//
//go:nosplit
func sysFreeOS(v unsafe.Pointer, n uintptr) {
	munmap(v, n)
}

func sysFaultOS(v unsafe.Pointer, n uintptr) {
	mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE|_MAP_FIXED, -1, 0)
}

func sysReserveOS(v unsafe.Pointer, n uintptr) unsafe.Pointer {
	p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0)
	if err != 0 {
		return nil
	}
	return p
}

const _ENOMEM = 12

//
//go:nosplit
func sysFreeOS(v unsafe.Pointer, n uintptr) {
	munmap(v, n)
}

func sysFaultOS(v unsafe.Pointer, n uintptr) {
	mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE|_MAP_FIXED, -1, 0)
}

func sysReserveOS(v unsafe.Pointer, n uintptr) unsafe.Pointer {
	p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0)
	if err != 0 {
		return nil
	}
	return p
}

func sysMapOS(v unsafe.Pointer, n uintptr) {

func sysFaultOS(v unsafe.Pointer, n uintptr) {
	mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE|_MAP_FIXED, -1, 0)
}

// Indicates not to reserve swap space for the mapping.
const _sunosMAP_NORESERVE = 0x40

func sysReserveOS(v unsafe.Pointer, n uintptr) unsafe.Pointer {
	flags := int32(_MAP_ANON | _MAP_PRIVATE)
	if GOOS == "solaris" || GOOS == "illumos" {
		// Be explicit that we don't want to reserve swap space

}

func sysHugePageCollapseOS(v unsafe.Pointer, n uintptr) {
}

func sysMapOS(v unsafe.Pointer, n uintptr) {
}

func sysFaultOS(v unsafe.Pointer, n uintptr) {
}

func sysReserveOS(v unsafe.Pointer, n uintptr) unsafe.Pointer {
	lock(&memlock)
	var p unsafe.Pointer
	if uintptr(v) == bloc {
		// Address hint is the current end of memory,
		// so try to extend the address space.
		p = sbrk(n)

		throw("runtime: failed to release pages")
	}
}

func sysFaultOS(v unsafe.Pointer, n uintptr) {
	// SysUnused makes the memory inaccessible and prevents its reuse
	sysUnusedOS(v, n)
}

func sysReserveOS(v unsafe.Pointer, n uintptr) unsafe.Pointer {
	// v is just a hint.
	// First try at v.
	// This will fail if any of [v, v+n) is already reserved.

//go:nosplit
func sysFreeOS(v unsafe.Pointer, n uintptr) {
	munmap(v, n)
}

func sysFaultOS(v unsafe.Pointer, n uintptr) {
	mprotect(v, n, _PROT_NONE)
	madvise(v, n, _MADV_DONTNEED)
}

func sysReserveOS(v unsafe.Pointer, n uintptr) unsafe.Pointer {
	p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0)
	if err != 0 {
		return nil
	}
	return p
}

func sysMapOS(v unsafe.Pointer, n uintptr) {

// may use larger alignment, so the caller must be careful to realign the
// memory obtained by sysReserve.
func sysReserve(v unsafe.Pointer, n uintptr) unsafe.Pointer {
	return sysReserveOS(v, n)
}

// sysMap transitions a memory region from Reserved to Prepared. It ensures the
// memory region can be efficiently transitioned to Ready.
//
// sysStat must be non-nil.