iommu/iommu-debug: Add debugfs file to trigger context faults

It can be useful during development to trigger faults.  Add a debugfs
file to do so.

Change-Id: Ic7b304ef0d908ebd506979f0c87189e34d7dfc67
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>

diff --git a/drivers/iommu/iommu-debug.c b/drivers/iommu/iommu-debug.c
index fba7679..3347af4 100644 (file)
--- a/drivers/iommu/iommu-debug.c
+++ b/drivers/iommu/iommu-debug.c
@@ -79,6 +79,23 @@ static const struct file_operations iommu_debug_attachment_info_fops = {
        .release = single_release,
 };
 
+static ssize_t iommu_debug_attachment_trigger_fault_write(
+       struct file *file, const char __user *ubuf, size_t count,
+       loff_t *offset)
+{
+       struct iommu_debug_attachment *attach = file->private_data;
+
+       iommu_trigger_fault(attach->domain);
+
+       return count;
+}
+
+static const struct file_operations
+iommu_debug_attachment_trigger_fault_fops = {
+       .open   = simple_open,
+       .write  = iommu_debug_attachment_trigger_fault_write,
+};
+
 void iommu_debug_attach_device(struct iommu_domain *domain,
                               struct device *dev)
 {
@@ -91,11 +108,11 @@ void iommu_debug_attach_device(struct iommu_domain *domain,
        uuid_le_gen(&uuid);
        attach_name = kasprintf(GFP_KERNEL, "%s-%pUl", dev_name(dev), uuid.b);
        if (!attach_name)
-               goto unlock;
+               goto err_unlock;
 
        attach = kmalloc(sizeof(*attach), GFP_KERNEL);
        if (!attach)
-               goto free_attach_name;
+               goto err_free_attach_name;
 
        attach->domain = domain;
        attach->dev = dev;
@@ -106,7 +123,7 @@ void iommu_debug_attach_device(struct iommu_domain *domain,
                pr_err("Couldn't create iommu/attachments/%s debugfs directory for domain 0x%p\n",
                       attach_name, domain);
                kfree(attach);
-               goto free_attach_name;
+               goto err_free_attach_name;
        }
 
        if (!debugfs_create_file(
@@ -114,15 +131,27 @@ void iommu_debug_attach_device(struct iommu_domain *domain,
                    &iommu_debug_attachment_info_fops)) {
                pr_err("Couldn't create iommu/attachments/%s/info debugfs file for domain 0x%p\n",
                       dev_name(dev), domain);
-               debugfs_remove_recursive(attach->dentry);
-               kfree(attach);
-               goto unlock;
+               goto err_rmdir;
+       }
+
+       if (!debugfs_create_file(
+                   "trigger_fault", S_IRUSR, attach->dentry, attach,
+                   &iommu_debug_attachment_trigger_fault_fops)) {
+               pr_err("Couldn't create iommu/attachments/%s/trigger_fault debugfs file for domain 0x%p\n",
+                      dev_name(dev), domain);
+               goto err_rmdir;
        }
 
        list_add(&attach->list, &iommu_debug_attachments);
-free_attach_name:
        kfree(attach_name);
-unlock:
+       mutex_unlock(&iommu_debug_attachments_lock);
+       return;
+err_rmdir:
+       debugfs_remove_recursive(attach->dentry);
+       kfree(attach);
+err_free_attach_name:
+       kfree(attach_name);
+err_unlock:
        mutex_unlock(&iommu_debug_attachments_lock);
 }