swh:1:snp:49cd9498d6cccc5e78252c27dcb645bcf7bf0c91
Tip revision: e21a712a9685488f5ce80495b37b9fdbe96c230d authored by Linus Torvalds on 05 August 2019, 01:40:12 UTC
Linux 5.3-rc3
Linux 5.3-rc3
Tip revision: e21a712
dma-iommu.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* A fairly generic DMA-API to IOMMU-API glue layer.
*
* Copyright (C) 2014-2015 ARM Ltd.
*
* based in part on arch/arm/mm/dma-mapping.c:
* Copyright (C) 2000-2004 Russell King
*/
#include <linux/acpi_iort.h>
#include <linux/device.h>
#include <linux/dma-contiguous.h>
#include <linux/dma-iommu.h>
#include <linux/dma-noncoherent.h>
#include <linux/gfp.h>
#include <linux/huge_mm.h>
#include <linux/iommu.h>
#include <linux/iova.h>
#include <linux/irq.h>
#include <linux/mm.h>
#include <linux/pci.h>
#include <linux/scatterlist.h>
#include <linux/vmalloc.h>
struct iommu_dma_msi_page {
struct list_head list;
dma_addr_t iova;
phys_addr_t phys;
};
enum iommu_dma_cookie_type {
IOMMU_DMA_IOVA_COOKIE,
IOMMU_DMA_MSI_COOKIE,
};
struct iommu_dma_cookie {
enum iommu_dma_cookie_type type;
union {
/* Full allocator for IOMMU_DMA_IOVA_COOKIE */
struct iova_domain iovad;
/* Trivial linear page allocator for IOMMU_DMA_MSI_COOKIE */
dma_addr_t msi_iova;
};
struct list_head msi_page_list;
spinlock_t msi_lock;
/* Domain for flush queue callback; NULL if flush queue not in use */
struct iommu_domain *fq_domain;
};
static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie)
{
if (cookie->type == IOMMU_DMA_IOVA_COOKIE)
return cookie->iovad.granule;
return PAGE_SIZE;
}
static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type)
{
struct iommu_dma_cookie *cookie;
cookie = kzalloc(sizeof(*cookie), GFP_KERNEL);
if (cookie) {
spin_lock_init(&cookie->msi_lock);
INIT_LIST_HEAD(&cookie->msi_page_list);
cookie->type = type;
}
return cookie;
}
/**
* iommu_get_dma_cookie - Acquire DMA-API resources for a domain
* @domain: IOMMU domain to prepare for DMA-API usage
*
* IOMMU drivers should normally call this from their domain_alloc
* callback when domain->type == IOMMU_DOMAIN_DMA.
*/
int iommu_get_dma_cookie(struct iommu_domain *domain)
{
if (domain->iova_cookie)
return -EEXIST;
domain->iova_cookie = cookie_alloc(IOMMU_DMA_IOVA_COOKIE);
if (!domain->iova_cookie)
return -ENOMEM;
return 0;
}
EXPORT_SYMBOL(iommu_get_dma_cookie);
/**
* iommu_get_msi_cookie - Acquire just MSI remapping resources
* @domain: IOMMU domain to prepare
* @base: Start address of IOVA region for MSI mappings
*
* Users who manage their own IOVA allocation and do not want DMA API support,
* but would still like to take advantage of automatic MSI remapping, can use
* this to initialise their own domain appropriately. Users should reserve a
* contiguous IOVA region, starting at @base, large enough to accommodate the
* number of PAGE_SIZE mappings necessary to cover every MSI doorbell address
* used by the devices attached to @domain.
*/
int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
{
struct iommu_dma_cookie *cookie;
if (domain->type != IOMMU_DOMAIN_UNMANAGED)
return -EINVAL;
if (domain->iova_cookie)
return -EEXIST;
cookie = cookie_alloc(IOMMU_DMA_MSI_COOKIE);
if (!cookie)
return -ENOMEM;
cookie->msi_iova = base;
domain->iova_cookie = cookie;
return 0;
}
EXPORT_SYMBOL(iommu_get_msi_cookie);
/**
* iommu_put_dma_cookie - Release a domain's DMA mapping resources
* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie() or
* iommu_get_msi_cookie()
*
* IOMMU drivers should normally call this from their domain_free callback.
