[arm-integrator:kernel-in-vmalloc-v6.2-rc3-just-ttbr0-split 30/30] arch/arm/include/asm/uaccess.h:54:14: error: call to undeclared function 'current_user_ttbr'; ISO C99 and later do not support implicit function declarations

[arm-integrator:kernel-in-vmalloc-v6.2-rc3-just-ttbr0-split 30/30] arch/arm/include/asm/uaccess.h:54:14: error: call to undeclared function 'current_user_ttbr'; ISO C99 and later do not support implicit function declarations

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git kernel-in-vmalloc-v6.2-rc3-just-ttbr0-split
head:   8c7a9ba4d5ab142c56f970395de2c419dbcd0a72
commit: 8c7a9ba4d5ab142c56f970395de2c419dbcd0a72 [30/30] switch PGD/TTBR0 in <asm/uaccess-asm.h>
config: arm-randconfig-r046-20230312 (https://download.01.org/0day-ci/archive/20230314/202303142222.QT4VREFq-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git/commit/?id=8c7a9ba4d5ab142c56f970395de2c419dbcd0a72
        git remote add arm-integrator https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator.git
        git fetch --no-tags arm-integrator kernel-in-vmalloc-v6.2-rc3-just-ttbr0-split
        git checkout 8c7a9ba4d5ab142c56f970395de2c419dbcd0a72
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm prepare

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303142222.QT4VREFq-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:29:
   In file included from include/linux/pgtable.h:6:
   In file included from arch/arm/include/asm/pgtable.h:25:
   arch/arm/include/asm/pgtable-nommu.h:49:9: warning: 'ZERO_PAGE' macro redefined [-Wmacro-redefined]
   #define ZERO_PAGE(vaddr)        (virt_to_page((const void *)0))
           ^
   arch/arm/include/asm/pgtable.h:19:9: note: previous definition is here
   #define ZERO_PAGE(vaddr)        (empty_zero_page)
           ^
   In file included from arch/arm/kernel/asm-offsets.c:12:
   In file included from include/linux/mm.h:740:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:9:
   In file included from include/linux/sched/task.h:11:
   In file included from include/linux/uaccess.h:11:
>> arch/arm/include/asm/uaccess.h:54:14: error: call to undeclared function 'current_user_ttbr'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
           user_ttbr = current_user_ttbr();
                       ^
>> arch/arm/include/asm/uaccess.h:55:16: error: call to undeclared function 'read_sysreg'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
           kernel_ttbr = read_sysreg(TTBR1);
                         ^
>> arch/arm/include/asm/uaccess.h:55:28: error: use of undeclared identifier 'TTBR1'
           kernel_ttbr = read_sysreg(TTBR1);
                                     ^
>> arch/arm/include/asm/uaccess.h:56:2: error: call to undeclared function 'write_sysreg'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
           write_sysreg(user_ttbr, TTBR0);
           ^
>> arch/arm/include/asm/uaccess.h:56:26: error: use of undeclared identifier 'TTBR0'
           write_sysreg(user_ttbr, TTBR0);
                                   ^
   arch/arm/include/asm/uaccess.h:69:2: error: call to undeclared function 'write_sysreg'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
           write_sysreg(flags, TTBR0);
           ^
   arch/arm/include/asm/uaccess.h:69:22: error: use of undeclared identifier 'TTBR0'
           write_sysreg(flags, TTBR0);
                               ^
   1 warning and 7 errors generated.
   make[2]: *** [scripts/Makefile.build:114: arch/arm/kernel/asm-offsets.s] Error 1
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:1286: prepare0] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:242: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.


vim +/current_user_ttbr +54 arch/arm/include/asm/uaccess.h

    28	
    29	/*
    30	 * These two functions allow hooking accesses to userspace to increase
    31	 * system integrity by ensuring that the kernel can not inadvertantly
    32	 * perform such accesses (eg, via list poison values) which could then
    33	 * be exploited for priviledge escalation.
    34	 */
    35	static __always_inline unsigned int uaccess_save_and_enable(void)
    36	{
    37	#ifdef CONFIG_CPU_SW_DOMAIN_PAN
    38		unsigned int old_domain = get_domain();
    39	
    40		/* Set the current domain access to permit user accesses */
    41		set_domain((old_domain & ~domain_mask(DOMAIN_USER)) |
    42			   domain_val(DOMAIN_USER, DOMAIN_CLIENT));
    43	
    44		return old_domain;
    45	#else
    46		/*
    47		 * Intended semantics: switch to the userspace MM context (enable
    48		 * userspace), then return (save) the previous kernelspace TTBR0
    49		 * value.
    50		 */
    51		/* FIXME: ifdef CONFIG_VMSPLIT_4G_4G */
    52		u64 user_ttbr, kernel_ttbr;
    53	
  > 54		user_ttbr = current_user_ttbr();
  > 55		kernel_ttbr = read_sysreg(TTBR1);
  > 56		write_sysreg(user_ttbr, TTBR0);
    57	
    58		return kernel_ttbr;
    59	#endif
    60	}
    61	

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https://github.com/intel/lkp-tests