forked from Minki/linux
ee9d21b3b3
When building with clang crt0's _zimage_start is not marked weak, which breaks the build when linking the kernel image: $ objdump -t arch/powerpc/boot/crt0.o |grep _zimage_start$ 0000000000000058 g .text 0000000000000000 _zimage_start ld: arch/powerpc/boot/wrapper.a(crt0.o): in function '_zimage_start': (.text+0x58): multiple definition of '_zimage_start'; arch/powerpc/boot/pseries-head.o:(.text+0x0): first defined here Clang requires the .weak directive to appear after the symbol is declared. The binutils manual says: This directive sets the weak attribute on the comma separated list of symbol names. If the symbols do not already exist, they will be created. So it appears this is different with clang. The only reference I could see for this was an OpenBSD mailing list post[1]. Changing it to be after the declaration fixes building with Clang, and still works with GCC. $ objdump -t arch/powerpc/boot/crt0.o |grep _zimage_start$ 0000000000000058 w .text 0000000000000000 _zimage_start Reported to clang as https://bugs.llvm.org/show_bug.cgi?id=38921 [1] https://groups.google.com/forum/#!topic/fa.openbsd.tech/PAgKKen2YCY Signed-off-by: Joel Stanley <joel@jms.id.au> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
303 lines
7.1 KiB
ArmAsm
303 lines
7.1 KiB
ArmAsm
/*
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* Copyright (C) Paul Mackerras 1997.
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*
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* Adapted for 64 bit LE PowerPC by Andrew Tauferner
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include "ppc_asm.h"
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RELA = 7
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RELACOUNT = 0x6ffffff9
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.text
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/* A procedure descriptor used when booting this as a COFF file.
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* When making COFF, this comes first in the link and we're
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* linked at 0x500000.
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*/
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.globl _zimage_start_opd
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_zimage_start_opd:
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.long 0x500000, 0, 0, 0
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#ifdef __powerpc64__
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.balign 8
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p_start: .8byte _start
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p_etext: .8byte _etext
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p_bss_start: .8byte __bss_start
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p_end: .8byte _end
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p_toc: .8byte __toc_start + 0x8000 - p_base
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p_dyn: .8byte __dynamic_start - p_base
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p_rela: .8byte __rela_dyn_start - p_base
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p_prom: .8byte 0
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.weak _platform_stack_top
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p_pstack: .8byte _platform_stack_top
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#else
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p_start: .long _start
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p_etext: .long _etext
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p_bss_start: .long __bss_start
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p_end: .long _end
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.weak _platform_stack_top
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p_pstack: .long _platform_stack_top
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#endif
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.globl _zimage_start
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/* Clang appears to require the .weak directive to be after the symbol
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* is defined. See https://bugs.llvm.org/show_bug.cgi?id=38921 */
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.weak _zimage_start
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_zimage_start:
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.globl _zimage_start_lib
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_zimage_start_lib:
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/* Work out the offset between the address we were linked at
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and the address where we're running. */
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bl .+4
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p_base: mflr r10 /* r10 now points to runtime addr of p_base */
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#ifndef __powerpc64__
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/* grab the link address of the dynamic section in r11 */
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addis r11,r10,(_GLOBAL_OFFSET_TABLE_-p_base)@ha
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lwz r11,(_GLOBAL_OFFSET_TABLE_-p_base)@l(r11)
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cmpwi r11,0
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beq 3f /* if not linked -pie */
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/* get the runtime address of the dynamic section in r12 */
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.weak __dynamic_start
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addis r12,r10,(__dynamic_start-p_base)@ha
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addi r12,r12,(__dynamic_start-p_base)@l
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subf r11,r11,r12 /* runtime - linktime offset */
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/* The dynamic section contains a series of tagged entries.
