1 /* SPDX-License-Identifier: GPL-2.0-only */ <<
2 /* 1 /*
3 * Copyright (C) 2012 Regents of the Universit !! 2 * This file is subject to the terms and conditions of the GNU General Public
>> 3 * License. See the file "COPYING" in the main directory of this archive
>> 4 * for more details.
>> 5 *
>> 6 * Copyright (C) 1994, 1995 Waldorf Electronics
>> 7 * Written by Ralf Baechle and Andreas Busse
>> 8 * Copyright (C) 1994 - 99, 2003, 06 Ralf Baechle
>> 9 * Copyright (C) 1996 Paul M. Antoine
>> 10 * Modified for DECStation and hence R3000 support by Paul M. Antoine
>> 11 * Further modifications by David S. Miller and Harald Koerfgen
>> 12 * Copyright (C) 1999 Silicon Graphics, Inc.
>> 13 * Kevin Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
>> 14 * Copyright (C) 2000 MIPS Technologies, Inc. All rights reserved.
4 */ 15 */
>> 16 #include <linux/init.h>
>> 17 #include <linux/threads.h>
5 18
6 #include <asm/asm-offsets.h> !! 19 #include <asm/addrspace.h>
7 #include <asm/asm.h> 20 #include <asm/asm.h>
8 #include <linux/init.h> !! 21 #include <asm/asmmacro.h>
9 #include <linux/linkage.h> !! 22 #include <asm/irqflags.h>
10 #include <asm/thread_info.h> !! 23 #include <asm/regdef.h>
11 #include <asm/page.h> !! 24 #include <asm/mipsregs.h>
12 #include <asm/pgtable.h> !! 25 #include <asm/stackframe.h>
13 #include <asm/csr.h> !! 26
14 #include <asm/hwcap.h> !! 27 #include <kernel-entry-init.h>
15 #include <asm/image.h> <<
16 #include <asm/scs.h> <<
17 #include <asm/xip_fixup.h> <<
18 #include "efi-header.S" <<
19 28
20 __HEAD <<
21 SYM_CODE_START(_start) <<
22 /* <<
23 * Image header expected by Linux boot <<
24 * structure is described in asm/image <<
25 * Do not modify it without modifying <<
26 * that expects this header format!! <<
27 */ <<
28 #ifdef CONFIG_EFI <<
29 /* 29 /*
30 * This instruction decodes to "MZ" AS !! 30 * For the moment disable interrupts, mark the kernel mode and
>> 31 * set ST0_KX so that the CPU does not spit fire when using
>> 32 * 64-bit addresses. A full initialization of the CPU's status
>> 33 * register is done later in per_cpu_trap_init().
31 */ 34 */
32 c.li s4,-13 !! 35 .macro setup_c0_status set clr
33 j _start_kernel !! 36 .set push
34 #else !! 37 mfc0 t0, CP0_STATUS
35 /* jump to start kernel */ !! 38 or t0, ST0_KERNEL_CUMASK|\set|0x1f|\clr
36 j _start_kernel !! 39 xor t0, 0x1f|\clr
37 /* reserved */ !! 40 mtc0 t0, CP0_STATUS
38 .word 0 !! 41 .set noreorder
39 #endif !! 42 sll zero,3 # ehb
40 .balign 8 !! 43 .set pop
41 #ifdef CONFIG_RISCV_M_MODE !! 44 .endm
42 /* Image load offset (0MB) from start !! 45
43 .dword 0 !! 46 .macro setup_c0_status_pri
44 #else !! 47 #ifdef CONFIG_64BIT
