[U-Boot] [RFC 0/6] efi_loader: support runtime variable access via cache
xypron.glpk at gmx.de
Wed Jun 5 10:34:05 UTC 2019
On 6/5/19 6:21 AM, AKASHI Takahiro wrote:
> EBBR v1.0 section 2.5.3 says
> Even when SetVariable() is not supported during runtime services,
> firmware should cache variable names and values in EfiRuntimeServicesData
> memory so that GetVariable() and GetNextVeriableName() can behave as
> This is an experimental patch set and the aim is to enable this feature.
thanks a lot for all the effort you put in this.
Reusing parts of env is a valid possibility but I am not sure if this is
the right approach for something that has to work at runtime.
I will need some time to layout my ideas of the design. Unfortunately I
am on a sea kayaking trip this weekend. So I may need until June 16th
for a thorough suggestion.
I have already picked the trivial patches from this patch series and
will put them into the next pull request.
> Cache buffer is in the same format as U-Boot environment hash table,
> but we cannot use functions in hashtable.c partly because most of U-Boot
> code are not available at UEFI runtime and partly because entries in
> a table are allocated by malloc(), which are again not available
> at UEFI runtime. It is quite painful to modify exiting U-Boot code
> so as to make it executable at UEFI runtime.
> So I implemented a limited version of hsearch_r(). This may be
> a discussion. Given that there are not so many UEFI variables,
> we may want to use a simpler table format for caching.
> Known issues:
> * Currently I test this feature with a test which is temporarily embedded
> in ExitBootServices.
> * After SetVirtualAddressMap, it won't work (TODO).
> ConvertPointer was implemented here just for this future work.
> * So how can we test the feature?
> We can't use "printenv" command as its relocation won't take place.
> * I see some Travis CI errors.
> This is probably due to no storage configured for UEFI variables.
> Patch#1 to #4 are preparatory patches.
> Patch#5 is mainly for testing.
> Patch#6 is core part of this patch set.
> AKASHI Takahiro (5):
> efi_loader: runtime: make SetVirtualAddressMap configurable
> efi: add RuntimeServicesSupported variable
> efi_loader: support convert_pointer at runtime
> cmd: efidebug: add "boot exit" sub-command
> efi_loader: variable: support runtime variable access via cache
> Alexander Graf (1):
> efi_loader: Patch non-runtime code out at ExitBootServices already
> cmd/efidebug.c | 63 ++++
> include/efi_api.h | 15 +
> include/efi_loader.h | 22 ++
> lib/efi_loader/Kconfig | 24 ++
> lib/efi_loader/efi_boottime.c | 11 +-
> lib/efi_loader/efi_runtime.c | 155 ++++++++--
> lib/efi_loader/efi_setup.c | 5 +
> lib/efi_loader/efi_variable.c | 467 +++++++++++++++++++++++++++++
> test/py/tests/test_efi_selftest.py | 4 +-
> 9 files changed, 735 insertions(+), 31 deletions(-)
More information about the U-Boot