Re: [PATCH] LoongArch: Add perf events support

[kernel test robot]

Hi Huacai,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.0-rc1 next-20220816]
[cannot apply to soc/for-next]
[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/Huacai-Chen/LoongArch-Add-perf-events-support/20220815-204852
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 568035b01cfb107af8d2e4bd2fb9aea22cf5b868
config: loongarch-randconfig-s051-20220815 (https://download.01.org/0day-ci/archive/20220816/202208161648.zq48ilEV-lkp@xxxxxxxxx/config)
compiler: loongarch64-linux-gcc (GCC) 12.1.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-39-gce1a6720-dirty
        # https://github.com/intel-lab-lkp/linux/commit/0e6d9490ff3f6129799675b9288135022a0908e2
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Huacai-Chen/LoongArch-Add-perf-events-support/20220815-204852
        git checkout 0e6d9490ff3f6129799675b9288135022a0908e2
        # save the config file
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=loongarch 

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>

sparse warnings: (new ones prefixed by >>)
>> arch/loongarch/kernel/perf_event.c:30:50: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected unsigned long [noderef] __user *user_frame_tail @@     got unsigned long * @@
   arch/loongarch/kernel/perf_event.c:30:50: sparse:     expected unsigned long [noderef] __user *user_frame_tail
   arch/loongarch/kernel/perf_event.c:30:50: sparse:     got unsigned long *
   arch/loongarch/kernel/perf_event.c: note: in included file (through arch/loongarch/include/asm/cpu-info.h, arch/loongarch/include/asm/processor.h, ...):
   arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: undefined identifier '__builtin_loongarch_csrrd_d'
   arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: undefined identifier '__builtin_loongarch_csrwr_d'
   arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:237:16: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type
   arch/loongarch/include/asm/loongarch.h:247:9: sparse: sparse: cast from unknown type

vim +30 arch/loongarch/kernel/perf_event.c

    20	
    21	/*
    22	 * Get the return address for a single stackframe and return a pointer to the
    23	 * next frame tail.
    24	 */
    25	static unsigned long
    26	user_backtrace(struct perf_callchain_entry_ctx *entry, unsigned long fp)
    27	{
    28		struct stack_frame buftail;
    29		unsigned long err;
  > 30		unsigned long __user *user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
    31	
    32		/* Also check accessibility of one struct frame_tail beyond */
    33		if (!access_ok(user_frame_tail, sizeof(buftail)))
    34			return 0;
    35	
    36		pagefault_disable();
    37		err = __copy_from_user_inatomic(&buftail, user_frame_tail, sizeof(buftail));
    38		pagefault_enable();
    39	
    40		if (err || (unsigned long)user_frame_tail >= buftail.fp)
    41			return 0;
    42	
    43		perf_callchain_store(entry, buftail.ra);
    44	
    45		return buftail.fp;
    46	}
    47	

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