[PATCH v2 7/7] ACPI / debugger: Add module support for ACPI debugger

From: Lv Zheng
Date: Tue Nov 10 2015 - 03:22:36 EST

This patch converts AML debugger into a loadable module.

Note that, it implements driver unloading at the level dependent on the
module reference count. Which means if ACPI debugger is being used by a
userspace program, "rmmod acpi_dbg" should result in failure.

Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
---
drivers/acpi/Kconfig | 12 ++-
drivers/acpi/Makefile | 2 +-
drivers/acpi/acpi_dbg.c | 80 ++++++++++++------
drivers/acpi/bus.c | 3 +-
drivers/acpi/osl.c | 207 ++++++++++++++++++++++++++++++++++++++++++++--
include/linux/acpi.h | 71 ++++++++++++++++
include/linux/acpi_dbg.h | 52 ------------
7 files changed, 338 insertions(+), 89 deletions(-)
delete mode 100644 include/linux/acpi_dbg.h

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index e67b1b5..73b45f9 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -63,13 +63,23 @@ config ACPI_MEMORY_ACCESS_CHECK_SUPPORT
config ACPI_DEBUGGER
bool "In-kernel debugger"
select ACPI_DEBUG
- depends on DEBUG_FS
help
Enable in-kernel debugging facilities: statistics, internal
object dump, single step control method execution.
This is still under development, currently enabling this only
results in the compilation of the ACPICA debugger files.

+if ACPI_DEBUGGER
+
+config ACPI_DEBUGGER_USER
+ tristate "Userspace debugger accessiblity"
+ depends on DEBUG_FS
+ help
+ Export /sys/kernel/debug/acpi/acpidbg for userspace utilities
+ to access the debugger functionalities.
+
+endif
+
config ACPI_SLEEP
bool
depends on SUSPEND || HIBERNATION
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 102b5e6..c6f236f 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -50,7 +50,6 @@ acpi-y += sysfs.o
acpi-y += property.o
acpi-$(CONFIG_X86) += acpi_cmos_rtc.o
acpi-$(CONFIG_DEBUG_FS) += debugfs.o
-acpi-$(CONFIG_ACPI_DEBUGGER) += acpi_dbg.o
acpi-$(CONFIG_ACPI_NUMA) += numa.o
acpi-$(CONFIG_ACPI_PROCFS_POWER) += cm_sbs.o
acpi-y += acpi_lpat.o
@@ -80,6 +79,7 @@ obj-$(CONFIG_ACPI_EC_DEBUGFS) += ec_sys.o
obj-$(CONFIG_ACPI_CUSTOM_METHOD)+= custom_method.o
obj-$(CONFIG_ACPI_BGRT) += bgrt.o
obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o
+obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o

# processor has its own "processor." module_param namespace
processor-y := processor_driver.o
diff --git a/drivers/acpi/acpi_dbg.c b/drivers/acpi/acpi_dbg.c
index 7be0851..8fcf752 100644
--- a/drivers/acpi/acpi_dbg.c
+++ b/drivers/acpi/acpi_dbg.c
@@ -21,7 +21,7 @@
#include <linux/proc_fs.h>
#include <linux/debugfs.h>
#include <linux/circ_buf.h>
-#include <linux/acpi_dbg.h>
+#include <linux/acpi.h>
#include "internal.h"

#define ACPI_AML_BUF_ALIGN (sizeof (acpi_size))
@@ -307,7 +307,7 @@ static int acpi_aml_readb_kern(void)
* the debugger output and store the output into the debugger interface
* buffer. Return the size of stored logs or errno.
*/
-ssize_t acpi_aml_write_log(const char *msg)
+static ssize_t acpi_aml_write_log(const char *msg)
{
int ret = 0;
int count = 0, size = 0;
@@ -350,7 +350,6 @@ again:
}
return size > 0 ? size : ret;
}
-EXPORT_SYMBOL(acpi_aml_write_log);

