axhal/
lib.rs

1//! [ArceOS] hardware abstraction layer, provides unified APIs for
2//! platform-specific operations.
3//!
4//! It does the bootstrapping and initialization process for the specified
5//! platform, and provides useful operations on the hardware.
6//!
7//! Currently supported platforms (specify by cargo features):
8//!
9//! - `x86-pc`: Standard PC with x86_64 ISA.
10//! - `riscv64-qemu-virt`: QEMU virt machine with RISC-V ISA.
11//! - `aarch64-qemu-virt`: QEMU virt machine with AArch64 ISA.
12//! - `aarch64-raspi`: Raspberry Pi with AArch64 ISA.
13//! - `dummy`: If none of the above platform is selected, the dummy platform
14//!   will be used. In this platform, most of the operations are no-op or
15//!   `unimplemented!()`. This platform is mainly used for [cargo test].
16//!
17//! # Cargo Features
18//!
19//! - `smp`: Enable SMP (symmetric multiprocessing) support.
20//! - `fp-simd`: Enable floating-point and SIMD support.
21//! - `paging`: Enable page table manipulation.
22//! - `irq`: Enable interrupt handling support.
23//! - `tls`: Enable kernel space thread-local storage support.
24//! - `rtc`: Enable real-time clock support.
25//! - `uspace`: Enable user space support.
26//!
27//! [ArceOS]: https://github.com/arceos-org/arceos
28//! [cargo test]: https://doc.rust-lang.org/cargo/guide/tests.html
29
30#![no_std]
31#![feature(doc_auto_cfg)]
32
33#[allow(unused_imports)]
34#[macro_use]
35extern crate log;
36
37#[allow(unused_imports)]
38#[macro_use]
39extern crate axlog;
40
41#[allow(unused_imports)]
42#[macro_use]
43extern crate memory_addr;
44
45cfg_if::cfg_if! {
46    if #[cfg(feature = "myplat")] {
47        // link the custom platform crate in your application.
48    } else if #[cfg(target_os = "none")] {
49        #[cfg(target_arch = "x86_64")]
50        extern crate axplat_x86_pc;
51        #[cfg(target_arch = "aarch64")]
52        extern crate axplat_aarch64_qemu_virt;
53        #[cfg(target_arch = "riscv64")]
54        extern crate axplat_riscv64_qemu_virt;
55        #[cfg(target_arch = "loongarch64")]
56        extern crate axplat_loongarch64_qemu_virt;
57    } else {
58        // Link the dummy platform implementation to pass cargo test.
59        mod dummy;
60    }
61}
62
63pub mod mem;
64pub mod percpu;
65pub mod time;
66
67#[cfg(feature = "tls")]
68pub mod tls;
69
70#[cfg(feature = "irq")]
71pub mod irq;
72
73#[cfg(feature = "paging")]
74pub mod paging;
75
76/// Console input and output.
77pub mod console {
78    pub use axplat::console::{read_bytes, write_bytes};
79}
80
81/// CPU power management.
82pub mod power {
83    #[cfg(feature = "smp")]
84    pub use axplat::power::cpu_boot;
85    pub use axplat::power::system_off;
86}
87
88/// Trap handling.
89pub mod trap {
90    #[cfg(feature = "uspace")]
91    pub use axcpu::trap::SYSCALL;
92    pub use axcpu::trap::{IRQ, PAGE_FAULT};
93    pub use axcpu::trap::{PageFaultFlags, register_trap_handler};
94}
95
96/// CPU register states for context switching.
97///
98/// There are three types of context:
99///
100/// - [`TaskContext`][axcpu::TaskContext]: The context of a task.
101/// - [`TrapFrame`][axcpu::TrapFrame]: The context of an interrupt or an exception.
102/// - [`UspaceContext`][axcpu::uspace::UspaceContext]: The context for user/kernel mode switching.
