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Diffstat (limited to 'vendor/rustix/src/backend/linux_raw/arch/x86.rs')
| -rw-r--r-- | vendor/rustix/src/backend/linux_raw/arch/x86.rs | 489 |
1 files changed, 489 insertions, 0 deletions
diff --git a/vendor/rustix/src/backend/linux_raw/arch/x86.rs b/vendor/rustix/src/backend/linux_raw/arch/x86.rs new file mode 100644 index 0000000..e789181 --- /dev/null +++ b/vendor/rustix/src/backend/linux_raw/arch/x86.rs @@ -0,0 +1,489 @@ +//! 32-bit x86 Linux system calls. +//! +//! There are two forms; `indirect_*` which take a callee, which allow calling +//! through the vDSO when possible, and plain forms, which use the `int 0x80` +//! instruction. +//! +//! Most `rustix` syscalls use the vsyscall mechanism rather than going using +//! `int 0x80` sequences, as vsyscall is much faster. +//! +//! Syscalls made with `int 0x80` preserve the flags register, while syscalls +//! made using vsyscall do not. + +#![allow(dead_code)] + +use crate::backend::reg::{ + ArgReg, FromAsm, RetReg, SyscallNumber, ToAsm, A0, A1, A2, A3, A4, A5, R0, +}; +use crate::backend::vdso_wrappers::SyscallType; +use core::arch::asm; + +#[inline] +pub(in crate::backend) unsafe fn indirect_syscall0( + callee: SyscallType, + nr: SyscallNumber<'_>, +) -> RetReg<R0> { + let r0; + asm!( + "call {callee}", + callee = in(reg) callee, + inlateout("eax") nr.to_asm() => r0, + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn indirect_syscall1( + callee: SyscallType, + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, +) -> RetReg<R0> { + let r0; + asm!( + "call {callee}", + callee = in(reg) callee, + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn indirect_syscall1_noreturn( + callee: SyscallType, + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, +) -> ! { + asm!( + "call {callee}", + callee = in(reg) callee, + in("eax") nr.to_asm(), + in("ebx") a0.to_asm(), + options(noreturn) + ) +} + +#[inline] +pub(in crate::backend) unsafe fn indirect_syscall2( + callee: SyscallType, + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, +) -> RetReg<R0> { + let r0; + asm!( + "call {callee}", + callee = in(reg) callee, + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn indirect_syscall3( + callee: SyscallType, + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, +) -> RetReg<R0> { + let r0; + asm!( + "call {callee}", + callee = in(reg) callee, + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn indirect_syscall4( + callee: SyscallType, + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, + a3: ArgReg<'_, A3>, +) -> RetReg<R0> { + let r0; + // a3 should go in esi, but `asm!` won't let us use it as an operand. + // Temporarily swap it into place, and then swap it back afterward. + // + // We hard-code the callee operand to use edi instead of `in(reg)` because + // even though we can't name esi as an operand, the compiler can use esi to + // satisfy `in(reg)`. + asm!( + "xchg esi, {a3}", + "call edi", + "xchg esi, {a3}", + a3 = in(reg) a3.to_asm(), + in("edi") callee, + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn indirect_syscall5( + callee: SyscallType, + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, + a3: ArgReg<'_, A3>, + a4: ArgReg<'_, A4>, +) -> RetReg<R0> { + let r0; + // Oof. a3 should go in esi, and `asm!` won't let us use that register as + // an operand. And we can't request stack slots. And there are no other + // registers free. Use eax as a temporary pointer to a slice, since it gets + // clobbered as the return value anyway. + asm!( + "push esi", + "push [eax + 0]", + "mov esi, [eax + 4]", + "mov eax, [eax + 8]", + "call [esp]", + "pop esi", + "pop esi", + inout("eax") &[callee as _, a3.to_asm(), nr.to_asm()] => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + in("edi") a4.to_asm(), + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn indirect_syscall6( + callee: SyscallType, + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, + a3: ArgReg<'_, A3>, + a4: ArgReg<'_, A4>, + a5: ArgReg<'_, A5>, +) -> RetReg<R0> { + let r0; + // Oof again. a3 should go in esi, and a5 should go in ebp, and `asm!` + // won't let us use either of those registers as operands. And we can't + // request stack slots. And there are no other registers free. Use eax as a + // temporary pointer to a slice, since it gets clobbered as the return + // value anyway. + // + // This is another reason that syscalls should be compiler intrinsics + // rather than inline asm. + asm!( + "push ebp", + "push esi", + "push [eax + 0]", + "mov esi, [eax + 4]", + "mov ebp, [eax + 8]", + "mov eax, [eax + 12]", + "call [esp]", + "pop esi", + "pop esi", + "pop ebp", + inout("eax") &[callee as _, a3.to_asm(), a5.to_asm(), nr.to_asm()] => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + in("edi") a4.to_asm(), + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall0_readonly(nr: SyscallNumber<'_>) -> RetReg<R0> { + let r0; + asm!