45 #if __riscv_xlen == 64 !! 48 setup_c0_status ST0_KX 0
46 /* Image load offset(2MB) from start o <<
47 .dword 0x200000 <<
48 #else 49 #else
49 /* Image load offset(4MB) from start o !! 50 setup_c0_status 0 0
50 .dword 0x400000 <<
51 #endif 51 #endif
52 #endif !! 52 .endm
53 /* Effective size of kernel image */ <<
54 .dword _end - _start <<
55 .dword __HEAD_FLAGS <<
56 .word RISCV_HEADER_VERSION <<
57 .word 0 <<
58 .dword 0 <<
59 .ascii RISCV_IMAGE_MAGIC <<
60 .balign 4 <<
61 .ascii RISCV_IMAGE_MAGIC2 <<
62 #ifdef CONFIG_EFI <<
63 .word pe_head_start - _start <<
64 pe_head_start: <<
65 53
66 __EFI_PE_HEADER !! 54 .macro setup_c0_status_sec
>> 55 #ifdef CONFIG_64BIT
>> 56 setup_c0_status ST0_KX ST0_BEV
67 #else 57 #else
68 .word 0 !! 58 setup_c0_status 0 ST0_BEV
69 #endif 59 #endif
>> 60 .endm
70 61
71 .align 2 !! 62 #ifndef CONFIG_NO_EXCEPT_FILL
72 #ifdef CONFIG_MMU <<
73 .global relocate_enable_mmu <<
74 relocate_enable_mmu: <<
75 /* Relocate return address */ <<
76 la a1, kernel_map <<
77 XIP_FIXUP_OFFSET a1 <<
78 REG_L a1, KERNEL_MAP_VIRT_ADDR(a1) <<
79 la a2, _start <<
80 sub a1, a1, a2 <<
81 add ra, ra, a1 <<
82 <<
83 /* Point stvec to virtual address of i <<
84 la a2, 1f <<
85 add a2, a2, a1 <<
86 csrw CSR_TVEC, a2 <<
87 <<
88 /* Compute satp for kernel page tables <<
89 srl a2, a0, PAGE_SHIFT <<
90 la a1, satp_mode <<
91 XIP_FIXUP_OFFSET a1 <<
92 REG_L a1, 0(a1) <<
93 or a2, a2, a1 <<
94 <<
95 /* 63 /*
96 * Load trampoline page directory, whi !! 64 * Reserved space for exception handlers.
97 * stvec if VA != PA, or simply fall t !! 65 * Necessary for machines which link their kernels at KSEG0.
98 * full fence here because setup_vm() <<
99 * to ensure the new translations are <<
100 */ 66 */
101 la a0, trampoline_pg_dir !! 67 .fill 0x400
102 XIP_FIXUP_OFFSET a0 <<
103 srl a0, a0, PAGE_SHIFT <<
104 or a0, a0, a1 <<
105 sfence.vma <<
106 csrw CSR_SATP, a0 <<
107 .align 2 <<
108 1: <<
109 /* Set trap vector to spin forever to <<
110 la a0, .Lsecondary_park <<
111 csrw CSR_TVEC, a0 <<
112 <<
113 /* Reload the global pointer */ <<
114 load_global_pointer <<
115 <<
116 /* <<
117 * Switch to kernel page tables. A fu <<
118 * avoid using the trampoline translat <<
119 * the first superpage. Fetching the <<
120 * because that first superpage is tra <<
121 */ <<
122 csrw CSR_SATP, a2 <<
123 sfence.vma <<
124 <<
125 ret <<
126 #endif /* CONFIG_MMU */ <<
127 #ifdef CONFIG_SMP <<
128 .global secondary_start_sbi <<
129 secondary_start_sbi: <<
130 /* Mask all interrupts */ <<
131 csrw CSR_IE, zero <<
132 csrw CSR_IP, zero <<
133 <<
134 /* Load the global pointer */ <<
135 load_global_pointer <<
136 <<
137 /* <<
138 * Disable FPU & VECTOR to detect ille <<
