1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
|
/*
* Copyright (c) 2006-2018, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2013-07-05 Bernard the first version
* 2018-11-22 Jesven in the interrupt context, use rt_scheduler_do_irq_switch checks
* and switches to a new thread
*/
#include "rtconfig.h"
.equ Mode_USR, 0x10
.equ Mode_FIQ, 0x11
.equ Mode_IRQ, 0x12
.equ Mode_SVC, 0x13
.equ Mode_ABT, 0x17
.equ Mode_UND, 0x1B
.equ Mode_SYS, 0x1F
.equ I_Bit, 0x80 @ when I bit is set, IRQ is disabled
.equ F_Bit, 0x40 @ when F bit is set, FIQ is disabled
.equ UND_Stack_Size, 0x00000000
.equ SVC_Stack_Size, 0x00000400
.equ ABT_Stack_Size, 0x00000000
.equ RT_FIQ_STACK_PGSZ, 0x00000000
.equ RT_IRQ_STACK_PGSZ, 0x00000800
.equ USR_Stack_Size, 0x00000400
#define ISR_Stack_Size (UND_Stack_Size + SVC_Stack_Size + ABT_Stack_Size + \
RT_FIQ_STACK_PGSZ + RT_IRQ_STACK_PGSZ)
.section .data.share.isr
/* stack */
.globl stack_start
.globl stack_top
stack_start:
.rept ISR_Stack_Size
.byte 0
.endr
stack_top:
.text
/* reset entry */
.globl _reset
_reset:
/* set the cpu to SVC32 mode and disable interrupt */
cps #Mode_SVC
/* disable the data alignment check */
mrc p15, 0, r1, c1, c0, 0
bic r1, #(1<<1)
mcr p15, 0, r1, c1, c0, 0
/* setup stack */
bl stack_setup
/* clear .bss */
mov r0,#0 /* get a zero */
ldr r1,=__bss_start /* bss start */
ldr r2,=__bss_end /* bss end */
bss_loop:
cmp r1,r2 /* check if data to clear */
strlo r0,[r1],#4 /* clear 4 bytes */
blo bss_loop /* loop until done */
#ifdef RT_USING_SMP
mrc p15, 0, r1, c1, c0, 1
mov r0, #(1<<6)
orr r1, r0
mcr p15, 0, r1, c1, c0, 1 //enable smp
#endif
/* initialize the mmu table and enable mmu */
ldr r0, =platform_mem_desc
ldr r1, =platform_mem_desc_size
ldr r1, [r1]
bl rt_hw_init_mmu_table
bl rt_hw_mmu_init
/* call C++ constructors of global objects */
ldr r0, =__ctors_start__
ldr r1, =__ctors_end__
ctor_loop:
cmp r0, r1
beq ctor_end
ldr r2, [r0], #4
stmfd sp!, {r0-r1}
mov lr, pc
bx r2
ldmfd sp!, {r0-r1}
b ctor_loop
ctor_end:
/* start RT-Thread Kernel */
ldr pc, _rtthread_startup
_rtthread_startup:
.word rtthread_startup
stack_setup:
ldr r0, =stack_top
@ Set the startup stack for svc
mov sp, r0
@ Enter Undefined Instruction Mode and set its Stack Pointer
msr cpsr_c, #Mode_UND|I_Bit|F_Bit
mov sp, r0
sub r0, r0, #UND_Stack_Size
@ Enter Abort Mode and set its Stack Pointer
msr cpsr_c, #Mode_ABT|I_Bit|F_Bit
mov sp, r0
sub r0, r0, #ABT_Stack_Size
@ Enter FIQ Mode and set its Stack Pointer
msr cpsr_c, #Mode_FIQ|I_Bit|F_Bit
mov sp, r0
sub r0, r0, #RT_FIQ_STACK_PGSZ
@ Enter IRQ Mode and set its Stack Pointer
msr cpsr_c, #Mode_IRQ|I_Bit|F_Bit
mov sp, r0
sub r0, r0, #RT_IRQ_STACK_PGSZ
/* come back to SVC mode */
msr cpsr_c, #Mode_SVC|I_Bit|F_Bit
bx lr
/* exception handlers: undef, swi, padt, dabt, resv, irq, fiq */
.section .text.isr, "ax"
.align 5
.globl vector_fiq
vector_fiq:
stmfd sp!,{r0-r7,lr}
bl rt_hw_trap_fiq
ldmfd sp!,{r0-r7,lr}
subs pc, lr, #4
.globl rt_interrupt_enter
.globl rt_interrupt_leave
.globl rt_thread_switch_interrupt_flag
.globl rt_interrupt_from_thread
.globl rt_interrupt_to_thread
.globl rt_current_thread
.globl vmm_thread
.globl vmm_virq_check
.align 5
.globl vector_irq
vector_irq:
#ifdef RT_USING_SMP
clrex
stmfd sp!, {r0, r1}
cps #Mode_SVC
mov r0, sp /* svc_sp */
mov r1, lr /* svc_lr */
cps #Mode_IRQ
sub lr, #4
stmfd r0!, {r1, lr} /* svc_lr, svc_pc */
stmfd r0!, {r2 - r12}
ldmfd sp!, {r1, r2} /* original r0, r1 */
stmfd r0!, {r1 - r2}
mrs r1, spsr /* original mode */
stmfd r0!, {r1}
#ifdef RT_USING_LWP
stmfd r0, {r13, r14}^ /* usr_sp, usr_lr */
sub r0, #8
#endif
/* now irq stack is clean */
/* r0 is task svc_sp */
/* backup r0 -> r8 */
mov r8, r0
bl rt_interrupt_enter
bl rt_hw_trap_irq
bl rt_interrupt_leave
cps #Mode_SVC
mov sp, r8
mov r0, r8
bl rt_scheduler_do_irq_switch
b rt_hw_context_switch_exit
#else
stmfd sp!, {r0-r12,lr}
bl rt_interrupt_enter
bl rt_hw_trap_irq
bl rt_interrupt_leave
@ if rt_thread_switch_interrupt_flag set, jump to
@ rt_hw_context_switch_interrupt_do and don't return
ldr r0, =rt_thread_switch_interrupt_flag
ldr r1, [r0]
cmp r1, #1
beq rt_hw_context_switch_interrupt_do
ldmfd sp!, {r0-r12,lr}
subs pc, lr, #4
rt_hw_context_switch_interrupt_do:
mov r1, #0 @ clear flag
str r1, [r0]
mov r1, sp @ r1 point to {r0-r3} in stack
add sp, sp, #4*4
ldmfd sp!, {r4-r12,lr}@ reload saved registers
mrs r0, spsr @ get cpsr of interrupt thread
sub r2, lr, #4 @ save old task's pc to r2
@ Switch to SVC mode with no interrupt. If the usr mode guest is
@ interrupted, this will just switch to the stack of kernel space.
@ save the registers in kernel space won't trigger data abort.
msr cpsr_c, #I_Bit|F_Bit|Mode_SVC
stmfd sp!, {r2} @ push old task's pc
stmfd sp!, {r4-r12,lr}@ push old task's lr,r12-r4
ldmfd r1, {r1-r4} @ restore r0-r3 of the interrupt thread
stmfd sp!, {r1-r4} @ push old task's r0-r3
stmfd sp!, {r0} @ push old task's cpsr
#ifdef RT_USING_LWP
stmfd sp, {r13, r14}^ @push usr_sp, usr_lr
sub sp, #8
#endif
ldr r4, =rt_interrupt_from_thread
ldr r5, [r4]
str sp, [r5] @ store sp in preempted tasks's TCB
ldr r6, =rt_interrupt_to_thread
ldr r6, [r6]
ldr sp, [r6] @ get new task's stack pointer
#ifdef RT_USING_LWP
ldmfd sp, {r13, r14}^ @pop usr_sp, usr_lr
add sp, #8
#endif
ldmfd sp!, {r4} @ pop new task's cpsr to spsr
msr spsr_cxsf, r4
ldmfd sp!, {r0-r12,lr,pc}^ @ pop new task's r0-r12,lr & pc, copy spsr to cpsr
#endif
.macro push_svc_reg
sub sp, sp, #17 * 4 @/* Sizeof(struct rt_hw_exp_stack) */
stmia sp, {r0 - r12} @/* Calling r0-r12 */
mov r0, sp
mrs r6, spsr @/* Save CPSR */
str lr, [r0, #15*4] @/* Push PC */
str r6, [r0, #16*4] @/* Push CPSR */
cps #Mode_SVC
str sp, [r0, #13*4] @/* Save calling SP */
str lr, [r0, #14*4] @/* Save calling PC */
.endm
.align 5
.weak vector_swi
vector_swi:
push_svc_reg
bl rt_hw_trap_swi
b .
.align 5
.globl vector_undef
vector_undef:
push_svc_reg
bl rt_hw_trap_undef
b .
.align 5
.globl vector_pabt
vector_pabt:
push_svc_reg
bl rt_hw_trap_pabt
b .
.align 5
.globl vector_dabt
vector_dabt:
push_svc_reg
bl rt_hw_trap_dabt
b .
.align 5
.globl vector_resv
vector_resv:
push_svc_reg
bl rt_hw_trap_resv
b .
#ifdef RT_USING_SMP
.global set_secondary_cpu_boot_address
set_secondary_cpu_boot_address:
ldr r0, =secondary_cpu_start
mvn r1, #0 //0xffffffff
ldr r2, =0x10000034
str r1, [r2]
str r0, [r2, #-4]
mov pc, lr
.global secondary_cpu_start
secondary_cpu_start:
mrc p15, 0, r1, c1, c0, 1
mov r0, #(1<<6)
orr r1, r0
mcr p15, 0, r1, c1, c0, 1 //enable smp
mrc p15, 0, r0, c1, c0, 0
bic r0, #(1<<13)
mcr p15, 0, r0, c1, c0, 0
cps #Mode_IRQ
ldr sp, =irq_stack_2_limit
cps #Mode_FIQ
ldr sp, =irq_stack_2_limit
cps #Mode_SVC
ldr sp, =svc_stack_2_limit
/* initialize the mmu table and enable mmu */
bl rt_hw_mmu_init
b secondary_cpu_c_start
#endif
.bss
.align 2 //align to 2~2=4
svc_stack_2:
.space (1 << 10)
svc_stack_2_limit:
irq_stack_2:
.space (1 << 10)
irq_stack_2_limit:
|