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* We need the RELA and RELACOUNT entries. */
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li r9,0
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li r0,0
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9: lwz r8,0(r12) /* get tag */
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cmpwi r8,0
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beq 10f /* end of list */
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cmpwi r8,RELA
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bne 11f
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lwz r9,4(r12) /* get RELA pointer in r9 */
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b 12f
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11: addis r8,r8,(-RELACOUNT)@ha
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cmpwi r8,RELACOUNT@l
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bne 12f
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lwz r0,4(r12) /* get RELACOUNT value in r0 */
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12: addi r12,r12,8
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b 9b
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/* The relocation section contains a list of relocations.
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* We now do the R_PPC_RELATIVE ones, which point to words
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* which need to be initialized with addend + offset.
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* The R_PPC_RELATIVE ones come first and there are RELACOUNT
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* of them. */
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10: /* skip relocation if we don't have both */
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cmpwi r0,0
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beq 3f
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cmpwi r9,0
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beq 3f
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add r9,r9,r11 /* Relocate RELA pointer */
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mtctr r0
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2: lbz r0,4+3(r9) /* ELF32_R_INFO(reloc->r_info) */
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cmpwi r0,22 /* R_PPC_RELATIVE */
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bne 3f
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lwz r12,0(r9) /* reloc->r_offset */
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lwz r0,8(r9) /* reloc->r_addend */
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add r0,r0,r11
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stwx r0,r11,r12
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addi r9,r9,12
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bdnz 2b
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/* Do a cache flush for our text, in case the loader didn't */
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3: lwz r9,p_start-p_base(r10) /* note: these are relocated now */
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lwz r8,p_etext-p_base(r10)
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4: dcbf r0,r9
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icbi r0,r9
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addi r9,r9,0x20
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cmplw cr0,r9,r8
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blt 4b
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sync
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isync
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/* Clear the BSS */
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lwz r9,p_bss_start-p_base(r10)
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lwz r8,p_end-p_base(r10)
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li r0,0
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5: stw r0,0(r9)
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addi r9,r9,4
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cmplw cr0,r9,r8
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blt 5b
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/* Possibly set up a custom stack */
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lwz r8,p_pstack-p_base(r10)
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cmpwi r8,0
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beq 6f
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lwz r1,0(r8)
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li r0,0
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stwu r0,-16(r1) /* establish a stack frame */
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6:
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#else /* __powerpc64__ */
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/* Save the prom pointer at p_prom. */
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std r5,(p_prom-p_base)(r10)
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/* Set r2 to the TOC. */
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ld r2,(p_toc-p_base)(r10)
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add r2,r2,r10
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/* Grab the link address of the dynamic section in r11. */
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ld r11,-32768(r2)
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cmpwi r11,0
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beq 3f /* if not linked -pie then no dynamic section */
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ld r11,(p_dyn-p_base)(r10)
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add r11,r11,r10
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ld r9,(p_rela-p_base)(r10)
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add r9,r9,r10
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li r13,0
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li r8,0
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9: ld r12,0(r11) /* get tag */
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cmpdi r12,0
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beq 12f /* end of list */
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cmpdi r12,RELA
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bne 10f
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ld r13,8(r11) /* get RELA pointer in r13 */
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b 11f
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10: addis r12,r12,(-RELACOUNT)@ha
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cmpdi r12,RELACOUNT@l
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bne 11f
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ld r8,8(r11) /* get RELACOUNT value in r8 */
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11: addi r11,r11,16
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b 9b
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12:
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cmpdi r13,0 /* check we have both RELA and RELACOUNT */
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cmpdi cr1,r8,0
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beq 3f
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beq cr1,3f
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/* Calcuate the runtime offset. */
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subf r13,r13,r9
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/* Run through the list of relocations and process the
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* R_PPC64_RELATIVE ones. */
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mtctr r8
