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
|
// See LICENSE for license details.
#include "pk.h"
#include "config.h"
#include "syscall.h"
#include "vm.h"
static void handle_illegal_instruction(trapframe_t* tf)
{
tf->insn = *(uint16_t*)tf->epc;
int len = insn_len(tf->insn);
if (len == 4)
tf->insn |= ((uint32_t)*(uint16_t*)(tf->epc + 2) << 16);
else
kassert(len == 2);
dump_tf(tf);
panic("An illegal instruction was executed!");
}
static void handle_breakpoint(trapframe_t* tf)
{
dump_tf(tf);
printk("Breakpoint!\n");
tf->epc += 4;
}
static void handle_misaligned_fetch(trapframe_t* tf)
{
dump_tf(tf);
panic("Misaligned instruction access!");
}
void handle_misaligned_load(trapframe_t* tf)
{
// TODO emulate misaligned loads and stores
dump_tf(tf);
panic("Misaligned load!");
}
void handle_misaligned_store(trapframe_t* tf)
{
dump_tf(tf);
panic("Misaligned store!");
}
static void segfault(trapframe_t* tf, uintptr_t addr, const char* type)
{
dump_tf(tf);
const char* who = (tf->status & MSTATUS_PRV1) ? "Kernel" : "User";
panic("%s %s segfault @ %p", who, type, addr);
}
static void handle_fault_fetch(trapframe_t* tf)
{
if (handle_page_fault(tf->epc, PROT_EXEC) != 0)
segfault(tf, tf->epc, "fetch");
}
void handle_fault_load(trapframe_t* tf)
{
tf->badvaddr = read_csr(sbadaddr);
if (handle_page_fault(tf->badvaddr, PROT_READ) != 0)
segfault(tf, tf->badvaddr, "load");
}
void handle_fault_store(trapframe_t* tf)
{
tf->badvaddr = read_csr(sbadaddr);
if (handle_page_fault(tf->badvaddr, PROT_WRITE) != 0)
segfault(tf, tf->badvaddr, "store");
}
static void handle_syscall(trapframe_t* tf)
{
tf->gpr[10] = do_syscall(tf->gpr[10], tf->gpr[11], tf->gpr[12], tf->gpr[13],
tf->gpr[14], tf->gpr[15], tf->gpr[17]);
tf->epc += 4;
}
static void handle_interrupt(trapframe_t* tf)
{
clear_csr(sstatus, SSTATUS_SIP);
pop_tf(tf);
}
void handle_trap(trapframe_t* tf)
{
if ((intptr_t)tf->cause < 0)
return handle_interrupt(tf);
typedef void (*trap_handler)(trapframe_t*);
const static trap_handler trap_handlers[] = {
[CAUSE_MISALIGNED_FETCH] = handle_misaligned_fetch,
[CAUSE_FAULT_FETCH] = handle_fault_fetch,
[CAUSE_ILLEGAL_INSTRUCTION] = handle_illegal_instruction,
[CAUSE_SCALL] = handle_syscall,
[CAUSE_BREAKPOINT] = handle_breakpoint,
[CAUSE_MISALIGNED_LOAD] = handle_misaligned_load,
[CAUSE_MISALIGNED_STORE] = handle_misaligned_store,
[CAUSE_FAULT_LOAD] = handle_fault_load,
[CAUSE_FAULT_STORE] = handle_fault_store,
};
kassert(tf->cause < ARRAY_SIZE(trap_handlers) && trap_handlers[tf->cause]);
trap_handlers[tf->cause](tf);
pop_tf(tf);
}
|
