efi: verify that variable services are supported

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commit bad267f9e1 upstream.

Current Qualcomm UEFI firmware does not implement the variable services
but not all revisions clear the corresponding bits in the RT_PROP table
services mask and instead the corresponding calls return
EFI_UNSUPPORTED.

This leads to efi core registering the generic efivar ops even when the
variable services are not supported or when they are accessed through
some other interface (e.g. Google SMI or the upcoming Qualcomm SCM
implementation).

Instead of playing games with init call levels to make sure that the
custom implementations are registered after the generic one, make sure
that get_next_variable() is actually supported before registering the
generic ops.

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Johan Hovold 2023-01-19 17:42:54 +01:00 • committed by Greg Kroah-Hartman

parent 71c43b714f

commit a8901f331b

1 changed files with 22 additions and 0 deletions

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drivers/firmware/efi/efi.c

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