kernel/linux.git/drivers/acpi/sysfs.c, branch v4.11.5

ACPI / sysfs: fix acpi_get_table() leak / acpi-sysfs denial of service

2017-06-07T10:10:07+00:00

commit 0de0e198bc7191a0e46cf71f66fec4d07ca91396 upstream. Reading an ACPI table through the /sys/firmware/acpi/tables interface more than 65,536 times leads to the following log message: ACPI Error: Table ffff88033595eaa8, Validation count is zero after increment (20170119/tbutils-423) ...and the table being unavailable until the next reboot. Add the missing acpi_put_table() so the table ->validation_count is decremented after each read. Reported-by: Anush Seetharaman Fixes: 174cc7187e6f "ACPICA: Tables: Back port acpi_get_table_with_size() ..." Signed-off-by: Dan Williams Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

ACPI / sysfs: Provide quirk mechanism to prevent GPE flooding

2016-12-26T22:16:39+00:00

Sometimes, the users may require a quirk to be provided from ACPI subsystem core to prevent a GPE from flooding. Normally, if a GPE cannot be dispatched, ACPICA core automatically prevents the GPE from firing. But there are cases the GPE is dispatched by _Lxx/_Exx provided via AML table, and OSPM is lacking of the knowledge to get _Lxx/_Exx correctly executed to handle the GPE, thus the GPE flooding may still occur. The existing quirk mechanism can be enabled/disabled using the following commands to prevent such kind of GPE flooding during runtime: # echo mask > /sys/firmware/acpi/interrupts/gpe00 # echo unmask > /sys/firmware/acpi/interrupts/gpe00 To avoid GPE flooding during boot, we need a boot stage mechanism. This patch provides such a boot stage quirk mechanism to stop this kind of GPE flooding. This patch doesn't fix any feature gap but since the new feature gaps could be found in the future endlessly, and can disappear if the feature gaps are filled, providing a boot parameter rather than a DMI table should suffice. Link: https://bugzilla.kernel.org/show_bug.cgi?id=53071 Link: https://bugzilla.kernel.org/show_bug.cgi?id=117481 Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/887793 Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki

ACPI / sysfs: Update sysfs signature handling code

2016-09-16T23:12:34+00:00

This patch cleans up sysfs table signature handling code: 1. Convert the signature handling code to use the ACPICA APIs to benefit from the future improvements of the APIs. 2. Add 'filename' attribute in order to handle both BE/LE name tags. 3. Add instance check in order to avoid the possible buffer overflow related to the table file name. Signed-off-by: Lv Zheng [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki

ACPI / sysfs: Fix an issue for LoadTable opcode

2016-09-16T23:10:43+00:00

OEM tables can be installed via RSDT/XSDT, in this case, they have already been created under /sys/firmware/acpi/tables. For this kind of tables, normally LoadTable opcode will be executed to load them. If LoadTable opcode is executed after acpi_sysfs_init(), acpi_sysfs_table_handler() will be invoked, thus a redundant table file will be created under /sys/firmware/acpi/tables/dynamic. Then running "acpidump" on such platform results in an error, complaining blank empty table (see Link 1 below). The bug can be reproduced by customizing an OEM1 table, allowing it to be overridden via 'table_sigs' (drivers/acpi/tables.c), adding the following code to the customized DSDT to load it: Name (OEMH, Zero) Name (OEMF, One) If (LEqual (OEMF, One)) { Store (LoadTable ("OEM1", "Intel", "Test"), OEMH) Store (Zero, OEMF) } In order to make sure that the OEM1 table is installed after acpi_sysfs_init(), acpi_sysfs_init() can be moved before invoking acpi_load_tables(). Then the following command execution result can be seen: # acpidump > acpidump.txt Could not read table header: /sysfs/firmware/acpi/tables/dynamic/OEM12 Could not get ACPI table at index 17, AE_BAD_HEADER Link: https://bugzilla.kernel.org/show_bug.cgi?id=150841 # [1] Link: https://github.com/acpica/acpica/commit/ed6a5fbc Reported-by: Jason Voelz Reported-by: Francisco Leoner Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki

ACPI / sysfs: Use new GPE masking mechanism in GPE interface

2016-08-17T00:10:44+00:00

Now GPE can be masked via the new acpi_mask_gpe() API and this patch modifies /sys/firmware/acpi/interrupts/gpexx to use this new facility. Writes "mask/unmask" to this file now invokes acpi_mask_gpe(). Reads from this file now returns new "EN/STS" when the corresponding GPE hardware register's EN/STS bits are flagged, and new "masked/unmasked" attribute to indicate the status of the masking mechanism. Signed-off-by: Lv Zheng [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki

ACPI: add support for ACPI reconfiguration notifiers

2016-07-08T19:52:35+00:00

Add support for ACPI reconfiguration notifiers to allow subsystems to react to changes in the ACPI tables that happen after the initial enumeration. This is similar with the way dynamic device tree notifications work. The reconfigure notifications supported for now are device add and device remove. Since ACPICA allows only one table notification handler, this patch makes the table notifier function generic and moves it out of the sysfs specific code. Signed-off-by: Octavian Purdila Reviewed-by: Mika Westerberg Signed-off-by: Rafael J. Wysocki

ACPI / sysfs: fix error code in get_status()

2016-05-05T13:28:58+00:00

The problem with ornamental, do-nothing gotos is that they lead to "forgot to set the error code" bugs. We should be returning -EINVAL here but we don't. It leads to an uninitalized variable in counter_show(): drivers/acpi/sysfs.c:603 counter_show() error: uninitialized symbol 'status'. Fixes: 1c8fce27e275 (ACPI: introduce drivers/acpi/sysfs.c) Signed-off-by: Dan Carpenter Signed-off-by: Rafael J. Wysocki

ACPI / sysfs: correctly check failing memory allocation

2015-10-26T03:57:27+00:00

Since kobject_create_and_add() can fail under memory pressure, its return value needs to be checked against NULL before passing it to sysfs_create_file(). Signed-off-by: Insu Yun [ rjw: Subject & changelog ] Signed-off-by: Rafael J. Wysocki

ACPI / sysfs: Add support to allow leading "\" missing in trace_method_name.

2015-08-07T00:42:22+00:00

Since _SB.PCI0 can be used as relative path from root and can be easily converted into internal trace_method_name format, we allow users to specify trace_method_name using relative paths from root. Note this is useful for grub2 for which users failed to pass "\" from the grub configuration file. Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki

ACPI / sysfs: Update method tracing facility.

2015-08-07T00:42:21+00:00

This patch updates the method tracing facility as the acpi_debug_trace() API has been updated to allow it to trace AML interpreter execution, the meanings and the usages of the API parameters are changed due to the updates. The new API: 1. Uses ACPI_TRACE_ENABLED flag to indicate the enabling of the tracer; 2. Allows tracer still can be enabled when method name is not specified so that the AML interpreter execution can be traced without knowing the method name, which is useful for kernel boot tracing; 3. Supports arbitrary full path name, it doesn't need to be a name related to an entrance of acpi_evaluate_object(). Note that the sysfs parameters are also updated so that when reading the attribute files, ACPICA internal settings are returned. In order to make the sysfs parameters (acpi.trace_state) available during boot, this patch adds code to bypass ACPICA semaphore/mutex invocations when acpi mutex utilities haven't been initialized. This patch doesn't update documentation of method tracing facility, it will be updated by further patches. Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki