This is needed on MIPS where the same mechanism as get_user() is used to
intercept bus error exceptions for some hardware probes.  Without this
patch modpost will throw spurious warnings:

  LD      vmlinux
  SYSMAP  System.map
  SYSMAP  .tmp_System.map
  MODPOST vmlinux
WARNING: arch/mips/sgi-ip22/built-in.o(__dbe_table+0x0): Section mismatch: reference to .init.text:
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

gcc puts data into .data.rel or .data.rel.* on some architectures (e.g.
ia64) or under certain conditions, so whatever is legal relative to
.data should also be legal for those other sections. Fixes a few
modpost warnings on ia64.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Previously we did do the check on the .o files used to link
vmlinux but that failed to find questionable references across
the .o files.
Create a dedicated vmlinux.o file used only for section mismatch checks
that uses the defualt linker script so section does not get renamed.

The vmlinux.o may later be used as part of the the final link of vmlinux
but for now it is used fo section mismatch only.
For a defconfig build this is instant but for an allyesconfig this
add two minutes to a full build (that anyways takes ~2 hours).
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

arm uses a lot of ops structures named *_timer that has legitimite
references to .init.text.
So let's add this variable to the list of variables that may reference
.init.text without causing any warning.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Replaced this with a __init_refok marker
in front of fb_find_logo().

I think that the __initdata marker for the logo's are
wrong but I have not justified this so I did not remove it.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Replace the hardcoded variable name apic_es7000 in modpost
with a __initdata_refok marker.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

The .exit.text section may be discarded either at build or at runtime.
So let modpost warn if this situation is detected.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Move more checks from whitelist to the section check functions.
Remove the redundent pci_fixup check.
Renumber the patterns.
No functional changes.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

There were a great deal of overlap between the two functions
that check which sections may reference .init.text and .exit.text.
Factor out common check to a separate function and
sort entries in the original functions.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

.note* sections are ELF notes, which are typically used by external
tools to examine the kernel image.  Since this is removed from any
runtime consideration, it's OK to reference any section from a .note*
section.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

The .paravirtprobe section is obsolete, so modpost doesn't need to handle it.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

We should do better here by effetively "dereferencing" references to
the .toc (or the .got2) section, but that is much harder.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

With this change we can find more symbols hereby improving
the readability of the warnings.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

On i386 and MIPS, warn_sec_mismatch() sometimes fails to show
usefull symbol name.  This is because empty 'refsym' due to 0 r_addend
value.  This patch is to adjust r_addend value, consulting with
apply_relocate() routine in kernel code.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

There's a special .cranges section that is almost always generated,
with data being moved to the appropriate section by the linker at a later
stage.

To give a bit of background, sh64 has both a native SHmedia instruction
set (32-bit instructions) and SHcompact (which is compatability with
normal SH -- 16-bit, a massively reduced register set, etc.). code ranges
are emitted when we're using the 32-bit ABI, but not the 64-bit one.

It is a special staging section used solely by binutils where code with
different flags get placed (more specifically differing flags for input
and output sections), before being lazily merged by the linker.

The closest I've been able to find to documentation is:
  http://sources.redhat.com/cgi-bin/cvsweb.cgi/src/ld/emultempl/sh64elf.em?rev=1.10&content-type=text/x-cvsweb-markup&cvsroot=src

It's an array of 8-byte Elf32_CRange structure given in
  http://sources.redhat.com/cgi-bin/cvsweb.cgi/src/bfd/elf32-sh64.h?rev=1.4&content-type=text/x-cvsweb-markup&cvsroot=src
that describes for which ISA a range is used.

Silence the warnings by allowing references from .init.text to .cranges.

The following warnings are fixed:

