Conditionaly compile cmpxchg8b_emu.o and EXPORT_SYMBOL(cmpxchg8b_emu).

This reduces the kernel size a bit.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4AC43E7E.1000600@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

cmpxchg64() today generates, to quote Linus, "barf bag" code.

cmpxchg64() is about to get used in the scheduler to fix a bug there,
but it's a prerequisite that cmpxchg64() first be made non-sucking.

This patch turns cmpxchg64() into an efficient implementation that
uses the alternative() mechanism to just use the raw instruction on
all modern systems.

Note: the fallback is NOT smp safe, just like the current fallback
is not SMP safe. (Interested parties with i486 based SMP systems
are welcome to submit fix patches for that.)

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
[ fixed asm constraint bug ]
Fixed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090930170754.0886ff2e@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Change msr-reg.o to obj-y (it will be included in virtually every
kernel since it is used by the initialization code for AMD processors)
and add a separate C file to export its symbols to modules, so that
msr.ko can use them; on uniprocessors we bypass the helper functions
in msr.o and use the accessor functions directly via inlines.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <20090904140834.GA15789@elte.hu>
Cc: Borislav Petkov <petkovbb@googlemail.com>

The macro was defined in the 32-bit path as well - breaking the
build on 32-bit platforms:

  arch/x86/lib/msr-reg.S: Assembler messages:
  arch/x86/lib/msr-reg.S:53: Error: Bad macro parameter list
  arch/x86/lib/msr-reg.S:100: Error: invalid character '_' in mnemonic
  arch/x86/lib/msr-reg.S:101: Error: invalid character '_' in mnemonic

Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <tip-f6909f394c2d4a0a71320797df72d54c49c5927e@git.kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

msr-reg.S used the :req option on a macro argument, which wasn't
supported by gas 2.16.1 (but apparently by some earlier versions of
gas, just to be confusing.)  It isn't necessary, so just remove it.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>

Create _on_cpu helpers for {rw,wr}msr_safe_regs() analogously with the
other MSR functions.  This will be necessary to add support for these
to the MSR driver.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <petkovbb@gmail.com>

Add CFI annotations for native_{rd,wr}msr_safe_regs().
Simplify the 64-bit implementation: we don't allow the upper half
registers to be set, and so we can use them to carry state across the
operation.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <petkovbb@gmail.com>
LKML-Reference: <1251705011-18636-1-git-send-email-petkovbb@gmail.com>

native_{rdmsr,wrmsr}_safe_regs are two new interfaces which allow
presetting of a subset of eight x86 GPRs before executing the rd/wrmsr
instructions. This is needed at least on AMD K8 for accessing an erratum
workaround MSR.

Originally based on an idea by H. Peter Anvin.

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
LKML-Reference: <1251705011-18636-1-git-send-email-petkovbb@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Make rdmsr_on_cpus/wrmsr_on_cpus execute on the current CPU only if it
is in the supplied bitmask.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  cfq-iosched: reset oom_cfqq in cfq_set_request()
  block: fix sg SG_DXFER_TO_FROM_DEV regression
  block: call blk_scsi_ioctl_init()
  Fix congestion_wait() sync/async vs read/write confusion