| 1 |
9 |
jlechner |
/* Copyright (C) 1992, 93, 95, 96, 97, 98, 99, 00 Free Software Foundation, Inc.
|
| 2 |
|
|
This file is part of the GNU C Library.
|
| 3 |
|
|
Contributed by Ulrich Drepper, <drepper@gnu.org>, August 1995.
|
| 4 |
|
|
|
| 5 |
|
|
The GNU C Library is free software; you can redistribute it and/or
|
| 6 |
|
|
modify it under the terms of the GNU Lesser General Public
|
| 7 |
|
|
License as published by the Free Software Foundation; either
|
| 8 |
|
|
version 2.1 of the License, or (at your option) any later version.
|
| 9 |
|
|
|
| 10 |
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
| 11 |
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
| 12 |
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
| 13 |
|
|
Lesser General Public License for more details.
|
| 14 |
|
|
|
| 15 |
|
|
You should have received a copy of the GNU Lesser General Public
|
| 16 |
|
|
License along with the GNU C Library; if not, write to the Free
|
| 17 |
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
| 18 |
|
|
02111-1307 USA. */
|
| 19 |
|
|
|
| 20 |
|
|
#ifndef _LINUX_I386_SYSDEP_H
|
| 21 |
|
|
#define _LINUX_I386_SYSDEP_H 1
|
| 22 |
|
|
|
| 23 |
|
|
#include "i386-sysdep.h"
|
| 24 |
|
|
|
| 25 |
|
|
/* For Linux we can use the system call table in the header file
|
| 26 |
|
|
/usr/include/asm/unistd.h
|
| 27 |
|
|
of the kernel. But these symbols do not follow the SYS_* syntax
|
| 28 |
|
|
so we have to redefine the `SYS_ify' macro here. */
|
| 29 |
|
|
#undef SYS_ify
|
| 30 |
|
|
#define SYS_ify(syscall_name) __NR_##syscall_name
|
| 31 |
|
|
|
| 32 |
|
|
/* ELF-like local names start with `.L'. */
|
| 33 |
|
|
#undef L
|
| 34 |
|
|
#define L(name) .L##name
|
| 35 |
|
|
|
| 36 |
|
|
#ifdef __ASSEMBLER__
|
| 37 |
|
|
|
| 38 |
|
|
/* Linux uses a negative return value to indicate syscall errors,
|
| 39 |
|
|
unlike most Unices, which use the condition codes' carry flag.
|
| 40 |
|
|
|
| 41 |
|
|
Since version 2.1 the return value of a system call might be
|
| 42 |
|
|
negative even if the call succeeded. E.g., the `lseek' system call
|
| 43 |
|
|
might return a large offset. Therefore we must not anymore test
|
| 44 |
|
|
for < 0, but test for a real error by making sure the value in %eax
|
| 45 |
|
|
is a real error number. Linus said he will make sure the no syscall
|
| 46 |
|
|
returns a value in -1 .. -4095 as a valid result so we can savely
|
| 47 |
|
|
test with -4095. */
|
| 48 |
|
|
|
| 49 |
|
|
/* We don't want the label for the error handle to be global when we define
|
| 50 |
|
|
it here. */
|
| 51 |
|
|
#ifdef PIC
|
| 52 |
|
|
# define SYSCALL_ERROR_LABEL 0f
|
| 53 |
|
|
#else
|
| 54 |
|
|
# define SYSCALL_ERROR_LABEL syscall_error
|
| 55 |
|
|
#endif
|
| 56 |
|
|
|
| 57 |
|
|
#undef PSEUDO
|
| 58 |
|
|
#define PSEUDO(name, syscall_name, args) \
|
| 59 |
|
|
.text; \
|
| 60 |
|
|
ENTRY (name) \
|
| 61 |
|
|
DO_CALL (args, syscall_name); \
|
| 62 |
|
|