*/
void iommu_put_dma_cookie(struct iommu_domain *domain)
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iommu_dma_msi_page *msi, *tmp;
if (!cookie)
return;
if (cookie->type == IOMMU_DMA_IOVA_COOKIE && cookie->iovad.granule)
put_iova_domain(&cookie->iovad);
list_for_each_entry_safe(msi, tmp, &cookie->msi_page_list, list) {
list_del(&msi->list);
kfree(msi);
}
kfree(cookie);
domain->iova_cookie = NULL;
}
EXPORT_SYMBOL(iommu_put_dma_cookie);
/**
* iommu_dma_get_resv_regions - Reserved region driver helper
* @dev: Device from iommu_get_resv_regions()
* @list: Reserved region list from iommu_get_resv_regions()
*
* IOMMU drivers can use this to implement their .get_resv_regions callback
* for general non-IOMMU-specific reservations. Currently, this covers GICv3
* ITS region reservation on ACPI based ARM platforms that may require HW MSI
* reservation.
*/
void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list)
{
if (!is_of_node(dev_iommu_fwspec_get(dev)->iommu_fwnode))
iort_iommu_msi_get_resv_regions(dev, list);
}
EXPORT_SYMBOL(iommu_dma_get_resv_regions);
static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie,
phys_addr_t start, phys_addr_t end)
{
struct iova_domain *iovad = &cookie->iovad;
struct iommu_dma_msi_page *msi_page;
int i, num_pages;
start -= iova_offset(iovad, start);
num_pages = iova_align(iovad, end - start) >> iova_shift(iovad);
msi_page = kcalloc(num_pages, sizeof(*msi_page), GFP_KERNEL);
if (!msi_page)
return -ENOMEM;
for (i = 0; i < num_pages; i++) {
msi_page[i].phys = start;
msi_page[i].iova = start;
INIT_LIST_HEAD(&msi_page[i].list);
list_add(&msi_page[i].list, &cookie->msi_page_list);
start += iovad->granule;
}
return 0;
}
static int iova_reserve_pci_windows(struct pci_dev *dev,
struct iova_domain *iovad)
{
struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
struct resource_entry *window;
unsigned long lo, hi;
phys_addr_t start = 0, end;
resource_list_for_each_entry(window, &bridge->windows) {
if (resource_type(window->res) != IORESOURCE_MEM)
continue;
lo = iova_pfn(iovad, window->res->start - window->offset);
hi = iova_pfn(iovad, window->res->end - window->offset);
reserve_iova(iovad, lo, hi);
}
/* Get reserved DMA windows from host bridge */
resource_list_for_each_entry(window, &bridge->dma_ranges) {
end = window->res->start - window->offset;
resv_iova:
if (end > start) {
lo = iova_pfn(iovad, start);
hi = iova_pfn(iovad, end);
reserve_iova(iovad, lo, hi);
} else {
/* dma_ranges list should be sorted */
dev_err(&dev->dev, "Failed to reserve IOVA\n");
return -EINVAL;
}
start = window->res->end - window->offset + 1;
/* If window is last entry */
if (window->node.next == &bridge->dma_ranges &&
end != ~(phys_addr_t)0) {
end = ~(phys_addr_t)0;
goto resv_iova;
}
}
return 0;
}
static int iova_reserve_iommu_regions(struct device *dev,
struct iommu_domain *domain)
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = &cookie->iovad;
struct iommu_resv_region *region;
LIST_HEAD(resv_regions);
int ret = 0;
if (dev_is_pci(dev)) {
ret = iova_reserve_pci_windows(to_pci_dev(dev), iovad);
if (ret)
return ret;
}
iommu_get_resv_regions(dev, &resv_regions);
list_for_each_entry(region, &resv_regions, list) {
unsigned long lo, hi;
/* We ARE the software that manages these! */
if (region->type == IOMMU_RESV_SW_MSI)
continue;
lo = iova_pfn(iovad, region->start);
hi = iova_pfn(iovad, region->start + region->length - 1);
reserve_iova(iovad, lo, hi);
if (region->type == IOMMU_RESV_MSI)
ret = cookie_init_hw_msi_region(cookie, region->start,
region->start + region->length);
if (ret)
break;
}
iommu_put_resv_regions(dev, &resv_regions);
return ret;
}
static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad)
{
struct iommu_dma_cookie *cookie;
struct iommu_domain *domain;
cookie = container_of(iovad, struct iommu_dma_cookie, iovad);
domain = cookie->fq_domain;
/*
* The IOMMU driver supporting DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE
* implies that ops->flush_iotlb_all must be non-NULL.
