kernel-ark/arch/powerpc/boot/crt0.S
Paul Mackerras f40e524eae [POWERPC] Fix building of COFF zImages
The COFF zImage (for booting oldworld powermacs) wasn't being built
correctly because the procedure descriptor in crt0.S for the zImage
entry point wasn't declared as .globl, and therefore wasn't getting
pulled in from wrapper.a by the linker.  This adds the necessary
.globl statement.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-07 22:21:31 +10:00

97 lines
1.9 KiB
ArmAsm

/*
* Copyright (C) Paul Mackerras 1997.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* NOTE: this code runs in 32 bit mode and is packaged as ELF32.
*/
#include "ppc_asm.h"
.text
/* a procedure descriptor used when booting this as a COFF file */
.globl _zimage_start_opd
_zimage_start_opd:
.long _zimage_start, 0, 0, 0
.weak _zimage_start
.globl _zimage_start
_zimage_start:
.globl _zimage_start_lib
_zimage_start_lib:
/* Work out the offset between the address we were linked at
and the address where we're running. */
bl 1f
1: mflr r0
lis r9,1b@ha
addi r9,r9,1b@l
subf. r0,r9,r0
beq 3f /* if running at same address as linked */
/* The .got2 section contains a list of addresses, so add
the address offset onto each entry. */
lis r9,__got2_start@ha
addi r9,r9,__got2_start@l
lis r8,__got2_end@ha
addi r8,r8,__got2_end@l
subf. r8,r9,r8
beq 3f
srwi. r8,r8,2
mtctr r8
add r9,r0,r9
2: lwz r8,0(r9)
add r8,r8,r0
stw r8,0(r9)
addi r9,r9,4
bdnz 2b
/* Do a cache flush for our text, in case the loader didn't */
3: lis r9,_start@ha
addi r9,r9,_start@l
add r9,r0,r9
lis r8,_etext@ha
addi r8,r8,_etext@l
add r8,r0,r8
4: dcbf r0,r9
icbi r0,r9
addi r9,r9,0x20
cmplw cr0,r9,r8
blt 4b
sync
isync
/* Clear the BSS */
lis r9,__bss_start@ha
addi r9,r9,__bss_start@l
add r9,r0,r9
lis r8,_end@ha
addi r8,r8,_end@l
add r8,r0,r8
li r10,0
5: stw r10,0(r9)
addi r9,r9,4
cmplw cr0,r9,r8
blt 5b
/* Possibly set up a custom stack */
.weak _platform_stack_top
lis r8,_platform_stack_top@ha
addi r8,r8,_platform_stack_top@l
cmpwi r8,0
beq 6f
add r8,r0,r8
lwz r1,0(r8)
add r1,r0,r1
li r0,0
stwu r0,-16(r1) /* establish a stack frame */
6:
/* Call platform_init() */
bl platform_init
/* Call start */
b start