On x86-64, they were just wasteful: with the explicitly added (now
unnecessary) padding, the size of the alternatives structure was 16
bytes, and an alignment of 8 bytes didn't hurt much.

However, it was still silly, since the natural size and alignment for
the structure is actually just 12 bytes, 4-byte aligned since commit
59e97e4d6fbc ("x86: Make alternative instruction pointers relative").
So removing the padding, and removing the extra alignment is just a good
idea.

On x86-32, the alignment of 4 bytes was correct, but was incorrectly
hardcoded as 8 bytes in <asm/alternative-asm.h>.  That header file had
used to be an x86-64 only header file, but various unification efforts
have made it be used for x86-32 too (ie the unification of rwlock and
rwsem).

That in turn caused x86-32 boot failures, because the extra alignment
would result in random zero-filled words in the altinstructions section,
causing oopses early at boot when doing alternative instruction
replacement.

So just remove all the alignment noise entirely.  It's wrong, and it's
unnecessary.  The section itself is already properly aligned by the
linker scripts, and all additions to the section had better be of the
proper 12-byte format, keeping it aligned.  So if the align directive
were to ever make a difference, that would be an indication of a serious
bug to begin with.

Reported-by: Werner Landgraf <w.landgraf@ru.r>
Acked-by: Andrew Lutomirski <luto@mit.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'kvm-updates/3.1' of git://github.com/avikivity/kvm:
  KVM: Fix instruction size issue in pvclock scaling

Commit de2d1a524e94 ("KVM: Fix register corruption in pvclock_scale_delta")
introduced a mul instruction that may have only a memory operand; the
assembler therefore cannot select the correct size:

   pvclock.s:229: Error: no instruction mnemonic suffix given and no register
operands; can't size instruction

In this example the assembler is:

         #APP
         mul -48(%rbp) ; shrd $32, %rdx, %rax
         #NO_APP

A simple solution is to use mulq.

Signed-off-by: Duncan Sands <baldrick@free.fr>
Signed-off-by: Avi Kivity <avi@redhat.com>

The nfsservctl system call is now gone, so we should remove all
linkage for it.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'stable/bug.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/tracing: Fix tracing config option properly
  xen: Do not enable PV IPIs when vector callback not present
  xen/x86: replace order-based range checking of M2P table by linear one
  xen: xen-selfballoon.c needs more header files

The order-based approach is not only less efficient (requiring a shift
and a compare, typical generated code looking like this

	mov	eax, [machine_to_phys_order]
	mov	ecx, eax
	shr	ebx, cl
	test	ebx, ebx
	jnz	...

whereas a direct check requires just a compare, like in

	cmp	ebx, [machine_to_phys_nr]
	jae	...

), but also slightly dangerous in the 32-on-64 case - the element
address calculation can wrap if the next power of two boundary is
sufficiently far away from the actual upper limit of the table, and
hence can result in user space addresses being accessed (with it being
unknown what may actually be mapped there).

Additionally, the elimination of the mistaken use of fls() here (should
have been __fls()) fixes a latent issue on x86-64 that would trigger
if the code was run on a system with memory extending beyond the 44-bit
boundary.

CC: stable@kernel.org
Signed-off-by: Jan Beulich <jbeulich@novell.com>
[v1: Based on Jeremy's feedback]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-tip:
  x86-64: Rework vsyscall emulation and add vsyscall= parameter
  x86-64: Wire up getcpu syscall
  x86: Remove unnecessary compile flag tweaks for vsyscall code
  x86-64: Add vsyscall:emulate_vsyscall trace event
  x86-64: Add user_64bit_mode paravirt op
  x86-64, xen: Enable the vvar mapping
  x86-64: Work around gold bug 13023
  x86-64: Move the "user" vsyscall segment out of the data segment.
  x86-64: Pad vDSO to a page boundary

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

getcpu is available as a vdso entry and an emulated vsyscall.
Programs that for some reason don't want to use the vdso should
still be able to call getcpu without relying on the slow emulated
vsyscall.  It costs almost nothing to expose it as a real syscall.

We also need this for the following patch in vsyscall=native mode.

Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/6b19f55bdb06a0c32c2fa6dba9b6f222e1fde999.1312988155.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Three places in the kernel assume that the only long mode CPL 3
selector is __USER_CS.  This is not true on Xen -- Xen's sysretq
changes cs to the magic value 0xe033.

Two of the places are corner cases, but as of "x86-64: Improve
vsyscall emulation CS and RIP handling"
(c9712944b2a12373cb6ff8059afcfb7e826a6c54), vsyscalls will segfault
if called with Xen's extra CS selector.  This causes a panic when
older init builds die.

It seems impossible to make Xen use __USER_CS reliably without
taking a performance hit on every system call, so this fixes the
tests instead with a new paravirt op.  It's a little ugly because
ptrace.h can't include paravirt.h.

Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/f4fcb3947340d9e96ce1054a432f183f9da9db83.1312378163.git.luto@mit.edu
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>