From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 19 Oct 2022 15:55:04 +0200 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1ol9XF-000l1Z-PB for lore@lore.pengutronix.de; Wed, 19 Oct 2022 15:55:04 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1ol9XC-0003vW-U4 for lore@pengutronix.de; Wed, 19 Oct 2022 15:55:03 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=fuu8e/E1nsEkZZMTdZ/5pRbJsh0VzbhFK4scRfpVREc=; b=IUlkbmiEC41C4LnApwkVz+wG0u yz2CfHR8klOZ0Qi9k75akINV0YMdn9mavmCcSIuEcMzZjeN1QUbyrByEt/mkYNPkNPiZ4onibDZLn SnU3hdKBqk9c0nLmSNHucNyaLkO2tI8kx2kMBmFZHdFy+rtwvIosYBMkbwEhzpQnQ6NsULlXsd89F 9CTsRZCWSnHIk1qTMBHhJKyrsNxPdsILq9OaJ02fkO4EIJFLL/fsix0IkC6TautIa1Kz8b2Y/Qt1j 8c4TGaFR0vttFthV2xM7YhEeuctbaBJJIp0B3RlZQn//4j2SL8nPOyHfLEHB3XcCAw0V7ySvYjxE/ 2sRTPKUA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ol9Vm-002LfC-0C; Wed, 19 Oct 2022 13:53:34 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ol9Vd-002LcS-UA for barebox@lists.infradead.org; Wed, 19 Oct 2022 13:53:27 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1ol9Vc-0003cV-HC; Wed, 19 Oct 2022 15:53:24 +0200 Received: from [2a0a:edc0:0:1101:1d::ac] (helo=dude04.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1ol9Vb-0008Ec-Qu; Wed, 19 Oct 2022 15:53:23 +0200 Received: from afa by dude04.red.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1ol9Vb-009akZ-0H; Wed, 19 Oct 2022 15:53:23 +0200 From: Ahmad Fatoum To: barebox@lists.infradead.org Cc: Ahmad Fatoum Date: Wed, 19 Oct 2022 15:53:22 +0200 Message-Id: <20221019135322.2283270-1-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221019_065325_992403_0391D438 X-CRM114-Status: GOOD ( 10.05 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.ext.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.7 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH master v2] Kbuild: disable ARM64 pointer authentication X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.ext.pengutronix.de) The aarch64 cross-compiler built with Yocto's kirkstone release configures -mbranch-protection=standard as default. The resulting PACIASP/AUTIASP instructions are interpreted as NOPs by existing CPUs, but they increase image size and misalign the barebox header in ENTRY_FUNCTION(). Also on ARMv8.3+, where they serve a purpose, we wouldn't benefit from them as we don't setup any pointer authentication keys. Thus disable it. The misaligned barebox header caused is_barebox_arm_head to fail, breaking all code that verified barebox' header, like i.MX8MM imx-usb-loader barebox-side support and barebox_update for some ARM64 SoCs without a SoC-specific header. Signed-off-by: Ahmad Fatoum --- This is a workaround. ENTRY_FUNCTION() should be rewritten for ARM64, so we don't expect function prologue to be exactly two bytes long. Signed-off-by: Ahmad Fatoum v1 -> v2: - revised commit message after understanding ramification better. --- Makefile | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Makefile b/Makefile index 98da09f18523..3737265316e9 100644 --- a/Makefile +++ b/Makefile @@ -659,6 +659,11 @@ KBUILD_CFLAGS += $(call cc-option,-fno-stack-check) # Platforms that have their setjmp appropriately implemented may override this KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none) +# We don't have the necessary infrastructure to benefit from ARMv8.3+ pointer +# authentication. On older CPUs, they are interpreted as NOPs and blot the +# code and break less portable code that expects a very specific code layout +KBUILD_CFLAGS += $(call cc-option,-mbranch-protection=none) + KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) # Align the bit size of userspace programs with the kernel -- 2.30.2