| Paul Mackerras | 549e815 | 2008-08-30 11:43:47 +1000 | [diff] [blame] | 1 | /* |
| 2 | * Code to process dynamic relocations in the kernel. |
| 3 | * |
| 4 | * Copyright 2008 Paul Mackerras, IBM Corp. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the License, or (at your option) any later version. |
| 10 | */ |
| 11 | |
| 12 | #include <asm/ppc_asm.h> |
| 13 | |
| 14 | RELA = 7 |
| 15 | RELACOUNT = 0x6ffffff9 |
| 16 | R_PPC64_RELATIVE = 22 |
| 17 | |
| 18 | /* |
| 19 | * r3 = desired final address of kernel |
| 20 | */ |
| 21 | _GLOBAL(relocate) |
| 22 | mflr r0 |
| 23 | bcl 20,31,$+4 |
| 24 | 0: mflr r12 /* r12 has runtime addr of label 0 */ |
| 25 | mtlr r0 |
| 26 | ld r11,(p_dyn - 0b)(r12) |
| 27 | add r11,r11,r12 /* r11 has runtime addr of .dynamic section */ |
| 28 | ld r9,(p_rela - 0b)(r12) |
| 29 | add r9,r9,r12 /* r9 has runtime addr of .rela.dyn section */ |
| 30 | ld r10,(p_st - 0b)(r12) |
| 31 | add r10,r10,r12 /* r10 has runtime addr of _stext */ |
| 32 | |
| 33 | /* |
| 34 | * Scan the dynamic section for the RELA and RELACOUNT entries. |
| 35 | */ |
| 36 | li r7,0 |
| 37 | li r8,0 |
| 38 | 1: ld r6,0(r11) /* get tag */ |
| 39 | cmpdi r6,0 |
| 40 | beq 4f /* end of list */ |
| 41 | cmpdi r6,RELA |
| 42 | bne 2f |
| 43 | ld r7,8(r11) /* get RELA pointer in r7 */ |
| 44 | b 3f |
| 45 | 2: addis r6,r6,(-RELACOUNT)@ha |
| 46 | cmpdi r6,RELACOUNT@l |
| 47 | bne 3f |
| 48 | ld r8,8(r11) /* get RELACOUNT value in r8 */ |
| 49 | 3: addi r11,r11,16 |
| 50 | b 1b |
| 51 | 4: cmpdi r7,0 /* check we have both RELA and RELACOUNT */ |
| 52 | cmpdi cr1,r8,0 |
| 53 | beq 6f |
| 54 | beq cr1,6f |
| 55 | |
| 56 | /* |
| 57 | * Work out linktime address of _stext and hence the |
| 58 | * relocation offset to be applied. |
| 59 | * cur_offset [r7] = rela.run [r9] - rela.link [r7] |
| 60 | * _stext.link [r10] = _stext.run [r10] - cur_offset [r7] |
| 61 | * final_offset [r3] = _stext.final [r3] - _stext.link [r10] |
| 62 | */ |
| 63 | subf r7,r7,r9 /* cur_offset */ |
| 64 | subf r10,r7,r10 |
| 65 | subf r3,r10,r3 /* final_offset */ |
| 66 | |
| 67 | /* |
| 68 | * Run through the list of relocations and process the |
| 69 | * R_PPC64_RELATIVE ones. |
| 70 | */ |
| 71 | mtctr r8 |
| 72 | 5: lwz r0,12(9) /* ELF64_R_TYPE(reloc->r_info) */ |
| 73 | cmpwi r0,R_PPC64_RELATIVE |
| 74 | bne 6f |
| 75 | ld r6,0(r9) /* reloc->r_offset */ |
| 76 | ld r0,16(r9) /* reloc->r_addend */ |
| 77 | add r0,r0,r3 |
| 78 | stdx r0,r7,r6 |
| 79 | addi r9,r9,24 |
| 80 | bdnz 5b |
| 81 | |
| 82 | 6: blr |
| 83 | |
| 84 | p_dyn: .llong __dynamic_start - 0b |
| 85 | p_rela: .llong __rela_dyn_start - 0b |
| 86 | p_st: .llong _stext - 0b |
| 87 | |