Allocating PDA and GDT at boot is a pain.  Using simple per-cpu variables adds
happiness (although we need the GDT page-aligned for Xen, which we do in a
followup patch).

[akpm@linux-foundation.org: build fix]
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Because the command line is increased to 2048 characters after 2.6.21, it's
not possible for boot loaders and userspace tools to determine the length
of the command line the kernel can understand.  The benefit of knowing the
length is that users can be warned if the command line size is too long
which prevents surprise if things don't work after bootup.

This patch updates the boot protocol to contain a field called
"cmdline_size" that contain the length of the command line (excluding the
terminating zero).

The patch also adds missing fields (of protocol version 2.05) to the x86_64
setup code.
Signed-off-by: NBernhard Walle <bwalle@suse.de>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Alon Bar-Lev <alon.barlev@gmail.com>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

The specific case I am encountering is kdump under Xen with a 64 bit
hypervisor and 32 bit kernel/userspace.  The dump created is 64 bit due to
the hypervisor but the dump kernel is 32 bit for maximum compatibility.

It's possibly less likely to be useful in a purely native scenario but I
see no reason to disallow it.

[akpm@linux-foundation.org: build fix]
Signed-off-by: NIan Campbell <ian.campbell@xensource.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Acked-by: NVivek Goyal <vgoyal@in.ibm.com>
Cc: Horms <horms@verge.net.au>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

GCC (4.1 at least) unrolls it anyway, but I can't believe this code
was ever justifiable.  (I've also submitted a patch which cleans up
i386, which is even uglier).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Whenever we schedule, __switch_to calls load_esp0 which does:

	tss->esp0 = thread->esp0;

This is never initialized for the initial thread (ie "swapper"), so when we're
scheduling that, we end up setting esp0 to 0.  This is fine: the swapper never
leaves ring 0, so this field is never used.

lguest, however, gets upset that we're trying to used an unmapped page as our
kernel stack.  Rather than work around it there, let's initialize it.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

The lguest patches somehow managed to trigger this:

In file included from arch/i386/lguest/lguest.c:38:
include/asm/asm-offsets.h:67:1: warning: "VDSO_PRELINK" redefined
In file included from include/linux/elf.h:7,
                 from include/linux/module.h:15,
                 from include/linux/device.h:21,
                 from include/linux/interrupt.h:15,
                 from arch/i386/lguest/lguest.c:27:
include/asm/elf.h:140:1: warning: this is the location of the previous definition

I assume that using the same identifier twice was a bad idea..

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>

Create a document to explain how to use numa=fake in conjunction with cpusets
for coarse memory resource management.

An attempt to get more awareness and testing for this feature.

Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

remove the reporting of the constant_tsc flag from the "power management"
field in /proc/cpuinfo.  The NULL value there was replaced by "" because
the former would result in a printout of [8] if the flag is set.
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>

Extends the numa=fake x86_64 command-line option to split the remaining system
memory into nodes of fixed size.  Any leftover memory is allocated to a final
node unless the command-line ends with a comma.

For example:
  numa=fake=2*512,*128	gives two 512M nodes and the remaining system
			memory is split into nodes of 128M each.

This is beneficial for systems where the exact size of RAM is unknown or not
necessarily relevant, but the size of the remaining nodes to be allocated is
known based on their capacity for resource management.

Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Extends the numa=fake x86_64 command-line option to split the remaining
system memory into equal-sized nodes.

For example:
numa=fake=2*512,4*	gives two 512M nodes and the remaining system
			memory is split into four approximately equal
			chunks.

This is beneficial for systems where the exact size of RAM is unknown or not
necessarily relevant, but the granularity with which nodes shall be allocated
is known.

Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Extends the numa=fake x86_64 command-line option to allow for configurable
node sizes.  These nodes can be used in conjunction with cpusets for coarse
memory resource management.

The old command-line option is still supported:
  numa=fake=32	gives 32 fake NUMA nodes, ignoring the NUMA setup of the
		actual machine.

