syscalls
syscall 通过寄存器里放的数值，判断该调用哪个内核函数．不同主流架构都有自己的 syscall 方式，例如
在 Rust 中，我们可以用 unsafe { core::arch::asm!() } 手动调用汇编 syscall．
| Arch |
Instruction |
Syscall ID Reg |
Return Reg |
Argument Registers |
| x86_64 |
syscall |
rax |
rax |
rdi, rsi, rdx, r10, r8, r9 |
| aarch64 |
svc #0 |
x8 |
x0 |
x0, x1, x2, x3, x4, x5 |
| riscv64 |
ecall |
a7 |
a0 |
a0, a1, a2, a3, a4, a5 |
x86_64 调用示例1
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| pub unsafe fn syscall3(
id: usize,
arg0: usize,
arg1: usize,
arg2: usize
) -> isize {
let ret: isize;
unsafe {
core::arch::asm!(
"syscall",
inlateout("rax") id as isize => ret,
in("rdi") arg0,
in("rsi") arg1,
in("rdx") arg2,
out("rcx") _,
out("r11") _,
);
}
ret
}
|
ARM64 调用示例1
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| pub unsafe fn syscall3(
id: usize,
arg0: usize,
arg1: usize,
arg2: usize
) -> isize {
let ret: isize;
unsafe {
core::arch::asm!(
"svc #0",
in("x8") id,
inlateout("x0") arg0 as isize => ret,
in("x1") arg1,
in("x2") arg2,
);
}
ret
}
|
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