WARNING: init/built-in.o(.cranges+0x0): Section mismatch: reference to .init.text:
WARNING: init/built-in.o(.cranges+0xa): Section mismatch: reference to .init.text:
WARNING: init/built-in.o(.cranges+0x14): Section mismatch: reference to .init.text:
WARNING: init/built-in.o(.cranges+0x1e): Section mismatch: reference to .init.text:
WARNING: init/built-in.o(.cranges+0x28): Section mismatch: reference to .init.text:
WARNING: init/built-in.o(.cranges+0x32): Section mismatch: reference to .init.text:
WARNING: kernel/built-in.o(.cranges+0x50): Section mismatch: reference to .init.text:
WARNING: kernel/built-in.o(.cranges+0x5a): Section mismatch: reference to .init.text:
WARNING: kernel/built-in.o(.cranges+0x64): Section mismatch: reference to .init.text:
WARNING: kernel/built-in.o(.cranges+0xfa): Section mismatch: reference to .init.text:
WARNING: kernel/built-in.o(.cranges+0x104): Section mismatch: reference to .init.text:
WARNING: kernel/built-in.o(.cranges+0x10e): Section mismatch: reference to .init.text:
WARNING: kernel/built-in.o(.cranges+0x14a): Section mismatch: reference to .init.text:
WARNING: kernel/built-in.o(.cranges+0x154): Section mismatch: reference to .init.text:
WARNING: kernel/built-in.o(.cranges+0x15e): Section mismatch: reference to .init.text:
WARNING: mm/built-in.o(.cranges+0x6e): Section mismatch: reference to .init.text:
WARNING: mm/built-in.o(.cranges+0x78): Section mismatch: reference to .init.text:
WARNING: mm/built-in.o(.cranges+0x82): Section mismatch: reference to .init.text:
WARNING: mm/built-in.o(.cranges+0xaa): Section mismatch: reference to .init.text:
WARNING: fs/built-in.o(.cranges+0x136): Section mismatch: reference to .init.text:
WARNING: fs/built-in.o(.cranges+0x140): Section mismatch: reference to .init.text:
WARNING: fs/built-in.o(.cranges+0x14a): Section mismatch: reference to .init.text:
WARNING: fs/built-in.o(.cranges+0x168): Section mismatch: reference to .init.text:
WARNING: fs/built-in.o(.cranges+0x1f4): Section mismatch: reference to .init.text:
WARNING: fs/built-in.o(.cranges+0x1fe): Section mismatch: reference to .init.text:
WARNING: net/built-in.o(.cranges+0x302): Section mismatch: reference to .init.text:
WARNING: net/built-in.o(.cranges+0x30c): Section mismatch: reference to .init.text:
WARNING: net/built-in.o(.cranges+0x316): Section mismatch: reference to .init.text:
WARNING: net/built-in.o(.cranges+0x3a2): Section mismatch: reference to .init.text:
WARNING: net/built-in.o(.cranges+0x3ac): Section mismatch: reference to .init.text:
WARNING: net/built-in.o(.cranges+0x4ce): Section mismatch: reference to .init.text:
WARNING: net/built-in.o(.cranges+0x4d8): Section mismatch: reference to .init.text:
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
Cc: Kaz Kojima <kkojima@rr.iij4u.or.jp>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

This reverts commit f892b7d4, which
totally broke the build on x86 with CONFIG_RELOCATABLE (which, as far as
I can tell, is the only case where it should even matter!) due to a
SIGSEGV in modpost.

Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

modpost had two cases hardcoded for mm/
Shift over to __init_refok and kill the
hardcoded function names in modpost.

This has the drawback that the functions
will always be kept no matter configuration.
With previous code the function were placed in
init section if configuration allowed it.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Kill a special case in modpost by introducing the
__init_refok marker.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Throughout the kernel there are a few legitimite references
to init or exit sections. Most of these are covered by the
patterns included in modpost but a few nees special attention.
To avoid hardcoding a lot of function names in modpost introduce
a marker so relevant function/data can be marked.
When modpost see a reference to a init/exit function from
a function/data marked no warning will be issued.

Idea from: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>

This patch fixes the following class of "Section mismatch" warnings when
building powerpc platforms.

WARNING: arch/powerpc/kernel/built-in.o - Section mismatch: reference to .init.data:.got2 from prom_entry (offset 0x0)
WARNING: arch/powerpc/platforms/built-in.o - Section mismatch: reference to .init.text:mpc8313_rdb_probe from .machine.desc after 'mach_mpc8313_rdb' (at offset 0x4)
....
Signed-off-by: NLi Yang <leoli@freescale.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

On i386, ARM and MIPS, warn_sec_mismatch() sometimes fails to show
usefull symbol name.  This is because empty 'refsym' due to 0 r_addend
value.  This patch is to adjust r_addend value, consulting with
apply_relocate() routine in kernel code.

Without this patch:
  MODPOST vmlinux
WARNING: init/built-in.o - Section mismatch: reference to .init.text: from .text between 'rest_init' (at offset 0xf4) and 'try_name'
WARNING: mm/built-in.o - Section mismatch: reference to .init.text: from .text between 'kmem_cache_create' (at offset 0x18a39) and 'cache_reap'
WARNING: mm/built-in.o - Section mismatch: reference to .init.text: from .text between 'kmem_cache_create' (at offset 0x18a6b) and 'cache_reap'

With this patch:
  MODPOST vmlinux
WARNING: mm/built-in.o - Section mismatch: reference to .init.text:set_up_list3s from .text between 'kmem_cache_create' (at offset 0x18a39) and 'cache_reap'
WARNING: mm/built-in.o - Section mismatch: reference to .init.text:set_up_list3s from .text between 'kmem_cache_create' (at offset 0x18a6b) and 'cache_reap'

Now modpost can detect "kernel_init" name (and whitelist it) and show
"set_up_list3s" name.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Change modpost section mismatch warnings to be less confusing;
model them on the binutils linker warnings which we all know how
to interpret.

