From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227AshmqTHPCm4ndNACEm/2AXzA3kdgfLrqqdfKoluApAP3oTsIC0MBTQA23s/EerCCRy+a9 ARC-Seal: i=1; a=rsa-sha256; t=1518708749; cv=none; d=google.com; s=arc-20160816; b=xpMRBJXKTB/WHisUbLKUooGL3uBoQ/xElHcWrmJEUu0guQncOKq1sxZ/GTi1msF5PX otOcTP5Jt5P/DXgkPVoUZOb+iW5uh9bRr+9vNiKM02CM7cBZ8ooHMbIvkgXQykxgbMm8 /wX+MalDBzoWzZKcDiRaBG/DJPL07q1b7vIV3Fp4gs5OPGJOhaiMFMGioRznCgVubiOz PKZuMfsbeHUXFfSNxgVLRPXf7jnb7Yu2vlQUgP3KdhJc3kitomsXqBuBQF1gt/0zl1e2 kNTkROEDS4ro37JQH5JpMOWRGcPeLiS5aeF/05TSkh8aoXrYFiIRxs/673nlOA+kkBGF b98g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=WYZG+wRQyE6s1GDTw1uQKiAz13sxT8Yfq2QXqsAXkLg=; b=aRugueqNIzckWdxtjUfNVpOXcG69/W91Uad3lbT8xSaFTdaXX/T7R9Chr4bri5j/52 5uA2Rr6peVq3bMBEsGNkvhe5b/BT1QszGzgwg5/PA6NSCLwhiEFjNSL05oioKmOEV/py EjXDhahCeZQdDo8OGnzCM196I0F0mEwDiXm2YHZHUH/rpdCZjp0pdt46oO3+jA4VpjFL n5zTpDsW1z2NrrZ3RspaYRJk7dMpYmqYJnXsigu2wJVfCdipnch6F1a8AjN25I0aT9cU bARPOArvH5Mp9W7O+rOtxc4DwlsPv2zChsGGDIcZkf6+Td3g5iPJ4FzmuBsa6C5n7v/Y T96Q== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Will Deacon , Jayachandran C , Catalin Marinas , Ard Biesheuvel Subject: [PATCH 4.14 049/195] [Variant 3/Meltdown] arm64: Turn on KPTI only on CPUs that need it Date: Thu, 15 Feb 2018 16:15:40 +0100 Message-Id: <20180215151708.191962165@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180215151705.738773577@linuxfoundation.org> References: <20180215151705.738773577@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1592481545594577550?= X-GMAIL-MSGID: =?utf-8?q?1592481545594577550?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jayachandran C Commit 0ba2e29c7fc1 upstream. Whitelist Broadcom Vulcan/Cavium ThunderX2 processors in unmap_kernel_at_el0(). These CPUs are not vulnerable to CVE-2017-5754 and do not need KPTI when KASLR is off. Acked-by: Will Deacon Signed-off-by: Jayachandran C Signed-off-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/cpufeature.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -816,6 +816,13 @@ static bool unmap_kernel_at_el0(const st if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) return true; + /* Don't force KPTI for CPUs that are not vulnerable */ + switch (read_cpuid_id() & MIDR_CPU_MODEL_MASK) { + case MIDR_CAVIUM_THUNDERX2: + case MIDR_BRCM_VULCAN: + return false; + } + /* Defer to CPU feature registers */ return !cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_CSV3_SHIFT);