os_linux32.go

     1  // Copyright 2025 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build linux && (386 || arm || mips || mipsle || (gccgo && (ppc || s390)))
     6  
     7  package runtime
     8  
     9  import (
    10  	"internal/runtime/atomic"
    11  	"unsafe"
    12  )
    13  
    14  //go:noescape
    15  func futex_time32(addr unsafe.Pointer, op int32, val uint32, ts *timespec32, addr2 unsafe.Pointer, val3 uint32) int32
    16  
    17  //go:noescape
    18  func futex_time64(addr unsafe.Pointer, op int32, val uint32, ts *timespec, addr2 unsafe.Pointer, val3 uint32) int32
    19  
    20  var isFutexTime32bitOnly atomic.Bool
    21  
    22  //go:nosplit
    23  func futex(addr unsafe.Pointer, op int32, val uint32, ts *timespec, addr2 unsafe.Pointer, val3 uint32) int32 {
    24  	if !isFutexTime32bitOnly.Load() {
    25  		ret := futex_time64(addr, op, val, ts, addr2, val3)
    26  		// futex_time64 is only supported on Linux 5.0+
    27  		if ret != -_ENOSYS {
    28  			return ret
    29  		}
    30  		isFutexTime32bitOnly.Store(true)
    31  	}
    32  	// Downgrade ts.
    33  	var ts32 timespec32
    34  	var pts32 *timespec32
    35  	if ts != nil {
    36  		ts32.setNsec(ts.tv_sec*1e9 + ts.tv_nsec)
    37  		pts32 = &ts32
    38  	}
    39  	return futex_time32(addr, op, val, pts32, addr2, val3)
    40  }
    41  
    42  //go:noescape
    43  func timer_settime32(timerid int32, flags int32, new, old *itimerspec32) int32
    44  
    45  //go:noescape
    46  func timer_settime64(timerid int32, flags int32, new, old *itimerspec) int32
    47  
    48  var isSetTime32bitOnly atomic.Bool
    49  
    50  //go:nosplit
    51  func timer_settime(timerid int32, flags int32, new, old *itimerspec) int32 {
    52  	if !isSetTime32bitOnly.Load() {
    53  		ret := timer_settime64(timerid, flags, new, old)
    54  		// timer_settime64 is only supported on Linux 5.0+
    55  		if ret != -_ENOSYS {
    56  			return ret
    57  		}
    58  		isSetTime32bitOnly.Store(true)
    59  	}
    60  
    61  	var newts, oldts itimerspec32
    62  	var new32, old32 *itimerspec32
    63  
    64  	if new != nil {
    65  		newts.it_interval.setNsec(new.it_interval.tv_sec*1e9 + new.it_interval.tv_nsec)
    66  		newts.it_value.setNsec(new.it_value.tv_sec*1e9 + new.it_value.tv_nsec)
    67  		new32 = &newts
    68  	}
    69  
    70  	if old != nil {
    71  		oldts.it_interval.setNsec(old.it_interval.tv_sec*1e9 + old.it_interval.tv_nsec)
    72  		oldts.it_value.setNsec(old.it_value.tv_sec*1e9 + old.it_value.tv_nsec)
    73  		old32 = &oldts
    74  	}
    75  
    76  	// Fall back to 32-bit timer
    77  	return timer_settime32(timerid, flags, new32, old32)
    78  }
    79
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