linux/kernel/dma/swiotlb.c
Linus Torvalds daa121128a dma-mapping updates for Linux 6.10
- optimize DMA sync calls when they are no-ops (Alexander Lobakin)
  - fix swiotlb padding for untrusted devices (Michael Kelley)
  - add documentation for swiotb (Michael Kelley)
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Merge tag 'dma-mapping-6.10-2024-05-20' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - optimize DMA sync calls when they are no-ops (Alexander Lobakin)

 - fix swiotlb padding for untrusted devices (Michael Kelley)

 - add documentation for swiotb (Michael Kelley)

* tag 'dma-mapping-6.10-2024-05-20' of git://git.infradead.org/users/hch/dma-mapping:
  dma: fix DMA sync for drivers not calling dma_set_mask*()
  xsk: use generic DMA sync shortcut instead of a custom one
  page_pool: check for DMA sync shortcut earlier
  page_pool: don't use driver-set flags field directly
  page_pool: make sure frag API fields don't span between cachelines
  iommu/dma: avoid expensive indirect calls for sync operations
  dma: avoid redundant calls for sync operations
  dma: compile-out DMA sync op calls when not used
  iommu/dma: fix zeroing of bounce buffer padding used by untrusted devices
  swiotlb: remove alloc_size argument to swiotlb_tbl_map_single()
  Documentation/core-api: add swiotlb documentation
2024-05-20 10:23:39 -07:00

1878 lines
53 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Dynamic DMA mapping support.
*
* This implementation is a fallback for platforms that do not support
* I/O TLBs (aka DMA address translation hardware).
* Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com>
* Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com>
* Copyright (C) 2000, 2003 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*
* 03/05/07 davidm Switch from PCI-DMA to generic device DMA API.
* 00/12/13 davidm Rename to swiotlb.c and add mark_clean() to avoid
* unnecessary i-cache flushing.
* 04/07/.. ak Better overflow handling. Assorted fixes.
* 05/09/10 linville Add support for syncing ranges, support syncing for
* DMA_BIDIRECTIONAL mappings, miscellaneous cleanup.
* 08/12/11 beckyb Add highmem support
*/
#define pr_fmt(fmt) "software IO TLB: " fmt
#include <linux/cache.h>
#include <linux/cc_platform.h>
#include <linux/ctype.h>
#include <linux/debugfs.h>
#include <linux/dma-direct.h>
#include <linux/dma-map-ops.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/io.h>
#include <linux/iommu-helper.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/pfn.h>
#include <linux/rculist.h>
#include <linux/scatterlist.h>
#include <linux/set_memory.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/swiotlb.h>
#include <linux/types.h>
#ifdef CONFIG_DMA_RESTRICTED_POOL
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/of_reserved_mem.h>
#include <linux/slab.h>
#endif
#define CREATE_TRACE_POINTS
#include <trace/events/swiotlb.h>
#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
/*
* Minimum IO TLB size to bother booting with. Systems with mainly
* 64bit capable cards will only lightly use the swiotlb. If we can't
* allocate a contiguous 1MB, we're probably in trouble anyway.
*/
#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
/**
* struct io_tlb_slot - IO TLB slot descriptor
* @orig_addr: The original address corresponding to a mapped entry.
* @alloc_size: Size of the allocated buffer.
* @list: The free list describing the number of free entries available
* from each index.
* @pad_slots: Number of preceding padding slots. Valid only in the first
* allocated non-padding slot.
*/
struct io_tlb_slot {
phys_addr_t orig_addr;
size_t alloc_size;
unsigned short list;
unsigned short pad_slots;
};
static bool swiotlb_force_bounce;
static bool swiotlb_force_disable;
#ifdef CONFIG_SWIOTLB_DYNAMIC
static void swiotlb_dyn_alloc(struct work_struct *work);
static struct io_tlb_mem io_tlb_default_mem = {
.lock = __SPIN_LOCK_UNLOCKED(io_tlb_default_mem.lock),
.pools = LIST_HEAD_INIT(io_tlb_default_mem.pools),
.dyn_alloc = __WORK_INITIALIZER(io_tlb_default_mem.dyn_alloc,
swiotlb_dyn_alloc),
};
#else /* !CONFIG_SWIOTLB_DYNAMIC */
static struct io_tlb_mem io_tlb_default_mem;
#endif /* CONFIG_SWIOTLB_DYNAMIC */
static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT;
static unsigned long default_nareas;
/**
* struct io_tlb_area - IO TLB memory area descriptor
*
* This is a single area with a single lock.
*
* @used: The number of used IO TLB block.
* @index: The slot index to start searching in this area for next round.
* @lock: The lock to protect the above data structures in the map and
* unmap calls.
*/
struct io_tlb_area {
unsigned long used;
unsigned int index;
spinlock_t lock;
};
/*
* Round up number of slabs to the next power of 2. The last area is going
* be smaller than the rest if default_nslabs is not power of two.
* The number of slot in an area should be a multiple of IO_TLB_SEGSIZE,
* otherwise a segment may span two or more areas. It conflicts with free
* contiguous slots tracking: free slots are treated contiguous no matter
* whether they cross an area boundary.
*
* Return true if default_nslabs is rounded up.
*/
static bool round_up_default_nslabs(void)
{
if (!default_nareas)
return false;
if (default_nslabs < IO_TLB_SEGSIZE * default_nareas)
default_nslabs = IO_TLB_SEGSIZE * default_nareas;
else if (is_power_of_2(default_nslabs))
return false;
default_nslabs = roundup_pow_of_two(default_nslabs);
return true;
}
/**
* swiotlb_adjust_nareas() - adjust the number of areas and slots
* @nareas: Desired number of areas. Zero is treated as 1.
*
* Adjust the default number of areas in a memory pool.
* The default size of the memory pool may also change to meet minimum area
* size requirements.
*/
static void swiotlb_adjust_nareas(unsigned int nareas)
{
if (!nareas)
nareas = 1;
else if (!is_power_of_2(nareas))
nareas = roundup_pow_of_two(nareas);
default_nareas = nareas;
pr_info("area num %d.\n", nareas);
if (round_up_default_nslabs())
pr_info("SWIOTLB bounce buffer size roundup to %luMB",
(default_nslabs << IO_TLB_SHIFT) >> 20);
}
/**
* limit_nareas() - get the maximum number of areas for a given memory pool size
* @nareas: Desired number of areas.
* @nslots: Total number of slots in the memory pool.
*
* Limit the number of areas to the maximum possible number of areas in
* a memory pool of the given size.
*
* Return: Maximum possible number of areas.
*/
static unsigned int limit_nareas(unsigned int nareas, unsigned long nslots)
{
if (nslots < nareas * IO_TLB_SEGSIZE)
return nslots / IO_TLB_SEGSIZE;
return nareas;
}
static int __init
setup_io_tlb_npages(char *str)
{
if (isdigit(*str)) {
/* avoid tail segment of size < IO_TLB_SEGSIZE */
default_nslabs =
ALIGN(simple_strtoul(str, &str, 0), IO_TLB_SEGSIZE);
}
if (*str == ',')
++str;
if (isdigit(*str))
swiotlb_adjust_nareas(simple_strtoul(str, &str, 0));
if (*str == ',')
++str;
if (!strcmp(str, "force"))
swiotlb_force_bounce = true;
else if (!strcmp(str, "noforce"))
swiotlb_force_disable = true;
return 0;
}
early_param("swiotlb", setup_io_tlb_npages);
unsigned long swiotlb_size_or_default(void)
{
return default_nslabs << IO_TLB_SHIFT;
}
void __init swiotlb_adjust_size(unsigned long size)
{
/*
* If swiotlb parameter has not been specified, give a chance to
* architectures such as those supporting memory encryption to
* adjust/expand SWIOTLB size for their use.