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13: ld r0,8(r9) /* ELF64_R_TYPE(reloc->r_info) */
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cmpdi r0,22 /* R_PPC64_RELATIVE */
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bne 3f
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ld r12,0(r9) /* reloc->r_offset */
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ld r0,16(r9) /* reloc->r_addend */
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add r0,r0,r13
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stdx r0,r13,r12
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addi r9,r9,24
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bdnz 13b
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/* Do a cache flush for our text, in case the loader didn't */
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3: ld r9,p_start-p_base(r10) /* note: these are relocated now */
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ld r8,p_etext-p_base(r10)
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4: dcbf r0,r9
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icbi r0,r9
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addi r9,r9,0x20
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cmpld cr0,r9,r8
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blt 4b
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sync
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isync
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/* Clear the BSS */
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ld r9,p_bss_start-p_base(r10)
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ld r8,p_end-p_base(r10)
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li r0,0
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5: std r0,0(r9)
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addi r9,r9,8
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cmpld cr0,r9,r8
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blt 5b
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/* Possibly set up a custom stack */
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ld r8,p_pstack-p_base(r10)
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cmpdi r8,0
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beq 6f
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ld r1,0(r8)
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li r0,0
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stdu r0,-112(r1) /* establish a stack frame */
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6:
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#endif /* __powerpc64__ */
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/* Call platform_init() */
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bl platform_init
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/* Call start */
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b start
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#ifdef __powerpc64__
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#define PROM_FRAME_SIZE 512
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#define SAVE_GPR(n, base) std n,8*(n)(base)
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#define REST_GPR(n, base) ld n,8*(n)(base)
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#define SAVE_2GPRS(n, base) SAVE_GPR(n, base); SAVE_GPR(n+1, base)
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#define SAVE_4GPRS(n, base) SAVE_2GPRS(n, base); SAVE_2GPRS(n+2, base)
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#define SAVE_8GPRS(n, base) SAVE_4GPRS(n, base); SAVE_4GPRS(n+4, base)
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#define SAVE_10GPRS(n, base) SAVE_8GPRS(n, base); SAVE_2GPRS(n+8, base)
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#define REST_2GPRS(n, base) REST_GPR(n, base); REST_GPR(n+1, base)
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#define REST_4GPRS(n, base) REST_2GPRS(n, base); REST_2GPRS(n+2, base)
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#define REST_8GPRS(n, base) REST_4GPRS(n, base); REST_4GPRS(n+4, base)
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#define REST_10GPRS(n, base) REST_8GPRS(n, base); REST_2GPRS(n+8, base)
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/* prom handles the jump into and return from firmware. The prom args pointer
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is loaded in r3. */
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.globl prom
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prom:
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mflr r0
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std r0,16(r1)
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stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */
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SAVE_GPR(2, r1)
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SAVE_GPR(13, r1)
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SAVE_8GPRS(14, r1)
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SAVE_10GPRS(22, r1)
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mfcr r10
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std r10,8*32(r1)
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mfmsr r10
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std r10,8*33(r1)
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/* remove MSR_LE from msr but keep MSR_SF */
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mfmsr r10
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rldicr r10,r10,0,62
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mtsrr1 r10
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/* Load FW address, set LR to label 1, and jump to FW */
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bl 0f
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0: mflr r10
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addi r11,r10,(1f-0b)
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mtlr r11
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ld r10,(p_prom-0b)(r10)
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mtsrr0 r10
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rfid
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1: /* Return from OF */
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FIXUP_ENDIAN
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/* Restore registers and return. */
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rldicl r1,r1,0,32
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/* Restore the MSR (back to 64 bits) */
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ld r10,8*(33)(r1)
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mtmsr r10
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isync
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/* Restore other registers */
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REST_GPR(2, r1)
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REST_GPR(13, r1)
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REST_8GPRS(14, r1)
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REST_10GPRS(22, r1)
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ld r10,8*32(r1)
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mtcr r10
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addi r1,r1,PROM_FRAME_SIZE
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ld r0,16(r1)
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mtlr r0
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blr
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#endif
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