma_atomic_pool_size_add(gfp, pool_size);
return 0;
encrypt_mapping:
ret = set_memory_encrypted((unsigned long)page_to_virt(page),
1 << order);
if (WARN_ON_ONCE(ret)) {
/* Decrypt succeeded but encrypt failed, purposely leak */
goto out;
}
remove_mapping:
#ifdef CONFIG_DMA_DIRECT_REMAP
dma_common_free_remap(addr, pool_size);
#endif
free_page: __maybe_unused
__free_pages(page, order);
out:
return ret;
}
static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp)
{
if (pool && gen_pool_avail(pool) < atomic_pool_size)
atomic_pool_expand(pool, gen_pool_size(pool), gfp);
}
static void atomic_pool_work_fn(struct work_struct *work)
{
if (IS_ENABLED(CONFIG_ZONE_DMA))
atomic_pool_resize(atomic_pool_dma,
GFP_KERNEL | GFP_DMA);
if (IS_ENABLED(CONFIG_ZONE_DMA32))
atomic_pool_resize(atomic_pool_dma32,
GFP_KERNEL | GFP_DMA32);
atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);
}
static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
gfp_t gfp)
{
struct gen_pool *pool;
int ret;
pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
if (!pool)
return NULL;
gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
ret = atomic_pool_expand(pool, pool_size, gfp);
if (ret) {
gen_pool_destroy(pool);
pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
pool_size >> 10, &gfp);
return NULL;
}
pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
gen_pool_size(pool) >> 10, &gfp);
return pool;
}
static int __init dma_atomic_pool_init(void)
{
int ret = 0;
/*
* If coherent_pool was not used on the command line, default the pool
* sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
*/
if (!atomic_pool_size) {
unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
}
INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);
atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
GFP_KERNEL);
if (!atomic_pool_kernel)
ret = -ENOMEM;
if (IS_ENABLED(CONFIG_ZONE_DMA)) {
atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
GFP_KERNEL | GFP_DMA);
if (!atomic_pool_dma)
ret = -ENOMEM;
}
if (IS_ENABLED(CONFIG_ZONE_DMA32)) {
atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,
GFP_KERNEL | GFP_DMA32);
if (!atomic_pool_dma32)
ret = -ENOMEM;
}
dma_atomic_pool_debugfs_init();
return ret;
}
postcore_initcall(dma_atomic_pool_init);
static inline struct gen_pool *dma_guess_pool_from_device(struct device *dev)
{
u64 phys_mask;
gfp_t gfp;
gfp = dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
&phys_mask);
if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp == GFP_DMA)
return atomic_pool_dma;
if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp == GFP_DMA32)
return atomic_pool_dma32;
return atomic_pool_kernel;
}
static inline struct gen_pool *dma_get_safer_pool(struct gen_pool *bad_pool)
{
if (bad_pool == atomic_pool_kernel)
return atomic_pool_dma32 ? : atomic_pool_dma;
if (bad_pool == atomic_pool_dma32)
return atomic_pool_dma;
return NULL;
}
static inline struct gen_pool *dma_guess_pool(struct device *dev,
struct gen_pool *bad_pool)
{
if (bad_pool)
return dma_get_safer_pool(bad_pool);
return dma_guess_pool_from_device(dev);
}
void *dma_alloc_from_pool(struct device *dev, size_t size,
struct page **ret_page, gfp_t flags)
{
struct gen_pool *pool = NULL;
unsigned long val = 0;
void *ptr = NULL;
phys_addr_t phys;
while (1) {
pool = dma_guess_pool(dev, pool);
if (!pool) {
WARN(1, "Failed to get suitable pool for %s\n",
dev_name(dev));
break;
}
val = gen_pool_alloc(pool, size);
if (!val)
continue;
phys = gen_pool_virt_to_phys(pool, val);
if (dma_coherent_ok(dev, phys, size))
break;
gen_pool_free(pool, val, size);
val = 0;
}
if (val) {
*ret_page = pfn_to_page(__phys_to_pfn(phys));
ptr = (void *)val;
memset(ptr, 0, size);
if (gen_pool_avail(pool) < atomic_pool_size)
schedule_work(&atomic_pool_work);
}
return ptr;
}
bool dma_free_from_pool(struct device *dev, void *start, size_t size)
{
struct gen_pool *pool = NULL;
while (1) {
pool = dma_guess_pool(dev, pool);
if (!pool)
return false;
if (gen_pool_has_addr(pool, (unsigned long)start, size)) {
gen_pool_free(pool, (unsigned long)start, size);
return true;
}
}
}