On Sun, 13 Mar 2016 08:38:25 +0100 Carl-Daniel Hailfinger <[email protected]> wrote:
> On 13.03.2016 00:57, Stefan Tauner wrote: > > On Sun, 13 Mar 2016 00:26:41 +0100 > > Carl-Daniel Hailfinger <[email protected]> wrote: > > > >> On 13.03.2016 00:05, Stefan Tauner wrote: > >>> This came up when I was testing if building on SunOS still works > >>> on the buildbot's instance of OmniOS r151014 which is based on illumos. > >>> > >>> The fix is > >>> - to link against libnsl > >>> - a small C type fix in ich_descriptor_tool > >>> > >>> Signed-off-by: Stefan Tauner <[email protected]> > >>> Acked-by: Stefan Tauner <[email protected]> > >>> > >>> diff --git a/util/ich_descriptors_tool/ich_descriptors_tool.c > >>> b/util/ich_descriptors_tool/ich_descriptors_tool.c > >>> index c3d9ba1..ad3b6f0 100644 > >>> --- a/util/ich_descriptors_tool/ich_descriptors_tool.c > >>> +++ b/util/ich_descriptors_tool/ich_descriptors_tool.c > >>> @@ -170,7 +170,7 @@ int main(int argc, char *argv[]) > >>> usage(argv, "Seeking to the end of the file failed"); > >>> > >>> #ifdef HAVE_MMAP > >>> - buf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0); > >>> + buf = (uint32_t *)mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0); > >> The compiler may require that to stop complaining, but AFAICS there is a > >> real bug behind this. buf is sometimes casted to uint8_t *, and unless > >> I'm too sleepy already, this buffer violates the strict aliasing rules. > >> We can solve this with -fno-strict-aliasing, or fix the code. With a > >> code fix, in theory the problem should go away. > > While this is true it does not make much sense to try to fix it: > > - all accesses are read-only. The compiler can re-order as much as it > > wants, we won't get wrong results. No compiler writers however mean > > will make this explode. And that's the only potential problem with > > aliasing. > > - ich_descriptor.c intentionally uses undefined behavior by writing to > > some struct members and reading it through others to spare us from > > bit-shifting/masking. That was discussed at length back when I added > > it and since we use the code on x86 only it is fine. > > Ah right. > Acked-by: Carl-Daniel Hailfinger <[email protected]> Thanks, r1950. -- Kind regards/Mit freundlichen Grüßen, Stefan Tauner _______________________________________________ flashrom mailing list [email protected] https://www.flashrom.org/mailman/listinfo/flashrom
