1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Code to process dynamic relocations in the kernel. 4 * 5 * Copyright 2008 Paul Mackerras, IBM Corp. 6 */ 7 8 #include <asm/ppc_asm.h> 9 10 RELA = 7 11 RELACOUNT = 0x6ffffff9 12 R_PPC64_RELATIVE = 22 13 14 /* 15 * r3 = desired final address of kernel 16 */ 17 _GLOBAL(relocate) 18 mflr r0 19 bcl 20,31,$+4 20 0: mflr r12 /* r12 has runtime addr of label 0 */ 21 mtlr r0 22 ld r11,(p_dyn - 0b)(r12) 23 add r11,r11,r12 /* r11 has runtime addr of .dynamic section */ 24 ld r9,(p_rela - 0b)(r12) 25 add r9,r9,r12 /* r9 has runtime addr of .rela.dyn section */ 26 ld r10,(p_st - 0b)(r12) 27 add r10,r10,r12 /* r10 has runtime addr of _stext */ 28 29 /* 30 * Scan the dynamic section for the RELA and RELACOUNT entries. 31 */ 32 li r7,0 33 li r8,0 34 1: ld r6,0(r11) /* get tag */ 35 cmpdi r6,0 36 beq 4f /* end of list */ 37 cmpdi r6,RELA 38 bne 2f 39 ld r7,8(r11) /* get RELA pointer in r7 */ 40 b 3f 41 2: addis r6,r6,(-RELACOUNT)@ha 42 cmpdi r6,RELACOUNT@l 43 bne 3f 44 ld r8,8(r11) /* get RELACOUNT value in r8 */ 45 3: addi r11,r11,16 46 b 1b 47 4: cmpdi r7,0 /* check we have both RELA and RELACOUNT */ 48 cmpdi cr1,r8,0 49 beq 6f 50 beq cr1,6f 51 52 /* 53 * Work out linktime address of _stext and hence the 54 * relocation offset to be applied. 55 * cur_offset [r7] = rela.run [r9] - rela.link [r7] 56 * _stext.link [r10] = _stext.run [r10] - cur_offset [r7] 57 * final_offset [r3] = _stext.final [r3] - _stext.link [r10] 58 */ 59 subf r7,r7,r9 /* cur_offset */ 60 subf r10,r7,r10 61 subf r3,r10,r3 /* final_offset */ 62 63 /* 64 * Run through the list of relocations and process the 65 * R_PPC64_RELATIVE ones. 66 */ 67 mtctr r8 68 5: ld r0,8(9) /* ELF64_R_TYPE(reloc->r_info) */ 69 cmpdi r0,R_PPC64_RELATIVE 70 bne 6f 71 ld r6,0(r9) /* reloc->r_offset */ 72 ld r0,16(r9) /* reloc->r_addend */ 73 add r0,r0,r3 74 stdx r0,r7,r6 75 addi r9,r9,24 76 bdnz 5b 77 78 6: blr 79 80 .balign 8 81 p_dyn: .8byte __dynamic_start - 0b 82 p_rela: .8byte __rela_dyn_start - 0b 83 p_st: .8byte _stext - 0b 84