From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227KENHxDpaq+Hm9Rg+SK99HZRpLxo1AjgytqTdHTiPi597wP2VVfE9V927iEiKH/nTjdAQo ARC-Seal: i=1; a=rsa-sha256; t=1517227211; cv=none; d=google.com; s=arc-20160816; b=tmxjRkRmqEAb+o7gGmUv1+umeRhR6adFi3y1HBzZV69EzcHg77EFlcTG8HX5PDO6xu u4gYHm0LPexyWIRlOlmtG3y5KSbU7pHas6y37SZsBKuUvfS3nFDGWyYRea04wH8Uan+c W8XOR6eu1ANkAtUYnbNg5n8o61voTyN6hzInMdbEzKH3n6U+1eBFBjiydx7UcHkD6JDf agHJ5MlG7Pe3QBPLpaqZ9H8MP2ZEg+1AQgOHnw+5jruynCTmxK1joIMJMX1EuJFxNHq7 hZ4Um/JPeogm+ka0Bq7Z+DOBRl0dF0eQpJh+RAWtOADFH/mYWAdOB6YS/7jHccGZMGSz JCew== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:in-reply-to:mime-version:user-agent:date :message-id:from:references:cc:to:subject:arc-authentication-results; bh=+arcH67Kejum2H+j7FbgH3zAyrP4NvU+EHU3y2Hzuuc=; b=sImPZff3FHyBt8s3scsI+NIuL/u7ZWKVW/sSyFEvwEPbRUIubwO8PN6BwTSSV54nsz rqbIPJ4LzTZODuEyGtpCzzfb0UpRjlAFKu1WhkGeWu25ClYMPiuSCIJOXFkB4UejVMqq oLv2ckXTfBkO8tO0Pxubqm1xWAQo79LmmKcAIELrmTnbR2+IlpwgJUGDg6XrqHUVChCd uSoXF+pPJOokrdwicSeC+5bJHO50cG/EVrp0cbbGfCoaX9K3nwMkQQMBmmUrqvqiEPZ7 SKpI0oqQSijQvr0xXtrYkfBdJjjh4qIoA5ihD93Yf3AfphAfAQstHTcuIen3IqCxbIc4 YCcw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of slash.tmp@free.fr designates 212.27.42.5 as permitted sender) smtp.mailfrom=slash.tmp@free.fr Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of slash.tmp@free.fr designates 212.27.42.5 as permitted sender) smtp.mailfrom=slash.tmp@free.fr Subject: Re: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict Indirect Branch Speculation To: Greg Kroah-Hartman Cc: LKML , Linux ARM , Marc Zyngier , Will Deacon , Arnd Bergmann References: <1516566497.9814.78.camel@infradead.org> <1516572013.9814.109.camel@infradead.org> <1516638426.9521.20.camel@infradead.org> <20180123072930.soz25cyky3u4hpgv@gmail.com> <20180123075358.nztpyxympwfkyi2a@gmail.com> <1516699832.9521.123.camel@infradead.org> <20180125171616.GA25130@kroah.com> From: Mason Message-ID: <1b430c16-2090-41e3-82d7-ef3d9b63fe2b@free.fr> Date: Mon, 29 Jan 2018 12:59:46 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0 SeaMonkey/2.49.1 MIME-Version: 1.0 In-Reply-To: <20180125171616.GA25130@kroah.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1590140582166248265?= X-GMAIL-MSGID: =?utf-8?q?1590928040692134252?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: [ Dropping large CC list ] On 25/01/2018 18:16, Greg Kroah-Hartman wrote: > On Thu, Jan 25, 2018 at 05:19:04PM +0100, Mason wrote: > >> On 23/01/2018 10:30, David Woodhouse wrote: >> >>> Skylake takes predictions from the generic branch target buffer when >>> the RSB underflows. >> >> Adding LAKML. >> >> AFAIU, some ARM Cortex cores have the same optimization. >> (A9 maybe, A17 probably, some recent 64-bit cores) >> >> Are there software work-arounds for Spectre planned for arm32 and arm64? > > Yes, I think they are currently buried in one of the arm64 trees, and > they have been posted to the mailing list a few times in the past. Found the burial ground, thanks Greg. https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=kpti Via https://developer.arm.com/support/security-update "For Cortex-R8, Cortex-A8, Cortex-A9, and Cortex-A17, invalidate the branch predictor using a BPIALL instruction." The latest arm32 patch series was submitted recently: https://www.spinics.net/lists/arm-kernel/msg630892.html Regards.