On Thu, Jul 4, 2019 at 1:34 AM Arnd Bergmann <a...@arndb.de> wrote:
>
> On Thu, Jul 4, 2019 at 12:18 AM Alistair Francis <alistai...@gmail.com> wrote:
> > On Wed, Jul 3, 2019 at 12:47 PM Arnd Bergmann <a...@arndb.de> wrote:
> > > On Wed, Jul 3, 2019 at 8:45 PM Alistair Francis <alistai...@gmail.com>
> > > wrote:
> > > > What I don't understand though is how that impacted this struct, it
> > > > doesn't use clock_t at all, everything in the struct is an int or
> > > > void*.
> > >
> > > si_utime/si_stime in siginfo are clock_t.
> >
> > But they are further down the struct. I just assumed that GCC would
> > align those as required, I guess it aligns the start of the struct to
> > match some 64-bit members which seems strange.
>
> These are the regular struct alignment rules. Essentially you would
> get something like
>
> struct s {
> int a;
> int b;
> int c;
> union {
> int d;
> long long e;
> };
> int f;
> };
>
> Since 'e' has 8 byte alignment, the same is true for the union,
> and putting the union in a struct also requires the same alignment
> for the struct itself, so now you get padding after 'c' and 'f'.
Now that I think about it more it does make sense. Thanks for the help
with this and all the glibc stuff.
I have a new patch set that seems to work on RV32 and RV64. I'm now
hitting issues with syscalls that glibc doesn't use but other projects
do like io_getevents in OpenSSL.
Alistair
>
> Arnd
