Menu
▾
▴
RE: [linuxsh-dev] Parameter block with zImage.
|
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
>
|
