# mod.rs - source
Source of the Rust file `/home/justine/.cargo/registry/src/github.com-1ecc6299db9ec823/rustix-0.36.6/src/backend/linux_raw/arch/mod.rs`.
Keywords: rust, rustlang, rust-lang

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    //! Architecture-specific syscall code.
    //!
    //! `rustix` has inline assembly sequences using `asm!`, but that requires
    //! nightly Rust, so it also has out-of-line ("outline") assembly sequences
    //! in .s files. And 32-bit x86 is special (see comments below).
    //!
    //! This module also has a `choose` submodule which chooses a scheme and is
    //! what most of the `rustix` syscalls use.
    //!
    //! # Safety
    //!
    //! This contains the inline `asm` statements performing the syscall
    //! instructions and FFI declarations declaring the out-of-line ("outline")
    //! syscall instructions.

    #![allow(unsafe_code)]
    #![cfg_attr(not(feature = "all-apis"), allow(unused_imports))]
    // We'll use as many arguments as syscalls need.
    #![allow(clippy::too_many_arguments)]

    // When inline asm is available, use it. Otherwise, use out-of-line asm. These
    // functions always use the machine's syscall instruction, even when it isn't
    // the fastest option available.
    #[cfg_attr(asm, path = "inline/mod.rs")]
    #[cfg_attr(not(asm), path = "outline/mod.rs")]
    pub(in crate::backend) mod asm;

    // On most architectures, the architecture syscall instruction is fast, so use
    // it directly.
    #[cfg(any(
        target_arch = "arm",
        target_arch = "aarch64",
        target_arch = "mips",
        target_arch = "mips64",
        target_arch = "powerpc64",
        target_arch = "riscv64",
        target_arch = "x86_64",
    ))]
    pub(in crate::backend) use self::asm as choose;

    // On 32-bit x86, use vDSO wrappers for all syscalls. We could use the
    // architecture syscall instruction (`int 0x80`), but the vDSO kernel_vsyscall
    // mechanism is much faster.
    #[cfg(target_arch = "x86")]
    pub(in crate::backend) use super::vdso_wrappers::x86_via_vdso as choose;

    // This would be the code for always using `int 0x80` on 32-bit x86.
    //#[cfg(target_arch = "x86")]
    //pub(in crate::backend) use self::asm as choose;

    // Macros for invoking system calls.
    //
    // These factor out:
    //  - Calling `nr` on the syscall number to convert it into `SyscallNumber`.
    //  - Calling `.into()` on each of the arguments to convert them into `ArgReg`.
    //  - Qualifying the `syscall*` and `__NR_*` identifiers.
    //  - Counting the number of arguments.
    macro_rules! syscall {
        ($nr:ident) => {
            $crate::backend::arch::choose::syscall0($crate::backend::reg::nr(
                linux_raw_sys::general::$nr,
            ))
        };

        ($nr:ident, $a0:expr) => {
            $crate::backend::arch::choose::syscall1(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr) => {
            $crate::backend::arch::choose::syscall2(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr) => {
            $crate::backend::arch::choose::syscall3(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr, $a3:expr) => {
            $crate::backend::arch::choose::syscall4(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
                $a3.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr, $a3:expr, $a4:expr) => {
            $crate::backend::arch::choose::syscall5(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
                $a3.into(),
                $a4.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr) => {
            $crate::backend::arch::choose::syscall6(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
                $a3.into(),
                $a4.into(),
                $a5.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr) => {
            $crate::backend::arch::choose::syscall7(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
                $a3.into(),
                $a4.into(),
                $a5.into(),
                $a6.into(),
            )
        };
    }

    macro_rules! syscall_readonly {
        ($nr:ident) => {
            $crate::backend::arch::choose::syscall0_readonly($crate::backend::reg::nr(
                linux_raw_sys::general::$nr,
            ))
        };

        ($nr:ident, $a0:expr) => {
            $crate::backend::arch::choose::syscall1_readonly(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr) => {
            $crate::backend::arch::choose::syscall2_readonly(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr) => {
            $crate::backend::arch::choose::syscall3_readonly(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr, $a3:expr) => {
            $crate::backend::arch::choose::syscall4_readonly(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
                $a3.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr, $a3:expr, $a4:expr) => {
            $crate::backend::arch::choose::syscall5_readonly(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
                $a3.into(),
                $a4.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr) => {
            $crate::backend::arch::choose::syscall6_readonly(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
                $a3.into(),
                $a4.into(),
                $a5.into(),
            )
        };

        ($nr:ident, $a0:expr, $a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr) => {
            $crate::backend::arch::choose::syscall7_readonly(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
                $a1.into(),
                $a2.into(),
                $a3.into(),
                $a4.into(),
                $a5.into(),
                $a6.into(),
            )
        };
    }

    #[cfg(feature = "runtime")]
    macro_rules! syscall_noreturn {
        ($nr:ident, $a0:expr) => {
            $crate::backend::arch::choose::syscall1_noreturn(
                $crate::backend::reg::nr(linux_raw_sys::general::$nr),
                $a0.into(),
            )
        };
    }