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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2018 Christoph Hellwig.
*
* DMA operations that map physical memory directly without using an IOMMU.
*/
#include <linux/memblock.h> /* for max_pfn */
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/dma-direct.h>
#include <linux/scatterlist.h>
#include <linux/dma-contiguous.h>
#include <linux/dma-noncoherent.h>
#include <linux/pfn.h>
#include <linux/set_memory.h>
#include <linux/swiotlb.h>
/*
* Most architectures use ZONE_DMA for the first 16 Megabytes, but
* some use it for entirely different regions:
*/
#ifndef ARCH_ZONE_DMA_BITS
#define ARCH_ZONE_DMA_BITS 24
#endif
/*
* For AMD SEV all DMA must be to unencrypted addresses.
*/
static inline bool force_dma_unencrypted(void)
{
return sev_active();
}
static void report_addr(struct device *dev, dma_addr_t dma_addr, size_t size)
{
if (!dev->dma_mask) {
dev_err_once(dev, "DMA map on device without dma_mask\n");
} else if (*dev->dma_mask >= DMA_BIT_MASK(32) || dev->bus_dma_mask) {
dev_err_once(dev,
"overflow %pad+%zu of DMA mask %llx bus mask %llx\n",
&dma_addr, size, *dev->dma_mask, dev->bus_dma_mask);
}
WARN_ON_ONCE(1);
}
static inline dma_addr_t phys_to_dma_direct(struct device *dev,
phys_addr_t phys)
{
if (force_dma_unencrypted())
return __phys_to_dma(dev, phys);
return phys_to_dma(dev, phys);
}
u64 dma_direct_get_required_mask(struct device *dev)
{
u64 max_dma = phys_to_dma_direct(dev, (max_pfn - 1) << PAGE_SHIFT);
if (dev->bus_dma_mask && dev->bus_dma_mask < max_dma)
max_dma = dev->bus_dma_mask;
return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
}
static gfp_t __dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
u64 *phys_mask)
{
if (dev->bus_dma_mask && dev->bus_dma_mask < dma_mask)
dma_mask = dev->bus_dma_mask;
if (force_dma_unencrypted())
*phys_mask = __dma_to_phys(dev, dma_mask);
else
*phys_mask = dma_to_phys(dev, dma_mask);
/*
* Optimistically try the zone that the physical address mask falls
* into first. If that returns memory that isn't actually addressable
* we will fallback to the next lower zone and try again.
*
* Note that GFP_DMA32 and GFP_DMA are no ops without the corresponding
* zones.
*/
if (*phys_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
return GFP_DMA;
if (*phys_mask <= DMA_BIT_MASK(32))
return GFP_DMA32;
return 0;
}
static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
{
return phys_to_dma_direct(dev, phys) + size - 1 <=
min_not_zero(dev->coherent_dma_mask, dev->bus_dma_mask);
}
struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
int page_order = get_order(size);
struct page *page = NULL;
u64 phys_mask;
if (attrs & DMA_ATTR_NO_WARN)
gfp |= __GFP_NOWARN;
/* we always manually zero the memory once we are done: */
gfp &= ~__GFP_ZERO;
gfp |= __dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
&phys_mask);
again:
/* CMA can be used only in the context which permits sleeping */
if (gfpflags_allow_blocking(gfp)) {
page = dma_alloc_from_contiguous(dev, count, page_order,
gfp & __GFP_NOWARN);
if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
dma_release_from_contiguous(dev, page, count);
page = NULL;
}
}
if (!page)
page = alloc_pages_node(dev_to_node(dev), gfp, page_order);
if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
__free_pages(page, page_order);
page = NULL;
if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
phys_mask < DMA_BIT_MASK(64) &&
!(gfp & (GFP_DMA32 | GFP_DMA))) {
gfp |= GFP_DMA32;
goto again;
}
if (IS_ENABLED(CONFIG_ZONE_DMA) && !(gfp & GFP_DMA)) {
gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
goto again;
}
}
return page;
}
void *dma_direct_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
struct page *page;
void *ret;
page = __dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
if (!page)
return NULL;
if (PageHighMem(page)) {
/*
* Depending on the cma= arguments and per-arch setup
* dma_alloc_from_contiguous could return highmem pages.
* Without remapping there is no way to return them here,
* so log an error and fail.
