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13 commits

Author SHA1 Message Date
Olaf Hering
997c136f51 fs/proc/vmcore.c: add hook to read_from_oldmem() to check for non-ram pages
The balloon driver in a Xen guest frees guest pages and marks them as
mmio.  When the kernel crashes and the crash kernel attempts to read the
oldmem via /proc/vmcore a read from ballooned pages will generate 100%
load in dom0 because Xen asks qemu-dm for the page content.  Since the
reads come in as 8byte requests each ballooned page is tried 512 times.

With this change a hook can be registered which checks wether the given
pfn is really ram.  The hook has to return a value > 0 for ram pages, a
value < 0 on error (because the hypercall is not known) and 0 for non-ram
pages.

This will reduce the time to read /proc/vmcore.  Without this change a
512M guest with 128M crashkernel region needs 200 seconds to read it, with
this change it takes just 2 seconds.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-26 17:12:37 -07:00
Mika Westerberg
9833c39400 ARM: 6485/5: proc/vmcore - allow archs to override vmcore_elf_check_arch()
Allow architectures to redefine this macro if needed. This is useful for
example in architectures where 64-bit ELF vmcores are not supported.
Specifying zero vmcore_elf64_check_arch() allows compiler to optimize
away unnecessary parts of parse_crash_elf64_headers().

We also rename the macro to vmcore_elf64_check_arch() to reflect that it
is used for 64-bit vmcores only.

Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-11-30 13:39:55 +00:00
Alexey Dobriyan
405f55712d headers: smp_lock.h redux
* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
  It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

  This will make hardirq.h inclusion cheaper for every PREEMPT=n config
  (which includes allmodconfig/allyesconfig, BTW)

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-12 12:22:34 -07:00
Alexey Dobriyan
5aa140c2de proc: move /proc/vmcore creation to fs/proc/vmcore.c
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-10-23 18:51:22 +04:00
Simon Horman
85a0ee342e kdump: add is_vmcore_usable() and vmcore_unusable()
The usage of elfcorehdr_addr has changed recently such that being set to
ELFCORE_ADDR_MAX is used by is_kdump_kernel() to indicate if the code is
executing in a kernel executed as a crash kernel.

However, arch/ia64/kernel/setup.c:reserve_elfcorehdr will rest
elfcorehdr_addr to ELFCORE_ADDR_MAX on error, which means any subsequent
calls to is_kdump_kernel() will return 0, even though they should return
1.

Ok, at this point in time there are no subsequent calls, but I think its
fair to say that there is ample scope for error or at the very least
confusion.

This patch add an extra state, ELFCORE_ADDR_ERR, which indicates that
elfcorehdr_addr was passed on the command line, and thus execution is
taking place in a crashdump kernel, but vmcore can't be used for some
reason.  This is tested for using is_vmcore_usable() and set using
vmcore_unusable().  A subsequent patch makes use of this new code.

To summarise, the states that elfcorehdr_addr can now be in are as follows:

ELFCORE_ADDR_MAX: not a crashdump kernel
ELFCORE_ADDR_ERR: crashdump kernel but vmcore is unusable
any other value:  crash dump kernel and vmcore is usable

Signed-off-by: Simon Horman <horms@verge.net.au>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:40 -07:00
Vivek Goyal
57cac4d188 kdump: make elfcorehdr_addr independent of CONFIG_PROC_VMCORE
o elfcorehdr_addr is used by not only the code under CONFIG_PROC_VMCORE
  but also by the code which is not inside CONFIG_PROC_VMCORE.  For
  example, is_kdump_kernel() is used by powerpc code to determine if
  kernel is booting after a panic then use previous kernel's TCE table.
  So even if CONFIG_PROC_VMCORE is not set in second kernel, one should be
  able to correctly determine that we are booting after a panic and setup
  calgary iommu accordingly.

o So remove the assumption that elfcorehdr_addr is under
  CONFIG_PROC_VMCORE.

o Move definition of elfcorehdr_addr to arch dependent crash files.
  (Unfortunately crash dump does not have an arch independent file
  otherwise that would have been the best place).

