one early crash on one 8 node 256g machine:

Command line: console=uart8250,io,0x3f8,115200n8 initrd=kernel.org/mydisk11_x86_64.gz rw root=/dev/ram0 debug initcall_debug apic=debug acpi.debug_level=0x0000000f pci=routeirq ip=dhcp load_ramdisk=1 ramdisk_size=131072 BOOT_IMAGE=kernel.org/bzImage_2.6.25_k8.1
BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009bc00 (usable)
 BIOS-e820: 000000000009bc00 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000e6000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 00000000dffe0000 (usable)
 BIOS-e820: 00000000dffe0000 - 00000000dffee000 (ACPI data)
 BIOS-e820: 00000000dffee000 - 00000000dffff050 (ACPI NVS)
 BIOS-e820: 00000000dffff050 - 00000000e0000000 (reserved)
 BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
 BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
 BIOS-e820: 00000000ff700000 - 0000000100000000 (reserved)
 BIOS-e820: 0000000100000000 - 0000004020000000 (usable)
Early serial console at I/O port 0x3f8 (options '115200n8')
console [uart0] enabled
end_pfn_map = 67239936
Kernel panic - not syncing: Duplicated early reservation d40000-e42000

Pid: 0, comm: swapper Not tainted 2.6.24-smp-g5a514e21-dirty #3

Call Trace:
 [<ffffffff80221545>] lapic_get_maxlvt+0x0/0x10
 [<ffffffff80221657>] clear_local_APIC+0x5/0xcf
 [<ffffffff80221726>] disable_local_APIC+0x5/0x17
 [<ffffffff8021fe16>] smp_send_stop+0x46/0x4c
 [<ffffffff80235293>] panic+0x94/0x13e
 [<ffffffff80bc3b03>] sctp_eps_proc_init+0x12/0x34
 [<ffffffff80b9f1c5>] reserve_early+0x30/0x6c
 [<ffffffff80803925>] init_memory_mapping+0x2cd/0x2dc
 [<ffffffff80b9dc01>] setup_arch+0x21f/0x44e
 [<ffffffff80b978be>] start_kernel+0x6f/0x2c7
 [<ffffffff80b971cc>] _sinittext+0x1cc/0x1d3

it turns out there is overlap between pgtable and bss...

in System.map we have
ffffffff80d40420 b rsi_table
ffffffff80d40620 B krb5_seq_lock
ffffffff80d40628 b i.20437
ffffffff80d40630 b xprt_rdma_inline_write_padding
ffffffff80d40638 b sunrpc_table_header
ffffffff80d40640 b zero
ffffffff80d40644 b min_memreg
ffffffff80d40648 b rpcrdma_tk_lock_g
ffffffff80d40650 B sctp_assocs_id_lock
ffffffff80d40658 B proc_net_sctp
ffffffff80d40660 B sctp_assocs_id
ffffffff80d40680 B sysctl_sctp_mem
ffffffff80d40690 B sysctl_sctp_rmem
ffffffff80d406a0 B sysctl_sctp_wmem
ffffffff80d406b0 b sctp_ctl_socket
ffffffff80d406b8 b sctp_pf_inet6_specific
ffffffff80d406c0 b sctp_pf_inet_specific
ffffffff80d406c8 b sctp_af_v4_specific
ffffffff80d406d0 b sctp_af_v6_specific
ffffffff80d406d8 b sctp_rand.33270
ffffffff80d406dc b sctp_memory_pressure
ffffffff80d406e0 b sctp_sockets_allocated
ffffffff80d406e4 b sctp_memory_allocated
ffffffff80d406e8 b sctp_sysctl_header
ffffffff80d406f0 b zero
ffffffff80d406f4 A __bss_stop
ffffffff80d406f4 A _end

need to round up table_start to PAGE_SIZE.

also make the panic more informative.
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This just adds the PCI IDs of AMD's family 10h and 11h CPU's northbridges to
k8topology discovery.
Signed-off-by: NJoachim Deguara <joachim.deguara@amd.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Acked-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Put appropriate pagetable update hooks in so that paravirt knows
what's going on in there.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Use a standard list threaded through page->lru for maintaining the pgd
list on PAE.  This is the same as 64-bit, and seems saner than using a
non-standard list via page->index.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

PAE mode requires that we reload cr3 in order to guarantee that
changes to the pgd will be noticed by the processor.  This means that
in principle pud_clear needs to reload cr3 every time.  However,
because reloading cr3 implies a tlb flush, we want to avoid it where
possible.

pud_clear() is only used in a couple of places:
 - in free_pmd_range(), when pulling down a range of process address space, and
 - huge_pmd_unshare()

In both cases, the calling code will do a a tlb flush anyway, so
there's no need to do it within pud_clear().

