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2023-12-11 d2ccde1c8e90d38cee87a1b0309ad2827f3fd30d 
 kernel/arch/riscv/kernel/head.S
....@@ -1,17 +1,8 @@
1
+/* SPDX-License-Identifier: GPL-2.0-only */
12 /*
23  * Copyright (C) 2012 Regents of the University of California
3
- *
4
- *   This program is free software; you can redistribute it and/or
5
- *   modify it under the terms of the GNU General Public License
6
- *   as published by the Free Software Foundation, version 2.
7
- *
8
- *   This program is distributed in the hope that it will be useful,
9
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of
10
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11
- *   GNU General Public License for more details.
124  */
135 
14
-#include <asm/thread_info.h>
156 #include <asm/asm-offsets.h>
167 #include <asm/asm.h>
178 #include <linux/init.h>
....@@ -19,11 +10,213 @@
1910 #include <asm/thread_info.h>
2011 #include <asm/page.h>
2112 #include <asm/csr.h>
13
+#include <asm/hwcap.h>
14
+#include <asm/image.h>
15
+#include "efi-header.S"
2216 
23
-__INIT
17
+__HEAD
2418 ENTRY(_start)
19
+	/*
20
+	 * Image header expected by Linux boot-loaders. The image header data
21
+	 * structure is described in asm/image.h.
22
+	 * Do not modify it without modifying the structure and all bootloaders
23
+	 * that expects this header format!!
24
+	 */
25
+#ifdef CONFIG_EFI
26
+	/*
27
+	 * This instruction decodes to "MZ" ASCII required by UEFI.
28
+	 */
29
+	c.li s4,-13
30
+	j _start_kernel
31
+#else
32
+	/* jump to start kernel */
33
+	j _start_kernel
34
+	/* reserved */
35
+	.word 0
36
+#endif
37
+	.balign 8
38
+#ifdef CONFIG_RISCV_M_MODE
39
+	/* Image load offset (0MB) from start of RAM for M-mode */
40
+	.dword 0
41
+#else
42
+#if __riscv_xlen == 64
43
+	/* Image load offset(2MB) from start of RAM */
44
+	.dword 0x200000
45
+#else
46
+	/* Image load offset(4MB) from start of RAM */
47
+	.dword 0x400000
48
+#endif
49
+#endif
50
+	/* Effective size of kernel image */
51
+	.dword _end - _start
52
+	.dword __HEAD_FLAGS
53
+	.word RISCV_HEADER_VERSION
54
+	.word 0
55
+	.dword 0
56
+	.ascii RISCV_IMAGE_MAGIC
57
+	.balign 4
58
+	.ascii RISCV_IMAGE_MAGIC2
59
+#ifdef CONFIG_EFI
60
+	.word pe_head_start - _start
61
+pe_head_start:
62
+
63
+	__EFI_PE_HEADER
64
+#else
65
+	.word 0
66
+#endif
67
+
68
+.align 2
69
+#ifdef CONFIG_MMU
70
+relocate:
71
+	/* Relocate return address */
72
+	li a1, PAGE_OFFSET
73
+	la a2, _start
74
+	sub a1, a1, a2
75
+	add ra, ra, a1
76
+
77
+	/* Point stvec to virtual address of intruction after satp write */
78
+	la a2, 1f
79
+	add a2, a2, a1
80
+	csrw CSR_TVEC, a2
81
+
82
+	/* Compute satp for kernel page tables, but don't load it yet */
83
+	srl a2, a0, PAGE_SHIFT
84
+	li a1, SATP_MODE
85
+	or a2, a2, a1
86
+
87
+	/*
88
+	 * Load trampoline page directory, which will cause us to trap to
89
+	 * stvec if VA != PA, or simply fall through if VA == PA.  We need a
90
+	 * full fence here because setup_vm() just wrote these PTEs and we need
91
+	 * to ensure the new translations are in use.
