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| author | Dmitry Osipenko <digetx@gmail.com> | 2018-04-09 22:07:19 +0200 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2018-05-03 16:30:21 +0200 |
| commit | 40c9b882fa74771544b0e41209e99d78685f94be (patch) | |
| tree | 67d03a5173c67e8b156af51de4ba6f786d5685ef | |
| parent | Linux v4.17-rc3 (diff) | |
| download | linux-40c9b882fa74771544b0e41209e99d78685f94be.tar.xz linux-40c9b882fa74771544b0e41209e99d78685f94be.zip | |
iommu/tegra: gart: Add debugging facility
Page mapping could overwritten by an accident (a bug). We can catch this
case by checking 'VALID' bit of GART's page entry prior to mapping of a
page. Since that check introduces a small performance impact, it should be
enabled explicitly using new GART's kernel module 'debug' parameter.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
| -rw-r--r-- | drivers/iommu/tegra-gart.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c index b62f790ad1ba..4c0abdcd1ad2 100644 --- a/drivers/iommu/tegra-gart.c +++ b/drivers/iommu/tegra-gart.c @@ -72,6 +72,8 @@ struct gart_domain { static struct gart_device *gart_handle; /* unique for a system */ +static bool gart_debug; + #define GART_PTE(_pfn) \ (GART_ENTRY_PHYS_ADDR_VALID | ((_pfn) << PAGE_SHIFT)) @@ -271,6 +273,7 @@ static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova, struct gart_device *gart = gart_domain->gart; unsigned long flags; unsigned long pfn; + unsigned long pte; if (!gart_iova_range_valid(gart, iova, bytes)) return -EINVAL; @@ -282,6 +285,14 @@ static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova, spin_unlock_irqrestore(&gart->pte_lock, flags); return -EINVAL; } + if (gart_debug) { + pte = gart_read_pte(gart, iova); + if (pte & GART_ENTRY_PHYS_ADDR_VALID) { + spin_unlock_irqrestore(&gart->pte_lock, flags); + dev_err(gart->dev, "Page entry is in-use\n"); + return -EBUSY; + } + } gart_set_pte(gart, iova, GART_PTE(pfn)); FLUSH_GART_REGS(gart); spin_unlock_irqrestore(&gart->pte_lock, flags); @@ -515,7 +526,9 @@ static void __exit tegra_gart_exit(void) subsys_initcall(tegra_gart_init); module_exit(tegra_gart_exit); +module_param(gart_debug, bool, 0644); +MODULE_PARM_DESC(gart_debug, "Enable GART debugging"); MODULE_DESCRIPTION("IOMMU API for GART in Tegra20"); MODULE_AUTHOR("Hiroshi DOYU <hdoyu@nvidia.com>"); MODULE_ALIAS("platform:tegra-gart"); |