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