start_cpu0() is defined in head_64.S for 64-bit. The function sets up stack and
jumps to start_secondary() for CPU0 wake up.
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1352835171-3958-8-git-send-email-fenghua.yu@intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Migrated SMP trampoline code to the real mode blob.
SMP trampoline code is not yet removed from
.x86_trampoline because it is needed by the wakeup
code.

[ hpa: always enable compiling startup_32_smp in head_32.S... it is
  only a few instructions which go into .init on UP builds, and it makes
  the rest of the code less #ifdef ugly. ]
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-6-git-send-email-jarkko.sakkinen@intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

If we get an exception during early boot, walk the exception table to
see if we should intercept it.  The main use case for this is to allow
rdmsr_safe()/wrmsr_safe() during CPU initialization.

Since the exception table is currently sorted at runtime, and fairly
late in startup, this code walks the exception table linearly.  We
obviously don't need to worry about modules, however: none have been
loaded at this point.

[ v2: Use early_fixup_exception() instead of linear search ]

Link: http://lkml.kernel.org/r/1334794610-5546-5-git-send-email-hpa@zytor.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

GET_CR2_INTO_RCX is asinine: it is only used in one place, the actual
paravirt call returns the value in %rax, not %rcx; and the one place
that wants it wants the result in %r9.  We actually generate as a
result of this call:

       call ...
       movq %rax, %rcx
       xorq %rax, %rax		/* this value isn't even used... */
       movq %rcx, %r9

At least make the macro do what the paravirt call does, which is put
the value into %rax.

Nevermind the fact that the macro clobbers all the volatile registers.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1334794610-5546-4-git-send-email-hpa@zytor.com
Cc: Glauber de Oliveira Costa <glommer@parallels.com>

Add a symbolic constant for the bitmask which states which exceptions
carry an error code.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1334794610-5546-3-git-send-email-hpa@zytor.com

We want to allow NMI handlers to have breakpoints to be able to
remove stop_machine from ftrace, kprobes and jump_labels. But if
an NMI interrupts a current breakpoint, and then it triggers a
breakpoint itself, it will switch to the breakpoint stack and
corrupt the data on it for the breakpoint processing that it
interrupted.

Instead, have the NMI check if it interrupted breakpoint processing
by checking if the stack that is currently used is a breakpoint
stack. If it is, then load a special IDT that changes the IST
for the debug exception to keep the same stack in kernel context.
When the NMI is done, it puts it back.

This way, if the NMI does trigger a breakpoint, it will keep
using the same stack and not stomp on the breakpoint data for
the breakpoint it interrupted.
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Common infrastructure for low memory trampolines.  This code installs
the trampolines permanently in low memory very early.  It also permits
multiple pieces of code to be used for this purpose.

This code also introduces a standard infrastructure for computing
symbol addresses in the trampoline code.

The only change to the actual SMP trampolines themselves is that the
64-bit trampoline has been made reusable -- the previous version would
overwrite the code with a status variable; this moves the status
variable to a separate location.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <4D5DFBE4.7090104@intel.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Matthieu Castet <castet.matthieu@free.fr>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>

Load initial_gs as two 32-bit values instead of splitting a 64-bit value.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
LKML-Reference: <1279371808-24804-3-git-send-email-brgerst@gmail.com>
Reviewed-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

In particular, several occurances of funny versions of 'success',
'unknown', 'therefore', 'acknowledge', 'argument', 'achieve', 'address',
'beginning', 'desirable', 'separate' and 'necessary' are fixed.
Signed-off-by: NDaniel Mack <daniel@caiaq.de>
Cc: Joe Perches <joe@perches.com>
Cc: Junio C Hamano <gitster@pobox.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

This prevents kernel threads from inheriting non-null segment
selectors, and causing optimizations in __switch_to() to be
ineffective.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Cc: Tim Blechmann <tim@klingt.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jan Beulich <JBeulich@novell.com>
LKML-Reference: <1259165856-3512-1-git-send-email-brgerst@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In the first 2MB, kernel text is co-located with kernel static
page tables setup by head_64.S.  CONFIG_DEBUG_RODATA chops this
2MB large page mapping to small 4KB pages as we mark the kernel text as RO,
leaving the static page tables as RW.