103pub mod context {
104    #[cfg(feature = "uspace")]
105    pub use axcpu::uspace::UspaceContext;
106    pub use axcpu::{TaskContext, TrapFrame};
107}
108
109pub use axcpu::asm;
110
111#[cfg(feature = "smp")]
112pub use axplat::init::{init_early_secondary, init_later_secondary};
113#[cfg(feature = "smp")]
114use core::sync::atomic::{AtomicUsize, Ordering};
115
116/// Initializes CPU-local data structures for the primary core.
117///
118/// This function should be called as early as possible, as other initializations
119/// may acess the CPU-local data.
120pub fn init_percpu(cpu_id: usize) {
121    self::percpu::init_primary(cpu_id);
122}
123
124/// Initializes CPU-local data structures for secondary cores.
125///
126/// This function should be called as early as possible, as other initializations
127/// may acess the CPU-local data.
128#[cfg(feature = "smp")]
129pub fn init_percpu_secondary(cpu_id: usize) {
130    self::percpu::init_secondary(cpu_id);
131}
132
133/// Initializes the platform and boot argument.
134/// This function should be called as early as possible.
135pub fn init_early(cpu_id: usize, arg: usize) {
136    BOOT_ARG.init_once(arg);
137    axplat::init::init_early(cpu_id, arg);
138}
139
140/// Initializes the platform later stage.
141pub fn init_later(cpu_id: usize, arg: usize) {
142    axplat::init::init_later(cpu_id, arg);
143    init_cpu_num();
144}
145
146use lazyinit::LazyInit;
147
148static BOOT_ARG: LazyInit<usize> = LazyInit::new();
149
150/// Returns the boot argument.
151/// This is typically the device tree blob address passed from the bootloader.
152pub fn get_bootarg() -> usize {
153    *BOOT_ARG
154}
155
156/// The number of CPUs in the system. Based on the number declared by the
157/// platform crate and limited by the configured maximum CPU number.
158#[cfg(feature = "smp")]
159static CPU_NUM: AtomicUsize = AtomicUsize::new(1);
160
161/// Gets the number of CPUs running in the system.
162///
163/// When SMP is disabled, this function always returns 1.
164///
165/// When SMP is enabled, it's the smaller one between the platform-declared CPU
166/// number [`axplat::power::cpu_num`] and the configured maximum CPU number
167/// `axconfig::plat::MAX_CPU_NUM`.
168///
169/// This value is determined during the BSP initialization phase.
170pub fn cpu_num() -> usize {
171    #[cfg(feature = "smp")]
172    {
173        // The BSP will always see the correct value because `CPU_NUM` is set by
174        // itself.
175        //
176        // All APs will see the correct value because it is written with
177        // `Ordering::Release` and read with `Ordering::Acquire`, ensuring
178        // memory visibility.
179        //
180        // Acquire may result in a performance penalty, but this function is not
181        // expected to be called frequently in normal operation.
182        CPU_NUM.load(Ordering::Acquire)
183    }
184    #[cfg(not(feature = "smp"))]
185    {
186        1
187    }
188}
189
190/// Initializes the CPU number information.
191fn init_cpu_num() {
192    #[cfg(feature = "smp")]
193    {
194        let plat_cpu_num = axplat::power::cpu_num();
195        let max_cpu_num = axconfig::plat::MAX_CPU_NUM;
196        let cpu_num = plat_cpu_num.min(max_cpu_num);
197
198        info!("CPU number: max = {max_cpu_num}, platform = {plat_cpu_num}, use = {cpu_num}",);
199        ax_println!("smp = {}", cpu_num); // for test purposes
200
201        if plat_cpu_num > max_cpu_num {
202            warn!(
203                "platform declares more CPUs ({plat_cpu_num}) than configured max ({max_cpu_num}), \
204                only the first {max_cpu_num} CPUs will be used."
205            );
206        }
207
208        CPU_NUM.store(cpu_num, Ordering::Release);
209    }
210    #[cfg(not(feature = "smp"))]
211    {
212        ax_println!("smp = 1"); // for test purposes
213    }
214}
axhal/lib.rs

axhal/
lib.rs
