From 5d0b80585e7930e138d6b7781c0f768970e0ffe5 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Fri, 12 Oct 2012 15:23:05 +1100 Subject: [PATCH] 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 Reviewed-by: Konrad Rzeszutek Wilk Signed-off-by: Andrew Morton --- Documentation/DMA-API.txt | 12 +++++ arch/x86/include/asm/dma-mapping.h | 1 + include/linux/dma-debug.h | 7 +++ lib/dma-debug.c | 71 ++++++++++++++++++++++++++++-- 4 files changed, 87 insertions(+), 4 deletions(-) diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index 66bd97a95f10..78a6c569d204 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -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=' 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. + diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h index f7b4c7903e7e..808dae63eeea 100644 --- a/arch/x86/include/asm/dma-mapping.h +++ b/arch/x86/include/asm/dma-mapping.h @@ -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); diff --git a/include/linux/dma-debug.h b/include/linux/dma-debug.h index 171ad8aedc83..fc0e34ce038f 100644 --- a/include/linux/dma-debug.h +++ b/include/linux/dma-debug.h @@ -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) diff --git a/lib/dma-debug.c b/lib/dma-debug.c index b9087bff008b..94aa94effa72 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -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) { -- 2.39.5