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// On x86-64, the following registers are used for args 1-6:
// arg1: %rdi
// arg2: %rsi
// arg3: %rdx
// arg4: %r10
// arg5: %r8
// arg6: %r9
//
// rax is used for both the syscall number and the syscall return value.
//
// rcx and r11 are always clobbered. syscalls can also modify memory. With the
// `asm!()` macro, it is assumed that memory is clobbered unless the nomem
// option is specified.
use core::arch::asm;
use crate::arch::x86_64::Sysno;
/// Issues a raw system call with 0 arguments.
///
/// # Safety
///
/// Running a system call is inherently unsafe. It is the caller's
/// responsibility to ensure safety.
#[inline]
pub unsafe fn syscall0(n: Sysno) -> usize {
let mut ret: usize;
asm!(
"syscall",
inlateout("rax") n as usize => ret,
out("rcx") _, // rcx is used to store old rip
out("r11") _, // r11 is used to store old rflags
options(nostack, preserves_flags)
);
ret
}
/// Issues a raw system call with 1 argument.
///
/// # Safety
///
/// Running a system call is inherently unsafe. It is the caller's
/// responsibility to ensure safety.
#[inline]
pub unsafe fn syscall1(n: Sysno, arg1: usize) -> usize {
let mut ret: usize;
asm!(
"syscall",
inlateout("rax") n as usize => ret,
in("rdi") arg1,
out("rcx") _, // rcx is used to store old rip
out("r11") _, // r11 is used to store old rflags
options(nostack, preserves_flags)
);
ret
}
/// Issues a raw system call with 2 arguments.
///
/// # Safety
///
/// Running a system call is inherently unsafe. It is the caller's
/// responsibility to ensure safety.
#[inline]
pub unsafe fn syscall2(n: Sysno, arg1: usize, arg2: usize) -> usize {
let mut ret: usize;
asm!(
"syscall",
inlateout("rax") n as usize => ret,
in("rdi") arg1,
in("rsi") arg2,
out("rcx") _, // rcx is used to store old rip
out("r11") _, // r11 is used to store old rflags
options(nostack, preserves_flags)
);
ret
}
/// Issues a raw system call with 3 arguments.
///
/// # Safety
///
/// Running a system call is inherently unsafe. It is the caller's
/// responsibility to ensure safety.
#[inline]
pub unsafe fn syscall3(
n: Sysno,
arg1: usize,
arg2: usize,
arg3: usize,
) -> usize {
let mut ret: usize;
asm!(
"syscall",
inlateout("rax") n as usize => ret,
in("rdi") arg1,
in("rsi") arg2,
in("rdx") arg3,
out("rcx") _, // rcx is used to store old rip
out("r11") _, // r11 is used to store old rflags
options(nostack, preserves_flags)
);
ret
}
/// Issues a raw system call with 4 arguments.
///
/// # Safety
///
/// Running a system call is inherently unsafe. It is the caller's
/// responsibility to ensure safety.
#[inline]
pub unsafe fn syscall4(
n: Sysno,
arg1: usize,
arg2: usize,
arg3: usize,
arg4: usize,
) -> usize {
let mut ret: usize;
asm!(
"syscall",
inlateout("rax") n as usize => ret,
in("rdi") arg1,
in("rsi") arg2,
in("rdx") arg3,
in("r10") arg4,
out("rcx") _, // rcx is used to store old rip
out("r11") _, // r11 is used to store old rflags
options(nostack, preserves_flags)
);
ret
}
/// Issues a raw system call with 5 arguments.
///
/// # Safety
///
/// Running a system call is inherently unsafe. It is the caller's
/// responsibility to ensure safety.
#[inline]
pub unsafe fn syscall5(
n: Sysno,
arg1: usize,
arg2: usize,
arg3: usize,
arg4: usize,
arg5: usize,
) -> usize {
let mut ret: usize;
asm!(
"syscall",
inlateout("rax") n as usize => ret,
in("rdi") arg1,
in("rsi") arg2,
in("rdx") arg3,
in("r10") arg4,
in("r8") arg5,
out("rcx") _, // rcx is used to store old rip
out("r11") _, // r11 is used to store old rflags
options(nostack, preserves_flags)
);
ret
}
/// Issues a raw system call with 6 arguments.
///
/// # Safety
///
/// Running a system call is inherently unsafe. It is the caller's
/// responsibility to ensure safety.
#[inline]
pub unsafe fn syscall6(
n: Sysno,
arg1: usize,
arg2: usize,
arg3: usize,
arg4: usize,
arg5: usize,
arg6: usize,
) -> usize {
let mut ret: usize;
asm!(
"syscall",
inlateout("rax") n as usize => ret,
in("rdi") arg1,
in("rsi") arg2,
in("rdx") arg3,
in("r10") arg4,
in("r8") arg5,
in("r9") arg6,
out("rcx") _, // rcx is used to store old rip
out("r11") _, // r11 is used to store old rflags
options(nostack, preserves_flags)
);
ret
}