*/
domain->ops->flush_iotlb_all(domain);
}
/**
* iommu_dma_init_domain - Initialise a DMA mapping domain
* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
* @base: IOVA at which the mappable address space starts
* @size: Size of IOVA space
* @dev: Device the domain is being initialised for
*
* @base and @size should be exact multiples of IOMMU page granularity to
* avoid rounding surprises. If necessary, we reserve the page at address 0
* to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but
* any change which could make prior IOVAs invalid will fail.
*/
static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
u64 size, struct device *dev)
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = &cookie->iovad;
unsigned long order, base_pfn;
int attr;
if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE)
return -EINVAL;
/* Use the smallest supported page size for IOVA granularity */
order = __ffs(domain->pgsize_bitmap);
base_pfn = max_t(unsigned long, 1, base >> order);
/* Check the domain allows at least some access to the device... */
if (domain->geometry.force_aperture) {
if (base > domain->geometry.aperture_end ||
base + size <= domain->geometry.aperture_start) {
pr_warn("specified DMA range outside IOMMU capability\n");
return -EFAULT;
}
/* ...then finally give it a kicking to make sure it fits */
base_pfn = max_t(unsigned long, base_pfn,
domain->geometry.aperture_start >> order);
}
/* start_pfn is always nonzero for an already-initialised domain */
if (iovad->start_pfn) {
if (1UL << order != iovad->granule ||
base_pfn != iovad->start_pfn) {
pr_warn("Incompatible range for DMA domain\n");
return -EFAULT;
}
return 0;
}
init_iova_domain(iovad, 1UL << order, base_pfn);
if (!cookie->fq_domain && !iommu_domain_get_attr(domain,
DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) && attr) {
cookie->fq_domain = domain;
init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, NULL);
}
if (!dev)
return 0;
return iova_reserve_iommu_regions(dev, domain);
}
/**
* dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API
* page flags.
* @dir: Direction of DMA transfer
* @coherent: Is the DMA master cache-coherent?
* @attrs: DMA attributes for the mapping
*
* Return: corresponding IOMMU API page protection flags
*/
static int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
unsigned long attrs)
{
int prot = coherent ? IOMMU_CACHE : 0;
if (attrs & DMA_ATTR_PRIVILEGED)
prot |= IOMMU_PRIV;
switch (dir) {
case DMA_BIDIRECTIONAL:
return prot | IOMMU_READ | IOMMU_WRITE;
case DMA_TO_DEVICE:
return prot | IOMMU_READ;
case DMA_FROM_DEVICE:
return prot | IOMMU_WRITE;
default:
return 0;
}
}
static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
size_t size, dma_addr_t dma_limit, struct device *dev)
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = &cookie->iovad;
unsigned long shift, iova_len, iova = 0;
if (cookie->type == IOMMU_DMA_MSI_COOKIE) {
cookie->msi_iova += size;
return cookie->msi_iova - size;
}
shift = iova_shift(iovad);
iova_len = size >> shift;
/*
* Freeing non-power-of-two-sized allocations back into the IOVA caches
* will come back to bite us badly, so we have to waste a bit of space
* rounding up anything cacheable to make sure that can't happen. The
* order of the unadjusted size will still match upon freeing.
