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iommu/omap: Fix bus error on debugfs access of unattached IOMMU

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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@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Suman Anna 2014-10-22 17:22:34 -05:00 committed by Joerg Roedel
parent f24d9ad3fa
commit c5cf5c5377
1 changed files with 14 additions and 0 deletions
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14
drivers/iommu/omap-iommu-debug.c
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@ -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;