Bug 822302

Summary:	kernel: x86-64: Rework vsyscall emulation and add vsyscall= parameter [mrg-2.1]
Product:	Red Hat Enterprise MRG	Reporter:	Eugene Teo (Security Response) <eteo>
Component:	realtime-kernel	Assignee:	John Kacur <jkacur>
Status:	CLOSED NOTABUG	QA Contact:	David Sommerseth <davids>
Severity:	high	Docs Contact:
Priority:	high
Version:	2.2	CC:	bhu, jkacur, lgoncalv, ovasik, pmatouse, security-response-team, williams
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:	822300	Environment:
Last Closed:	2012-05-22 11:27:07 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	822300
Bug Blocks:	822292, 822301

Description Eugene Teo (Security Response) 2012-05-17 01:23:22 UTC

+++ This bug was initially created as a clone of Bug #822300 +++

Description of problem:
There are three choices:
vsyscall=native: Vsyscalls are native code that issues the corresponding syscalls.

vsyscall=emulate (default): Vsyscalls are emulated by instruction fault traps, tested in the bad_area path.  The actual contents of the vsyscall page is the same as the vsyscall=native case except that it's marked NX.  This way programs that make assumptions about what the code in the page does will not be confused when they read that code.

vsyscall=none: Trying to execute a vsyscall will segfault.

Signed-off-by: Andy Lutomirski <luto>
Link: http://lkml.kernel.org/r/8449fb3abf89851fd6b2260972666a6f82542284.1312988155.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa.com>

Upstream commit:
http://git.kernel.org/linus/3ae36655

Comment 1 John Kacur 2012-05-22 11:26:10 UTC

git describe --contains 3ae36655
v3.1-rc2~16^2

We should tick with the default setting unless we notice -rt perf impacts in the future.

Nothing to do here.