On Fri, 11 Mar 2022 09:44:11 +0800 kernel test robot <lkp@xxxxxxxxx> wrote: > Hi Ard, > > FYI, the error/warning still remains. > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > head: 71941773e143369a73c9c4a3b62fbb60736a1182 > commit: 41918ec82eb6f80c8b401422f27ca76c85aa0cb7 [4103/11953] ARM: ftrace: enable the graph tracer with the EABI unwinder > config: arm-aspeed_g4_defconfig (https://download.01.org/0day-ci/archive/20220311/202203110903.3xDyTUVl-lkp@xxxxxxxxx/config) > compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 276ca87382b8f16a65bddac700202924228982f6) > 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/next/linux-next.git/commit/?id=41918ec82eb6f80c8b401422f27ca76c85aa0cb7 > git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > git fetch --no-tags linux-next master > git checkout 41918ec82eb6f80c8b401422f27ca76c85aa0cb7 > # 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=arm SHELL=/bin/bash arch/arm/kernel/ > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > All warnings (new ones prefixed by >>): > > >> arch/arm/kernel/ftrace.c:229:6: warning: no previous prototype for function 'prepare_ftrace_return' [-Wmissing-prototypes] > void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, > ^ > arch/arm/kernel/ftrace.c:229:1: note: declare 'static' if the function is not intended to be used outside of this translation unit > void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, > ^ > static > 1 warning generated. > Hmm, this is only called from assembly code, which doesn't care about prototypes. Is there a way to quiet this warning to say "this is called only by assembly"? Or do we just add a useless prototype to shut it up? -- Steve > > vim +/prepare_ftrace_return +229 arch/arm/kernel/ftrace.c > > 376cfa8730c08c Tim Bird 2010-10-09 226 > 376cfa8730c08c Tim Bird 2010-10-09 227 #ifdef CONFIG_FUNCTION_GRAPH_TRACER > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 228 asmlinkage > 376cfa8730c08c Tim Bird 2010-10-09 @229 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 230 unsigned long frame_pointer, > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 231 unsigned long stack_pointer) > 376cfa8730c08c Tim Bird 2010-10-09 232 { > 376cfa8730c08c Tim Bird 2010-10-09 233 unsigned long return_hooker = (unsigned long) &return_to_handler; > 376cfa8730c08c Tim Bird 2010-10-09 234 unsigned long old; > 376cfa8730c08c Tim Bird 2010-10-09 235 > 376cfa8730c08c Tim Bird 2010-10-09 236 if (unlikely(atomic_read(¤t->tracing_graph_pause))) > 376cfa8730c08c Tim Bird 2010-10-09 237 return; > 376cfa8730c08c Tim Bird 2010-10-09 238 > 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 239 if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER)) { > 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 240 /* FP points one word below parent's top of stack */ > 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 241 frame_pointer += 4; > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 242 } else { > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 243 struct stackframe frame = { > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 244 .fp = frame_pointer, > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 245 .sp = stack_pointer, > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 246 .lr = self_addr, > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 247 .pc = self_addr, > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 248 }; > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 249 if (unwind_frame(&frame) < 0) > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 250 return; > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 251 if (frame.lr != self_addr) > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 252 parent = frame.lr_addr; > 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 253 frame_pointer = frame.sp; > 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 254 } > 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 255 > 376cfa8730c08c Tim Bird 2010-10-09 256 old = *parent; > 376cfa8730c08c Tim Bird 2010-10-09 257 *parent = return_hooker; > 376cfa8730c08c Tim Bird 2010-10-09 258 > f1f5b14afd7cce Steven Rostedt (VMware 2018-11-18 259) if (function_graph_enter(old, self_addr, frame_pointer, NULL)) > 376cfa8730c08c Tim Bird 2010-10-09 260 *parent = old; > 376cfa8730c08c Tim Bird 2010-10-09 261 } > dd686eb13959e4 Rabin Vincent 2010-11-06 262 > > :::::: The code at line 229 was first introduced by commit > :::::: 376cfa8730c08c0394d0aa1d4a80fd8c9971f323 ARM: ftrace: function graph tracer support > > :::::: TO: Tim Bird <tim.bird@xxxxxxxxxxx> > :::::: CC: Rabin Vincent <rabin@xxxxxx> > > --- > 0-DAY CI Kernel Test Service > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
