[tip:x86/urgent 5/5] arch/x86/lib/iomem.c:66:28: sparse: sparse: dereference of noderef expression

[tip:x86/urgent 5/5] arch/x86/lib/iomem.c:66:28: sparse: sparse: dereference of noderef expression

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/urgent
head:   fb96320e194066cd9a177989920e8854fa6c1537
commit: fb96320e194066cd9a177989920e8854fa6c1537 [5/5] x86/sev: Unroll string mmio with CC_ATTR_GUEST_UNROLL_STRING_IO
config: i386-randconfig-s002 (https://download.01.org/0day-ci/archive/20220325/202203250750.ghDxLnaB-lkp@intel.com/config)
compiler: gcc-9 (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=fb96320e194066cd9a177989920e8854fa6c1537
        git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
        git fetch --no-tags tip x86/urgent
        git checkout fb96320e194066cd9a177989920e8854fa6c1537
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)
   arch/x86/lib/iomem.c:39:23: sparse: sparse: cast removes address space '__iomem' of expression
   arch/x86/lib/iomem.c:56:19: sparse: sparse: cast removes address space '__iomem' of expression
   arch/x86/lib/iomem.c:115:25: sparse: sparse: cast removes address space '__iomem' of expression
>> arch/x86/lib/iomem.c:66:28: sparse: sparse: dereference of noderef expression
   arch/x86/lib/iomem.c:76:20: sparse: sparse: dereference of noderef expression
   arch/x86/lib/iomem.c:85:20: sparse: sparse: dereference of noderef expression

vim +66 arch/x86/lib/iomem.c

    58	
    59	static void unrolled_memcpy_fromio(void *to, const volatile void __iomem *from, size_t n)
    60	{
    61		const volatile char __iomem *in = from;
    62		char *out = to;
    63		int i;
    64	
    65		for (i = 0; i < n; ++i)
  > 66			out[i] = in[i];
    67	}
    68	

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