139 * floating point or vector in kernel <<
140 */ <<
141 li t0, SR_FS_VS <<
142 csrc CSR_STATUS, t0 <<
143 <<
144 /* Set trap vector to spin forever to <<
145 la a3, .Lsecondary_park <<
146 csrw CSR_TVEC, a3 <<
147 <<
148 /* a0 contains the hartid & a1 contain <<
149 li a2, SBI_HART_BOOT_TASK_PTR_OFFSET <<
150 XIP_FIXUP_OFFSET a2 <<
151 add a2, a2, a1 <<
152 REG_L tp, (a2) <<
153 li a3, SBI_HART_BOOT_STACK_PTR_OFFSET <<
154 XIP_FIXUP_OFFSET a3 <<
155 add a3, a3, a1 <<
156 REG_L sp, (a3) <<
157 <<
158 .Lsecondary_start_common: <<
159 <<
160 #ifdef CONFIG_MMU <<
161 /* Enable virtual memory and relocate <<
162 la a0, swapper_pg_dir <<
163 XIP_FIXUP_OFFSET a0 <<
164 call relocate_enable_mmu <<
165 #endif 68 #endif
166 call .Lsetup_trap_vector <<
167 scs_load_current <<
168 call smp_callin <<
169 #endif /* CONFIG_SMP */ <<
170 <<
171 .align 2 <<
172 .Lsecondary_park: <<
173 /* <<
174 * Park this hart if we: <<
175 * - have too many harts on CONFIG_RI <<
176 * - receive an early trap, before se <<
177 * - fail in smp_callin(), as a succe <<
178 */ <<
179 wfi <<
180 j .Lsecondary_park <<
181 69
182 .align 2 !! 70 EXPORT(_stext)
183 .Lsetup_trap_vector: <<
184 /* Set trap vector to exception handle <<
185 la a0, handle_exception <<
186 csrw CSR_TVEC, a0 <<
187 71
>> 72 #ifdef CONFIG_BOOT_RAW
188 /* 73 /*
189 * Set sup0 scratch register to 0, ind !! 74 * Give us a fighting chance of running if execution beings at the
190 * we are presently executing in kerne !! 75 * kernel load address. This is needed because this platform does
>> 76 * not have a ELF loader yet.
191 */ 77 */
192 csrw CSR_SCRATCH, zero !! 78 FEXPORT(__kernel_entry)
193 ret !! 79 j kernel_entry
>> 80 #endif /* CONFIG_BOOT_RAW */
194 81
195 SYM_CODE_END(_start) !! 82 __REF
196 83
197 SYM_CODE_START(_start_kernel) !! 84 NESTED(kernel_entry, 16, sp) # kernel entry point
198 /* Mask all interrupts */ <<
199 csrw CSR_IE, zero <<
200 csrw CSR_IP, zero <<
201 <<
202 #ifdef CONFIG_RISCV_M_MODE <<
203 /* flush the instruction cache */ <<
204 fence.i <<
205 85
206 /* Reset all registers except ra, a0, !! 86 kernel_entry_setup # cpu specific setup
207 call reset_regs <<
208 87
209 /* !! 88 setup_c0_status_pri
210 * Setup a PMP to permit access to all <<
211 * not implement PMPs, so we set up a <<
212 * touching the PMPs on any trap. <<
213 */ <<
214 la a0, .Lpmp_done <<
215 csrw CSR_TVEC, a0 <<
216 <<
217 li a0, -1 <<
218 csrw CSR_PMPADDR0, a0 <<
219 li a0, (PMP_A_NAPOT | PMP_R | PMP_W | <<
220 csrw CSR_PMPCFG0, a0 <<
221 .align 2 <<
222 .Lpmp_done: <<
223 <<
224 /* <<
225 * The hartid in a0 is expected later <<
226 * to hand it to us. <<
227 */ <<
228 csrr a0, CSR_MHARTID <<
