[PATCH][1/4] kexec based dump: Loading kernel from non-default offset
From: Hariprasad Nellitheertha
Date: Thu Oct 21 2004 - 05:53:13 EST
This patch makes it possible for us to load i386 kernels
from non-default physical addresses.
Regards, Hari
Signed-off-by: Hariprasad Nellitheertha <hari@xxxxxxxxxx>
---
linux-old-hari/arch/i386/Kconfig | 10 ++++
linux-old-hari/arch/i386/boot/compressed/head.S | 6 +-
linux-old-hari/arch/i386/boot/compressed/misc.c | 7 +-
linux-old-hari/arch/i386/kernel/vmlinux.lds.S | 56 +++++++++++++----------
linux-old-hari/include/asm-generic/vmlinux.lds.h | 2
linux-old-hari/include/asm-i386/segment.h | 2
6 files changed, 54 insertions(+), 29 deletions(-)
diff -puN arch/i386/Kconfig~kd-kern-offset arch/i386/Kconfig
--- linux-old/arch/i386/Kconfig~kd-kern-offset 2004-10-19 19:00:17.000000000 +0530
+++ linux-old-hari/arch/i386/Kconfig 2004-10-19 19:03:47.000000000 +0530
@@ -882,6 +882,16 @@ config REGPARM
source "drivers/perfctr/Kconfig"
+config KERN_PHYS_OFFSET
+ int "Physical address where the kernel is loaded (1-112)MB"
+ range 1 112
+ default "1"
+ help
+ This gives the physical address where the kernel is loaded.
+ Primarily used in the case of kexec on panic where the
+ recovery kernel needs to run at a different address than
+ the panic-ed kernel.
+
config KEXEC
bool "kexec system call (EXPERIMENTAL)"
depends on EXPERIMENTAL
diff -puN arch/i386/boot/compressed/head.S~kd-kern-offset arch/i386/boot/compressed/head.S
--- linux-old/arch/i386/boot/compressed/head.S~kd-kern-offset 2004-10-19 19:04:55.000000000 +0530
+++ linux-old-hari/arch/i386/boot/compressed/head.S 2004-10-19 19:06:02.000000000 +0530
@@ -74,7 +74,7 @@ startup_32:
popl %esi # discard address
popl %esi # real mode pointer
xorl %ebx,%ebx
- ljmp $(__BOOT_CS), $0x100000
+ ljmp $(__BOOT_CS), $KERN_PHYS_OFFSET
/*
* We come here, if we were loaded high.
@@ -99,7 +99,7 @@ startup_32:
popl %ecx # lcount
popl %edx # high_buffer_start
popl %eax # hcount
- movl $0x100000,%edi
+ movl $KERN_PHYS_OFFSET,%edi
cli # make sure we don't get interrupted
ljmp $(__BOOT_CS), $0x1000 # and jump to the move routine
@@ -124,5 +124,5 @@ move_routine_start:
movsl
movl %ebx,%esi # Restore setup pointer
xorl %ebx,%ebx
- ljmp $(__BOOT_CS), $0x100000
+ ljmp $(__BOOT_CS), $KERN_PHYS_OFFSET
move_routine_end:
diff -puN arch/i386/boot/compressed/misc.c~kd-kern-offset arch/i386/boot/compressed/misc.c
--- linux-old/arch/i386/boot/compressed/misc.c~kd-kern-offset 2004-10-19 19:04:55.000000000 +0530
+++ linux-old-hari/arch/i386/boot/compressed/misc.c 2004-10-19 19:08:07.000000000 +0530
@@ -14,6 +14,7 @@
#include <linux/tty.h>
#include <video/edid.h>
#include <asm/io.h>
+#include <asm/segment.h>
/*
* gzip declarations
@@ -309,7 +310,7 @@ static void setup_normal_output_buffer(v
#else
if ((RM_ALT_MEM_K > RM_EXT_MEM_K ? RM_ALT_MEM_K : RM_EXT_MEM_K) < 1024) error("Less than 2MB of memory");
#endif
- output_data = (char *)0x100000; /* Points to 1M */
+ output_data = (char *)KERN_PHYS_OFFSET; /* Points to 1M */
free_mem_end_ptr = (long)real_mode;
}
@@ -334,8 +335,8 @@ static void setup_output_buffer_if_we_ru
low_buffer_size = low_buffer_end - LOW_BUFFER_START;
high_loaded = 1;
free_mem_end_ptr = (long)high_buffer_start;
- if ( (0x100000 + low_buffer_size) > ((ulg)high_buffer_start)) {
- high_buffer_start = (uch *)(0x100000 + low_buffer_size);
+ if ( (KERN_PHYS_OFFSET + low_buffer_size) > ((ulg)high_buffer_start)) {
+ high_buffer_start = (uch *)(KERN_PHYS_OFFSET + low_buffer_size);
mv->hcount = 0; /* say: we need not to move high_buffer */
}
else mv->hcount = -1;
diff -puN include/asm-i386/segment.h~kd-kern-offset include/asm-i386/segment.h
--- linux-old/include/asm-i386/segment.h~kd-kern-offset 2004-10-19 19:09:19.000000000 +0530
