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>

drivers/acpi/Makefile

@@ -39,6 +39,7 @@ acpi-y				+= pci_root.o pci_link.o pci_irq.o pci_bind.o
 acpi-y				+= power.o
 acpi-y				+= system.o event.o
 acpi-$(CONFIG_ACPI_DEBUG)	+= debug.o
+acpi-$(CONFIG_DEBUG_FS)		+= debugfs.o
 acpi-$(CONFIG_ACPI_NUMA)	+= numa.o
 acpi-$(CONFIG_ACPI_PROCFS_POWER) += cm_sbs.o
 ifdef CONFIG_ACPI_VIDEO

drivers/acpi/bus.c

@@ -1036,6 +1036,7 @@ static int __init acpi_init(void)
 	acpi_power_init();
 	acpi_system_init();
 	acpi_debug_init();
+	acpi_debugfs_init();
 	acpi_sleep_proc_init();
 	acpi_wakeup_device_init();
 	return result;

drivers/acpi/debug.c

@@ -197,80 +197,6 @@ static int param_get_trace_state(char *buffer, struct kernel_param *kp)
 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)
    -------------------------------------------------------------------------- */
@@ -400,7 +326,6 @@ int __init acpi_procfs_init(void)
 
 int __init acpi_debug_init(void)
 {
-	acpi_debugfs_init();
 	acpi_procfs_init();
 	return 0;
 }

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;
+}

drivers/acpi/internal.h

@@ -30,6 +30,12 @@ int acpi_debug_init(void);
 static inline int acpi_debug_init(void) { return 0; }
 #endif
 
+#ifdef CONFIG_DEBUG_FS
+int acpi_debugfs_init(void);
+#else
+static inline int acpi_debugfs_init(void) { return 0; }
+#endif
+
 /* --------------------------------------------------------------------------
                                   Power Resource
    -------------------------------------------------------------------------- */