sysdeps/unix/bsd/bsd4.4/kfreebsd/i386/sysdep.h

   1 /* Copyright (C) 1992,1993,1995-2000,2002,2003,2004
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper, <drepper@gnu.org>, August 1995.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #ifndef _FREEBSD_I386_SYSDEP_H
  22 #define _FREEBSD_I386_SYSDEP_H 1
  23
  24 /* There is some commonality.  */
  25 #include <sysdeps/unix/i386/sysdep.h>
  26 /* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO.  */
  27 #include <dl-sysdep.h>
  28 #include <tls.h>
  29
  30 #ifdef __ASSEMBLER__
  31
  32 /* We don't want the label for the error handle to be global when we define
  33    it here.  */
  34 #ifdef PIC
  35 # define SYSCALL_ERROR_LABEL 0f
  36 #else
  37 # define SYSCALL_ERROR_LABEL syscall_error
  38 #endif
  39
  40 #undef  PSEUDO
  41 #define PSEUDO(name, syscall_name, args)                                      \
  42   .text;                                                                      \
  43   ENTRY (name)                                                                \
  44     DO_CALL (syscall_name, args);                                             \
  45     jb SYSCALL_ERROR_LABEL;                                                   \
  46   L(pseudo_end):
  47
  48 #undef  PSEUDO_END
  49 #define PSEUDO_END(name)                                                      \
  50   SYSCALL_ERROR_HANDLER                                                       \
  51   END (name)
  52
  53 #undef  PSEUDO_NOERRNO
  54 #define PSEUDO_NOERRNO(name, syscall_name, args)                              \
  55   .text;                                                                      \
  56   ENTRY (name)                                                                \
  57     DO_CALL (syscall_name, args)
  58
  59 #undef  PSEUDO_END_NOERRNO
  60 #define PSEUDO_END_NOERRNO(name)                                              \
  61   END (name)
  62
  63 #define ret_NOERRNO ret
  64
  65 /* The function has to return the error code.  */
  66 #undef  PSEUDO_ERRVAL
  67 #define PSEUDO_ERRVAL(name, syscall_name, args) \
  68   .text;                                                                      \
  69   ENTRY (name)                                                                \
  70     DO_CALL (syscall_name, args);                                             \
  71
  72 #undef  PSEUDO_END_ERRVAL
  73 #define PSEUDO_END_ERRVAL(name) \
  74   END (name)
  75
  76 #define ret_ERRVAL ret
  77
  78 #ifndef PIC
  79 # define SYSCALL_ERROR_HANDLER  /* Nothing here; code in sysdep.S is used.  */
  80 #else
  81
  82 # if RTLD_PRIVATE_ERRNO
  83 #  define SYSCALL_ERROR_HANDLER                                               \
  84 0:SETUP_PIC_REG(cx);                                                          \
  85   addl $_GLOBAL_OFFSET_TABLE_, %ecx;                                          \
  86   movl %eax, rtld_errno@GOTOFF(%ecx);                                         \
  87   orl $-1, %eax;                                                              \
  88   jmp L(pseudo_end);
  89
  90 # elif defined _LIBC_REENTRANT
  91
  92 #  if IS_IN (libc)
  93 #   define SYSCALL_ERROR_ERRNO __libc_errno
  94 #  else
  95 #   define SYSCALL_ERROR_ERRNO errno
  96 #  endif
  97 #  define SYSCALL_ERROR_HANDLER                                       \
  98 0:SETUP_PIC_REG (cx);                                                         \
  99   addl $_GLOBAL_OFFSET_TABLE_, %ecx;                                          \
 100   movl SYSCALL_ERROR_ERRNO@GOTNTPOFF(%ecx), %ecx;                             \
 101   SYSCALL_ERROR_HANDLER_TLS_STORE (%eax, %ecx);                               \
 102   orl $-1, %eax;                                                              \
 103   jmp L(pseudo_end);
 104 #  ifndef NO_TLS_DIRECT_SEG_REFS
 105 #   define SYSCALL_ERROR_HANDLER_TLS_STORE(src, destoff)                      \
 106   movl src, %gs:(destoff)
 107 #  else
 108 #   define SYSCALL_ERROR_HANDLER_TLS_STORE(src, destoff)                      \
 109   addl %gs:0, destoff;                                                        \
 110   movl src, (destoff)
 111 #  endif
 112 # else
 113 /* Store (%eax) into errno through the GOT.  */
 114 #  define SYSCALL_ERROR_HANDLER                                               \
 115 0:SETUP_PIC_REG(cx);                                                          \
 116   addl $_GLOBAL_OFFSET_TABLE_, %ecx;                                          \
 117   movl errno@GOT(%ecx), %ecx;                                                 \
 118   movl %eax, (%ecx);                                                          \
 119   orl $-1, %eax;                                                              \
 120   jmp L(pseudo_end);
 121 # endif /* _LIBC_REENTRANT */
 122 #endif  /* PIC */
 123
 124 /*
 125     FreeBSD expects the system call arguments on the stack,
 126    syscall number is in %eax.
