[patch 0/3] Reflect recent changes in kdump documentation

[patch 0/3] Reflect recent changes in kdump documentation

[Bernhard Walle]

This patch series reflects some recent changes that have been made on kdump
also in the documentation. See the description of the patches itself.

Signed-off-by: Bernhard Walle <bwalle@suse.de>

-- 

[patch 1/3] Express relocatability of kernel on x86_64 in documentation

[Bernhard Walle]

[-- Attachment #1: crashkernel-relocatable --]
[-- Type: text/plain, Size: 2865 bytes --]

This patch adapts the Documentation/kdump/kdump.txt file to express the fact
that the x86_64 kernel is now also relocatable. This makes i386 and x86_64 now
behave the same, simplifying the documentation.


Signed-off-by: Bernhard Walle <bwalle@suse.de>

---
 Documentation/kdump/kdump.txt |   35 ++++++-----------------------------
 1 file changed, 6 insertions(+), 29 deletions(-)

--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -159,16 +159,17 @@ Dump-capture kernel config options (Arch
    CONFIG_PROC_VMCORE=y
    (CONFIG_PROC_VMCORE is set by default when CONFIG_CRASH_DUMP is selected.)
 
-Dump-capture kernel config options (Arch Dependent, i386)
---------------------------------------------------------
-1) On x86, enable high memory support under "Processor type and
+Dump-capture kernel config options (Arch Dependent, i386 and x86_64)
+--------------------------------------------------------------------
+
+1) On i386, enable high memory support under "Processor type and
    features":
 
    CONFIG_HIGHMEM64G=y
    or
    CONFIG_HIGHMEM4G
 
-2) On x86 and x86_64, disable symmetric multi-processing support
+2) On i386 and x86_64, disable symmetric multi-processing support
    under "Processor type and features":
 
    CONFIG_SMP=n
@@ -203,28 +204,6 @@ Dump-capture kernel config options (Arch
 5) Make and install the kernel and its modules. DO NOT add this kernel
    to the boot loader configuration files.
 
-Dump-capture kernel config options (Arch Dependent, x86_64)
-----------------------------------------------------------
-1) On x86 and x86_64, disable symmetric multi-processing support
-   under "Processor type and features":
-
-   CONFIG_SMP=n
-
-   (If CONFIG_SMP=y, then specify maxcpus=1 on the kernel command line
-   when loading the dump-capture kernel, see section "Load the Dump-capture
-   Kernel".)
-
-2) Use a suitable value for "Physical address where the kernel is
-   loaded" (under "Processor type and features"). This only appears when
-   "kernel crash dumps" is enabled. By default this value is 0x1000000
-   (16MB). It should be the same as X in the "crashkernel=Y@X" boot
-   parameter.
-
-   For x86_64, normally "CONFIG_PHYSICAL_START=0x1000000".
-
-3) Make and install the kernel and its modules. DO NOT add this kernel
-   to the boot loader configuration files.
-
 Dump-capture kernel config options (Arch Dependent, ppc64)
 ----------------------------------------------------------
 
@@ -282,11 +261,9 @@ Based on the architecture and type of im
 can choose to load the uncompressed vmlinux or compressed bzImage/vmlinuz
 of dump-capture kernel. Following is the summary.
 
-For i386:
+For i386 and x86_64:
 	- Use vmlinux if kernel is not relocatable.
 	- Use bzImage/vmlinuz if kernel is relocatable.
-For x86_64:
-	- Use vmlinux
 For ppc64:
 	- Use vmlinux
 For ia64:

-- 

Re: [patch 1/3] Express relocatability of kernel on x86_64 in documentation

[Randy Dunlap]

On Sun, 09 Sep 2007 10:06:21 +0200 Bernhard Walle wrote:

> This patch adapts the Documentation/kdump/kdump.txt file to express the fact
> that the x86_64 kernel is now also relocatable. This makes i386 and x86_64 now
> behave the same, simplifying the documentation.
> 
> 
> Signed-off-by: Bernhard Walle <bwalle@suse.de>

Hi,
Can we also please reconcile the CRASH_DUMP Kconfig help text?
I.e., it says

  The crash dump kernel must be compiled
  to a memory address not used by the main kernel or BIOS using
  PHYSICAL_START.

but this ignores the use of RELOCATABLE, right?


---
From: Randy Dunlap <randy.dunlap@oracle.com>

Update help text for CONFIG_CRASH_DUMP.
Fix typos in CONFIG_RELOCATABLE.
Use tab + 2 spaces for indentation on all lines.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
---
 arch/i386/Kconfig   |   17 +++++++++--------
 arch/x86_64/Kconfig |   21 +++++++++++----------
 2 files changed, 20 insertions(+), 18 deletions(-)

--- linux-2.6.23-rc5-git1.orig/arch/i386/Kconfig
+++ linux-2.6.23-rc5-git1/arch/i386/Kconfig
@@ -820,12 +820,13 @@ config CRASH_DUMP
 	depends on HIGHMEM
 	help
 	  Generate crash dump after being started by kexec.
-          This should be normally only set in special crash dump kernels
+	  This should be normally only set in special crash dump kernels
 	  which are loaded in the main kernel with kexec-tools into
 	  a specially reserved region and then later executed after
 	  a crash by kdump/kexec. The crash dump kernel must be compiled
-          to a memory address not used by the main kernel or BIOS using
-          PHYSICAL_START.
+	  to a memory address not used by the main kernel or BIOS using
+	  PHYSICAL_START, or it must be built as a relocatable image
+	  (CONFIG_RELOCATABLE=y).
 	  For more details see Documentation/kdump/kdump.txt
 
 config PHYSICAL_START
@@ -871,17 +872,17 @@ config PHYSICAL_START
 	  Don't change this unless you know what you are doing.
 
 config RELOCATABLE
-	bool "Build a relocatable kernel(EXPERIMENTAL)"
+	bool "Build a relocatable kernel (EXPERIMENTAL)"
 	depends on EXPERIMENTAL
 	help
 	  This builds a kernel image that retains relocation information
-          so it can be loaded someplace besides the default 1MB.
+	  so it can be loaded someplace besides the default 1MB.
 	  The relocations tend to make the kernel binary about 10% larger,
-          but are discarded at runtime.
+	  but are discarded at runtime.
 
