is a read or write operation on a pointer value atomic in golang?

Question

Is the size of a pointer value 32 bits or 64 bits in golang when building with GOARCH=amd64 option specified and running on 64-bit OS?

If it's 64-bit size, is a global pointer value 8-byte aligned in memory so that a read or write operation of that pointer value is carried out atomically?

For example, in the following code, is it possible that the global pointer p is only partially updated when the read goroutine read the pointer?

var p *int

void main() {
    i := 1
    p = &i
    go func() {
        fmt.Println(*p)
    }()
}

The scenario I'm concerning is that there is only one write but multiple reads on a global pointer value, and reading of an old value of the pointer is not important. Thanks in advance!