From c5cf5c5377fbd0a1ff2a09ad1f0c7e261aabc567 Mon Sep 17 00:00:00 2001 From: Suman Anna Date: Wed, 22 Oct 2014 17:22:34 -0500 Subject: iommu/omap: Fix bus error on debugfs access of unattached IOMMU 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 Acked-by: Laurent Pinchart Signed-off-by: Joerg Roedel --- drivers/iommu/omap-iommu-debug.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'drivers') diff --git a/drivers/iommu/omap-iommu-debug.c b/drivers/iommu/omap-iommu-debug.c index 4813d3a71a00..41b09a1d78ea 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; -- cgit v1.2.3