1 /* SPDX-License-Identifier: GPL-2.0-or-later *
2 /*
3 * Copyright (C) Paul Mackerras 1997.
4 *
5 * Adapted for 64 bit LE PowerPC by Andrew Tau
6 */
7
8 #include "ppc_asm.h"
9
10 RELA = 7
11 RELASZ = 8
12 RELAENT = 9
13
14 .data
15 /* A procedure descriptor used when bo
16 * When making COFF, this comes first
17 * linked at 0x500000.
18 */
19 .globl _zimage_start_opd
20 _zimage_start_opd:
21 .long 0x500000, 0, 0, 0
22 .text
23 b _zimage_start
24
25 #ifdef __powerpc64__
26 .balign 8
27 p_start: .8byte _start
28 p_etext: .8byte _etext
29 p_bss_start: .8byte __bss_start
30 p_end: .8byte _end
31
32 p_toc: .8byte .TOC. - p_base
33 p_dyn: .8byte __dynamic_start - p_ba
34 p_rela: .8byte __rela_dyn_start - p_b
35 p_prom: .8byte 0
36 .weak _platform_stack_top
37 p_pstack: .8byte _platform_stack_top
38 #else
39 p_start: .long _start
40 p_etext: .long _etext
41 p_bss_start: .long __bss_start
42 p_end: .long _end
43
44 .weak _platform_stack_top
45 p_pstack: .long _platform_stack_top
46 #endif
47
48 .weak _zimage_start
49 _zimage_start:
50 .globl _zimage_start_lib
51 _zimage_start_lib:
52 /* Work out the offset between the add
53 and the address where we're running
54 bcl 20,31,.+4
55 p_base: mflr r10 /* r10 now poi
56 #ifndef __powerpc64__
57 /* grab the link address of the dynami
58 addis r11,r10,(_GLOBAL_OFFSET_TABLE_
59 lwz r11,(_GLOBAL_OFFSET_TABLE_-p_b
60 cmpwi r11,0
61 beq 3f /* if not link
62 /* get the runtime address of the dyna
63 .weak __dynamic_start
64 addis r12,r10,(__dynamic_start-p_bas
65 addi r12,r12,(__dynamic_start-p_bas
66 subf r11,r11,r12 /* runtime - l
67
68 /* The dynamic section contains a seri
69 * We need the RELA and RELACOUNT entr
70 li r9,0
71 li r0,0
72 9: lwz r8,0(r12) /* get tag */
73 cmpwi r8,0
74 beq 10f /* end of list
75 cmpwi r8,RELA
76 bne 11f
77 lwz r9,4(r12) /* get RELA po
78 b 12f
79 11: cmpwi r8,RELASZ
80 bne .Lcheck_for_relaent
81 lwz r0,4(r12) /* get RELASZ
82 b 12f
83 .Lcheck_for_relaent:
84 cmpwi r8,RELAENT
85 bne 12f
86 lwz r14,4(r12) /* get RELAENT
87 12: addi r12,r12,8
88 b 9b
89
90 /* The relocation section contains a l
91 * We now do the R_PPC_RELATIVE ones,
92 * which need to be initialized with a
93 10: /* skip relocation if we don't have bo
94 cmpwi r0,0
95 beq 3f
96 cmpwi r9,0
97 beq 3f
98 cmpwi r14,0
99 beq 3f
100
101 add r9,r9,r11 /* Relocate RE
102 divwu r0,r0,r14 /* RELASZ / RE
103 mtctr r0
104 2: lbz r0,4+3(r9) /* ELF32_R_INF
105 cmpwi r0,22 /* R_PPC_RELAT
106 bne .Lnext
107 lwz r12,0(r9) /* reloc->r_of
108 lwz r0,8(r9) /* reloc->r_ad
109 add r0,r0,r11
110 stwx r0,r11,r12
111 .Lnext: add r9,r9,r14
112 bdnz 2b
113
114 /* Do a cache flush for our text, in c
115 3: lwz r9,p_start-p_base(r10) /* not
116 lwz r8,p_etext-p_base(r10)
117 4: dcbf r0,r9
118 icbi r0,r9
119 addi r9,r9,0x20
120 cmplw cr0,r9,r8
121 blt 4b
122 sync
123 isync
124
125 /* Clear the BSS */
126 lwz r9,p_bss_start-p_base(r10)
127 lwz r8,p_end-p_base(r10)
128 li r0,0
129 5: stw r0,0(r9)
130 addi r9,r9,4
131 cmplw cr0,r9,r8
132 blt 5b
133
134 /* Possibly set up a custom stack */
135 lwz r8,p_pstack-p_base(r10)
136 cmpwi r8,0
137 beq 6f
138 lwz r1,0(r8)
139 li r0,0
140 stwu r0,-16(r1) /* establish a
141 6:
142 #else /* __powerpc64__ */
143 /* Save the prom pointer at p_prom. */
144 std r5,(p_prom-p_base)(r10)
145
146 /* Set r2 to the TOC. */
