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Merge tag 'dma-mapping-5.6' of git://git.infradead.org/users/hch/dma-…
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…mapping

Pull dma-mapping fixes from Christoph Hellwig:

 - give command line cma= precedence over the CONFIG_ option (Nicolas
   Saenz Julienne)

 - always allow 32-bit DMA, even for weirdly placed ZONE_DMA

 - improve the debug printks when memory is not addressable, to help
   find problems with swiotlb initialization

* tag 'dma-mapping-5.6' of git://git.infradead.org/users/hch/dma-mapping:
  dma-direct: improve DMA mask overflow reporting
  dma-direct: improve swiotlb error reporting
  dma-direct: relax addressability checks in dma_direct_supported
  dma-contiguous: CMA: give precedence to cmdline
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torvalds committed Feb 18, 2020
2 parents 2b72104 + 75467ee commit 0a44cac
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Showing 4 changed files with 59 additions and 64 deletions.
11 changes: 3 additions & 8 deletions include/linux/swiotlb.h
Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,9 @@ extern void swiotlb_tbl_sync_single(struct device *hwdev,
size_t size, enum dma_data_direction dir,
enum dma_sync_target target);

dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys,
size_t size, enum dma_data_direction dir, unsigned long attrs);

#ifdef CONFIG_SWIOTLB
extern enum swiotlb_force swiotlb_force;
extern phys_addr_t io_tlb_start, io_tlb_end;
Expand All @@ -73,8 +76,6 @@ static inline bool is_swiotlb_buffer(phys_addr_t paddr)
return paddr >= io_tlb_start && paddr < io_tlb_end;
}

bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
size_t size, enum dma_data_direction dir, unsigned long attrs);
void __init swiotlb_exit(void);
unsigned int swiotlb_max_segment(void);
size_t swiotlb_max_mapping_size(struct device *dev);
Expand All @@ -85,12 +86,6 @@ static inline bool is_swiotlb_buffer(phys_addr_t paddr)
{
return false;
}
static inline bool swiotlb_map(struct device *dev, phys_addr_t *phys,
dma_addr_t *dma_addr, size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
return false;
}
static inline void swiotlb_exit(void)
{
}
Expand Down
9 changes: 8 additions & 1 deletion kernel/dma/contiguous.c
Original file line number Diff line number Diff line change
Expand Up @@ -302,9 +302,16 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
phys_addr_t mask = align - 1;
unsigned long node = rmem->fdt_node;
bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
struct cma *cma;
int err;

if (size_cmdline != -1 && default_cma) {
pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n",
rmem->name);
return -EBUSY;
}

if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
of_get_flat_dt_prop(node, "no-map", NULL))
return -EINVAL;
Expand All @@ -322,7 +329,7 @@ static int __init rmem_cma_setup(struct reserved_mem *rmem)
/* Architecture specific contiguous memory fixup. */
dma_contiguous_early_fixup(rmem->base, rmem->size);

if (of_get_flat_dt_prop(node, "linux,cma-default", NULL))
if (default_cma)
dma_contiguous_set_default(cma);

rmem->ops = &rmem_cma_ops;
Expand Down
61 changes: 25 additions & 36 deletions kernel/dma/direct.c
Original file line number Diff line number Diff line change
Expand Up @@ -23,18 +23,6 @@
*/
unsigned int zone_dma_bits __ro_after_init = 24;

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_limit) {
dev_err_once(dev,
"overflow %pad+%zu of DMA mask %llx bus limit %llx\n",
&dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
}
WARN_ON_ONCE(1);
}

static inline dma_addr_t phys_to_dma_direct(struct device *dev,
phys_addr_t phys)
{
Expand Down Expand Up @@ -357,23 +345,23 @@ void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
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 &&
dma_capable(dev, dma_addr, size, true);
}

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);
if (unlikely(swiotlb_force == SWIOTLB_FORCE))
return swiotlb_map(dev, phys, size, dir, attrs);

if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
if (swiotlb_force != SWIOTLB_NO_FORCE)
return swiotlb_map(dev, phys, size, dir, attrs);

dev_WARN_ONCE(dev, 1,
"DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
&dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
return DMA_MAPPING_ERROR;
}

Expand Down Expand Up @@ -411,7 +399,10 @@ dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
dma_addr_t dma_addr = paddr;

if (unlikely(!dma_capable(dev, dma_addr, size, false))) {
report_addr(dev, dma_addr, size);
dev_err_once(dev,
"DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
&dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
WARN_ON_ONCE(1);
return DMA_MAPPING_ERROR;
}

Expand Down Expand Up @@ -472,28 +463,26 @@ int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
}
#endif /* CONFIG_MMU */

/*
* 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;
u64 min_mask = (max_pfn - 1) << PAGE_SHIFT;

if (IS_ENABLED(CONFIG_ZONE_DMA))
min_mask = DMA_BIT_MASK(zone_dma_bits);
else
min_mask = DMA_BIT_MASK(32);

min_mask = min_t(u64, min_mask, (max_pfn - 1) << PAGE_SHIFT);
/*
* 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.
*/
if (mask >= DMA_BIT_MASK(32))
return 1;

/*
* 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.
*/
if (IS_ENABLED(CONFIG_ZONE_DMA))
min_mask = min_t(u64, min_mask, DMA_BIT_MASK(zone_dma_bits));
return mask >= __phys_to_dma(dev, min_mask);
}

Expand Down
42 changes: 23 additions & 19 deletions kernel/dma/swiotlb.c
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@

#include <linux/cache.h>
#include <linux/dma-direct.h>
#include <linux/dma-noncoherent.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/spinlock.h>
Expand Down Expand Up @@ -656,35 +657,38 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
}

/*
* Create a swiotlb mapping for the buffer at @phys, and in case of DMAing
* Create a swiotlb mapping for the buffer at @paddr, and in case of DMAing
* to the device copy the data into it as well.
*/
bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
enum dma_data_direction dir, unsigned long attrs)
{
trace_swiotlb_bounced(dev, *dma_addr, size, swiotlb_force);
phys_addr_t swiotlb_addr;
dma_addr_t dma_addr;

if (unlikely(swiotlb_force == SWIOTLB_NO_FORCE)) {
dev_warn_ratelimited(dev,
"Cannot do DMA to address %pa\n", phys);
return false;
}
trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size,
swiotlb_force);

/* Oh well, have to allocate and map a bounce buffer. */
*phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start),
*phys, size, size, dir, attrs);
if (*phys == (phys_addr_t)DMA_MAPPING_ERROR)
return false;
swiotlb_addr = swiotlb_tbl_map_single(dev,
__phys_to_dma(dev, io_tlb_start),
paddr, size, size, 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(dev, *phys);
if (unlikely(!dma_capable(dev, *dma_addr, size, true))) {
swiotlb_tbl_unmap_single(dev, *phys, size, size, dir,
dma_addr = __phys_to_dma(dev, swiotlb_addr);
if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, size, dir,
attrs | DMA_ATTR_SKIP_CPU_SYNC);
return false;
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;
}

return true;
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)
Expand Down

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