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Add relibc fenv and sched POSIX implementations

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P3-fenv: x86_64 SSE/x87 inline asm for 10 FP environment functions
(feclearexcept, fegetenv, fegetexceptflag, fegetround, feholdexcept,
feraiseexcept, fesetenv, fesetexceptflag, fesetround, fetestexcept,
feupdateenv) with proper MXCSR and x87 CW register access.

P3-sched: 6 scheduler functions (sched_get_priority_max/min,
sched_getparam, sched_rr_get_interval, sched_setparam,
sched_setscheduler) with EINVAL for bad policy and no-op validation
since Redox has no real-time scheduler.
This commit is contained in:
Vasilito
2026-04-25 18:07:46 +01:00
parent ae1bce5e14
commit 530eb841db
3 changed files with 356 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
local/patches/relibc/P3-fenv.patch
+230
View File
@@ -0,0 +1,230 @@
diff --git a/src/header/_fenv/mod.rs b/src/header/_fenv/mod.rs
--- a/src/header/_fenv/mod.rs
+++ b/src/header/_fenv/mod.rs
@@ -4,82 +4,207 @@
use crate::platform::types::c_int;
-/// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/fenv.h.html>.
-pub const FE_ALL_EXCEPT: c_int = 0;
-/// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/fenv.h.html>.
-pub const FE_TONEAREST: c_int = 0;
+// x86_64 SSE floating-point exception flags (MXCSR bits 0-5, excluding denormal bit 1)
+pub const FE_INVALID: c_int = 0x01;
+pub const FE_DIVBYZERO: c_int = 0x04;
+pub const FE_OVERFLOW: c_int = 0x08;
+pub const FE_UNDERFLOW: c_int = 0x10;
+pub const FE_INEXACT: c_int = 0x20;
+/// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/fenv.h.html>.
+pub const FE_ALL_EXCEPT: c_int =
+ FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT;
+
+// x86_64 rounding modes (MXCSR bits 13-14, x87 CW bits 10-11)
+/// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/fenv.h.html>.
+pub const FE_TONEAREST: c_int = 0x000;
+pub const FE_DOWNWARD: c_int = 0x400;
+pub const FE_UPWARD: c_int = 0x800;
+pub const FE_TOWARDZERO: c_int = 0xC00;
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/fenv.h.html>.
pub type fexcept_t = u64;
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/fenv.h.html>.
#[repr(C)]
pub struct fenv_t {
- pub cw: u64,
+ pub cw: u32, // x87 control word (zero-extended from u16)
+ pub mxcsr: u32, // SSE MXCSR register
}
+/// Read the x87 FPU control word.
+#[inline]
+unsafe fn fnstcw() -> u16 {
+ let mut cw: u16 = 0;
+ core::arch::asm!(
+ "fnstcw ({0})",
+ in(reg) &mut cw,
+ options(nostack, preserves_flags)
+ );
+ cw
+}
+
+/// Load the x87 FPU control word.
+#[inline]
+unsafe fn fldcw(cw: u16) {
+ core::arch::asm!(
+ "fldcw ({0})",
+ in(reg) &cw,
+ options(nostack, preserves_flags)
+ );
+}
+
+/// Read the SSE MXCSR register.
+#[inline]
+unsafe fn stmxcsr() -> u32 {
+ let mut mxcsr: u32 = 0;
+ core::arch::asm!(
+ "stmxcsr ({0})",
+ in(reg) &mut mxcsr,
+ options(nostack, preserves_flags)
+ );
+ mxcsr
+}
+
+/// Write the SSE MXCSR register.
