| /* |
| * 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 */ |
| _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 |