With CONFIG_DEBUG_RODATA disabled, OLTP run on NHM-EP shows 1% improvement
with 2% reduction in system time and 1% improvement in iowait idle time.

To recover this, move the kernel static page tables to .data section, so that
we don't have to break the first 2MB of kernel text to small pages with
CONFIG_DEBUG_RODATA.
Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20091014220254.063193621@sbs-t61.sc.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This patch changes the remaining direct references to
.bss.page_aligned in C and assembly code to use the macros in
include/linux/linkage.h.
Signed-off-by: NTim Abbott <tabbott@ksplice.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

This has the consequence of changing the section name use for head
code from ".text.head" to ".head.text".  It also eliminates the
".text.head" output section (instead placing head code at the start of
the .text output section), which should be harmless.

This patch only changes the sections in the actual kernel, not those
in the compressed boot loader.
Signed-off-by: NTim Abbott <tabbott@ksplice.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

asm/desc.h is included in three assembly files, but the only macro
it defines, GET_DESC_BASE, is never used. This patch removes the
includes, removes the macro GET_DESC_BASE and the ASSEMBLY guard
from asm/desc.h.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: cleanup
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

NEXT_PAGE already has 'balign' so no
need to keep this redundant one.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Cc: heukelum@fastmail.fm
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup and bug fix

Use the linker to create symbols for certain per-cpu variables
that are offset by __per_cpu_load.  This allows the removal of
the runtime fixup of the GDT pointer, which fixes a bug with
resume reported by Jiri Slaby.
Reported-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Acked-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: x86_64 percpu area layout change, irq_stack now at the beginning

Now that the PDA is empty except for the stack canary, it can be removed.
The irqstack is moved to the start of the per-cpu section.  If the stack
protector is enabled, the canary overlaps the bottom 48 bytes of the irqstack.

tj: * updated subject
    * dropped asm relocation of irq_stack_ptr
    * updated comments a bit
    * rebased on top of stack canary changes
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Impact: cleanup

Use cpu_number to determine if the adjustment is necessary.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

[ Based on original patch from Christoph Lameter and Mike Travis. ]

As pda is now allocated in percpu area, it can easily be made a proper
percpu variable.  Make it so by defining per cpu symbol from linker
script and declaring it in C code for SMP and simply defining it for
UP.  This change cleans up code and brings SMP and UP closer a bit.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

[ Based on original patch from Christoph Lameter and Mike Travis. ]

Currently pdas and percpu areas are allocated separately.  %gs points
to local pda and percpu area can be reached using pda->data_offset.
This patch folds pda into percpu area.

Due to strange gcc requirement, pda needs to be at the beginning of
the percpu area so that pda->stack_canary is at %gs:40.  To achieve
this, a new percpu output section macro - PERCPU_VADDR_PREALLOC() - is
added and used to reserve pda sized chunk at the start of the percpu
area.

After this change, for boot cpu, %gs first points to pda in the
data.init area and later during setup_per_cpu_areas() gets updated to
point to the actual pda.  This means that setup_per_cpu_areas() need
to reload %gs for CPU0 while clearing pda area for other cpus as cpu0
already has modified it when control reaches setup_per_cpu_areas().

This patch also removes now unnecessary get_local_pda() and its call
sites.

A lot of this patch is taken from Mike Travis' "x86_64: Fold pda into
per cpu area" patch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

[ Based on original patch from Christoph Lameter and Mike Travis. ]

CPU startup code in head_64.S loaded address of a zero page into %gs
for temporary use till pda is loaded but address to the actual pda is
available at the point.  Load the real address directly instead.

This will help unifying percpu and pda handling later on.

