diff options
| -rw-r--r-- | lib/dma-debug.c | 131 |
1 files changed, 85 insertions, 46 deletions
diff --git a/lib/dma-debug.c b/lib/dma-debug.c index 2defd1308b04..98f2d7e91a91 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -424,111 +424,134 @@ void debug_dma_dump_mappings(struct device *dev) EXPORT_SYMBOL(debug_dma_dump_mappings); /* - * For each page mapped (initial page in the case of - * dma_alloc_coherent/dma_map_{single|page}, or each page in a - * scatterlist) insert into this tree using the pfn as the key. At + * For each mapping (initial cacheline in the case of + * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a + * scatterlist, or the cacheline specified in dma_map_single) insert + * into this tree using the cacheline as the key. At * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry. If - * the pfn already exists at insertion time add a tag as a reference + * the entry already exists at insertion time add a tag as a reference * count for the overlapping mappings. For now, the overlap tracking - * just ensures that 'unmaps' balance 'maps' before marking the pfn - * idle, but we should also be flagging overlaps as an API violation. + * just ensures that 'unmaps' balance 'maps' before marking the + * cacheline idle, but we should also be flagging overlaps as an API + * violation. * * Memory usage is mostly constrained by the maximum number of available * dma-debug entries in that we need a free dma_debug_entry before - * inserting into the tree. In the case of dma_map_{single|page} and - * dma_alloc_coherent there is only one dma_debug_entry and one pfn to - * track per event. dma_map_sg(), on the other hand, - * consumes a single dma_debug_entry, but inserts 'nents' entries into - * the tree. + * inserting into the tree. In the case of dma_map_page and + * dma_alloc_coherent there is only one dma_debug_entry and one + * dma_active_cacheline entry to track per event. dma_map_sg(), on the + * other hand, consumes a single dma_debug_entry, but inserts 'nents' + * entries into the tree. * * At any time debug_dma_assert_idle() can be called to trigger a - * warning if the given page is in the active set. + * warning if any cachelines in the given page are in the active set. */ -static RADIX_TREE(dma_active_pfn, GFP_NOWAIT); +static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT); static DEFINE_SPINLOCK(radix_lock); -#define ACTIVE_PFN_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1) +#define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1) +#define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT) +#define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT) -static int active_pfn_read_overlap(unsigned long pfn) +static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry) +{ + return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) + + (entry->offset >> L1_CACHE_SHIFT); +} + +static int active_cacheline_read_overlap(phys_addr_t cln) { int overlap = 0, i; for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--) - if (radix_tree_tag_get(&dma_active_pfn, pfn, i)) + if (radix_tree_tag_get(&dma_active_cacheline, cln, i)) overlap |= 1 << i; return overlap; } -static int active_pfn_set_overlap(unsigned long pfn, int overlap) +static int active_cacheline_set_overlap(phys_addr_t cln, int overlap) { int i; - if (overlap > ACTIVE_PFN_MAX_OVERLAP || overlap < 0) + if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0) return overlap; for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--) if (overlap & 1 << i) - radix_tree_tag_set(&dma_active_pfn, pfn, i); + radix_tree_tag_set(&dma_active_cacheline, cln, i); else - radix_tree_tag_clear(&dma_active_pfn, pfn, i); + radix_tree_tag_clear(&dma_active_cacheline, cln, i); return overlap; } -static void active_pfn_inc_overlap(unsigned long pfn) +static void active_cacheline_inc_overlap(phys_addr_t cln) { - int overlap = active_pfn_read_overlap(pfn); + int overlap = active_cacheline_read_overlap(cln); - overlap = active_pfn_set_overlap(pfn, ++overlap); + overlap = active_cacheline_set_overlap(cln, ++overlap); /* If we overflowed the overlap counter then we're potentially * leaking dma-mappings. Otherwise, if maps and unmaps are * balanced then this overflow may cause false negatives in - * debug_dma_assert_idle() as the pfn may be marked idle + * debug_dma_assert_idle() as