From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 574C9606A31C for ; Fri, 13 Nov 2026 09:57:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=4L1GjViu; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ERhw5e7X 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-Unsubscribe-Post:List-Owner; bh=mDCrY3T+VfZdtZlaxXLBeMjsbFqx3DNTndl6jA165tY=; b=4L1GjViuD+UYQ1X3UFBx0R4ISE zOUV4aXQS0Ktatjg0ST9Hda+ORRAUeqXLTB7hSK62smjYBJYmwrjzB1CCypyPjRNRWapMjPcbUd8j mPzvp7l6iLr5bxJj8aDAn6ms+8L79cUIijCyzqQ2v183exzS7KwGkMgb/pDx2P35pxNN4wR5bGQYe UaqjLslMwdRTNTzJmM37TBU3kx3xs3gUFBrFJHdq9shRXJp/7l1U8TqQ+g+/2DixglIt963smIH90 u+AN4xJYyfHbVWoMIZq/43Mb8nMXciUVxpOD7bsAz/Xv906/eQmgSSIc/1AVU1Kcw6PJrOSVRR8h6 qLsdwuBA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRo1u-0000000CHDZ-11E3; Fri, 13 Nov 2026 09:57:10 +0000 Received: from out-163.mta1.migadu.com ([2001:41d0:203:375::a3] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRo1s-0000000CHCL-0SM2 for linux-arm-kernel@lists.infradead.org; Fri, 13 Nov 2026 09:57:09 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=lOsW+kFmaNLmxVVYY/0ykrsQLE9+KLi12EdY2vBuJyg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794563824; v=1; x=1795168624; b=ERhw5e7XrXdCNhbB0G9amRhzx9HP44fEGZN0/+aNbQxXV3shm5fOYU7bMAhWeniBqoEoI+cn P0+EjyXPl1sdFM0vsOw4W/otv2kvhNK/PNt6gMw8wjp26TEF32F7wqdiF4Q5c+RD4e03EYYSfpj VfjPq3tKjtAXjTrmqSEs9muI= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id 9aff9a9311754da3; Fri, 13 Nov 2026 09:57:04 +0000 X-Mizu-Trace-ID: 9aff9a9311754da3 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Catalin Marinas , Will Deacon Cc: Mark Rutland , Marc Zyngier , Suzuki K Poulose , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Fuad Tabba Subject: [PATCH] arm64: cpufeature: Check the override in __read_sysreg_by_encoding() Date: Fri, 13 Nov 2026 09:57:01 +0000 Message-ID: <20261113095701.2042858-1-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261113_015708_354258_5922EFCE X-CRM114-Status: UNSURE ( 8.53 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.1 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 __read_sysreg_by_encoding() backs the capability checks a secondary runs before its cpuinfo is stored, and folds an ID register override into the value it reads without checking it against that CPU. A secondary whose field is below an override the boot CPU accepted passes verification and comes online without the feature. Apply the override through arm64_ftr_reg_override(), as the cpuinfo store does, so that it only applies where it is safe against that CPU's value. Fixes: b3341ae0efa2 ("arm64: cpufeature: Use IDreg override in __read_sysreg_by_encoding()") Reported-by: Catalin Marinas Link: https://lore.kernel.org/all/abwXl35xQ2ze1XwJ@arm.com/ Suggested-by: Suzuki K Poulose Signed-off-by: Fuad Tabba --- Notes: Based on v7.4-rc1 (6628e7d4c6b2), where arm64_ftr_reg_override() was added. arch/arm64/kernel/cpufeature.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 34c5c03c0c9b4..3980acdd6e1b7 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1415,7 +1415,6 @@ EXPORT_SYMBOL_GPL(read_sanitised_ftr_reg); */ u64 __read_sysreg_by_encoding(u32 sys_id) { - struct arm64_ftr_reg *regp; u64 val; switch (sys_id) { @@ -1468,13 +1467,7 @@ u64 __read_sysreg_by_encoding(u32 sys_id) return 0; } - regp = get_arm64_ftr_reg(sys_id); - if (regp) { - val &= ~regp->override->mask; - val |= (regp->override->val & regp->override->mask); - } - - return val; + return arm64_ftr_reg_override(sys_id, val); } #include base-commit: 6628e7d4c6b25c8d18f1345e3a20d21829aae7e4 -- 2.47.3