FreeBSD/Linux Kernel Cross Reference
sys/amd64/include/profile.h

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 1992, 1993
      *      The Regents of the University of California.  All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)profile.h   8.1 (Berkeley) 6/11/93
     * $FreeBSD$
     */
    
    #ifdef __i386__
    #include <i386/profile.h>
    #else /* !__i386__ */
    
    #ifndef _MACHINE_PROFILE_H_
    #define _MACHINE_PROFILE_H_
    
    #ifndef _KERNEL
    
    #include <sys/cdefs.h>
    
    #define FUNCTION_ALIGNMENT      4
    
    #define _MCOUNT_DECL \
    static void _mcount(uintfptr_t frompc, uintfptr_t selfpc) __used; \
    static void _mcount
    
    #define MCOUNT __asm("                  \n\
            .text                           \n\
            .p2align 4,0x90                 \n\
            .globl  .mcount                 \n\
            .type   .mcount,@function       \n\
    .mcount:                                \n\
            pushq   %rdi                    \n\
            pushq   %rsi                    \n\
            pushq   %rdx                    \n\
            pushq   %rcx                    \n\
            pushq   %r8                     \n\
            pushq   %r9                     \n\
            pushq   %rax                    \n\
            movq    8(%rbp),%rdi            \n\
            movq    7*8(%rsp),%rsi          \n\
            call    _mcount                 \n\
            popq    %rax                    \n\
            popq    %r9                     \n\
            popq    %r8                     \n\
            popq    %rcx                    \n\
            popq    %rdx                    \n\
            popq    %rsi                    \n\
            popq    %rdi                    \n\
            ret                             \n\
            .size   .mcount, . - .mcount");
    #if 0
    /*
     * We could use this, except it doesn't preserve the registers that were
     * being passed with arguments to the function that we were inserted
     * into.  I've left it here as documentation of what the code above is
     * supposed to do.
     */
    #define MCOUNT                                                          \
    void                                                                    \
    mcount()                                                                \
    {                                                                       \
            uintfptr_t selfpc, frompc;                                      \
            /*                                                              \
             * Find the return address for mcount,                          \
             * and the return address for mcount's caller.                  \
             *                                                              \
             * selfpc = pc pushed by call to mcount                         \
             */                                                             \
            __asm("movq 8(%%rbp),%0" : "=r" (selfpc));                      \
            /*                                                              \
             * frompc = pc pushed by call to mcount's caller.               \
             * The caller's stack frame has already been built, so %rbp is  \
             * the caller's frame pointer.  The caller's raddr is in the    \
            * caller's frame following the caller's caller's frame pointer.\
            */                                                             \
           __asm("movq (%%rbp),%0" : "=r" (frompc));                       \
           frompc = ((uintfptr_t *)frompc)[1];                             \
           _mcount(frompc, selfpc);                                        \
   }
   #endif
   
   typedef u_long  uintfptr_t;
   
   /*
    * An unsigned integral type that can hold non-negative difference between
    * function pointers.
    */
   typedef u_long  fptrdiff_t;
   
   __BEGIN_DECLS
   void    mcount(void) __asm(".mcount");
   __END_DECLS
   
   #endif /* !_KERNEL */
   
   #endif /* !_MACHINE_PROFILE_H_ */
   
   #endif /* __i386__ */

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