+#[inline]
+unsafe fn ldmxcsr(val: u32) {
+ core::arch::asm!(
+ "ldmxcsr ({0})",
+ in(reg) &val,
+ options(nostack, preserves_flags)
+ );
+}
+
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/feclearexcept.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn feclearexcept(excepts: c_int) -> c_int {
- unimplemented!();
+ let mask = (excepts & FE_ALL_EXCEPT) as u32;
+ if mask != 0 {
+ let mxcsr = stmxcsr();
+ ldmxcsr(mxcsr & !mask);
+ // Clear x87 status word exception flags
+ core::arch::asm!("fnclex", options(nostack, preserves_flags));
+ }
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/fegetenv.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn fegetenv(envp: *mut fenv_t) -> c_int {
- unimplemented!();
+ if envp.is_null() {
+ return 1;
+ }
+ (*envp).cw = fnstcw() as u32;
+ (*envp).mxcsr = stmxcsr();
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/fegetexceptflag.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn fegetexceptflag(flagp: *mut fexcept_t, excepts: c_int) -> c_int {
- unimplemented!();
+ if flagp.is_null() {
+ return 1;
+ }
+ let mxcsr = stmxcsr();
+ *flagp = (mxcsr & FE_ALL_EXCEPT as u32 & excepts as u32) as fexcept_t;
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/fegetround.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn fegetround() -> c_int {
- FE_TONEAREST
+ let mxcsr = stmxcsr();
+ (mxcsr & 0xC00) as c_int
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/feholdexcept.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn feholdexcept(envp: *mut fenv_t) -> c_int {
- unimplemented!();
+ if envp.is_null() {
+ return 1;
+ }
+ // Save current environment
+ (*envp).cw = fnstcw() as u32;
+ (*envp).mxcsr = stmxcsr();
+ // Clear all exception flags and set non-stop mode (unmask all exceptions)
+ // MXCSR: clear status bits 0-5, clear mask bits 7-12
+ let mxcsr = stmxcsr();
+ ldmxcsr(mxcsr & !(FE_ALL_EXCEPT as u32) & !((FE_ALL_EXCEPT as u32) << 7));
+ // x87: clear exception mask bits (bits 0-5 in CW) and clear status
+ let cw = fnstcw();
+ fldcw(cw & !0x3F);
+ core::arch::asm!("fnclex", options(nostack, preserves_flags));
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/feraiseexcept.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn feraiseexcept(excepts: c_int) -> c_int {
- unimplemented!();
+ let mask = (excepts & FE_ALL_EXCEPT) as u32;
+ if mask == 0 {
+ return 0;
+ }
+ // Set exception status flags in MXCSR
+ let mxcsr = stmxcsr();
+ ldmxcsr(mxcsr | mask);
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/fesetenv.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn fesetenv(envp: *const fenv_t) -> c_int {
- unimplemented!();
+ if envp.is_null() {
+ // Restore default environment
+ fldcw(0x037F); // x87 default CW: all exceptions masked, double precision
+ ldmxcsr(0x1F80); // MXCSR default: all exceptions masked, round-to-nearest
+ return 0;
+ }
+ fldcw((*envp).cw as u16);
+ ldmxcsr((*envp).mxcsr);
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/fesetexceptflag.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn fesetexceptflag(flagp: *const fexcept_t, excepts: c_int) -> c_int {
- unimplemented!();
+ if flagp.is_null() {
+ return 1;
+ }
+ let mask = (excepts & FE_ALL_EXCEPT) as u32;
+ let mxcsr = stmxcsr();
+ let flags = (*flagp as u32) & mask;
+ ldmxcsr((mxcsr & !mask) | flags);
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/fegetround.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn fesetround(round: c_int) -> c_int {
- unimplemented!();
+ let rm = round & 0xC00;
+ if rm != FE_TONEAREST && rm != FE_DOWNWARD && rm != FE_UPWARD && rm != FE_TOWARDZERO {
+ return 1;
+ }
+ // Set rounding mode in MXCSR (bits 13-14)
+ let mxcsr = stmxcsr();
+ ldmxcsr((mxcsr & !0xC00u32) | rm as u32);
+ // Set rounding mode in x87 CW (bits 10-11)
+ let cw = fnstcw();
+ fldcw((cw & !0x0C00) | rm as u16);
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/fetestexcept.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn fetestexcept(excepts: c_int) -> c_int {
- unimplemented!();
+ let mxcsr = stmxcsr();
+ (mxcsr & FE_ALL_EXCEPT as u32 & excepts as u32) as c_int
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/feupdateenv.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn feupdateenv(envp: *const fenv_t) -> c_int {
- unimplemented!();
+ let mxcsr = stmxcsr();
+ let excepts = (mxcsr & FE_ALL_EXCEPT as u32) as c_int;
+ if fesetenv(envp) != 0 {
+ return 1;
+ }
+ feraiseexcept(excepts);
+ 0
}
local/patches/relibc/P3-sched.patch
+124
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@@ -0,0 +1,124 @@
diff --git a/src/header/sched/mod.rs b/src/header/sched/mod.rs
--- a/src/header/sched/mod.rs
+++ b/src/header/sched/mod.rs
@@ -2,9 +2,11 @@
//!
