Re: [PATCH RFC v4 net-next 01/26] net: filter: add "load 64-bit immediate" eBPF instruction
From: H. Peter Anvin
Date: Wed Aug 13 2014 - 17:17:20 EST
On 08/13/2014 02:02 PM, Alexei Starovoitov wrote:
> On Wed, Aug 13, 2014 at 11:35 AM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>> The compiler can still think of it as a single insn, though, but some
>> future compiler might not.
> I think that would be very dangerous.
> compiler (user space) and kernel interpreter must have the same
> understanding of ISA.
Only at the point of the interface layer. The compiler can treat it as
a single instruction internally, the JIT can do peephole optimization,
but as long as the instruction stream at the boundary matches the
official ISA spec everything is fine.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/