[PATCH 2/2] efi: implement mandatory locking for UEFI Runtime Services

[Matt Fleming]

On Wed, 02 Jul, at 12:10:02PM, Ard Biesheuvel wrote:
> According to section 7.1 of the UEFI spec, Runtime Services are not fully
> reentrant, and there are particular combinations of calls that need to be
> serialized.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> ---
>  drivers/firmware/efi/runtime-wrappers.c | 109 +++++++++++++++++++++++++++++---
>  1 file changed, 99 insertions(+), 10 deletions(-)

Ard, what's going on with this one? I didn't see it resubmitted along
with v3 of "efi/arm64: handle missing virtual mapping for UEFI System
Table".

Note that we already have a lock to serialize access to the UEFI
variable services in the form of __efivars->lock, see
drivers/firmware/efi/vars.c. It's a spinlock because of the context we
may need to create variables in from efi_pstore_write().

-- 
Matt Fleming, Intel Open Source Technology Center