Re: 2.6.9-rc2-mm2

Akinobu Mita
2004-09-23T18:01:59Z

> - Added the kexec-based crashdump code. This is the code which uses kexec
> to jump into a new mini-kernel when the main kernel crashes. Userspace
> code in that mini-kernel then dumps the main kernel's memory to disk.
> These new patches provide the bits and pieces which the mini-kernel needs
> to be able to get at the main kernel's memory.

Interesting feature.

> There seem to be no hints as to how to get all this working - that will
> come.

According to "Documentation/kdump.txt", we need to apply the following patches
to build "mini-kernel".

http://www.xmission.com/~ebiederm/files/kexec/2.6.8.1-kexec3/
broken-out/highbzImage.i386.patch
http://www.xmission.com/~ebiederm/files/kexec/2.6.8.1-kexec3/
broken-out/vmlinux-lds.i386.patch

But, Appling "arch/i386/kernel/vmlinux.lds.S" to 2.6.9-rc2-mm2 failed.

Someone who try to make mini-kernel against 2.6.9-rc2-m2, also need below patch.

--- 2.6-mm-kdump/arch/i386/kernel/vmlinux.lds.S.orig 2004-09-23 21:47:45.000000000 +0900
+++ 2.6-mm-kdump/arch/i386/kernel/vmlinux.lds.S 2004-09-24 00:13:58.012736264 +0900
@@ -2,133 +2,167 @@
* Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>;
*/

+#define __ASSEMBLY__ 1
+#include <asm/page.h>
+#define LOAD_OFFSET __PAGE_OFFSET
+
#include <asm-generic/vmlinux.lds.h>
#include <asm/thread_info.h>
-#include <asm/page.h>
+#include <asm/segment.h>

OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
OUTPUT_ARCH(i386)
-ENTRY(startup_32)
+ENTRY(phys_startup_32)
jiffies = jiffies_64;
SECTIONS
{
- . = __PAGE_OFFSET + 0x100000;
- /* read-only */
- _text = .; /* Text and read-only data */
- .text : {
- *(.text)
- SCHED_TEXT
- LOCK_TEXT
- *(.fixup)
- *(.gnu.warning)
+ . = LOAD_OFFSET + LOAD_ADDRESS;
+ phys_startup_32 = startup_32 - LOAD_OFFSET;
+
+ /* read-only */
+ _text = .; /* Text and read-only data */
+ .text : AT(ADDR(.text) - LOAD_OFFSET) {
+ *(.text)
+ SCHED_TEXT
+ LOCK_TEXT
+ *(.fixup)
+ *(.gnu.warning)
} = 0x9090

- _etext = .; /* End of text section */
+ _etext = .; /* End of text section */
+
+ . = ALIGN(16); /* Exception table */
+ __start___ex_table = .;
+ __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
+ *(__ex_table)
+ }
+ __stop___ex_table = .;
+
+ RODATA
+
+ /* writeable */
+ .data : AT(ADDR(.data) - LOAD_OFFSET) { /* Data */
+ *(.data)
+ CONSTRUCTORS
+ }
+
+ . = ALIGN(4096);
+ __nosave_begin = .;
+ .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
+ *(.data.nosave)
+ }
+ . = ALIGN(4096);
+ __nosave_end = .;
+
+ . = ALIGN(4096);
+ .data.page_aligned : AT(ADDR(.data.page_aligned) - LOAD_OFFSET) {
+ *(.data.idt)
+ }
+
+ . = ALIGN(32);
+ .data.cacheline_aligned : AT(ADDR(.data.cacheline_aligned) - LOAD_OFFSET) {
+ *(.data.cacheline_aligned)
+ }
+
+ _edata = .; /* End of data section */
+
+ . = ALIGN(THREAD_SIZE); /* init_task */
+ .data.init_task : AT(ADDR(.data.init_task) - LOAD_OFFSET) {
+ *(.data.init_task)
+ }
+
+ /* will be freed after init */
+ . = ALIGN(4096); /* Init code and data */
+ __init_begin = .;
+ .init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
+ _sinittext = .;
+ *(.init.text)
+ _einittext = .;
+ }
+ .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
+ *(.init.data)
+ }
+ . = ALIGN(16);
+ __setup_start = .;
+ .init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
+ *(.init.setup)
+ }
+ __setup_end = .;
+ __initcall_start = .;
+ .initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
+ *(.initcall1.init)
+ *(.initcall2.init)
+ *(.initcall3.init)
+ *(.initcall4.init)
+ *(.initcall5.init)
+ *(.initcall6.init)
+ *(.initcall7.init)
+ }
+ __initcall_end = .;
+ __con_initcall_start = .;
+ .con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
+ *(.con_initcall.init)
+ }
+ __con_initcall_end = .;
+ SECURITY_INIT
+ . = ALIGN(4);
+ __alt_instructions = .;
+ .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
+ *(.altinstructions)
+ }
+ __alt_instructions_end = .;
+ .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
+ *(.altinstr_replacement)
+ }
+ /* .exit.text is discard at runtime, not link time, to deal with references
+ from .altinstructions and .eh_frame */
+ .exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
+ *(.exit.text)
+ }
+ .exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
+ *(.exit.data)
+ }
+ . = ALIGN(4096);
+ __initramfs_start = .;
+ .init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
+ *(.init.ramfs)
+ }
+ __initramfs_end = .;
+ . = ALIGN(32);
+ __per_cpu_start = .;
+ .data.percpu : AT(ADDR(.data.percpu) - LOAD_OFFSET) {
+ *(.data.percpu)
+ }
+ __per_cpu_end = .;
+ . = ALIGN(4096);
+ __init_end = .;
+ /* freed after init ends here */
+
+ __bss_start = .; /* BSS */
+ .bss : AT(ADDR(.bss) - LOAD_OFFSET) {
+ *(.bss.page_aligned)
+ *(.bss)
+ }
+ . = ALIGN(4);
+ __bss_stop = .;
+
+ _end = . ;
+
+ /* This is where the kernel creates the early boot page tables */
+ . = ALIGN(4096);
+ pg0 = .;
+
+ /* Sections to be discarded */
+ /DISCARD/ : {
+ *(.exitcall.exit)
+ }

