From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B37D1C43603 for ; Fri, 6 Dec 2019 22:14:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 86FAE206DB for ; Fri, 6 Dec 2019 22:14:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="c1Wx0pmg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726801AbfLFWO1 (ORCPT ); Fri, 6 Dec 2019 17:14:27 -0500 Received: from mail-qv1-f74.google.com ([209.85.219.74]:36402 "EHLO mail-qv1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726755AbfLFWOZ (ORCPT ); Fri, 6 Dec 2019 17:14:25 -0500 Received: by mail-qv1-f74.google.com with SMTP id r8so764467qvp.3 for ; Fri, 06 Dec 2019 14:14:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=FhYYEjTDkPuKHbZnKePlOaf9pf8CUWO3nD3sOS+po+M=; b=c1Wx0pmgZzJDLcr5nKIxS6pdb72MNBZXygUHxUgHfIREUjivSfJmFNkd4nH821+c7c XdMpdHUqSUmAmYnv/wYcSmRCYqJtUh+jdTQ3/0TYFxbvGCg3KubysunPGfqG0BjN6R5p FZYsTRty1KKiwCF3GFPmHDSfqSVDKBB9Dl9Svv8Esh85iZQ6Gp8IldBOuKDVG0NAYrct KCNN1c4Jt5Qnd9QE5BIqwUiELeUVYdQWv32ArtiqQbBLSzZpaS8483/PTd49tfr3IpbZ ZlBwyqxJM8pdiJ2dTz9waDv/2F+kWZdAUGGPKaihus1bQ20pRuQajRsHhJifC3dGS/Vz k2Wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=FhYYEjTDkPuKHbZnKePlOaf9pf8CUWO3nD3sOS+po+M=; b=N2cUY7Wp//m09h+MzwlnHTL0hygXJnpMpx2DJNKtCdwhe/KnKpdsUWfZFoPsvOq5I8 JXUb/T/rlPkMwFWZTSUZCnL9KsZ6xG8eWfNutvZ66H+GeeRkLyOG3WQMUqafrmkseSaZ SmreTujOvkPQBOYA6B6+USHCmJ/2BZYe0W/DUMc524P+i5/hUSiH6+XwEKKsn2tyfTif 6vmratKmnrje/S7fIvwrOKO740mF83DvjGakcsc3JuQGwE5/zPYI4ZTMlRHuYOqZ5L3s qIE3VqYobuJ6opFDj55QAT7rIQohvvD6svZRmkqxHd38L2WX430npdAPTKrcQ8KBuIyB GMlg== X-Gm-Message-State: APjAAAVg24zoLLZfHWk3wFt9a/J/t9N/Ckzw9jAUTIkyaSCwre7xvnvJ yYNrBcqD/LMsacFN06TqnAVpur6t02yijg/7va0= X-Google-Smtp-Source: APXvYqwZLBeooXOHcOO29WvEdpgbxookvNvj944sJ15kbZCCqA2Ea8mnulB5DEVBZW8wLWpSg85W/yQRRXH7nkmyS6o= X-Received: by 2002:ac8:2201:: with SMTP id o1mr15071384qto.247.1575670464028; Fri, 06 Dec 2019 14:14:24 -0800 (PST) Date: Fri, 6 Dec 2019 14:13:47 -0800 In-Reply-To: <20191206221351.38241-1-samitolvanen@google.com> Message-Id: <20191206221351.38241-12-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191206221351.38241-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.393.g34dc348eaf-goog Subject: [PATCH v6 11/15] arm64: efi: restore x18 if it was corrupted From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland Cc: Dave Martin , Kees Cook , Laura Abbott , Marc Zyngier , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we detect a corrupted x18 and SCS is enabled, restore the register before jumping back to instrumented code. This is safe, because the wrapper is called with preemption disabled and a separate shadow stack is used for interrupt handling. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- arch/arm64/kernel/efi-rt-wrapper.S | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S index 3fc71106cb2b..62f0260f5c17 100644 --- a/arch/arm64/kernel/efi-rt-wrapper.S +++ b/arch/arm64/kernel/efi-rt-wrapper.S @@ -34,5 +34,14 @@ ENTRY(__efi_rt_asm_wrapper) ldp x29, x30, [sp], #32 b.ne 0f ret -0: b efi_handle_corrupted_x18 // tail call +0: +#ifdef CONFIG_SHADOW_CALL_STACK + /* + * Restore x18 before returning to instrumented code. This is + * safe because the wrapper is called with preemption disabled and + * a separate shadow stack is used for interrupts. + */ + mov x18, x2 +#endif + b efi_handle_corrupted_x18 // tail call ENDPROC(__efi_rt_asm_wrapper) -- 2.24.0.393.g34dc348eaf-goog From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9CFE3C43603 for ; Fri, 6 Dec 2019 22:16:53 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5AF52206DB for ; Fri, 6 Dec 2019 