o kexec.c is not the right place as one can Have CRASH_DUMP enabled in
  second kernel without KEXEC being enabled.

o I don't see sh setup code parsing the command line for
  elfcorehdr_addr.  I am wondering how does vmcore interface work on sh.
  Anyway, I am atleast defining elfcoredhr_addr so that compilation is not
  broken on sh.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Simon Horman <horms@verge.net.au>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:39 -07:00
Ingo Molnar
36ac26171a crashdump: fix undefined reference to `elfcorehdr_addr'
fix build bug introduced by 95b68dec0d "calgary iommu: use the first
kernels TCE tables in kdump":

arch/x86/kernel/built-in.o: In function `calgary_iommu_init':
(.init.text+0x8399): undefined reference to `elfcorehdr_addr'
arch/x86/kernel/built-in.o: In function `calgary_iommu_init':
(.init.text+0x856c): undefined reference to `elfcorehdr_addr'
arch/x86/kernel/built-in.o: In function `detect_calgary':
(.init.text+0x8c68): undefined reference to `elfcorehdr_addr'
arch/x86/kernel/built-in.o: In function `detect_calgary':
(.init.text+0x8d0c): undefined reference to `elfcorehdr_addr'

make elfcorehdr_addr a generally available symbol.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-26 11:26:23 +02:00
Chandru
95b68dec0d calgary iommu: use the first kernels TCE tables in kdump
kdump kernel fails to boot with calgary iommu and aacraid driver on a x366
box.  The ongoing dma's of aacraid from the first kernel continue to exist
until the driver is loaded in the kdump kernel.  Calgary is initialized
prior to aacraid and creation of new tce tables causes wrong dma's to
occur.  Here we try to get the tce tables of the first kernel in kdump
kernel and use them.  While in the kdump kernel we do not allocate new tce
tables but instead read the base address register contents of calgary
iommu and use the tables that the registers point to.  With these changes
the kdump kernel and hence aacraid now boots normally.

Signed-off-by: Chandru Siddalingappa <chandru@in.ibm.com>
Acked-by: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:41 -07:00
Ian Campbell
79e030114a [PATCH] i386: Allow i386 crash kernels to handle x86_64 dumps
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: Ian Campbell <ian.campbell@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Vivek 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: Andrew Morton <akpm@linux-foundation.org>
2007-05-02 19:27:09 +02:00
Arjan van de Ven
4b6f5d20b0 [PATCH] Make most file operations structs in fs/ const
This is a conversion to make the various file_operations structs in fs/
const.  Basically a regexp job, with a few manual fixups

The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 09:16:06 -08:00
Vivek Goyal
666bfddbe8 [PATCH] kdump: Access dump file in elf format (/proc/vmcore)
From: "Vivek Goyal" <vgoyal@in.ibm.com>

o Support for /proc/vmcore interface. This interface exports elf core image
  either in ELF32 or ELF64 format, depending on the format in which elf headers
  have been stored by crashed kernel.
o Added support for CONFIG_VMCORE config option.
o Removed the dependency on /proc/kcore.

From: "Eric W. Biederman" <ebiederm@xmission.com>

This patch has been refactored to more closely match the prevailing style in
the affected files.  And to clearly indicate the dependency between
/proc/kcore and proc/vmcore.c

From: Hariprasad Nellitheertha <hari@in.ibm.com>

This patch contains the code that provides an ELF format interface to the
previous kernel's memory post kexec reboot.

Signed off by Hariprasad Nellitheertha <hari@in.ibm.com>
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:53 -07:00
Vivek Goyal
2030eae52b [PATCH] Retrieve elfcorehdr address from command line
This patch adds support for retrieving the address of elf core header if one
is passed in command line.

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:53 -07:00
Vivek Goyal
60e64d46a5 [PATCH] kdump: Routines for copying dump pages
This patch provides the interfaces necessary to read the dump contents,
treating it as a high memory device.

Signed off by Hariprasad Nellitheertha <hari@in.ibm.com>
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:53 -07:00