*/
if (iova_len < (1 << (IOVA_RANGE_CACHE_MAX_SIZE - 1)))
iova_len = roundup_pow_of_two(iova_len);
if (dev->bus_dma_mask)
dma_limit &= dev->bus_dma_mask;
if (domain->geometry.force_aperture)
dma_limit = min(dma_limit, domain->geometry.aperture_end);
/* Try to get PCI devices a SAC address */
if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev))
iova = alloc_iova_fast(iovad, iova_len,
DMA_BIT_MASK(32) >> shift, false);
if (!iova)
iova = alloc_iova_fast(iovad, iova_len, dma_limit >> shift,
true);
return (dma_addr_t)iova << shift;
}
static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
dma_addr_t iova, size_t size)
{
struct iova_domain *iovad = &cookie->iovad;
/* The MSI case is only ever cleaning up its most recent allocation */
if (cookie->type == IOMMU_DMA_MSI_COOKIE)
cookie->msi_iova -= size;
else if (cookie->fq_domain) /* non-strict mode */
queue_iova(iovad, iova_pfn(iovad, iova),
size >> iova_shift(iovad), 0);
else
free_iova_fast(iovad, iova_pfn(iovad, iova),
size >> iova_shift(iovad));
}
static void __iommu_dma_unmap(struct device *dev, dma_addr_t dma_addr,
size_t size)
{
struct iommu_domain *domain = iommu_get_dma_domain(dev);
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = &cookie->iovad;
size_t iova_off = iova_offset(iovad, dma_addr);
dma_addr -= iova_off;
size = iova_align(iovad, size + iova_off);
WARN_ON(iommu_unmap_fast(domain, dma_addr, size) != size);
if (!cookie->fq_domain)
iommu_tlb_sync(domain);
iommu_dma_free_iova(cookie, dma_addr, size);
}
static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
size_t size, int prot)
{
struct iommu_domain *domain = iommu_get_dma_domain(dev);
struct iommu_dma_cookie *cookie = domain->iova_cookie;
size_t iova_off = 0;
dma_addr_t iova;
if (cookie->type == IOMMU_DMA_IOVA_COOKIE) {
iova_off = iova_offset(&cookie->iovad, phys);
size = iova_align(&cookie->iovad, size + iova_off);
}
iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
if (!iova)
return DMA_MAPPING_ERROR;
if (iommu_map(domain, iova, phys - iova_off, size, prot)) {
iommu_dma_free_iova(cookie, iova, size);
return DMA_MAPPING_ERROR;
}
return iova + iova_off;
}
static void __iommu_dma_free_pages(struct page **pages, int count)
{
while (count--)
__free_page(pages[count]);
kvfree(pages);
}
static struct page **__iommu_dma_alloc_pages(struct device *dev,
unsigned int count, unsigned long order_mask, gfp_t gfp)
{
struct page **pages;
unsigned int i = 0, nid = dev_to_node(dev);
order_mask &= (2U << MAX_ORDER) - 1;
if (!order_mask)
return NULL;
pages = kvzalloc(count * sizeof(*pages), GFP_KERNEL);
if (!pages)
return NULL;
/* IOMMU can map any pages, so himem can also be used here */
gfp |= __GFP_NOWARN | __GFP_HIGHMEM;
while (count) {
struct page *page = NULL;
unsigned int order_size;
/*
* Higher-order allocations are a convenience rather
* than a necessity, hence using __GFP_NORETRY until
* falling back to minimum-order allocations.
*/
for (order_mask &= (2U << __fls(count)) - 1;
order_mask; order_mask &= ~order_size) {
unsigned int order = __fls(order_mask);
gfp_t alloc_flags = gfp;
order_size = 1U << order;
if (order_mask > order_size)
alloc_flags |= __GFP_NORETRY;
page = alloc_pages_node(nid, alloc_flags, order);
if (!page)
continue;
if (!order)
break;
if (!PageCompound(page)) {
split_page(page, order);
break;
} else if (!split_huge_page(page)) {
break;
}
__free_pages(page, order);
}
if (!page) {
__iommu_dma_free_pages(pages, i);
return NULL;
}
count -= order_size;
while (order_size--)
pages[i++] = page++;
}
return pages;
}
static struct page **__iommu_dma_get_pages(void *cpu_addr)
{
struct vm_struct *area = find_vm_area(cpu_addr);
if (!area || !area->pages)
return NULL;
return area->pages;
}
/**
* iommu_dma_alloc_remap - Allocate and map a buffer contiguous in IOVA space
* @dev: Device to allocate memory for. Must be a real device
* attached to an iommu_dma_domain
* @size: Size of buffer in bytes
* @dma_handle: Out argument for allocated DMA handle
* @gfp: Allocation flags
* @attrs: DMA attributes for this allocation
*
* If @size is less than PAGE_SIZE, then a full CPU page will be allocated,
* but an IOMMU which supports smaller pages might not map the whole thing.
*
* Return: Mapped virtual address, or NULL on failure.
