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From: David W. <dw...@in...> - 2001-09-03 16:25:35
|
When we load a zImage, we load it to 0x210000 and it decompresses the real
kernel image to 0x1000.
The parameter block is in the first page of memory, and the zImage
decompression code doesn't touch it. The bootloader is expected to load the
zImage to 0x210000 and the parameters to 0x0.
Does anyone actually pass parameters to the kernel this way? I'd like to
change the address at which the zImage expects the parameter block to be
loaded - to load it to the beginning of the zImage just as we would
normally load it at the beginning of a vmlinux.
The attached patch does this - moves the entry point of the zImage to
0x211000 and makes it copy the parameter block from 0x210000 to 0 after
decompressing the kernel image to 0x1000 as before.
It puts a jmp insn in at 0x210000 for backward compatibility with
bootloaders which don't look at the entry point of the loaded image.
This would break parameter passing for anyone who is currently using a
zImage and passing parameters by putting the param block at the beginning
of memory.
Is anyone actually doing that?
Index: arch/sh/boot/compressed/Makefile
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/boot/compressed/Makefile,v
retrieving revision 1.6
diff -u -r1.6 Makefile
--- arch/sh/boot/compressed/Makefile 2000/10/03 00:47:32 1.6
+++ arch/sh/boot/compressed/Makefile 2001/07/04 13:38:43
@@ -19,8 +19,9 @@
# ZIMAGE_OFFSET is the load offset of the compression loader
#
ZIMAGE_OFFSET = $(shell printf "0x%8x" $$[0x80000000+0x$(CONFIG_MEMORY_START)+0x200000+0x10000])
+ZIMAGE_ENTRY = $(shell printf "0x%8x" $$[$(ZIMAGE_OFFSET)+0x1000])
-ZLINKFLAGS = -Ttext $(ZIMAGE_OFFSET) $(ZLDFLAGS)
+ZLINKFLAGS = -Ttext $(ZIMAGE_OFFSET) $(ZLDFLAGS) -e $(ZIMAGE_ENTRY)
all: vmlinux
Index: arch/sh/boot/compressed/head.S
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/boot/compressed/head.S,v
retrieving revision 1.5
diff -u -r1.5 head.S
--- arch/sh/boot/compressed/head.S 2000/12/24 23:52:56 1.5
+++ arch/sh/boot/compressed/head.S 2001/07/04 13:38:44
@@ -8,7 +8,19 @@
#include <linux/linkage.h>
+ .global params
+
+params:
+ mov.l startup_addr, r0
+ jmp @r0
+
+startup_addr:
+ .long startup
+
+.org 0x1000
+
.global startup
+
startup:
/* Load initial status register */
mov.l init_sr, r1
Index: arch/sh/boot/compressed/misc.c
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/boot/compressed/misc.c,v
retrieving revision 1.5
diff -u -r1.5 misc.c
--- arch/sh/boot/compressed/misc.c 2000/07/20 15:55:00 1.5
+++ arch/sh/boot/compressed/misc.c 2001/07/04 13:38:44
@@ -96,6 +96,7 @@
extern int _end;
static unsigned long free_mem_ptr;
static unsigned long free_mem_end_ptr;
+extern int params;
#define HEAP_SIZE 0x10000
@@ -224,6 +225,18 @@
long user_stack [STACK_SIZE];
long* stack_start = &user_stack[STACK_SIZE];
+void copy_param_block(void)
+{
+ int i;
+
+ unsigned long *src = (unsigned long *)¶ms;
+ unsigned long *dst = (unsigned long *)&_text + 0x20000000;
+
+ for(i=0; i<0x1000/4; i++) {
+ dst[i]=src[i];
+ }
+}
+
void decompress_kernel(void)
{
output_data = 0;
@@ -231,6 +244,7 @@
free_mem_ptr = (unsigned long)&_end;
free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
+ copy_param_block();
makecrc();
puts("Uncompressing Linux... ");
gunzip();
--
dwmw2
|
|
From: Dustin M. <du...@se...> - 2001-09-03 20:23:52
|
I'm using Redboot with Yaegashi Takeshi's kernel boot loader support added.
This copies a run time configurable parameter block to a specified address.
I guess I could move this copy location to 0x210000 instead of 0x0. It
would just get copied twice (to 0x210000 and then to 0x0), but that may not
be a big deal. I guess I don't object to moving the parameter block
location, as long as there is still a way to copy parameter blocks at run
time.
Dustin.
> -----Original Message-----
> From: lin...@li...
> [mailto:lin...@li...]On Behalf Of David
> Woodhouse
> Sent: Monday, September 03, 2001 9:26 AM
> To: linuxsh-dev
> Subject: [linuxsh-dev] Parameter block with zImage.
>
>
> When we load a zImage, we load it to 0x210000 and it decompresses the real
> kernel image to 0x1000.
>
> The parameter block is in the first page of memory, and the zImage
> decompression code doesn't touch it. The bootloader is expected
> to load the
> zImage to 0x210000 and the parameters to 0x0.
>
> Does anyone actually pass parameters to the kernel this way? I'd like to
> change the address at which the zImage expects the parameter block to be
> loaded - to load it to the beginning of the zImage just as we would
> normally load it at the beginning of a vmlinux.
>
> The attached patch does this - moves the entry point of the zImage to
> 0x211000 and makes it copy the parameter block from 0x210000 to 0 after
> decompressing the kernel image to 0x1000 as before.