147 ld r2,(p_toc-p_base)(r10)
148 add r2,r2,r10
149
150 /* Grab the link address of the dynami
151 ld r11,-32768(r2)
152 cmpwi r11,0
153 beq 3f /* if not link
154
155 ld r11,(p_dyn-p_base)(r10)
156 add r11,r11,r10
157 ld r9,(p_rela-p_base)(r10)
158 add r9,r9,r10
159
160 li r13,0
161 li r8,0
162 9: ld r12,0(r11) /* get tag */
163 cmpdi r12,0
164 beq 12f /* end of lis
165 cmpdi r12,RELA
166 bne 10f
167 ld r13,8(r11) /* get RELA p
168 b 11f
169 10: cmpwi r12,RELASZ
170 bne .Lcheck_for_relaent
171 lwz r8,8(r11) /* get RELASZ
172 b 11f
173 .Lcheck_for_relaent:
174 cmpwi r12,RELAENT
175 bne 11f
176 lwz r14,8(r11) /* get RELAENT
177 11: addi r11,r11,16
178 b 9b
179 12:
180 cmpdi r13,0 /* check we h
181 cmpdi cr1,r8,0
182 beq 3f
183 beq cr1,3f
184 cmpdi r14,0
185 beq 3f
186
187 /* Calcuate the runtime offset. */
188 subf r13,r13,r9
189
190 /* Run through the list of relocations
191 * R_PPC64_RELATIVE ones. */
192 divdu r8,r8,r14 /* RELASZ / RE
193 mtctr r8
194 13: ld r0,8(r9) /* ELF64_R_TYP
195 cmpdi r0,22 /* R_PPC64_REL
196 bne .Lnext
197 ld r12,0(r9) /* reloc->r_o
198 ld r0,16(r9) /* reloc->r_ad
199 add r0,r0,r13
200 stdx r0,r13,r12
201 .Lnext: add r9,r9,r14
202 bdnz 13b
203
204 /* Do a cache flush for our text, in c
205 3: ld r9,p_start-p_base(r10) /* not
206 ld r8,p_etext-p_base(r10)
207 4: dcbf r0,r9
208 icbi r0,r9
209 addi r9,r9,0x20
210 cmpld cr0,r9,r8
211 blt 4b
212 sync
213 isync
214
215 /* Clear the BSS */
216 ld r9,p_bss_start-p_base(r10)
217 ld r8,p_end-p_base(r10)
218 li r0,0
219 5: std r0,0(r9)
220 addi r9,r9,8
221 cmpld cr0,r9,r8
222 blt 5b
223
224 /* Possibly set up a custom stack */
225 ld r8,p_pstack-p_base(r10)
226 cmpdi r8,0
227 beq 6f
228 ld r1,0(r8)
229 li r0,0
230 stdu r0,-112(r1) /* establish a
231 6:
232 #endif /* __powerpc64__ */
233 /* Call platform_init() */
234 bl platform_init
235
236 /* Call start */
237 b start
238
239 #ifdef __powerpc64__
240
241 #define PROM_FRAME_SIZE 512
242
243 .macro OP_REGS op, width, start, end, base, of
244 .Lreg=\start
245 .rept (\end - \start + 1)
246 \op .Lreg,\offset+\width*.Lreg(\ba
247 .Lreg=.Lreg+1
248 .endr
249 .endm
250
251 #define SAVE_GPRS(start, end, base) OP_REG
252 #define REST_GPRS(start, end, base) OP_REG
253 #define SAVE_GPR(n, base) SAVE_G
254 #define REST_GPR(n, base) REST_G
255
256 /* prom handles the jump into and return from
257 is loaded in r3. */
258 .globl prom
259 prom:
260 mflr r0
261 std r0,16(r1)
262 stdu r1,-PROM_FRAME_SIZE(r1) /* Sav
263
264 SAVE_GPR(2, r1)
265 SAVE_GPRS(13, 31, r1)
266 mfcr r10
267 std r10,8*32(r1)
268 mfmsr r10
269 std r10,8*33(r1)
270
271 /* remove MSR_LE from msr but keep MSR
272 mfmsr r10
273 rldicr r10,r10,0,62
274 mtsrr1 r10
275
276 /* Load FW address, set LR to label 1,
277 bcl 20,31,0f
278 0: mflr r10
279 addi r11,r10,(1f-0b)
280 mtlr r11
281
282 ld r10,(p_prom-0b)(r10)
283 mtsrr0 r10
284
285 rfid
286
287 1: /* Return from OF */
288 FIXUP_ENDIAN
289
290 /* Restore registers and return. */
291 rldicl r1,r1,0,32
292
293 /* Restore the MSR (back to 64 bits) *
294 ld r10,8*(33)(r1)
295 mtmsr r10
296 isync
297
298 /* Restore other registers */
299 REST_GPR(2, r1)
300 REST_GPRS(13, 31, r1)
301 ld r10,8*32(r1)
302 mtcr r10
303
304 addi r1,r1,PROM_FRAME_SIZE
305 ld r0,16(r1)
306 mtlr r0
307 blr
308 #endif
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