*/
if (default_nslabs != IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT)
return;
size = ALIGN(size, IO_TLB_SIZE);
default_nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
if (round_up_default_nslabs())
size = default_nslabs << IO_TLB_SHIFT;
pr_info("SWIOTLB bounce buffer size adjusted to %luMB", size >> 20);
}
void swiotlb_print_info(void)
{
struct io_tlb_pool *mem = &io_tlb_default_mem.defpool;
if (!mem->nslabs) {
pr_warn("No low mem\n");
return;
}
pr_info("mapped [mem %pa-%pa] (%luMB)\n", &mem->start, &mem->end,
(mem->nslabs << IO_TLB_SHIFT) >> 20);
}
static inline unsigned long io_tlb_offset(unsigned long val)
{
return val & (IO_TLB_SEGSIZE - 1);
}
static inline unsigned long nr_slots(u64 val)
{
return DIV_ROUND_UP(val, IO_TLB_SIZE);
}
/*
* Early SWIOTLB allocation may be too early to allow an architecture to
* perform the desired operations. This function allows the architecture to
* call SWIOTLB when the operations are possible. It needs to be called
* before the SWIOTLB memory is used.
*/
void __init swiotlb_update_mem_attributes(void)
{
struct io_tlb_pool *mem = &io_tlb_default_mem.defpool;
unsigned long bytes;
if (!mem->nslabs || mem->late_alloc)
return;
bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT);
set_memory_decrypted((unsigned long)mem->vaddr, bytes >> PAGE_SHIFT);
}
static void swiotlb_init_io_tlb_pool(struct io_tlb_pool *mem, phys_addr_t start,
unsigned long nslabs, bool late_alloc, unsigned int nareas)
{
void *vaddr = phys_to_virt(start);
unsigned long bytes = nslabs << IO_TLB_SHIFT, i;
mem->nslabs = nslabs;
mem->start = start;
mem->end = mem->start + bytes;
mem->late_alloc = late_alloc;
mem->nareas = nareas;
mem->area_nslabs = nslabs / mem->nareas;
for (i = 0; i < mem->nareas; i++) {
spin_lock_init(&mem->areas[i].lock);
mem->areas[i].index = 0;
mem->areas[i].used = 0;
}
for (i = 0; i < mem->nslabs; i++) {
mem->slots[i].list = min(IO_TLB_SEGSIZE - io_tlb_offset(i),
mem->nslabs - i);
mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
mem->slots[i].alloc_size = 0;
mem->slots[i].pad_slots = 0;
}
memset(vaddr, 0, bytes);
mem->vaddr = vaddr;
return;
}
/**
* add_mem_pool() - add a memory pool to the allocator
* @mem: Software IO TLB allocator.
* @pool: Memory pool to be added.
*/
static void add_mem_pool(struct io_tlb_mem *mem, struct io_tlb_pool *pool)
{
#ifdef CONFIG_SWIOTLB_DYNAMIC
spin_lock(&mem->lock);
list_add_rcu(&pool->node, &mem->pools);
mem->nslabs += pool->nslabs;
spin_unlock(&mem->lock);
#else
mem->nslabs = pool->nslabs;
#endif
}
static void __init *swiotlb_memblock_alloc(unsigned long nslabs,
unsigned int flags,
int (*remap)(void *tlb, unsigned long nslabs))
{
size_t bytes = PAGE_ALIGN(nslabs << IO_TLB_SHIFT);
void *tlb;
/*
* By default allocate the bounce buffer memory from low memory, but
* allow to pick a location everywhere for hypervisors with guest
* memory encryption.
*/
if (flags & SWIOTLB_ANY)
tlb = memblock_alloc(bytes, PAGE_SIZE);
else
tlb = memblock_alloc_low(bytes, PAGE_SIZE);
if (!tlb) {
pr_warn("%s: Failed to allocate %zu bytes tlb structure\n",
__func__, bytes);
return NULL;
}
if (remap && remap(tlb, nslabs) < 0) {
memblock_free(tlb, PAGE_ALIGN(bytes));
pr_warn("%s: Failed to remap %zu bytes\n", __func__, bytes);
return NULL;
}
return tlb;
}
/*
* Statically reserve bounce buffer space and initialize bounce buffer data
* structures for the software IO TLB used to implement the DMA API.
*/
void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
int (*remap)(void *tlb, unsigned long nslabs))
{
struct io_tlb_pool *mem = &io_tlb_default_mem.defpool;
unsigned long nslabs;
unsigned int nareas;
size_t alloc_size;
void *tlb;
if (!addressing_limit && !swiotlb_force_bounce)
return;
if (swiotlb_force_disable)
return;
io_tlb_default_mem.force_bounce =
swiotlb_force_bounce || (flags & SWIOTLB_FORCE);
#ifdef CONFIG_SWIOTLB_DYNAMIC
if (!remap)
io_tlb_default_mem.can_grow = true;
if (flags & SWIOTLB_ANY)
io_tlb_default_mem.phys_limit = virt_to_phys(high_memory - 1);
else
io_tlb_default_mem.phys_limit = ARCH_LOW_ADDRESS_LIMIT;
#endif
if (!default_nareas)
swiotlb_adjust_nareas(num_possible_cpus());
nslabs = default_nslabs;
nareas = limit_nareas(default_nareas, nslabs);
while ((tlb = swiotlb_memblock_alloc(nslabs, flags, remap)) == NULL) {
if (nslabs <= IO_TLB_MIN_SLABS)
return;
nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
nareas = limit_nareas(nareas, nslabs);
}
if (default_nslabs != nslabs) {
pr_info("SWIOTLB bounce buffer size adjusted %lu -> %lu slabs",
default_nslabs, nslabs);
default_nslabs = nslabs;
}
alloc_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), nslabs));
mem->slots = memblock_alloc(alloc_size, PAGE_SIZE);
if (!mem->slots) {
pr_warn("%s: Failed to allocate %zu bytes align=0x%lx\n",
__func__, alloc_size, PAGE_SIZE);
return;
}
mem->areas = memblock_alloc(array_size(sizeof(struct io_tlb_area),
nareas), SMP_CACHE_BYTES);
if (!mem->areas) {
pr_warn("%s: Failed to allocate mem->areas.\n", __func__);
return;
}
swiotlb_init_io_tlb_pool(mem, __pa(tlb), nslabs, false, nareas);
add_mem_pool(&io_tlb_default_mem, mem);
if (flags & SWIOTLB_VERBOSE)
swiotlb_print_info();
}
void __init swiotlb_init(bool addressing_limit, unsigned int flags)
{
swiotlb_init_remap(addressing_limit, flags, NULL);
}
/*
* Systems with larger DMA zones (those that don't support ISA) can
* initialize the swiotlb later using the slab allocator if needed.
* This should be just like above, but with some error catching.