92
+	 */
93
+	la a0, trampoline_pg_dir
94
+	srl a0, a0, PAGE_SHIFT
95
+	or a0, a0, a1
96
+	sfence.vma
97
+	csrw CSR_SATP, a0
98
+.align 2
99
+1:
100
+	/* Set trap vector to spin forever to help debug */
101
+	la a0, .Lsecondary_park
102
+	csrw CSR_TVEC, a0
103
+
104
+	/* Reload the global pointer */
105
+.option push
106
+.option norelax
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+	la gp, __global_pointer$
108
+.option pop
109
+
110
+	/*
111
+	 * Switch to kernel page tables.  A full fence is necessary in order to
112
+	 * avoid using the trampoline translations, which are only correct for
113
+	 * the first superpage.  Fetching the fence is guarnteed to work
114
+	 * because that first superpage is translated the same way.
115
+	 */
116
+	csrw CSR_SATP, a2
117
+	sfence.vma
118
+
119
+	ret
120
+#endif /* CONFIG_MMU */
121
+#ifdef CONFIG_SMP
122
+	.global secondary_start_sbi
123
+secondary_start_sbi:
25124 	/* Mask all interrupts */
26
-	csrw sie, zero
125
+	csrw CSR_IE, zero
126
+	csrw CSR_IP, zero
127
+
128
+	/* Load the global pointer */
129
+	.option push
130
+	.option norelax
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+		la gp, __global_pointer$
132
+	.option pop
133
+
134
+	/*
135
+	 * Disable FPU to detect illegal usage of
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+	 * floating point in kernel space
137
+	 */
138
+	li t0, SR_FS
139
+	csrc CSR_STATUS, t0
140
+
141
+	/* Set trap vector to spin forever to help debug */
142
+	la a3, .Lsecondary_park
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+	csrw CSR_TVEC, a3
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+
145
+	slli a3, a0, LGREG
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+	la a4, __cpu_up_stack_pointer
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+	la a5, __cpu_up_task_pointer
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+	add a4, a3, a4
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+	add a5, a3, a5
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+	REG_L sp, (a4)
151
+	REG_L tp, (a5)
152
+
153
+	.global secondary_start_common
154
+secondary_start_common:
155
+
156
+#ifdef CONFIG_MMU
157
+	/* Enable virtual memory and relocate to virtual address */
158
+	la a0, swapper_pg_dir
159
+	call relocate
160
+#endif
161
+	call setup_trap_vector
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+	tail smp_callin
163
+#endif /* CONFIG_SMP */
164
+
165
+.align 2
166
+setup_trap_vector:
167
+	/* Set trap vector to exception handler */
168
+	la a0, handle_exception
169
+	csrw CSR_TVEC, a0
170
+
171
+	/*
172
+	 * Set sup0 scratch register to 0, indicating to exception vector that
173
+	 * we are presently executing in kernel.
174
+	 */
175
+	csrw CSR_SCRATCH, zero
176
+	ret
177
+
178
+.align 2
179
+.Lsecondary_park:
180
+	/* We lack SMP support or have too many harts, so park this hart */
181
+	wfi
182
+	j .Lsecondary_park
183
+
184
+END(_start)
185
+
186
+	__INIT
187
+ENTRY(_start_kernel)
188
+	/* Mask all interrupts */
189
+	csrw CSR_IE, zero
190
+	csrw CSR_IP, zero
191
+
192
+#ifdef CONFIG_RISCV_M_MODE
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+	/* flush the instruction cache */
194
+	fence.i
195
+
196
+	/* Reset all registers except ra, a0, a1 */
197
+	call reset_regs
198
+
199
+	/*
200
+	 * Setup a PMP to permit access to all of memory.  Some machines may
201
+	 * not implement PMPs, so we set up a quick trap handler to just skip
202
+	 * touching the PMPs on any trap.
203
+	 */
204
+	la a0, pmp_done
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+	csrw CSR_TVEC, a0
206
+
207
+	li a0, -1
208
+	csrw CSR_PMPADDR0, a0
209
+	li a0, (PMP_A_NAPOT | PMP_R | PMP_W | PMP_X)
210
+	csrw CSR_PMPCFG0, a0
211
+.align 2
212
+pmp_done:
213
+
214
+	/*
215
+	 * The hartid in a0 is expected later on, and we have no firmware
216
+	 * to hand it to us.
