Re: [patch 1/2] m68k: runtime patching infrastructure

Geert Uytterhoeven
2007-05-30T07:06:21Z

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: TEXT/PLAIN; charset=UTF-8, Size: 2018 bytes --]

On Wed, 30 May 2007, Eric Dumazet wrote:
> Andrew Morton a écrit :
> > On Mon, 28 May 2007 21:16:31 +0200
> > Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> >
> > > --- a/include/asm-m68k/module.h
> > > +++ b/include/asm-m68k/module.h
> > > @@ -1,7 +1,38 @@
> > > #ifndef _ASM_M68K_MODULE_H
> > > #define _ASM_M68K_MODULE_H
> > > -struct mod_arch_specific { };
> > > +
> > > +struct mod_arch_specific {
> > > + struct m68k_fixup_info *fixup_start, *fixup_end;
> > > +};
> >
> > Here we use struct m68k_fixup_info.
> >
> > > +#define MODULE_ARCH_INIT { \
> > > + .fixup_start = __start_fixup, \
> > > + .fixup_end = __stop_fixup, \
> > > +}
> > > +
> > > #define Elf_Shdr Elf32_Shdr
> > > #define Elf_Sym Elf32_Sym
> > > #define Elf_Ehdr Elf32_Ehdr
> > > +
> > > +
> > > +enum m68k_fixup_type {
> > > + m68k_fixup_memoffset,
> > > +};
> > > +
> > > +struct m68k_fixup_info {
> > > + enum m68k_fixup_type type;
> > > + void *addr;
> > > +};
> >
> > and later we define it.
> >
> > How come it doesn't spit warnings?
> >
> > I think it could be tightened up even if it happens not to warn?
>
>
> struct a {
> struct not_yet_defined *start, *end;
> };
>
> struct not_yet_defined {
> void *foo;
> };
>
> Is a valid and gives no warnings.

I was puzzled by this as well, as there were no compiler warnings...

Apparently you get a warning only if the _first_ occurrence of a struct
is declared inside a parameter list of a function.

So even

struct a {
struct not_yet_defined *start, *end;
};

extern void f(struct not_yet_defined *start);

struct not_yet_defined {
void *foo;
};

doesn't give a warning, because the first occurence is inside the
definition of struct a.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds