Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Wed, 15 Sep 2021 09:13:11 +0200 | Subject | Re: [PATCH v2 1/4] compiler.h: Introduce absolute_pointer macro |
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Hi Günter,
On Wed, Sep 15, 2021 at 5:52 AM Guenter Roeck <linux@roeck-us.net> wrote: > absolute_pointer() disassociates a pointer from its originating symbol > type and context. Use it to prevent compiler warnings/errors such as > > drivers/net/ethernet/i825xx/82596.c: In function 'i82596_probe': > ./arch/m68k/include/asm/string.h:72:25: error: > '__builtin_memcpy' reading 6 bytes from a region of size 0 > [-Werror=stringop-overread] > > Such warnings may be reported by gcc 11.x for string and memory operations > on fixed addresses. > > Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> > Signed-off-by: Guenter Roeck <linux@roeck-us.net> > --- > v2: No change > > include/linux/compiler.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > index b67261a1e3e9..3d5af56337bd 100644 > --- a/include/linux/compiler.h > +++ b/include/linux/compiler.h > @@ -188,6 +188,8 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val, > (typeof(ptr)) (__ptr + (off)); }) > #endif > > +#define absolute_pointer(val) RELOC_HIDE((void *)(val), 0)
I guess we're not worried about "val" being evaluated multiple times inside RELOC_HIDE(), as this is mainly intended for constants?
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
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