On Wed, Nov 23, 2016 at 08:56:25PM +0000, Winkler, Tomas wrote: > > On Wed, Nov 23, 2016 at 01:04:54PM +0200, Tomas Winkler wrote: > > > Use get_unaligned_be32 as b32_to_cpu doesn't work correctly on all > > > platforms for unaligned access. > > > > > > The fix doesn't cover all the cases as also some cast structures have > > > members on unaligned addresses. > > > > I think this is a good idea.. > > > > > @@ -353,8 +353,8 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 > > *buf, size_t bufsiz, > > > if (bufsiz > TPM_BUFSIZE) > > > bufsiz = TPM_BUFSIZE; > > > > > > - count = be32_to_cpu(*((__be32 *) (buf + 2))); > > > - ordinal = be32_to_cpu(*((__be32 *) (buf + 6))); > > > + count = get_unaligned_be32(buf + 2); > > > + ordinal = get_unaligned_be32(buf + 6); > > > > But lets fix this better and get rid of the constants too... > > > const tpm_input_header *hdr = buf; > > count = be32_to_cpu(hdr->length); > > ordinal = be32_to_cpu(hdr->ordinal); > > > > Compiler will take care of unaligned for __packed. > > Yes, compiler takes care at performance penalty but probably we > don't care about that much,
Hmm? get_unaligned_be32 boils down to the same __packed construct. As is today we must be hitting the in-kernel unaligned access trap (eg on ARM) which is *very* expensive so this is a very worthwhile fix ... Jason ------------------------------------------------------------------------------ _______________________________________________ tpmdd-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/tpmdd-devel
