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
|
use core::{
arch::{asm, global_asm},
time::Duration,
};
use log::info;
use vernos_driver_riscv_timer::{set_timer, Instant};
/// Sets up the timer interrupt.
#[inline(never)]
pub(crate) fn example_timer() {
let now = Instant::now();
info!("now = {now:?}");
let in_a_sec = now + Duration::from_secs(1);
info!("in_a_sec = {in_a_sec:?}");
info!("setting a timer for 1s...");
set_timer(in_a_sec);
enable_interrupts();
}
/// Disables interrupts.
pub fn disable_interrupts() {
// Set SSTATUS.SIE to 0, which disables interrupts.
//
// SAFETY: Not running interrupts shouldn't be able to compromise safety.
unsafe {
asm!(
"csrc sstatus, {sie}",
sie = in(reg) (1 << 1),
options(nomem, nostack)
);
}
}
/// Enables interrupts.
pub fn enable_interrupts() {
// Set STVEC.BASE to the handler function, and STVEC.MODE to Direct. Since the trap_handler_asm
// has a `.align 4` before it, the lower two bits of its address should already be zero.
//
// SAFETY: Even if interrupts were already enabled, this is a valid handler.
unsafe {
asm!(
"csrw stvec, {stvec}",
stvec = in(reg) trap_handler_asm,
options(nomem, nostack)
);
}
// Set SSTATUS.SIE to 1, which enables interrupts.
//
// SAFETY: We just initialized STVEC, so it should be able to handle interrupts.
unsafe {
asm!(
"csrs sstatus, {sie}",
sie = in(reg) (1 << 1),
options(nomem, nostack)
);
}
}
fn trap_handler() {
todo!("trap_handler")
}
// The assembly code that calls the Rust trap handler, after saving all caller-save registers
// to the stack.
global_asm! {
// Declare the handler's symbol.
".align 4",
"trap_handler_asm:",
// TODO
"nop",
"call {trap_handler}",
trap_handler = sym trap_handler
}
extern "C" {
fn trap_handler_asm();
}
|
