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dma-debug: New interfaces to debug dma mapping errors 

Add dma-debug interface debug_dma_mapping_error() to debug
drivers that fail to check dma mapping errors on addresses
returned by dma_map_single() and dma_map_page() interfaces.
This interface clears a flag set by debug_dma_map_page() to
indicate that dma_mapping_error() has been called by the
driver. When driver does unmap, debug_dma_unmap() checks the
flag and if this flag is still set, prints warning message
that includes call trace that leads up to the unmap. This
interface can be called from dma_mapping_error() routines to
enable dma mapping error check debugging.

Tested: Intel iommu and swiotlb (iommu=soft) on x86-64 with
        CONFIG_DMA_API_DEBUG enabled and disabled.

Signed-off-by: Shuah Khan <shuah.khan@hp.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Shuah Khan 2012-10-08 11:08:06 -06:00 committed by Joerg Roedel
parent 6f0c0580b7
commit 6c9c6d6301
4 changed files with 87 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
Documentation/DMA-API.txt
View File

@ -678,3 +678,15 @@ out of dma_debug_entries. These entries are preallocated at boot. The number
of preallocated entries is defined per architecture. If it is too low for you
boot with 'dma_debug_entries=<your_desired_number>' to overwrite the
architectural default.
void debug_dmap_mapping_error(struct device *dev, dma_addr_t dma_addr);
dma-debug interface debug_dma_mapping_error() to debug drivers that fail
to check dma mapping errors on addresses returned by dma_map_single() and
dma_map_page() interfaces. This interface clears a flag set by
debug_dma_map_page() to indicate that dma_mapping_error() has been called by
the driver. When driver does unmap, debug_dma_unmap() checks the flag and if
this flag is still set, prints warning message that includes call trace that
leads up to the unmap. This interface can be called from dma_mapping_error()
routines to enable dma mapping error check debugging.

1
arch/x86/include/asm/dma-mapping.h
View File

@ -47,6 +47,7 @@ static inline struct dma_map_ops *get_dma_ops(struct device *dev)
static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
struct dma_map_ops *ops = get_dma_ops(dev);
debug_dma_mapping_error(dev, dma_addr);
if (ops->mapping_error)
return ops->mapping_error(dev, dma_addr);

7
include/linux/dma-debug.h
View File

@ -39,6 +39,8 @@ extern void debug_dma_map_page(struct device *dev, struct page *page,
int direction, dma_addr_t dma_addr,
bool map_single);
extern void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr);
extern void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, int direction, bool map_single);
@ -105,6 +107,11 @@ static inline void debug_dma_map_page(struct device *dev, struct page *page,
{
}
static inline void debug_dma_mapping_error(struct device *dev,
dma_addr_t dma_addr)
{
}
static inline void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, int direction,
bool map_single)

71
lib/dma-debug.c
View File

@ -45,6 +45,12 @@ enum {
dma_debug_coherent,
};
enum map_err_types {
MAP_ERR_CHECK_NOT_APPLICABLE,
MAP_ERR_NOT_CHECKED,
MAP_ERR_CHECKED,
};
#define DMA_DEBUG_STACKTRACE_ENTRIES 5
struct dma_debug_entry {
@ -57,6 +63,7 @@ struct dma_debug_entry {
int direction;
int sg_call_ents;
int sg_mapped_ents;
enum map_err_types map_err_type;
#ifdef CONFIG_STACKTRACE
struct stack_trace stacktrace;
unsigned long st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
@ -114,6 +121,12 @@ static struct device_driver *current_driver __read_mostly;
static DEFINE_RWLOCK(driver_name_lock);
static const char *const maperr2str[] = {
[MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
[MAP_ERR_NOT_CHECKED] = "dma map error not checked",
[MAP_ERR_CHECKED] = "dma map error checked",
};
static const char *type2name[4] = { "single", "page",
"scather-gather", "coherent" };
@ -376,11 +389,12 @@ void debug_dma_dump_mappings(struct device *dev)
list_for_each_entry(entry, &bucket->list, list) {
if (!dev || dev == entry->dev) {
dev_info(entry->dev,
"%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
"%s idx %d P=%Lx D=%Lx L=%Lx %s %s\n",
type2name[entry->type], idx,
(unsigned long long)entry->paddr,
entry->dev_addr, entry->size,
dir2name[entry->direction]);
dir2name[entry->direction],
maperr2str[entry->map_err_type]);
}
}
@ -838,13 +852,28 @@ static __init int dma_debug_entries_cmdline(char *str)
__setup("dma_debug=", dma_debug_cmdline);
__setup("dma_debug_entries=", dma_debug_entries_cmdline);
/* Calling dma_mapping_error() from dma-debug api will result in calling
debug_dma_mapping_error() - need internal mapping error routine to
avoid debug checks */
#ifndef DMA_ERROR_CODE
#define DMA_ERROR_CODE 0
#endif
static inline int has_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
if (ops->mapping_error)
return ops->mapping_error(dev, dma_addr);
return (dma_addr == DMA_ERROR_CODE);
}
static void check_unmap(struct dma_debug_entry *ref)
{
struct dma_debug_entry *entry;
struct hash_bucket *bucket;
unsigned long flags;
if (dma_mapping_error(ref->dev, ref->dev_addr)) {
if (unlikely(has_mapping_error(ref->dev, ref->dev_addr))) {
err_printk(ref->dev, NULL, "DMA-API: device driver tries "
"to free an invalid DMA memory address\n");
return;
@ -910,6 +939,15 @@ static void check_unmap(struct dma_debug_entry *ref)
dir2name[ref->direction]);
}
if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
err_printk(ref->dev, entry,
"DMA-API: device driver failed to check map error"
"[device address=0x%016llx] [size=%llu bytes] "
"[mapped as %s]",
ref->dev_addr, ref->size,
type2name[entry->type]);
}
hash_bucket_del(entry);
dma_entry_free(entry);
@ -1017,7 +1055,7 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
if (unlikely(global_disable))
return;
if (unlikely(dma_mapping_error(dev, dma_addr)))
if (unlikely(has_mapping_error(dev, dma_addr)))
return;
entry = dma_entry_alloc();
@ -1030,6 +1068,7 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
entry->dev_addr = dma_addr;
entry->size = size;
entry->direction = direction;
entry->map_err_type = MAP_ERR_NOT_CHECKED;
if (map_single)
entry->type = dma_debug_single;
@ -1045,6 +1084,30 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
}
EXPORT_SYMBOL(debug_dma_map_page);
void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
struct dma_debug_entry ref;
struct dma_debug_entry *entry;
struct hash_bucket *bucket;
unsigned long flags;
if (unlikely(global_disable))
return;
ref.dev = dev;
ref.dev_addr = dma_addr;
bucket = get_hash_bucket(&ref, &flags);
entry = bucket_find_exact(bucket, &ref);
if (!entry)
goto out;
entry->map_err_type = MAP_ERR_CHECKED;
out:
put_hash_bucket(bucket, &flags);
}
EXPORT_SYMBOL(debug_dma_mapping_error);
void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, int direction, bool map_single)
{