*/
int swiotlb_init_late(size_t size, gfp_t gfp_mask,
int (*remap)(void *tlb, unsigned long nslabs))
{
struct io_tlb_pool *mem = &io_tlb_default_mem.defpool;
unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
unsigned int nareas;
unsigned char *vstart = NULL;
unsigned int order, area_order;
bool retried = false;
int rc = 0;
if (io_tlb_default_mem.nslabs)
return 0;
if (swiotlb_force_disable)
return 0;
io_tlb_default_mem.force_bounce = swiotlb_force_bounce;
#ifdef CONFIG_SWIOTLB_DYNAMIC
if (!remap)
io_tlb_default_mem.can_grow = true;
if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp_mask & __GFP_DMA))
io_tlb_default_mem.phys_limit = DMA_BIT_MASK(zone_dma_bits);
else if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp_mask & __GFP_DMA32))
io_tlb_default_mem.phys_limit = DMA_BIT_MASK(32);
else
io_tlb_default_mem.phys_limit = virt_to_phys(high_memory - 1);
#endif
if (!default_nareas)
swiotlb_adjust_nareas(num_possible_cpus());
retry:
order = get_order(nslabs << IO_TLB_SHIFT);
nslabs = SLABS_PER_PAGE << order;
while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
vstart = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN,
order);
if (vstart)
break;
order--;
nslabs = SLABS_PER_PAGE << order;
retried = true;
}
if (!vstart)
return -ENOMEM;
if (remap)
rc = remap(vstart, nslabs);
if (rc) {
free_pages((unsigned long)vstart, order);
nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
if (nslabs < IO_TLB_MIN_SLABS)
return rc;
retried = true;
goto retry;
}
if (retried) {
pr_warn("only able to allocate %ld MB\n",
(PAGE_SIZE << order) >> 20);
}
nareas = limit_nareas(default_nareas, nslabs);
area_order = get_order(array_size(sizeof(*mem->areas), nareas));
mem->areas = (struct io_tlb_area *)
__get_free_pages(GFP_KERNEL | __GFP_ZERO, area_order);
if (!mem->areas)
goto error_area;
mem->slots = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
get_order(array_size(sizeof(*mem->slots), nslabs)));
if (!mem->slots)
goto error_slots;
set_memory_decrypted((unsigned long)vstart,
(nslabs << IO_TLB_SHIFT) >> PAGE_SHIFT);
swiotlb_init_io_tlb_pool(mem, virt_to_phys(vstart), nslabs, true,
nareas);
add_mem_pool(&io_tlb_default_mem, mem);
swiotlb_print_info();
return 0;
error_slots:
free_pages((unsigned long)mem->areas, area_order);
error_area:
free_pages((unsigned long)vstart, order);
return -ENOMEM;
}
void __init swiotlb_exit(void)
{
struct io_tlb_pool *mem = &io_tlb_default_mem.defpool;
unsigned long tbl_vaddr;
size_t tbl_size, slots_size;
unsigned int area_order;
if (swiotlb_force_bounce)
return;
if (!mem->nslabs)
return;
pr_info("tearing down default memory pool\n");
tbl_vaddr = (unsigned long)phys_to_virt(mem->start);
tbl_size = PAGE_ALIGN(mem->end - mem->start);
slots_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), mem->nslabs));
set_memory_encrypted(tbl_vaddr, tbl_size >> PAGE_SHIFT);
if (mem->late_alloc) {
area_order = get_order(array_size(sizeof(*mem->areas),
mem->nareas));
free_pages((unsigned long)mem->areas, area_order);
free_pages(tbl_vaddr, get_order(tbl_size));
free_pages((unsigned long)mem->slots, get_order(slots_size));
} else {
memblock_free_late(__pa(mem->areas),
array_size(sizeof(*mem->areas), mem->nareas));
memblock_free_late(mem->start, tbl_size);
memblock_free_late(__pa(mem->slots), slots_size);
}
memset(mem, 0, sizeof(*mem));
}
#ifdef CONFIG_SWIOTLB_DYNAMIC
/**
* alloc_dma_pages() - allocate pages to be used for DMA
* @gfp: GFP flags for the allocation.
* @bytes: Size of the buffer.
* @phys_limit: Maximum allowed physical address of the buffer.
*
* Allocate pages from the buddy allocator. If successful, make the allocated
* pages decrypted that they can be used for DMA.
*
* Return: Decrypted pages, %NULL on allocation failure, or ERR_PTR(-EAGAIN)
* if the allocated physical address was above @phys_limit.
*/
static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, u64 phys_limit)
{
unsigned int order = get_order(bytes);
struct page *page;
phys_addr_t paddr;
void *vaddr;
page = alloc_pages(gfp, order);
if (!page)
return NULL;
paddr = page_to_phys(page);
if (paddr + bytes - 1 > phys_limit) {
__free_pages(page, order);
return ERR_PTR(-EAGAIN);
}
vaddr = phys_to_virt(paddr);
if (set_memory_decrypted((unsigned long)vaddr, PFN_UP(bytes)))
goto error;
return page;
error:
/* Intentional leak if pages cannot be encrypted again. */
if (!set_memory_encrypted((unsigned long)vaddr, PFN_UP(bytes)))
__free_pages(page, order);
return NULL;
}
/**
* swiotlb_alloc_tlb() - allocate a dynamic IO TLB buffer
* @dev: Device for which a memory pool is allocated.
* @bytes: Size of the buffer.
* @phys_limit: Maximum allowed physical address of the buffer.
* @gfp: GFP flags for the allocation.
*
* Return: Allocated pages, or %NULL on allocation failure.
*/
static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes,
u64 phys_limit, gfp_t gfp)
{
struct page *page;
/*
* Allocate from the atomic pools if memory is encrypted and
* the allocation is atomic, because decrypting may block.
*/
if (!gfpflags_allow_blocking(gfp) && dev && force_dma_unencrypted(dev)) {
void *vaddr;
if (!IS_ENABLED(CONFIG_DMA_COHERENT_POOL))
return NULL;
return dma_alloc_from_pool(dev, bytes, &vaddr, gfp,
dma_coherent_ok);
}
gfp &= ~GFP_ZONEMASK;
if (phys_limit <= DMA_BIT_MASK(zone_dma_bits))
gfp |= __GFP_DMA;
else if (phys_limit <= DMA_BIT_MASK(32))
gfp |= __GFP_DMA32;
while (IS_ERR(page = alloc_dma_pages(gfp, bytes, phys_limit))) {
if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
phys_limit < DMA_BIT_MASK(64) &&
!(gfp & (__GFP_DMA32 | __GFP_DMA)))
gfp |= __GFP_DMA32;
else if (IS_ENABLED(CONFIG_ZONE_DMA) &&
!(gfp & __GFP_DMA))
gfp = (gfp & ~__GFP_DMA32) | __GFP_DMA;
else
return NULL;
}
return page;
}
/**
* swiotlb_free_tlb() - free a dynamically allocated IO TLB buffer
* @vaddr: Virtual address of the buffer.
* @bytes: Size of the buffer.
*/
static void swiotlb_free_tlb(void *vaddr, size_t bytes)
{
if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
dma_free_from_pool(NULL, vaddr, bytes))
return;
/* Intentional leak if pages cannot be encrypted again. */
if (!set_memory_encrypted((unsigned long)vaddr, PFN_UP(bytes)))
__free_pages(virt_to_page(vaddr), get_order(bytes));
}
/**
* swiotlb_alloc_pool() - allocate a new IO TLB memory pool
* @dev: Device for which a memory pool is allocated.
* @minslabs: Minimum number of slabs.
* @nslabs: Desired (maximum) number of slabs.
* @nareas: Number of areas.
* @phys_limit: Maximum DMA buffer physical address.
* @gfp: GFP flags for the allocations.
*
* Allocate and initialize a new IO TLB memory pool. The actual number of
* slabs may be reduced if allocation of @nslabs fails. If even
* @minslabs cannot be allocated, this function fails.
*
* Return: New memory pool, or %NULL on allocation failure.