( + "int $$0x80", + inlateout("eax") nr.to_asm() => r0, + options(nostack, preserves_flags, readonly) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall1(nr: SyscallNumber<'_>, a0: ArgReg<'_, A0>) -> RetReg<R0> { + let r0; + asm!( + "int $$0x80", + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + options(nostack, preserves_flags) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall1_readonly( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, +) -> RetReg<R0> { + let r0; + asm!( + "int $$0x80", + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + options(nostack, preserves_flags, readonly) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall1_noreturn(nr: SyscallNumber<'_>, a0: ArgReg<'_, A0>) -> ! { + asm!( + "int $$0x80", + in("eax") nr.to_asm(), + in("ebx") a0.to_asm(), + options(nostack, noreturn) + ) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall2( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, +) -> RetReg<R0> { + let r0; + asm!( + "int $$0x80", + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + options(nostack, preserves_flags) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall2_readonly( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, +) -> RetReg<R0> { + let r0; + asm!( + "int $$0x80", + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + options(nostack, preserves_flags, readonly) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall3( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, +) -> RetReg<R0> { + let r0; + asm!( + "int $$0x80", + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + options(nostack, preserves_flags) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall3_readonly( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, +) -> RetReg<R0> { + let r0; + asm!( + "int $$0x80", + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + options(nostack, preserves_flags, readonly) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall4( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, + a3: ArgReg<'_, A3>, +) -> RetReg<R0> { + let r0; + // a3 should go in esi, but `asm!` won't let us use it as an operand. + // Temporarily swap it into place, and then swap it back afterward. + asm!( + "xchg esi, {a3}", + "int $$0x80", + "xchg esi, {a3}", + a3 = in(reg) a3.to_asm(), + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + options(nostack, preserves_flags) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall4_readonly( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, + a3: ArgReg<'_, A3>, +) -> RetReg<R0> { + let r0; + asm!( + "xchg esi, {a3}", + "int $$0x80", + "xchg esi, {a3}", + a3 = in(reg) a3.to_asm(), + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + options(nostack, preserves_flags, readonly) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall5( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, + a3: ArgReg<'_, A3>, + a4: ArgReg<'_, A4>, +) -> RetReg<R0> { + let r0; + // As in `syscall4`, use xchg to handle a3. a4 should go in edi, and we can + // use that register as an operand. Unlike in `indirect_syscall5`, we don't + // have a `callee` operand taking up a register, so we have enough + // registers and don't need to use a slice. + asm!( + "xchg esi, {a3}", + "int $$0x80", + "xchg esi, {a3}", + a3 = in(reg) a3.to_asm(), + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + in("edi") a4.to_asm(), + options(nostack, preserves_flags) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall5_readonly( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, + a3: ArgReg<'_, A3>, + a4: ArgReg<'_, A4>, +) -> RetReg<R0> { + let r0; + // See the comments in `syscall5`. + asm!( + "xchg esi, {a3}", + "int $$0x80", + "xchg esi, {a3}", + a3 = in(reg) a3.to_asm(), + inlateout("eax") nr.to_asm() => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + in("edi") a4.to_asm(), + options(nostack, preserves_flags, readonly) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall6( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, + a3: ArgReg<'_, A3>, + a4: ArgReg<'_, A4>, + a5: ArgReg<'_, A5>, +) -> RetReg<R0> { + let r0; + // See the comments in `indirect_syscall6`. + asm!( + "push ebp", + "push esi", + "mov esi, [eax + 0]", + "mov ebp, [eax + 4]", + "mov eax, [eax + 8]", + "int $$0x80", + "pop esi", + "pop ebp", + inout("eax") &[a3.to_asm(), a5.to_asm(), nr.to_asm()] => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + in("edi") a4.to_asm(), + options(preserves_flags) + ); + FromAsm::from_asm(r0) +} + +#[inline] +pub(in crate::backend) unsafe fn syscall6_readonly( + nr: SyscallNumber<'_>, + a0: ArgReg<'_, A0>, + a1: ArgReg<'_, A1>, + a2: ArgReg<'_, A2>, + a3: ArgReg<'_, A3>, + a4: ArgReg<'_, A4>, + a5: ArgReg<'_, A5>, +) -> RetReg<R0> { + let r0; + // See the comments in `indirect_syscall6`. + asm!( + "push ebp", + "push esi", + "mov esi, [eax + 0]", + "mov ebp, [eax + 4]", + "mov eax, [eax + 8]", + "int $$0x80", + "pop esi", + "pop ebp", + inout("eax") &[a3.to_asm(), a5.to_asm(), nr.to_asm()] => r0, + in("ebx") a0.to_asm(), + in("ecx") a1.to_asm(), + in("edx") a2.to_asm(), + in("edi") a4.to_asm(), + options(preserves_flags, readonly) + ); + FromAsm::from_asm(r0) +} |