From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELtBZ9ZOxtPIv8u3zLD/NvkGG19st80wDjAqcT5zwJCdGxKpUe44K6usL2hQnntl5XMSmCjf ARC-Seal: i=1; a=rsa-sha256; t=1520824069; cv=none; d=google.com; s=arc-20160816; b=X1FnRC+5xmDO8cNQLcaIwtPhTwvLKDpU2Ggy7Cv0Ooa39bZl62TbETi5O20UTUFEuJ 2alGaQuJrhJaEI8IQLr92XpV6rPvjhU8jxsdj3E1flDkOYyojaow6AtMfzoxVKZ5wl1u 6Qo7w9PVzV7sim2xQ1bF84kZM0rhA0xLA/FBWwt2sXkh74TY7zGnIJhC2uNJEs1XnxWA RGxlMYGZuEQZt5ivt2Bog+WkqnH+uB2VlwVSouklcie71jiTXoWK+AOQeA7ZkIMQo45S ok+6Owau+QvYh1QooYMRgnc2jle+gj6c24TrD5BXBgrwx64/Zq1pv0aaE0HUg0ClqUjB wisA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=in-reply-to:subject:message-id:date:cc:to:from:mime-version :content-transfer-encoding:content-disposition :arc-authentication-results; bh=WB7rCqSi+6F2x9YYzMwt6R26XcReKZzWtkrIqAuq8AM=; b=M+WAxd7ligTMy2+SZ6ZZtugHxetMpFTrJlIF+JCwoH62TwMp7lRbsBedljnlQPuIS0 1mOGtQmSoiZETs4kHFHtchojAj4L+yb554dmafj677H/nFaJGnOshjJwVEFcU3dcDVLj 8Aq5kwcjGxTt+3Nryxoy1XH6nEPGiGFIyua2qLhdRjzu1dSOLJBKLxHcnkxZgkWRxpN3 XY/xUspilLVoTXqYLgkKoLPn6TMx+lEzOz27TECcy2sWQiXrj/zE9I8dS9YJ/191g/7h 1NhVWSF4VUgBic2A5z6kys9kuS7NjSpUJSJN7xigp2dPH0BuPi+nJiI2juK5XpAGXeu0 uEug== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of ben@decadent.org.uk designates 88.96.1.126 as permitted sender) smtp.mailfrom=ben@decadent.org.uk Authentication-Results: mx.google.com; spf=pass (google.com: domain of ben@decadent.org.uk designates 88.96.1.126 as permitted sender) smtp.mailfrom=ben@decadent.org.uk Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Ashok Raj" , "Asit Mallick" , "Jun Nakajima" , "Andy Lutomirski" , "Tim Chen" , "David Woodhouse" , "Alok Kataria" , "Jason Baron" , "Paolo Bonzini" , "Greg KH" , "Thomas Gleixner" , "Rusty Russell" , "Andi Kleen" , "Andrea Arcangeli" , "Dan Williams" , "Peter Zijlstra" , "Linus Torvalds" , "Arjan Van De Ven" , "Josh Poimboeuf" , "Juergen Gross" , "Dave Hansen" Date: Mon, 12 Mar 2018 03:03:34 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 091/104] x86/paravirt: Remove 'noreplace-paravirt' cmdline option In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594699619255898843?= X-GMAIL-MSGID: =?utf-8?q?1594699619255898843?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.2.101-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Josh Poimboeuf commit 12c69f1e94c89d40696e83804dd2f0965b5250cd upstream. The 'noreplace-paravirt' option disables paravirt patching, leaving the original pv indirect calls in place. That's highly incompatible with retpolines, unless we want to uglify paravirt even further and convert the paravirt calls to retpolines. As far as I can tell, the option doesn't seem to be useful for much other than introducing surprising corner cases and making the kernel vulnerable to Spectre v2. It was probably a debug option from the early paravirt days. So just remove it. Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner Reviewed-by: Juergen Gross Cc: Andrea Arcangeli Cc: Peter Zijlstra Cc: Andi Kleen Cc: Ashok Raj Cc: Greg KH Cc: Jun Nakajima Cc: Tim Chen Cc: Rusty Russell Cc: Dave Hansen Cc: Asit Mallick Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Jason Baron Cc: Paolo Bonzini Cc: Alok Kataria Cc: Arjan Van De Ven Cc: David Woodhouse Cc: Dan Williams Link: https://lkml.kernel.org/r/20180131041333.2x6blhxirc2kclrq@treble [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings --- Documentation/kernel-parameters.txt | 2 -- arch/x86/kernel/alternative.c | 14 -------------- 2 files changed, 16 deletions(-) --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1839,8 +1839,6 @@ bytes respectively. Such letter suffixes norandmaps Don't use address space randomization. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space - noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops - noreplace-smp [X86-32,SMP] Don't replace SMP instructions with UP alternatives --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -39,17 +39,6 @@ static int __init setup_noreplace_smp(ch } __setup("noreplace-smp", setup_noreplace_smp); -#ifdef CONFIG_PARAVIRT -static int __initdata_or_module noreplace_paravirt = 0; - -static int __init setup_noreplace_paravirt(char *str) -{ - noreplace_paravirt = 1; - return 1; -} -__setup("noreplace-paravirt", setup_noreplace_paravirt); -#endif - #define DPRINTK(fmt, args...) \ do { \ if (debug_alternative) \ @@ -583,9 +572,6 @@ void __init_or_module apply_paravirt(str struct paravirt_patch_site *p; char insnbuf[MAX_PATCH_LEN]; - if (noreplace_paravirt) - return; - for (p = start; p < end; p++) { unsigned int used;