*/
static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
struct iommu_domain *domain = iommu_get_dma_domain(dev);
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = &cookie->iovad;
bool coherent = dev_is_dma_coherent(dev);
int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap;
struct page **pages;
struct sg_table sgt;
dma_addr_t iova;
void *vaddr;
*dma_handle = DMA_MAPPING_ERROR;
min_size = alloc_sizes & -alloc_sizes;
if (min_size < PAGE_SIZE) {
min_size = PAGE_SIZE;
alloc_sizes |= PAGE_SIZE;
} else {
size = ALIGN(size, min_size);
}
if (attrs & DMA_ATTR_ALLOC_SINGLE_PAGES)
alloc_sizes = min_size;
count = PAGE_ALIGN(size) >> PAGE_SHIFT;
pages = __iommu_dma_alloc_pages(dev, count, alloc_sizes >> PAGE_SHIFT,
gfp);
if (!pages)
return NULL;
size = iova_align(iovad, size);
iova = iommu_dma_alloc_iova(domain, size, dev->coherent_dma_mask, dev);
if (!iova)
goto out_free_pages;
if (sg_alloc_table_from_pages(&sgt, pages, count, 0, size, GFP_KERNEL))
goto out_free_iova;
if (!(ioprot & IOMMU_CACHE)) {
struct scatterlist *sg;
int i;
for_each_sg(sgt.sgl, sg, sgt.orig_nents, i)
arch_dma_prep_coherent(sg_page(sg), sg->length);
}
if (iommu_map_sg(domain, iova, sgt.sgl, sgt.orig_nents, ioprot)
< size)
goto out_free_sg;
vaddr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
__builtin_return_address(0));
if (!vaddr)
goto out_unmap;
*dma_handle = iova;
sg_free_table(&sgt);
return vaddr;
out_unmap:
__iommu_dma_unmap(dev, iova, size);
out_free_sg:
sg_free_table(&sgt);
out_free_iova:
iommu_dma_free_iova(cookie, iova, size);
out_free_pages:
__iommu_dma_free_pages(pages, count);
return NULL;
}
/**
* __iommu_dma_mmap - Map a buffer into provided user VMA
* @pages: Array representing buffer from __iommu_dma_alloc()
* @size: Size of buffer in bytes
* @vma: VMA describing requested userspace mapping
*
* Maps the pages of the buffer in @pages into @vma. The caller is responsible
* for verifying the correct size and protection of @vma beforehand.
*/
static int __iommu_dma_mmap(struct page **pages, size_t size,
struct vm_area_struct *vma)
{
return vm_map_pages(vma, pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
}
static void iommu_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
{
phys_addr_t phys;
if (dev_is_dma_coherent(dev))
return;
phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
arch_sync_dma_for_cpu(dev, phys, size, dir);
}
static void iommu_dma_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
{
phys_addr_t phys;
if (dev_is_dma_coherent(dev))
return;
phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
arch_sync_dma_for_device(dev, phys, size, dir);
}
static void iommu_dma_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sgl, int nelems,
enum dma_data_direction dir)
{
struct scatterlist *sg;
int i;
if (dev_is_dma_coherent(dev))
return;
for_each_sg(sgl, sg, nelems, i)
arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
}
static void iommu_dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sgl, int nelems,
enum dma_data_direction dir)
{
struct scatterlist *sg;
int i;
if (dev_is_dma_coherent(dev))
return;
for_each_sg(sgl, sg, nelems, i)
arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
}
static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
phys_addr_t phys = page_to_phys(page) + offset;
bool coherent = dev_is_dma_coherent(dev);
int prot = dma_info_to_prot(dir, coherent, attrs);
dma_addr_t dma_handle;
dma_handle =__iommu_dma_map(dev, phys, size, prot);
if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
dma_handle != DMA_MAPPING_ERROR)
arch_sync_dma_for_device(dev, phys, size, dir);
return dma_handle;
}
static void iommu_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
iommu_dma_sync_single_for_cpu(dev, dma_handle, size, dir);
__iommu_dma_unmap(dev, dma_handle, size);
}
/*
* Prepare a successfully-mapped scatterlist to give back to the caller.
*
* At this point the segments are already laid out by iommu_dma_map_sg() to
* avoid individually crossing any boundaries, so we merely need to check a
* segment's start address to avoid concatenating across one.
*/
static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents,
dma_addr_t dma_addr)
{
struct scatterlist *s, *cur = sg;
unsigned long seg_mask = dma_get_seg_boundary(dev);
unsigned int cur_len = 0, max_len = dma_get_max_seg_size(dev);
int i, count = 0;
for_each_sg(sg, s, nents, i) {
/* Restore this segment's original unaligned fields first */
unsigned int s_iova_off = sg_dma_address(s);
unsigned int s_length = sg_dma_len(s);
unsigned int s_iova_len = s->length;
s->offset += s_iova_off;
s->length = s_length;
sg_dma_address(s) = DMA_MAPPING_ERROR;
sg_dma_len(s) = 0;
/*
* Now fill in the real DMA data. If...
