linux/drivers/firmware
Matt Fleming e14ab23dde efivars: efivar_entry API
There isn't really a formal interface for dealing with EFI variables
or struct efivar_entry. Historically, this has led to various bits of
code directly accessing the generic EFI variable ops, which inherently
ties it to specific EFI variable operations instead of indirectly
using whatever ops were registered with register_efivars(). This lead
to the efivarfs code only working with the generic EFI variable ops
and not CONFIG_GOOGLE_SMI.

Encapsulate everything that needs to access '__efivars' inside an
efivar_entry_* API and use the new API in the pstore, sysfs and
efivarfs code.

Much of the efivars code had to be rewritten to use this new API. For
instance, it is now up to the users of the API to build the initial
list of EFI variables in their efivar_init() callback function. The
variable list needs to be passed to efivar_init() which allows us to
keep work arounds for things like implementation bugs in
GetNextVariable() in a central location.

Allowing users of the API to use a callback function to build the list
greatly benefits the efivarfs code which needs to allocate inodes and
dentries for every variable.  It previously did this in a racy way
because the code ran without holding the variable spinlock. Both the
sysfs and efivarfs code maintain their own lists which means the two
interfaces can be running simultaneously without interference, though
it should be noted that because no synchronisation is performed it is
very easy to create inconsistencies. efibootmgr doesn't currently use
efivarfs and users are likely to also require the old sysfs interface,
so it makes sense to allow both to be built.

Reviewed-by: Tom Gundersen <teg@jklm.no>
Tested-by: Tom Gundersen <teg@jklm.no>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Mike Waychison <mikew@google.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-04-17 13:23:59 +01:00
..
google efivars: efivar_entry API 2013-04-17 13:23:59 +01:00
dcdbas.c Drivers: misc: remove __dev* attributes. 2013-01-03 15:57:16 -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 dmi_scan: fix missing check for _DMI_ signature in smbios_present() 2013-03-08 15:05:34 -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: Fix unaligned memory accesses in dmi-sysfs 2011-02-25 16:10:03 -08:00
edd.c [SCSI] edd: Treat "XPRS" host bus type the same as "PCI" 2011-10-31 13:26:19 +04:00
efivars.c efivars: efivar_entry API 2013-04-17 13:23:59 +01:00
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 switch ->is_visible() to returning umode_t 2012-01-03 22:54:55 -05:00
Kconfig efivars: Add module parameter to disable use as a pstore backend 2013-03-21 12:43:46 +00:00
Makefile ASoC: Move SigmaDSP firmware loader to ASoC 2011-11-29 12:01:10 +00:00
memmap.c memory-hotplug: remove /sys/firmware/memmap/X sysfs 2013-02-23 17:50:12 -08:00
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