229 #endif /* CONFIG_RISCV_M_MODE */ <<
230 <<
231 /* Load the global pointer */ <<
232 load_global_pointer <<
233 89
234 /* !! 90 /* We might not get launched at the address the kernel is linked to,
235 * Disable FPU & VECTOR to detect ille !! 91 so we jump there. */
236 * floating point or vector in kernel !! 92 PTR_LA t0, 0f
237 */ !! 93 jr t0
238 li t0, SR_FS_VS !! 94 0:
239 csrc CSR_STATUS, t0 <<
240 95
241 #ifdef CONFIG_RISCV_BOOT_SPINWAIT !! 96 PTR_LA t0, __bss_start # clear .bss
242 li t0, CONFIG_NR_CPUS !! 97 LONG_S zero, (t0)
243 blt a0, t0, .Lgood_cores !! 98 PTR_LA t1, __bss_stop - LONGSIZE
244 tail .Lsecondary_park !! 99 1:
245 .Lgood_cores: !! 100 PTR_ADDIU t0, LONGSIZE
246 !! 101 LONG_S zero, (t0)
247 /* The lottery system is only required !! 102 bne t0, t1, 1b
248 #ifndef CONFIG_XIP_KERNEL !! 103
249 /* Pick one hart to run the main boot !! 104 LONG_S a0, fw_arg0 # firmware arguments
250 la a3, hart_lottery !! 105 LONG_S a1, fw_arg1
251 li a2, 1 !! 106 LONG_S a2, fw_arg2
252 amoadd.w a3, a2, (a3) !! 107 LONG_S a3, fw_arg3
253 bnez a3, .Lsecondary_start !! 108
254 !! 109 MTC0 zero, CP0_CONTEXT # clear context register
255 #else !! 110 #ifdef CONFIG_64BIT
256 /* hart_lottery in flash contains a ma !! 111 MTC0 zero, CP0_XCONTEXT
257 la a3, hart_lottery !! 112 #endif
258 mv a2, a3 !! 113 PTR_LA $28, init_thread_union
259 XIP_FIXUP_OFFSET a2 !! 114 /* Set the SP after an empty pt_regs. */
260 XIP_FIXUP_FLASH_OFFSET a3 !! 115 PTR_LI sp, _THREAD_SIZE - 32 - PT_SIZE
261 lw t1, (a3) !! 116 PTR_ADDU sp, $28
262 amoswap.w t0, t1, (a2) !! 117 back_to_back_c0_hazard
263 /* first time here if hart_lottery in !! 118 set_saved_sp sp, t0, t1
264 beq t0, t1, .Lsecondary_start !! 119 PTR_SUBU sp, 4 * SZREG # init stack pointer
265 !! 120
266 #endif /* CONFIG_XIP */ !! 121 #ifdef CONFIG_RELOCATABLE
267 #endif /* CONFIG_RISCV_BOOT_SPINWAIT */ !! 122 /* Copy kernel and apply the relocations */
268 !! 123 jal relocate_kernel
269 #ifdef CONFIG_XIP_KERNEL !! 124
270 la sp, _end + THREAD_SIZE !! 125 /* Repoint the sp into the new kernel image */
271 XIP_FIXUP_OFFSET sp !! 126 PTR_LI sp, _THREAD_SIZE - 32 - PT_SIZE
272 mv s0, a0 !! 127 PTR_ADDU sp, $28
273 mv s1, a1 !! 128 set_saved_sp sp, t0, t1
274 call __copy_data !! 129 PTR_SUBU sp, 4 * SZREG # init stack pointer
275 !! 130
276 /* Restore a0 & a1 copy */ !! 131 /*
277 mv a0, s0 !! 132 * relocate_kernel returns the entry point either
278 mv a1, s1 !! 133 * in the relocated kernel or the original if for
279 #endif !! 134 * some reason relocation failed - jump there now
280 !! 135 * with instruction hazard barrier because of the
281 #ifndef CONFIG_XIP_KERNEL !! 136 * newly sync'd icache.
