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refactor: ByteOffset newtype for window/register/ring offsets; named virtio-gpu cmd fields

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This commit is contained in:
Gabriel Kaszewski
2026-10-27 21:52:33 +01:00
parent 842d14987c
commit 7b8258b231
13 changed files with 145 additions and 93 deletions
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2
crates/apps/smptest/src/main.rs
View File

@@ -23,7 +23,7 @@ fn main() {
libkos::println!("smptest: cannot map the counter page");
syscall::exit();
};
let words = window.atomics(0, 1 + THREADS);
let words = window.atomics(types::address::ByteOffset::ZERO, 1 + THREADS);
for _ in 1..THREADS {
if !libkos::thread::spawn(words, spin) {
break;

8
crates/drivers/block/virtio/src/lib.rs
View File

@@ -5,7 +5,7 @@ use hw_virtio::block::{self, DmaAddrs};
use hw_virtio::mmio::{MmioAccess, Registers};
use hw_virtio::queue::VirtioQueue;
use port_block_device::{BlockDevice, SectorId};
use types::address::{PhysicalAddress, VirtualAddress};
use types::address::{ByteOffset, PhysicalAddress, VirtualAddress};
use types::bounded::PageCount;
const MMIO_VA: VirtualAddress = VirtualAddress::from_raw(0x20000);
@@ -38,11 +38,11 @@ impl VirtioBlockDevice {
let at = |offset: usize| PhysicalAddress::from_raw(req.physical.raw() + offset);
let dma = DmaAddrs {
header_pa: at(0),
header: req.window.sub(0, 16),
header: req.window.sub(ByteOffset::new(0), 16),
status_pa: at(16),
status: req.window.sub(16, 1),
status: req.window.sub(ByteOffset::new(16), 1),
data_pa: at(32),
data: req.window.sub(32, SECTOR_SIZE),
data: req.window.sub(ByteOffset::new(32), SECTOR_SIZE),
};
let capacity = regs.read(block::CONFIG_CAPACITY) as u64
| (regs.read(block::CONFIG_CAPACITY + 4) as u64) << 32;

8
crates/drivers/framebuffer/virtio/src/lib.rs
View File

@@ -6,7 +6,7 @@ use hw_virtio::mmio::{MmioAccess, Registers};
use hw_virtio::queue::VirtioQueue;
use libkos::Window;
use port_framebuffer::Framebuffer;
use types::address::{PhysicalAddress, VirtualAddress};
use types::address::{ByteOffset, PhysicalAddress, VirtualAddress};
use types::bounded::PageCount;
use types::display::{Color, Dimension, ScreenCoord};
@@ -50,7 +50,7 @@ impl VirtioFramebuffer {
let dma = GpuDmaAddrs {
cmd_pa: cmd.physical,
cmd: cmd.window,
resp_pa: PhysicalAddress::from_raw(cmd.physical.raw() + gpu::RESPONSE),
resp_pa: PhysicalAddress::from_raw(cmd.physical.raw() + gpu::RESPONSE.raw()),
};
let (w, h) = gpu::get_display_info(&regs, &queue, &dma)
.and_then(|(w, h)| Some((u16::try_from(w).ok()?, u16::try_from(h).ok()?)))
@@ -93,7 +93,7 @@ impl Framebuffer for VirtioFramebuffer {
return;
}
let offset = (y.raw() as usize) * self.stride + (x.raw() as usize) * FB_BPP;
self.pixels.write(offset, color.raw());
self.pixels.write(ByteOffset::new(offset), color.raw());
}
fn fill_rect(&mut self, x: ScreenCoord, y: ScreenCoord, w: Dimension, h: Dimension, color: Color) {
@@ -106,7 +106,7 @@ impl Framebuffer for VirtioFramebuffer {
fn clear(&mut self, color: Color) {
let total = self.width.raw() as usize * self.height.raw() as usize;
self.pixels.fill_u32(0, total, color.raw());
self.pixels.fill_u32(ByteOffset::ZERO, total, color.raw());
}
fn flush(&mut self) {

