Add iommu fault report mechanism to the IOMMU API, so implementations
could report about mmu faults (translation errors, hardware errors,
etc..).
Fault reports can be used in several ways:
- mere logging
- reset the device that accessed the faulting address (may be necessary
in case the device is a remote processor for example)
- implement dynamic PTE/TLB loading
A dedicated iommu_set_fault_handler() API has been added to allow
users, who are interested to receive such reports, to provide
their handler.
Signed-off-by: Ohad Ben-Cohen <ohad@xxxxxxxxxx>
---
v1->v2: remove 'event' parameter
drivers/iommu/iommu.c | 13 ++++++++++++
include/linux/iommu.h | 51 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 64 insertions(+), 0 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index e61a9ba..c68ff29 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -40,6 +40,19 @@ bool iommu_found(void)
}
EXPORT_SYMBOL_GPL(iommu_found);
+/**
+ * iommu_domain_alloc() - set a fault handler for an iommu domain
+ * @domain: iommu domain
+ * @handler: fault handler
+ */
+void iommu_set_fault_handler(struct iommu_domain *domain,
+ iommu_fault_handler_t handler)
+{
+ BUG_ON(!domain);
+
+ domain->handler = handler;
+}
+
struct iommu_domain *iommu_domain_alloc(void)
{
struct iommu_domain *domain;
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 9940319..d084e87 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -26,9 +26,18 @@
#define IOMMU_CACHE (4) /* DMA cache coherency */
struct device;
+struct iommu_domain;
+
+/* iommu fault flags */
+#define IOMMU_FAULT_READ 0x0
+#define IOMMU_FAULT_WRITE 0x1
+
+typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
+ struct device *, unsigned long, int);
struct iommu_domain {
void *priv;
+ iommu_fault_handler_t handler;
};
#define IOMMU_CAP_CACHE_COHERENCY 0x1
@@ -67,6 +76,43 @@ extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
unsigned long iova);
extern int iommu_domain_has_cap(struct iommu_domain *domain,
unsigned long cap);
+extern void iommu_set_fault_handler(struct iommu_domain *domain,
+ iommu_fault_handler_t handler);
+
+/**
+ * report_iommu_fault() - report about an IOMMU fault to the IOMMU framework
+ * @domain: the iommu domain where the fault has happened
+ * @dev: the device where the fault has happened
+ * @iova: the faulting address
+ * @flags: mmu fault flags (e.g. IOMMU_FAULT_READ/IOMMU_FAULT_WRITE/...)
+ *
+ * This function should be called by the low-level IOMMU implementations
+ * whenever IOMMU faults happen, to allow high-level users, that are
+ * interested in such events, to know about them.
+ *
+ * This event may be useful for several possible use cases:
+ * - mere logging of the event
+ * - dynamic TLB/PTE loading
+ * - if restarting of the faulting device is required
+ *
+ * Returns 0 on success and an appropriate error code otherwise (if dynamic
+ * PTE/TLB loading will one day be supported, implementations will be able
+ * to tell whether it succeeded or not according to this return value).
+ */
+static inline int report_iommu_fault(struct iommu_domain *domain,
+ struct device *dev, unsigned long iova, int flags)
+{
+ int ret = 0;
+
+ /*
+ * if upper layers showed interest and installed a fault handler,
+ * invoke it.
+ */
+ if (domain->handler)
+ ret = domain->handler(domain, dev, iova, flags);
+
+ return ret;
+}
#else /* CONFIG_IOMMU_API */
@@ -123,6 +169,11 @@ static inline int domain_has_cap(struct iommu_domain *domain,
return 0;
}
+static inline void iommu_set_fault_handler(struct iommu_domain *domain,
+ iommu_fault_handler_t handler)
+{
+}
+
#endif /* CONFIG_IOMMU_API */
#endif /* __LINUX_IOMMU_H */
--
1.7.4.1
--
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