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

From: Andy Lutomirski
Date: Fri May 27 2011 - 13:39:06 EST


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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