+++ linux-old-hari/include/asm-i386/segment.h 2004-10-19 19:09:59.000000000 +0530
@@ -95,4 +95,6 @@
*/
#define IDT_ENTRIES 256
+#define KERN_PHYS_OFFSET (CONFIG_KERN_PHYS_OFFSET * 0x100000)
+
#endif
diff -puN include/asm-generic/vmlinux.lds.h~kd-kern-offset include/asm-generic/vmlinux.lds.h
--- linux-old/include/asm-generic/vmlinux.lds.h~kd-kern-offset 2004-10-19 19:09:19.000000000 +0530
+++ linux-old-hari/include/asm-generic/vmlinux.lds.h 2004-10-19 19:21:09.000000000 +0530
@@ -70,7 +70,7 @@
}
#define SECURITY_INIT \
- .security_initcall.init : { \
+ .security_initcall.init : AT(ADDR(.security_initcall.init) - LOAD_OFFSET) {\
VMLINUX_SYMBOL(__security_initcall_start) = .; \
*(.security_initcall.init) \
VMLINUX_SYMBOL(__security_initcall_end) = .; \
diff -puN arch/i386/kernel/vmlinux.lds.S~kd-kern-offset arch/i386/kernel/vmlinux.lds.S
--- linux-old/arch/i386/kernel/vmlinux.lds.S~kd-kern-offset 2004-10-19 19:33:47.000000000 +0530
+++ linux-old-hari/arch/i386/kernel/vmlinux.lds.S 2004-10-19 19:43:27.000000000 +0530
@@ -2,20 +2,24 @@
* Written by Martin Mares <mj@xxxxxxxxxxxxxxxxxxxxxxxx>;
*/
+#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;
+ . = LOAD_OFFSET + KERN_PHYS_OFFSET;
+ phys_startup_32 = startup_32 - LOAD_OFFSET;
/* read-only */
_text = .; /* Text and read-only data */
- .text : {
+ .text : AT(ADDR(.text) - LOAD_OFFSET) {
*(.text)
SCHED_TEXT
LOCK_TEXT
@@ -27,49 +31,51 @@ SECTIONS
. = ALIGN(16); /* Exception table */
__start___ex_table = .;
- __ex_table : { *(__ex_table) }
+ __ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) { *(__ex_table) }
__stop___ex_table = .;
RODATA
/* writeable */
- .data : { /* Data */
+ .data : AT(ADDR(.data) - LOAD_OFFSET) { /* Data */
*(.data)
CONSTRUCTORS
}
. = ALIGN(4096);
__nosave_begin = .;
- .data_nosave : { *(.data.nosave) }
+ .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) { *(.data.nosave) }
. = ALIGN(4096);
__nosave_end = .;
. = ALIGN(4096);
- .data.page_aligned : { *(.data.idt) }
+ .data.page_aligned : AT(ADDR(.data.page_aligned) - LOAD_OFFSET) { *(.data.idt) }
. = ALIGN(32);
- .data.cacheline_aligned : { *(.data.cacheline_aligned) }
+ .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 : { *(.data.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 : {
+ .init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
_sinittext = .;
*(.init.text)
_einittext = .;
}
- .init.data : { *(.init.data) }
+ .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) { *(.init.data) }
. = ALIGN(16);
__setup_start = .;
- .init.setup : { *(.init.setup) }
+ .init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) { *(.init.setup) }
__setup_end = .;
__initcall_start = .;
- .initcall.init : {
+ .initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
*(.initcall1.init)
*(.initcall2.init)
*(.initcall3.init)
@@ -80,32 +86,38 @@ SECTIONS
}
__initcall_end = .;
__con_initcall_start = .;
- .con_initcall.init : { *(.con_initcall.init) }
+ .con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
+ *(.con_initcall.init)
+ }
__con_initcall_end = .;
SECURITY_INIT
. = ALIGN(4);
__alt_instructions = .;
- .altinstructions : { *(.altinstructions) }
- __alt_instructions_end = .;
- .altinstr_replacement : { *(.altinstr_replacement) }
+ .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 : { *(.exit.text) }
- .exit.data : { *(.exit.data) }
+ .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 : { *(.init.ramfs) }
+ .init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) { *(.init.ramfs) }
__initramfs_end = .;
. = ALIGN(32);
__per_cpu_start = .;
- .data.percpu : { *(.data.percpu) }
+ .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 : {
+ .bss : AT(ADDR(.bss) - LOAD_OFFSET) {
*(.bss.page_aligned)
*(.bss)
}
_