9
crates/drivers/input/uart/src/lib.rs
View File

@@ -3,11 +3,12 @@
use libkos::Window;
use port_input_device::{InputDevice, InputEvent, Key};
use types::address::VirtualAddress;
use types::address::{ByteOffset, VirtualAddress};
const UART_VA: VirtualAddress = VirtualAddress::from_raw(0x20000);
const UART_IER_OFFSET: usize = 1;
const UART_LSR_OFFSET: usize = 5;
const UART_RBR: ByteOffset = ByteOffset::new(0);
const UART_IER_OFFSET: ByteOffset = ByteOffset::new(1);
const UART_LSR_OFFSET: ByteOffset = ByteOffset::new(5);
/// IER bit: interrupt when a received byte is waiting (cleared by reading
/// it, so `acknowledge` has nothing to do).
const IER_RX_READY: u8 = 1;
@@ -27,7 +28,7 @@ impl UartInputDevice {
}
fn read_byte(&self) -> Option<u8> {
self.has_event().then(|| self.regs.read(0))
self.has_event().then(|| self.regs.read(UART_RBR))
}
fn byte_to_key(byte: u8) -> Key {

10
crates/drivers/input/virtio/src/lib.rs
View File

@@ -7,7 +7,7 @@ use core::sync::atomic::{Ordering, fence};
use hw_virtio::mmio::{MmioAccess, Registers};
use libkos::Window;
use port_input_device::{InputDevice, InputEvent};
use types::address::{PhysicalAddress, VirtualAddress};
use types::address::{ByteOffset, PhysicalAddress, VirtualAddress};
use types::bounded::PageCount;
const INPUT_MMIO_VA: VirtualAddress = VirtualAddress::from_raw(0x25000);
@@ -18,8 +18,8 @@ const QUEUE_SIZE: usize = 32;
const EVENT_SIZE: usize = 8;
const DESC_SIZE: usize = 16;
/// Where the legacy layout puts the available and used rings.
const AVAIL: usize = QUEUE_SIZE * DESC_SIZE;
const USED: usize = 4096;
const AVAIL: ByteOffset = ByteOffset::new(QUEUE_SIZE * DESC_SIZE);
const USED: ByteOffset = ByteOffset::new(4096);
const EV_KEY: u16 = 1;
const KEY_PRESS: u32 = 1;
@@ -67,7 +67,7 @@ impl VirtioInputDevice {
/// Every buffer goes to the device, one event each.
fn fill_queue(&mut self) {
for i in 0..QUEUE_SIZE {
let desc = i * DESC_SIZE;
let desc = ByteOffset::new(i * DESC_SIZE);
self.rings.write(desc, (self.events_pa.raw() + i * EVENT_SIZE) as u64);
self.rings.write(desc + 8, EVENT_SIZE as u32);
self.rings.write(desc + 12, 2u16); // WRITE flag
@@ -92,7 +92,7 @@ impl VirtioInputDevice {
}
fn read_event(&self, desc_idx: u16) -> (u16, u16, u32) {
let at = desc_idx as usize % QUEUE_SIZE * EVENT_SIZE;
let at = ByteOffset::new(desc_idx as usize % QUEUE_SIZE * EVENT_SIZE);
(self.events.read(at), self.events.read(at + 2), self.events.read(at + 4))
}