*/
static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev,
unsigned long minslabs, unsigned long nslabs,
unsigned int nareas, u64 phys_limit, gfp_t gfp)
{
struct io_tlb_pool *pool;
unsigned int slot_order;
struct page *tlb;
size_t pool_size;
size_t tlb_size;
if (nslabs > SLABS_PER_PAGE << MAX_PAGE_ORDER) {
nslabs = SLABS_PER_PAGE << MAX_PAGE_ORDER;
nareas = limit_nareas(nareas, nslabs);
}
pool_size = sizeof(*pool) + array_size(sizeof(*pool->areas), nareas);
pool = kzalloc(pool_size, gfp);
if (!pool)
goto error;
pool->areas = (void *)pool + sizeof(*pool);
tlb_size = nslabs << IO_TLB_SHIFT;
while (!(tlb = swiotlb_alloc_tlb(dev, tlb_size, phys_limit, gfp))) {
if (nslabs <= minslabs)
goto error_tlb;
nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);
nareas = limit_nareas(nareas, nslabs);
tlb_size = nslabs << IO_TLB_SHIFT;
}
slot_order = get_order(array_size(sizeof(*pool->slots), nslabs));
pool->slots = (struct io_tlb_slot *)
__get_free_pages(gfp, slot_order);
if (!pool->slots)
goto error_slots;
swiotlb_init_io_tlb_pool(pool, page_to_phys(tlb), nslabs, true, nareas);
return pool;
error_slots:
swiotlb_free_tlb(page_address(tlb), tlb_size);
error_tlb:
kfree(pool);
error:
return NULL;
}
/**
* swiotlb_dyn_alloc() - dynamic memory pool allocation worker
* @work: Pointer to dyn_alloc in struct io_tlb_mem.
*/
static void swiotlb_dyn_alloc(struct work_struct *work)
{
struct io_tlb_mem *mem =
container_of(work, struct io_tlb_mem, dyn_alloc);
struct io_tlb_pool *pool;
pool = swiotlb_alloc_pool(NULL, IO_TLB_MIN_SLABS, default_nslabs,
default_nareas, mem->phys_limit, GFP_KERNEL);
if (!pool) {
pr_warn_ratelimited("Failed to allocate new pool");
return;
}
add_mem_pool(mem, pool);
}
/**
* swiotlb_dyn_free() - RCU callback to free a memory pool
* @rcu: RCU head in the corresponding struct io_tlb_pool.
*/
static void swiotlb_dyn_free(struct rcu_head *rcu)
{
struct io_tlb_pool *pool = container_of(rcu, struct io_tlb_pool, rcu);
size_t slots_size = array_size(sizeof(*pool->slots), pool->nslabs);
size_t tlb_size = pool->end - pool->start;
free_pages((unsigned long)pool->slots, get_order(slots_size));
swiotlb_free_tlb(pool->vaddr, tlb_size);
kfree(pool);
}
/**
* swiotlb_find_pool() - find the IO TLB pool for a physical address
* @dev: Device which has mapped the DMA buffer.
* @paddr: Physical address within the DMA buffer.
*
* Find the IO TLB memory pool descriptor which contains the given physical
* address, if any.
*
* Return: Memory pool which contains @paddr, or %NULL if none.
*/
struct io_tlb_pool *swiotlb_find_pool(struct device *dev, phys_addr_t paddr)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_pool *pool;
rcu_read_lock();
list_for_each_entry_rcu(pool, &mem->pools, node) {
if (paddr >= pool->start && paddr < pool->end)
goto out;
}
list_for_each_entry_rcu(pool, &dev->dma_io_tlb_pools, node) {
if (paddr >= pool->start && paddr < pool->end)
goto out;
}
pool = NULL;
out:
rcu_read_unlock();
return pool;
}
/**
* swiotlb_del_pool() - remove an IO TLB pool from a device
* @dev: Owning device.
* @pool: Memory pool to be removed.
*/
static void swiotlb_del_pool(struct device *dev, struct io_tlb_pool *pool)
{
unsigned long flags;
spin_lock_irqsave(&dev->dma_io_tlb_lock, flags);
list_del_rcu(&pool->node);
spin_unlock_irqrestore(&dev->dma_io_tlb_lock, flags);
call_rcu(&pool->rcu, swiotlb_dyn_free);
}
#endif /* CONFIG_SWIOTLB_DYNAMIC */
/**
* swiotlb_dev_init() - initialize swiotlb fields in &struct device
* @dev: Device to be initialized.
*/
void swiotlb_dev_init(struct device *dev)
{
dev->dma_io_tlb_mem = &io_tlb_default_mem;
#ifdef CONFIG_SWIOTLB_DYNAMIC
INIT_LIST_HEAD(&dev->dma_io_tlb_pools);
spin_lock_init(&dev->dma_io_tlb_lock);
dev->dma_uses_io_tlb = false;
#endif
}
/**
* swiotlb_align_offset() - Get required offset into an IO TLB allocation.
* @dev: Owning device.
* @align_mask: Allocation alignment mask.
* @addr: DMA address.
*
* Return the minimum offset from the start of an IO TLB allocation which is
* required for a given buffer address and allocation alignment to keep the
* device happy.
*
* First, the address bits covered by min_align_mask must be identical in the
* original address and the bounce buffer address. High bits are preserved by
* choosing a suitable IO TLB slot, but bits below IO_TLB_SHIFT require extra
* padding bytes before the bounce buffer.
*
* Second, @align_mask specifies which bits of the first allocated slot must
* be zero. This may require allocating additional padding slots, and then the
* offset (in bytes) from the first such padding slot is returned.
*/
static unsigned int swiotlb_align_offset(struct device *dev,
unsigned int align_mask, u64 addr)
{
return addr & dma_get_min_align_mask(dev) &
(align_mask | (IO_TLB_SIZE - 1));
}
/*
* Bounce: copy the swiotlb buffer from or back to the original dma location
*/
static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size,
enum dma_data_direction dir)
{
struct io_tlb_pool *mem = swiotlb_find_pool(dev, tlb_addr);
int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT;
phys_addr_t orig_addr = mem->slots[index].orig_addr;
size_t alloc_size = mem->slots[index].alloc_size;
unsigned long pfn = PFN_DOWN(orig_addr);
unsigned char *vaddr = mem->vaddr + tlb_addr - mem->start;
int tlb_offset;
if (orig_addr == INVALID_PHYS_ADDR)
return;
/*
* It's valid for tlb_offset to be negative. This can happen when the
* "offset" returned by swiotlb_align_offset() is non-zero, and the
* tlb_addr is pointing within the first "offset" bytes of the second
* or subsequent slots of the allocated swiotlb area. While it's not
* valid for tlb_addr to be pointing within the first "offset" bytes
* of the first slot, there's no way to check for such an error since
* this function can't distinguish the first slot from the second and
* subsequent slots.
*/
tlb_offset = (tlb_addr & (IO_TLB_SIZE - 1)) -
swiotlb_align_offset(dev, 0, orig_addr);
orig_addr += tlb_offset;
alloc_size -= tlb_offset;
if (size > alloc_size) {
dev_WARN_ONCE(dev, 1,
"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n",
alloc_size, size);
size = alloc_size;
}
if (PageHighMem(pfn_to_page(pfn))) {
unsigned int offset = orig_addr & ~PAGE_MASK;
struct page *page;
unsigned int sz = 0;
unsigned long flags;
while (size) {
sz = min_t(size_t, PAGE_SIZE - offset, size);
local_irq_save(flags);
page = pfn_to_page(pfn);
if (dir == DMA_TO_DEVICE)
memcpy_from_page(vaddr, page, offset, sz);
else
memcpy_to_page(page, offset, vaddr, sz);
local_irq_restore(flags);
size -= sz;
pfn++;
vaddr += sz;
offset = 0;
}
} else if (dir == DMA_TO_DEVICE) {
memcpy(vaddr, phys_to_virt(orig_addr), size);
} else {
memcpy(phys_to_virt(orig_addr), vaddr, size);
}
}
static inline phys_addr_t slot_addr(phys_addr_t start, phys_addr_t idx)
{
return start + (idx << IO_TLB_SHIFT);
}
/*
* Carefully handle integer overflow which can occur when boundary_mask == ~0UL.