/*
* acpi_aml_read_cmd() - Capture debugger input
@@ -361,7 +360,7 @@ EXPORT_SYMBOL(acpi_aml_write_log);
* the debugger input commands and store the input commands into the
* debugger interface buffer. Return the size of stored commands or errno.
*/
-ssize_t acpi_aml_read_cmd(char *msg, size_t count)
+static ssize_t acpi_aml_read_cmd(char *msg, size_t count)
{
int ret = 0;
int size = 0;
@@ -403,7 +402,6 @@ again:
}
return size > 0 ? size : ret;
}
-EXPORT_SYMBOL(acpi_aml_read_cmd);

static int acpi_aml_thread(void *unsed)
{
@@ -440,7 +438,7 @@ static int acpi_aml_thread(void *unsed)
* This function should be used to implement acpi_os_execute() which is
* used by the ACPICA debugger to create the debugger thread.
*/
-int acpi_aml_create_thread(acpi_osd_exec_callback function, void *context)
+static int acpi_aml_create_thread(acpi_osd_exec_callback function, void *context)
{
struct task_struct *t;

@@ -462,30 +460,27 @@ int acpi_aml_create_thread(acpi_osd_exec_callback function, void *context)
mutex_unlock(&acpi_aml_io.lock);
return 0;
}
-EXPORT_SYMBOL(acpi_aml_create_thread);

-int acpi_aml_wait_command_ready(void)
+static int acpi_aml_wait_command_ready(bool single_step,
+ char *buffer, size_t length)
{
acpi_status status;

- if (!acpi_gbl_method_executing)
- acpi_os_printf("\n%1c ", ACPI_DEBUGGER_COMMAND_PROMPT);
- else
+ if (single_step)
acpi_os_printf("\n%1c ", ACPI_DEBUGGER_EXECUTE_PROMPT);
+ else
+ acpi_os_printf("\n%1c ", ACPI_DEBUGGER_COMMAND_PROMPT);

- status = acpi_os_get_line(acpi_gbl_db_line_buf,
- ACPI_DB_LINE_BUFFER_SIZE, NULL);
+ status = acpi_os_get_line(buffer, length, NULL);
if (ACPI_FAILURE(status))
return -EINVAL;
return 0;
}
-EXPORT_SYMBOL(acpi_aml_wait_command_ready);

-int acpi_aml_notify_command_complete(void)
+static int acpi_aml_notify_command_complete(void)
{
return 0;
}
-EXPORT_SYMBOL(acpi_aml_notify_command_complete);

static int acpi_aml_open(struct inode *inode, struct file *file)
{
@@ -759,10 +754,23 @@ static const struct file_operations acpi_aml_operations = {
.llseek = generic_file_llseek,
};

+static const struct acpi_debugger_ops acpi_aml_debugger = {
+ .create_thread = acpi_aml_create_thread,
+ .read_cmd = acpi_aml_read_cmd,
+ .write_log = acpi_aml_write_log,
+ .wait_command_ready = acpi_aml_wait_command_ready,
+ .notify_command_complete = acpi_aml_notify_command_complete,
+};
+
int __init acpi_aml_init(void)
{
- if (!acpi_debugfs_dir)
- return -ENOENT;
+ int ret = 0;
+
+ if (!acpi_debugfs_dir) {
+ ret = -ENOENT;
+ goto err_exit;
+ }
+
/* Initialize AML IO interface */
mutex_init(&acpi_aml_io.lock);
init_waitqueue_head(&acpi_aml_io.wait);
@@ -772,21 +780,39 @@ int __init acpi_aml_init(void)
S_IFREG | S_IRUGO | S_IWUSR,
acpi_debugfs_dir, NULL,
&acpi_aml_operations);
- if (acpi_aml_dentry == NULL)
- return -ENODEV;
+ if (acpi_aml_dentry == NULL) {
+ ret = -ENODEV;
+ goto err_exit;
+ }
+ ret = acpi_register_debugger(THIS_MODULE, &acpi_aml_debugger);
+ if (ret)
+ goto err_fs;
acpi_aml_initialized = true;
- return 0;
+
+err_fs:
+ if (ret) {
+ debugfs_remove(acpi_aml_dentry);
+ acpi_aml_dentry = NULL;
+ }
+err_exit:
+ return ret;
}

-#if 0
void __exit acpi_aml_exit(void)
{
- /* TODO: Stop the in kernel debugger */
- if (acpi_aml_dentry)
- debugfs_remove(acpi_aml_dentry);
- acpi_aml_initialized = false;
+ if (acpi_aml_initialized) {
+ acpi_unregister_debugger(&acpi_aml_debugger);
+ if (acpi_aml_dentry) {
+ debugfs_remove(acpi_aml_dentry);
+ acpi_aml_dentry = NULL;
+ }
+ acpi_aml_initialized = false;
+ }
}

module_init(acpi_aml_init);
module_exit(acpi_aml_exit);
-#endif
+
+MODULE_AUTHOR("Lv Zheng");
+MODULE_DESCRIPTION("ACPI debugger userspace IO driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 06fbba9..1a40111 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -37,7 +37,6 @@
#include <acpi/apei.h>
#include <linux/dmi.h>
#include <linux/suspend.h>
-#include <linux/acpi_dbg.h>