//! See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sched.h.html>.
use crate::{
error::ResultExt,
- header::bits_timespec::timespec,
+ header::{bits_timespec::timespec, errno},
platform::{
- Pal, Sys,
+ self, Pal, Sys,
types::{c_int, pid_t},
},
};
@@ -29,42 +31,67 @@
pub const SCHED_OTHER: c_int = 2;
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/sched_get_priority_max.html>.
// #[unsafe(no_mangle)]
pub extern "C" fn sched_get_priority_max(policy: c_int) -> c_int {
- todo!()
+ match policy {
+ SCHED_FIFO | SCHED_RR => 99,
+ SCHED_OTHER => 0,
+ _ => {
+ platform::ERRNO.set(errno::EINVAL);
+ -1
+ }
+ }
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/sched_get_priority_max.html>.
// #[unsafe(no_mangle)]
pub extern "C" fn sched_get_priority_min(policy: c_int) -> c_int {
- todo!()
+ match policy {
+ SCHED_FIFO | SCHED_RR => 0,
+ SCHED_OTHER => 0,
+ _ => {
+ platform::ERRNO.set(errno::EINVAL);
+ -1
+ }
+ }
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/sched_getparam.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn sched_getparam(pid: pid_t, param: *mut sched_param) -> c_int {
- todo!()
+ if param.is_null() {
+ platform::ERRNO.set(errno::EINVAL);
+ return -1;
+ }
+ // Redox has no real-time scheduler; return default params
+ (*param).sched_priority = 0;
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/sched_rr_get_interval.html>.
// #[unsafe(no_mangle)]
pub extern "C" fn sched_rr_get_interval(pid: pid_t, time: *const timespec) -> c_int {
- todo!()
+ if time.is_null() {
+ platform::ERRNO.set(errno::EINVAL);
+ return -1;
+ }
+ // Redox has no real-time scheduler; report a nominal 1-second round-robin interval
+ unsafe {
+ (*(time as *mut timespec)).tv_sec = 1;
+ (*(time as *mut timespec)).tv_nsec = 0;
+ }
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/sched_setparam.html>.
// #[unsafe(no_mangle)]
pub unsafe extern "C" fn sched_setparam(pid: pid_t, param: *const sched_param) -> c_int {
- todo!()
+ if param.is_null() {
+ platform::ERRNO.set(errno::EINVAL);
+ return -1;
+ }
+ let priority = (*param).sched_priority;
+ if priority < 0 || priority > 99 {
+ platform::ERRNO.set(errno::EINVAL);
+ return -1;
+ }
+ // Redox has no real-time scheduler; validate and succeed as a no-op
+ 0
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/sched_setscheduler.html>.
// #[unsafe(no_mangle)]
pub extern "C" fn sched_setscheduler(
pid: pid_t,
policy: c_int,
param: *const sched_param,
) -> c_int {
- todo!()
+ if param.is_null() {
+ platform::ERRNO.set(errno::EINVAL);
+ return -1;
+ }
+ match policy {
+ SCHED_FIFO | SCHED_RR | SCHED_OTHER => {
+ let priority = unsafe { (*param).sched_priority };
+ if priority < 0 || priority > 99 {
+ platform::ERRNO.set(errno::EINVAL);
+ return -1;
+ }
+ // Redox has no real-time scheduler; validate and succeed as a no-op
+ 0
+ }
+ _ => {
+ platform::ERRNO.set(errno::EINVAL);
+ -1
+ }
+ }
}
/// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/sched_yield.html>.
recipes/core/relibc/recipe.toml
+2
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@@ -34,6 +34,8 @@ patches = [
"../../../local/patches/relibc/P3-sysv-sem-impl.patch", "../../../local/patches/relibc/P3-sysv-sem-impl.patch",
"../../../local/patches/relibc/P3-sysv-shm-impl.patch", "../../../local/patches/relibc/P3-sysv-shm-impl.patch",
"../../../local/patches/relibc/P3-waitid-header.patch", "../../../local/patches/relibc/P3-waitid-header.patch",
"../../../local/patches/relibc/P3-fenv.patch",
"../../../local/patches/relibc/P3-sched.patch",
] ]
[build] [build]