>
> It puts a jmp insn in at 0x210000 for backward compatibility with
> bootloaders which don't look at the entry point of the loaded image.
>
> This would break parameter passing for anyone who is currently using a
> zImage and passing parameters by putting the param block at the beginning
> of memory.
>
> Is anyone actually doing that?
>
> Index: arch/sh/boot/compressed/Makefile
> ===================================================================
> RCS file: /cvsroot/linuxsh/kernel/arch/sh/boot/compressed/Makefile,v
> retrieving revision 1.6
> diff -u -r1.6 Makefile
> --- arch/sh/boot/compressed/Makefile 2000/10/03 00:47:32 1.6
> +++ arch/sh/boot/compressed/Makefile 2001/07/04 13:38:43
> @@ -19,8 +19,9 @@
> # ZIMAGE_OFFSET is the load offset of the compression loader
> #
> ZIMAGE_OFFSET = $(shell printf "0x%8x"
> $$[0x80000000+0x$(CONFIG_MEMORY_START)+0x200000+0x10000])
> +ZIMAGE_ENTRY = $(shell printf "0x%8x" $$[$(ZIMAGE_OFFSET)+0x1000])
>
> -ZLINKFLAGS = -Ttext $(ZIMAGE_OFFSET) $(ZLDFLAGS)
> +ZLINKFLAGS = -Ttext $(ZIMAGE_OFFSET) $(ZLDFLAGS) -e $(ZIMAGE_ENTRY)
>
> all: vmlinux
>
> Index: arch/sh/boot/compressed/head.S
> ===================================================================
> RCS file: /cvsroot/linuxsh/kernel/arch/sh/boot/compressed/head.S,v
> retrieving revision 1.5
> diff -u -r1.5 head.S
> --- arch/sh/boot/compressed/head.S 2000/12/24 23:52:56 1.5
> +++ arch/sh/boot/compressed/head.S 2001/07/04 13:38:44
> @@ -8,7 +8,19 @@
>
> #include <linux/linkage.h>
>
> + .global params
> +
> +params:
> + mov.l startup_addr, r0
> + jmp @r0
> +
> +startup_addr:
> + .long startup
> +
> +.org 0x1000
> +
> .global startup
> +
> startup:
> /* Load initial status register */
> mov.l init_sr, r1
> Index: arch/sh/boot/compressed/misc.c
> ===================================================================
> RCS file: /cvsroot/linuxsh/kernel/arch/sh/boot/compressed/misc.c,v
> retrieving revision 1.5
> diff -u -r1.5 misc.c
> --- arch/sh/boot/compressed/misc.c 2000/07/20 15:55:00 1.5
> +++ arch/sh/boot/compressed/misc.c 2001/07/04 13:38:44
> @@ -96,6 +96,7 @@
> extern int _end;
> static unsigned long free_mem_ptr;
> static unsigned long free_mem_end_ptr;
> +extern int params;
>
> #define HEAP_SIZE 0x10000
>
> @@ -224,6 +225,18 @@
> long user_stack [STACK_SIZE];
> long* stack_start = &user_stack[STACK_SIZE];
>
> +void copy_param_block(void)
> +{
> + int i;
> +
> + unsigned long *src = (unsigned long *)¶ms;
> + unsigned long *dst = (unsigned long *)&_text + 0x20000000;
> +
> + for(i=0; i<0x1000/4; i++) {
> + dst[i]=src[i];
> + }
> +}
> +
> void decompress_kernel(void)
> {
> output_data = 0;
> @@ -231,6 +244,7 @@
> free_mem_ptr = (unsigned long)&_end;
> free_mem_end_ptr = free_mem_ptr + HEAP_SIZE;
>
> + copy_param_block();
> makecrc();
> puts("Uncompressing Linux... ");
> gunzip();
>
> --
> dwmw2
>
>
>
> _______________________________________________
> linuxsh-dev mailing list
> lin...@li...
> https://lists.sourceforge.net/lists/listinfo/linuxsh-dev
>
|
|
From: David W. <dw...@in...> - 2001-09-03 21:23:22
|
du...@se... said: > I'm using Redboot with Yaegashi Takeshi's kernel boot loader support > added. This copies a run time configurable parameter block to a > specified address. I guess I could move this copy location to 0x210000 > instead of 0x0. It would just get copied twice (to 0x210000 and then > to 0x0), but that may not be a big deal. I guess I don't object to > moving the parameter block location, as long as there is still a way > to copy parameter blocks at run time. Hmmm. It occurs to me that I could probably have done the same instead of hacking the zImage code. I was assuming that RedBoot required the first page of memory, but it actually sets up the parameter block after disabling interrupts and flushing caches, etc - just before jumping into the kernel. So I should be able to just specify '-b 0' to the exec command. -- dwmw2 |
|
From: NIIBE Y. <gn...@m1...> - 2001-09-03 23:31:04
|
David Woodhouse wrote: > Is anyone actually doing that? For the record. Our version of LILO does. So does our version of etherboot. But they could be changed, as it is not a big deal. -- |
|
From: David W. <dw...@in...> - 2001-09-03 23:58:00
|
gn...@m1... said: > For the record. Our version of LILO does. So does our version of > etherboot. But they could be changed, as it is not a big deal. Well, there's no particular reason to change it, I suppose - it just seemed neater at the time to change the kernel to load the parameter block near the zImage than to change the bootloader. I'll fix up my RedBoot defaults to match the kernel. -- dwmw2 |
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