From nobody Sun Sep 14 18:21:53 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB5FAC004D4 for ; Thu, 19 Jan 2023 16:46:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229682AbjASQqP (ORCPT ); Thu, 19 Jan 2023 11:46:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230403AbjASQqE (ORCPT ); Thu, 19 Jan 2023 11:46:04 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 756998BAA2; Thu, 19 Jan 2023 08:45:51 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id C7B7ACE24F8; Thu, 19 Jan 2023 16:45:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E105C43392; Thu, 19 Jan 2023 16:45:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1674146748; bh=QeWwkHCkmPI6InIWABry3ht60PE2twa3Wx83EnocKUc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FcC3eOC0tK1JDm2vU5t6lG8N6tu2TTkZsEkQFINKv3WNnID1xUrnhqQa7j+fE2+eO LcdFhQp59mnpkqoWEGnz6PhnIH/Pg6NwhEDX7x3kj4AHY50PIe4zwX0LpS+WD+V/5J cwDq20s978Dr0himuRr1MO4WFz+zoObpD4Kinu4ZdJ1rDUhcwohVF99J00aZlaUHWT lAdsUpO2pS7hFAQTko8jDkFb2joMJ07UK8+jEeVo1m1033azICpEOXvSQaiwXi2shX DLK+9UsVAtYuOCeg4TWtEhoZF0yyCbbeDcOgI8Sya7pkc4vj0Daq03uym8g9IvcfYK UhqdEVTUPEutw== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1pIY3M-0007Mv-7w; Thu, 19 Jan 2023 17:46:16 +0100 From: Johan Hovold To: Ard Biesheuvel Cc: Matthew Garrett , Jeremy Kerr , Maximilian Luz , linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold Subject: [PATCH 3/4] efi: verify that variable services are supported Date: Thu, 19 Jan 2023 17:42:54 +0100 Message-Id: <20230119164255.28091-4-johan+linaro@kernel.org> X-Mailer: git-send-email 2.38.2 In-Reply-To: <20230119164255.28091-1-johan+linaro@kernel.org> References: <20230119164255.28091-1-johan+linaro@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 --- drivers/firmware/efi/efi.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index a7f1a32537f1..03ccc4e8d1fc 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -187,8 +187,27 @@ static const struct attribute_group efi_subsys_attr_gr= oup =3D { static struct efivars generic_efivars; static struct efivar_operations generic_ops; =20 +static bool generic_ops_supported(void) +{ + unsigned long name_size; + efi_status_t status; + efi_char16_t name; + efi_guid_t guid; + + name_size =3D sizeof(name); + + status =3D efi.get_next_variable(&name_size, &name, &guid); + if (status =3D=3D EFI_UNSUPPORTED) + return false; + + return true; +} + static int generic_ops_register(void) { + if (!generic_ops_supported()) + return 0; + generic_ops.get_variable =3D efi.get_variable; generic_ops.get_next_variable =3D efi.get_next_variable; generic_ops.query_variable_store =3D efi_query_variable_store; @@ -202,6 +221,9 @@ static int generic_ops_register(void) =20 static void generic_ops_unregister(void) { + if (!generic_ops.get_variable) + return; + efivars_unregister(&generic_efivars); } =20 --=20 2.38.2