iommu/core: pass a user-provided token to fault handlers

Sometimes a single IOMMU user may have to deal with several
different IOMMU devices (e.g. remoteproc).

When an IOMMU fault happens, such users have to regain their
context in order to deal with the fault.

Users can't use the private fields of neither the iommu_domain nor
the IOMMU device, because those are already used by the IOMMU core
and low level driver (respectively).

This patch just simply allows users to pass a private token (most
notably their own context pointer) to iommu_set_fault_handler(),
and then makes sure it is provided back to the users whenever
an IOMMU fault happens.

The patch also adopts remoteproc to the new fault handling
interface, but the real functionality using this (recovery of
remote processors) will only be added later in a subsequent patch
set.

Cc: Fernando Guzman Lugo <fernando.lugo@ti.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 2198b2dbbcd3ad964b03a13dd6fd8dd336f27bed..8b9ded88e6f5322c18c02ec6e685b05d8decfd29 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -119,6 +119,7 @@ EXPORT_SYMBOL_GPL(iommu_present);
  * iommu_set_fault_handler() - set a fault handler for an iommu domain
  * @domain: iommu domain
  * @handler: fault handler
+ * @token: user data, will be passed back to the fault handler
  *
  * This function should be used by IOMMU users which want to be notified
  * whenever an IOMMU fault happens.
@@ -127,11 +128,13 @@ EXPORT_SYMBOL_GPL(iommu_present);
  * error code otherwise.
  */
 void iommu_set_fault_handler(struct iommu_domain *domain,
-                                       iommu_fault_handler_t handler)
+                                       iommu_fault_handler_t handler,
+                                       void *token)
 {
        BUG_ON(!domain);
 
        domain->handler = handler;
+       domain->handler_token = token;
 }
 EXPORT_SYMBOL_GPL(iommu_set_fault_handler);
 

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index e756a0df3664e0dd60ee8129449840347b5bdf42..289293a5cbb08f2e042314f7d6933dfbd6499c2d 100644 (file)
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -78,7 +78,7 @@ typedef int (*rproc_handle_resource_t)(struct rproc *rproc, void *, int avail);
  * the recovery of the remote processor.
  */
 static int rproc_iommu_fault(struct iommu_domain *domain, struct device *dev,
-               unsigned long iova, int flags)
+               unsigned long iova, int flags, void *token)
 {
        dev_err(dev, "iommu fault: da 0x%lx flags 0x%x\n", iova, flags);
 
@@ -117,7 +117,7 @@ static int rproc_enable_iommu(struct rproc *rproc)
                return -ENOMEM;
        }
 
-       iommu_set_fault_handler(domain, rproc_iommu_fault);
+       iommu_set_fault_handler(domain, rproc_iommu_fault, rproc);
 
        ret = iommu_attach_device(domain, dev);
        if (ret) {

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index d937580417ba668d343b30b1741d59139f7924b9..450293f6d68b6a9bfdbd74fdc3304a63c122505a 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -35,12 +35,13 @@ struct iommu_domain;
 #define IOMMU_FAULT_WRITE      0x1
 
 typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
-                               struct device *, unsigned long, int);
+                       struct device *, unsigned long, int, void *);
 
 struct iommu_domain {
        struct iommu_ops *ops;
        void *priv;
        iommu_fault_handler_t handler;
+       void *handler_token;
 };
 
 #define IOMMU_CAP_CACHE_COHERENCY      0x1
@@ -95,7 +96,7 @@ extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
 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);
+                       iommu_fault_handler_t handler, void *token);
 extern int iommu_device_group(struct device *dev, unsigned int *groupid);
 
 /**
@@ -132,7 +133,8 @@ static inline int report_iommu_fault(struct iommu_domain *domain,
         * invoke it.
         */
        if (domain->handler)
-               ret = domain->handler(domain, dev, iova, flags);
+               ret = domain->handler(domain, dev, iova, flags,
+                                               domain->handler_token);
 
        return ret;
 }
@@ -191,7 +193,7 @@ static inline int domain_has_cap(struct iommu_domain *domain,
 }
 
 static inline void iommu_set_fault_handler(struct iommu_domain *domain,
-                                       iommu_fault_handler_t handler)
+                               iommu_fault_handler_t handler, void *token)
 {
 }