88 lines
2 KiB
ArmAsm
88 lines
2 KiB
ArmAsm
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/*
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* Code to process dynamic relocations in the kernel.
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*
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* Copyright 2008 Paul Mackerras, IBM Corp.
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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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#include <asm/ppc_asm.h>
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RELA = 7
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RELACOUNT = 0x6ffffff9
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R_PPC64_RELATIVE = 22
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/*
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* r3 = desired final address of kernel
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*/
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_GLOBAL(relocate)
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mflr r0
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bcl 20,31,$+4
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0: mflr r12 /* r12 has runtime addr of label 0 */
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mtlr r0
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ld r11,(p_dyn - 0b)(r12)
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add r11,r11,r12 /* r11 has runtime addr of .dynamic section */
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ld r9,(p_rela - 0b)(r12)
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add r9,r9,r12 /* r9 has runtime addr of .rela.dyn section */
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ld r10,(p_st - 0b)(r12)
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add r10,r10,r12 /* r10 has runtime addr of _stext */
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/*
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* Scan the dynamic section for the RELA and RELACOUNT entries.
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*/
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li r7,0
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li r8,0
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1: ld r6,0(r11) /* get tag */
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cmpdi r6,0
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beq 4f /* end of list */
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cmpdi r6,RELA
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bne 2f
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ld r7,8(r11) /* get RELA pointer in r7 */
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b 3f
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2: addis r6,r6,(-RELACOUNT)@ha
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cmpdi r6,RELACOUNT@l
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bne 3f
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ld r8,8(r11) /* get RELACOUNT value in r8 */
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3: addi r11,r11,16
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b 1b
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4: cmpdi r7,0 /* check we have both RELA and RELACOUNT */
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cmpdi cr1,r8,0
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beq 6f
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beq cr1,6f
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/*
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* Work out linktime address of _stext and hence the
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* relocation offset to be applied.
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* cur_offset [r7] = rela.run [r9] - rela.link [r7]
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* _stext.link [r10] = _stext.run [r10] - cur_offset [r7]
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* final_offset [r3] = _stext.final [r3] - _stext.link [r10]
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*/
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subf r7,r7,r9 /* cur_offset */
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subf r10,r7,r10
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subf r3,r10,r3 /* final_offset */
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/*
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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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*/
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mtctr r8
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5: lwz r0,12(9) /* ELF64_R_TYPE(reloc->r_info) */
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cmpwi r0,R_PPC64_RELATIVE
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bne 6f
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ld r6,0(r9) /* reloc->r_offset */
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ld r0,16(r9) /* reloc->r_addend */
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add r0,r0,r3
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stdx r0,r7,r6
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addi r9,r9,24
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bdnz 5b
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6: blr
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p_dyn: .llong __dynamic_start - 0b
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p_rela: .llong __rela_dyn_start - 0b
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p_st: .llong _stext - 0b
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