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From: Andy Lutomirski <>
To: "H. Peter Anvin" <>,
	Linus Torvalds <>,
	"" <>,, Borislav Petkov <>
Cc: Andy Lutomirski <>
Subject: [PATCH 0/2] x86_64: LRET to userspace
Date: Wed, 23 Jul 2014 08:34:10 -0700
Message-ID: <> (raw)

This series is based on tip/perf/urgent.  It should apply to any
recent kernel, but my test case [1] will OOPS without the fix in

The first patch or something like it is needed for 3.16, regardless
of any lret hackery -- I think it's making its way toward a pull
request this week, but I haven't seen it land in -tip yet.

I'm repeating it here because the LRET stuff won't work on paravirt,
and patch 1 puts the machinery for that in place.

tl;dr Read patch 2.  To test, apply patch 1 and consider basing on

[1] sigreturn_32 from

Andy Lutomirski (2):
  x86_64,entry,xen: Do not invoke espfix64 on Xen
  x86_64,entry: Use lret to return to userspace when possible

 arch/x86/include/asm/irqflags.h     |   3 +-
 arch/x86/include/asm/paravirt.h     |   4 ++
 arch/x86/include/asm/traps.h        |   6 ++
 arch/x86/kernel/cpu/mcheck/mce.c    |   2 +
 arch/x86/kernel/entry_64.S          | 121 ++++++++++++++++++++++++++++++------
 arch/x86/kernel/nmi.c               |  21 +++++++
 arch/x86/kernel/paravirt_patch_64.c |   2 -
 7 files changed, 136 insertions(+), 23 deletions(-)


             reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-23 15:34 Andy Lutomirski [this message]
2014-07-23 15:34 ` [PATCH 1/2] x86_64,entry,xen: Do not invoke espfix64 on Xen Andy Lutomirski
2014-07-28 22:33   ` [tip:x86/urgent] x86_64/entry/xen: " tip-bot for Andy Lutomirski
2014-07-29  3:39     ` Andy Lutomirski
2014-07-29  3:47       ` H. Peter Anvin
2014-07-23 15:34 ` [PATCH 2/2] x86_64,entry: Use lret to return to userspace when possible Andy Lutomirski

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