From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELuV5pq3CpquxE95K/y10bPksOJdFIfj96APluyKm5raSkXzE8I6VIW5tvIDzk/YwrXcuGAm ARC-Seal: i=1; a=rsa-sha256; t=1520824071; cv=none; d=google.com; s=arc-20160816; b=c1bDeFY33LWa/nYXDQ6Lp8a9bUyG6LPhWgNf33sHHOUgZcTXMgI++SxvYOt+E6t+BK DTmPwhfsS8CxIg34l2NTnu7xjp7rjE9Xv8nGtojbED7nX6j3k0TMRfC26A3diyO9HovE SjmjiSbEkZpGXbyrh2aLgR3cItJQquCEW7pgtjQQdZJxvaPfnMA32RcD/Vndl34Hxzho 0Wy/wA0ZytcSJKF2/go7zisUciHtw2+MDybOij+8+s9iYQpxqj5eX9nmeg+M4Ws/cZnt g633P64FiIGoKcy4tv8Q9I9N6/0voAKB0n27Z1QXXYXBLSK/NpYw0Suux2W9aN0GSArl 1HfQ== 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=RI+YyaC9qrOFVH98jegAbkYTH4P6teHu31M5eAcmn5M=; b=qWOBEMIllGkWE376jhm/ce/dn4Nspn02YqXBFYoRwR5c92ffBrckHVWIXt7VIav7g8 cNxT56onBTce3RIOJFoAg1DzVcaeXSSmLai0G5Rcfpnp4wsKyYb2ANWUUhKsflcwJJ8L F4pQ66XG9ipy3/3J7yaGULcZ6HZgw3kpg52AWflMx7ocvbnOwJSScH2xwAm2X7QL4DTF gjFlvIXPVpFHsxTsOcFflLowvIEGa6dB9lqlpe3AE9CxllsUbySeA9DoWW4ehM3AgtNo tnCPMFRaJEOSBQesa7AWnEjgKImwach6cbYOqvax0cOMAZ4s+dKBW58faEeGP0Sib+d+ erUg== 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, "Paolo Bonzini" , "Ashok Raj" , "Thomas Gleixner" , "Jun Nakajima" , "Dan Williams" , "Arjan Van De Ven" , "Peter Zijlstra" , "Josh Poimboeuf" , "Greg KH" , "David Woodhouse" , "Andrea Arcangeli" , "Dave Hansen" , "Jason Baron" , "Juergen Gross" , "Alok Kataria" , "Asit Mallick" , "Rusty Russell" , "Andy Lutomirski" , "Tim Chen" , "Andi Kleen" , "Linus Torvalds" Date: Mon, 12 Mar 2018 03:06:12 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 61/76] 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?1594699621640830967?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.16.56-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 3.16: 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 @@ -2271,8 +2271,6 @@ 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 @@ -41,17 +41,6 @@ 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) \ @@ -574,9 +563,6 @@ 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;