* - there is a valid output segment to append to
* - and this segment starts on an IOVA page boundary
* - but doesn't fall at a segment boundary
* - and wouldn't make the resulting output segment too long
*/
if (cur_len && !s_iova_off && (dma_addr & seg_mask) &&
(cur_len + s_length <= max_len)) {
/* ...then concatenate it with the previous one */
cur_len += s_length;
} else {
/* Otherwise start the next output segment */
if (i > 0)
cur = sg_next(cur);
cur_len = s_length;
count++;
sg_dma_address(cur) = dma_addr + s_iova_off;
}
sg_dma_len(cur) = cur_len;
dma_addr += s_iova_len;
if (s_length + s_iova_off < s_iova_len)
cur_len = 0;
}
return count;
}
/*
* If mapping failed, then just restore the original list,
* but making sure the DMA fields are invalidated.
*/
static void __invalidate_sg(struct scatterlist *sg, int nents)
{
struct scatterlist *s;
int i;
for_each_sg(sg, s, nents, i) {
if (sg_dma_address(s) != DMA_MAPPING_ERROR)
s->offset += sg_dma_address(s);
if (sg_dma_len(s))
s->length = sg_dma_len(s);
sg_dma_address(s) = DMA_MAPPING_ERROR;
sg_dma_len(s) = 0;
}
}
/*
* The DMA API client is passing in a scatterlist which could describe
* any old buffer layout, but the IOMMU API requires everything to be
* aligned to IOMMU pages. Hence the need for this complicated bit of
* impedance-matching, to be able to hand off a suitably-aligned list,
* but still preserve the original offsets and sizes for the caller.
*/
static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
struct iommu_domain *domain = iommu_get_dma_domain(dev);
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = &cookie->iovad;
struct scatterlist *s, *prev = NULL;
int prot = dma_info_to_prot(dir, dev_is_dma_coherent(dev), attrs);
dma_addr_t iova;
size_t iova_len = 0;
unsigned long mask = dma_get_seg_boundary(dev);
int i;
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
iommu_dma_sync_sg_for_device(dev, sg, nents, dir);
/*
* Work out how much IOVA space we need, and align the segments to
* IOVA granules for the IOMMU driver to handle. With some clever
* trickery we can modify the list in-place, but reversibly, by
* stashing the unaligned parts in the as-yet-unused DMA fields.
*/
for_each_sg(sg, s, nents, i) {
size_t s_iova_off = iova_offset(iovad, s->offset);
size_t s_length = s->length;
size_t pad_len = (mask - iova_len + 1) & mask;
sg_dma_address(s) = s_iova_off;
sg_dma_len(s) = s_length;
s->offset -= s_iova_off;
s_length = iova_align(iovad, s_length + s_iova_off);
s->length = s_length;
/*
* Due to the alignment of our single IOVA allocation, we can
* depend on these assumptions about the segment boundary mask:
* - If mask size >= IOVA size, then the IOVA range cannot
* possibly fall across a boundary, so we don't care.
* - If mask size < IOVA size, then the IOVA range must start
* exactly on a boundary, therefore we can lay things out
* based purely on segment lengths without needing to know
* the actual addresses beforehand.
* - The mask must be a power of 2, so pad_len == 0 if
* iova_len == 0, thus we cannot dereference prev the first
* time through here (i.e. before it has a meaningful value).
*/
if (pad_len && pad_len < s_length - 1) {
prev->length += pad_len;
iova_len += pad_len;
}
iova_len += s_length;
prev = s;
}
iova = iommu_dma_alloc_iova(domain, iova_len, dma_get_mask(dev), dev);
if (!iova)
goto out_restore_sg;
/*
* We'll leave any physical concatenation to the IOMMU driver's
* implementation - it knows better than we do.
*/
if (iommu_map_sg(domain, iova, sg, nents, prot) < iova_len)
goto out_free_iova;
return __finalise_sg(dev, sg, nents, iova);
out_free_iova:
iommu_dma_free_iova(cookie, iova, iova_len);
out_restore_sg:
__invalidate_sg(sg, nents);
return 0;
}
static void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
dma_addr_t start, end;
struct scatterlist *tmp;
int i;
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
iommu_dma_sync_sg_for_cpu(dev, sg, nents, dir);
/*
* The scatterlist segments are mapped into a single
* contiguous IOVA allocation, so this is incredibly easy.