282 /* Clear BSS for flat non-ELF images * !! 137 */
283 la a3, __bss_start !! 138 jr.hb v0
284 la a4, __bss_stop !! 139 #else /* !CONFIG_RELOCATABLE */
285 ble a4, a3, .Lclear_bss_done !! 140 j start_kernel
286 .Lclear_bss: !! 141 #endif /* !CONFIG_RELOCATABLE */
287 REG_S zero, (a3) !! 142 END(kernel_entry)
288 add a3, a3, RISCV_SZPTR <<
289 blt a3, a4, .Lclear_bss <<
290 .Lclear_bss_done: <<
291 #endif <<
292 la a2, boot_cpu_hartid <<
293 XIP_FIXUP_OFFSET a2 <<
294 REG_S a0, (a2) <<
295 <<
296 /* Initialize page tables and relocate <<
297 la tp, init_task <<
298 la sp, init_thread_union + THREAD_SIZE <<
299 XIP_FIXUP_OFFSET sp <<
300 addi sp, sp, -PT_SIZE_ON_STACK <<
301 scs_load_init_stack <<
302 #ifdef CONFIG_BUILTIN_DTB <<
303 la a0, __dtb_start <<
304 XIP_FIXUP_OFFSET a0 <<
305 #else <<
306 mv a0, a1 <<
307 #endif /* CONFIG_BUILTIN_DTB */ <<
308 /* Set trap vector to spin forever to <<
309 la a3, .Lsecondary_park <<
310 csrw CSR_TVEC, a3 <<
311 call setup_vm <<
312 #ifdef CONFIG_MMU <<
313 la a0, early_pg_dir <<
314 XIP_FIXUP_OFFSET a0 <<
315 call relocate_enable_mmu <<
316 #endif /* CONFIG_MMU */ <<
317 <<
318 call .Lsetup_trap_vector <<
319 /* Restore C environment */ <<
320 la tp, init_task <<
321 la sp, init_thread_union + THREAD_SIZE <<
322 addi sp, sp, -PT_SIZE_ON_STACK <<
323 scs_load_current <<
324 <<
325 #ifdef CONFIG_KASAN <<
326 call kasan_early_init <<
327 #endif <<
328 /* Start the kernel */ <<
329 call soc_early_init <<
330 tail start_kernel <<
331 <<
332 #ifdef CONFIG_RISCV_BOOT_SPINWAIT <<
333 .Lsecondary_start: <<
334 /* Set trap vector to spin forever to <<
335 la a3, .Lsecondary_park <<
336 csrw CSR_TVEC, a3 <<
337 <<
338 slli a3, a0, LGREG <<
339 la a1, __cpu_spinwait_stack_pointer <<
340 XIP_FIXUP_OFFSET a1 <<
341 la a2, __cpu_spinwait_task_pointer <<
342 XIP_FIXUP_OFFSET a2 <<
343 add a1, a3, a1 <<
344 add a2, a3, a2 <<
345 <<
346 /* <<
347 * This hart didn't win the lottery, s <<
348 * get far enough along the boot proce <<
349 */ <<
350 .Lwait_for_cpu_up: <<
351 /* FIXME: We should WFI to save some e <<
352 REG_L sp, (a1) <<
353 REG_L tp, (a2) <<
354 beqz sp, .Lwait_for_cpu_up <<
355 beqz tp, .Lwait_for_cpu_up <<
356 fence <<
357 <<
358 tail .Lsecondary_start_common <<
359 #endif /* CONFIG_RISCV_BOOT_SPINWAIT */ <<
360 <<
361 SYM_CODE_END(_start_kernel) <<
362 <<
363 #ifdef CONFIG_RISCV_M_MODE <<
364 SYM_CODE_START_LOCAL(reset_regs) <<
365 li sp, 0 <<
366 li gp, 0 <<
367 li tp, 0 <<
368 li t0, 0 <<
369 li t1, 0 <<
370 li t2, 0 <<
371 li s0, 0 <<
372 li s1, 0 <<
373 li a2, 0 <<
