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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C555EC369BD for ; Wed, 16 Apr 2025 12:38:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:Content-Type:MIME-Version:Message-Id:Date:Subject: To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=71wKjVaQs7hqyTxjh1kMjKuzN2E/xBEPPrkr9jMBtHo=; b=NGqTRaTsr4MMA+ B2RqkmdkZYumkM63N/NyWcbnhYSBL30tVOXs/Rd6YsvxhBiFvHWnX2utQyCuHnKoEu7oiAhM/YxQE FYvdRVvKWynKjT86vb5akL2AtvJ4M4CjzJbA/xOS/+wARG5LhgSdhzjgpJoF+nCfBrswB8hw9UadW B5nqjvHtPO1a9M/uKwxMxYRfnM4yUnhlnYQTxATiJQaivZOwVNOO/ls4FNJA8FuBLOwSum6der/cv /xrLxPFBSGuyi0uHM8/yfS4rb5/7ehUDL3UlUzIyGljY8VpFSyInQMq9FfSockZiyrDpiPaWzkXag nXrm/Wl5b4nQw1J1GscA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u522N-00000009Xrp-01C8; Wed, 16 Apr 2025 12:38:43 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u51zX-00000009XJa-0B4L for linux-arm-kernel@lists.infradead.org; Wed, 16 Apr 2025 12:35:48 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 860B9450C3; Wed, 16 Apr 2025 12:35:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 728C2C4CEEA; Wed, 16 Apr 2025 12:35:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744806946; bh=TaSTqmfUWdAWMCyCDuaW1LXUde2ewk+gb8KOAkYw6WY=; h=From:To:Cc:Subject:Date:From; b=cLTgulfogp2VrnwUMNRZB2EWHhXgTDNoWo9e3XjOE2b0kxWIIdcGcQZ9u0cQ+8dm4 E8odt1SXTW+ZebbQQZdBZfn2a+7zlN4LfaVeqTjt6khmfWrAmqwUpKB87BCUinEMe3 ixyKHDsYDPfyls2I/sIZ84TwEFH/4RY80QEJ0sYiXudyKanuBQoXu6E1SB6YNA1UYX IfHmFRW0w0yxTHixEWSHk6QE7X7Zn1wNV8RkQ6cH9KENz2R3ouyn7pVsL5sQbDDkgv +lIKIbG4U06Z5I/RN0ambB4x4jljwCZqTqiYmYR6tF5XL13Gxf1aQ4x2SAdpwt6N5a DFWFolhRXyvyw== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1u51zU-0063Mi-AR; Wed, 16 Apr 2025 13:35:44 +0100 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Subject: [PATCH] arm64: Remove checks for broken Cavium HW from the PI code Date: Wed, 16 Apr 2025 13:35:34 +0100 Message-Id: <20250416123534.1108220-1-maz@kernel.org> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, ada.coupriediaz@arm.com, catalin.marinas@arm.com, will@kernel.org, shameerali.kolothum.thodi@huawei.com, oliver.upton@linux.dev X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250416_053547_121969_D5F77B16 X-CRM114-Status: GOOD ( 16.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Will Deacon , Oliver Upton , Shameer Kolothum , Catalin Marinas Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Calling into the MIDR checking framework from the PI code has recently become much harder, due to the new fancy "multi-MIDR" support that relies on tables being populated at boot time, but not that early that they are available to the PI code. There are additional issues with this framework, as the code really isn't position independend *at all*. This leads to some ugly breakages, as reported by Ada. It so appears that the only reason for the PI code to call into the MIDR checking code is to cope with The Most Broken ARM64 System Ever, aka Cavium ThunderX, which cannot deal with nG attributes that result of the combination of KASLR and KPTI as a consequence of Erratum 27456. Rather than adding extra complexity for something that is actually a very dead horse, let's simply drop that check. On my own machine, the firmware doesn't provide a KASLR seed, preventing the pathological case to show up. And if someone does have a broken box that passes a seed to the kernel, "nokaslr" on the command-line is an easy enough workaround. Fixes: c8c2647e69bed ("arm64: Make  _midr_in_range_list() an exported function") Reported-by: Ada Couprie Diaz Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/3d97e45a-23cf-419b-9b6f-140b4d88de7b@arm.com Cc: Catalin Marinas Cc: Will Deacon Cc: Shameer Kolothum Cc: Oliver Upton --- arch/arm64/include/asm/mmu.h | 11 ----------- arch/arm64/kernel/cpu_errata.c | 2 +- arch/arm64/kernel/image-vars.h | 4 ---- 3 files changed, 1 insertion(+), 16 deletions(-) diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index 30a29e88994ba..6e8aa8e726015 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -94,17 +94,6 @@ static inline bool kaslr_requires_kpti(void) return false; } - /* - * Systems affected by Cavium erratum 24756 are incompatible - * with KPTI. - */ - if (IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) { - extern const struct midr_range cavium_erratum_27456_cpus[]; - - if (is_midr_in_range_list(cavium_erratum_27456_cpus)) - return false; - } - return true; } diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index b55f5f7057502..6b0ad5070d3e0 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -335,7 +335,7 @@ static const struct midr_range cavium_erratum_23154_cpus[] = { #endif #ifdef CONFIG_CAVIUM_ERRATUM_27456 -const struct midr_range cavium_erratum_27456_cpus[] = { +static const struct midr_range cavium_erratum_27456_cpus[] = { /* Cavium ThunderX, T88 pass 1.x - 2.1 */ MIDR_RANGE(MIDR_THUNDERX, 0, 0, 1, 1), /* Cavium ThunderX, T81 pass 1.0 */ diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index 5e3c4b58f2790..2004b4f41ade6 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -47,10 +47,6 @@ PROVIDE(__pi_id_aa64smfr0_override = id_aa64smfr0_override); PROVIDE(__pi_id_aa64zfr0_override = id_aa64zfr0_override); PROVIDE(__pi_arm64_sw_feature_override = arm64_sw_feature_override); PROVIDE(__pi_arm64_use_ng_mappings = arm64_use_ng_mappings); -#ifdef CONFIG_CAVIUM_ERRATUM_27456 -PROVIDE(__pi_cavium_erratum_27456_cpus = cavium_erratum_27456_cpus); -PROVIDE(__pi_is_midr_in_range_list = is_midr_in_range_list); -#endif PROVIDE(__pi__ctype = _ctype); PROVIDE(__pi_memstart_offset_seed = memstart_offset_seed); -- 2.39.2