This patch is mostly taken from Mike Travis' "x86_64: Fold pda into
per cpu area" patch.
Signed-off-by: NTejun Heo <tj@kernel.org>

[ Based on original patch from Christoph Lameter and Mike Travis. ]

This patch makes percpu symbols zerobased on x86_64 SMP by adding
PERCPU_VADDR() to vmlinux.lds.h which helps setting explicit vaddr on
the percpu output section and using it in vmlinux_64.lds.S.  A new
PHDR is added as existing ones cannot contain sections near address
zero.  PERCPU_VADDR() also adds a new symbol __per_cpu_load which
always points to the vaddr of the loaded percpu data.init region.

The following adjustments have been made to accomodate the address
change.

* code to locate percpu gdt_page in head_64.S is updated to add the
  load address to the gdt_page offset.

* __per_cpu_load is used in places where access to the init data area
  is necessary.

* pda->data_offset is initialized soon after C code is entered as zero
  value doesn't work anymore.

This patch is mostly taken from Mike Travis' "x86_64: Base percpu
variables at zero" patch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix debug/crash printout

Since errorcode is popped out, RIP is on the top of the stack.
Use real RIP value instead of wrong CS.
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: arjan@linux.intel.com
Cc: venkatesh.pallipadi@intel.com
Cc: jeremy@goop.org
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This reverts commit 033786969d1d1b5af12a32a19d3a760314d05329.

Suresh Siddha reported that this broke booting on his 2GB testbox.
Reported-by: NSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add the Xen entrypoint and ELF notes to head_64.S.  Adapts xen-head.S
to compile either 32-bit or 64-bit.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Early fixmap will allocate its own L1 pagetable page for fixmap
mappings, so there's no need to preallocate one.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Consistently set _PAGE_GLOBAL in _PAGE_KERNEL flags.  This makes 32-
and 64-bit code consistent, and removes some special cases where
__PAGE_KERNEL* did not have _PAGE_GLOBAL set, causing confusion as a
result of the inconsistencies.

This patch only affects x86-64, which generally always supports PGD.
The x86-32 patch is next.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Ingo Molnar wrote:
> -tip auto-testing found pagetable corruption (CPA self-test failure):
>
> [   32.956015] CPA self-test:
> [   32.958822]  4k 2048 large 508 gb 0 x 2556[ffff880000000000-ffff88003fe00000] miss 0
> [   32.964000] CPA ffff88001d54e000: bad pte 1d4000e3
> [   32.968000] CPA ffff88001d54e000: unexpected level 2
> [   32.972000] CPA ffff880022c5d000: bad pte 22c000e3
> [   32.976000] CPA ffff880022c5d000: unexpected level 2
> [   32.980000] CPA ffff8800200ce000: bad pte 200000e3
> [   32.984000] CPA ffff8800200ce000: unexpected level 2
> [   32.988000] CPA ffff8800210f0000: bad pte 210000e3
>
> config and full log can be found at:
>
>  http://redhat.com/~mingo/misc/config-Mon_Jun_30_11_11_51_CEST_2008.bad
>  http://redhat.com/~mingo/misc/log-Mon_Jun_30_11_11_51_CEST_2008.bad

Phew.  OK, I've worked this out.  Short version is that's it's a false
alarm, and there was no real failure here.  Long version:

    * I changed the code to create the physical mapping pagetables to
      reuse any existing mapping rather than replace it.   Specifically,
      reusing an pud pointed to by the pgd caused this symptom to appear.
    * The specific PUD being reused is the one created statically in
      head_64.S, which creates an initial 1GB mapping.
    * That mapping doesn't have _PAGE_GLOBAL set on it, due to the
      inconsistency between __PAGE_* and PAGE_*.
    * The CPA test attempts to clear _PAGE_GLOBAL, and then checks to
      see that the resulting range is 1) shattered into 4k pages, and 2)
      has no _PAGE_GLOBAL.
    * However, since it didn't have _PAGE_GLOBAL on that range to start
      with, change_page_attr_clear() had nothing to do, and didn't
      bother shattering the range,
    * resulting in the reported messages

The simple fix is to set _PAGE_GLOBAL in level2_ident_pgt.