cmpl $-4095, %eax; \
|
| 63 |
|
|
jae SYSCALL_ERROR_LABEL; \
|
| 64 |
|
|
L(pseudo_end):
|
| 65 |
|
|
|
| 66 |
|
|
#undef PSEUDO_END
|
| 67 |
|
|
#define PSEUDO_END(name) \
|
| 68 |
|
|
SYSCALL_ERROR_HANDLER \
|
| 69 |
|
|
END (name)
|
| 70 |
|
|
|
| 71 |
|
|
#ifndef PIC
|
| 72 |
|
|
#define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
|
| 73 |
|
|
#else
|
| 74 |
|
|
/* Store (- %eax) into errno through the GOT. */
|
| 75 |
|
|
#ifdef _LIBC_REENTRANT
|
| 76 |
|
|
#define SYSCALL_ERROR_HANDLER \
|
| 77 |
|
|
0:pushl %ebx; \
|
| 78 |
|
|
call 1f; \
|
| 79 |
|
|
1:popl %ebx; \
|
| 80 |
|
|
xorl %edx, %edx; \
|
| 81 |
|
|
addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %ebx; \
|
| 82 |
|
|
subl %eax, %edx; \
|
| 83 |
|
|
pushl %edx; \
|
| 84 |
|
|
PUSH_ERRNO_LOCATION_RETURN; \
|
| 85 |
|
|
call BP_SYM (__errno_location)@PLT; \
|
| 86 |
|
|
POP_ERRNO_LOCATION_RETURN; \
|
| 87 |
|
|
popl %ecx; \
|
| 88 |
|
|
popl %ebx; \
|
| 89 |
|
|
movl %ecx, (%eax); \
|
| 90 |
|
|
orl $-1, %eax; \
|
| 91 |
|
|
jmp L(pseudo_end);
|
| 92 |
|
|
/* A quick note: it is assumed that the call to `__errno_location' does
|
| 93 |
|
|
not modify the stack! */
|
| 94 |
|
|
#else
|
| 95 |
|
|
#define SYSCALL_ERROR_HANDLER \
|
| 96 |
|
|
0:call 1f; \
|
| 97 |
|
|
1:popl %ecx; \
|
| 98 |
|
|
xorl %edx, %edx; \
|
| 99 |
|
|
addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %ecx; \
|
| 100 |
|
|
subl %eax, %edx; \
|
| 101 |
|
|
movl errno@GOT(%ecx), %ecx; \
|
| 102 |
|
|
movl %edx, (%ecx); \
|
| 103 |
|
|
orl $-1, %eax; \
|
| 104 |
|
|
jmp L(pseudo_end);
|
| 105 |
|
|
#endif /* _LIBC_REENTRANT */
|
| 106 |
|
|
#endif /* PIC */
|
| 107 |
|
|
|
| 108 |
|
|
/* Linux takes system call arguments in registers:
|
| 109 |
|
|
|
| 110 |
|
|
syscall number %eax call-clobbered
|
| 111 |
|
|
arg 1 %ebx call-saved
|
| 112 |
|
|
arg 2 %ecx call-clobbered
|
| 113 |
|
|
arg 3 %edx call-clobbered
|
| 114 |
|
|
arg 4 %esi call-saved
|
| 115 |
|
|
arg 5 %edi call-saved
|
| 116 |
|
|
|
| 117 |
|
|
The stack layout upon entering the function is:
|
| 118 |
|
|
|
| 119 |
|
|
20(%esp) Arg# 5
|
| 120 |
|
|
16(%esp) Arg# 4
|
| 121 |
|
|
12(%esp) Arg# 3
|
| 122 |
|
|
8(%esp) Arg# 2
|
| 123 |
|
|
4(%esp) Arg# 1
|
| 124 |
|
|
(%esp) Return address
|
| 125 |
|
|
|
| 126 |
|
|
(Of course a function with say 3 arguments does not have entries for
|
| 127 |
|
|
arguments 4 and 5.)
|
| 128 |
|
|
|
| 129 |
|
|
The following code tries hard to be optimal. A general assumption
|
| 130 |
|
|
(which is true according to the data books I have) is that
|
| 131 |
|
|
|
| 132 |
|
|
2 * xchg is more expensive than pushl + movl + popl
|
| 133 |
|
|
|
| 134 |
|
|
Beside this a neat trick is used. The calling conventions for Linux
|
| 135 |
|
|
tell that among the registers used for parameters %ecx and %edx need
|
| 136 |
|
|
not be saved. Beside this we may clobber this registers even when
|
| 137 |
|
|
they are not used for parameter passing.
