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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 12:43:55 +08:00
linux-next/drivers/firmware
Matt Fleming 60b4dc7720 efi: Delete the in_nmi() conditional runtime locking
commit 5dc3826d9f08 ("efi: Implement mandatory locking for UEFI Runtime
Services") implemented some conditional locking when accessing variable
runtime services that Ingo described as "pretty disgusting".

The intention with the !efi_in_nmi() checks was to avoid live-locks when
trying to write pstore crash data into an EFI variable. Such lockless
accesses are allowed according to the UEFI specification when we're in a
"non-recoverable" state, but whether or not things are implemented
correctly in actual firmware implementations remains an unanswered
question, and so it would seem sensible to avoid doing any kind of
unsynchronized variable accesses.

Furthermore, the efi_in_nmi() tests are inadequate because they don't
account for the case where we call EFI variable services from panic or
oops callbacks and aren't executing in NMI context. In other words,
live-locking is still possible.

Let's just remove the conditional locking altogether. Now we've got the
->set_variable_nonblocking() EFI variable operation we can abort if the
runtime lock is already held. Aborting is by far the safest option.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2014-10-03 18:41:03 +01:00
..
efi efi: Delete the in_nmi() conditional runtime locking 2014-10-03 18:41:03 +01:00
google firmware: google memconsole driver fixes 2014-02-15 11:30:28 -08:00
dcdbas.c initconst: Fix initconst mistake in dcdbas 2014-02-13 18:14:54 -08:00
dcdbas.h dcdbas: export functionality for use in other drivers 2009-01-08 08:31:12 -08:00
dell_rbu.c sysfs: add struct file* to bin_attr callbacks 2010-05-21 09:37:31 -07:00
dmi_scan.c firmware/dmi_scan: generalize for use by other archs 2014-01-23 16:36:57 -08:00
dmi-id.c dmi-id: fix a memory leak in dmi_id_init error path 2010-08-05 13:53:34 -07:00
dmi-sysfs.c firmware: dmi-sysfs: Remove "dmi" directory on module exit 2013-12-08 18:23:42 -08:00
edd.c [SCSI] edd: Treat "XPRS" host bus type the same as "PCI" 2011-10-31 13:26:19 +04:00
iscsi_ibft_find.c efi: Make 'efi_enabled' a function to query EFI facilities 2013-01-30 11:51:59 -08:00
iscsi_ibft.c iscsi_ibft: Fix finding Broadcom specific ibft sign 2014-05-13 14:54:14 -04:00
Kconfig ACPI and power management updates for 3.14-rc1 2014-01-24 15:51:02 -08:00
Makefile x86/efi: Don't select EFI from certain special ACPI drivers 2013-12-19 21:32:46 +01:00
memmap.c drivers/firmware/memmap.c: don't allocate firmware_map_entry of same memory range 2014-08-06 18:01:20 -07:00
pcdp.c pcdp: use early_ioremap/early_iounmap to access pcdp table 2012-07-30 17:25:11 -07:00
pcdp.h Update broken web addresses in the kernel. 2010-10-18 11:03:14 +02:00