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549e8152 PM |
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 | |
3b830c82 LD |
72 | 5: ld r0,8(9) /* ELF64_R_TYPE(reloc->r_info) */ |
73 | cmpdi r0,R_PPC64_RELATIVE | |
549e8152 PM |
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 | ||
a5b2cf5b | 84 | .balign 8 |
549e8152 PM |
85 | p_dyn: .llong __dynamic_start - 0b |
86 | p_rela: .llong __rela_dyn_start - 0b | |
87 | p_st: .llong _stext - 0b | |
88 |