rCore-OS: 基本执行环境

 1$ rustc --print target-list | grep riscv
 2riscv32gc-unknown-linux-gnu
 3riscv32gc-unknown-linux-musl
 4riscv32i-unknown-none-elf
 5riscv32im-unknown-none-elf
 6riscv32imac-esp-espidf
 7riscv32imac-unknown-none-elf
 8riscv32imac-unknown-xous-elf
 9riscv32imc-esp-espidf
10riscv32imc-unknown-none-elf
11riscv64gc-unknown-freebsd
12riscv64gc-unknown-fuchsia
13riscv64gc-unknown-linux-gnu
14riscv64gc-unknown-linux-musl
15riscv64gc-unknown-none-elf
16riscv64gc-unknown-openbsd
17riscv64imac-unknown-none-elf

 1$ cargo build
 2   Compiling os v0.1.0 (/home/rqdmap/tmp/os)
 3error[E0463]: can't find crate for `std`
 4  |
 5  = note: the `riscv64gc-unknown-none-elf` target may not support the standard library
 6  = note: `std` is required by `os` because it does not declare `#![no_std]`
 7  = help: consider building the standard library from source with `cargo build -Zbuild-std`
 8
 9error: cannot find macro `println` in this scope
10 --> src/main.rs:2:5
11  |
122 |     println!("Hello, world!");
13  |     ^^^^^^^
14
15error: `#[panic_handler]` function required, but not found
16
17For more information about this error, try `rustc --explain E0463`.
18error: could not compile `os` (bin "os") due to 3 previous errors

 1OUTPUT_ARCH(riscv)
 2ENTRY(_start)
 3BASE_ADDRESS = 0x80200000;
 4
 5SECTIONS
 6{
 7    . = BASE_ADDRESS;
 8    skernel = .;
 9
10    stext = .;
11    .text : {
12        *(.text.entry)
13        *(.text .text.*)
14    }
15
16    . = ALIGN(4K);
17    etext = .;
18    srodata = .;
19    .rodata : {
20        *(.rodata .rodata.*)
21        *(.srodata .srodata.*)
22    }
23
24    . = ALIGN(4K);
25    erodata = .;
26    sdata = .;
27    .data : {
28        *(.data .data.*)
29        *(.sdata .sdata.*)
30    }
31
32    . = ALIGN(4K);
33    edata = .;
34    .bss : {
35        *(.bss.stack)
36        sbss = .;
37        *(.bss .bss.*)
38        *(.sbss .sbss.*)
39    }
40
41    . = ALIGN(4K);
42    ebss = .;
43    ekernel = .;
44
45    /DISCARD/ : {
46        *(.eh_frame)
47    }
48}

 1$ readelf -a target/riscv64gc-unknown-none-elf/debug/os
 2...
 3Section Headers:
 4  [Nr] Name              Type             Address           Offset
 5       Size              EntSize          Flags  Link  Info  Align
 6  [ 0]                   NULL             0000000000000000  00000000
 7       0000000000000000  0000000000000000           0     0     0
 8  [ 1] .text             PROGBITS         0000000080200000  00001000
 9       0000000000000004  0000000000000000  AX       0     0     1
10  [ 2] .bss              NOBITS           0000000080201000  00001004
11       0000000000000000  0000000000000000  WA       0     0     1
12...
13Symbol table '.symtab' contains 106 entries:
14   Num:    Value          Size Type    Bind   Vis      Ndx Name
15   ...
16    92: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT   10
17    93: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS yqvkc8kq9bldvip
18    94: 0000000080200000     0 NOTYPE  GLOBAL DEFAULT    1 _start
19    95: 0000000080200000     0 NOTYPE  GLOBAL DEFAULT  ABS BASE_ADDRESS
20    96: 0000000080200000     0 NOTYPE  GLOBAL DEFAULT    1 skernel
21    97: 0000000080200000     0 NOTYPE  GLOBAL DEFAULT    1 stext
22    98: 0000000080201000     0 NOTYPE  GLOBAL DEFAULT    1 etext
23    99: 0000000080201000     0 NOTYPE  GLOBAL DEFAULT    1 srodata
24   100: 0000000080201000     0 NOTYPE  GLOBAL DEFAULT    1 erodata
25   101: 0000000080201000     0 NOTYPE  GLOBAL DEFAULT    1 sdata
26   102: 0000000080201000     0 NOTYPE  GLOBAL DEFAULT    1 edata
27   103: 0000000080201000     0 NOTYPE  GLOBAL DEFAULT    2 sbss
28   104: 0000000080201000     0 NOTYPE  GLOBAL DEFAULT    2 ebss
29   105: 0000000080201000     0 NOTYPE  GLOBAL DEFAULT    2 ekernel

 1$ rust-objcopy --strip-all target/riscv64gc-unknown-none-elf/release/os -O binary target/riscv64gc-unknown-none-elf/release/os.bin
 2
 3$ stat os
 4  File: os
 5  Size: 5208      	Blocks: 16         IO Block: 4096   regular file
 6Device: 0,42	Inode: 17893504    Links: 2
 7Access: (0755/-rwxr-xr-x)  Uid: ( 1000/  rqdmap)   Gid: ( 1000/  rqdmap)
 8Access: 2023-07-23 21:50:09.194861817 +0800
 9Modify: 2023-07-23 21:50:08.071531321 +0800
10Change: 2023-07-23 21:50:08.078197971 +0800
11 Birth: 2023-07-23 21:50:08.071531321 +0800
12
13$ stat os.bin
14  File: os.bin
15  Size: 4         	Blocks: 8          IO Block: 4096   regular file
16Device: 0,42	Inode: 17893509    Links: 1
17Access: (0755/-rwxr-xr-x)  Uid: ( 1000/  rqdmap)   Gid: ( 1000/  rqdmap)
18Access: 2023-07-23 21:50:09.194861817 +0800
19Modify: 2023-07-23 21:50:09.198195141 +0800
20Change: 2023-07-23 21:50:09.198195141 +0800
21 Birth: 2023-07-23 21:50:09.194861817 +0800

 1// sbi.rs
 2#![allow(unused)] // 此行请放在该文件最开头
 3const SBI_SET_TIMER: usize = 0;
 4const SBI_CONSOLE_PUTCHAR: usize = 1;
 5const SBI_CONSOLE_GETCHAR: usize = 2;
 6const SBI_CLEAR_IPI: usize = 3;
 7const SBI_SEND_IPI: usize = 4;
 8const SBI_REMOTE_FENCE_I: usize = 5;
 9const SBI_REMOTE_SFENCE_VMA: usize = 6;
10const SBI_REMOTE_SFENCE_VMA_ASID: usize = 7;
11const SBI_SHUTDOWN: usize = 8;
12
13use core::arch::asm;
14#[inline(always)]
15fn sbi_call(which: usize, arg0: usize, arg1: usize, arg2: usize) -> usize {
16    let mut ret;
17    unsafe {
18        asm!(
19            "ecall",
20            inlateout("x10") arg0 => ret,
21            in("x11") arg1,
22            in("x12") arg2,
23            in("x17") which,
24        );
25    }
26    ret
27}
28
29pub fn console_putchar(c: usize) {
30    sbi_call(SBI_CONSOLE_PUTCHAR, c, 0, 0);
31}
32
33pub fn shutdown() -> ! {
34    sbi_call(SBI_SHUTDOWN, 0, 0, 0);
35    panic!("It should shutdown!");
36}

 1// os/src/lang_item.rs
 2use crate::sbi::shutdown;
 3use core::panic::PanicInfo;
 4
 5#[panic_handler]
 6fn panic(info: &PanicInfo) -> ! {
 7    if let Some(location) = info.location() {
 8        println!(
 9            "Panicked at {}:{} {}",
10            location.file(),
11            location.line(),
12            info.message().unwrap()
13        );
14    } else {
15        println!("Panicked: {}", info.message().unwrap());
16    }
17    shutdown()
18}

 1// src/logging.rs
 2pub fn init() {
 3    static LOGGER: SimpleLogger = SimpleLogger;
 4    log::set_logger(&LOGGER).unwrap();
 5    log::set_max_level(match option_env!("LOG") {
 6        Some("ERROR") => LevelFilter::Error,
 7        Some("WARN") => LevelFilter::Warn,
 8        Some("INFO") => LevelFilter::Info,
 9        Some("DEBUG") => LevelFilter::Debug,
10        Some("TRACE") => LevelFilter::Trace,
11        _ => LevelFilter::Off,
12    });
13}
14
15// **/core/src/macros/mod.rs
16#[stable(feature = "rust1", since = "1.0.0")]
17#[rustc_builtin_macro]
18#[macro_export]
19#[cfg_attr(not(test), rustc_diagnostic_item = "option_env_macro")]
20macro_rules! option_env {
21($name:expr $(,)?) => {{ /* compiler built-in */ }};
22}