Re: [PATCH] m68k: asm/io.h: mark mmio read addresses as const
From: Geert Uytterhoeven
Date: Mon Oct 02 2023 - 09:12:37 EST
Hi Arnd,
On Mon, Sep 25, 2023 at 5:53 PM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> Passing constant __iomem tokens into the readl() family of helpers
> or any of the others causes a warning on m68k:
>
> include/asm-generic/io.h: In function 'ioread8_rep':
> arch/m68k/include/asm/io_mm.h:375:44: warning: passing argument 1 of 'raw_insb' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
> 375 | #define readsb(port, buf, nr) raw_insb((port), (u8
>
> Add a 'const' modifier to the pointers to shut up the warnings here.
>
> Closes: https://lore.kernel.org/oe-kbuild-all/202309251926.bPl23AhG-lkp@xxxxxxxxx/
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Thanks for your patch!
> --- a/arch/m68k/include/asm/raw_io.h
> +++ b/arch/m68k/include/asm/raw_io.h
> @@ -17,15 +17,15 @@
> * two accesses to memory, which may be undesirable for some devices.
> */
> #define in_8(addr) \
> - ({ u8 __v = (*(__force volatile u8 *) (unsigned long)(addr)); __v; })
> + ({ u8 __v = (*(__force const volatile u8 *) (unsigned long)(addr)); __v; })
> #define in_be16(addr) \
> - ({ u16 __v = (*(__force volatile u16 *) (unsigned long)(addr)); __v; })
> + ({ u16 __v = (*(__force const volatile u16 *) (unsigned long)(addr)); __v; })
> #define in_be32(addr) \
> - ({ u32 __v = (*(__force volatile u32 *) (unsigned long)(addr)); __v; })
> + ({ u32 __v = (*(__force const volatile u32 *) (unsigned long)(addr)); __v; })
> #define in_le16(addr) \
> - ({ u16 __v = le16_to_cpu(*(__force volatile __le16 *) (unsigned long)(addr)); __v; })
> + ({ u16 __v = le16_to_cpu(*(__force const volatile __le16 *) (unsigned long)(addr)); __v; })
> #define in_le32(addr) \
> - ({ u32 __v = le32_to_cpu(*(__force volatile __le32 *) (unsigned long)(addr)); __v; })
> + ({ u32 __v = le32_to_cpu(*(__force const volatile __le32 *) (unsigned long)(addr)); __v; })
>
> #define out_8(addr,b) (void)((*(__force volatile u8 *) (unsigned long)(addr)) = (b))
> #define out_be16(addr,w) (void)((*(__force volatile u16 *) (unsigned long)(addr)) = (w))
Shouldn't a similar change be made to rom_in_{8,be16,le16}()?
I can do that while applying...
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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