[PATCH 03/13] riscv: compat: Add basic compat date type implementation

[Arnd Bergmann]

On Wed, Dec 22, 2021 at 1:03 PM Guo Ren <guoren at kernel.org> wrote:
> On Wed, Dec 22, 2021 at 1:13 AM Arnd Bergmann <arnd at arndb.de> wrote:
> > On Tue, Dec 21, 2021 at 5:35 PM <guoren at kernel.org> wrote:
> >
> > > +struct compat_stat {
> > > +       compat_ulong_t  st_dev;
> > > +       compat_ulong_t  st_ino;
> > > +       compat_uint_t   st_mode;
> > > +       compat_uint_t   st_nlink;
> >
> > You should not need a compat_stat, because native rv32 does not have a
> > stat() syscall.
> We need it:
>
> $ make ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu-
> EXTRA_CFLAGS+=-g O=../build-riscv/ Image -j > /dev/null
> /home/guoren/source/kernel/riscv-linux/fs/stat.c: In function 'cp_compat_stat':
> /home/guoren/source/kernel/riscv-linux/fs/stat.c:645:21: error:
> storage size of 'tmp' isn't known
>   645 |  struct compat_stat tmp;

I think that's just a bug in fs/stat.c. Every other architecture so
far needed it,
just not riscv, so we should add an appropriate #ifdef here. I would replace
#ifdef CONFIG_COMPAT around these with __ARCH_WANT_COMPAT_STAT
and then change all other compat architectures to define that depending
on the configuration.

        Arnd