217
+	 */
218
+	csrr a0, CSR_MHARTID
219
+#endif /* CONFIG_RISCV_M_MODE */
27220 
28221 	/* Load the global pointer */
29222 .option push
....@@ -36,7 +229,14 @@
36229 	 * floating point in kernel space
37230 	 */
38231 	li t0, SR_FS
39
-	csrc sstatus, t0
232
+	csrc CSR_STATUS, t0
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+
234
+#ifdef CONFIG_SMP
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+	li t0, CONFIG_NR_CPUS
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+	blt a0, t0, .Lgood_cores
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+	tail .Lsecondary_park
238
+.Lgood_cores:
239
+#endif
40240 
41241 	/* Pick one hart to run the main boot sequence */
42242 	la a3, hart_lottery
....@@ -44,81 +244,50 @@
44244 	amoadd.w a3, a2, (a3)
45245 	bnez a3, .Lsecondary_start
46246 
247
+	/* Clear BSS for flat non-ELF images */
248
+	la a3, __bss_start
249
+	la a4, __bss_stop
250
+	ble a4, a3, clear_bss_done
251
+clear_bss:
252
+	REG_S zero, (a3)
253
+	add a3, a3, RISCV_SZPTR
254
+	blt a3, a4, clear_bss
255
+clear_bss_done:
256
+
47257 	/* Save hart ID and DTB physical address */
48258 	mv s0, a0
49259 	mv s1, a1
260
+	la a2, boot_cpu_hartid
261
+	REG_S a0, (a2)
50262 
51263 	/* Initialize page tables and relocate to virtual addresses */
264
+	la tp, init_task
52265 	la sp, init_thread_union + THREAD_SIZE
266
+	mv a0, s1
53267 	call setup_vm
268
+#ifdef CONFIG_MMU
269
+	la a0, early_pg_dir
54270 	call relocate
271
+#endif /* CONFIG_MMU */
55272 
273
+	call setup_trap_vector
56274 	/* Restore C environment */
57275 	la tp, init_task
58
-	sw s0, TASK_TI_CPU(tp)
276
+	sw zero, TASK_TI_CPU(tp)
277
+	la sp, init_thread_union + THREAD_SIZE
59278 
60
-	la sp, init_thread_union
61
-	li a0, ASM_THREAD_SIZE
62
-	add sp, sp, a0
63
-
279
+#ifdef CONFIG_KASAN
280
+	call kasan_early_init
281
+#endif
64282 	/* Start the kernel */
65
-	mv a0, s0
66
-	mv a1, s1
67
-	call parse_dtb
283
+	call soc_early_init
68284 	tail start_kernel
69
-
70
-relocate:
71
-	/* Relocate return address */
72
-	li a1, PAGE_OFFSET
73
-	la a0, _start
74
-	sub a1, a1, a0
75
-	add ra, ra, a1
76
-
77
-	/* Point stvec to virtual address of intruction after satp write */
78
-	la a0, 1f
79
-	add a0, a0, a1
80
-	csrw stvec, a0
81
-
82
-	/* Compute satp for kernel page tables, but don't load it yet */
83
-	la a2, swapper_pg_dir
84
-	srl a2, a2, PAGE_SHIFT
85
-	li a1, SATP_MODE
86
-	or a2, a2, a1
87
-
88
-	/*
89
-	 * Load trampoline page directory, which will cause us to trap to
90
-	 * stvec if VA != PA, or simply fall through if VA == PA
91
-	 */
92
-	la a0, trampoline_pg_dir
93
-	srl a0, a0, PAGE_SHIFT
94
-	or a0, a0, a1
95
-	sfence.vma
96
-	csrw sptbr, a0
97
-.align 2
98
-1:
99
-	/* Set trap vector to spin forever to help debug */
100