 127    return value is in %eax + %edx
 128    error is signaled via cflags.
 129    all other data registers are preserved
 130
 131         syscall number  %eax         call-clobbered
 132
 133    The stack layout upon entering the function is:
 134
 135         20(%esp)        Arg# 5
 136         16(%esp)        Arg# 4
 137         12(%esp)        Arg# 3
 138          8(%esp)        Arg# 2
 139          4(%esp)        Arg# 1
 140           (%esp)        Return address
 141
 142    (Of course a function with say 3 arguments does not have entries for
 143    arguments 4 and 5.)
 144
 145 */
 146
 147 #undef  DO_CALL
 148 #define DO_CALL(syscall_name, args)                                           \
 149     movl $SYS_ify (syscall_name), %eax;                                       \
 150     int $0x80                                                                 \
 151
 152 #else   /* !__ASSEMBLER__ */
 153
 154 #include <syscalls-inline.h>
 155
 156 /* Consistency check for position-independent code.  */
 157 #if defined __PIC__ && !__GNUC_PREREQ (5,0)
 158 # define check_consistency()                                                  \
 159   ({ int __res;                                                               \
 160      __asm__ __volatile__                                                     \
 161        (LOAD_PIC_REG_STR (cx) ";"                                             \
 162         "subl %%ebx, %%ecx;"                                                  \
 163         "je 1f;"                                                              \
 164         "ud2;"                                                                \
 165         "1:\n"                                                                \
 166         : "=c" (__res));                                                      \
 167      __res; })
 168 #endif
 169
 170 #endif  /* __ASSEMBLER__ */
 171
 172
 173 /* Pointer mangling support.  */
 174 #if IS_IN (rtld)
 175 /* We cannot use the thread descriptor because in ld.so we use setjmp
 176    earlier than the descriptor is initialized.  Using a global variable
 177    is too complicated here since we have no PC-relative addressing mode.  */
 178 #else
 179 # ifdef __ASSEMBLER__
 180 #  define PTR_MANGLE(reg)       xorl %gs:POINTER_GUARD, reg;                  \
 181                                 roll $9, reg
 182 #  define PTR_DEMANGLE(reg)     rorl $9, reg;                                 \
 183                                 xorl %gs:POINTER_GUARD, reg
 184 # else
 185 #  define PTR_MANGLE(var)       asm ("xorl %%gs:%c2, %0\n"                    \
 186                                      "roll $9, %0"                            \
 187                                      : "=r" (var)                             \
 188                                      : "0" (var),                             \
 189                                        "i" (offsetof (tcbhead_t,              \
 190                                                       pointer_guard)))
 191 #  define PTR_DEMANGLE(var)     asm ("rorl $9, %0\n"                          \
 192                                      "xorl %%gs:%c2, %0"                      \
 193                                      : "=r" (var)                             \
 194                                      : "0" (var),                             \
 195                                        "i" (offsetof (tcbhead_t,              \
 196                                                       pointer_guard)))
 197 # endif
 198 #endif
 199
 200 #endif /* _FREEBSD_I386_SYSDEP_H */