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authorZhang Rui <rui.zhang@intel.com>2009-12-02 13:31:00 +0800
committerLen Brown <len.brown@intel.com>2009-12-11 01:50:08 -0500
commita1a541d86f50a9957beeedb122a035870d602647 (patch)
treebc3bd16c6d1bbb8c1fcc561a436b2c322ec098d4 /drivers/acpi
parent22763c5cf3690a681551162c15d34d935308c8d7 (diff)
ACPI: support customizing ACPI control methods at runtime
Introduce a new debugfs I/F (/sys/kernel/debug/acpi/custom_method) for ACPI, which can be used to customize the ACPI control methods at runtime. We can use this to debug the AML code level bugs instead of overriding the whole DSDT table, without rebuilding/rebooting kernel any more. Detailed description about how to use this debugfs I/F is stated in Documentation/acpi/method-customizing.txt Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/debug.c83
1 files changed, 82 insertions, 1 deletions
diff --git a/drivers/acpi/debug.c b/drivers/acpi/debug.c
index 8a690c3b8e2..0bedd1554f2 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 +197,79 @@ 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;
+ }
+
+ 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 +360,7 @@ 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 +395,10 @@ int __init acpi_debug_init(void)
return 0;
#endif
}
+
+int __init acpi_debug_init(void)
+{
+ acpi_debugfs_init();
+ acpi_procfs_init();
+ return 0;
+}