Also, fix the wrong ordering of arguments for the final case -
fromsec and refsymname were reversed.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NAcked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

This will later allow an arch to add module specific information via linker
generated tables instead of poking directly in the module object structure.
Signed-off-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch is add white list into modpost.c for some functions and
ia64's section to fix section mismatchs.

  sparse_index_alloc() and zone_wait_table_init() calls bootmem allocator
  at boot time, and kmalloc/vmalloc at hotplug time. If config
  memory hotplug is on, there are references of bootmem allocater(init text)
  from them (normal text). This is cause of section mismatch.

  Bootmem is called by many functions and it must be
  used only at boot time. I think __init of them should keep for
  section mismatch check. So, I would like to register sparse_index_alloc()
  and zone_wait_table_init() into white list.

  In addition, ia64's .machvec section is function table of some platform
  dependent code. It is mixture of .init.text and normal text. These
  reference of __init functions are valid too.
Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Added on request from:  Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Cc:  Rusty Russell <rusty@rustcorp.com.au>

Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Some of modpost's warnings are fatal, and some are not.  Adopt the
compiler distinction between errors and warnings by calling merror()
for fatal diagnostics and warn() for non-fatal ones.
merror() was used as replacemtn for error() to avoid clash with glibc
Signed-off-by: NMatthew Wilcox <matthew@wil.cx>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

drivers/video/logo has references from .text to .init.data
but function is only used during early init.
So reference is OK and we do not want to warn about them =>
whitelist the reference.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

If modpost was called manually with filenames without '/'
then modpost would segfault.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Now where we do not pass vmlinux to modpost we started
to see section mismatch warnings from .pci_fixup.
Refactored code a little to include these in the
whitelist again.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

In init/main.c we have a reference from rest_init() to .init.text
which is intentional.
Rename the function 'init' to 'kernel_init' to make it a
kernel wide unique symbol and whitelist the reference.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

vmlinux does not contain relocation entries which is
used by the section mismatch checks.
Reported by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>

Use the individual objects as inputs to overcome
this limitation.
In modpost check the .o files and skip non-ELF files.
Signed-off-by: NSam Ravnborg <sam@ravnborg.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>

This patch stops "modpost" from issuing erroneous modpost warnings on ARM
builds, which it's been doing since since maybe last summer.  A canonical
example would be driver method table entries:

  WARNING: <path> - Section mismatch: reference to .exit.text:<name>_remove
	from .data after '$d' (at offset 0x4)

That "$d" symbol is generated by tools conformant with ARM ABI specs; in
this case it's a symbol **in the middle of** a "<name>_driver" struct.

The erroneous warnings appear to be issued because "modpost" whitelists
references from "<name>_driver" data into init and exit sections ...  but
doesn't know should also include those "$d" mapping symbols, which are not
otherwise associated with "<name>_driver" symbols.

This patch prevents the modpost symbol lookup code from ever returning
those mapping symbols, so it will return a whitelisted symbol instead.
Then things work as expected.

Now to revert various code-bloating "fixes" that got merged because of this
modpost bug....
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Roman Zippel <zippel@linux-m68k.org>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

o Entry startup_32 was in .text section but it was accessing some init
  data too and it prompts MODPOST to generate compilation warnings.

WARNING: vmlinux - Section mismatch: reference to .init.data:boot_params from
.text between '_text' (at offset 0xc0100029) and 'startup_32_smp'
WARNING: vmlinux - Section mismatch: reference to .init.data:boot_params from
.text between '_text' (at offset 0xc0100037) and 'startup_32_smp'
WARNING: vmlinux - Section mismatch: reference to
.init.data:init_pg_tables_end from .text between '_text' (at offset
0xc0100099) and 'startup_32_smp'

o Can't move startup_32 to .init.text as this entry point has to be at the
  start of bzImage. Hence moved startup_32 to a new section .text.head and
  instructed MODPOST to not to generate warnings if init data is being
  accessed from .text.head section. This code has been audited.

