From: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx> Date: Wed, 21 Oct 2015 08:36:28 -0400 > + memcpy((u8 *)p, &tmp, sizeof(tmp)); memcpy() _never_ works for avoiding unaligned accessed. I repeat, no matter what you do, no matter what kinds of casts or fancy typing you use, memcpy() _never_ works for this purpose. The compiler knows that the pointer you are using is supposed to be at least 8 byte aligned, it can look through the cast and that's completely legitimate for it to do. So it can legitimately inline emit loads and stores to implement the memcpy() and those will still get the unaligned accesses. There is one and only one portable way to access unaligned data, and that is with the get_unaligned() and put_unaligned() helpers. Userland must do something similar to deal with this situation as well. -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