*/
start = sg_dma_address(sg);
for_each_sg(sg_next(sg), tmp, nents - 1, i) {
if (sg_dma_len(tmp) == 0)
break;
sg = tmp;
}
end = sg_dma_address(sg) + sg_dma_len(sg);
__iommu_dma_unmap(dev, start, end - start);
}
static dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
return __iommu_dma_map(dev, phys, size,
dma_info_to_prot(dir, false, attrs) | IOMMU_MMIO);
}
static void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
__iommu_dma_unmap(dev, handle, size);
}
static void __iommu_dma_free(struct device *dev, size_t size, void *cpu_addr)
{
size_t alloc_size = PAGE_ALIGN(size);
int count = alloc_size >> PAGE_SHIFT;
struct page *page = NULL, **pages = NULL;
/* Non-coherent atomic allocation? Easy */
if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
dma_free_from_pool(cpu_addr, alloc_size))
return;
if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {
/*
* If it the address is remapped, then it's either non-coherent
* or highmem CMA, or an iommu_dma_alloc_remap() construction.
*/
pages = __iommu_dma_get_pages(cpu_addr);
if (!pages)
page = vmalloc_to_page(cpu_addr);
dma_common_free_remap(cpu_addr, alloc_size, VM_USERMAP);
} else {
/* Lowmem means a coherent atomic or CMA allocation */
page = virt_to_page(cpu_addr);
}
if (pages)
__iommu_dma_free_pages(pages, count);
if (page)
dma_free_contiguous(dev, page, alloc_size);
}
static void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t handle, unsigned long attrs)
{
__iommu_dma_unmap(dev, handle, size);
__iommu_dma_free(dev, size, cpu_addr);
}
static void *iommu_dma_alloc_pages(struct device *dev, size_t size,
struct page **pagep, gfp_t gfp, unsigned long attrs)
{
bool coherent = dev_is_dma_coherent(dev);
size_t alloc_size = PAGE_ALIGN(size);
struct page *page = NULL;
void *cpu_addr;
page = dma_alloc_contiguous(dev, alloc_size, gfp);
if (!page)
return NULL;
if (IS_ENABLED(CONFIG_DMA_REMAP) && (!coherent || PageHighMem(page))) {
pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
cpu_addr = dma_common_contiguous_remap(page, alloc_size,
VM_USERMAP, prot, __builtin_return_address(0));
if (!cpu_addr)
goto out_free_pages;
if (!coherent)
arch_dma_prep_coherent(page, size);
} else {
cpu_addr = page_address(page);
}
*pagep = page;
memset(cpu_addr, 0, alloc_size);
return cpu_addr;
out_free_pages:
dma_free_contiguous(dev, page, alloc_size);
return NULL;
}
static void *iommu_dma_alloc(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
{
bool coherent = dev_is_dma_coherent(dev);
int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
struct page *page = NULL;
void *cpu_addr;
gfp |= __GFP_ZERO;
if (IS_ENABLED(CONFIG_DMA_REMAP) && gfpflags_allow_blocking(gfp) &&
!(attrs & DMA_ATTR_FORCE_CONTIGUOUS))
return iommu_dma_alloc_remap(dev, size, handle, gfp, attrs);
if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
!gfpflags_allow_blocking(gfp) && !coherent)
cpu_addr = dma_alloc_from_pool(PAGE_ALIGN(size), &page, gfp);
else
cpu_addr = iommu_dma_alloc_pages(dev, size, &page, gfp, attrs);
if (!cpu_addr)
return NULL;
*handle = __iommu_dma_map(dev, page_to_phys(page), size, ioprot);
if (*handle == DMA_MAPPING_ERROR) {
__iommu_dma_free(dev, size, cpu_addr);
return NULL;
}
return cpu_addr;
}
static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long pfn, off = vma->vm_pgoff;
int ret;
vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
return ret;
if (off >= nr_pages || vma_pages(vma) > nr_pages - off)
return -ENXIO;
if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {
struct page **pages = __iommu_dma_get_pages(cpu_addr);
if (pages)
return __iommu_dma_mmap(pages, size, vma);
pfn = vmalloc_to_pfn(cpu_addr);
} else {
pfn = page_to_pfn(virt_to_page(cpu_addr));
}
return remap_pfn_range(vma, vma->vm_start, pfn + off,
vma->vm_end - vma->vm_start,
vma->vm_page_prot);
}
static int iommu_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
struct page *page;
int ret;
