kernel/Documentation, branch linux-3.2.y

dm thin: fix documentation relative to low water mark threshold

2018-05-31T23:30:08Z

commit 9b28a1102efc75d81298198166ead87d643a29ce upstream. Fixes: 1. The use of "exceeds" when the opposite of exceeds, falls below, was meant. 2. Properly speaking, a table can not exceed a threshold. It emphasizes the important point, which is that it is the userspace daemon's responsibility to check for low free space when a device is resumed, since it won't get a special event indicating low free space in that situation. Signed-off-by: mulhern Signed-off-by: Mike Snitzer Signed-off-by: Ben Hutchings

ext4: correct documentation for grpid mount option

2018-05-31T23:30:06Z

commit 9f0372488cc9243018a812e8cfbf27de650b187b upstream. The grpid option is currently described as being the same as nogrpid. Signed-off-by: Ernesto A. Fernández Signed-off-by: Theodore Ts'o Signed-off-by: Ben Hutchings

x86/paravirt: Remove 'noreplace-paravirt' cmdline option

2018-03-19T18:58:38Z

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: Document array_index_nospec

2018-03-19T18:58:36Z

commit f84a56f73dddaeac1dba8045b007f742f61cd2da upstream. Document the rationale and usage of the new array_index_nospec() helper. Signed-off-by: Mark Rutland Signed-off-by: Will Deacon Signed-off-by: Dan Williams Signed-off-by: Thomas Gleixner Reviewed-by: Kees Cook Cc: linux-arch@vger.kernel.org Cc: Jonathan Corbet Cc: Peter Zijlstra Cc: gregkh@linuxfoundation.org Cc: kernel-hardening@lists.openwall.com Cc: torvalds@linux-foundation.org Cc: alan@linux.intel.com Link: https://lkml.kernel.org/r/151727413645.33451.15878817161436755393.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ben Hutchings

x86/pti: Document fix wrong index

2018-03-19T18:58:34Z

commit 98f0fceec7f84d80bc053e49e596088573086421 upstream. In section <2. Runtime Cost>, fix wrong index. Signed-off-by: zhenwei.pi Signed-off-by: Thomas Gleixner Cc: dave.hansen@linux.intel.com Link: https://lkml.kernel.org/r/1516237492-27739-1-git-send-email-zhenwei.pi@youruncloud.com Signed-off-by: Ben Hutchings

x86/spectre: Add boot time option to select Spectre v2 mitigation

2018-03-19T18:58:31Z

commit da285121560e769cc31797bba6422eea71d473e0 upstream. Add a spectre_v2= option to select the mitigation used for the indirect branch speculation vulnerability. Currently, the only option available is retpoline, in its various forms. This will be expanded to cover the new IBRS/IBPB microcode features. The RETPOLINE_AMD feature relies on a serializing LFENCE for speculation control. For AMD hardware, only set RETPOLINE_AMD if LFENCE is a serializing instruction, which is indicated by the LFENCE_RDTSC feature. [ tglx: Folded back the LFENCE/AMD fixes and reworked it so IBRS integration becomes simple ] Signed-off-by: David Woodhouse Signed-off-by: Thomas Gleixner Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel Cc: Andi Kleen Cc: Josh Poimboeuf Cc: thomas.lendacky@amd.com Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Jiri Kosina Cc: Andy Lutomirski Cc: Dave Hansen Cc: Kees Cook Cc: Tim Chen Cc: Greg Kroah-Hartman Cc: Paul Turner Link: https://lkml.kernel.org/r/1515707194-20531-5-git-send-email-dwmw@amazon.co.uk [bwh: Backported to 3.2: adjust filename, context] Signed-off-by: Ben Hutchings

sysfs/cpu: Fix typos in vulnerability documentation

2018-03-19T18:58:29Z

commit 9ecccfaa7cb5249bd31bdceb93fcf5bedb8a24d8 upstream. Fixes: 87590ce6e ("sysfs/cpu: Add vulnerability folder") Signed-off-by: David Woodhouse Signed-off-by: Thomas Gleixner Signed-off-by: Ben Hutchings

sysfs/cpu: Add vulnerability folder

2018-03-19T18:58:29Z

commit 87590ce6e373d1a5401f6539f0c59ef92dd924a9 upstream. As the meltdown/spectre problem affects several CPU architectures, it makes sense to have common way to express whether a system is affected by a particular vulnerability or not. If affected the way to express the mitigation should be common as well. Create /sys/devices/system/cpu/vulnerabilities folder and files for meltdown, spectre_v1 and spectre_v2. Allow architectures to override the show function. Signed-off-by: Thomas Gleixner Reviewed-by: Greg Kroah-Hartman Reviewed-by: Konrad Rzeszutek Wilk Cc: Peter Zijlstra Cc: Will Deacon Cc: Dave Hansen Cc: Linus Torvalds Cc: Borislav Petkov Cc: David Woodhouse Link: https://lkml.kernel.org/r/20180107214913.096657732@linutronix.de [bwh: Backported to 3.2: CPU device class is a sysdev_class, not a normal device class] Signed-off-by: Ben Hutchings

x86/Documentation: Add PTI description

2018-03-19T18:58:27Z

commit 01c9b17bf673b05bb401b76ec763e9730ccf1376 upstream. Add some details about how PTI works, what some of the downsides are, and how to debug it when things go wrong. Also document the kernel parameter: 'pti/nopti'. Signed-off-by: Dave Hansen Signed-off-by: Thomas Gleixner Reviewed-by: Randy Dunlap Reviewed-by: Kees Cook Cc: Moritz Lipp Cc: Daniel Gruss Cc: Michael Schwarz Cc: Richard Fellner Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Hugh Dickins Cc: Andi Lutomirsky Link: https://lkml.kernel.org/r/20180105174436.1BC6FA2B@viggo.jf.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings

gcov: compile specific gcov implementation based on gcc version

2018-03-19T18:58:23Z

commit 17c568d60af5a810208baf116dc174a2005c6c3e upstream. Compile the correct gcov implementation file for the specific gcc version. Signed-off-by: Frantisek Hrbata Cc: Jan Stancek Cc: Kees Cook Acked-by: Peter Oberparleiter Cc: Rusty Russell Cc: Arnd Bergmann Cc: Andy Gospodarek Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings