Any debugfs access on an OMAP IOMMU that is not enabled (done during
attach) results in a bus error due to access of registers without
the clock or the reset enabled for the respective IOMMU. So, add a
check to make sure the IOMMU is enabled/attached by a client device.
This gracefully prints a "Operation not permitted" trace when the
corresponding IOMMU is not enabled.
Signed-off-by: Suman Anna <s-anna@xxxxxx>
---
drivers/iommu/omap-iommu-debug.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/iommu/omap-iommu-debug.c b/drivers/iommu/omap-iommu-debug.c
index 54a0dc6..e7b8aca 100644
--- a/drivers/iommu/omap-iommu-debug.c
+++ b/drivers/iommu/omap-iommu-debug.c
@@ -24,6 +24,11 @@ static DEFINE_MUTEX(iommu_debug_lock);
static struct dentry *iommu_debug_root;
+static inline bool is_omap_iommu_detached(struct omap_iommu *obj)
+{
+ return !obj->domain;
+}
+
static ssize_t debug_read_regs(struct file *file, char __user *userbuf,
size_t count, loff_t *ppos)
{
@@ -31,6 +36,9 @@ static ssize_t debug_read_regs(struct file *file, char __user *userbuf,
char *p, *buf;
ssize_t bytes;
+ if (is_omap_iommu_detached(obj))
+ return -EPERM;
+
buf = kmalloc(count, GFP_KERNEL);
if (!buf)
return -ENOMEM;
@@ -54,6 +62,9 @@ static ssize_t debug_read_tlb(struct file *file, char __user *userbuf,
char *p, *buf;
ssize_t bytes, rest;
+ if (is_omap_iommu_detached(obj))
+ return -EPERM;
+
buf = kmalloc(count, GFP_KERNEL);
if (!buf)
return -ENOMEM;
@@ -139,6 +150,9 @@ static ssize_t debug_read_pagetable(struct file *file, char __user *userbuf,
char *p, *buf;
size_t bytes;
+ if (is_omap_iommu_detached(obj))
+ return -EPERM;
+
buf = (char *)__get_free_page(GFP_KERNEL);
if (!buf)
return -ENOMEM;
--
2.1.0
--
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