6.1-stable review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan+linaro@kernel.org
commit bad267f9e18f8e9e628abd1811d2899b1735a4e1 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 --- drivers/firmware/efi/efi.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)
--- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -185,8 +185,27 @@ static const struct attribute_group efi_ static struct efivars generic_efivars; static struct efivar_operations generic_ops;
+static bool generic_ops_supported(void) +{ + unsigned long name_size; + efi_status_t status; + efi_char16_t name; + efi_guid_t guid; + + name_size = sizeof(name); + + status = efi.get_next_variable(&name_size, &name, &guid); + if (status == EFI_UNSUPPORTED) + return false; + + return true; +} + static int generic_ops_register(void) { + if (!generic_ops_supported()) + return 0; + generic_ops.get_variable = efi.get_variable; generic_ops.get_next_variable = efi.get_next_variable; generic_ops.query_variable_store = efi_query_variable_store; @@ -200,6 +219,9 @@ static int generic_ops_register(void)
static void generic_ops_unregister(void) { + if (!generic_ops.get_variable) + return; + efivars_unregister(&generic_efivars); }