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Message-Id: <1239669799-23579-2-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Date: Tue, 14 Apr 2009 09:43:19 +0900
From: FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>
To: linux-kernel@...r.kernel.org, mingo@...e.hu
Cc: joerg.roedel@....com, fujita.tomonori@....ntt.co.jp
Subject: [PATCH 2/2] gart: reimplement IOMMU_LEAK feature by using DMA_API_DEBUG
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@....ntt.co.jp>
---
arch/x86/Kconfig.debug | 3 +-
arch/x86/kernel/pci-gart_64.c | 45 +++++++---------------------------------
2 files changed, 9 insertions(+), 39 deletions(-)
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index d8359e7..5865712 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -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.
diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index b284b58..1e8920d 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -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
--
1.6.0.6
--
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