[PATCH] m68k: asm/io.h: mark mmio read addresses as const

[PATCH] m68k: asm/io.h: mark mmio read addresses as const

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

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@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/m68k/include/asm/raw_io.h | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/arch/m68k/include/asm/raw_io.h b/arch/m68k/include/asm/raw_io.h
index 3ba40bc1dfaa9..4bc29e57e57fb 100644
--- 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))
@@ -98,7 +98,8 @@
 #define raw_rom_outw(val, port) rom_out_be16((port), (val))
 #endif /* CONFIG_ATARI_ROM_ISA */
 
-static inline void raw_insb(volatile u8 __iomem *port, u8 *buf, unsigned int len)
+static inline void raw_insb(const volatile u8 __iomem *port, u8 *buf,
+			    unsigned int len)
 {
 	unsigned int i;
 
@@ -146,7 +147,7 @@ static inline void raw_outsb(volatile u8 __iomem *port, const u8 *buf,
 	}
 }
 
-static inline void raw_insw(volatile u16 __iomem *port, u16 *buf, unsigned int nr)
+static inline void raw_insw(volatile const u16 __iomem *port, u16 *buf, unsigned int nr)
 {
 	unsigned int tmp;
 
@@ -225,7 +226,7 @@ static inline void raw_outsw(volatile u16 __iomem *port, const u16 *buf,
 	}
 }
 
-static inline void raw_insl(volatile u32 __iomem *port, u32 *buf, unsigned int nr)
+static inline void raw_insl(const volatile u32 __iomem *port, u32 *buf, unsigned int nr)
 {
 	unsigned int tmp;
 
@@ -305,7 +306,7 @@ static inline void raw_outsl(volatile u32 __iomem *port, const u32 *buf,
 }
 
 
-static inline void raw_insw_swapw(volatile u16 __iomem *port, u16 *buf,
+static inline void raw_insw_swapw(const volatile u16 __iomem *port, u16 *buf,
 				  unsigned int nr)
 {
     if ((nr) % 8)
@@ -413,7 +414,8 @@ static inline void raw_outsw_swapw(volatile u16 __iomem *port, const u16 *buf,
 
 
 #if defined(CONFIG_ATARI_ROM_ISA)
-static inline void raw_rom_insb(volatile u8 __iomem *port, u8 *buf, unsigned int len)
+static inline void raw_rom_insb(const volatile u8 __iomem *port, u8 *buf,
+				unsigned int len)
 {
 	unsigned int i;
 
@@ -430,7 +432,7 @@ static inline void raw_rom_outsb(volatile u8 __iomem *port, const u8 *buf,
 		rom_out_8(port, *buf++);
 }
 
-static inline void raw_rom_insw(volatile u16 __iomem *port, u16 *buf,
+static inline void raw_rom_insw(const volatile u16 __iomem *port, u16 *buf,
 				   unsigned int nr)
 {
 	unsigned int i;
@@ -448,7 +450,7 @@ static inline void raw_rom_outsw(volatile u16 __iomem *port, const u16 *buf,
 		rom_out_be16(port, *buf++);
 }
 
-static inline void raw_rom_insw_swapw(volatile u16 __iomem *port, u16 *buf,
+static inline void raw_rom_insw_swapw(const volatile u16 __iomem *port, u16 *buf,
 				   unsigned int nr)
 {
 	unsigned int i;
-- 
2.39.2

Re: [PATCH] m68k: asm/io.h: mark mmio read addresses as const

[Geert Uytterhoeven]

Hi Arnd,

On Mon, Sep 25, 2023 at 5:53 PM Arnd Bergmann <arnd@kernel.org> wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> 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@intel.com/
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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@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

Re: [PATCH] m68k: asm/io.h: mark mmio read addresses as const

[Arnd Bergmann]

On Mon, Oct 2, 2023, at 15:12, Geert Uytterhoeven wrote:
> On Mon, Sep 25, 2023 at 5:53 PM Arnd Bergmann <arnd@kernel.org> wrote:
>>  #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}()?

Right, these seem to have escaped my regex searches.

> I can do that while applying...

Ok, thanks!

     Arnd

Re: [PATCH] m68k: asm/io.h: mark mmio read addresses as const

[Geert Uytterhoeven]

On Mon, Oct 2, 2023 at 9:42 PM Arnd Bergmann <arnd@kernel.org> wrote:
> On Mon, Oct 2, 2023, at 15:12, Geert Uytterhoeven wrote:
> > On Mon, Sep 25, 2023 at 5:53 PM Arnd Bergmann <arnd@kernel.org> wrote:
> >>  #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}()?
>
> Right, these seem to have escaped my regex searches.
>
> > I can do that while applying...
>
> Ok, thanks!

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
i.e. will queue in the m68k for-v6.7 branch.

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