x86: Remove obsolete comment in uapi/e820.h

A comment introduced by this old commit:

  028b785888c5 ("x86 boot: extend some internal memory map arrays to handle larger EFI input")

had to do with some nested preprocessor directives.  The
directives were split into separate files by this commit:

  af170c5061dd ("UAPI: (Scripted) Disintegrate arch/x86/include/asm")

The comment explaining their interaction was retained and is now
present in arch/x86/include/uapi/asm/e820.h.  This comment is no
longer correct, so delete it.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Link: http://lkml.kernel.org/r/1400521824-21040-1-git-send-email-ross.zwisler@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86/tty/serial/8250: Resolve missing-field-initializers warnings

Resolve some missing-field-initializers warnings by using
designated initialization in the expansion of the
SERIAL_PORT_DFNS macro.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Link: http://lkml.kernel.org/r/1409972149-26272-1-git-send-email-jeffrey.t.kirsher@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86/tty/serial/8250: Clean up the asm/serial.h include file a bit

 - correct spelling
 - align fields vertically to make things more readable
 - make the layout of magic defines more obvious

Cc: Mark Rustad <mark.d.rustad@intel.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Link: http://lkml.kernel.org/r/1409972149-26272-1-git-send-email-jeffrey.t.kirsher@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86/kbuild: Eliminate duplicate command line options

The options -mno-mmx and -mno-sse are unconditionally added to
KBUILD_CFLAGS in both branches of an ifeq and through a
$(cc-option) further down. We can safely remove the first
instances.

In fact, since the -mno-mmx and -mno-sse options were introduced
simultaneous with the other two options in the $(cc-option)
[according to http://www.gnu.org/software/gcc/gcc-3.1/changes.html],
and since the former were unconditionally used, one can deduce that
only gcc versions knowing about all four are supported. So also
eliminate the $(cc-option) wrap.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Peter Foley <pefoley2@pefoley.com>
Link: http://lkml.kernel.org/r/1410365139-24440-1-git-send-email-linux@rasmusvillemoes.dk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86/smpboot: Initialize secondary CPU only if master CPU will wait for it

Hang is observed on virtual machines during CPU hotplug,
especially in big guests with many CPUs. (It reproducible
more often if host is over-committed).

It happens because master CPU gives up waiting on
secondary CPU and allows it to run wild. As result
AP causes locking or crashing system. For example
as described here:

  https://lkml.org/lkml/2014/3/6/257

If master CPU have sent STARTUP IPI successfully,
and AP signalled to master CPU that it's ready
to start initialization, make master CPU wait
indefinitely till AP is onlined.

To ensure that AP won't ever run wild, make it
wait at early startup till master CPU confirms its
intention to wait for AP. If AP doesn't respond in 10
seconds, the master CPU will timeout and cancel
AP onlining.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1403266991-12233-1-git-send-email-imammedo@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86/smpboot: Speed up suspend/resume by avoiding 100ms sleep for CPU offline during S3

With certain kernel configurations, CPU offline consumes more than
100ms during S3.

It's a timing related issue: native_cpu_die() would occasionally fall
into a 100ms sleep when the CPU idle loop thread marked the CPU state
to DEAD too slowly.

What native_cpu_die() does is that it polls the CPU state and waits
for 100ms if CPU state hasn't been marked to DEAD. The 100ms sleep
doesn't make sense and is purely historic.

To avoid such long sleeping, this patch adds a 'struct completion'
to each CPU, waits for the completion in native_cpu_die() and wakes
up the completion when the CPU state is marked to DEAD.

Tested on an Intel Xeon server with 48 cores, Ivybridge and on
Haswell laptops. The CPU offlining cost on these machines is
reduced from more than 100ms to less than 5ms. The system
suspend time is reduced by 2.3s on the servers.

Borislav and Prarit also helped to test the patch on an AMD
machine and a few systems of various sizes and configurations
(multi-socket, single-socket, no hyper threading, etc.). No
issues were seen.

Tested-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: srostedt@redhat.com
Cc: toshi.kani@hp.com
Cc: imammedo@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1409039025-32310-1-git-send-email-tianyu.lan@intel.com
[ Improved a few minor details in the code, cleaned up the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86: Speed up ___preempt_schedule*() by using THUNK helpers

___preempt_schedule() does SAVE_ALL/RESTORE_ALL but this is
suboptimal, we do not need to save/restore the callee-saved
register. And we already have arch/x86/lib/thunk_*.S which
implements the similar asm wrappers, so it makes sense to
redefine ___preempt_schedule() as "THUNK ..." and remove
preempt.S altogether.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921184153.GA23727@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86/lib/Makefile: Remove the unnecessary "+= thunk_64.o"

Trivial. We have "lib-y += thunk_$(BITS).o" at the start, no
need to add thunk_64.o if !CONFIG_X86_32.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140921184232.GB23727@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86/relocs: Make per_cpu_load_addr static

per_cpu_load_addr is only used for 64-bit relocations, but is
declared in both configurations of relocs.c - with different
types.  This has undefined behaviour in general.  GNU ld is
documented to use the larger size in this case, but other tools
may differ and some warn about this.

References: https://bugs.debian.org/748577
Reported-by: Michael Tautschnig <mt@debian.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: 748577@bugs.debian.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1411561812.3659.23.camel@decadent.org.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86: Improve cmpxchg16b_emu.S

- don't include unneeded headers
- don't open-code PER_CPU_VAR()
- drop redundant entry point label
- complete unwind annotations
- use .L prefix on local label to not clutter the symbol table

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/542290BC020000780003807D@mail.emea.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
x86: Improve cmpxchg8b_emu.S

- don't include unneeded headers
- drop redundant entry point label
- complete unwind annotations
- use .L prefix on local labels to not clutter the symbol table

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/5422917E0200007800038081@mail.emea.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
x86: Unwind-annotate thunk_32.S

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/542291CA0200007800038085@mail.emea.novell.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 asm updates from Ingo Molnar:
 "The changes in this cycle were:

   - Speed up the x86 __preempt_schedule() implementation
   - Fix/improve low level asm code debug info annotations"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Unwind-annotate thunk_32.S
  x86: Improve cmpxchg8b_emu.S
  x86: Improve cmpxchg16b_emu.S
  x86/lib/Makefile: Remove the unnecessary "+= thunk_64.o"
  x86: Speed up ___preempt_schedule*() by using THUNK helpers
Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 bootup updates from Ingo Molnar:
 "The changes in this cycle were:

   - Fix rare SMP-boot hang (mostly in virtual environments)

   - Fix build warning with certain (rare) toolchains"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/relocs: Make per_cpu_load_addr static
  x86/smpboot: Initialize secondary CPU only if master CPU will wait for it
Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 build update from Ingo Molnar:
 "A single commit that simplifies the no-FPU-ops build options"

* 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kbuild: Eliminate duplicate command line options
Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cleanups from Ingo Molnar:
 "Three small cleanups"

* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/tty/serial/8250: Clean up the asm/serial.h include file a bit
  x86/tty/serial/8250: Resolve missing-field-initializers warnings
  x86: Remove obsolete comment in uapi/e820.h
Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cpu offlining patch from Ingo Molnar:
 "This tree includes a single commit that speeds up x86 suspend/resume
  by replacing a naive 100msec sleep based polling loop with proper
  completion notification.

  This gives some real suspend/resume benefit on servers with larger
  core counts"

* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/smpboot: Speed up suspend/resume by avoiding 100ms sleep for CPU offline during S3