24
crates/hw-virtio/src/block.rs
View File

@@ -1,7 +1,7 @@
use crate::mmio::MmioAccess;
use crate::queue::{Descriptor, VirtioQueue};
use libkos::Window;
use types::address::PhysicalAddress;
use types::address::{ByteOffset, PhysicalAddress};
const SECTOR_SIZE: usize = 512;
@@ -16,11 +16,15 @@ pub struct DmaAddrs {
pub data: Window,
}
const HEADER_TYPE: ByteOffset = ByteOffset::new(0);
const HEADER_RESERVED: ByteOffset = ByteOffset::new(4);
const HEADER_SECTOR: ByteOffset = ByteOffset::new(8);
fn put_header(dma: &DmaAddrs, req_type: u32, sector: u32) {
dma.header.write(0, req_type);
dma.header.write(4, 0u32);
dma.header.write(8, sector as u64);
dma.status.write(0, 0xFFu8);
dma.header.write(HEADER_TYPE, req_type);
dma.header.write(HEADER_RESERVED, 0u32);
dma.header.write(HEADER_SECTOR, sector as u64);
dma.status.write(ByteOffset::ZERO, 0xFFu8);
}
pub fn read_sector(
@@ -42,15 +46,15 @@ pub fn read_sector(
if !queue.submit(mmio, &descs) { return false; }
if dma.status.read::<u8>(0) != 0 { return false; }
dma.data.copy_to(0, &mut buf[..SECTOR_SIZE]);
if dma.status.read::<u8>(ByteOffset::ZERO) != 0 { return false; }
dma.data.copy_to(ByteOffset::ZERO, &mut buf[..SECTOR_SIZE]);
true
}
/// Request types (virtio spec 5.2.6).
const T_OUT: u32 = 1;
/// Device configuration: the disk's size in 512-byte sectors (le64).
pub const CONFIG_CAPACITY: usize = 0x100;
pub const CONFIG_CAPACITY: ByteOffset = ByteOffset::new(0x100);
/// Writes one sector from `buf`; true once the device reports success.
pub fn write_sector(
@@ -62,7 +66,7 @@ pub fn write_sector(
) -> bool {
if buf.len() < SECTOR_SIZE { return false; }
dma.data.copy_from(0, &buf[..SECTOR_SIZE]);
dma.data.copy_from(ByteOffset::ZERO, &buf[..SECTOR_SIZE]);
put_header(dma, T_OUT, sector);
// The device reads the data this time; only the status is written back.
@@ -72,5 +76,5 @@ pub fn write_sector(
Descriptor { addr: dma.status_pa.raw() as u64, len: 1, writable: true },
];
if !queue.submit(mmio, &descs) { return false; }
dma.status.read::<u8>(0) == 0
dma.status.read::<u8>(ByteOffset::ZERO) == 0
}