An additional fix to make CPA testing more robust by using some other
pagetable bit (one of the unused available-to-software ones).  This
would solve spurious CPA test warnings under Xen which uses _PAGE_GLOBAL
for its own purposes (ie, not under guest control).

Also, we should revisit the use of _PAGE_GLOBAL in asm-x86/pgtable.h,
and use it consistently, and drop MAKE_GLOBAL.  The first time I
proposed it it caused breakages in the very early CPA code; with luck
that's all fixed now.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mark McLoughlin <markmc@redhat.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Set __PAGE_OFFSET to the most negative possible address +
16*PGDIR_SIZE.  The gap is to allow a space for a hypervisor to fit.
The gap is more or less arbitrary, but it's what Xen needs.

When booting native, kernel/head_64.S has a set of compile-time
generated pagetables used at boot time.  This patch removes their
absolutely hard-coded layout, and makes it parameterised on
__PAGE_OFFSET (and __START_KERNEL_map).
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

i386 and x86_64 used two different schemes for maintaining the gdt.
With this patch, x86_64 initial gdt table is defined in a .c file,
same way as i386 is now. Also, we call it "gdt_page", and the descriptor,
"early_gdt_descr". This way we achieve common naming, which can allow for
more code integration.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

call x86_64's init_rsp stack_start, just as i386 does.
Put a zeroed stack segment for consistency. With this,
we can eliminate one ugly ifdef in smpboot.c.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Since the trampoline code is now used for ACPI resume from suspend to RAM,
the trampoline page tables have to be fixed up during boot not only on SMP
systems, but also on UP systems that use the trampoline.

Reference: http://bugzilla.kernel.org/show_bug.cgi?id=10923Reported-by: NDionisus Torimens <djtm@gmx.net>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: pm list <linux-pm@lists.linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We should better use already defined flags from processor-flags.h instead
of defining own ones

[>>> object code check >>>]

original
md5sum: 9cfa6dbf045a046bb5dfb85f8bcfe8c4  arch/x86/kernel/head_64.o
   text    data     bss     dec     hex filename
  37361    4432    8192   49985    c341 arch/x86/kernel/head_64.o

patched
md5sum: 9cfa6dbf045a046bb5dfb85f8bcfe8c4  arch/x86/kernel/head_64.o
   text    data     bss     dec     hex filename
  37361    4432    8192   49985    c341 arch/x86/kernel/head_64.o

[<<< object code check <<<]
Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Move wakeup code to .c, so that video mode setting code can be shared
between boot and wakeup. Remove nasty assembly code in 64-bit case by
re-using trampoline code. Stack setup was fixed to clear high 16bits
of %esp, maybe that fixes some machines.

.c code sharing and morse code was done H. Peter Anvin, Sam Ravnborg
reviewed kbuild related stuff, and it seems okay to him. Rafael did
some cleanups.

[rjw:
* Made the patch stop breaking compilation on x86-32
* Added arch/x86/kernel/acpi/sleep.h
* Got rid of compiler warnings in arch/x86/kernel/acpi/sleep.c
* Fixed 32-bit compilation on x86-64 systems
* Added include/asm-x86/trampoline.h and fixed the non-SMP
  compilation on 64-bit x86
* Removed arch/x86/kernel/acpi/sleep_32.c which was not used
* Fixed some breakage caused by the integration of smpboot.c done
  under us in the meantime]
Signed-off-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Reviewed-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Currently they are in .text.head because the rest of head_64.S.
.text.head is not removed as init data, but the early exception handlers
should be because they are not needed after early boot of the BP.
So move them over.
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: mingo@elte.hu
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The early exception handlers are currently set up using a macro
recursion. There is only one user left. Replace the macro with a
standard loop in place.

Noop patch, just a cleanup.

[ tglx@linutronix.de: simplified ]
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: mingo@elte.hu
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>