*/
static inline unsigned long get_max_slots(unsigned long boundary_mask)
{
return (boundary_mask >> IO_TLB_SHIFT) + 1;
}
static unsigned int wrap_area_index(struct io_tlb_pool *mem, unsigned int index)
{
if (index >= mem->area_nslabs)
return 0;
return index;
}
/*
* Track the total used slots with a global atomic value in order to have
* correct information to determine the high water mark. The mem_used()
* function gives imprecise results because there's no locking across
* multiple areas.
*/
#ifdef CONFIG_DEBUG_FS
static void inc_used_and_hiwater(struct io_tlb_mem *mem, unsigned int nslots)
{
unsigned long old_hiwater, new_used;
new_used = atomic_long_add_return(nslots, &mem->total_used);
old_hiwater = atomic_long_read(&mem->used_hiwater);
do {
if (new_used <= old_hiwater)
break;
} while (!atomic_long_try_cmpxchg(&mem->used_hiwater,
&old_hiwater, new_used));
}
static void dec_used(struct io_tlb_mem *mem, unsigned int nslots)
{
atomic_long_sub(nslots, &mem->total_used);
}
#else /* !CONFIG_DEBUG_FS */
static void inc_used_and_hiwater(struct io_tlb_mem *mem, unsigned int nslots)
{
}
static void dec_used(struct io_tlb_mem *mem, unsigned int nslots)
{
}
#endif /* CONFIG_DEBUG_FS */
#ifdef CONFIG_SWIOTLB_DYNAMIC
#ifdef CONFIG_DEBUG_FS
static void inc_transient_used(struct io_tlb_mem *mem, unsigned int nslots)
{
atomic_long_add(nslots, &mem->transient_nslabs);
}
static void dec_transient_used(struct io_tlb_mem *mem, unsigned int nslots)
{
atomic_long_sub(nslots, &mem->transient_nslabs);
}
#else /* !CONFIG_DEBUG_FS */
static void inc_transient_used(struct io_tlb_mem *mem, unsigned int nslots)
{
}
static void dec_transient_used(struct io_tlb_mem *mem, unsigned int nslots)
{
}
#endif /* CONFIG_DEBUG_FS */
#endif /* CONFIG_SWIOTLB_DYNAMIC */
/**
* swiotlb_search_pool_area() - search one memory area in one pool
* @dev: Device which maps the buffer.
* @pool: Memory pool to be searched.
* @area_index: Index of the IO TLB memory area to be searched.
* @orig_addr: Original (non-bounced) IO buffer address.
* @alloc_size: Total requested size of the bounce buffer,
* including initial alignment padding.
* @alloc_align_mask: Required alignment of the allocated buffer.
*
* Find a suitable sequence of IO TLB entries for the request and allocate
* a buffer from the given IO TLB memory area.
* This function takes care of locking.
*
* Return: Index of the first allocated slot, or -1 on error.
*/
static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool,
int area_index, phys_addr_t orig_addr, size_t alloc_size,
unsigned int alloc_align_mask)
{
struct io_tlb_area *area = pool->areas + area_index;
unsigned long boundary_mask = dma_get_seg_boundary(dev);
dma_addr_t tbl_dma_addr =
phys_to_dma_unencrypted(dev, pool->start) & boundary_mask;
unsigned long max_slots = get_max_slots(boundary_mask);
unsigned int iotlb_align_mask = dma_get_min_align_mask(dev);
unsigned int nslots = nr_slots(alloc_size), stride;
unsigned int offset = swiotlb_align_offset(dev, 0, orig_addr);
unsigned int index, slots_checked, count = 0, i;
unsigned long flags;
unsigned int slot_base;
unsigned int slot_index;
BUG_ON(!nslots);
BUG_ON(area_index >= pool->nareas);
/*
* Historically, swiotlb allocations >= PAGE_SIZE were guaranteed to be
* page-aligned in the absence of any other alignment requirements.
* 'alloc_align_mask' was later introduced to specify the alignment
* explicitly, however this is passed as zero for streaming mappings
* and so we preserve the old behaviour there in case any drivers are
* relying on it.
*/
if (!alloc_align_mask && !iotlb_align_mask && alloc_size >= PAGE_SIZE)
alloc_align_mask = PAGE_SIZE - 1;
/*
* Ensure that the allocation is at least slot-aligned and update
* 'iotlb_align_mask' to ignore bits that will be preserved when
* offsetting into the allocation.
*/
alloc_align_mask |= (IO_TLB_SIZE - 1);
iotlb_align_mask &= ~alloc_align_mask;
/*
* For mappings with an alignment requirement don't bother looping to
* unaligned slots once we found an aligned one.
*/
stride = get_max_slots(max(alloc_align_mask, iotlb_align_mask));
spin_lock_irqsave(&area->lock, flags);
if (unlikely(nslots > pool->area_nslabs - area->used))
goto not_found;
slot_base = area_index * pool->area_nslabs;
index = area->index;
for (slots_checked = 0; slots_checked < pool->area_nslabs; ) {
phys_addr_t tlb_addr;
slot_index = slot_base + index;
tlb_addr = slot_addr(tbl_dma_addr, slot_index);
if ((tlb_addr & alloc_align_mask) ||
(orig_addr && (tlb_addr & iotlb_align_mask) !=
(orig_addr & iotlb_align_mask))) {
index = wrap_area_index(pool, index + 1);
slots_checked++;
continue;
}
if (!iommu_is_span_boundary(slot_index, nslots,
nr_slots(tbl_dma_addr),
max_slots)) {
if (pool->slots[slot_index].list >= nslots)
goto found;
}
index = wrap_area_index(pool, index + stride);
slots_checked += stride;
}
not_found:
spin_unlock_irqrestore(&area->lock, flags);
return -1;
found:
/*
* If we find a slot that indicates we have 'nslots' number of
* contiguous buffers, we allocate the buffers from that slot onwards
* and set the list of free entries to '0' indicating unavailable.
*/
for (i = slot_index; i < slot_index + nslots; i++) {
pool->slots[i].list = 0;
pool->slots[i].alloc_size = alloc_size - (offset +
((i - slot_index) << IO_TLB_SHIFT));
}
for (i = slot_index - 1;
io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 &&
pool->slots[i].list; i--)
pool->slots[i].list = ++count;
/*
* Update the indices to avoid searching in the next round.
*/
area->index = wrap_area_index(pool, index + nslots);
area->used += nslots;
spin_unlock_irqrestore(&area->lock, flags);
inc_used_and_hiwater(dev->dma_io_tlb_mem, nslots);
return slot_index;
}
#ifdef CONFIG_SWIOTLB_DYNAMIC
/**
* swiotlb_search_area() - search one memory area in all pools
* @dev: Device which maps the buffer.
* @start_cpu: Start CPU number.
* @cpu_offset: Offset from @start_cpu.
* @orig_addr: Original (non-bounced) IO buffer address.