if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr)) {
struct page **pages = __iommu_dma_get_pages(cpu_addr);
if (pages) {
return sg_alloc_table_from_pages(sgt, pages,
PAGE_ALIGN(size) >> PAGE_SHIFT,
0, size, GFP_KERNEL);
}
page = vmalloc_to_page(cpu_addr);
} else {
page = virt_to_page(cpu_addr);
}
ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
if (!ret)
sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
return ret;
}
static const struct dma_map_ops iommu_dma_ops = {
.alloc = iommu_dma_alloc,
.free = iommu_dma_free,
.mmap = iommu_dma_mmap,
.get_sgtable = iommu_dma_get_sgtable,
.map_page = iommu_dma_map_page,
.unmap_page = iommu_dma_unmap_page,
.map_sg = iommu_dma_map_sg,
.unmap_sg = iommu_dma_unmap_sg,
.sync_single_for_cpu = iommu_dma_sync_single_for_cpu,
.sync_single_for_device = iommu_dma_sync_single_for_device,
.sync_sg_for_cpu = iommu_dma_sync_sg_for_cpu,
.sync_sg_for_device = iommu_dma_sync_sg_for_device,
.map_resource = iommu_dma_map_resource,
.unmap_resource = iommu_dma_unmap_resource,
};
/*
* The IOMMU core code allocates the default DMA domain, which the underlying
* IOMMU driver needs to support via the dma-iommu layer.
*/
void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size)
{
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
if (!domain)
goto out_err;
/*
* The IOMMU core code allocates the default DMA domain, which the
* underlying IOMMU driver needs to support via the dma-iommu layer.
*/
if (domain->type == IOMMU_DOMAIN_DMA) {
if (iommu_dma_init_domain(domain, dma_base, size, dev))
goto out_err;
dev->dma_ops = &iommu_dma_ops;
}
return;
out_err:
pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
dev_name(dev));
}
static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
phys_addr_t msi_addr, struct iommu_domain *domain)
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iommu_dma_msi_page *msi_page;
dma_addr_t iova;
int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
size_t size = cookie_msi_granule(cookie);
msi_addr &= ~(phys_addr_t)(size - 1);
list_for_each_entry(msi_page, &cookie->msi_page_list, list)
if (msi_page->phys == msi_addr)
return msi_page;
msi_page = kzalloc(sizeof(*msi_page), GFP_ATOMIC);
if (!msi_page)
return NULL;
iova = __iommu_dma_map(dev, msi_addr, size, prot);
if (iova == DMA_MAPPING_ERROR)
goto out_free_page;
INIT_LIST_HEAD(&msi_page->list);
msi_page->phys = msi_addr;
msi_page->iova = iova;
list_add(&msi_page->list, &cookie->msi_page_list);
return msi_page;
out_free_page:
kfree(msi_page);
return NULL;
}
int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
{
struct device *dev = msi_desc_to_dev(desc);
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
struct iommu_dma_cookie *cookie;
struct iommu_dma_msi_page *msi_page;
unsigned long flags;
if (!domain || !domain->iova_cookie) {
desc->iommu_cookie = NULL;
return 0;
}
cookie = domain->iova_cookie;
/*
* We disable IRQs to rule out a possible inversion against
* irq_desc_lock if, say, someone tries to retarget the affinity
* of an MSI from within an IPI handler.
*/
spin_lock_irqsave(&cookie->msi_lock, flags);
msi_page = iommu_dma_get_msi_page(dev, msi_addr, domain);
spin_unlock_irqrestore(&cookie->msi_lock, flags);
msi_desc_set_iommu_cookie(desc, msi_page);
if (!msi_page)
return -ENOMEM;
return 0;
}
void iommu_dma_compose_msi_msg(struct msi_desc *desc,
struct msi_msg *msg)
{
struct device *dev = msi_desc_to_dev(desc);
const struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
const struct iommu_dma_msi_page *msi_page;
msi_page = msi_desc_get_iommu_cookie(desc);
if (!domain || !domain->iova_cookie || WARN_ON(!msi_page))
return;
msg->address_hi = upper_32_bits(msi_page->iova);
msg->address_lo &= cookie_msi_granule(domain->iova_cookie) - 1;
msg->address_lo += lower_32_bits(msi_page->iova);
}
static int iommu_dma_init(void)
{
return iova_cache_get();
}
arch_initcall(iommu_dma_init);