The patch titled
acpi ec_sys: be more cautious about ec write access
has been added to the -mm tree. Its filename is
acpi-ec_sys-be-more-cautious-about-ec-write-access.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: acpi ec_sys: be more cautious about ec write access
From: Thomas Renninger <trenn@xxxxxxx>
- Set Kconfig option default n
- Only allow root to read/write io file (sever bug!)
- Introduce write support module param -> default off
- Properly clean up if any debugfs files cannot be created
Signed-off-by: Thomas Renninger <trenn@xxxxxxx>
Cc: Matthew Garrett <mjg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/acpi/Kconfig | 11 ++++++++---
drivers/acpi/ec_sys.c | 30 +++++++++++++++++++++++-------
2 files changed, 31 insertions(+), 10 deletions(-)
diff -puN drivers/acpi/Kconfig~acpi-ec_sys-be-more-cautious-about-ec-write-access drivers/acpi/Kconfig
--- a/drivers/acpi/Kconfig~acpi-ec_sys-be-more-cautious-about-ec-write-access
+++ a/drivers/acpi/Kconfig
@@ -106,14 +106,19 @@ config ACPI_SYSFS_POWER
config ACPI_EC_DEBUGFS
tristate "EC read/write access through /sys/kernel/debug/ec"
- default y
+ default n
help
Say N to disable Embedded Controller /sys/kernel/debug interface
+ Be aware that using this interface can confuse your Embedded
+ Controller in a way that a normal reboot is not enough. You then
+ have to power of your system, and remove the laptop battery for
+ some seconds.
An Embedded Controller typically is available on laptops and reads
sensor values like battery state and temperature.
- The kernel access the EC through ACPI parsed code provided by BIOS
- tables.
+ The kernel accesses the EC through ACPI parsed code provided by BIOS
+ tables. This option allows to access the EC directly without ACPI
+ code being involved.
Thus this option is a debug option that helps to write ACPI drivers
and can be used to identify ACPI code or EC firmware bugs.
diff -puN drivers/acpi/ec_sys.c~acpi-ec_sys-be-more-cautious-about-ec-write-access drivers/acpi/ec_sys.c
--- a/drivers/acpi/ec_sys.c~acpi-ec_sys-be-more-cautious-about-ec-write-access
+++ a/drivers/acpi/ec_sys.c
@@ -17,6 +17,11 @@ MODULE_AUTHOR("Thomas Renninger <trenn@s
MODULE_DESCRIPTION("ACPI EC sysfs access driver");
MODULE_LICENSE("GPL");
+static bool write_support;
+module_param(write_support, bool, 0644);
+MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may "
+ "be needed.");
+
#define EC_SPACE_SIZE 256
struct sysdev_class acpi_ec_sysdev_class = {
@@ -102,6 +107,7 @@ int acpi_ec_add_debugfs(struct acpi_ec *
{
struct dentry *dev_dir;
char name[64];
+
if (ec_device_count == 0) {
acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
if (!acpi_ec_debugfs_dir)
@@ -111,17 +117,27 @@ int acpi_ec_add_debugfs(struct acpi_ec *
sprintf(name, "ec%u", ec_device_count);
dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
if (!dev_dir) {
- if (ec_device_count == 0)
- debugfs_remove_recursive(acpi_ec_debugfs_dir);
- /* TBD: Proper cleanup for multiple ECs */
+ if (ec_device_count != 0)
+ goto error;
return -ENOMEM;
}
- debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe);
- debugfs_create_bool("use_global_lock", 0444, dev_dir,
- (u32 *)&first_ec->global_lock);
- debugfs_create_file("io", 0666, dev_dir, ec, &acpi_ec_io_ops);
+ if (!debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe))
+ goto error;
+ if (!debugfs_create_bool("use_global_lock", 0444, dev_dir,
+ (u32 *)&first_ec->global_lock))
+ goto error;
+
+ if (!write_support)
+ acpi_ec_io_ops.write = NULL;
+ if (!debugfs_create_file("io", 0600, dev_dir, ec, &acpi_ec_io_ops))
+ goto error;
+
return 0;
+
+error:
+ debugfs_remove_recursive(acpi_ec_debugfs_dir);
+ return -ENOMEM;
}
static int __init acpi_ec_sys_init(void)
_
Patches currently in -mm which might be from trenn@xxxxxxx are
origin.patch
linux-next.patch
acpi-ec-fix-possible-double-io-port-registration.patch
acpi-ec_sys-be-more-cautious-about-ec-write-access.patch
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