the cacheline may be marked idle * prematurely. */ - WARN_ONCE(overlap > ACTIVE_PFN_MAX_OVERLAP, - "DMA-API: exceeded %d overlapping mappings of pfn %lx\n", - ACTIVE_PFN_MAX_OVERLAP, pfn); + WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP, + "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n", + ACTIVE_CACHELINE_MAX_OVERLAP, &cln); } -static int active_pfn_dec_overlap(unsigned long pfn) +static int active_cacheline_dec_overlap(phys_addr_t cln) { - int overlap = active_pfn_read_overlap(pfn); + int overlap = active_cacheline_read_overlap(cln); - return active_pfn_set_overlap(pfn, --overlap); + return active_cacheline_set_overlap(cln, --overlap); } -static int active_pfn_insert(struct dma_debug_entry *entry) +static int active_cacheline_insert(struct dma_debug_entry *entry) { + phys_addr_t cln = to_cacheline_number(entry); unsigned long flags; int rc; + /* If the device is not writing memory then we don't have any + * concerns about the cpu consuming stale data. This mitigates + * legitimate usages of overlapping mappings. + */ + if (entry->direction == DMA_TO_DEVICE) + return 0; + spin_lock_irqsave(&radix_lock, flags); - rc = radix_tree_insert(&dma_active_pfn, entry->pfn, entry); + rc = radix_tree_insert(&dma_active_cacheline, cln, entry); if (rc == -EEXIST) - active_pfn_inc_overlap(entry->pfn); + active_cacheline_inc_overlap(cln); spin_unlock_irqrestore(&radix_lock, flags); return rc; } -static void active_pfn_remove(struct dma_debug_entry *entry) +static void active_cacheline_remove(struct dma_debug_entry *entry) { + phys_addr_t cln = to_cacheline_number(entry); unsigned long flags; + /* ...mirror the insert case */ + if (entry->direction == DMA_TO_DEVICE) + return; + spin_lock_irqsave(&radix_lock, flags); /* since we are counting overlaps the final put of the - * entry->pfn will occur when the overlap count is 0. - * active_pfn_dec_overlap() returns -1 in that case + * cacheline will occur when the overlap count is 0. + * active_cacheline_dec_overlap() returns -1 in that case */ - if (active_pfn_dec_overlap(entry->pfn) < 0) - radix_tree_delete(&dma_active_pfn, entry->pfn); + if (active_cacheline_dec_overlap(cln) < 0) + radix_tree_delete(&dma_active_cacheline, cln); spin_unlock_irqrestore(&radix_lock, flags); } /** * debug_dma_assert_idle() - assert that a page is not undergoing dma - * @page: page to lookup in the dma_active_pfn tree + * @page: page to lookup in the dma_active_cacheline tree * * Place a call to this routine in cases where the cpu touching the page * before the dma completes (page is dma_unmapped) will lead to data @@ -536,22 +559,38 @@ static void active_pfn_remove(struct dma_debug_entry *entry) */ void debug_dma_assert_idle(struct page *page) { + static struct dma_debug_entry *ents[CACHELINES_PER_PAGE]; + struct dma_debug_entry *entry = NULL; + void **results = (void **) &ents; + unsigned int nents, i; unsigned long flags; - struct dma_debug_entry *entry; + phys_addr_t cln; if (!page) return; + cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT; spin_lock_irqsave(&radix_lock, flags); - entry = radix_tree_lookup(&dma_active_pfn, page_to_pfn(page)); + nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln, + CACHELINES_PER_PAGE); + for (i = 0; i < nents; i++) { + phys_addr_t ent_cln = to_cacheline_number(ents[i]); + + if (ent_cln == cln) { + entry = ents[i]; + break; + } else if (ent_cln >= cln + CACHELINES_PER_PAGE) + break; + } spin_unlock_irqrestore(&radix_lock, flags); if (!entry) return; + cln = to_cacheline_number(entry); err_printk(entry->dev, entry, - "DMA-API: cpu touching an active dma mapped page " - "[pfn=0x%lx]\n", entry->pfn); + "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n", + &cln); } /* @@ -568,9 +607,9 @@ static void add_dma_entry(struct dma_debug_entry *entry) hash_bucket_add(bucket, entry); put_hash_bucket(bucket, &flags); - rc = active_pfn_insert(entry); + rc = active_cacheline_insert(entry); if (rc == -ENOMEM) { - pr_err("DMA-API: pfn tracking ENOMEM, dma-debug disabled\n"); + pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n"); global_disable = true; } @@ -631,7 +670,7 @@ static void dma_entry_free(struct dma_debug_entry *entry) { unsigned long flags; - active_pfn_remove(entry); + active_cacheline_remove(entry); /* * add to beginning of the list - this way the entries are |