#include "internal.h"

@@ -1095,7 +1094,7 @@ static int __init acpi_init(void)
acpi_debugfs_init();
acpi_sleep_proc_init();
acpi_wakeup_device_init();
- acpi_aml_init();
+ acpi_debugger_init();
return 0;
}

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index bc3da95..17fb138 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -40,7 +40,6 @@
#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>
@@ -220,6 +219,7 @@ void acpi_os_printf(const char *fmt, ...)
acpi_os_vprintf(fmt, args);
va_end(args);
}
+EXPORT_SYMBOL(acpi_os_printf);

void acpi_os_vprintf(const char *fmt, va_list args)
{
@@ -234,7 +234,7 @@ void acpi_os_vprintf(const char *fmt, va_list args)
printk(KERN_CONT "%s", buffer);
}
#else
- if (acpi_aml_write_log(buffer) < 0)
+ if (acpi_debugger_write_log(buffer) < 0)
printk(KERN_CONT "%s", buffer);
#endif
}
@@ -1100,6 +1100,200 @@ static void acpi_os_execute_deferred(struct work_struct *work)
kfree(dpc);
}

+#ifdef CONFIG_ACPI_DEBUGGER
+static struct acpi_debugger acpi_debugger;
+static bool acpi_debugger_initialized;
+
+int acpi_register_debugger(struct module *owner,
+ const struct acpi_debugger_ops *ops)
+{
+ int ret = 0;
+
+ mutex_lock(&acpi_debugger.lock);
+ if (acpi_debugger.ops) {
+ ret = -EBUSY;
+ goto err_lock;
+ }
+
+ acpi_debugger.owner = owner;
+ acpi_debugger.ops = ops;
+
+err_lock:
+ mutex_unlock(&acpi_debugger.lock);
+ return ret;
+}
+EXPORT_SYMBOL(acpi_register_debugger);
+
+void acpi_unregister_debugger(const struct acpi_debugger_ops *ops)
+{
+ mutex_lock(&acpi_debugger.lock);
+ if (ops == acpi_debugger.ops) {
+ acpi_debugger.ops = NULL;
+ acpi_debugger.owner = NULL;
+ }
+ mutex_unlock(&acpi_debugger.lock);
+}
+EXPORT_SYMBOL(acpi_unregister_debugger);
+
+int acpi_debugger_create_thread(acpi_osd_exec_callback function, void *context)
+{
+ int ret;
+ int (*func)(acpi_osd_exec_callback, void *);
+ struct module *owner;
+
+ if (!acpi_debugger_initialized)
+ return -ENODEV;
+ mutex_lock(&acpi_debugger.lock);
+ if (!acpi_debugger.ops) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ if (!try_module_get(acpi_debugger.owner)) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ func = acpi_debugger.ops->create_thread;
+ owner = acpi_debugger.owner;
+ mutex_unlock(&acpi_debugger.lock);
+
+ ret = func(function, context);
+
+ mutex_lock(&acpi_debugger.lock);
+ module_put(owner);
+err_lock:
+ mutex_unlock(&acpi_debugger.lock);
+ return ret;
+}
+
+ssize_t acpi_debugger_write_log(const char *msg)
+{
+ ssize_t ret;
+ ssize_t (*func)(const char *);
+ struct module *owner;
+
+ if (!acpi_debugger_initialized)
+ return -ENODEV;
+ mutex_lock(&acpi_debugger.lock);
+ if (!acpi_debugger.ops) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ if (!try_module_get(acpi_debugger.owner)) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ func = acpi_debugger.ops->write_log;
+ owner = acpi_debugger.owner;
+ mutex_unlock(&acpi_debugger.lock);
+
+ ret = func(msg);
+
+ mutex_lock(&acpi_debugger.lock);
+ module_put(owner);
+err_lock:
+ mutex_unlock(&acpi_debugger.lock);
+ return ret;
+}
+
+ssize_t acpi_debugger_read_cmd(char *buffer, size_t buffer_length)
+{
+ ssize_t ret;
+ ssize_t (*func)(char *, size_t);
+ struct module *owner;
+
+ if (!acpi_debugger_initialized)
+ return -ENODEV;
+ mutex_lock(&acpi_debugger.lock);
+ if (!acpi_debugger.ops) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ if (!try_module_get(acpi_debugger.owner)) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ func = acpi_debugger.ops->read_cmd;
+ owner = acpi_debugger.owner;
+ mutex_unlock(&acpi_debugger.lock);
+
+ ret = func(buffer, buffer_length);
+
+ mutex_lock(&acpi_debugger.lock);
+ module_put(owner);
+err_lock:
+ mutex_unlock(&acpi_debugger.lock);
+ return ret;
+}
+
+int acpi_debugger_wait_command_ready(void)
+{
+ int ret;
+ int (*func)(bool, char *, size_t);
+ struct module *owner;
+
+ if (!acpi_debugger_initialized)
+ return -ENODEV;
+ mutex_lock(&acpi_debugger.lock);
+ if (!acpi_debugger.ops) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ if (!try_module_get(acpi_debugger.owner)) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ func = acpi_debugger.ops->wait_command_ready;
+ owner = acpi_debugger.owner;
+ mutex_unlock(&acpi_debugger.lock);
+
+ ret = func(acpi_gbl_method_executing,
+ acpi_gbl_db_line_buf, ACPI_DB_LINE_BUFFER_SIZE);
+
+ mutex_lock(&acpi_debugger.lock);
+ module_put(owner);
+err_lock:
+ mutex_unlock(&acpi_debugger.lock);
+ return ret;
+}
+
+int acpi_debugger_notify_command_complete(void)
+{
+ int ret;
+ int (*func)(void);
+ struct module *owner;
+
+ if (!acpi_debugger_initialized)
+ return -ENODEV;
+ mutex_lock(&acpi_debugger.lock);
+ if (!acpi_debugger.ops) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ if (!try_module_get(acpi_debugger.owner)) {
+ ret = -ENODEV;
+ goto err_lock;
+ }
+ func = acpi_debugger.ops->notify_command_complete;
+ owner = acpi_debugger.owner;
+ mutex_unlock(&acpi_debugger.lock);
+
+ ret = func();
+
+ mutex_lock(&acpi_debugger.lock);
+ module_put(owner);
+err_lock:
+ mutex_unlock(&acpi_debugger.lock);
+ return ret;
+}
+
+int __init acpi_debugger_init(void)
+{
+ mutex_init(&acpi_debugger.lock);
+ acpi_debugger_initialized = true;
+ return 0;
+}
+#endif
+
/*******************************************************************************
*
* FUNCTION: acpi_os_execute
@@ -1127,7 +1321,7 @@ acpi_status acpi_os_execute(acpi_execute_type type,
function, context));

