/sys/firmware/acpi/hotplug/force_remove was presumably added to support
auto offlining in the past. This is, however, inherently dangerous for
some hotplugable resources like memory. The memory offlining fails when
the memory is still in use and cannot be dropped or migrated. If we
ignore the failure we are basically allowing for subtle memory
corruption or a crash.
We have actually noticed the later while hitting BUG() during the memory
hotremove (remove_memory):
ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
check_memblock_offlined_cb);
if (ret)
BUG();
it took us quite non-trivial time realize that the customer had
force_remove enabled. Even if the BUG was removed here and we could
propagate the error up the call chain it wouldn't help at all because
then we would hit a crash or a memory corruption later and harder to
debug. So force_remove is unfixable for the memory hotremove. We haven't
checked other hotplugable resources to be prone to a similar problems.
Remove the force_remove functionality because it is not fixable currently.
Keep the sysfs file and report an error if somebody tries to enable it.
Encourage users to report about the missing functionality and work with
them with an alternative solution.
Reviewed-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This fixes several spelling mistakes in the Documentation/ tree, which
are caught by checkpatch.pl's spell checking.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Modify the generic ACPI hotplug code to be able to check if devices
scheduled for hot-removal may be gracefully removed from the system
using the device offline/online mechanism introduced previously.
Namely, make acpi_scan_hot_remove() handling device hot-removal call
device_offline() for all physical companions of the ACPI device nodes
involved in the operation and check the results. If any of the
device_offline() calls fails, the function will not progress to the
removal phase (which cannot be aborted), unless its (new) force
argument is set (in case of a failing offline it will put the devices
offlined by it back online).
In support of 'forced' device hot-removal, add a new sysfs attribute
'force_remove' that will reside under /sys/firmware/acpi/hotplug/.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Introduce user space interface for manipulating hotplug profiles
associated with ACPI scan handlers.
The interface consists of sysfs directories under
/sys/firmware/acpi/hotplug/, one for each hotplug profile, containing
an attribute allowing user space to manipulate the enabled field of
the corresponding profile. Namely, switching the enabled attribute
from '0' to '1' will cause the common hotplug notify handler to be
installed for all ACPI namespace objects representing devices matching
the scan handler associated with the given hotplug profile (and
analogously for the converse switch).
Drivers willing to use the new user space interface should add their
ACPI scan handlers with the help of new funtion
acpi_scan_add_handler_with_hotplug().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Tested-by: Toshi Kani <toshi.kani@hp.com>
ACPI 5.0 adds the BGRT, a table that contains a pointer to the firmware
boot splash and associated metadata. This simple driver exposes it via
/sys/firmware/acpi in order to allow bootsplash applications to draw their
splash around the firmware image and reduce the number of jarring graphical
transitions during boot.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Introduce a new flag showing whether the event has an event handler/method.
For all the GPEs and Fixed Events,
1. ACPI_EVENT_FLAG_HANDLE is cleared, it's an "invalid" ACPI event.
2. Both ACPI_EVENT_FLAG_HANDLE and ACPI_EVENT_FLAG_DISABLE are set,
it's "disabled".
3. Both ACPI_EVENT_FLAG_HANDLE and ACPI_EVENT_FLAG_ENABLE are set,
it's "enabled".
4. Both ACPI_EVENT_FLAG_HANDLE and ACPI_EVENT_FLAG_WAKE_ENABLE are set,
it's "wake_enabled".
Among other things, this prevents incorrect reporting of ACPI events
as being "invalid" when it's really just (temporarily) "disabled".
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Len Brown <len.brown@intel.com>
Allow users to enable/disable/clear a specific & valid GPE/Fixed Event
in user space.
This is useful for debugging, especially for some
interrupt storm issues.
All wakeup GPEs are disabled and they can not be enabled at runtime,
and we mark them as invalid.
All GPEs that don't have a _Lxx/_Exx method are marked as invalid.
All Fixed Events that don't have an event handler are marked as invalid
and they can't be enabled until an event handler is registered.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Ling Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
See Documentation/ABI/testing/sysfs-firmware-acpi
Based-on-original-patch-by: Luming Yu <luming.yu@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
Michal Hocko