diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-10 16:19:14 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-10 16:19:14 -0700 |
commit | 3f6280ddf25fa656d0e17960588e52bee48a7547 (patch) | |
tree | 006854e51246e400c248a9722418bc7a7cce2dbf /lib/dma-debug.c | |
parent | 75063600fd7b27fe447112c27997f100b9e2f99b (diff) | |
parent | 92db1e6af747faa129e236d68386af26a0efc12b (diff) |
Merge branch 'iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (61 commits)
amd-iommu: remove unnecessary "AMD IOMMU: " prefix
amd-iommu: detach device explicitly before attaching it to a new domain
amd-iommu: remove BUS_NOTIFY_BOUND_DRIVER handling
dma-debug: simplify logic in driver_filter()
dma-debug: disable/enable irqs only once in device_dma_allocations
dma-debug: use pr_* instead of printk(KERN_* ...)
dma-debug: code style fixes
dma-debug: comment style fixes
dma-debug: change hash_bucket_find from first-fit to best-fit
x86: enable GART-IOMMU only after setting up protection methods
amd_iommu: fix lock imbalance
dma-debug: add documentation for the driver filter
dma-debug: add dma_debug_driver kernel command line
dma-debug: add debugfs file for driver filter
dma-debug: add variables and checks for driver filter
dma-debug: fix debug_dma_sync_sg_for_cpu and debug_dma_sync_sg_for_device
dma-debug: use sg_dma_len accessor
dma-debug: use sg_dma_address accessor instead of using dma_address directly
amd-iommu: don't free dma adresses below 512MB with CONFIG_IOMMU_STRESS
amd-iommu: don't preallocate page tables with CONFIG_IOMMU_STRESS
...
Diffstat (limited to 'lib/dma-debug.c')
-rw-r--r-- | lib/dma-debug.c | 432 |
1 files changed, 387 insertions, 45 deletions
diff --git a/lib/dma-debug.c b/lib/dma-debug.c index 69da09a085a..ad65fc0317d 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -23,9 +23,11 @@ #include <linux/dma-debug.h> #include <linux/spinlock.h> #include <linux/debugfs.h> +#include <linux/uaccess.h> #include <linux/device.h> #include <linux/types.h> #include <linux/sched.h> +#include <linux/ctype.h> #include <linux/list.h> #include <linux/slab.h> @@ -85,6 +87,7 @@ static u32 show_num_errors = 1; static u32 num_free_entries; static u32 min_free_entries; +static u32 nr_total_entries; /* number of preallocated entries requested by kernel cmdline */ static u32 req_entries; @@ -97,6 +100,16 @@ static struct dentry *show_all_errors_dent __read_mostly; static struct dentry *show_num_errors_dent __read_mostly; static struct dentry *num_free_entries_dent __read_mostly; static struct dentry *min_free_entries_dent __read_mostly; +static struct dentry *filter_dent __read_mostly; + +/* per-driver filter related state */ + +#define NAME_MAX_LEN 64 + +static char current_driver_name[NAME_MAX_LEN] __read_mostly; +static struct device_driver *current_driver __read_mostly; + +static DEFINE_RWLOCK(driver_name_lock); static const char *type2name[4] = { "single", "page", "scather-gather", "coherent" }; @@ -104,6 +117,11 @@ static const char *type2name[4] = { "single", "page", static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE", "DMA_FROM_DEVICE", "DMA_NONE" }; +/* little merge helper - remove it after the merge window */ +#ifndef BUS_NOTIFY_UNBOUND_DRIVER +#define BUS_NOTIFY_UNBOUND_DRIVER 0x0005 +#endif + /* * The access to some variables in this macro is racy. We can't use atomic_t * here because all these variables are exported to debugfs. Some of them even @@ -121,15 +139,54 @@ static inline void dump_entry_trace(struct dma_debug_entry *entry) { #ifdef CONFIG_STACKTRACE if (entry) { - printk(KERN_WARNING "Mapped at:\n"); + pr_warning("Mapped