On 9/15/21 12:13 AM, Geert Uytterhoeven wrote:
Hi Günter, On Wed, Sep 15, 2021 at 5:52 AM Guenter Roeck <linux@xxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> --- 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?
No, we are not. It is quite similar to RELOC_HIDE() in that regard. Guenter
