Hi Mark,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git arm64/ftrace/minimal-regs
head:   1e840c7ba731d3b9fe5d23a41b3744fa8999ec1e
commit: cfc377737ee03317682a153342d7f30427204591 [2/5] ftrace: pass fregs to arch_ftrace_set_direct_caller()
config: x86_64-rhel-8.3-kselftests
compiler: gcc-11 (Debian 11.3.0-5) 11.3.0
reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/commit/?id=cfc377737ee03317682a153342d7f30427204591
        git remote add mark https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git
        git fetch --no-tags mark arm64/ftrace/minimal-regs
        git checkout cfc377737ee03317682a153342d7f30427204591
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 prepare

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

All errors (new ones prefixed by >>):

   In file included from include/linux/ftrace.h:23,
                    from include/linux/kvm_host.h:32,
                    from arch/x86/kernel/../kvm/vmx/vmx.h:5,
                    from arch/x86/kernel/asm-offsets.c:22:
   arch/x86/include/asm/ftrace.h:45:57: warning: 'struct ftrace_regs' declared inside parameter list will not be visible outside of this definition or declaration
      45 | static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr)
         |                                                         ^~~~~~~~~~~
   arch/x86/include/asm/ftrace.h: In function 'arch_ftrace_set_direct_caller':
>> arch/x86/include/asm/ftrace.h:47:32: error: implicit declaration of function 'ftrace_get_regs' [-Werror=implicit-function-declaration]
      47 |         struct pt_regs *regs = ftrace_get_regs(fregs);
         |                                ^~~~~~~~~~~~~~~
   arch/x86/include/asm/ftrace.h:47:32: warning: initialization of 'struct pt_regs *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
   In file included from include/linux/kvm_host.h:32,
                    from arch/x86/kernel/../kvm/vmx/vmx.h:5,
                    from arch/x86/kernel/asm-offsets.c:22:
   include/linux/ftrace.h: At top level:
>> include/linux/ftrace.h:121:40: error: conflicting types for 'ftrace_get_regs'; have 'struct pt_regs *(struct ftrace_regs *)'
     121 | static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs)
         |                                        ^~~~~~~~~~~~~~~
   In file included from include/linux/ftrace.h:23,
                    from include/linux/kvm_host.h:32,
                    from arch/x86/kernel/../kvm/vmx/vmx.h:5,
                    from arch/x86/kernel/asm-offsets.c:22:
   arch/x86/include/asm/ftrace.h:47:32: note: previous implicit declaration of 'ftrace_get_regs' with type 'int()'
      47 |         struct pt_regs *regs = ftrace_get_regs(fregs);
         |                                ^~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors
   make[2]: *** [scripts/Makefile.build:117: arch/x86/kernel/asm-offsets.s] Error 1
   make[2]: Target '__build' not remade because of errors.
   make[1]: *** [Makefile:1205: prepare0] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:222: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.


vim +/ftrace_get_regs +47 arch/x86/include/asm/ftrace.h

    37	
    38	/*
    39	 * When a ftrace registered caller is tracing a function that is
    40	 * also set by a register_ftrace_direct() call, it needs to be
    41	 * differentiated in the ftrace_caller trampoline. To do this, we
    42	 * place the direct caller in the ORIG_AX part of pt_regs. This
    43	 * tells the ftrace_caller that there's a direct caller.
    44	 */
  > 45	static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs, unsigned long addr)
    46	{
  > 47		struct pt_regs *regs = ftrace_get_regs(fregs);
    48	
    49		/* Emulate a call */
    50		regs->orig_ax = addr;
    51	}
    52	

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