at:\n"); print_stack_trace(&entry->stacktrace, 0); } #endif } +static bool driver_filter(struct device *dev) +{ + struct device_driver *drv; + unsigned long flags; + bool ret; + + /* driver filter off */ + if (likely(!current_driver_name[0])) + return true; + + /* driver filter on and initialized */ + if (current_driver && dev->driver == current_driver) + return true; + + if (current_driver || !current_driver_name[0]) + return false; + + /* driver filter on but not yet initialized */ + drv = get_driver(dev->driver); + if (!drv) + return false; + + /* lock to protect against change of current_driver_name */ + read_lock_irqsave(&driver_name_lock, flags); + + ret = false; + if (drv->name && + strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) { + current_driver = drv; + ret = true; + } + + read_unlock_irqrestore(&driver_name_lock, flags); + put_driver(drv); + + return ret; +} + #define err_printk(dev, entry, format, arg...) do { \ error_count += 1; \ - if (show_all_errors || show_num_errors > 0) { \ + if (driver_filter(dev) && \ + (show_all_errors || show_num_errors > 0)) { \ WARN(1, "%s %s: " format, \ dev_driver_string(dev), \ dev_name(dev) , ## arg); \ @@ -185,15 +242,50 @@ static void put_hash_bucket(struct hash_bucket *bucket, static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket, struct dma_debug_entry *ref) { - struct dma_debug_entry *entry; + struct dma_debug_entry *entry, *ret = NULL; + int matches = 0, match_lvl, last_lvl = 0; list_for_each_entry(entry, &bucket->list, list) { - if ((entry->dev_addr == ref->dev_addr) && - (entry->dev == ref->dev)) + if ((entry->dev_addr != ref->dev_addr) || + (entry->dev != ref->dev)) + continue; + + /* + * Some drivers map the same physical address multiple + * times. Without a hardware IOMMU this results in the + * same device addresses being put into the dma-debug + * hash multiple times too. This can result in false + * positives being reported. Therfore we implement a + * best-fit algorithm here which returns the entry from + * the hash which fits best to the reference value + * instead of the first-fit. + */ + matches += 1; + match_lvl = 0; + entry->size == ref->size ? ++match_lvl : match_lvl; + entry->type == ref->type ? ++match_lvl : match_lvl; + entry->direction == ref->direction ? ++match_lvl : match_lvl; + + if (match_lvl == 3) { + /* perfect-fit - return the result */ return entry; + } else if (match_lvl > last_lvl) { + /* + * We found an entry that fits better then the + * previous one + */ + last_lvl = match_lvl; + ret = entry; + } } - return NULL; + /* + * If we have multiple matches but no perfect-fit, just return + * NULL. + */ + ret = (matches == 1) ? ret : NULL; + + return ret; } /* @@ -257,6 +349,21 @@ static void add_dma_entry(struct dma_debug_entry *entry) put_hash_bucket(bucket, &flags); } +static struct dma_debug_entry *__dma_entry_alloc(void) +{ + struct dma_debug_entry *entry; + + entry = list_entry(free_entries.next, struct dma_debug_entry, list); + list_del(&entry->list); + memset(entry, 0, sizeof(*entry)); + + num_free_entries -= 1; + if (num_free_entries < min_free_entries) + min_free_entries = num_free_entries; + + return entry; +} + /* struct dma_entry allocator * * The next two functions implement the allocator for @@ -270,15 +377,12 @@ static struct dma_debug_entry *dma_entry_alloc(void) spin_lock_irqsave(&free_entries_lock, flags); if (list_empty(&free_entries)) { - printk(KERN_ERR "DMA-API: debugging out of memory " - "- disabling\n"); + pr_err("DMA-API: debugging out of memory - disabling\n"); global_disable = true; goto out; } - entry = list_entry(free_entries.next, struct