On Thu, Mar 4, 2021 at 3:30 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote: > > Implement BPF_AND, BPF_OR and BPF_XOR as the existing BPF_ADD. Since > the corresponding machine instructions return the old value, BPF_FETCH > happens by itself, the only additional thing that is required is > zero-extension. > > There is no single instruction that implements BPF_XCHG on s390, so use > a COMPARE AND SWAP loop. > > BPF_CMPXCHG, on the other hand, can be implemented by a single COMPARE > AND SWAP. Zero-extension is automatically inserted by the verifier. > > Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> > --- > > Note: this patch depends on [1]; posting now to get some feedback. > > [1] https://lore.kernel.org/bpf/20210303110402.3965626-1-jackmanb@xxxxxxxxxx/ lgtm. This patch will sit in patchwork until bpf is merged with bpf-next.