374 li a3, 0 <<
375 li a4, 0 <<
376 li a5, 0 <<
377 li a6, 0 <<
378 li a7, 0 <<
379 li s2, 0 <<
380 li s3, 0 <<
381 li s4, 0 <<
382 li s5, 0 <<
383 li s6, 0 <<
384 li s7, 0 <<
385 li s8, 0 <<
386 li s9, 0 <<
387 li s10, 0 <<
388 li s11, 0 <<
389 li t3, 0 <<
390 li t4, 0 <<
391 li t5, 0 <<
392 li t6, 0 <<
393 csrw CSR_SCRATCH, 0 <<
394 <<
395 #ifdef CONFIG_FPU <<
396 csrr t0, CSR_MISA <<
397 andi t0, t0, (COMPAT_HWCAP_ISA_F | <<
398 beqz t0, .Lreset_regs_done_fpu <<
399 <<
400 li t1, SR_FS <<
401 csrs CSR_STATUS, t1 <<
402 fmv.s.x f0, zero <<
403 fmv.s.x f1, zero <<
404 fmv.s.x f2, zero <<
405 fmv.s.x f3, zero <<
406 fmv.s.x f4, zero <<
407 fmv.s.x f5, zero <<
408 fmv.s.x f6, zero <<
409 fmv.s.x f7, zero <<
410 fmv.s.x f8, zero <<
411 fmv.s.x f9, zero <<
412 fmv.s.x f10, zero <<
413 fmv.s.x f11, zero <<
414 fmv.s.x f12, zero <<
415 fmv.s.x f13, zero <<
416 fmv.s.x f14, zero <<
417 fmv.s.x f15, zero <<
418 fmv.s.x f16, zero <<
419 fmv.s.x f17, zero <<
420 fmv.s.x f18, zero <<
421 fmv.s.x f19, zero <<
422 fmv.s.x f20, zero <<
423 fmv.s.x f21, zero <<
424 fmv.s.x f22, zero <<
425 fmv.s.x f23, zero <<
426 fmv.s.x f24, zero <<
427 fmv.s.x f25, zero <<
428 fmv.s.x f26, zero <<
429 fmv.s.x f27, zero <<
430 fmv.s.x f28, zero <<
431 fmv.s.x f29, zero <<
432 fmv.s.x f30, zero <<
433 fmv.s.x f31, zero <<
434 csrw fcsr, 0 <<
435 /* note that the caller must clear SR_ <<
436 .Lreset_regs_done_fpu: <<
437 #endif /* CONFIG_FPU */ <<
438 <<
439 #ifdef CONFIG_RISCV_ISA_V <<
440 csrr t0, CSR_MISA <<
441 li t1, COMPAT_HWCAP_ISA_V <<
442 and t0, t0, t1 <<
443 beqz t0, .Lreset_regs_done_vector <<
444 143
445 /* !! 144 #ifdef CONFIG_SMP
446 * Clear vector registers and reset vc !! 145 /*
447 * VLMAX has a defined value, VLEN is !! 146 * SMP slave cpus entry point. Board specific code for bootstrap calls this
448 * and this form of vsetvli is defined !! 147 * function after setting up the stack and gp registers.
449 */ !! 148 */
450 li t1, SR_VS !! 149 NESTED(smp_bootstrap, 16, sp)
451 csrs CSR_STATUS, t1 !! 150 smp_slave_setup
452 csrs CSR_VCSR, x0 !! 151 setup_c0_status_sec
453 vsetvli t1, x0, e8, m8, ta, ma !! 152 j start_secondary
454 vmv.v.i v0, 0 !! 153 END(smp_bootstrap)
455 vmv.v.i v8, 0 !! 154 #endif /* CONFIG_SMP */
456 vmv.v.i v16, 0 <<
457 vmv.v.i v24, 0 <<
458 /* note that the caller must clear SR_ <<
459 .Lreset_regs_done_vector: <<
460 #endif /* CONFIG_RISCV_ISA_V */ <<
461 ret <<
462 SYM_CODE_END(reset_regs) <<
463 #endif /* CONFIG_RISCV_M_MODE */ <<
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