In free_pmd_range(), the pud_clear is immediately followed by
pmd_free_tlb(); we can hook that to make the mmu_gather do an
unconditional full flush to make sure cr3 gets reloaded.

In huge_pmd_unshare, it is followed by flush_tlb_range, which always
results in a full cr3-reload tlb flush.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: William Irwin <wli@holomorphy.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch adds a new configuration option, which adds support for a new
early_param which gets checked in arch/x86/kernel/setup_{32,64}.c:setup_arch()
to decide wether OHCI-1394 FireWire controllers should be initialized and
enabled for physical DMA access to allow remote debugging of early problems
like issues ACPI or other subsystems which are executed very early.

If the config option is not enabled, no code is changed, and if the boot
paramenter is not given, no new code is executed, and independent of that,
all new code is freed after boot, so the config option can be even enabled
in standard, non-debug kernels.

With specialized tools, it is then possible to get debugging information
from machines which have no serial ports (notebooks) such as the printk
buffer contents, or any data which can be referenced from global pointers,
if it is stored below the 4GB limit and even memory dumps of of the physical
RAM region below the 4GB limit can be taken without any cooperation from the
CPU of the host, so the machine can be crashed early, it does not matter.

In the extreme, even kernel debuggers can be accessed in this way. I wrote
a small kgdb module and an accompanying gdb stub for FireWire which allows
to gdb to talk to kgdb using remote remory reads and writes over FireWire.

An version of the gdb stub fore FireWire is able to read all global data
from a system which is running a a normal kernel without any kernel debugger,
without any interruption or support of the system's CPU. That way, e.g. the
task struct and so on can be read and even manipulated when the physical DMA
access is granted.

A HOWTO is included in this patch, in Documentation/debugging-via-ohci1394.txt
and I've put a copy online at
ftp://ftp.suse.de/private/bk/firewire/docs/debugging-via-ohci1394.txt

It also has links to all the tools which are available to make use of it
another copy of it is online at:
ftp://ftp.suse.de/private/bk/firewire/kernel/ohci1394_dma_early-v2.diffSigned-Off-By: NBernhard Kaindl <bk@suse.de>
Tested-By: NThomas Renninger <trenn@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

In x86 PAE mode, stop treating pmds as a special case.  Previously
they were always allocated and freed with the pgd.  The modifies the
code to be the same as 64-bit mode, where they are allocated on
demand.

This is a step on the way to unifying 32/64-bit pagetable allocation
as much as possible.

There is a complicating wart, however.  When you install a new
reference to a pmd in the pgd, the processor isn't guaranteed to see
it unless you reload cr3.  Since reloading cr3 also has the
side-effect of flushing the tlb, this is an expense that we want to
avoid whereever possible.

This patch simply avoids reloading cr3 unless the update is to the
current pagetable.  Later patches will optimise this further.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: William Irwin <wli@holomorphy.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The change from current to tsk in do_page_fault is safe as
this is set at the very beginning of the function.

Removes a likely() annotation from the 64-bit version, this
could have instead been added to 32-bit.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

When changing a kernel page from RO->RW, it's OK to leave stale TLB
entries around, since doing a global flush is expensive and they pose
no security problem.  They can, however, generate a spurious fault,
which we should catch and simply return from (which will have the
side-effect of reloading the TLB to the current PTE).

This can occur when running under Xen, because it frequently changes
kernel pages from RW->RO->RW to implement Xen's pagetable semantics.
It could also occur when using CONFIG_DEBUG_PAGEALLOC, since it avoids
doing a global TLB flush after changing page permissions.
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

On !PAE 32-bit, _PAGE_NX will be 0, making is_prefetch always
return early.  The test is sufficient on PAE as __supported_pte_mask
is updated in the same places as nx_enabled in init_32.c which also
takes disable_nx into account.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Unify includes in moved fault.c.

