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>

5 files changed, 93 insertions, 75 deletions

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 6ee33169e1dc..7891904419fc 100644
--- a/drivers/acpi/Makefile
+++ b/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
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index c1d23cd71652..7136f24e3002 100644
--- a/drivers/acpi/bus.c
+++ b/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;
diff --git a/drivers/acpi/debug.c b/drivers/acpi/debug.c
index 146135e7a6a1..22476eab2b08 100644
--- a/drivers/acpi/debug.c
+++ b/drivers/acpi/debug.c
@@ -198,80 +198,6 @@ 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
@@ -400,7 +326,6 @@ int __init acpi_procfs_init(void)
 
 int __init acpi_debug_init(void)
 {
-        acpi_debugfs_init();
         acpi_procfs_init();
         return 0;
 }
diff --git a/drivers/acpi/debugfs.c b/drivers/acpi/debugfs.c
new file mode 100644
index 000000000000..abfcf9f6e766
--- /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;
+}
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index f8f190ec066e..0650e343867e 100644
--- a/drivers/acpi/internal.h
+++ b/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
    -------------------------------------------------------------------------- */