ACPI / debugger: Add IO interface to access debugger functionalities

This patch adds /sys/kernel/debug/acpi/acpidbg, which can be used by
userspace programs to access ACPICA debugger functionalities.

Known issue:
1. IO flush support
   acpi_os_notify_command_complete() and acpi_os_wait_command_ready() can
   be used by acpi_dbg module to implement .flush() filesystem operation.
   While this patch doesn't go that far. It then becomes userspace tool's
   duty now to flush old commands before executing new batch mode commands.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 51 insertions, 4 deletions

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 32d684af0ec7..4c1339819bfc 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -40,6 +40,7 @@
 #include <linux/list.h>
 #include <linux/jiffies.h>
 #include <linux/semaphore.h>
+#include <linux/acpi_dbg.h>
 
 #include <asm/io.h>
 #include <asm/uaccess.h>
@@ -234,7 +235,8 @@ void acpi_os_vprintf(const char *fmt, va_list args)
 		printk(KERN_CONT "%s", buffer);
 	}
 #else
-	printk(KERN_CONT "%s", buffer);
+	if (acpi_aml_write_log(buffer) < 0)
+		printk(KERN_CONT "%s", buffer);
 #endif
 }
 
@@ -1127,6 +1129,15 @@ acpi_status acpi_os_execute(acpi_execute_type type,
 			  "Scheduling function [%p(%p)] for deferred execution.\n",
 			  function, context));
 
+	if (type == OSL_DEBUGGER_MAIN_THREAD) {
+		ret = acpi_aml_create_thread(function, context);
+		if (ret) {
+			pr_err("Call to kthread_create() failed.\n");
+			status = AE_ERROR;
+		}
+		goto out_thread;
+	}
+
 	/*
 	 * Allocate/initialize DPC structure.  Note that this memory will be
 	 * freed by the callee.  The kernel handles the work_struct list  in a
@@ -1151,11 +1162,17 @@ acpi_status acpi_os_execute(acpi_execute_type type,
 	if (type == OSL_NOTIFY_HANDLER) {
 		queue = kacpi_notify_wq;
 		INIT_WORK(&dpc->work, acpi_os_execute_deferred);
-	} else {
+	} else if (type == OSL_GPE_HANDLER) {
 		queue = kacpid_wq;
 		INIT_WORK(&dpc->work, acpi_os_execute_deferred);
+	} else {
+		pr_err("Unsupported os_execute type %d.\n", type);
+		status = AE_ERROR;
 	}
 
+	if (ACPI_FAILURE(status))
+		goto err_workqueue;
+
 	/*
 	 * On some machines, a software-initiated SMI causes corruption unless
 	 * the SMI runs on CPU 0.  An SMI can be initiated by any AML, but
@@ -1164,13 +1181,15 @@ acpi_status acpi_os_execute(acpi_execute_type type,
 	 * queueing on CPU 0.
 	 */
 	ret = queue_work_on(0, queue, &dpc->work);
-
 	if (!ret) {
 		printk(KERN_ERR PREFIX
 			  "Call to queue_work() failed.\n");
 		status = AE_ERROR;
-		kfree(dpc);
 	}
+err_workqueue:
+	if (ACPI_FAILURE(status))
+		kfree(dpc);
+out_thread:
 	return status;
 }
 EXPORT_SYMBOL(acpi_os_execute);
@@ -1358,11 +1377,39 @@ acpi_status acpi_os_get_line(char *buffer, u32 buffer_length, u32 *bytes_read)
 		chars = strlen(buffer) - 1;
 		buffer[chars] = '\0';
 	}
+#else
+	int ret;
+
+	ret = acpi_aml_read_cmd(buffer, buffer_length);
+	if (ret < 0)
+		return AE_ERROR;
+	if (bytes_read)
+		*bytes_read = ret;
 #endif
 
 	return AE_OK;
 }
 
+acpi_status acpi_os_wait_command_ready(void)
+{
+	int ret;
+
+	ret = acpi_aml_wait_command_ready();
+	if (ret < 0)
+		return AE_ERROR;
+	return AE_OK;
+}
+
+acpi_status acpi_os_notify_command_complete(void)
+{
+	int ret;
+
+	ret = acpi_aml_notify_command_complete();
+	if (ret < 0)
+		return AE_ERROR;
+	return AE_OK;
+}
+
 acpi_status acpi_os_signal(u32 function, void *info)
 {
 	switch (function) {