dma_debug_entry, list); - list_del(&entry->list); - memset(entry, 0, sizeof(*entry)); + entry = __dma_entry_alloc(); #ifdef CONFIG_STACKTRACE entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES; @@ -286,9 +390,6 @@ static struct dma_debug_entry *dma_entry_alloc(void) entry->stacktrace.skip = 2; save_stack_trace(&entry->stacktrace); #endif - num_free_entries -= 1; - if (num_free_entries < min_free_entries) - min_free_entries = num_free_entries; out: spin_unlock_irqrestore(&free_entries_lock, flags); @@ -310,6 +411,53 @@ static void dma_entry_free(struct dma_debug_entry *entry) spin_unlock_irqrestore(&free_entries_lock, flags); } +int dma_debug_resize_entries(u32 num_entries) +{ + int i, delta, ret = 0; + unsigned long flags; + struct dma_debug_entry *entry; + LIST_HEAD(tmp); + + spin_lock_irqsave(&free_entries_lock, flags); + + if (nr_total_entries < num_entries) { + delta = num_entries - nr_total_entries; + + spin_unlock_irqrestore(&free_entries_lock, flags); + + for (i = 0; i < delta; i++) { + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + break; + + list_add_tail(&entry->list, &tmp); + } + + spin_lock_irqsave(&free_entries_lock, flags); + + list_splice(&tmp, &free_entries); + nr_total_entries += i; + num_free_entries += i; + } else { + delta = nr_total_entries - num_entries; + + for (i = 0; i < delta && !list_empty(&free_entries); i++) { + entry = __dma_entry_alloc(); + kfree(entry); + } + + nr_total_entries -= i; + } + + if (nr_total_entries != num_entries) + ret = 1; + + spin_unlock_irqrestore(&free_entries_lock, flags); + + return ret; +} +EXPORT_SYMBOL(dma_debug_resize_entries); + /* * DMA-API debugging init code * @@ -334,8 +482,7 @@ static int prealloc_memory(u32 num_entries) num_free_entries = num_entries; min_free_entries = num_entries; - printk(KERN_INFO "DMA-API: preallocated %d debug entries\n", - num_entries); + pr_info("DMA-API: preallocated %d debug entries\n", num_entries); return 0; @@ -349,11 +496,102 @@ out_err: return -ENOMEM; } +static ssize_t filter_read(struct file *file, char __user *user_buf, + size_t count, loff_t *ppos) +{ + char buf[NAME_MAX_LEN + 1]; + unsigned long flags; + int len; + + if (!current_driver_name[0]) + return 0; + + /* + * We can't copy to userspace directly because current_driver_name can + * only be read under the driver_name_lock with irqs disabled. So + * create a temporary copy first. + */ + read_lock_irqsave(&driver_name_lock, flags); + len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name); + read_unlock_irqrestore(&driver_name_lock, flags); + + return simple_read_from_buffer(user_buf, count, ppos, buf, len); +} + +static ssize_t filter_write(struct file *file, const char __user *userbuf, + size_t count, loff_t *ppos) +{ + char buf[NAME_MAX_LEN]; + unsigned long flags; + size_t len; + int i; + + /* + * We can't copy from userspace directly. Access to + * current_driver_name is protected with a write_lock with irqs + * disabled. Since copy_from_user can fault and may sleep we + * need to copy to temporary buffer first + */ + len = min(count, (size_t)(NAME_MAX_LEN - 1)); + if (copy_from_user(buf, userbuf, len)) + return -EFAULT; + + buf[len] = 0; + + write_lock_irqsave(&driver_name_lock, flags); + + /* + * Now handle the string we got from userspace very carefully. + * The rules are: + * - only use the first token we got + * - token delimiter is everything looking like a space + * character (' ', '\n', '\t' ...) + * + */ + if (!isalnum(buf[0])) { + /* + * If the first character userspace gave us is not + * alphanumerical then assume the filter should be + * switched off. + */ + if (current_driver_name[0]) + pr_info("DMA-API: switching off dma-debug driver filter\n"); + current_driver_name[0] = 0; + current_driver = NULL; + goto out_unlock; + } + + /* + * Now parse out the first token and use it as the name for the + * driver to filter for. + */ + for (i = 0; i < NAME_MAX_LEN; ++i) { + current_driver_name[i] = buf[i]; + if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0) + break; + } + current_driver_name[i] = 0; + current_driver = NULL; + + pr_info("DMA-API: enable driver filter for driver [%s]\n", + current_driver_name); + +out_unlock: + write_unlock_irqrestore(&driver_name_lock, flags); + + return count; +} + +const struct file_operations filter_fops = { + .read = filter_read, + .write = filter_write, +}; + static int dma_debug_fs_init(void) { dma_debug_dent = debugfs_create_dir("dma-api", NULL); if (!dma_debug_dent) { - printk(KERN_ERR "DMA-API: can not create debugfs directory\n"); + pr_err("DMA-API: can not create debugfs directory\n"); return -ENOMEM; } @@ -392,6 +630,11 @@ static int dma_debug_fs_init(void) if (!min_free_entries_dent) goto out_err; + filter_dent = debugfs_create_file("driver_filter", 0644, + dma_debug_dent, NULL, &filter_fops); + if (!filter_dent) + goto out_err; + return 0; out_err: @@ -400,9 +643,64 @@ out_err: return -ENOMEM; } +static int device_dma_allocations(struct device *dev) +{ + struct dma_debug_entry *entry; + unsigned long flags; + int count = 0, i; + + local_irq_save(flags); + + for (i = 0; i < HASH_SIZE; ++i) { + spin_lock(&dma_entry_hash[i].lock); + list_for_each_entry(entry, &dma_entry_hash[i].list, list) { + if (entry->dev == dev) + count += 1; + } + spin_unlock(&dma_entry_hash[i].lock); + } + + local_irq_restore(flags); + + return count; +} + +static int dma_debug_device_change(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct device *dev = data; + int count; + + + switch (action) { + case BUS_NOTIFY_UNBOUND_DRIVER: + count = device_dma_allocations(dev); + if (count == 0) + break; + err_printk(dev, NULL, "DMA-API: device driver has pending " + "DMA allocations while released from device " + "[count=%d]\n", count); + break; + default: + break; + } + + return 0; +} + void dma_debug_add_bus(struct bus_type *bus) { - /* FIXME: register notifier */ + struct notifier_block *nb; + + nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL); + if (nb == NULL) { + pr_err("dma_debug_add_bus: out of memory\n"); + return; + } + + nb->notifier_call = dma_debug_device_change; + + bus_register_notifier(bus, nb); } /* @@ -421,8 +719,7 @@ void dma_debug_init(u32 num_entries) } if (dma_debug_fs_init() != 0) { - printk(KERN_ERR "DMA-API: error creating debugfs entries " - "- disabling\n"); + pr_err("DMA-API: error creating debugfs entries - disabling\n"); global_disable = true; return; @@ -432,14 +729,15 @@ void dma_debug_init(u32 num_entries) num_entries = req_entries; if (prealloc_memory(num_entries) != 0) { - printk(KERN_ERR "DMA-API: debugging out of memory error " - "- disabled\n"); + pr_err("DMA-API: debugging out of memory error - disabled\n"); global_disable = true; return; } - printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n"); + nr_total_entries = num_free_entries; + + pr_info("DMA-API: debugging enabled by kernel config\n"); } static __init int dma_debug_cmdline(char *str) @@ -448,8 +746,7 @@ static __init int dma_debug_cmdline(char *str) return -EINVAL; if (strncmp(str, "off", 3) == 0) { - printk(KERN_INFO "DMA-API: debugging disabled on kernel " - "command line\n"); + pr_info("DMA-API: debugging disabled on kernel command line\n"); global_disable = true; } @@ -723,15 +1020,15 @@ void debug_dma_map_sg(struct device *dev, struct scatterlist *sg, entry->type = dma_debug_sg; entry->dev = dev; entry->paddr = sg_phys(s); - entry->size = s->length; - entry->dev_addr = s->dma_address; + entry->size = sg_dma_len(s); + entry->dev_addr = sg_dma_address(s); entry->direction = direction; entry->sg_call_ents = nents; entry->sg_mapped_ents = mapped_ents; if (!PageHighMem(sg_page(s))) { check_for_stack(dev, sg_virt(s)); - check_for_illegal_area(dev, sg_virt(s), s->length); + check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s)); } add_dma_entry(entry); @@ -739,13 +1036,33 @@ void debug_dma_map_sg(struct device *dev, struct scatterlist *sg, } EXPORT_SYMBOL(debug_dma_map_sg); +static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s) +{ + struct dma_debug_entry *entry, ref; + struct hash_bucket *bucket; + unsigned long flags; + int mapped_ents; + + ref.dev = dev; + ref.dev_addr = sg_dma_address(s); + ref.size = sg_dma_len(s), + + bucket = get_hash_bucket(&ref, &flags); + entry = hash_bucket_find(bucket, &ref); + mapped_ents = 0; + + if (entry) + mapped_ents = entry->sg_mapped_ents; + put_hash_bucket(bucket, &flags); + + return mapped_ents; +} + void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist, int nelems, int dir) { - struct dma_debug_entry *entry; struct scatterlist *s; int mapped_ents = 0, i; - unsigned long flags; if (unlikely(global_disable)) return; @@ -756,8 +1073,8 @@ void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist, .type = dma_debug_sg, .dev = dev, .paddr = sg_phys(s), - .dev_addr = s->dma_address, - .size = s->length, + .dev_addr = sg_dma_address(s), + .size = sg_dma_len(s), .direction = dir, .sg_call_ents = 0, }; @@ -765,14 +1082,9 @@ void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist, if (mapped_ents && i >= mapped_ents) break; - if (mapped_ents == 0) { - struct hash_bucket *bucket; + if (!i) { ref.sg_call_ents = nelems; - bucket = get_hash_bucket(&ref, &flags); - entry = hash_bucket_find(bucket, &ref); - if (entry) - mapped_ents = entry->sg_mapped_ents; - put_hash_bucket(bucket, &flags); + mapped_ents = get_nr_mapped_entries(dev, s); } check_unmap(&ref); @@ -874,14 +1186,20 @@ void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems, int direction) { struct scatterlist *s; - int i; + int mapped_ents = 0, i; if (unlikely(global_disable)) return; for_each_sg(sg, s, nelems, i) { - check_sync(dev, s->dma_address, s->dma_length, 0, - direction, true); + if (!i) + mapped_ents = get_nr_mapped_entries(dev, s); + + if (i >= mapped_ents) + break; + + check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0, + direction, true); } } EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu); @@ -890,15 +1208,39 @@ void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nelems, int direction) { struct scatterlist *s; - int i; + int mapped_ents = 0, i; if (unlikely(global_disable)) return; for_each_sg(sg, s, nelems, i) { - check_sync(dev, s->dma_address, s->dma_length, 0, - direction, false); + if (!i) + mapped_ents = get_nr_mapped_entries(dev, s); + + if (i >= mapped_ents) + break; + + check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0, + direction, false); } } EXPORT_SYMBOL(debug_dma_sync_sg_for_device); +static int __init dma_debug_driver_setup(char *str) +{ + int i; + + for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) { + current_driver_name[i] = *str; + if (*str == 0) + break; + } + + if (current_driver_name[0]) + pr_info("DMA-API: enable driver filter for driver [%s]\n", + current_driver_name); + + + return 1; +} +__setup("dma_debug_driver=", dma_debug_driver_setup); |