o SMP boot up code (startup_32_smp) can go into .init.text if CPU hotplug
  is not supported. Otherwise it generates more warnings

WARNING: vmlinux - Section mismatch: reference to .init.data:new_cpu_data from
.text between 'checkCPUtype' (at offset 0xc0100126) and 'is486'
WARNING: vmlinux - Section mismatch: reference to .init.data:new_cpu_data from
.text between 'checkCPUtype' (at offset 0xc0100130) and 'is486'
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NAndi Kleen <ak@suse.de>

parisc and parisc64 seem to name sections a little differently from other
targets.  parisc64 gives spurious warnings like:

WARNING: drivers/net/dummy.o - Section mismatch: reference to .init.text:dummy_setup from .data.rel.ro between '.LC1' (at offset 0x0) and '.LC6'

and parisc gives spurious warnings like:

WARNING: drivers/net/dummy.o - Section mismatch: reference to .init.text:dummy_setup from .rodata.cst4 between '.LC1' (at offset 0x0) and '.LC6'

Given the other comments in modpost.c, it seems that the best solution is
to move rodata down to the 'match at start of name' section and add
.data.rel.ro to the 'match entire name' section.

Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

o MODPOST generates warning on i386 if kernel is compiled with
  CONFIG_RELOCATABLE=y.

WARNING: vmlinux - Section mismatch: reference to .init.text:__init_begin from .text between 'free_initmem' (at offset 0xc0114fd3) and 'do_test_wp_bit'
WARNING: vmlinux - Section mismatch: reference to .init.text:_sinittext from .text between 'core_kernel_text' (at offset 0xc012aeae) and 'kernel_text_address'
WARNING: vmlinux - Section mismatch: reference to .init.text:_einittext from .text between 'core_kernel_text' (at offset 0xc012aeb7) and 'kernel_text_address'
WARNING: vmlinux - Section mismatch: reference to .init.text:_sinittext from .text between 'get_symbol_pos' (at offset 0xc0135776) and 'reset_iter'
WARNING: vmlinux - Section mismatch: reference to .init.text:_einittext from .text between 'get_symbol_pos' (at offset 0xc013577d) and 'reset_iter'

o These symbols (__init_begin, _sinittext, _einittext) belong to init
  section and generally represent a section boundary. These are special
  symbols in the sense that their size is zero and no memory is allocated
  for them in init section. Their addr and value are same. So even if
  we free the init section, it is ok to reference them.

o Whitelist access to such select symbols in MODPOST.
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@osdl.org>

o MODPOST generates warning for i386 if compiled with CONFIG_RELOCATABLE=y
  and serial console support is enabled.

o Serial console setup function, serial8250_console_setup(), is a non __init
  function and it calls functions which are of type __init().
  (uart_parse_options() and uart_set_options()). Assuming, setup will
  be called during init time, changing serial8250_console_setup() to __init.

o Adding one more pattern to modpost whitelist. Console drivers might
  have *_console structures containing references to setup functions which
  can be of __init type. Don't generate warnings for those.

WARNING: vmlinux - Section mismatch: reference to .init.text: from .data between 'serial8250_console' (at offset 0xc05a33d8) and 'serial8250_reg'
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@osdl.org>

Section .parainstructions should not warn about section mismatches.

WARNING: drivers/net/hamradio/scc.o - Section mismatch: reference to .exit.text: from .parainstructions after '' (at offset 0x0)
WARNING: drivers/net/hamradio/scc.o - Section mismatch: reference to .exit.text: from .parainstructions after '' (at offset 0x8)
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Andi Kleen <ak@suse.de>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

It turns out that the most called ops, by several orders of magnitude,
are the interrupt manipulation ops.  These are obvious candidates for
patching, so mark them up and create infrastructure for it.

The method used is that the ops structure has a patch function, which
is called for each place which needs to be patched: this returns a
number of instructions (the rest are NOP-padded).

Usually we can spare a register (%eax) for the binary patched code to
use, but in a couple of critical places in entry.S we can't: we make
the clobbers explicit at the call site, and manually clobber the
allowed registers in debug mode as an extra check.

And:

Don't abuse CONFIG_DEBUG_KERNEL, add CONFIG_DEBUG_PARAVIRT.

And:

AK:  Fix warnings in x86-64 alternative.c build

And:

AK: Fix compilation with defconfig

And:

^From: Andrew Morton <akpm@osdl.org>

Some binutlises still like to emit references to __stop_parainstructions and
__start_parainstructions.

And:

AK: Fix warnings about unused variables when PARAVIRT is disabled.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Signed-off-by: NZachary Amsden <zach@vmware.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>