Re: [PATCH] tracing: Use linker magic instead of recasting ftrace_ops_list_func()

[kernel test robot <lkp@intel.com>]

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Hi Steven,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linux/master]
[also build test WARNING on tip/perf/core linus/master v5.8-rc1 next-20200618]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use  as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Steven-Rostedt/tracing-Use-linker-magic-instead-of-recasting-ftrace_ops_list_func/20200618-045733
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git a5dc8300df75e8b8384b4c82225f1e4a0b4d9b55
config: x86_64-randconfig-a015-20200618 (attached as .config)
compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project 487ca07fcc75d52755c9fe2ee05bcb3b6eeeec44)
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 x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>, old ones prefixed by <<):

kernel/trace/ftrace.c:300:5: warning: no previous prototype for function '__register_ftrace_function' [-Wmissing-prototypes]
int __register_ftrace_function(struct ftrace_ops *ops)
^
kernel/trace/ftrace.c:300:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int __register_ftrace_function(struct ftrace_ops *ops)
^
static
kernel/trace/ftrace.c:343:5: warning: no previous prototype for function '__unregister_ftrace_function' [-Wmissing-prototypes]
int __unregister_ftrace_function(struct ftrace_ops *ops)
^
kernel/trace/ftrace.c:343:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int __unregister_ftrace_function(struct ftrace_ops *ops)
^
static
kernel/trace/ftrace.c:582:5: warning: no previous prototype for function 'ftrace_profile_pages_init' [-Wmissing-prototypes]
int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
^
kernel/trace/ftrace.c:582:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
^
static
kernel/trace/ftrace.c:3796:15: warning: no previous prototype for function 'arch_ftrace_match_adjust' [-Wmissing-prototypes]
char * __weak arch_ftrace_match_adjust(char *str, const char *search)
^
kernel/trace/ftrace.c:3796:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
char * __weak arch_ftrace_match_adjust(char *str, const char *search)
^
static
>> kernel/trace/ftrace.c:6854:6: warning: no previous prototype for function 'arch_ftrace_ops_list_func' [-Wmissing-prototypes]
void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
^
kernel/trace/ftrace.c:6854:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
^
static
5 warnings generated.

vim +/arch_ftrace_ops_list_func +6854 kernel/trace/ftrace.c

  6836	
  6837	/*
  6838	 * Some archs only support passing ip and parent_ip. Even though
  6839	 * the list function ignores the op parameter, we do not want any
  6840	 * C side effects, where a function is called without the caller
  6841	 * sending a third parameter.
  6842	 * Archs are to support both the regs and ftrace_ops at the same time.
  6843	 * If they support ftrace_ops, it is assumed they support regs.
  6844	 * If call backs want to use regs, they must either check for regs
  6845	 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
  6846	 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
  6847	 * An architecture can pass partial regs with ftrace_ops and still
  6848	 * set the ARCH_SUPPORTS_FTRACE_OPS.
  6849	 *
  6850	 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
  6851	 * arch_ftrace_ops_list_func.
  6852	 */
  6853	#if ARCH_SUPPORTS_FTRACE_OPS
> 6854	void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
  6855				       struct ftrace_ops *op, struct pt_regs *regs)
  6856	{
  6857		__ftrace_ops_list_func(ip, parent_ip, NULL, regs);
  6858	}
  6859	#else
  6860	void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
  6861	{
  6862		__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
  6863	}
  6864	#endif
  6865	NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
  6866	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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