On x86-64, kernel memory freed after init can be entirely unmapped instead
of just getting 'poisoned' by overwriting with a debug pattern.

On i386 and x86-64 (under CONFIG_DEBUG_RODATA), kernel text and bug table
can also be write-protected.

Compared to the first version, this one prevents re-creating deleted
mappings in the kernel image range on x86-64, if those got removed
previously. This, together with the original changes, prevents temporarily
having inconsistent mappings when cacheability attributes are being
changed on such pages (e.g. from AGP code). While on i386 such duplicate
mappings don't exist, the same change is done there, too, both for
consistency and because checking pte_present() before using various other
pte_XXX functions is a requirement anyway. At once, i386 code gets
adjusted to use pte_huge() instead of open coding this.

AK: split out cpa() changes
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

Due to an over aggressive optimizer gcc 4.2 cannot optimize away _proxy_pda
in all cases (counter intuitive, but true).  This breaks loading of some
modules.

The earlier workaround to just export a dummy symbol didn't work unfortunately
because the module code ignores exports with 0 value.

Make it 1 instead.
Signed-off-by: NAndi Kleen <ak@suse.de>

Cleanup and re-enable vsyscall gettimeofday using the generic clocksource
infrastructure.

[akpm@osdl.org: cleanup]
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Update all arch/*/kernel/vmlinux.lds.S to not include space for initramfs
when CONFIG_BLK_DEV_INITRAMFS is not selected.  This saves another 4 kbytes
on most platfoms (some reserve PAGE_SIZE for initramfs).
Signed-off-by: NJean-Paul Saman <jean-paul.saman@nxp.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It has caused more problems than it ever really solved, and is
apparently not getting cleaned up and fixed.  We can put it back when
it's stable and isn't likely to make warning or bug events worse.

In the meantime, enable frame pointers for more readable stack traces.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The new PDA code uses a dummy _proxy_pda variable to describe
memory references to the PDA. It is never referenced
in inline assembly, but exists as input/output arguments.
gcc 4.2 in some cases can CSE references to this which causes
unresolved symbols.  Define it to zero to avoid this.
Signed-off-by: NAndi Kleen <ak@suse.de>

This makes x86-64 use the generic BUG machinery.

The main advantage in using the generic BUG machinery for x86-64 is that
the inlined overhead of BUG is just the ud2a instruction; the file+line
information are no longer inlined into the instruction stream.  This
reduces cache pollution.
Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The .eh_frame section contents is never written to, so it can as well
benefit from CONFIG_DEBUG_RODATA.

Diff-ed against firstfloor tree.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o Explicitly align data segment to PAGE_SIZE boundary otherwise depending on
  config options and tool chain it might be placed on a non PAGE_SIZE aligned
  boundary and vmlinux loaders like kexec fail when they encounter a
  PT_LOAD type segment which is not aligned to PAGE_SIZE boundary.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

o Explicitly align data segment to PAGE_SIZE boundary otherwise depending on
  config options and tool chain it might be placed on a non PAGE_SIZE aligned
  boundary and vmlinux loaders like kexec fail when they encounter a
  PT_LOAD type segment which is not aligned to PAGE_SIZE boundary.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

Add a vmlinux.lds.h helper macro for defining the eight-level initcall table,
teach all the architectures to use it.

This is a prerequisite for a patch which performs initcall synchronisation for
multithreaded-probing.

Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
[ Added AVR32 as well ]
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

o A recent change to vmlinux.ld.S file broke kexec as now resulting vmlinux
  program headers are overlapping in physical address space.

o Now all the vsyscall related sections are placed after data and after
  that mostly init data sections are placed. To avoid physical overlap
  among phdrs, there are three possible solutions.
	- Place vsyscall sections also in data phdrs instead of user
	- move vsyscal sections after init data in bss.
	- create another phdrs say data.init and move all the sections
	  after vsyscall into this new phdr.

o This patch implements the third solution.
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Magnus Damm <magnus@valinux.co.jp>
Cc: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>

With 2.6.18-rc4-mm2, now wall_jiffies will always be the same as jiffies.
So we can kill wall_jiffies completely.

This is just a cleanup and logically should not change any real behavior
except for one thing: RTC updating code in (old) ppc and xtensa use a
condition "jiffies - wall_jiffies == 1".  This condition is never met so I
suppose it is just a bug.  I just remove that condition only instead of
kill the whole "if" block.

