ACPI: introduce drivers/acpi/debugfs.c
Introduce drivers/acpi/debugfs.c.
Code for ACPI debugfs I/F,
i.e. /sys/kernel/debug/acpi/custom_method,
is moved to this file.
And make ACPI debugfs always built in,
even if CONFIG_ACPI_DEBUG is cleared.
BTW:this adds about 400bytes code to ACPI, when
CONFIG_ACPI_DEBUG is cleared.
[uaccess.h build fix from Andrew Morton <akpm@linux-foundation.org>]
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/debugfs.c b/drivers/acpi/debugfs.c
new file mode 100644
index 0000000..abfcf9f
--- /dev/null
+++ b/drivers/acpi/debugfs.c
@@ -0,0 +1,85 @@
+/*
+ * debugfs.c - ACPI debugfs interface to userspace.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/uaccess.h>
+#include <linux/debugfs.h>
+#include <acpi/acpi_drivers.h>
+
+#define _COMPONENT ACPI_SYSTEM_COMPONENT
+ACPI_MODULE_NAME("debugfs");
+
+/* /sys/kernel/debug/acpi/custom_method */
+
+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,
+};
+
+int __init 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;
+}