But now you may configure your system for the node sizes of your choice:
  numa=fake=2*512,1024,2*256
		gives two 512M nodes, one 1024M node, two 256M nodes, and
		the rest of system memory to a sixth node.

The existing hash function is maintained to support the various node sizes
that are possible with this implementation.

Each node of the same size receives roughly the same amount of available
pages, regardless of any reserved memory with its address range.  The total
available pages on the system is calculated and divided by the number of equal
nodes to allocate.  These nodes are then dynamically allocated and their
borders extended until such time as their number of available pages reaches
the required size.

Configurable node sizes are recommended when used in conjunction with cpusets
for memory control because it eliminates the overhead associated with scanning
the zonelists of many smaller full nodes on page_alloc().

Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Fix comments to represent the true number of quadwords in GDT.
Signed-off-by: NAhmed S. Darwish <darwish.07@gmail.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Acked-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

This patch makes the needlessly global vmi_pmd_clear() static.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndi Kleen <ak@suse.de>
Acked-by: NZachary Amsden <zach@vmware.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>

Reorder code to avoid multiple inclusion of elf.h.

#undef several symbols to avoid build errors over redefinitions.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Change mark_tsc_unstable() so it takes a string argument, which holds the
reason the TSC was marked unstable.

This is then displayed the first time mark_tsc_unstable is called.

This should help us better debug why the TSC was marked unstable on certain
systems and allow us to make sure we're not being overly paranoid when
throwing out this troublesome clocksource.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>

Work around a warning with -Wmissing-prototypes in
arch/i386/kernel/asm-offsets.c

The warning isn't gcc's fault - asm-offsets.c is simply a special file.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

clean up unneeded type cast by properly declare data type.
Signed-off-by: NKen Chen <kenchen@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>

Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

o Modpost generates warnings for i386 if compiled with CONFIG_RELOCATABLE=y

WARNING: vmlinux - Section mismatch: reference to .init.text:find_unisys_acpi_oem_table from .text between 'acpi_madt_oem_check' (at offset 0xc0101eda) and 'enable_apic_mode'
WARNING: vmlinux - Section mismatch: reference to .init.text:acpi_get_table_header_early from .text between 'acpi_madt_oem_check' (at offset 0xc0101ef0) and 'enable_apic_mode'
WARNING: vmlinux - Section mismatch: reference to .init.text:parse_unisys_oem from .text between 'acpi_madt_oem_check' (at offset 0xc0101f2e) and 'enable_apic_mode'
WARNING: vmlinux - Section mismatch: reference to .init.text:setup_unisys from .text between 'acpi_madt_oem_check' (at offset 0xc0101f37) and 'enable_apic_mode'WARNING: vmlinux - Section mismatch: reference to .init.text:parse_unisys_oem from .text between 'mps_oem_check' (at offset 0xc0101ec7) and 'acpi_madt_oem_check'
WARNING: vmlinux - Section mismatch: reference to .init.text:es7000_sw_apic from .text between 'enable_apic_mode' (at offset 0xc0101f48) and 'check_apicid_present'

o Some functions which are inline (acpi_madt_oem_check) are not inlined by
  compiler as these functions are accessed using function pointer. These
  functions are put in .text section and they in-turn access __init type
  functions hence modpost generates warnings.

o Do not iniline acpi_madt_oem_check, instead make it __init.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Enable system hashtable memory to be distributed among nodes on x86_64 NUMA

Forcing the kernel to use node interleaved vmalloc instead of bootmem for
the system hashtable memory (alloc_large_system_hash) reduces the memory
imbalance on node 0 by around 40MB on a 8 node x86_64 NUMA box:

Before the following patch, on bootup of a 8 node box:

