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
|
# See LICENSE for license details.
.include "macros.s"
.include "constants.s"
#
# start of trap handler
#
.section .text.init,"ax",@progbits
.globl _start
_start:
# setup default trap vector
la t0, trap_vector
csrw mtvec, t0
# set up stack pointer based on hartid
csrr t0, mhartid
slli t0, t0, STACK_SHIFT
la sp, stacks + STACK_SIZE
add sp, sp, t0
# park all harts excpet hart 0
csrr a0, mhartid
bnez a0, park
# jump to libfemto_start_main
j libfemto_start_main
# sleeping harts mtvec calls trap_fn upon receiving IPI
park:
wfi
j park
.align 2
trap_vector:
# Save registers.
addi sp, sp, -CONTEXT_SIZE
sxsp ra, 0
sxsp a0, 1
sxsp a1, 2
sxsp a2, 3
sxsp a3, 4
sxsp a4, 5
sxsp a5, 6
sxsp a6, 7
sxsp a7, 8
sxsp t0, 9
sxsp t1, 10
sxsp t2, 11
sxsp t3, 12
sxsp t4, 13
sxsp t5, 14
sxsp t6, 15
# Invoke the handler.
mv a0, sp
csrr a1, mcause
csrr a2, mepc
jal trap_handler
# Restore registers.
lxsp ra, 0
lxsp a0, 1
lxsp a1, 2
lxsp a2, 3
lxsp a3, 4
lxsp a4, 5
lxsp a5, 6
lxsp a6, 7
lxsp a7, 8
lxsp t0, 9
lxsp t1, 10
lxsp t2, 11
lxsp t3, 12
lxsp t4, 13
lxsp t5, 14
lxsp t6, 15
addi sp, sp, CONTEXT_SIZE
# Return
mret
.bss
.align 4
.global stacks
stacks:
.skip STACK_SIZE * MAX_HARTS
|