[heiko.carstens@de.ibm.com: s390 build fix and cleanup]
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Andi Kleen <ak@muc.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Hirokazu Takata <takata.hirokazu@renesas.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

[AK: This apparently broke some systems, but we need it to fix
a compile problem with old binutils and in theory the patch
is correct. So let's trying reenabling it again.]

o Currently bss segment is being placed somewhere in the middle (after .data)
  section and after bss lots of init section and data sections are coming.
  Is it intentional?

o One side affect of placing bss in the middle is that objcopy keeps the
  bss in raw binary image (vmlinux.bin) hence unnecessarily increasing
  the size of raw binary image. (In my case ~600K). It also increases
  the size of generated bzImage, though the increase is very small
  (896 bytes), probably a very high compression ratio for stream
  of zeros.

o This patch moves the bss at the end hence reducing the size of
  bzImage by 896 bytes and size of vmlinux.bin by 600K.

o This change benefits in the context of relocatable kernel patches. If
  kernel bss is not part of compressed data (vmlinux.bin) then it does
  not have to be decompressed and this area can be used by the decompressor
  for its execution hence keeping the memory requirements bounded and
  decompressor code does not stomp over any other data loaded beyond
  kernel image (As might be the case with bootloaders like kexec).
Signed-off-by: NVivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

Before 2.6.16 this was changed to work around code that accessed
CPUs not in the possible map. But that code should be all fixed now,
so mark it __initdata again.
Signed-off-by: NAndi Kleen <ak@suse.de>

This patch updates x86_64 linker script to pack any .note.* sections
into a PT_NOTE segment in the output file.

To do this, we tell ld that we need a PT_NOTE segment.  This requires
us to start explicitly mapping sections to segments, so we also need
to explicitly create PT_LOAD segments for text and data, and map the
sections to them appropriately.  Fortunately, each section will
default to its previous section's segment, so it doesn't take many
changes to vmlinux.lds.S.

The corresponding change is already made for i386 in -mm and I'd like
this patch to join it. The section to segment mappings do change as do
the segment flags so some time in -mm would be good for that reason as
well, just in case.

In particular .data and .bss move from the text segment to the data
segment and .data.cacheline_aligned .data.read_mostly are put in the
data segment instead of a separate one.

I think that it would be possible to exactly match the existing section
to segment mapping and flags but it would be a more intrusive change and
I'm not sure there is a reason for the existing layout other than it is
what you get by default if you don't explicitly specify something else.
If there is a reason for the existing layout then I will of course make
the more intrusive change. If there is no reason we could probably drop
the executable or writable flags from some segments but I don't know how
much attention is paid to them anyway so it might not be worth the
effort.

The vsyscall related sections need to go in a different segment to the
normal data segment and so I invented a "user" segment to contain them.
I believe this should appear to be another data segment as far as the
kernel is concerned so the flags are setup accordingly.

The notes will be used in the Xen paravirt_ops backend to provide
additional information to the domain builder. I am in the process of
converting the xen-unstable kernels and tools over to this scheme at the
moment to support this in the future.

It has been suggested to me that the notes segment should have flags 0
(i.e. not readable) since it is only used by the loader and is not used
at runtime. For now I went with a readable segment since that is what
the i386 patch uses.

AK: dropped NOTES addition right now because the needed infrastructure
for that is not merged yet
Signed-off-by: NIan Campbell <ian.campbell@xensource.com>
Signed-off-by: NAndi Kleen <ak@suse.de>

This patch adds a vgetcpu vsyscall, which depending on the CPU RDTSCP
capability uses either the RDTSCP or CPUID to obtain a CPU and node
numbers and pass them to the program.

AK: Lots of changes over Vojtech's original code:
Better prototype for vgetcpu()
It's better to pass the cpu / node numbers as separate arguments
to avoid mistakes when going from SMP to NUMA.
Also add a fast time stamp based cache using a user supplied
argument to speed things more up.
Use fast method from Chuck Ebbert to retrieve node/cpu from
GDT limit instead of CPUID
Made sure RDTSCP init is always executed after node is known.
Drop printk
Signed-off-by: NVojtech Pavlik <vojtech@suse.cz>
Signed-off-by: NAndi Kleen <ak@suse.de>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

These are the x86_64-specific pieces to enable reliable stack traces. The
only restriction with this is that it currently cannot unwind across the
interrupt->normal stack boundary, as that transition is lacking proper
annotation.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Changes are largely identical to the i386 version:

 * alternative #define are moved to the new alternative.h file.
 * one new elf section with pointers to the lock prefixes which can be
   nop'ed out for non-smp.
 * two new elf sections simliar to the "classic" alternatives to
   replace SMP code with simpler UP code.
 * fixup headers to use alternative.h instead of defining their own
   LOCK / LOCK_PREFIX macros.

The patch reuses the i386 version of the alternatives code to avoid code
duplication.  The code in alternatives.c was shuffled around a bit to
reduce the number of #ifdefs needed.  It also got some tweaks needed for
x86_64 (vsyscall page handling) and new features (noreplacement option
which was x86_64 only up to now).  Debug printk's are changed from
compile-time to runtime.

