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x86 gart: reimplement IOMMU_LEAK feature by using DMA_API_DEBUG

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IOMMU_LEAK, GART's own feature, dumps the used IOMMU entries when
IOMMU entries is full, which might be useful to find a bad driver that
eats IOMMU entries.

DMA_API_DEBUG provides the similar feature, debug_dma_dump_mappings,
and it's better than GART's IOMMU_LEAK feature. GART's IOMMU_LEAK
feature doesn't say who uses IOMMU entries so it's hard to find a bad
driver.

This patch reimplements the GART's IOMMU_LEAK feature by using
DMA_API_DEBUG.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1239669799-23579-2-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
FUJITA Tomonori 2009-04-14 09:43:19 +09:00 committed by Ingo Molnar
parent e6a1a89d57
commit 19c1a6f576
2 changed files with 9 additions and 39 deletions
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3
arch/x86/Kconfig.debug
View file

@ -161,8 +161,7 @@ config IOMMU_DEBUG
config IOMMU_LEAK
bool "IOMMU leak tracing"
depends on DEBUG_KERNEL
depends on IOMMU_DEBUG
depends on IOMMU_DEBUG && DMA_API_DEBUG
---help---
Add a simple leak tracer to the IOMMU code. This is useful when you
are debugging a buggy device driver that leaks IOMMU mappings.

45
arch/x86/kernel/pci-gart_64.c
View file

@ -144,48 +144,21 @@ static void flush_gart(void)
}
#ifdef CONFIG_IOMMU_LEAK
#define SET_LEAK(x) \
do { \
if (iommu_leak_tab) \
iommu_leak_tab[x] = __builtin_return_address(0);\
} while (0)
#define CLEAR_LEAK(x) \
do { \
if (iommu_leak_tab) \
iommu_leak_tab[x] = NULL; \
} while (0)
/* Debugging aid for drivers that don't free their IOMMU tables */
static void **iommu_leak_tab;
static int leak_trace;
static int iommu_leak_pages = 20;
static void dump_leak(void)
{
int i;
static int dump;
if (dump || !iommu_leak_tab)
if (dump)
return;
dump = 1;
show_stack(NULL, NULL);
/* Very crude. dump some from the end of the table too */
printk(KERN_DEBUG "Dumping %d pages from end of IOMMU:\n",
iommu_leak_pages);
for (i = 0; i < iommu_leak_pages; i += 2) {
printk(KERN_DEBUG "%lu: ", iommu_pages-i);
printk_address((unsigned long) iommu_leak_tab[iommu_pages-i],
0);
printk(KERN_CONT "%c", (i+1)%2 == 0 ? '\n' : ' ');
}
printk(KERN_DEBUG "\n");
show_stack(NULL, NULL);
debug_dma_dump_mappings(NULL);
}
#else
# define SET_LEAK(x)
# define CLEAR_LEAK(x)
#endif
static void iommu_full(struct device *dev, size_t size, int dir)
@ -248,7 +221,6 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
for (i = 0; i < npages; i++) {
iommu_gatt_base[iommu_page + i] = GPTE_ENCODE(phys_mem);
SET_LEAK(iommu_page + i);
phys_mem += PAGE_SIZE;
}
return iommu_bus_base + iommu_page*PAGE_SIZE + (phys_mem & ~PAGE_MASK);
@ -294,7 +266,6 @@ static void gart_unmap_page(struct device *dev, dma_addr_t dma_addr,
npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
for (i = 0; i < npages; i++) {
iommu_gatt_base[iommu_page + i] = gart_unmapped_entry;
CLEAR_LEAK(iommu_page + i);
}
free_iommu(iommu_page, npages);
}
@ -377,7 +348,6 @@ static int __dma_map_cont(struct device *dev, struct scatterlist *start,
pages = iommu_num_pages(s->offset, s->length, PAGE_SIZE);
while (pages--) {
iommu_gatt_base[iommu_page] = GPTE_ENCODE(addr);
SET_LEAK(iommu_page);
addr += PAGE_SIZE;
iommu_page++;
}
@ -801,11 +771,12 @@ void __init gart_iommu_init(void)
#ifdef CONFIG_IOMMU_LEAK
if (leak_trace) {
iommu_leak_tab = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
get_order(iommu_pages*sizeof(void *)));
if (!iommu_leak_tab)
int ret;
ret = dma_debug_resize_entries(iommu_pages);
if (ret)
printk(KERN_DEBUG
"PCI-DMA: Cannot allocate leak trace area\n");
"PCI-DMA: Cannot trace all the entries\n");
}
#endif