75
crates/hw-virtio/src/gpu.rs
View File

@@ -1,7 +1,7 @@
use crate::mmio::MmioAccess;
use crate::queue::{Descriptor, VirtioQueue};
use libkos::Window;
use types::address::PhysicalAddress;
use types::address::{ByteOffset, PhysicalAddress};
use types::display::Dimension;
/// The command page: commands go out from its start, responses come back
@@ -12,59 +12,76 @@ pub struct GpuDmaAddrs {
pub resp_pa: PhysicalAddress,
}
pub const RESPONSE: usize = 512;
pub const RESPONSE: ByteOffset = ByteOffset::new(512);
/// Command fields (virtio spec 5.7.6.7): a 24-byte header, then the body.
const TYPE: ByteOffset = ByteOffset::new(0);
const BODY: ByteOffset = ByteOffset::new(24);
/// Most bodies start with a rectangle: x, y, width, height.
const RECT_X: ByteOffset = ByteOffset::new(24);
const RECT_Y: ByteOffset = ByteOffset::new(28);
const RECT_W: ByteOffset = ByteOffset::new(32);
const RECT_H: ByteOffset = ByteOffset::new(36);
/// The 24 bytes of header and 16 of rectangle in a display-info response.
const DISPLAY_W: ByteOffset = ByteOffset::new(24 + 8);
const DISPLAY_H: ByteOffset = ByteOffset::new(24 + 12);
pub fn create_2d(mmio: &impl MmioAccess, queue: &VirtioQueue, dma: &GpuDmaAddrs, resource_id: u32, width: Dimension, height: Dimension) -> bool {
write_cmd_header(&dma.cmd, 0x0101);
dma.cmd.write(24, resource_id);
dma.cmd.write(28, 1u32);
dma.cmd.write(32, width.raw() as u32);
dma.cmd.write(36, height.raw() as u32);
// Resource id, format (1: B8G8R8A8), width, height.
dma.cmd.write(BODY, resource_id);
dma.cmd.write(BODY + 4, 1u32);
dma.cmd.write(BODY + 8, width.raw() as u32);
dma.cmd.write(BODY + 12, height.raw() as u32);
submit_cmd(mmio, queue, dma, 40)
}
pub fn attach_backing(mmio: &impl MmioAccess, queue: &VirtioQueue, dma: &GpuDmaAddrs, resource_id: u32, fb_pa: PhysicalAddress, fb_size: u32) -> bool {
write_cmd_header(&dma.cmd, 0x0106);
dma.cmd.write(24, resource_id);
dma.cmd.write(28, 1u32);
dma.cmd.write(32, fb_pa.raw() as u64 as u64);
dma.cmd.write(40, fb_size);
// Resource id, one memory entry: its address and length.
dma.cmd.write(BODY, resource_id);
dma.cmd.write(BODY + 4, 1u32);
dma.cmd.write(BODY + 8, fb_pa.raw() as u64);
dma.cmd.write(BODY + 16, fb_size);
submit_cmd(mmio, queue, dma, 48)
}
pub fn set_scanout(mmio: &impl MmioAccess, queue: &VirtioQueue, dma: &GpuDmaAddrs, scanout_id: u32, resource_id: u32, width: Dimension, height: Dimension) -> bool {
write_cmd_header(&dma.cmd, 0x0103);
dma.cmd.write(32, width.raw() as u32);
dma.cmd.write(36, height.raw() as u32);
dma.cmd.write(40, scanout_id);
dma.cmd.write(44, resource_id);
// The rectangle (from 0, 0), then scanout and resource ids.
dma.cmd.write(RECT_W, width.raw() as u32);
dma.cmd.write(RECT_H, height.raw() as u32);
dma.cmd.write(BODY + 16, scanout_id);
dma.cmd.write(BODY + 20, resource_id);
submit_cmd(mmio, queue, dma, 48)
}
pub fn transfer_to_host(mmio: &impl MmioAccess, queue: &VirtioQueue, dma: &GpuDmaAddrs, resource_id: u32, x: u32, y: u32, w: u32, h: u32) -> bool {
write_cmd_header(&dma.cmd, 0x0105);
dma.cmd.write(24, x);
dma.cmd.write(28, y);
dma.cmd.write(32, w);
dma.cmd.write(36, h);
dma.cmd.write(40, 0u64);
dma.cmd.write(48, resource_id);
put_rect(&dma.cmd, x, y, w, h);
// Offset into the resource's memory, then the resource id.
dma.cmd.write(BODY + 16, 0u64);
dma.cmd.write(BODY + 24, resource_id);
submit_cmd(mmio, queue, dma, 56)
}
pub fn resource_flush(mmio: &impl MmioAccess, queue: &VirtioQueue, dma: &GpuDmaAddrs, resource_id: u32, x: u32, y: u32, w: u32, h: u32) -> bool {
write_cmd_header(&dma.cmd, 0x0104);
dma.cmd.write(24, x);
dma.cmd.write(28, y);
dma.cmd.write(32, w);
dma.cmd.write(36, h);
dma.cmd.write(40, resource_id);
put_rect(&dma.cmd, x, y, w, h);
dma.cmd.write(BODY + 16, resource_id);
submit_cmd(mmio, queue, dma, 48)
}
fn write_cmd_header(cmd: &Window, cmd_type: u32) {
cmd.fill_u32(0, 128, 0);
cmd.write(0, cmd_type);
cmd.fill_u32(ByteOffset::ZERO, 128, 0);
cmd.write(TYPE, cmd_type);
}
fn put_rect(cmd: &Window, x: u32, y: u32, w: u32, h: u32) {
cmd.write(RECT_X, x);
cmd.write(RECT_Y, y);
cmd.write(RECT_W, w);
cmd.write(RECT_H, h);
}
pub fn get_display_info(mmio: &impl MmioAccess, queue: &VirtioQueue, dma: &GpuDmaAddrs) -> Option<(u32, u32)> {
@@ -75,8 +92,8 @@ pub fn get_display_info(mmio: &impl MmioAccess, queue: &VirtioQueue, dma: &GpuDm
];
if !queue.submit(mmio, &descs) { return None; }
if dma.cmd.read::<u32>(RESPONSE) != 0x1101 { return None; }
let w: u32 = dma.cmd.read(RESPONSE + 24 + 8);
let h: u32 = dma.cmd.read(RESPONSE + 24 + 12);
let w: u32 = dma.cmd.read(RESPONSE + DISPLAY_W.raw());
let h: u32 = dma.cmd.read(RESPONSE + DISPLAY_H.raw());
if w > 0 && h > 0 { Some((w, h)) } else { None }
}

