Christophe Leroy <christophe.le...@csgroup.eu> writes: > Le 29/11/2021 à 23:55, kernel test robot a écrit : >> Hi Christophe, >> >> I love your patch! Perhaps something to improve: >> >> [auto build test WARNING on powerpc/next] >> [also build test WARNING on v5.16-rc3 next-20211129] >> [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-inst-Refactor-___get_user_instr/20211130-015346 >> base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git >> next >> config: powerpc-randconfig-r023-20211129 >> (https://download.01.org/0day-ci/archive/20211130/202111300652.0ydbnvyj-...@intel.com/config) >> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project >> df08b2fe8b35cb63dfb3b49738a3494b9b4e6f8e) >> 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 powerpc cross compiling tool for clang build >> # apt-get install binutils-powerpc-linux-gnu >> # >> https://github.com/0day-ci/linux/commit/fb7bff30cc0efc7e4df1b48bb69de1f325eee826 >> git remote add linux-review https://github.com/0day-ci/linux >> git fetch --no-tags linux-review >> Christophe-Leroy/powerpc-inst-Refactor-___get_user_instr/20211130-015346 >> git checkout fb7bff30cc0efc7e4df1b48bb69de1f325eee826 >> # save the config file to linux build tree >> mkdir build_dir >> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 >> O=build_dir ARCH=powerpc prepare >> >> If you fix the issue, kindly add following tag as appropriate >> Reported-by: kernel test robot <l...@intel.com> >> >> All warnings (new ones prefixed by >>): >> >> In file included from arch/powerpc/kernel/asm-offsets.c:71: >> In file included from arch/powerpc/kernel/../xmon/xmon_bpts.h:7: >>>> arch/powerpc/include/asm/inst.h:165:20: warning: variable 'val' is >>>> uninitialized when used here [-Wuninitialized] >> *inst = ppc_inst(val); >> ^~~ >> arch/powerpc/include/asm/inst.h:53:22: note: expanded from macro >> 'ppc_inst' >> #define ppc_inst(x) (x) >> ^ >> arch/powerpc/include/asm/inst.h:155:18: note: initialize the variable >> 'val' to silence this warning >> unsigned int val, suffix; >> ^ >> = 0 > > I can't understand what's wrong here. > > We have > > __get_kernel_nofault(&val, src, u32, Efault); > if (IS_ENABLED(CONFIG_PPC64) && get_op(val) == OP_PREFIX) { > __get_kernel_nofault(&suffix, src + 1, u32, Efault); > *inst = ppc_inst_prefix(val, suffix); > } else { > *inst = ppc_inst(val); > } > > With > > #define __get_kernel_nofault(dst, src, type, err_label) > \ > __get_user_size_goto(*((type *)(dst)), \ > (__force type __user *)(src), sizeof(type), err_label) > > > And > > #define __get_user_size_goto(x, ptr, size, label) > \ > do { > \ > BUILD_BUG_ON(size > sizeof(x)); > \ > switch (size) { > \ > case 1: __get_user_asm_goto(x, (u8 __user *)ptr, label, "lbz"); break; > \ > case 2: __get_user_asm_goto(x, (u16 __user *)ptr, label, "lhz"); break; > \ > case 4: __get_user_asm_goto(x, (u32 __user *)ptr, label, "lwz"); break; > \ > case 8: __get_user_asm2_goto(x, (u64 __user *)ptr, label); break; > \ > default: x = 0; BUILD_BUG(); > \ > } > \ > } while (0) > > And > > #define __get_user_asm_goto(x, addr, label, op) \ > asm_volatile_goto( \ > "1: "op"%U1%X1 %0, %1 # get_user\n" \ > EX_TABLE(1b, %l2) \ > : "=r" (x) \ > : "m<>" (*addr) \ > : \ > : label) > > > I see no possibility, no alternative path where val wouldn't be set. The > asm clearly has *addr as an output param so it is always set.
I guess clang can't convince itself of that? >> 1 warning generated. >> <stdin>:1559:2: warning: syscall futex_waitv not implemented >> [-W#warnings] >> #warning syscall futex_waitv not implemented >> ^ >> 1 warning generated. >> arch/powerpc/kernel/vdso32/gettimeofday.S:72:8: error: unsupported >> directive '.stabs' >> .stabs "_restgpr_31_x:F-1",36,0,0,_restgpr_31_x; .globl _restgpr_31_x; >> _restgpr_31_x: >> ^ >> arch/powerpc/kernel/vdso32/gettimeofday.S:73:8: error: unsupported >> directive '.stabs' >> .stabs "_rest32gpr_31_x:F-1",36,0,0,_rest32gpr_31_x; .globl >> _rest32gpr_31_x; _rest32gpr_31_x: > > How should we fix that ? Will clang support .stabs in the future ? I think we should drop any stabs annotations / support. AFAICT none of the toolchains we support produce it anymore. cheers