Node 0 MemTotal:      3407488 kB
Node 0 MemFree:       3206296 kB
Node 0 MemUsed:        201192 kB
Node 0 Active:           7012 kB
Node 0 Inactive:          512 kB
Node 0 Dirty:               0 kB
Node 0 Writeback:           0 kB
Node 0 FilePages:        1912 kB
Node 0 Mapped:            420 kB
Node 0 AnonPages:        5612 kB
Node 0 PageTables:        468 kB
Node 0 NFS_Unstable:        0 kB
Node 0 Bounce:              0 kB
Node 0 Slab:             5408 kB
Node 0 SReclaimable:      644 kB
Node 0 SUnreclaim:       4764 kB

After the patch (or using hashdist=1 on the kernel command line):

Node 0 MemTotal:      3407488 kB
Node 0 MemFree:       3247608 kB
Node 0 MemUsed:        159880 kB
Node 0 Active:           3012 kB
Node 0 Inactive:          616 kB
Node 0 Dirty:               0 kB
Node 0 Writeback:           0 kB
Node 0 FilePages:        2424 kB
Node 0 Mapped:            380 kB
Node 0 AnonPages:        1200 kB
Node 0 PageTables:        396 kB
Node 0 NFS_Unstable:        0 kB
Node 0 Bounce:              0 kB
Node 0 Slab:             6304 kB
Node 0 SReclaimable:     1596 kB
Node 0 SUnreclaim:       4708 kB

I guess it is a good idea to keep HASHDIST_DEFAULT "on" for x86_64 NUMA
since x86_64 has no dearth of vmalloc space?  Or maybe enable hash
distribution for all 64bit NUMA arches?  The following patch does it only
for x86_64.

I ran a HPC MPI benchmark -- 'Ansys wingsolid', which takes up quite a bit of
memory and uses up tlb entries.  This was on a 4 way, 2 socket
Tyan AMD box (non vsmp), with 8G total memory (4G pernode).

The results with and without hash distribution are:

1. Vanilla - runtime of 1188.000s
2. With hashdist=1 runtime of 1154.000s

Oprofile output for the duration of run is:

1. Vanilla:
PU: AMD64 processors, speed 2411.16 MHz (estimated)
Counted L1_AND_L2_DTLB_MISSES events (L1 and L2 DTLB misses) with a unit
mask of 0x00 (No unit mask) count 500
samples  %        app name                 symbol name
163054    6.5513  libansys1.so             MultiFront::decompose(int, int,
Elemset *, int *, int, int, int)
162061    6.5114  libansys3.so             blockSaxpy6L_fd
162042    6.5107  libansys3.so             blockInnerProduct6L_fd
156286    6.2794  libansys3.so             maxb33_
87879     3.5309  libansys1.so             elmatrixmultpcg_
84857     3.4095  libansys4.so             saxpy_pcg
58637     2.3560  libansys4.so             .st4560
46612     1.8728  libansys4.so             .st4282
43043     1.7294  vmlinux-t                copy_user_generic_string
41326     1.6604  libansys3.so             blockSaxpyBackSolve6L_fd
41288     1.6589  libansys3.so             blockInnerProductBackSolve6L_fd

2. With hashdist=1
CPU: AMD64 processors, speed 2411.13 MHz (estimated)
Counted L1_AND_L2_DTLB_MISSES events (L1 and L2 DTLB misses) with a unit
mask of 0x00 (No unit mask) count 500
samples  %        app name                 symbol name
162993    6.9814  libansys1.so             MultiFront::decompose(int, int,
Elemset *, int *, int, int, int)
160799    6.8874  libansys3.so             blockInnerProduct6L_fd
160459    6.8729  libansys3.so             blockSaxpy6L_fd
156018    6.6826  libansys3.so             maxb33_
84700     3.6279  libansys4.so             saxpy_pcg
83434     3.5737  libansys1.so             elmatrixmultpcg_
58074     2.4875  libansys4.so             .st4560
46000     1.9703  libansys4.so             .st4282
41166     1.7632  libansys3.so             blockSaxpyBackSolve6L_fd
41033     1.7575  libansys3.so             blockInnerProductBackSolve6L_fd
35762     1.5318  libansys1.so             inner_product_sub
35591     1.5245  libansys1.so             inner_product_sub2
28259     1.2104  libansys4.so             addVectors
Signed-off-by: NPravin B. Shelar <pravin.shelar@calsoftinc.com>
Signed-off-by: NRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: NShai Fultheim <shai@scalex86.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Acked-by: NChristoph Lameter <clameter@engr.sgi.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

