1 /* SPDX-License-Identifier: GPL-2.0-or-later *
2 /*
3 * Code to process dynamic relocations for PPC
4 *
5 * Copyrights (C) IBM Corporation, 2011.
6 * Author: Suzuki Poulose <suzuki@in.ibm.c
7 *
8 * - Based on ppc64 code - reloc_64.S
9 */
10
11 #include <asm/ppc_asm.h>
12
13 /* Dynamic section table entry tags */
14 DT_RELA = 7 /* Tag for Elf
15 DT_RELASZ = 8 /* Size of the
16 DT_RELAENT = 9 /* Size of one
17
18 STN_UNDEF = 0 /* Undefined s
19 STB_LOCAL = 0 /* Local bindi
20
21 R_PPC_ADDR16_LO = 4 /* Lower half
22 R_PPC_ADDR16_HI = 5 /* Upper half
23 R_PPC_ADDR16_HA = 6 /* High Adjust
24 R_PPC_RELATIVE = 22
25
26 /*
27 * r3 = desired final address
28 */
29
30 _GLOBAL(relocate)
31
32 mflr r0 /* Save our LR
33 bcl 20,31,$+4 /* Find our cu
34 0: mflr r12 /* Make it acc
35 mtlr r0
36
37 lwz r11, (p_dyn - 0b)(r12)
38 add r11, r11, r12 /* runtime add
39 lwz r9, (p_rela - 0b)(r12)
40 add r9, r9, r12 /* runtime add
41 lwz r10, (p_st - 0b)(r12)
42 add r10, r10, r12 /* runtime add
43 lwz r13, (p_sym - 0b)(r12)
44 add r13, r13, r12 /* runtime add
45
46 /*
47 * Scan the dynamic section for RELA,
48 */
49 li r6, 0
50 li r7, 0
51 li r8, 0
52 1: lwz r5, 0(r11) /* ELF_Dyn.d_t
53 cmpwi r5, 0 /* End of ELF_
54 beq eodyn
55 cmpwi r5, DT_RELA
56 bne relasz
57 lwz r7, 4(r11) /* r7 = rela.l
58 b skip
59 relasz:
60 cmpwi r5, DT_RELASZ
61 bne relaent
62 lwz r8, 4(r11) /* r8 = Total
63 b skip
64 relaent:
65 cmpwi r5, DT_RELAENT
66 bne skip
67 lwz r6, 4(r11) /* r6 = Size o
68 skip:
69 addi r11, r11, 8
70 b 1b
71 eodyn: /* End of Dyn
72
73 /* Check if we have found all the entr
74 cmpwi r7, 0
75 beq done
76 cmpwi r8, 0
77 beq done
78 cmpwi r6, 0
79 beq done
80
81
82 /*
83 * Work out the current offset from th
84 * section.
85 * cur_offset[r7] = rela.run[r9] - re
86 * _stext.link[r12] = _stext.run[r10]
87 * final_offset[r3] = _stext.final[r3
88 */
89 subf r7, r7, r9 /* cur_offset
90 subf r12, r7, r10
91 subf r3, r12, r3 /* final_offse
92
93 subf r8, r6, r8 /* relaz -= re
94 /*
95 * Scan through the .rela table and pr
96 * r9 - points to the current .rela
97 * r13 - points to the symbol table
98 */
99
100 /*
101 * Check if we have a relocation based
102 * r5 will hold the value of the symbo
103 */
104 applyrela:
105 lwz r4, 4(r9) /* r4
106 srwi r5, r4, 8 /* ELF
107 cmpwi r5, STN_UNDEF /* sym == STN_
108 beq get_type /* value = 0 *
109 /* Find the value of the symbol at ind
110 slwi r5, r5, 4 /* r5
111 add r12, r13, r5 /* r12 = &__dy
112
113 /*
114 * GNU ld has a bug, where dynamic rel
115 * STB_LOCAL symbols, the value should
116 * to be zero. - Alan Modra
117 */
118 /* XXX: Do we need to check if we are
119 lbz r5, 12(r12) /* r5 = dyn_sy
120 extrwi r5, r5, 4, 24 /* r5 = ELF32_
121 cmpwi r5, STB_LOCAL /* st_value =
122 beq get_type /* We have r5
123 lwz r5, 4(r12) /* r5 = __dyn_
124
125 get_type:
126 /* Load the relocation type to r4 */
127 extrwi r4, r4, 8, 24 /* r4 = ELF32_
128
129 /* R_PPC_RELATIVE */
130 cmpwi r4, R_PPC_RELATIVE
131 bne hi16
132 lwz r4, 0(r9) /* r_offset */
133 lwz r0, 8(r9) /* r_addend */
134 add r0, r0, r3 /* final adden
135 stwx r0, r4, r7 /* memory[r4+r
136 b nxtrela /* continue */
137
138 /* R_PPC_ADDR16_HI */
139 hi16:
140 cmpwi r4, R_PPC_ADDR16_HI
141 bne ha16
142 lwz r4, 0(r9) /* r_offset */
143 lwz r0, 8(r9) /* r_addend */
144 add r0, r0, r3
145 add r0, r0, r5 /* r0 = (S+A+O
146 extrwi r0, r0, 16, 0 /* r0 = (r0 >>
147 b store_half
148
149 /* R_PPC_ADDR16_HA */
150 ha16:
151 cmpwi r4, R_PPC_ADDR16_HA
152 bne lo16
153 lwz r4, 0(r9) /* r_offset */
154 lwz r0, 8(r9) /* r_addend */
155 add r0, r0, r3
156 add r0, r0, r5 /* r0 = (S+A+O
157 extrwi r5, r0, 1, 16 /* Extract bit
158 extrwi r0, r0, 16, 0 /* r0 = (r0 >>
159 add r0, r0, r5 /* Add it to r
160 b store_half
161
162 /* R_PPC_ADDR16_LO */
163 lo16:
164 cmpwi r4, R_PPC_ADDR16_LO
165 bne unknown_type
166 lwz r4, 0(r9) /* r_offset */
167 lwz r0, 8(r9) /* r_addend */
168 add r0, r0, r3
169 add r0, r0, r5 /* r0 = (S+A+O
170 extrwi r0, r0, 16, 16 /* r0 &= 0xfff
171 /* Fall through to */
172
173 /* Store half word */
174 store_half:
175 sthx r0, r4, r7 /* memory[r4+r
176
177 nxtrela:
178 /*
179 * We have to flush the modified instr
180 * main storage from the d-cache. And
181 * cached instructions in i-cache whic
182 *
183 * We delay the sync / isync operation
184 * we won't be executing the modified
185 * we return from here.
186 */
187 dcbst r4,r7
188 sync /* Ensure the
189 icbi r4,r7
190 unknown_type:
191 cmpwi r8, 0 /* relasz = 0
192 ble done
193 add r9, r9, r6 /* move to nex
194 subf r8, r6, r8 /* relasz -= r
195 b applyrela
196
197 done:
198 sync /* Wait for th
199 isync /* Discard pre
200 blr
201
202 p_dyn: .long __dynamic_start - 0b
203 p_rela: .long __rela_dyn_start - 0b
204 p_sym: .long __dynamic_symtab - 0b
205 p_st: .long _stext - 0b
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