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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55779C4321E for ; Mon, 7 Mar 2022 20:53:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245425AbiCGUye (ORCPT ); Mon, 7 Mar 2022 15:54:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245363AbiCGUyS (ORCPT ); Mon, 7 Mar 2022 15:54:18 -0500 Received: from gloria.sntech.de (gloria.sntech.de [185.11.138.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6087727FEC for ; Mon, 7 Mar 2022 12:53:22 -0800 (PST) Received: from ip5b412258.dynamic.kabel-deutschland.de ([91.65.34.88] helo=phil.lan) by gloria.sntech.de with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nRKM3-0002DJ-Qu; Mon, 07 Mar 2022 21:53:19 +0100 From: Heiko Stuebner To: palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, wefu@redhat.com, liush@allwinnertech.com, guoren@kernel.org, atishp@atishpatra.org, anup@brainfault.org, drew@beagleboard.org, hch@lst.de, arnd@arndb.de, wens@csie.org, maxime@cerno.tech, gfavor@ventanamicro.com, andrea.mondelli@huawei.com, behrensj@mit.edu, xinhaoqu@huawei.com, mick@ics.forth.gr, allen.baum@esperantotech.com, jscheid@ventanamicro.com, rtrauben@gmail.com, samuel@sholland.org, cmuellner@linux.com, philipp.tomsich@vrull.eu, Heiko Stuebner Subject: [PATCH v7 07/13] riscv: prevent compressed instructions in alternatives Date: Mon, 7 Mar 2022 21:53:04 +0100 Message-Id: <20220307205310.1905628-8-heiko@sntech.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220307205310.1905628-1-heiko@sntech.de> References: <20220307205310.1905628-1-heiko@sntech.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Instructions are opportunistically compressed by the RISC-V assembler when possible, but in alternatives-blocks both the old and new content need to be the same size, so having the toolchain do somewhat random optimizations will cause strange side-effects like "attempt to move .org backwards" compile-time errors. Already a simple "and" used in alternatives assembly will cause these mismatched code sizes. So prevent compressed instructions to be generated in alternatives- code and use option-push and -pop to only limit this to the relevant code blocks Signed-off-by: Heiko Stuebner --- arch/riscv/include/asm/alternative-macros.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h index c0fb11fad631..3a52884bf23d 100644 --- a/arch/riscv/include/asm/alternative-macros.h +++ b/arch/riscv/include/asm/alternative-macros.h @@ -19,7 +19,10 @@ .popsection .subsection 1 888 : + .option push + .option norvc \new_c + .option pop 889 : .previous .org . - (889b - 888b) + (887b - 886b) @@ -29,7 +32,10 @@ .macro __ALTERNATIVE_CFG old_c, new_c, vendor_id, errata_id, enable 886 : + .option push + .option norvc \old_c + .option pop 887 : ALT_NEW_CONTENT \vendor_id, \errata_id, \enable, \new_c .endm @@ -40,7 +46,10 @@ .macro __ALTERNATIVE_CFG_2 old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \ new_c_2, vendor_id_2, errata_id_2, enable_2 886 : + .option push + .option norvc \old_c + .option pop 887 : ALT_NEW_CONTENT \vendor_id_1, \errata_id_1, \enable_1, \new_c_1 ALT_NEW_CONTENT \vendor_id_2, \errata_id_2, \enable_2, \new_c_2 @@ -70,7 +79,10 @@ ".popsection\n" \ ".subsection 1\n" \ "888 :\n" \ + ".option push\n" \ + ".option norvc\n" \ new_c "\n" \ + ".option pop\n" \ "889 :\n" \ ".previous\n" \ ".org . - (887b - 886b) + (889b - 888b)\n" \ @@ -79,7 +91,10 @@ #define __ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, enable) \ "886 :\n" \ + ".option push\n" \ + ".option norvc\n" \ old_c "\n" \ + ".option pop\n" \ "887 :\n" \ ALT_NEW_CONTENT(vendor_id, errata_id, enable, new_c) @@ -89,7 +104,10 @@ #define __ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1, \ new_c_2, vendor_id_2, errata_id_2, enable_2) \ "886 :\n" \ + ".option push\n" \ + ".option norvc\n" \ old_c "\n" \ + ".option pop\n" \ "887 :\n" \ ALT_NEW_CONTENT(vendor_id_1, errata_id_1, enable_1, new_c_1) \ ALT_NEW_CONTENT(vendor_id_2, errata_id_2, enable_2, new_c_2) -- 2.30.2