42
crates/hw-virtio/src/mmio.rs
View File

@@ -1,26 +1,28 @@
use types::address::ByteOffset;
pub trait MmioAccess {
fn read(&self, offset: usize) -> u32;
fn write(&self, offset: usize, val: u32);
fn read(&self, offset: ByteOffset) -> u32;
fn write(&self, offset: ByteOffset, val: u32);
}
pub const MAGIC: u32 = 0x74726976;
pub const REG_MAGIC: usize = 0x000;
pub const REG_VERSION: usize = 0x004;
pub const REG_DEVICE_ID: usize = 0x008;
pub const REG_STATUS: usize = 0x070;
pub const REG_GUEST_PAGE_SIZE: usize = 0x028;
pub const REG_FEATURES_SEL: usize = 0x014;
pub const REG_FEATURES: usize = 0x010;
pub const REG_DRIVER_FEATURES_SEL: usize = 0x024;
pub const REG_DRIVER_FEATURES: usize = 0x020;
pub const REG_QUEUE_SEL: usize = 0x030;
pub const REG_QUEUE_NUM_MAX: usize = 0x034;
pub const REG_QUEUE_NUM: usize = 0x038;
pub const REG_QUEUE_PFN: usize = 0x040;
pub const REG_QUEUE_NOTIFY: usize = 0x050;
pub const REG_INTERRUPT_STATUS: usize = 0x060;
pub const REG_INTERRUPT_ACK: usize = 0x064;
pub const REG_MAGIC: ByteOffset = ByteOffset::new(0x000);
pub const REG_VERSION: ByteOffset = ByteOffset::new(0x004);
pub const REG_DEVICE_ID: ByteOffset = ByteOffset::new(0x008);
pub const REG_STATUS: ByteOffset = ByteOffset::new(0x070);
pub const REG_GUEST_PAGE_SIZE: ByteOffset = ByteOffset::new(0x028);
pub const REG_FEATURES_SEL: ByteOffset = ByteOffset::new(0x014);
pub const REG_FEATURES: ByteOffset = ByteOffset::new(0x010);
pub const REG_DRIVER_FEATURES_SEL: ByteOffset = ByteOffset::new(0x024);
pub const REG_DRIVER_FEATURES: ByteOffset = ByteOffset::new(0x020);
pub const REG_QUEUE_SEL: ByteOffset = ByteOffset::new(0x030);
pub const REG_QUEUE_NUM_MAX: ByteOffset = ByteOffset::new(0x034);
pub const REG_QUEUE_NUM: ByteOffset = ByteOffset::new(0x038);
pub const REG_QUEUE_PFN: ByteOffset = ByteOffset::new(0x040);
pub const REG_QUEUE_NOTIFY: ByteOffset = ByteOffset::new(0x050);
pub const REG_INTERRUPT_STATUS: ByteOffset = ByteOffset::new(0x060);
pub const REG_INTERRUPT_ACK: ByteOffset = ByteOffset::new(0x064);
pub const STATUS_ACK: u32 = 1;
pub const STATUS_DRIVER: u32 = 2;
@@ -42,11 +44,11 @@ impl Registers {
}
impl MmioAccess for Registers {
fn read(&self, offset: usize) -> u32 {
fn read(&self, offset: ByteOffset) -> u32 {
self.0.read(offset)
}
fn write(&self, offset: usize, val: u32) {
fn write(&self, offset: ByteOffset, val: u32) {
self.0.write(offset, val)
}
}

