// Test that the error value returned by mmap is positive, as that is
// what the code in mem_bsd.go, mem_darwin.go, and mem_linux.go expects.
// See the uses of ENOMEM in sysMap in those files.
func TestMmapErrorSign(t *testing.T) {
p := runtime.Mmap(nil, ^uintptr(0)&^(runtime.GetPhysPageSize()-1), 0, runtime.MAP_ANON|runtime.MAP_PRIVATE, -1, 0)
// The runtime.mmap function is nosplit, but t.Errorf is not.
// Reset the pointer so that we don't get an "invalid stack
// pointer" error from t.Errorf if we call it.
v := uintptr(p)
p = nil
if v != runtime.ENOMEM {
t.Errorf("mmap = %v, want %v", v, runtime.ENOMEM)
}
}
func TestPhysPageSize(t *testing.T) {
// Mmap fails if the address is not page aligned, so we can
// use this to test if the page size is the true page size.
ps := runtime.GetPhysPageSize()
// Get a region of memory to play with. This should be page-aligned.
b := uintptr(runtime.Mmap(nil, 2*ps, 0, runtime.MAP_ANON|runtime.MAP_PRIVATE, -1, 0))
if b < 4096 {
t.Fatalf("Mmap: %v", b)
}
// Mmap should fail at a half page into the buffer.
err := uintptr(runtime.Mmap(unsafe.Pointer(uintptr(b)+ps/2), ps, 0, runtime.MAP_ANON|runtime.MAP_PRIVATE|runtime.MAP_FIXED, -1, 0))
if err >= 4096 {
t.Errorf("Mmap should have failed with half-page alignment %d, but succeeded: %v", ps/2, err)
}
// Mmap should succeed at a full page into the buffer.
err = uintptr(runtime.Mmap(unsafe.Pointer(uintptr(b)+ps), ps, 0, runtime.MAP_ANON|runtime.MAP_PRIVATE|runtime.MAP_FIXED, -1, 0))
if err < 4096 {
t.Errorf("Mmap at full-page alignment %d failed: %v", ps, err)
}
}