-	la a0, .Lsecondary_park
101
-	csrw stvec, a0
102
-
103
-	/* Reload the global pointer */
104
-.option push
105
-.option norelax
106
-	la gp, __global_pointer$
107
-.option pop
108
-
109
-	/* Switch to kernel page tables */
110
-	csrw sptbr, a2
111
-
112
-	ret
113285 
114286 .Lsecondary_start:
115287 #ifdef CONFIG_SMP
116
-	li a1, CONFIG_NR_CPUS
117
-	bgeu a0, a1, .Lsecondary_park
118
-
119288 	/* Set trap vector to spin forever to help debug */
120289 	la a3, .Lsecondary_park
121
-	csrw stvec, a3
290
+	csrw CSR_TVEC, a3
122291 
123292 	slli a3, a0, LGREG
124293 	la a1, __cpu_up_stack_pointer
....@@ -138,18 +307,89 @@
138307 	beqz tp, .Lwait_for_cpu_up
139308 	fence
140309 
141
-	/* Enable virtual memory and relocate to virtual address */
142
-	call relocate
143
-
144
-	tail smp_callin
310
+	tail secondary_start_common
145311 #endif
146312 
147
-.align 2
148
-.Lsecondary_park:
149
-	/* We lack SMP support or have too many harts, so park this hart */
150
-	wfi
151
-	j .Lsecondary_park
152
-END(_start)
313
+END(_start_kernel)
314
+
315
+#ifdef CONFIG_RISCV_M_MODE
316
+ENTRY(reset_regs)
317
+	li	sp, 0
318
+	li	gp, 0
319
+	li	tp, 0
320
+	li	t0, 0
321
+	li	t1, 0
322
+	li	t2, 0
323
+	li	s0, 0
324
+	li	s1, 0
325
+	li	a2, 0
326
+	li	a3, 0
327
+	li	a4, 0
328
+	li	a5, 0
329
+	li	a6, 0
330
+	li	a7, 0
331
+	li	s2, 0
332
+	li	s3, 0
333
+	li	s4, 0
334
+	li	s5, 0
335
+	li	s6, 0
336
+	li	s7, 0
337
+	li	s8, 0
338
+	li	s9, 0
339
+	li	s10, 0
340
+	li	s11, 0
341
+	li	t3, 0
342
+	li	t4, 0
343
+	li	t5, 0
344
+	li	t6, 0
345
+	csrw	CSR_SCRATCH, 0
346
+
347
+#ifdef CONFIG_FPU
348
+	csrr	t0, CSR_MISA
349
+	andi	t0, t0, (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D)
350
+	beqz	t0, .Lreset_regs_done
351
+
352
+	li	t1, SR_FS
353
+	csrs	CSR_STATUS, t1
354
+	fmv.s.x	f0, zero
355
+	fmv.s.x	f1, zero
356
+	fmv.s.x	f2, zero
357
+	fmv.s.x	f3, zero
358
+	fmv.s.x	f4, zero
359
+	fmv.s.x	f5, zero
360
+	fmv.s.x	f6, zero
361
+	fmv.s.x	f7, zero
362
+	fmv.s.x	f8, zero
363
+	fmv.s.x	f9, zero
364
+	fmv.s.x	f10, zero
365
+	fmv.s.x	f11, zero
366
+	fmv.s.x	f12, zero
367
+	fmv.s.x	f13, zero
368
+	fmv.s.x	f14, zero
369
+	fmv.s.x	f15, zero
370
+	fmv.s.x	f16, zero
371
+	fmv.s.x	f17, zero
372
+	fmv.s.x	f18, zero
373
+	fmv.s.x	f19, zero
374
+	fmv.s.x	f20, zero
375
+	fmv.s.x	f21, zero
376
+	fmv.s.x	f22, zero
377
+	fmv.s.x	f23, zero
378
+	fmv.s.x	f24, zero
379
+	fmv.s.x	f25, zero
380
+	fmv.s.x	f26, zero
381
+	fmv.s.x	f27, zero
382
+	fmv.s.x	f28, zero
383
+	fmv.s.x	f29, zero
384
+	fmv.s.x	f30, zero
385
+	fmv.s.x	f31, zero
386
+	csrw	fcsr, 0
387
+	/* note that the caller must clear SR_FS */
388
+#endif /* CONFIG_FPU */
389
+.Lreset_regs_done:
390
+	ret
391
+END(reset_regs)
392
+#endif /* CONFIG_RISCV_M_MODE */
153393 
154394 __PAGE_ALIGNED_BSS
155395 	/* Empty zero page */