1 files changed, 83 insertions, 1 deletions

diff --git a/drivers/acpi/debug.c b/drivers/acpi/debug.c
index 8a690c3b8e23..cc421b7ae166 100644
--- a/drivers/acpi/debug.c
+++ b/drivers/acpi/debug.c
@@ -8,6 +8,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/moduleparam.h>
+#include <linux/debugfs.h>
 #include <asm/uaccess.h>
 #include <acpi/acpi_drivers.h>
 
@@ -196,6 +197,80 @@ module_param_call(trace_state, param_set_trace_state, param_get_trace_state,
                   NULL, 0644);
 
 /* --------------------------------------------------------------------------
+                                DebugFS Interface
+   -------------------------------------------------------------------------- */
+
+static ssize_t cm_write(struct file *file, const char __user *user_buf,
+                        size_t count, loff_t *ppos)
+{
+        static char *buf;
+        static int uncopied_bytes;
+        struct acpi_table_header table;
+        acpi_status status;
+
+        if (!(*ppos)) {
+                /* parse the table header to get the table length */
+                if (count <= sizeof(struct acpi_table_header))
+                        return -EINVAL;
+                if (copy_from_user(&table, user_buf,
+                        sizeof(struct acpi_table_header)))
+                        return -EFAULT;
+                uncopied_bytes = table.length;
+                buf = kzalloc(uncopied_bytes, GFP_KERNEL);
+                if (!buf)
+                        return -ENOMEM;
+        }
+
+        if (uncopied_bytes < count) {
+                kfree(buf);
+                return -EINVAL;
+        }
+
+        if (copy_from_user(buf + (*ppos), user_buf, count)) {
+                kfree(buf);
+                return -EFAULT;
+        }
+
+        uncopied_bytes -= count;
+        *ppos += count;
+
+        if (!uncopied_bytes) {
+                status = acpi_install_method(buf);
+                kfree(buf);
+                if (ACPI_FAILURE(status))
+                        return -EINVAL;
+                add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
+        }
+
+        return count;
+}
+
+static const struct file_operations cm_fops = {
+        .write = cm_write,
+};
+
+static int acpi_debugfs_init(void)
+{
+        struct dentry *acpi_dir, *cm_dentry;
+
+        acpi_dir = debugfs_create_dir("acpi", NULL);
+        if (!acpi_dir)
+                goto err;
+
+        cm_dentry = debugfs_create_file("custom_method", S_IWUGO,
+                                        acpi_dir, NULL, &cm_fops);
+        if (!cm_dentry)
+                goto err;
+
+        return 0;
+
+err:
+        if (acpi_dir)
+                debugfs_remove(acpi_dir);
+        return -EINVAL;
+}
+
+/* --------------------------------------------------------------------------
                               FS Interface (/proc)
    -------------------------------------------------------------------------- */
 #ifdef CONFIG_ACPI_PROCFS
@@ -286,7 +361,7 @@ static const struct file_operations acpi_system_debug_proc_fops = {
 };
 #endif
 
-int __init acpi_debug_init(void)
+int __init acpi_procfs_init(void)
 {
 #ifdef CONFIG_ACPI_PROCFS
         struct proc_dir_entry *entry;
@@ -321,3 +396,10 @@ int __init acpi_debug_init(void)
         return 0;
 #endif
 }
+
+int __init acpi_debug_init(void)
+{
+        acpi_debugfs_init();
+        acpi_procfs_init();
+        return 0;
+}