|
| 138 |
|
|
|
| 139 |
|
|
As a result one can see below that we save the content of the %ebx
|
| 140 |
|
|
register in the %edx register when we have less than 3 arguments
|
| 141 |
|
|
(2 * movl is less expensive than pushl + popl).
|
| 142 |
|
|
|
| 143 |
|
|
Second unlike for the other registers we don't save the content of
|
| 144 |
|
|
%ecx and %edx when we have more than 1 and 2 registers resp.
|
| 145 |
|
|
|
| 146 |
|
|
The code below might look a bit long but we have to take care for
|
| 147 |
|
|
the pipelined processors (i586). Here the `pushl' and `popl'
|
| 148 |
|
|
instructions are marked as NP (not pairable) but the exception is
|
| 149 |
|
|
two consecutive of these instruction. This gives no penalty on
|
| 150 |
|
|
other processors though. */
|
| 151 |
|
|
|
| 152 |
|
|
#undef DO_CALL
|
| 153 |
|
|
#define DO_CALL(args, syscall_name) \
|
| 154 |
|
|
PUSHARGS_##args \
|
| 155 |
|
|
DOARGS_##args \
|
| 156 |
|
|
movl $SYS_ify (syscall_name), %eax; \
|
| 157 |
|
|
int $0x80 \
|
| 158 |
|
|
POPARGS_##args
|
| 159 |
|
|
|
| 160 |
|
|
#define PUSHARGS_0 /* No arguments to push. */
|
| 161 |
|
|
#define DOARGS_0 /* No arguments to frob. */
|
| 162 |
|
|
#define POPARGS_0 /* No arguments to pop. */
|
| 163 |
|
|
#define _PUSHARGS_0 /* No arguments to push. */
|
| 164 |
|
|
#define _DOARGS_0(n) /* No arguments to frob. */
|
| 165 |
|
|
#define _POPARGS_0 /* No arguments to pop. */
|
| 166 |
|
|
|
| 167 |
|
|
#define PUSHARGS_1 movl %ebx, %edx; PUSHARGS_0
|
| 168 |
|
|
#define DOARGS_1 _DOARGS_1 (4)
|
| 169 |
|
|
#define POPARGS_1 POPARGS_0; movl %edx, %ebx
|
| 170 |
|
|
#define _PUSHARGS_1 pushl %ebx; _PUSHARGS_0
|
| 171 |
|
|
#define _DOARGS_1(n) movl n(%esp), %ebx; _DOARGS_0(n-4)
|
| 172 |
|
|
#define _POPARGS_1 _POPARGS_0; popl %ebx
|
| 173 |
|
|
|
| 174 |
|
|
#define PUSHARGS_2 PUSHARGS_1
|
| 175 |
|
|
#define DOARGS_2 _DOARGS_2 (8)
|
| 176 |
|
|
#define POPARGS_2 POPARGS_1
|
| 177 |
|
|
#define _PUSHARGS_2 _PUSHARGS_1
|
| 178 |
|
|
#define _DOARGS_2(n) movl n(%esp), %ecx; _DOARGS_1 (n-4)
|
| 179 |
|
|
#define _POPARGS_2 _POPARGS_1
|
| 180 |
|
|
|
| 181 |
|
|
#define PUSHARGS_3 _PUSHARGS_2
|
| 182 |
|
|
#define DOARGS_3 _DOARGS_3 (16)
|
| 183 |
|
|
#define POPARGS_3 _POPARGS_3
|
| 184 |
|
|
#define _PUSHARGS_3 _PUSHARGS_2
|
| 185 |
|
|
#define _DOARGS_3(n) movl n(%esp), %edx; _DOARGS_2 (n-4)
|
| 186 |
|
|
#define _POPARGS_3 _POPARGS_2
|
| 187 |
|
|
|
| 188 |
|
|
#define PUSHARGS_4 _PUSHARGS_4
|
| 189 |
|
|
#define DOARGS_4 _DOARGS_4 (24)