22:16:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="k4kym2/c"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="c1Wx0pmg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5AF52206DB Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:From:Subject:References:Mime-Version :Message-Id:In-Reply-To:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=zo1UZkjVlNrrElhcRf/mUeyojspUB6NRjHXZPAwGEF8=; b=k4kym2/cOsx7nO /Z1ajQ2brw89bB16u5JRI1eBXOyyFzz8knnvgzGloVuR4JQ+Nk7lLwdbtB+EvF5zQqwkeaMSyEUwd 269lYzcqQlFKTHk8GMd4UJg5juDgvizryX8P0zgK6Q1UxoQQFZZ+GvH7l7nDmRvWxuPXtzLw47mnu sw3Bz7tVavIVUJasiXJVFmj7UT/BJWKby44Pu+ypK161F8NufWd5k18cNDn1V4AMm7l60UrkdwCeJ e/NnGCeaLwaqe1UL6Lq/g03ptSjxN5MV4JftAny7ILzwJePedVg790+GIvKHnEl+8aswMaeR3Q4WH SzUJoSLPekgQ3zRlKzyQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1idLu7-0001mi-VK; Fri, 06 Dec 2019 22:16:52 +0000 Received: from mail-qv1-xf4a.google.com ([2607:f8b0:4864:20::f4a]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1idLrm-0006nK-JM for linux-arm-kernel@lists.infradead.org; Fri, 06 Dec 2019 22:14:31 +0000 Received: by mail-qv1-xf4a.google.com with SMTP id q17so724891qvo.23 for ; Fri, 06 Dec 2019 14:14:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=FhYYEjTDkPuKHbZnKePlOaf9pf8CUWO3nD3sOS+po+M=; b=c1Wx0pmgZzJDLcr5nKIxS6pdb72MNBZXygUHxUgHfIREUjivSfJmFNkd4nH821+c7c XdMpdHUqSUmAmYnv/wYcSmRCYqJtUh+jdTQ3/0TYFxbvGCg3KubysunPGfqG0BjN6R5p FZYsTRty1KKiwCF3GFPmHDSfqSVDKBB9Dl9Svv8Esh85iZQ6Gp8IldBOuKDVG0NAYrct KCNN1c4Jt5Qnd9QE5BIqwUiELeUVYdQWv32ArtiqQbBLSzZpaS8483/PTd49tfr3IpbZ ZlBwyqxJM8pdiJ2dTz9waDv/2F+kWZdAUGGPKaihus1bQ20pRuQajRsHhJifC3dGS/Vz k2Wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=FhYYEjTDkPuKHbZnKePlOaf9pf8CUWO3nD3sOS+po+M=; b=Jkzi8arFKRlTYyUyv1P3mCTnXzsZNWTFaNjMBnaWyZNTA87BLM6rbVae2B0T6eb5Ri h70+yUNBfcTHvwP+bnL3AM3mIeFcowgk56a/320eAlWxtdz2DspLcgdMt98FBCOgPouF OlpsFZO0QqmZofwS0t9A5+T677i0aL3jFKGO5o5huqCwnW/NryC7uwOL2npBu3hIChEX RoHWBwBx5zV5PJmYPyaqQJBruTI+vkZWPlE3EQCb38B45VMJ0pYvGljB4n3OFNN0dK87 w/+8YSP74feSSw1JH/4VpAnR40nJqUSVddlhibx2V06X3/URH3xnmdMZ1RRp40eHJgXc jbww== X-Gm-Message-State: APjAAAXKnHmsRwrzDpXZ4YocYpuT7uQZgCz0YXjnD+O3FNRqmAt3Pifv GeM90RBRP5YkufE86GOMDcnMFHKJMck5nEup9AY= X-Google-Smtp-Source: APXvYqwZLBeooXOHcOO29WvEdpgbxookvNvj944sJ15kbZCCqA2Ea8mnulB5DEVBZW8wLWpSg85W/yQRRXH7nkmyS6o= X-Received: by 2002:ac8:2201:: with SMTP id o1mr15071384qto.247.1575670464028; Fri, 06 Dec 2019 14:14:24 -0800 (PST) Date: Fri, 6 Dec 2019 14:13:47 -0800 In-Reply-To: <20191206221351.38241-1-samitolvanen@google.com> Message-Id: <20191206221351.38241-12-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191206221351.38241-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.393.g34dc348eaf-goog Subject: [PATCH v6 11/15] arm64: efi: restore x18 if it was corrupted From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191206_141426_673779_AEDC41F2 X-CRM114-Status: UNSURE ( 9.76 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kees Cook , Jann Horn , Masahiro Yamada , Marc Zyngier , kernel-hardening@lists.openwall.com, Nick Desaulniers , linux-kernel@vger.kernel.org, Miguel Ojeda , clang-built-linux@googlegroups.com, Sami Tolvanen , Laura Abbott , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org If we detect a corrupted x18 and SCS is enabled, restore the register before jumping back to instrumented code. This is safe, because the wrapper is called with preemption disabled and a separate shadow stack is used for interrupt handling. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- arch/arm64/kernel/efi-rt-wrapper.S | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S index 3fc71106cb2b..62f0260f5c17 100644 --- a/arch/arm64/kernel/efi-rt-wrapper.S +++ b/arch/arm64/kernel/efi-rt-wrapper.S @@ -34,5 +34,14 @@ ENTRY(__efi_rt_asm_wrapper) ldp x29, x30, [sp], #32 b.ne 0f ret -0: b efi_handle_corrupted_x18 // tail call +0: +#ifdef CONFIG_SHADOW_CALL_STACK + /* + * Restore x18 before returning to instrumented code. This is + * safe because the wrapper is called with preemption disabled and + * a separate shadow stack is used for interrupts. + */ + mov x18, x2 +#endif + b efi_handle_corrupted_x18 // tail call ENDPROC(__efi_rt_asm_wrapper) -- 2.24.0.393.g34dc348eaf-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E31AEC43603 for ; Fri, 6 Dec 2019 22:16:02 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 3B7BC21835 for ; Fri, 6 Dec 2019 22:16:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="c1Wx0pmg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B7BC21835 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17483-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 22215 invoked by uid 550); 6 Dec 2019 22:14:36 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 22122 invoked from network); 6 Dec 2019 22:14:36 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=FhYYEjTDkPuKHbZnKePlOaf9pf8CUWO3nD3sOS+po+M=; b=c1Wx0pmgZzJDLcr5nKIxS6pdb72MNBZXygUHxUgHfIREUjivSfJmFNkd4nH821+c7c XdMpdHUqSUmAmYnv/wYcSmRCYqJtUh+jdTQ3/0TYFxbvGCg3KubysunPGfqG0BjN6R5p FZYsTRty1KKiwCF3GFPmHDSfqSVDKBB9Dl9Svv8Esh85iZQ6Gp8IldBOuKDVG0NAYrct KCNN1c4Jt5Qnd9QE5BIqwUiELeUVYdQWv32ArtiqQbBLSzZpaS8483/PTd49tfr3IpbZ ZlBwyqxJM8pdiJ2dTz9waDv/2F+kWZdAUGGPKaihus1bQ20pRuQajRsHhJifC3dGS/Vz k2Wg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=FhYYEjTDkPuKHbZnKePlOaf9pf8CUWO3nD3sOS+po+M=; b=RX7lHrhghduTDpLUyB0ZK43Fg0nyna1Al3sMTBxT9SGGA4GWxxTCDMolWK4BaOJeeT i0uHoj5QiC12kJeVcEWevT6W/0ViVOKSdZl6HRQKvyhgIRXKn7eFhiHMu0PYy3lZU0yk YNY5xLNzx/IvK1tMgcZGJMD/LpsL3lBakthc2QkCHifKfzGh9VRjIR794w+kmQIV1lp/ wUfdFZwhMsDJaDErUIj2Orz6KJ1dDBkT5DCHoaFxQnrQnp6nas5QbRR1I+EPSDb3eUCL +HXVp0MElzNgL5cAThHvXJqM+W9opB5xbENiy9eEwrbX6FdNi1+UygX6ifFcFfxnNpj9 Xt2g== X-Gm-Message-State: APjAAAU0ow8IsbrWdaTkcGMiqdJ5A2Rh1Jq8W1dDGBJ8dtulsJ5gLIep nbkLOe30VPfiECG3fTFtr1EAFyrXqMaaQ8gnSck= X-Google-Smtp-Source: APXvYqwZLBeooXOHcOO29WvEdpgbxookvNvj944sJ15kbZCCqA2Ea8mnulB5DEVBZW8wLWpSg85W/yQRRXH7nkmyS6o= X-Received: by 2002:ac8:2201:: with SMTP id o1mr15071384qto.247.1575670464028; Fri, 06 Dec 2019 14:14:24 -0800 (PST) Date: Fri, 6 Dec 2019 14:13:47 -0800 In-Reply-To: <20191206221351.38241-1-samitolvanen@google.com> Message-Id: <20191206221351.38241-12-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191206221351.38241-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.393.g34dc348eaf-goog Subject: [PATCH v6 11/15] arm64: efi: restore x18 if it was corrupted From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland Cc: Dave Martin , Kees Cook , Laura Abbott , Marc Zyngier , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" If we detect a corrupted x18 and SCS is enabled, restore the register before jumping back to instrumented code. This is safe, because the wrapper is called with preemption disabled and a separate shadow stack is used for interrupt handling. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- arch/arm64/kernel/efi-rt-wrapper.S | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S index 3fc71106cb2b..62f0260f5c17 100644 --- a/arch/arm64/kernel/efi-rt-wrapper.S +++ b/arch/arm64/kernel/efi-rt-wrapper.S @@ -34,5 +34,14 @@ ENTRY(__efi_rt_asm_wrapper) ldp x29, x30, [sp], #32 b.ne 0f ret -0: b efi_handle_corrupted_x18 // tail call +0: +#ifdef CONFIG_SHADOW_CALL_STACK + /* + * Restore x18 before returning to instrumented code. This is + * safe because the wrapper is called with preemption disabled and + * a separate shadow stack is used for interrupts. + */ + mov x18, x2 +#endif + b efi_handle_corrupted_x18 // tail call ENDPROC(__efi_rt_asm_wrapper) -- 2.24.0.393.g34dc348eaf-goog