linux-kernel - [PATCH 0/5] x86-64: Remove syscall instructions at fixed addresses

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Date:	Fri, 27 May 2011 13:38:37 -0400
From:	Andy Lutomirski <luto@....EDU>
To:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	x86@...nel.org
Cc:	linux-kernel@...r.kernel.org, Andy Lutomirski <luto@....edu>
Subject: [PATCH 0/5] x86-64: Remove syscall instructions at fixed addresses

I lied about taking awhile to do this.

There are a bunch of syscall instructions in kernel space at fixed
addresses that user code can execute.

One is a time() fallback.  Patch 3/5 removes it.

Several are data that isn't marked NX.  Patch 2/5 makes vvars NX and
5/5 makes the HPET NX.

The last one is the gettimeofday fallback.  We need that, but it
doesn't have to be a real syscall.  Patch 3/5 adds int 0xCC (callable
only from the vsyscall page) that implements the gettimeofday fallback
and nothing else.

Patch 1/5 is just a dumb but harmless bug fix from the last vdso
series.

I've only tested this in KVM with a hacked-up initramfs, but Ingo
wanted it for 2.6.40, so here it is.

Andy Lutomirski (5):
  x86-64: Fix alignment of jiffies variable
  x86-64: Give vvars their own page
  x86-64: Remove kernel.vsyscall64 sysctl
  x86-64: Replace vsyscall gettimeofday fallback with int 0xcc
  x86-64: Map the HPET NX

 arch/x86/include/asm/fixmap.h        |    1 +
 arch/x86/include/asm/pgtable_types.h |    6 ++-
 arch/x86/include/asm/traps.h         |    4 ++
 arch/x86/include/asm/vgtod.h         |    1 -
 arch/x86/include/asm/vsyscall.h      |    6 ++
 arch/x86/include/asm/vvar.h          |   24 ++++-----
 arch/x86/kernel/entry_64.S           |    2 +
 arch/x86/kernel/hpet.c               |    2 +-
 arch/x86/kernel/traps.c              |    4 ++
 arch/x86/kernel/vmlinux.lds.S        |   27 ++++++----
 arch/x86/kernel/vsyscall_64.c        |   86 ++++++++++++++++++---------------
 arch/x86/vdso/vclock_gettime.c       |   55 ++++++++-------------
 tools/power/x86/turbostat/turbostat  |  Bin 0 -> 29200 bytes
 13 files changed, 117 insertions(+), 101 deletions(-)
 create mode 100755 tools/power/x86/turbostat/turbostat

-- 
1.7.5.1

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