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chore: don't benchmark binary crate; centralize assembly helpers

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Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: Ia24cb1647df93034937a8fcd6cad895c6a6a6964
This commit is contained in:
raf 2026-03-27 13:49:26 +03:00
commit 1c781aff56
Signed by: NotAShelf
GPG key ID: 29D95B64378DB4BF
7 changed files with 203 additions and 103 deletions
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75
crates/lib/src/uptime.rs
View file

@ -1,5 +1,7 @@
use std::{io, mem::MaybeUninit};
use crate::syscall::sys_sysinfo;
/// Faster integer to string conversion without the formatting overhead.
#[inline]
fn itoa(mut n: u64, buf: &mut [u8]) -> &str {
@ -17,79 +19,6 @@ fn itoa(mut n: u64, buf: &mut [u8]) -> &str {
unsafe { std::str::from_utf8_unchecked(&buf[i..]) }
}
/// Raw buffer for the `sysinfo(2)` syscall.
///
/// In the Linux ABI `uptime` is a `long` at offset 0. The remaining fields are
/// not needed, but are declared to give the struct its correct size (112 bytes
/// on 64-bit Linux).
///
/// The layout matches the kernel's `struct sysinfo` *exactly*:
/// `mem_unit` ends at offset 108, then 4 bytes of implicit padding to 112.
#[repr(C)]
struct SysInfo {
uptime: i64,
loads: [u64; 3],
totalram: u64,
freeram: u64,
sharedram: u64,
bufferram: u64,
totalswap: u64,
freeswap: u64,
procs: u16,
_pad: u16,
_pad2: u32, // alignment padding to reach 8-byte boundary for totalhigh
totalhigh: u64,
freehigh: u64,
mem_unit: u32,
// 4 bytes implicit trailing padding to reach 112 bytes total; no field
// needed
}
/// Direct `sysinfo(2)` syscall using inline assembly
///
/// # Safety
///
/// The caller must ensure the sysinfo pointer is valid.
#[inline]
unsafe fn sys_sysinfo(info: *mut SysInfo) -> i64 {
#[cfg(target_arch = "x86_64")]
{
let ret: i64;
unsafe {
std::arch::asm!(
"syscall",
in("rax") 99_i64, // __NR_sysinfo
in("rdi") info,
out("rcx") _,
out("r11") _,
lateout("rax") ret,
options(nostack)
);
}
ret
}
#[cfg(target_arch = "aarch64")]
{
let ret: i64;
unsafe {
std::arch::asm!(
"svc #0",
in("x8") 179_i64, // __NR_sysinfo
in("x0") info,
lateout("x0") ret,
options(nostack)
);
}
ret
}
#[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
{
compile_error!("Unsupported architecture for inline assembly syscalls");
}
}
/// Gets the current system uptime.
///
/// # Errors