Loosely based on a early version from Bastian Blank <waldi@debian.org>
Signed-off-by: NGerd Hoffmann <kraxel@suse.de>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fixup the read mostly section to start at internode cacheline boundary.
Signed-off-by: NRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: NShai Fultheim <shai@scalex86.org>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch puts the infrastructure in place to allow for a reordering of
functions based inside the vmlinux. The general idea is that it is possible
to put all "common" functions into the first 2Mb of the code, so that they
are covered by one TLB entry. This as opposed to the current situation where
a typical vmlinux covers about 3.5Mb (on x86-64) and thus 2 TLB entries.

This is done by enabling the -ffunction-sections flag in gcc, which puts
each function in its own ELF section, so that the linker can then order them
in a way defined by the linker script.

As per previous discussions, Linus said he wanted a "static" list for this,
eg a list provided by the kernel tarbal, so that most people have the same
ordering at least. A script is provided to create this list based on
readprofile(1) output. The included list is provisional, and entirely biased
on my own testbox and me running a few kernel compiles and some other
things.

I think that to get to a better list we need to invite people to submit
their own profiles, and somehow add those all up and base the final list on
that. I'm willing to do that effort if this is ends up being the prefered
approach. Such an effort probably needs to be repeated like once a year or
so to adopt to the changing nature of the kernel.

Made it a CONFIG with default n because it increases link times
dramatically.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch puts the code from head.S in a special .bootstrap.text
section.

I'm working on a patch to reorder the functions in the kernel (I'll post
that later), but for x86-64 at least the kernel bootstrap requires that
the head.S functions are on the very first page/pages of the kernel
text.  This is understandable since the bootstrap is complex enough
already and not a problem at all, it just means they aren't allowed to
be reordered.  This patch puts these special functions into a separate
section to document this, and to guarantee this in the light of possibly
reordering the rest later.

(So this patch doesn't fix a bug per se, but makes things more robust by
making the order of these functions explicit)
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Hack for 2.6.16. In 2.6.17 all code that uses NR_CPUs should
be audited and changed to only touch possible CPUs.

Don't mark the reference per cpu data init data (so it stays
around after boot) and point all impossible CPUs to it. This way
they reference some valid - although shared memory. Usually
this is only initialization like INIT_LIST_HEADs and there
won't be races because these CPUs never run. Still somewhat hackish.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Align the start of the per-cpu section to the configured number of bytes in a
cache line.  This stops a BUG_ON() from triggering in load_module() when
DEFINE_PER_CPU() is used in a module and the section isn't cacheline-aligned.
Rusty also found this and sent a patch in a while ago
(http://lkml.org/lkml/2004/10/19/17), I don't know what came of that.
Signed-off-by: NZach Brown <zach.brown@oracle.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This might help on distributions that use a 32bit biarch compiler.

First pass -m64 by default.

Secondly add some more .code32s because at least the Ubuntu biarch
32bit as called by gcc doesn't seem to handle -m64 -m32 as generated
by the Makefile without such assistance.

And finally make sure the linker script can be preprocessed
with a 32bit cpp.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

As a follow-up to the introduction of CONFIG_UNWIND_INFO, this
separates the generation of frame unwind information for x86-64 from
that of full debug information.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Adding __initdata_* to asm-generic/sections.h
Replaces a lot of open coded externs in arch/x86_64/*
I had to change __bss_end to __bss_stop to match the other architectures.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use the new macros for x86_64 too.

Note that the current scripts includes different definitions; more exactly,
it only contains part of the DWARF2 sections and the .comment one from
Stabs. Shouldn't be a problem, anyway.

Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch contains the x86_64 architecture specific changes to prevent the
possible race conditions.
Signed-off-by: NPrasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is the second time this has happened: inserting a new section requires
that we adjust the arithmetic which is used to calculate the vsyscall page's
offset.

Cc: Christoph Lameter <christoph@lameter.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add a new section called ".data.read_mostly" for data items that are read
frequently and rarely written to like cpumaps etc.

If these maps are placed in the .data section then these frequenly read
items may end up in cachelines with data is is frequently updated.  In that
case all processors in an SMP system must needlessly reload the cachelines
again and again containing elements of those frequently used variables.

The ability to share these cachelines will allow each cpu in an SMP system
to keep local copies of those shared cachelines thereby optimizing
performance.
Signed-off-by: NAlok N Kataria <alokk@calsoftinc.com>
Signed-off-by: NShobhit Dayal <shobhit@calsoftinc.com>
Signed-off-by: NChristoph Lameter <christoph@scalex86.org>
Signed-off-by: NShai Fultheim <shai@scalex86.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The vmlinux on x86_64 does not report the correct physical address of
the kernel.  Instead in the physical address field it currently
reports the virtual address of the kernel.

This is patch is a bug fix that corrects vmlinux to report the
proper physical addresses.

This is potentially a help for crash dump analysis tools.

This definitiely allows bootloaders that load vmlinux as a standard
ELF executable.  Bootloaders directly loading vmlinux become of
practical importance when we consider the kexec on panic case.
Signed-off-by: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!