7
crates/hw-virtio/src/queue.rs
View File

@@ -1,13 +1,14 @@
use crate::mmio::{MmioAccess, REG_QUEUE_NOTIFY};
use core::sync::atomic::{Ordering, fence};
use libkos::Window;
use types::address::ByteOffset;
pub const QUEUE_SIZE: usize = 8;
const DESC_SIZE: usize = 16;
const TIMEOUT: u32 = 10_000_000;
/// Where the legacy layout puts the available and used rings.
const AVAIL: usize = QUEUE_SIZE * DESC_SIZE;
const USED: usize = 4096;
const AVAIL: ByteOffset = ByteOffset::new(QUEUE_SIZE * DESC_SIZE);
const USED: ByteOffset = ByteOffset::new(4096);
pub struct Descriptor {
pub addr: u64,
@@ -32,7 +33,7 @@ impl VirtioQueue {
}
let r = &self.rings;
for (i, d) in descs.iter().enumerate() {
let at = i * DESC_SIZE;
let at = ByteOffset::new(i * DESC_SIZE);
let last = i == descs.len() - 1;
let flags: u16 = if d.writable { 2 } else { 0 } | if !last { 1 } else { 0 };
r.write(at, d.addr);

6
crates/init/src/load.rs
View File

@@ -2,7 +2,7 @@
use libkos::fs::Storage;
use libkos::syscall;
use types::address::{EntryPoint, VirtualAddress};
use types::address::{ByteOffset, EntryPoint, VirtualAddress};
use types::bounded::{CapSlot, PageCount};
use types::budget::Limits;
@@ -53,7 +53,7 @@ pub(crate) fn load_binary(
let page_count = PageCount::new(u16::try_from(seg_pages).ok()?)?;
let local = libkos::window::request(page_count)?;
local.fill_u32(0, seg_pages * PAGE_SIZE / 4, 0);
local.fill_u32(ByteOffset::ZERO, seg_pages * PAGE_SIZE / 4, 0);
let copy_len = segment.file_size.min(segment.mem_size);
let src = segment
@@ -61,7 +61,7 @@ pub(crate) fn load_binary(
.checked_add(copy_len)
.and_then(|end| elf_data.get(segment.file_offset..end));
if let Some(src) = src.filter(|_| copy_len > 0) {
local.copy_from(offset_in_page, src);
local.copy_from(ByteOffset::new(offset_in_page), src);
}
for p in 0..seg_pages {

2
crates/init/src/selftest.rs
View File

@@ -68,7 +68,7 @@ fn check_stopped(words: Words, what: &'static str) -> Result<(), &'static str> {
fn run_phases(storage: &mut Storage, scratch: &mut [u8]) -> Result<(), &'static str> {
let page = syscall::create_region(PageCount::new(1).ok_or("page count")?).map_err(|_| "no counter page")?;
let window = libkos::window::map(page, OBSERVE_VA, PagePerms::ReadWrite).map_err(|_| "cannot map the counter page")?;
let words = window.atomics(0, 1 + THREADS);
let words = window.atomics(types::address::ByteOffset::ZERO, 1 + THREADS);
let events = syscall::create_notification().map_err(|_| "no notification")?;
timer_is_on_time(events)?;

