linux-kernel - arch/powerpc/platforms/microwatt/smp.c:79:24: sparse: sparse: cast removes address space '_

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Message-ID: <202601271250.ASHv58o3-lkp@intel.com>
Date: Tue, 27 Jan 2026 12:56:27 +0800
From: kernel test robot <lkp@...el.com>
To: Paul Mackerras <paulus@...abs.org>
Cc: oe-kbuild-all@...ts.linux.dev, linux-kernel@...r.kernel.org,
 Madhavan Srinivasan <maddy@...ux.ibm.com>
Subject: arch/powerpc/platforms/microwatt/smp.c:79:24: sparse:
 sparse: cast removes address space '__iomem' of expression

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   fcb70a56f4d81450114034b2c61f48ce7444a0e2
commit: aca95fb6bb572a77f39d42d83ab72a965026577d powerpc/microwatt: Add SMP support
date:   11 months ago
config: powerpc64-randconfig-r123-20260126 (https://download.01.org/0day-ci/archive/20260127/202601271250.ASHv58o3-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 9b8addffa70cee5b2acc5454712d9cf78ce45710)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260127/202601271250.ASHv58o3-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@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202601271250.ASHv58o3-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> arch/powerpc/platforms/microwatt/smp.c:79:24: sparse: sparse: cast removes address space '__iomem' of expression
>> arch/powerpc/platforms/microwatt/smp.c:79:24: sparse: sparse: incorrect type in argument 1 (different address spaces) @@     expected void [noderef] __iomem *addr @@     got void * @@
   arch/powerpc/platforms/microwatt/smp.c:79:24: sparse:     expected void [noderef] __iomem *addr
   arch/powerpc/platforms/microwatt/smp.c:79:24: sparse:     got void *

vim +/__iomem +79 arch/powerpc/platforms/microwatt/smp.c

    42	
    43	void __init microwatt_init_smp(void)
    44	{
    45		volatile unsigned char __iomem *syscon;
    46		int ncpus;
    47		int timeout;
    48	
    49		syscon = early_ioremap(SYSCON_BASE, SYSCON_LENGTH);
    50		if (syscon == NULL) {
    51			pr_err("Failed to map SYSCON\n");
    52			return;
    53		}
    54		ncpus = (readl(syscon + SYSCON_CPU_CTRL) >> 8) & 0xff;
    55		if (ncpus < 2)
    56			goto out;
    57	
    58		smp_ops = &microwatt_smp_ops;
    59	
    60		/*
    61		 * Write two instructions at location 0:
    62		 * mfspr r3, PIR
    63		 * b __secondary_hold
    64		 */
    65		*(unsigned int *)KERNELBASE = PPC_RAW_MFSPR(3, SPRN_PIR);
    66		*(unsigned int *)(KERNELBASE+4) = PPC_RAW_BRANCH(&__secondary_hold - (char *)(KERNELBASE+4));
    67	
    68		/* enable the other CPUs, they start at location 0 */
    69		writel((1ul << ncpus) - 1, syscon + SYSCON_CPU_CTRL);
    70	
    71		timeout = 10000;
    72		while (!__secondary_hold_acknowledge) {
    73			if (--timeout == 0)
    74				break;
    75			barrier();
    76		}
    77	
    78	 out:
  > 79		early_iounmap((void *)syscon, SYSCON_LENGTH);

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki