sys/cpu/i386/include/asmacros.h

   1 /*-
   2  * Copyright (c) 1993 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/sys/i386/include/asmacros.h,v 1.18 1999/08/28 00:44:06 peter Exp $
  34  * $DragonFly: src/sys/cpu/i386/include/asmacros.h,v 1.11 2006/11/07 06:43:22 dillon Exp $
  35  */
  36
  37 #ifndef _CPU_ASMACROS_H_
  38 #define _CPU_ASMACROS_H_
  39
  40 #ifndef _SYS_CDEFS_H_
  41 #include <sys/cdefs.h>
  42 #endif
  43
  44 #ifdef _KERNEL
  45
  46 /*
  47  * Access to a per-cpu data element
  48  */
  49 #define PCPU(x) %fs:gd_ ## x
  50 #define MYCPU   %fs:0
  51
  52 #endif
  53
  54 #ifdef LOCORE
  55 /*
  56  * Interrupt vector labels
  57  */
  58 #define IDTVEC(name)    ALIGN_TEXT; .globl __CONCAT(X,name); \
  59                         .type __CONCAT(X,name),@function; __CONCAT(X,name):
  60
  61 #endif
  62
  63 /*
  64  * CNAME and HIDENAME manage the relationship between symbol names in C
  65  * and the equivalent assembly language names.  CNAME is given a name as
  66  * it would be used in a C program.  It expands to the equivalent assembly
  67  * language name.  HIDENAME is given an assembly-language name, and expands
  68  * to a possibly-modified form that will be invisible to C programs.
  69  */
  70 #define CNAME(csym)             csym
  71 #define HIDENAME(asmsym)        __CONCAT(.,asmsym)
  72
  73 #define ALIGN_PAGE      .p2align PAGE_SHIFT     /* page alignment */
  74 #define ALIGN_DATA      .p2align 2      /* 4 byte alignment, zero filled */
  75 #ifdef GPROF
  76 #define ALIGN_TEXT      .p2align 4,0x90 /* 16-byte alignment, nop filled */
  77 #else
  78 #define ALIGN_TEXT      .p2align 2,0x90 /* 4-byte alignment, nop filled */
  79 #endif
  80 #define SUPERALIGN_TEXT .p2align 4,0x90 /* 16-byte alignment, nop filled */
  81
  82 #define GEN_ENTRY(name)         ALIGN_TEXT; .globl CNAME(name); \
  83                                 .type CNAME(name),@function; CNAME(name):
  84 #define NON_GPROF_ENTRY(name)   GEN_ENTRY(name)
  85 #define NON_GPROF_RET           .byte 0xc3      /* opcode for `ret' */
  86
  87 #ifdef GPROF
  88 /*
  89  * __mcount is like [.]mcount except that doesn't require its caller to set
  90  * up a frame pointer.  It must be called before pushing anything onto the
  91  * stack.  gcc should eventually generate code to call __mcount in most
  92  * cases.  This would make -pg in combination with -fomit-frame-pointer
  93  * useful.  gcc has a configuration variable PROFILE_BEFORE_PROLOGUE to
  94  * allow profiling before setting up the frame pointer, but this is
  95  * inadequate for good handling of special cases, e.g., -fpic works best
  96  * with profiling after the prologue.
  97  *
  98  * [.]mexitcount is a new function to support non-statistical profiling if an
  99  * accurate clock is available.  For C sources, calls to it are generated
 100  * by the FreeBSD extension `-mprofiler-epilogue' to gcc.  It is best to
 101  * call [.]mexitcount at the end of a function like the MEXITCOUNT macro does,
 102  * but gcc currently generates calls to it at the start of the epilogue to
 103  * avoid problems with -fpic.
 104  *
 105  * [.]mcount and __mcount will not clobber the call-used registers or %ef.
 106  * [.]mexitcount will not clobber the call-used registers or %ef.
 107  *
 108  * Cross-jumping makes non-statistical profiling timing more complicated.
 109  * It is handled in many cases by calling [.]mexitcount before jumping.  It
 110  * is handled for conditional jumps using CROSSJUMP() and CROSSJUMP_LABEL().
 111  * It is handled for some fault-handling jumps by not sharing the exit
 112  * routine.
 113  *
 114  * ALTENTRY() must be before a corresponding ENTRY() so that it can jump to
 115  * the main entry point.  Note that alt entries are counted twice.  They
 116  * have to be counted as ordinary entries for gprof to get the call times
 117  * right for the ordinary entries.
 118  *
 119  * High local labels are used in macros to avoid clashes with local labels
 120  * in functions.
 121  *
 122  * Ordinary `ret' is used instead of a macro `RET' because there are a lot
 123  * of `ret's.  0xc3 is the opcode for `ret' (`#define ret ... ret' can't
 124  * be used because this file is sometimes preprocessed in traditional mode).
 125  * `ret' clobbers eflags but this doesn't matter.
 126  */
 127 #define ALTENTRY(name)          GEN_ENTRY(name) ; MCOUNT ; MEXITCOUNT ; jmp 9f
 128 #define CROSSJUMP(jtrue, label, jfalse) \
 129         jfalse 8f; MEXITCOUNT; jmp __CONCAT(to,label); 8:
 130 #define CROSSJUMPTARGET(label) \
 131         ALIGN_TEXT; __CONCAT(to,label): ; MCOUNT; jmp label
 132 #define ENTRY(name)             GEN_ENTRY(name) ; 9: ; MCOUNT
 133 #define FAKE_MCOUNT(caller)     pushl caller ; call __mcount ; addl $4,%esp
 134 #define MCOUNT                  call __mcount
 135 #define MCOUNT_LABEL(name)      GEN_ENTRY(name) ; nop ; ALIGN_TEXT
 136 #define MEXITCOUNT              call HIDENAME(mexitcount)
 137 #define ret                     MEXITCOUNT ; NON_GPROF_RET
 138
 139 #else /* !GPROF */
 140 /*
 141  * ALTENTRY() has to align because it is before a corresponding ENTRY().
 142  * ENTRY() has to align to because there may be no ALTENTRY() before it.
 143  * If there is a previous ALTENTRY() then the alignment code for ENTRY()
 144  * is empty.
 145  */
 146 #define ALTENTRY(name)          GEN_ENTRY(name)
 147 #define CROSSJUMP(jtrue, label, jfalse) jtrue label
 148 #define CROSSJUMPTARGET(label)
 149 #define ENTRY(name)             GEN_ENTRY(name)
 150 #define FAKE_MCOUNT(caller)
 151 #define MCOUNT
 152 #define MCOUNT_LABEL(name)
 153 #define MEXITCOUNT
 154 #endif /* GPROF */
 155
 156 #endif /* !_CPU_ASMACROS_H_ */