Modify Makefiles to pick up unified file.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Elimination of these ifdefs can be done in a unified file.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

It's about time to get on with unifying these files, elimination
of the ugly ifdefs can occur in the unified file.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

printk fixes. NOP in terms of functionality, but strings got
a bit larger due to the KERN_ markers that were added.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch fixes some bugs of EFI memory handing code.

- On x86_64, it is possible that EFI memory map can not be mapped via
  identity map, so efi_map_memmap is removed, just use early_ioremap.

- On i386, the EFI memory map mapping take effect cross paging_init,
  so it is not necessary to use efi_map_memmap.

- EFI memory map is unmapped in efi_enter_virtual_mode to avoid
  early_ioremap leak.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This patch makes reboot_type of BOOT_EFI is used on i386 too. Because
correpsonding reboot code of i386 and x86_64 is merged.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This changes the oops dumping format for page faults to
be similar between X86_32 and 64.

This is the first user of printk_address on X86_32.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

This will help when unifying the oops dumping code on 32/64
bit.  No functional changes.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Further towards unifying these files, add another helper
in same spirit as is_errata93.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Further towards unifying these files, add another helper
in same spirit as is_errata93.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Yes! A mere 120 c_p_a() fixing and rewriting patches later,
we are now confident that we can enable UC by default for
ioremap(), on x86 too.

Every other architectures was doing this already. Doing so
makes Linux more robust against MTRR mixups (which might go
unnoticed if BIOS writers test other OSs only - where PAT
might override bad MTRRs defaults).
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Cleanup the address calculations, which are necessary to identify the
high/low alias mappings of the kernel on 64 bit machines. Instead of
calling __pa/__va back and forth, calculate the physical address once
and base the other calculations on it. Add understandable constants so
we can use the already available within() helper. Also add comments,
which help mere mortals to understand what this code does.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

make CONFIG_DEBUG_PAGEALLOC universally available.

CONFIG_HIBERNATION and CONFIG_HUGETLBFS was disabling it, for no
particular reason.

If there are any unfixed bugs here we'll fix it, but do not disable
vital debugging facilities like that ..
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

debug incorrect/late access to init memory, by permanently unmapping
the init memory ranges. Depends on CONFIG_DEBUG_PAGEALLOC=y.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

It looks like a mismerge put the rodata self-check in the wrong spot; move
it to the right place after marking the .rodata section read only.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

only present ptes must be flushed.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

clflush is sufficient to be issued on one CPU. The invalidation is
broadcast throughout the coherence domain.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

clflush is an unordered operation with respect to other memory
traffic, including other CLFLUSH instructions. This needs proper
fencing with mfence.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The function name global_flush_tlb() suggests something different from
what the function really does. Rename it to cpa_flush_all(), which is an
understandable counterpart to cpa_flush_range().

no global visibility of the old API anymore.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use clflush on CPUs which support this.

clflush is only used when the page attribute operation has been
successful. On CPUs which do not support clflush and in the case of
error the old fashioned global_flush_tlb() is called.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Convert cpa_set and cpa_clear to call the new set_clr function.
Seperate out the debug helpers.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Create a set_and_clr function to avoid the duplicate loops. Allows
also to do combined operations for optimization.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

To avoid the modification of the flush code for the clflush
implementation, move the flush into the set and clear functions and
provide helper functions for the debugging code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Latest update; I now have 4 NX tests, but 2 fail so they're #if 0'd.
I also cleaned up the NX test code quite a bit, and got rid of the ugly
exception table sorting stuff.

From: Arjan van de Ven <arjan@linux.intel.com>

This patch adds testcases for the CONFIG_DEBUG_RODATA configuration option
as well as the NX CPU feature/mappings. Both testcases can move to tests/
once that patch gets merged into mainline.
(I'm half considering moving the rodata test into mm/init.c but I'll
wait with that until init.c is unified)

As part of this I had to fix a not-quite-right alignment in the vmlinux.lds.h
for the RODATA sections, which lead to 1 page less being marked read only.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>