From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226qmY8jwEh8NVtjFVz3aiILyD2sP3Cop+o3iOeNU+qDGY7mDXL+IsqghLszvWMv9N6FPg0j ARC-Seal: i=1; a=rsa-sha256; t=1518709227; cv=none; d=google.com; s=arc-20160816; b=Ffc7Q5m4yb2ZKZY34NiOEipaZG98Qh3V3aiaxQCeXOi3VZ+uZ/i+DZZyPxaPhvm/lY 0mDN0UNTOwGMUzsTN55hOKrqIwyDgI0MroCYUpL0zh+h75Jx1Uf2GYUU9IN7JZfA7Dza l3VrH99CKWbXIYdsAIlSJU26ytjlLzrWnfIX0zF6X3h0uLIZHhWTwUY/a0PnnUFKdVwY MPmXELgF6G7yhC+50zD+8vYAuvqI6blCNQxIcLZZWRIN+s3joX1EE+IqnBaKng5s4C26 EVjv8qnm6QnToVhHxdBf1Cp4rVpFRmf7glh8mMuIGWnCfbzJZEVhZE/AJrUW3a0Mv5Qy PIlw== 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=k9gPN6pTLVozOQV+YLT9huuW0cbXmm9lt7/xEzryPbU=; b=x5x7kMJekYaDgDn14SZlnOeXS9KKpgHbgBbhJV4/qekxHMi0ju5f6MiLaZ13yeTH/B Jv/Cpn4FiHpgx5VWZ3qOz/w0mX+no2Syg8x4bcWKKZn3Poy9NLou+jqGeqnZf5OfbJbo Sc38U36YII+232+1b04BbwUCw8r/rI0eFH0SdfTNl3dYpHjXat9HdgHJyeLUT5hCXNoz 10Ub65GyhpxAjLJQa0TYQ9JeJzqJTa+FDklDw/1Zb3OqtrTHKi3b4N/PAE8zFM6fz9Tt dM6tEf/mcC04XfFean3TpX9ve9nrprd9AV0PNjGB53QEBdi1HrDsFjPqKcuZQfkenlLF nuCg== 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 Subject: [PATCH 4.15 041/202] [Variant 3/Meltdown] arm64: Turn on KPTI only on CPUs that need it Date: Thu, 15 Feb 2018 16:15:41 +0100 Message-Id: <20180215151715.310098043@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180215151712.768794354@linuxfoundation.org> References: <20180215151712.768794354@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?1592482046801107500?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-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: 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 @@ -866,6 +866,13 @@ 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);