* @alloc_size: Total requested size of the bounce buffer,
* including initial alignment padding.
* @alloc_align_mask: Required alignment of the allocated buffer.
* @retpool: Used memory pool, updated on return.
*
* Search one memory area in all pools for a sequence of slots that match the
* allocation constraints.
*
* Return: Index of the first allocated slot, or -1 on error.
*/
static int swiotlb_search_area(struct device *dev, int start_cpu,
int cpu_offset, phys_addr_t orig_addr, size_t alloc_size,
unsigned int alloc_align_mask, struct io_tlb_pool **retpool)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_pool *pool;
int area_index;
int index = -1;
rcu_read_lock();
list_for_each_entry_rcu(pool, &mem->pools, node) {
if (cpu_offset >= pool->nareas)
continue;
area_index = (start_cpu + cpu_offset) & (pool->nareas - 1);
index = swiotlb_search_pool_area(dev, pool, area_index,
orig_addr, alloc_size,
alloc_align_mask);
if (index >= 0) {
*retpool = pool;
break;
}
}
rcu_read_unlock();
return index;
}
/**
* swiotlb_find_slots() - search for slots in the whole swiotlb
* @dev: Device which maps the buffer.
* @orig_addr: Original (non-bounced) IO buffer address.
* @alloc_size: Total requested size of the bounce buffer,
* including initial alignment padding.
* @alloc_align_mask: Required alignment of the allocated buffer.
* @retpool: Used memory pool, updated on return.
*
* Search through the whole software IO TLB to find a sequence of slots that
* match the allocation constraints.
*
* Return: Index of the first allocated slot, or -1 on error.
*/
static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
size_t alloc_size, unsigned int alloc_align_mask,
struct io_tlb_pool **retpool)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_pool *pool;
unsigned long nslabs;
unsigned long flags;
u64 phys_limit;
int cpu, i;
int index;
if (alloc_size > IO_TLB_SEGSIZE * IO_TLB_SIZE)
return -1;
cpu = raw_smp_processor_id();
for (i = 0; i < default_nareas; ++i) {
index = swiotlb_search_area(dev, cpu, i, orig_addr, alloc_size,
alloc_align_mask, &pool);
if (index >= 0)
goto found;
}
if (!mem->can_grow)
return -1;
schedule_work(&mem->dyn_alloc);
nslabs = nr_slots(alloc_size);
phys_limit = min_not_zero(*dev->dma_mask, dev->bus_dma_limit);
pool = swiotlb_alloc_pool(dev, nslabs, nslabs, 1, phys_limit,
GFP_NOWAIT | __GFP_NOWARN);
if (!pool)
return -1;
index = swiotlb_search_pool_area(dev, pool, 0, orig_addr,
alloc_size, alloc_align_mask);
if (index < 0) {
swiotlb_dyn_free(&pool->rcu);
return -1;
}
pool->transient = true;
spin_lock_irqsave(&dev->dma_io_tlb_lock, flags);
list_add_rcu(&pool->node, &dev->dma_io_tlb_pools);
spin_unlock_irqrestore(&dev->dma_io_tlb_lock, flags);
inc_transient_used(mem, pool->nslabs);
found:
WRITE_ONCE(dev->dma_uses_io_tlb, true);
/*
* The general barrier orders reads and writes against a presumed store
* of the SWIOTLB buffer address by a device driver (to a driver private
* data structure). It serves two purposes.
*
* First, the store to dev->dma_uses_io_tlb must be ordered before the
* presumed store. This guarantees that the returned buffer address
* cannot be passed to another CPU before updating dev->dma_uses_io_tlb.
*
* Second, the load from mem->pools must be ordered before the same
* presumed store. This guarantees that the returned buffer address
* cannot be observed by another CPU before an update of the RCU list
* that was made by swiotlb_dyn_alloc() on a third CPU (cf. multicopy
* atomicity).
*
* See also the comment in is_swiotlb_buffer().
*/
smp_mb();
*retpool = pool;
return index;
}
#else /* !CONFIG_SWIOTLB_DYNAMIC */
static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
size_t alloc_size, unsigned int alloc_align_mask,
struct io_tlb_pool **retpool)
{
struct io_tlb_pool *pool;
int start, i;
int index;
*retpool = pool = &dev->dma_io_tlb_mem->defpool;
i = start = raw_smp_processor_id() & (pool->nareas - 1);
do {
index = swiotlb_search_pool_area(dev, pool, i, orig_addr,
alloc_size, alloc_align_mask);
if (index >= 0)
return index;
if (++i >= pool->nareas)
i = 0;
} while (i != start);
return -1;
}
#endif /* CONFIG_SWIOTLB_DYNAMIC */
#ifdef CONFIG_DEBUG_FS
/**
* mem_used() - get number of used slots in an allocator
* @mem: Software IO TLB allocator.
*
* The result is accurate in this version of the function, because an atomic
* counter is available if CONFIG_DEBUG_FS is set.
*
* Return: Number of used slots.
*/
static unsigned long mem_used(struct io_tlb_mem *mem)
{
return atomic_long_read(&mem->total_used);
}
#else /* !CONFIG_DEBUG_FS */
/**
* mem_pool_used() - get number of used slots in a memory pool
* @pool: Software IO TLB memory pool.
*
* The result is not accurate, see mem_used().
*
* Return: Approximate number of used slots.
*/
static unsigned long mem_pool_used(struct io_tlb_pool *pool)
{
int i;
unsigned long used = 0;
for (i = 0; i < pool->nareas; i++)
used += pool->areas[i].used;
return used;
}
/**
* mem_used() - get number of used slots in an allocator
* @mem: Software IO TLB allocator.
*
* The result is not accurate, because there is no locking of individual
* areas.
*
* Return: Approximate number of used slots.
*/
static unsigned long mem_used(struct io_tlb_mem *mem)
{
#ifdef CONFIG_SWIOTLB_DYNAMIC
struct io_tlb_pool *pool;
unsigned long used = 0;
rcu_read_lock();
list_for_each_entry_rcu(pool, &mem->pools, node)
used += mem_pool_used(pool);
rcu_read_unlock();
return used;
#else
return mem_pool_used(&mem->defpool);
#endif
}
#endif /* CONFIG_DEBUG_FS */
/**
* swiotlb_tbl_map_single() - bounce buffer map a single contiguous physical area
* @dev: Device which maps the buffer.
* @orig_addr: Original (non-bounced) physical IO buffer address
* @mapping_size: Requested size of the actual bounce buffer, excluding
* any pre- or post-padding for alignment
* @alloc_align_mask: Required start and end alignment of the allocated buffer
* @dir: DMA direction
* @attrs: Optional DMA attributes for the map operation
*
* Find and allocate a suitable sequence of IO TLB slots for the request.
* The allocated space starts at an alignment specified by alloc_align_mask,
* and the size of the allocated space is rounded up so that the total amount
* of allocated space is a multiple of (alloc_align_mask + 1). If
* alloc_align_mask is zero, the allocated space may be at any alignment and
* the size is not rounded up.
*
* The returned address is within the allocated space and matches the bits
* of orig_addr that are specified in the DMA min_align_mask for the device. As
* such, this returned address may be offset from the beginning of the allocated
* space. The bounce buffer space starting at the returned address for
* mapping_size bytes is initialized to the contents of the original IO buffer
* area. Any pre-padding (due to an offset) and any post-padding (due to
* rounding-up the size) is not initialized.
