Re: [PATCH RFC 2/4] asm-generic/io.h: add io{read,write}128 accessors

[kernel test robot <lkp@intel.com>]

Hi Chenghai,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on arnd-asm-generic/master]
[also build test WARNING on arm64/for-next/core soc/for-next linus/master v6.18-rc5 next-20251111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Chenghai-Huang/UAPI-Introduce-128-bit-types-and-byteswap-operations/20251112-100133
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git master
patch link:    https://lore.kernel.org/r/20251112015846.1842207-3-huangchenghai2%40huawei.com
patch subject: [PATCH RFC 2/4] asm-generic/io.h: add io{read,write}128 accessors
config: riscv-allnoconfig (https://download.01.org/0day-ci/archive/20251112/202511121203.2yAbgprF-lkp@intel.com/config)
compiler: riscv64-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251112/202511121203.2yAbgprF-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511121203.2yAbgprF-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/byteorder/little_endian.h:5,
                    from arch/riscv/include/uapi/asm/byteorder.h:10,
                    from include/asm-generic/bitops/le.h:6,
                    from arch/riscv/include/asm/bitops.h:376,
                    from include/linux/bitops.h:67,
                    from include/linux/thread_info.h:27,
                    from include/asm-generic/preempt.h:5,
                    from ./arch/riscv/include/generated/asm/preempt.h:1,
                    from include/linux/preempt.h:79,
                    from include/linux/spinlock.h:56,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:7,
                    from include/linux/mm.h:7,
                    from arch/riscv/kernel/asm-offsets.c:8:
   include/asm-generic/io.h: In function 'ioread128':
>> include/asm-generic/io.h:948:61: warning: passing argument 1 of '__raw_read128' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     948 |         val = __le128_to_cpu((__le128 __force)__raw_read128(addr));
         |                                                             ^~~~
   include/uapi/linux/byteorder/little_endian.h:35:54: note: in definition of macro '__le128_to_cpu'
      35 | #define __le128_to_cpu(x) ((__force __u128)(__le128)(x))
         |                                                      ^
   In file included from arch/riscv/include/asm/io.h:136,
                    from include/linux/io.h:12,
                    from include/linux/irq.h:20,
                    from include/asm-generic/hardirq.h:17,
                    from ./arch/riscv/include/generated/asm/hardirq.h:1,
                    from include/linux/hardirq.h:11,
                    from include/linux/interrupt.h:11,
                    from include/linux/trace_recursion.h:5,
                    from include/linux/ftrace.h:10,
                    from arch/riscv/kernel/asm-offsets.c:10:
   include/asm-generic/io.h:152:57: note: expected 'volatile void *' but argument is of type 'const volatile void *'
     152 | static inline u128 __raw_read128(volatile void __iomem *addr)
         |                                  ~~~~~~~~~~~~~~~~~~~~~~~^~~~
--
   In file included from include/linux/byteorder/little_endian.h:5,
                    from arch/riscv/include/uapi/asm/byteorder.h:10,
                    from include/asm-generic/bitops/le.h:6,
                    from arch/riscv/include/asm/bitops.h:376,
                    from include/linux/bitops.h:67,
                    from include/linux/thread_info.h:27,
                    from include/asm-generic/preempt.h:5,
                    from ./arch/riscv/include/generated/asm/preempt.h:1,
                    from include/linux/preempt.h:79,
                    from include/linux/spinlock.h:56,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:7,
                    from include/linux/mm.h:7,
                    from arch/riscv/kernel/asm-offsets.c:8:
   include/asm-generic/io.h: In function 'ioread128':
>> include/asm-generic/io.h:948:61: warning: passing argument 1 of '__raw_read128' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     948 |         val = __le128_to_cpu((__le128 __force)__raw_read128(addr));
         |                                                             ^~~~
   include/uapi/linux/byteorder/little_endian.h:35:54: note: in definition of macro '__le128_to_cpu'
      35 | #define __le128_to_cpu(x) ((__force __u128)(__le128)(x))
         |                                                      ^
   In file included from arch/riscv/include/asm/io.h:136,
                    from include/linux/io.h:12,
                    from include/linux/irq.h:20,
                    from include/asm-generic/hardirq.h:17,
                    from ./arch/riscv/include/generated/asm/hardirq.h:1,
                    from include/linux/hardirq.h:11,
                    from include/linux/interrupt.h:11,
                    from include/linux/trace_recursion.h:5,
                    from include/linux/ftrace.h:10,
                    from arch/riscv/kernel/asm-offsets.c:10:
   include/asm-generic/io.h:152:57: note: expected 'volatile void *' but argument is of type 'const volatile void *'
     152 | static inline u128 __raw_read128(volatile void __iomem *addr)
         |                                  ~~~~~~~~~~~~~~~~~~~~~~~^~~~


vim +948 include/asm-generic/io.h

   939	
   940	#ifdef CONFIG_ARCH_SUPPORTS_INT128
   941	#ifndef ioread128
   942	#define ioread128 ioread128
   943	static inline u128 ioread128(const volatile void __iomem *addr)
   944	{
   945		u128 val;
   946	
   947		__io_br();
 > 948		val = __le128_to_cpu((__le128 __force)__raw_read128(addr));
   949		__io_ar(val);
   950	
   951		return val;
   952	}
   953	#endif
   954	#endif /* CONFIG_ARCH_SUPPORTS_INT128 */
   955	

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