syscall/io/
mmio.rs

1#[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
2use core::ops::{BitAnd, BitOr, Not};
3use core::{mem::MaybeUninit, ptr};
4
5use super::io::Io;
6
7#[repr(transparent)]
8pub struct Mmio<T> {
9    value: MaybeUninit<T>,
10}
11
12impl<T> Mmio<T> {
13    pub unsafe fn zeroed() -> Self {
14        Self {
15            value: MaybeUninit::zeroed(),
16        }
17    }
18    pub unsafe fn uninit() -> Self {
19        Self {
20            value: MaybeUninit::uninit(),
21        }
22    }
23    pub const fn from(value: T) -> Self {
24        Self {
25            value: MaybeUninit::new(value),
26        }
27    }
28}
29
30// Generic implementation (WARNING: requires aligned pointers!)
31#[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))]
32impl<T> Io for Mmio<T>
33where
34    T: Copy + PartialEq + BitAnd<Output = T> + BitOr<Output = T> + Not<Output = T>,
35{
36    type Value = T;
37
38    fn read(&self) -> T {
39        unsafe { ptr::read_volatile(ptr::addr_of!(self.value).cast::<T>()) }
40    }
41
42    fn write(&mut self, value: T) {
43        unsafe { ptr::write_volatile(ptr::addr_of_mut!(self.value).cast::<T>(), value) };
44    }
45}
46
47// x86 u8 implementation
48#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
49impl Io for Mmio<u8> {
50    type Value = u8;
51
52    fn read(&self) -> Self::Value {
53        unsafe {
54            let value: Self::Value;
55            let ptr: *const Self::Value = ptr::addr_of!(self.value).cast::<Self::Value>();
56            core::arch::asm!(
57                "mov {}, [{}]",
58                out(reg_byte) value,
59                in(reg) ptr
60            );
61            value
62        }
63    }
64
65    fn write(&mut self, value: Self::Value) {
66        unsafe {
67            let ptr: *mut Self::Value = ptr::addr_of_mut!(self.value).cast::<Self::Value>();
68            core::arch::asm!(
69                "mov [{}], {}",
70                in(reg) ptr,
71                in(reg_byte) value,
72            );
73        }
74    }
75}
76
77// x86 u16 implementation
78#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
79impl Io for Mmio<u16> {
80    type Value = u16;
81
82    fn read(&self) -> Self::Value {
83        unsafe {
84            let value: Self::Value;
85            let ptr: *const Self::Value = ptr::addr_of!(self.value).cast::<Self::Value>();
86            core::arch::asm!(
87                "mov {:x}, [{}]",
88                out(reg) value,
89                in(reg) ptr
90            );
91            value
92        }
93    }
94
95    fn write(&mut self, value: Self::Value) {
96        unsafe {
97            let ptr: *mut Self::Value = ptr::addr_of_mut!(self.value).cast::<Self::Value>();
98            core::arch::asm!(
99                "mov [{}], {:x}",
100                in(reg) ptr,
101                in(reg) value,
102            );
103        }
104    }
105}
106
107// x86 u32 implementation
108#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
109impl Io for Mmio<u32> {
110    type Value = u32;
111
112    fn read(&self) -> Self::Value {
113        unsafe {
114            let value: Self::Value;
115            let ptr: *const Self::Value = ptr::addr_of!(self.value).cast::<Self::Value>();
116            core::arch::asm!(
117                "mov {:e}, [{}]",
118                out(reg) value,
119                in(reg) ptr
120            );
121            value
122        }
123    }
124
125    fn write(&mut self, value: Self::Value) {
126        unsafe {
127            let ptr: *mut Self::Value = ptr::addr_of_mut!(self.value).cast::<Self::Value>();
128            core::arch::asm!(
129                "mov [{}], {:e}",
130                in(reg) ptr,
131                in(reg) value,
132            );
133        }
134    }
135}
136
137// x86 u64 implementation (x86_64 only)
138#[cfg(target_arch = "x86_64")]
139impl Io for Mmio<u64> {
140    type Value = u64;
141
142    fn read(&self) -> Self::Value {
143        unsafe {
144            let value: Self::Value;
145            let ptr: *const Self::Value = ptr::addr_of!(self.value).cast::<Self::Value>();
146            core::arch::asm!(
147                "mov {:r}, [{}]",
148                out(reg) value,
149                in(reg) ptr
150            );
151            value
152        }
153    }
154
155    fn write(&mut self, value: Self::Value) {
156        unsafe {
157            let ptr: *mut Self::Value = ptr::addr_of_mut!(self.value).cast::<Self::Value>();
158            core::arch::asm!(
159                "mov [{}], {:r}",
160                in(reg) ptr,
161                in(reg) value,
162            );
163        }
164    }
165}
syscall/io/mmio.rs

syscall/io/
mmio.rs
