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author | Ard Biesheuvel <ardb@kernel.org> | 2020-07-08 13:01:57 +0300 |
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committer | Ard Biesheuvel <ardb@kernel.org> | 2020-07-09 10:14:29 +0300 |
commit | f88814cc2578c121e6edef686365036db72af0ed (patch) | |
tree | 6e26f83eb19d95e6791b0aab4ef931ef75bb3286 /drivers/firmware/efi/efi-pstore.c | |
parent | 3230d95cea0515a6acf3f5ff360663de4c40fd07 (diff) | |
download | linux-f88814cc2578c121e6edef686365036db72af0ed.tar.bz2 |
efi/efivars: Expose RT service availability via efivars abstraction
Commit
bf67fad19e493b ("efi: Use more granular check for availability for variable services")
introduced a check into the efivarfs, efi-pstore and other drivers that
aborts loading of the module if not all three variable runtime services
(GetVariable, SetVariable and GetNextVariable) are supported. However, this
results in efivarfs being unavailable entirely if only SetVariable support
is missing, which is only needed if you want to make any modifications.
Also, efi-pstore and the sysfs EFI variable interface could be backed by
another implementation of the 'efivars' abstraction, in which case it is
completely irrelevant which services are supported by the EFI firmware.
So make the generic 'efivars' abstraction dependent on the availibility of
the GetVariable and GetNextVariable EFI runtime services, and add a helper
'efivar_supports_writes()' to find out whether the currently active efivars
abstraction supports writes (and wire it up to the availability of
SetVariable for the generic one).
Then, use the efivar_supports_writes() helper to decide whether to permit
efivarfs to be mounted read-write, and whether to enable efi-pstore or the
sysfs EFI variable interface altogether.
Fixes: bf67fad19e493b ("efi: Use more granular check for availability for variable services")
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Diffstat (limited to 'drivers/firmware/efi/efi-pstore.c')
-rw-r--r-- | drivers/firmware/efi/efi-pstore.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c index c2f1d4e6630b..feb7fe6f2da7 100644 --- a/drivers/firmware/efi/efi-pstore.c +++ b/drivers/firmware/efi/efi-pstore.c @@ -356,10 +356,7 @@ static struct pstore_info efi_pstore_info = { static __init int efivars_pstore_init(void) { - if (!efi_rt_services_supported(EFI_RT_SUPPORTED_VARIABLE_SERVICES)) - return 0; - - if (!efivars_kobject()) + if (!efivars_kobject() || !efivar_supports_writes()) return 0; if (efivars_pstore_disable) |