*/
dev_info(dev, "Rejecting highmem page from CMA.\n");
__dma_direct_free_pages(dev, size, page);
return NULL;
}
ret = page_address(page);
if (force_dma_unencrypted()) {
set_memory_decrypted((unsigned long)ret, 1 << get_order(size));
*dma_handle = __phys_to_dma(dev, page_to_phys(page));
} else {
*dma_handle = phys_to_dma(dev, page_to_phys(page));
}
memset(ret, 0, size);
return ret;
}
void __dma_direct_free_pages(struct device *dev, size_t size, struct page *page)
{
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
if (!dma_release_from_contiguous(dev, page, count))
__free_pages(page, get_order(size));
}
void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_addr, unsigned long attrs)
{
unsigned int page_order = get_order(size);
if (force_dma_unencrypted())
set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
__dma_direct_free_pages(dev, size, virt_to_page(cpu_addr));
}
void *dma_direct_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
if (!dev_is_dma_coherent(dev))
return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
return dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs);
}
void dma_direct_free(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
{
if (!dev_is_dma_coherent(dev))
arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
else
dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs);
}
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
defined(CONFIG_SWIOTLB)
void dma_direct_sync_single_for_device(struct device *dev,
dma_addr_t addr, size_t size, enum dma_data_direction dir)
{
phys_addr_t paddr = dma_to_phys(dev, addr);
if (unlikely(is_swiotlb_buffer(paddr)))
swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_DEVICE);
if (!dev_is_dma_coherent(dev))
arch_sync_dma_for_device(dev, paddr, size, dir);
}
EXPORT_SYMBOL(dma_direct_sync_single_for_device);
void dma_direct_sync_sg_for_device(struct device *dev,
struct scatterlist *sgl, int nents, enum dma_data_direction dir)
{
struct scatterlist *sg;
int i;
for_each_sg(sgl, sg, nents, i) {
if (unlikely(is_swiotlb_buffer(sg_phys(sg))))
swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length,
dir, SYNC_FOR_DEVICE);
if (!dev_is_dma_coherent(dev))
arch_sync_dma_for_device(dev, sg_phys(sg), sg->length,
dir);
}
}
EXPORT_SYMBOL(dma_direct_sync_sg_for_device);
#endif
#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) || \
defined(CONFIG_SWIOTLB)
void dma_direct_sync_single_for_cpu(struct device *dev,
dma_addr_t addr, size_t size, enum dma_data_direction dir)
{
phys_addr_t paddr = dma_to_phys(dev, addr);
if (!dev_is_dma_coherent(dev)) {
arch_sync_dma_for_cpu(dev, paddr, size, dir);
arch_sync_dma_for_cpu_all(dev);
}
if (unlikely(is_swiotlb_buffer(paddr)))
swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU);
}
EXPORT_SYMBOL(dma_direct_sync_single_for_cpu);
void dma_direct_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sgl, int nents, enum dma_data_direction dir)
{
struct scatterlist *sg;
int i;
for_each_sg(sgl, sg, nents, i) {
if (!dev_is_dma_coherent(dev))
arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
if (unlikely(is_swiotlb_buffer(sg_phys(sg))))
swiotlb_tbl_sync_single(dev, sg_phys(sg), sg->length, dir,
SYNC_FOR_CPU);
}
if (!dev_is_dma_coherent(dev))
arch_sync_dma_for_cpu_all(dev);
}
EXPORT_SYMBOL(dma_direct_sync_sg_for_cpu);
void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
phys_addr_t phys = dma_to_phys(dev, addr);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_direct_sync_single_for_cpu(dev, addr, size, dir);
if (unlikely(is_swiotlb_buffer(phys)))
swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs);
}
EXPORT_SYMBOL(dma_direct_unmap_page);
void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
struct scatterlist *sg;
int i;
for_each_sg(sgl, sg, nents, i)
dma_direct_unmap_page(dev, sg->dma_address, sg_dma_len(sg), dir,
attrs);
}
EXPORT_SYMBOL(dma_direct_unmap_sg);
#endif
static inline bool dma_direct_possible(struct device *dev, dma_addr_t dma_addr,
size_t size)
{
return swiotlb_force != SWIOTLB_FORCE &&
(!dev || dma_capable(dev, dma_addr, size));
}
dma_addr_t dma_direct_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;
dma_addr_t dma_addr = phys_to_dma(dev, phys);
if (unlikely(!dma_direct_possible(dev, dma_addr, size)) &&
!swiotlb_map(dev, &phys, &dma_addr, size, dir, attrs)) {
report_addr(dev, dma_addr, size);
return DMA_MAPPING_ERROR;
}
if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
arch_sync_dma_for_device(dev, phys, size, dir);
return dma_addr;
}
EXPORT_SYMBOL(dma_direct_map_page);
int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
enum dma_data_direction dir, unsigned long attrs)
{
int i;
struct scatterlist *sg;
for_each_sg(sgl, sg, nents, i) {
sg->dma_address = dma_direct_map_page(dev, sg_page(sg),
sg->offset, sg->length, dir, attrs);
if (sg->dma_address == DMA_MAPPING_ERROR)
goto out_unmap;
sg_dma_len(sg) = sg->length;
}
return nents;
out_unmap:
dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
return 0;
}
EXPORT_SYMBOL(dma_direct_map_sg);
dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
dma_addr_t dma_addr = paddr;
if (unlikely(!dma_direct_possible(dev, dma_addr, size))) {
report_addr(dev, dma_addr, size);
return DMA_MAPPING_ERROR;
}
return dma_addr;
}
EXPORT_SYMBOL(dma_direct_map_resource);
/*
* Because 32-bit DMA masks are so common we expect every architecture to be
* able to satisfy them - either by not supporting more physical memory, or by
* providing a ZONE_DMA32. If neither is the case, the architecture needs to
* use an IOMMU instead of the direct mapping.
*/
int dma_direct_supported(struct device *dev, u64 mask)
{
u64 min_mask;
if (IS_ENABLED(CONFIG_ZONE_DMA))
min_mask = DMA_BIT_MASK(ARCH_ZONE_DMA_BITS);
else
min_mask = DMA_BIT_MASK(32);
min_mask = min_t(u64, min_mask, (max_pfn - 1) << PAGE_SHIFT);
/*
* This check needs to be against the actual bit mask value, so
* use __phys_to_dma() here so that the SME encryption mask isn't
* part of the check.
*/
return mask >= __phys_to_dma(dev, min_mask);
}
size_t dma_direct_max_mapping_size(struct device *dev)
{
size_t size = SIZE_MAX;
/* If SWIOTLB is active, use its maximum mapping size */
if (is_swiotlb_active())
size = swiotlb_max_mapping_size(dev);
return size;
}