Signed-off-by: NAndi Kleen <ak@suse.de>

Previously it wasn't enabled in the binfmt_aout is a module case.
Signed-off-by: NAndi Kleen <ak@suse.de>

When compiling with -Os (which is default) the compiler defaults to it
anyways. And with -O2 it probably generates somewhat better (although
also larger) code.
Signed-off-by: NAndi Kleen <ak@suse.de>

Fix for the following patch. Provide dummy cpufreq functions when
CPUFREQ is not compiled in.

Cc: Andi Kleen <ak@suse.de>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndi Kleen <ak@suse.de>

o This patch moves the code to verify long mode and SSE to a common file.
  This code is now shared by trampoline.S, wakeup.S, boot/setup.S and
  boot/compressed/head.S

o So far we used to do very limited check in trampoline.S, wakeup.S and
  in 32bit entry point. Now all the entry paths are forced to do the
  exhaustive check, including SSE because verify_cpu is shared.

o I am keeping this patch as last in the x86 relocatable series because
  previous patches have got quite some amount of testing done and don't want
  to distrub that. So that if there is problem introduced by this patch, at
  least it can be easily isolated.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o Extend the bzImage protocol (same as i386) to allow bzImage loaders to
  load the protected mode kernel at non-1MB address. Now protected mode
  component is relocatable and can be loaded at non-1MB addresses.

o As of today kdump uses it to run a second kernel from a reserved memory
  area.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o X86_64 kernel should run from 2MB aligned address for two reasons.
	- Performance.
	- For relocatable kernels, page tables are updated based on difference
	  between compile time address and load time physical address.
	  This difference should be multiple of 2MB as kernel text and data
	  is mapped using 2MB pages and PMD should be pointing to a 2MB
	  aligned address. Life is simpler if both compile time and load time
	  kernel addresses are 2MB aligned.

o Flag the error at compile time if one is trying to build a kernel which
  does not meet alignment restrictions.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

This patch modifies the x86_64 kernel so that it can be loaded and run
at any 2M aligned address, below 512G.  The technique used is to
compile the decompressor with -fPIC and modify it so the decompressor
is fully relocatable.  For the main kernel the page tables are
modified so the kernel remains at the same virtual address.  In
addition a variable phys_base is kept that holds the physical address
the kernel is loaded at.  __pa_symbol is modified to add that when
we take the address of a kernel symbol.

When loaded with a normal bootloader the decompressor will decompress
the kernel to 2M and it will run there.  This both ensures the
relocation code is always working, and makes it easier to use 2M
pages for the kernel and the cpu.

AK: changed to not make RELOCATABLE default in Kconfig
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

Currently __pa_symbol is for use with symbols in the kernel address
map and __pa is for use with pointers into the physical memory map.
But the code is implemented so you can usually interchange the two.

__pa which is much more common can be implemented much more cheaply
if it is it doesn't have to worry about any other kernel address
spaces.  This is especially true with a relocatable kernel as
__pa_symbol needs to peform an extra variable read to resolve
the address.

There is a third macro that is added for the vsyscall data
__pa_vsymbol for finding the physical addesses of vsyscall pages.

Most of this patch is simply sorting through the references to
__pa or __pa_symbol and using the proper one.  A little of
it is continuing to use a physical address when we have it
instead of recalculating it several times.

swapper_pgd is now NULL.  leave_mm now uses init_mm.pgd
and init_mm.pgd is initialized at boot (instead of compile time)
to the physmem virtual mapping of init_level4_pgd.  The
physical address changed.

Except for the for EMPTY_ZERO page all of the remaining references
to __pa_symbol appear to be during kernel initialization.  So this
should reduce the cost of __pa in the common case, even on a relocated
kernel.

As this is technically a semantic change we need to be on the lookout
for anything I missed.  But it works for me (tm).
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o virt_to_page() call should be used on kernel linear addresses and not
  on kernel text and data addresses. Swsusp code uses it on kernel data
  (statically allocated swsusp_header).

o Allocate swsusp_header dynamically so that virt_to_page() can be used
  safely.

o I am changing this because in next few patches, __pa() on x86_64 will
  no longer support kernel text and data addresses and hibernation breaks.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o __pa() should be used only on kernel linearly mapped virtual addresses
  and not on kernel text and data addresses.

o Hibernation code needs to determine the physical address associated
  with kernel symbol to mark a section boundary which contains pages which
  don't have to be saved and restored during hibernate/resume operation.

o Move this piece of code in arch dependent section. So that architectures
  which don't have kernel text/data mapped into kernel linearly mapped
  region can come up with their own ways of determining physical addresses
  associated with a kernel text.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

With the rewrite of the SMP trampoline and the early page
allocator there is nothing that needs identity mapped pages,
once we start executing C code.

So add zap_identity_mappings into head64.c and remove
zap_low_mappings() from much later in the code.  The functions
 are subtly different thus the name change.

This also kills boot_level4_pgt which was from an earlier
attempt to move the identity mappings as early as possible,
and is now no longer needed.  Essentially I have replaced
boot_level4_pgt with trampoline_level4_pgt in trampoline.S
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o Moved wakeup_level4_pgt into the wakeup routine so we can
  run the kernel above 4G.

o Now we first go to 64bit mode and continue to run from trampoline and
  then then start accessing kernel symbols and restore processor context.
  This enables us to resume even in relocatable kernel context when
  kernel might not be loaded at physical addr it has been compiled for.

o Removed the need for modifying any existing kernel page table.

o Increased the size of the wakeup routine to 8K. This is required as
  wake page tables are on trampoline itself and they got to be at 4K
  boundary, hence one page is not sufficient.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o Various cleanups. One of the main purpose of cleanups is that make
  wakeup.S as close as possible to trampoline.S.

o Following are the changes
	- Indentations for comments.
	- Changed the gdt table to compact form and to resemble the
	  one in trampoline.S
	- Take the jump to 32bit from real mode using ljmpl. Makes code
	  more readable.
	- After enabling long mode, directly take a long jump for 64bit
	  mode. No need to take an extra jump to "reach_comaptibility_mode"
	- Stack is not used after real mode. So don't load stack in
 	  32 bit mode.
	- No need to enable PGE here.
	- No need to do extra EFER read, anyway we trash the read contents.
	- No need to enable system call (EFER_SCE). Anyway it will be
	  enabled when original EFER is restored.
	- No need to set MP, ET, NE, WP, AM bits in cr0. Very soon we will
  	  reload the original cr0 while restroing the processor state.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o Use appropriate names for 64bit regsiters.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o Get rid of dead code in wakeup.S

o We never restore from saved_gdt, saved_idt, saved_ltd, saved_tss, saved_cr3,
  saved_cr4, saved_cr0, real_save_gdt, saved_efer, saved_efer2. Get rid
  of of associated code.

o Get rid of bogus_magic, bogus_31_magic and bogus_magic2. No longer being
  used.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

This modifies the SMP trampoline and all of the associated code so
it can jump to a 64bit kernel loaded at an arbitrary address.

The dependencies on having an idenetity mapped page in the kernel
page tables for SMP bootup have all been removed.

In addition the trampoline has been modified to verify
that long mode is supported.  Asking if long mode is implemented is
down right silly but we have traditionally had some of these checks,
and they can't hurt anything.  So when the totally ludicrous happens
we just might handle it correctly.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>