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Diffstat (limited to 'arch/ppc/boot/common/crt0.S')
| -rw-r--r-- | arch/ppc/boot/common/crt0.S | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/arch/ppc/boot/common/crt0.S b/arch/ppc/boot/common/crt0.S new file mode 100644 index 00000000000..4d31b824bbd --- /dev/null +++ b/arch/ppc/boot/common/crt0.S @@ -0,0 +1,81 @@ +/* Copyright (c) 1997 Paul Mackerras <paulus@cs.anu.edu.au> + * Initial Power Macintosh COFF version. + * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu> + * Modifications for IBM PowerPC 400-class processor evaluation + * boards. + * + * Module name: crt0.S + * + * Description: + * Boot loader execution entry point. Clears out .bss section as per + * ANSI C requirements. Invalidates and flushes the caches over the + * range covered by the boot loader's .text section. Sets up a stack + * below the .text section entry point. + * + * 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. + */ + +#include <linux/config.h> +#include <asm/ppc_asm.h> + + .text + + .globl _start +_start: +#ifdef XCOFF + .long __start,0,0 + + .globl __start +__start: +#endif + + ## Flush and invalidate the caches for the range in memory covering + ## the .text section of the boot loader + + lis r9,_start@h # r9 = &_start + lis r8,_etext@ha # + addi r8,r8,_etext@l # r8 = &_etext +3: dcbf r0,r9 # Flush the data cache + icbi r0,r9 # Invalidate the instruction cache + addi r9,r9,0x10 # Increment by one cache line + cmplw cr0,r9,r8 # Are we at the end yet? + blt 3b # No, keep flushing and invalidating + sync # sync ; isync after flushing the icache + isync + + ## Clear out the BSS as per ANSI C requirements + + lis r7,_end@ha + addi r7,r7,_end@l # r7 = &_end + lis r8,__bss_start@ha # + addi r8,r8,__bss_start@l # r8 = &_bss_start + + ## Determine how large an area, in number of words, to clear + + subf r7,r8,r7 # r7 = &_end - &_bss_start + 1 + addi r7,r7,3 # r7 += 3 + srwi. r7,r7,2 # r7 = size in words. + beq 2f # If the size is zero, do not bother + addi r8,r8,-4 # r8 -= 4 + mtctr r7 # SPRN_CTR = number of words to clear + li r0,0 # r0 = 0 +1: stwu r0,4(r8) # Clear out a word + bdnz 1b # If we are not done yet, keep clearing +2: + +#ifdef CONFIG_40x + ## Set up the stack + + lis r9,_start@h # r9 = &_start (text section entry) + ori r9,r9,_start@l + subi r1,r9,64 # Start the stack 64 bytes below _start + clrrwi r1,r1,4 # Make sure it is aligned on 16 bytes. + li r0,0 + stwu r0,-16(r1) + mtlr r9 +#endif + + b start # All done, start the real work. |