*/
phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
size_t mapping_size, unsigned int alloc_align_mask,
enum dma_data_direction dir, unsigned long attrs)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
unsigned int offset;
struct io_tlb_pool *pool;
unsigned int i;
size_t size;
int index;
phys_addr_t tlb_addr;
unsigned short pad_slots;
if (!mem || !mem->nslabs) {
dev_warn_ratelimited(dev,
"Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
return (phys_addr_t)DMA_MAPPING_ERROR;
}
if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
/*
* The default swiotlb memory pool is allocated with PAGE_SIZE
* alignment. If a mapping is requested with larger alignment,
* the mapping may be unable to use the initial slot(s) in all
* sets of IO_TLB_SEGSIZE slots. In such case, a mapping request
* of or near the maximum mapping size would always fail.
*/
dev_WARN_ONCE(dev, alloc_align_mask > ~PAGE_MASK,
"Alloc alignment may prevent fulfilling requests with max mapping_size\n");
offset = swiotlb_align_offset(dev, alloc_align_mask, orig_addr);
size = ALIGN(mapping_size + offset, alloc_align_mask + 1);
index = swiotlb_find_slots(dev, orig_addr, size, alloc_align_mask, &pool);
if (index == -1) {
if (!(attrs & DMA_ATTR_NO_WARN))
dev_warn_ratelimited(dev,
"swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
size, mem->nslabs, mem_used(mem));
return (phys_addr_t)DMA_MAPPING_ERROR;
}
/*
* If dma_skip_sync was set, reset it on first SWIOTLB buffer
* mapping to always sync SWIOTLB buffers.
*/
dma_reset_need_sync(dev);
/*
* Save away the mapping from the original address to the DMA address.
* This is needed when we sync the memory. Then we sync the buffer if
* needed.
*/
pad_slots = offset >> IO_TLB_SHIFT;
offset &= (IO_TLB_SIZE - 1);
index += pad_slots;
pool->slots[index].pad_slots = pad_slots;
for (i = 0; i < (nr_slots(size) - pad_slots); i++)
pool->slots[index + i].orig_addr = slot_addr(orig_addr, i);
tlb_addr = slot_addr(pool->start, index) + offset;
/*
* When the device is writing memory, i.e. dir == DMA_FROM_DEVICE, copy
* the original buffer to the TLB buffer before initiating DMA in order
* to preserve the original's data if the device does a partial write,
* i.e. if the device doesn't overwrite the entire buffer. Preserving
* the original data, even if it's garbage, is necessary to match
* hardware behavior. Use of swiotlb is supposed to be transparent,
* i.e. swiotlb must not corrupt memory by clobbering unwritten bytes.
*/
swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_TO_DEVICE);
return tlb_addr;
}
static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr)
{
struct io_tlb_pool *mem = swiotlb_find_pool(dev, tlb_addr);
unsigned long flags;
unsigned int offset = swiotlb_align_offset(dev, 0, tlb_addr);
int index, nslots, aindex;
struct io_tlb_area *area;
int count, i;
index = (tlb_addr - offset - mem->start) >> IO_TLB_SHIFT;
index -= mem->slots[index].pad_slots;
nslots = nr_slots(mem->slots[index].alloc_size + offset);
aindex = index / mem->area_nslabs;
area = &mem->areas[aindex];
/*
* Return the buffer to the free list by setting the corresponding
* entries to indicate the number of contiguous entries available.
* While returning the entries to the free list, we merge the entries
* with slots below and above the pool being returned.
*/
BUG_ON(aindex >= mem->nareas);
spin_lock_irqsave(&area->lock, flags);
if (index + nslots < ALIGN(index + 1, IO_TLB_SEGSIZE))
count = mem->slots[index + nslots].list;
else
count = 0;
/*
* Step 1: return the slots to the free list, merging the slots with
* superceeding slots
*/
for (i = index + nslots - 1; i >= index; i--) {
mem->slots[i].list = ++count;
mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
mem->slots[i].alloc_size = 0;
mem->slots[i].pad_slots = 0;
}
/*
* Step 2: merge the returned slots with the preceding slots, if
* available (non zero)
*/
for (i = index - 1;
io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 && mem->slots[i].list;
i--)
mem->slots[i].list = ++count;
area->used -= nslots;
spin_unlock_irqrestore(&area->lock, flags);
dec_used(dev->dma_io_tlb_mem, nslots);
}
#ifdef CONFIG_SWIOTLB_DYNAMIC
/**
* swiotlb_del_transient() - delete a transient memory pool
* @dev: Device which mapped the buffer.
* @tlb_addr: Physical address within a bounce buffer.
*
* Check whether the address belongs to a transient SWIOTLB memory pool.
* If yes, then delete the pool.
*
* Return: %true if @tlb_addr belonged to a transient pool that was released.
*/
static bool swiotlb_del_transient(struct device *dev, phys_addr_t tlb_addr)
{
struct io_tlb_pool *pool;
pool = swiotlb_find_pool(dev, tlb_addr);
if (!pool->transient)
return false;
dec_used(dev->dma_io_tlb_mem, pool->nslabs);
swiotlb_del_pool(dev, pool);
dec_transient_used(dev->dma_io_tlb_mem, pool->nslabs);
return true;
}
#else /* !CONFIG_SWIOTLB_DYNAMIC */
static inline bool swiotlb_del_transient(struct device *dev,
phys_addr_t tlb_addr)
{
return false;
}
#endif /* CONFIG_SWIOTLB_DYNAMIC */
/*
* tlb_addr is the physical address of the bounce buffer to unmap.
*/
void swiotlb_tbl_unmap_single(struct device *dev, phys_addr_t tlb_addr,
size_t mapping_size, enum dma_data_direction dir,
unsigned long attrs)
{
/*
* First, sync the memory before unmapping the entry
*/
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_FROM_DEVICE);
if (swiotlb_del_transient(dev, tlb_addr))
return;
swiotlb_release_slots(dev, tlb_addr);
}
void swiotlb_sync_single_for_device(struct device *dev, phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir)
{
if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
swiotlb_bounce(dev, tlb_addr, size, DMA_TO_DEVICE);
else
BUG_ON(dir != DMA_FROM_DEVICE);
}
void swiotlb_sync_single_for_cpu(struct device *dev, phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir)
{
if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
swiotlb_bounce(dev, tlb_addr, size, DMA_FROM_DEVICE);
else
BUG_ON(dir != DMA_TO_DEVICE);
}
/*
* Create a swiotlb mapping for the buffer at @paddr, and in case of DMAing
* to the device copy the data into it as well.
*/
dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
enum dma_data_direction dir, unsigned long attrs)
{
phys_addr_t swiotlb_addr;
dma_addr_t dma_addr;
trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size);
swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, 0, dir, attrs);
if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR)
return DMA_MAPPING_ERROR;
/* Ensure that the address returned is DMA'ble */
dma_addr = phys_to_dma_unencrypted(dev, swiotlb_addr);
if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, dir,
attrs | DMA_ATTR_SKIP_CPU_SYNC);
dev_WARN_ONCE(dev, 1,
"swiotlb addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
&dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
return DMA_MAPPING_ERROR;
}
if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
arch_sync_dma_for_device(swiotlb_addr, size, dir);
return dma_addr;
}
size_t swiotlb_max_mapping_size(struct device *dev)
{
int min_align_mask = dma_get_min_align_mask(dev);
int min_align = 0;
/*
* swiotlb_find_slots() skips slots according to
* min align mask. This affects max mapping size.
* Take it into acount here.
