Subject: Re: [PATCH 3/3] powerpc: Fix pre-update addressing in inline assembly

From: kernel test robot <[email-masked]>
Date: Mon, 19 Oct 2020 23:35:09 +0800

Hi Christophe,

I love your patch! Yet something to improve:

[auto build test ERROR on powerpc/next]
[also build test ERROR on linus/master next-20201016]
[cannot apply to kvm-ppc/kvm-ppc-next mpe/next v5.9]
[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]

url:    https://github.com/0day-ci/linux/commits/Christophe-Leroy/powerpc-uaccess-Don-t-use-m-constraint-with-GCC-4-9/20201019-201504
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc64-randconfig-r012-20201019 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 094e9f4779eb9b5c6a49014f2f80b8cbb833572f)
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 powerpc64 cross compiling tool for clang build
        # apt-get install binutils-powerpc64-linux-gnu
        # https://github.com/0day-ci/linux/commit/d57fd8d270993414b8c0414d7be4b03cc3de1856
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Christophe-Leroy/powerpc-uaccess-Don-t-use-m-constraint-with-GCC-4-9/20201019-201504
        git checkout d57fd8d270993414b8c0414d7be4b03cc3de1856
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email-masked]>

All errors (new ones prefixed by >>):

   In file included from arch/powerpc/kernel/asm-offsets.c:14:
   In file included from include/linux/compat.h:14:
   In file included from include/linux/sem.h:5:
   In file included from include/uapi/linux/sem.h:5:
   In file included from include/linux/ipc.h:5:
   In file included from include/linux/spinlock.h:51:
   In file included from include/linux/preempt.h:78:
   In file included from ./arch/powerpc/include/generated/asm/preempt.h:1:
   In file included from include/asm-generic/preempt.h:5:
   In file included from include/linux/thread_info.h:21:
   In file included from arch/powerpc/include/asm/current.h:13:
   In file included from arch/powerpc/include/asm/paca.h:31:
   In file included from arch/powerpc/include/asm/atomic.h:13:
   In file included from arch/powerpc/include/asm/ppc_asm.h:9:
   In file included from arch/powerpc/include/asm/processor.h:40:
>> arch/powerpc/include/asm/ptrace.h:288:20: error: use of undeclared identifier 'THREAD_SIZE'
           return ((addr & ~(THREAD_SIZE - 1))  ==
                             ^
   arch/powerpc/include/asm/ptrace.h:289:35: error: use of undeclared identifier 'THREAD_SIZE'
                   (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
                                                   ^
   In file included from arch/powerpc/kernel/asm-offsets.c:21:
   include/linux/mman.h:137:9: warning: division by zero is undefined [-Wdivision-by-zero]
                  _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    ) |
                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/mman.h:115:21: note: expanded from macro '_calc_vm_trans'
      : ((x) & (bit1)) / ((bit1) / (bit2))))
                       ^ ~~~~~~~~~~~~~~~~~
   include/linux/mman.h:138:9: warning: division by zero is undefined [-Wdivision-by-zero]
                  _calc_vm_trans(flags, MAP_SYNC,       VM_SYNC      );
                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/mman.h:115:21: note: expanded from macro '_calc_vm_trans'
      : ((x) & (bit1)) / ((bit1) / (bit2))))
                       ^ ~~~~~~~~~~~~~~~~~
   2 warnings and 2 errors generated.
   make[2]: *** [scripts/Makefile.build:117: arch/powerpc/kernel/asm-offsets.s] Error 1
   make[2]: Target '__build' not remade because of errors.
   make[1]: *** [Makefile:1202: prepare0] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:185: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.

vim +/THREAD_SIZE +288 arch/powerpc/include/asm/ptrace.h

359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  275  
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  276  /**
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  277   * regs_within_kernel_stack() - check the address in the stack
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  278   * @regs:      pt_regs which contains kernel stack pointer.
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  279   * @addr:      address which is checked.
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  280   *
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  281   * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  282   * If @addr is within the kernel stack, it returns true. If not, returns false.
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  283   */
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  284  
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  285  static inline bool regs_within_kernel_stack(struct pt_regs *regs,
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  286  						unsigned long addr)
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  287  {
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07 @288  	return ((addr & ~(THREAD_SIZE - 1))  ==
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  289  		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  290  }
359e4284a3f37ab Mahesh Salgaonkar 2010-04-07  291  

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