if (type == OSL_DEBUGGER_MAIN_THREAD) {
- ret = acpi_aml_create_thread(function, context);
+ ret = acpi_debugger_create_thread(function, context);
if (ret) {
pr_err("Call to kthread_create() failed.\n");
status = AE_ERROR;
@@ -1377,7 +1571,7 @@ acpi_status acpi_os_get_line(char *buffer, u32 buffer_length, u32 *bytes_read)
#else
int ret;

- ret = acpi_aml_read_cmd(buffer, buffer_length);
+ ret = acpi_debugger_read_cmd(buffer, buffer_length);
if (ret < 0)
return AE_ERROR;
if (bytes_read)
@@ -1386,6 +1580,7 @@ acpi_status acpi_os_get_line(char *buffer, u32 buffer_length, u32 *bytes_read)

return AE_OK;
}
+EXPORT_SYMBOL(acpi_os_get_line);

#ifdef CONFIG_ACPI_MEMORY_ACCESS_CHECK_SUPPORT
u8 acpi_os_readable(void *pointer, acpi_size length)
@@ -1403,7 +1598,7 @@ acpi_status acpi_os_wait_command_ready(void)
{
int ret;

- ret = acpi_aml_wait_command_ready();
+ ret = acpi_debugger_wait_command_ready();
if (ret < 0)
return AE_ERROR;
return AE_OK;
@@ -1413,7 +1608,7 @@ acpi_status acpi_os_notify_command_complete(void)
{
int ret;