*/
if (min_align_mask)
min_align = roundup(min_align_mask, IO_TLB_SIZE);
return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE - min_align;
}
/**
* is_swiotlb_allocated() - check if the default software IO TLB is initialized
*/
bool is_swiotlb_allocated(void)
{
return io_tlb_default_mem.nslabs;
}
bool is_swiotlb_active(struct device *dev)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
return mem && mem->nslabs;
}
/**
* default_swiotlb_base() - get the base address of the default SWIOTLB
*
* Get the lowest physical address used by the default software IO TLB pool.
*/
phys_addr_t default_swiotlb_base(void)
{
#ifdef CONFIG_SWIOTLB_DYNAMIC
io_tlb_default_mem.can_grow = false;
#endif
return io_tlb_default_mem.defpool.start;
}
/**
* default_swiotlb_limit() - get the address limit of the default SWIOTLB
*
* Get the highest physical address used by the default software IO TLB pool.
*/
phys_addr_t default_swiotlb_limit(void)
{
#ifdef CONFIG_SWIOTLB_DYNAMIC
return io_tlb_default_mem.phys_limit;
#else
return io_tlb_default_mem.defpool.end - 1;
#endif
}
#ifdef CONFIG_DEBUG_FS
#ifdef CONFIG_SWIOTLB_DYNAMIC
static unsigned long mem_transient_used(struct io_tlb_mem *mem)
{
return atomic_long_read(&mem->transient_nslabs);
}
static int io_tlb_transient_used_get(void *data, u64 *val)
{
struct io_tlb_mem *mem = data;
*val = mem_transient_used(mem);
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_io_tlb_transient_used, io_tlb_transient_used_get,
NULL, "%llu\n");
#endif /* CONFIG_SWIOTLB_DYNAMIC */
static int io_tlb_used_get(void *data, u64 *val)
{
struct io_tlb_mem *mem = data;
*val = mem_used(mem);
return 0;
}
static int io_tlb_hiwater_get(void *data, u64 *val)
{
struct io_tlb_mem *mem = data;
*val = atomic_long_read(&mem->used_hiwater);
return 0;
}
static int io_tlb_hiwater_set(void *data, u64 val)
{
struct io_tlb_mem *mem = data;
/* Only allow setting to zero */
if (val != 0)
return -EINVAL;
atomic_long_set(&mem->used_hiwater, val);
return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_io_tlb_used, io_tlb_used_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_io_tlb_hiwater, io_tlb_hiwater_get,
io_tlb_hiwater_set, "%llu\n");
static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem,
const char *dirname)
{
mem->debugfs = debugfs_create_dir(dirname, io_tlb_default_mem.debugfs);
if (!mem->nslabs)
return;
debugfs_create_ulong("io_tlb_nslabs", 0400, mem->debugfs, &mem->nslabs);
debugfs_create_file("io_tlb_used", 0400, mem->debugfs, mem,
&fops_io_tlb_used);
debugfs_create_file("io_tlb_used_hiwater", 0600, mem->debugfs, mem,
&fops_io_tlb_hiwater);
#ifdef CONFIG_SWIOTLB_DYNAMIC
debugfs_create_file("io_tlb_transient_nslabs", 0400, mem->debugfs,
mem, &fops_io_tlb_transient_used);
#endif
}
static int __init swiotlb_create_default_debugfs(void)
{
swiotlb_create_debugfs_files(&io_tlb_default_mem, "swiotlb");
return 0;
}
late_initcall(swiotlb_create_default_debugfs);
#else /* !CONFIG_DEBUG_FS */
static inline void swiotlb_create_debugfs_files(struct io_tlb_mem *mem,
const char *dirname)
{
}
#endif /* CONFIG_DEBUG_FS */
#ifdef CONFIG_DMA_RESTRICTED_POOL
struct page *swiotlb_alloc(struct device *dev, size_t size)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_pool *pool;
phys_addr_t tlb_addr;
unsigned int align;
int index;
if (!mem)
return NULL;
align = (1 << (get_order(size) + PAGE_SHIFT)) - 1;
index = swiotlb_find_slots(dev, 0, size, align, &pool);
if (index == -1)
return NULL;
tlb_addr = slot_addr(pool->start, index);
if (unlikely(!PAGE_ALIGNED(tlb_addr))) {
dev_WARN_ONCE(dev, 1, "Cannot allocate pages from non page-aligned swiotlb addr 0x%pa.\n",
&tlb_addr);
swiotlb_release_slots(dev, tlb_addr);
return NULL;
}
return pfn_to_page(PFN_DOWN(tlb_addr));
}
bool swiotlb_free(struct device *dev, struct page *page, size_t size)
{
phys_addr_t tlb_addr = page_to_phys(page);
if (!is_swiotlb_buffer(dev, tlb_addr))
return false;
swiotlb_release_slots(dev, tlb_addr);
return true;
}
static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
struct device *dev)
{
struct io_tlb_mem *mem = rmem->priv;
unsigned long nslabs = rmem->size >> IO_TLB_SHIFT;
/* Set Per-device io tlb area to one */
unsigned int nareas = 1;
if (PageHighMem(pfn_to_page(PHYS_PFN(rmem->base)))) {
dev_err(dev, "Restricted DMA pool must be accessible within the linear mapping.");
return -EINVAL;
}
/*
* Since multiple devices can share the same pool, the private data,
* io_tlb_mem struct, will be initialized by the first device attached
* to it.
*/
if (!mem) {
struct io_tlb_pool *pool;
mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem)
return -ENOMEM;
pool = &mem->defpool;
pool->slots = kcalloc(nslabs, sizeof(*pool->slots), GFP_KERNEL);
if (!pool->slots) {
kfree(mem);
return -ENOMEM;
}
pool->areas = kcalloc(nareas, sizeof(*pool->areas),
GFP_KERNEL);
if (!pool->areas) {
kfree(pool->slots);
kfree(mem);
return -ENOMEM;
}
set_memory_decrypted((unsigned long)phys_to_virt(rmem->base),
rmem->size >> PAGE_SHIFT);
swiotlb_init_io_tlb_pool(pool, rmem->base, nslabs,
false, nareas);
mem->force_bounce = true;
mem->for_alloc = true;
#ifdef CONFIG_SWIOTLB_DYNAMIC
spin_lock_init(&mem->lock);
INIT_LIST_HEAD_RCU(&mem->pools);
#endif
add_mem_pool(mem, pool);
rmem->priv = mem;
swiotlb_create_debugfs_files(mem, rmem->name);
}
dev->dma_io_tlb_mem = mem;
return 0;
}
static void rmem_swiotlb_device_release(struct reserved_mem *rmem,
struct device *dev)
{
dev->dma_io_tlb_mem = &io_tlb_default_mem;
}
static const struct reserved_mem_ops rmem_swiotlb_ops = {
.device_init = rmem_swiotlb_device_init,
.device_release = rmem_swiotlb_device_release,
};
static int __init rmem_swiotlb_setup(struct reserved_mem *rmem)
{
unsigned long node = rmem->fdt_node;
if (of_get_flat_dt_prop(node, "reusable", NULL) ||
of_get_flat_dt_prop(node, "linux,cma-default", NULL) ||
of_get_flat_dt_prop(node, "linux,dma-default", NULL) ||
of_get_flat_dt_prop(node, "no-map", NULL))
return -EINVAL;
rmem->ops = &rmem_swiotlb_ops;
pr_info("Reserved memory: created restricted DMA pool at %pa, size %ld MiB\n",
&rmem->base, (unsigned long)rmem->size / SZ_1M);
return 0;
}
RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", rmem_swiotlb_setup);
#endif /* CONFIG_DMA_RESTRICTED_POOL */