 	  One use is for the kexec on panic case where the recovery kernel
-          must live at a different physical address than the primary
-          kernel.
+	  must live at a different physical address than the primary
+	  kernel.
 
 config PHYSICAL_ALIGN
 	hex "Alignment value to which kernel should be aligned"
--- linux-2.6.23-rc5-git1.orig/arch/x86_64/Kconfig
+++ linux-2.6.23-rc5-git1/arch/x86_64/Kconfig
@@ -575,17 +575,18 @@ config CRASH_DUMP
 	bool "kernel crash dumps (EXPERIMENTAL)"
 	depends on EXPERIMENTAL
 	help
-          Generate crash dump after being started by kexec.
-          This should be normally only set in special crash dump kernels
-          which are loaded in the main kernel with kexec-tools into
-          a specially reserved region and then later executed after
-          a crash by kdump/kexec. The crash dump kernel must be compiled
+	  Generate crash dump after being started by kexec.
+	  This should be normally only set in special crash dump kernels
+	  which are loaded in the main kernel with kexec-tools into
+	  a specially reserved region and then later executed after
+	  a crash by kdump/kexec. The crash dump kernel must be compiled
 	  to a memory address not used by the main kernel or BIOS using
-	  PHYSICAL_START.
-          For more details see Documentation/kdump/kdump.txt
+	  PHYSICAL_START, or it must be built as a relocatable image
+	  (CONFIG_RELOCATABLE=y).
+	  For more details see Documentation/kdump/kdump.txt
 
 config RELOCATABLE
-	bool "Build a relocatable kernel(EXPERIMENTAL)"
+	bool "Build a relocatable kernel (EXPERIMENTAL)"
 	depends on EXPERIMENTAL
 	help
 	  Builds a relocatable kernel. This enables loading and running
@@ -596,8 +597,8 @@ config RELOCATABLE
 	  must live at a different physical address than the primary
 	  kernel.
 
-	  Note: If CONFIG_RELOCATABLE=y, then kernel run from the address
-	  it has been loaded at and compile time physical address
+	  Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
+	  it has been loaded at and the compile time physical address
 	  (CONFIG_PHYSICAL_START) is ignored.
 
 config PHYSICAL_START

[patch 2/3] Express new ELF32 mechanisms in documentation

[Bernhard Walle]

[-- Attachment #1: crashkernel-elf32 --]
[-- Type: text/plain, Size: 1442 bytes --]

This patch reflects the
http://git.kernel.org/?p=linux/kernel/git/horms/kexec-tools-testing.git;a=commit;h=b9c3648e690ad0dad12389659673206213a09760
change in kexec-tools-testing also now in the kernel documentation.


Signed-off-by: Bernhard Walle <bwalle@suse.de>

---
 Documentation/kdump/kdump.txt |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -301,11 +301,13 @@ For ppc64:
 Notes on loading the dump-capture kernel:
 
 * By default, the ELF headers are stored in ELF64 format to support
-  systems with more than 4GB memory. The --elf32-core-headers option can
-  be used to force the generation of ELF32 headers. This is necessary
-  because GDB currently cannot open vmcore files with ELF64 headers on
-  32-bit systems. ELF32 headers can be used on non-PAE systems (that is,
-  less than 4GB of memory).
+  systems with more than 4GB memory. On i386, kexec automatically checks if
+  the physical RAM size exceeds the 4 GB limit and if not, uses ELF32.
+  So, on non-PAE systems, ELF32 is always used.
+
+  The --elf32-core-headers option can be used to force the generation of ELF32
+  headers. This is necessary because GDB currently cannot open vmcore files
+  with ELF64 headers on 32-bit systems.
 
 * The "irqpoll" boot parameter reduces driver initialization failures
   due to shared interrupts in the dump-capture kernel.

-- 

[patch 3/3] Add reset_devices to the recommended parameters

[Bernhard Walle]

[-- Attachment #1: crashkernel-reset_devices --]
[-- Type: text/plain, Size: 857 bytes --]

This patch adds the "reset_devices" option (that's used only by one device
driver for now) to the recommended list of command line parameters for kdump.

Meaning (Documentation/kernel-parameters.txt):
    reset_devices   [KNL] Force drivers to reset the underlying device
                    during initialization.


Signed-off-by: Bernhard Walle <bwalle@suse.de>

---
 Documentation/kdump/kdump.txt |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -292,10 +292,10 @@ Following are the arch specific command 
 loading dump-capture kernel.
 
 For i386, x86_64 and ia64:
-	"1 irqpoll maxcpus=1"
+	"1 irqpoll maxcpus=1 reset_devices"
 
 For ppc64:
-	"1 maxcpus=1 noirqdistrib"
+	"1 maxcpus=1 noirqdistrib reset_devices"
 
 
 Notes on loading the dump-capture kernel:

--