- . = ALIGN(16); /* Exception table */
- __start___ex_table = .;
- __ex_table : { *(__ex_table) }
- __stop___ex_table = .;
-
- RODATA
-
- /* writeable */
- .data : { /* Data */
- *(.data)
- CONSTRUCTORS
- }
-
- . = ALIGN(4096);
- __nosave_begin = .;
- .data_nosave : { *(.data.nosave) }
- . = ALIGN(4096);
- __nosave_end = .;
-
- . = ALIGN(4096);
- .data.page_aligned : { *(.data.idt) }
-
- . = ALIGN(32);
- .data.cacheline_aligned : { *(.data.cacheline_aligned) }
-
- _edata = .; /* End of data section */
-
- . = ALIGN(THREAD_SIZE); /* init_task */
- .data.init_task : { *(.data.init_task) }
-
- /* will be freed after init */
- . = ALIGN(4096); /* Init code and data */
- __init_begin = .;
- .init.text : {
- _sinittext = .;
- *(.init.text)
- _einittext = .;
- }
- .init.data : { *(.init.data) }
- . = ALIGN(16);
- __setup_start = .;
- .init.setup : { *(.init.setup) }
- __setup_end = .;
- __initcall_start = .;
- .initcall.init : {
- *(.initcall1.init)
- *(.initcall2.init)
- *(.initcall3.init)
- *(.initcall4.init)
- *(.initcall5.init)
- *(.initcall6.init)
- *(.initcall7.init)
- }
- __initcall_end = .;
- __con_initcall_start = .;
- .con_initcall.init : { *(.con_initcall.init) }
- __con_initcall_end = .;
- SECURITY_INIT
- . = ALIGN(4);
- __alt_instructions = .;
- .altinstructions : { *(.altinstructions) }
- __alt_instructions_end = .;
- .altinstr_replacement : { *(.altinstr_replacement) }
- /* .exit.text is discard at runtime, not link time, to deal with references
- from .altinstructions and .eh_frame */
- .exit.text : { *(.exit.text) }
- .exit.data : { *(.exit.data) }
- . = ALIGN(4096);
- __initramfs_start = .;
- .init.ramfs : { *(.init.ramfs) }
- __initramfs_end = .;
- . = ALIGN(32);
- __per_cpu_start = .;
- .data.percpu : { *(.data.percpu) }
- __per_cpu_end = .;
- . = ALIGN(4096);
- __init_end = .;
- /* freed after init ends here */
-
- __bss_start = .; /* BSS */
- .bss : {
- *(.bss.page_aligned)
- *(.bss)
- }
- . = ALIGN(4);
- __bss_stop = .;
-
- _end = . ;
-
- /* This is where the kernel creates the early boot page tables */
- . = ALIGN(4096);
- pg0 = .;
-
- /* Sections to be discarded */
- /DISCARD/ : {
- *(.exitcall.exit)
- }
-
- /* Stabs debugging sections. */
- .stab 0 : { *(.stab) }
- .stabstr 0 : { *(.stabstr) }
- .stab.excl 0 : { *(.stab.excl) }
- .stab.exclstr 0 : { *(.stab.exclstr) }
- .stab.index 0 : { *(.stab.index) }
- .stab.indexstr 0 : { *(.stab.indexstr) }
- .comment 0 : { *(.comment) }
+ /* Stabs debugging sections. */
+ .stab 0 : { *(.stab) }
+ .stabstr 0 : { *(.stabstr) }
+ .stab.excl 0 : { *(.stab.excl) }
+ .stab.exclstr 0 : { *(.stab.exclstr) }
+ .stab.index 0 : { *(.stab.index) }
+ .stab.indexstr 0 : { *(.stab.indexstr) }
+ .comment 0 : { *(.comment) }
}