19
crates/libkos/src/window.rs
View File

@@ -5,7 +5,7 @@
//! Every access is volatile and bounds-checked; out of range panics.
use core::sync::atomic::AtomicUsize;
use types::address::VirtualAddress;
use types::address::{ByteOffset, VirtualAddress};
use types::bounded::{CapSlot, PageCount};
use types::mapping::PagePerms;
@@ -76,7 +76,8 @@ impl Window {
}
/// The address of `size` bytes at `offset`, aligned for them.
fn at(&self, offset: usize, size: usize, align: usize) -> usize {
fn at(&self, offset: ByteOffset, size: usize, align: usize) -> usize {
let offset = offset.raw();
let end = offset.checked_add(size);
assert!(end.is_some_and(|e| e <= self.len), "window access out of range");
let addr = self.base.raw() + offset;
@@ -84,33 +85,33 @@ impl Window {
addr
}
pub fn read<T: Scalar>(&self, offset: usize) -> T {
pub fn read<T: Scalar>(&self, offset: ByteOffset) -> T {
let addr = self.at(offset, size_of::<T>(), align_of::<T>());
// SAFETY: in range of memory mapped for this process, aligned for
// T; T is a plain integer, valid for any bits.
unsafe { core::ptr::read_volatile(addr as *const T) }
}
pub fn write<T: Scalar>(&self, offset: usize, value: T) {
pub fn write<T: Scalar>(&self, offset: ByteOffset, value: T) {
let addr = self.at(offset, size_of::<T>(), align_of::<T>());
// SAFETY: as in `read`; the window hands out no references to it.
unsafe { core::ptr::write_volatile(addr as *mut T, value) }
}
/// The `len` bytes at `offset`, as a window of their own.
pub fn sub(&self, offset: usize, len: usize) -> Window {
pub fn sub(&self, offset: ByteOffset, len: usize) -> Window {
let base = VirtualAddress::from_raw(self.at(offset, len, 1));
Window { base, len }
}
pub fn copy_from(&self, offset: usize, src: &[u8]) {
pub fn copy_from(&self, offset: ByteOffset, src: &[u8]) {
self.at(offset, src.len(), 1);
for (i, b) in src.iter().enumerate() {
self.write(offset + i, *b);
}
}
pub fn copy_to(&self, offset: usize, dst: &mut [u8]) {
pub fn copy_to(&self, offset: ByteOffset, dst: &mut [u8]) {
self.at(offset, dst.len(), 1);
for (i, b) in dst.iter_mut().enumerate() {
*b = self.read(offset + i);
@@ -118,7 +119,7 @@ impl Window {
}
/// `count` u32s from `offset` set to `value`.
pub fn fill_u32(&self, offset: usize, count: usize, value: u32) {
pub fn fill_u32(&self, offset: ByteOffset, count: usize, value: u32) {
let bytes = count.checked_mul(4).expect("window fill too large");
self.at(offset, bytes, 4);
for i in 0..count {
@@ -128,7 +129,7 @@ impl Window {
/// `count` words from `offset` as atomics, for memory shared with
/// threads or processes that only ever touch it atomically.
pub fn atomics(&self, offset: usize, count: usize) -> &'static [AtomicUsize] {
pub fn atomics(&self, offset: ByteOffset, count: usize) -> &'static [AtomicUsize] {
let bytes = count.checked_mul(size_of::<AtomicUsize>()).expect("too many atomics");
let addr = self.at(offset, bytes, align_of::<AtomicUsize>());
// SAFETY: mapped and aligned; AtomicUsize may be shared and is

26
crates/types/src/address.rs
View File

@@ -68,3 +68,29 @@ impl DataRef {
}
}
}
/// A position in bytes inside a mapped window: a device register, a field
/// of a ring or command. Adding a byte count moves it along.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub struct ByteOffset(usize);
impl ByteOffset {
pub const ZERO: Self = Self(0);
pub const fn new(bytes: usize) -> Self {
Self(bytes)
}
pub const fn raw(&self) -> usize {
self.0
}
}
impl core::ops::Add<usize> for ByteOffset {
type Output = Self;
/// Saturates: an offset past the end is refused where it is used.
fn add(self, bytes: usize) -> Self {
Self(self.0.saturating_add(bytes))
}
}