- ret = acpi_aml_notify_command_complete();
+ ret = acpi_debugger_notify_command_complete();
if (ret < 0)
return AE_ERROR;
return AE_OK;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 51a96a8..8f24e03 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -37,6 +37,8 @@
#include <linux/list.h>
#include <linux/mod_devicetable.h>
#include <linux/dynamic_debug.h>
+#include <linux/module.h>
+#include <linux/mutex.h>

#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
@@ -119,6 +121,75 @@ typedef int (*acpi_tbl_table_handler)(struct acpi_table_header *table);
typedef int (*acpi_tbl_entry_handler)(struct acpi_subtable_header *header,
const unsigned long end);

+/* Debugger support */
+
+struct acpi_debugger_ops {
+ int (*create_thread)(acpi_osd_exec_callback function, void *context);
+ ssize_t (*write_log)(const char *msg);
+ ssize_t (*read_cmd)(char *buffer, size_t length);
+ int (*wait_command_ready)(bool single_step, char *buffer, size_t length);
+ int (*notify_command_complete)(void);
+};
+
+struct acpi_debugger {
+ const struct acpi_debugger_ops *ops;
+ struct module *owner;
+ struct mutex lock;
+};
+
+#ifdef CONFIG_ACPI_DEBUGGER
+int __init acpi_debugger_init(void);
+int acpi_register_debugger(struct module *owner,
+ const struct acpi_debugger_ops *ops);
+void acpi_unregister_debugger(const struct acpi_debugger_ops *ops);
+int acpi_debugger_create_thread(acpi_osd_exec_callback function, void *context);
+ssize_t acpi_debugger_write_log(const char *msg);
+ssize_t acpi_debugger_read_cmd(char *buffer, size_t buffer_length);
+int acpi_debugger_wait_command_ready(void);
+int acpi_debugger_notify_command_complete(void);
+#else
+static inline int acpi_debugger_init(void)
+{
+ return -ENODEV;
+}
+
+static inline int acpi_register_debugger(struct module *owner,
+ const struct acpi_debugger_ops *ops)
+{
+ return -ENODEV;
+}
+
+static inline void acpi_unregister_debugger(const struct acpi_debugger_ops *ops)
+{
+}
+
+static inline int acpi_debugger_create_thread(acpi_osd_exec_callback function,
+ void *context)
+{
+ return -ENODEV;
+}
+
+static inline int acpi_debugger_write_log(const char *msg)
+{
+ return -ENODEV;
+}
+
+static inline int acpi_debugger_read_cmd(char *buffer, u32 buffer_length)
+{
+ return -ENODEV;
+}
+
+static inline int acpi_debugger_wait_command_ready(void)
+{
+ return -ENODEV;
+}
+
+static inline int acpi_debugger_notify_command_complete(void)
+{
+ return -ENODEV;
+}
+#endif
+
#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
void acpi_initrd_override(void *data, size_t size);
#else
diff --git a/include/linux/acpi_dbg.h b/include/linux/acpi_dbg.h
deleted file mode 100644
index 60f3887..0000000
--- a/include/linux/acpi_dbg.h
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * ACPI AML interfacing support
- *
- * Copyright (C) 2015, Intel Corporation
- * Authors: Lv Zheng <lv.zheng@xxxxxxxxx>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#ifndef _LINUX_ACPI_DBG_H
-#define _LINUX_ACPI_DBG_H
-
-#include <linux/acpi.h>
-
-#ifdef CONFIG_ACPI_DEBUGGER
-int __init acpi_aml_init(void);
-int acpi_aml_create_thread(acpi_osd_exec_callback function, void *context);
-ssize_t acpi_aml_write_log(const char *msg);
-ssize_t acpi_aml_read_cmd(char *buffer, size_t buffer_length);
-int acpi_aml_wait_command_ready(void);
-int acpi_aml_notify_command_complete(void);
-#else
-static int inline acpi_aml_init(void)
-{
- return 0;
-}
-static inline int acpi_aml_create_thread(acpi_osd_exec_callback function,
- void *context)
-{
- return -ENODEV;
-}
-static inline int acpi_aml_write_log(const char *msg)
-{
- return -ENODEV;
-}
-static inline int acpi_aml_read_cmd(char *buffer, u32 buffer_length)
-{
- return -ENODEV;
-}
-static inline int acpi_aml_wait_command_ready(void)
-{
- return -ENODEV;
-}
-static inline int acpi_aml_notify_command_complete(void)
-{
- return -ENODEV;
-}
-#endif
-
-#endif /* _LINUX_ACPI_DBG_H */
--
1.7.10

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