Re: [PATCH v2 1/4] compiler.h: Introduce absolute_pointer macro
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2021-09-15 07:13:28
Also in:
linux-alpha, lkml
Hi Günter, On Wed, Sep 15, 2021 at 5:52 AM Guenter Roeck [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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