|
| 190 |
|
|
#define POPARGS_4 _POPARGS_4
|
| 191 |
|
|
#define _PUSHARGS_4 pushl %esi; _PUSHARGS_3
|
| 192 |
|
|
#define _DOARGS_4(n) movl n(%esp), %esi; _DOARGS_3 (n-4)
|
| 193 |
|
|
#define _POPARGS_4 _POPARGS_3; popl %esi
|
| 194 |
|
|
|
| 195 |
|
|
#define PUSHARGS_5 _PUSHARGS_5
|
| 196 |
|
|
#define DOARGS_5 _DOARGS_5 (32)
|
| 197 |
|
|
#define POPARGS_5 _POPARGS_5
|
| 198 |
|
|
#define _PUSHARGS_5 pushl %edi; _PUSHARGS_4
|
| 199 |
|
|
#define _DOARGS_5(n) movl n(%esp), %edi; _DOARGS_4 (n-4)
|
| 200 |
|
|
#define _POPARGS_5 _POPARGS_4; popl %edi
|
| 201 |
|
|
|
| 202 |
|
|
#else /* !__ASSEMBLER__ */
|
| 203 |
|
|
|
| 204 |
|
|
/* We need some help from the assembler to generate optimal code. We
|
| 205 |
|
|
define some macros here which later will be used. */
|
| 206 |
|
|
asm (".L__X'%ebx = 1\n\t"
|
| 207 |
|
|
".L__X'%ecx = 2\n\t"
|
| 208 |
|
|
".L__X'%edx = 2\n\t"
|
| 209 |
|
|
".L__X'%eax = 3\n\t"
|
| 210 |
|
|
".L__X'%esi = 3\n\t"
|
| 211 |
|
|
".L__X'%edi = 3\n\t"
|
| 212 |
|
|
".L__X'%ebp = 3\n\t"
|
| 213 |
|
|
".L__X'%esp = 3\n\t"
|
| 214 |
|
|
".macro bpushl name reg\n\t"
|
| 215 |
|
|
".if 1 - \\name\n\t"
|
| 216 |
|
|
".if 2 - \\name\n\t"
|
| 217 |
|
|
"pushl %ebx\n\t"
|
| 218 |
|
|
".else\n\t"
|
| 219 |
|
|
"xchgl \\reg, %ebx\n\t"
|
| 220 |
|
|
".endif\n\t"
|
| 221 |
|
|
".endif\n\t"
|
| 222 |
|
|
".endm\n\t"
|
| 223 |
|
|
".macro bpopl name reg\n\t"
|
| 224 |
|
|
".if 1 - \\name\n\t"
|
| 225 |
|
|
".if 2 - \\name\n\t"
|
| 226 |
|
|
"popl %ebx\n\t"
|
| 227 |
|
|
".else\n\t"
|
| 228 |
|
|
"xchgl \\reg, %ebx\n\t"
|
| 229 |
|
|
".endif\n\t"
|
| 230 |
|
|
".endif\n\t"
|
| 231 |
|
|
".endm\n\t"
|
| 232 |
|
|
".macro bmovl name reg\n\t"
|
| 233 |
|
|
".if 1 - \\name\n\t"
|
| 234 |
|
|
".if 2 - \\name\n\t"
|
| 235 |
|
|
"movl \\reg, %ebx\n\t"
|
| 236 |
|
|
".endif\n\t"
|
| 237 |
|
|
".endif\n\t"
|
| 238 |
|
|
".endm\n\t");
|
| 239 |
|
|
|
| 240 |
|
|
/* Define a macro which expands inline into the wrapper code for a system
|
| 241 |
|
|
call. */
|
| 242 |
|
|
#undef INLINE_SYSCALL
|
| 243 |
|
|
#define INLINE_SYSCALL(name, nr, args...) \
|
| 244 |
|
|
({ \
|
| 245 |
|
|
unsigned int resultvar; \
|
| 246 |
|
|
asm volatile ( \
|
| 247 |
|
|
LOADARGS_##nr \
|
| 248 |
|
|
"movl %1, %%eax\n\t" \
|
| 249 |
|
|
"int $0x80\n\t" \
|
| 250 |
|
|
RESTOREARGS_##nr \
|
| 251 |
|
|
: "=a" (resultvar) \
|
| 252 |
|
|
: "i" (__NR_##name) ASMFMT_##nr(args) : "memory", "cc"); \
|
| 253 |
|
|
if (resultvar >= 0xfffff001) \
|
| 254 |
|
|
{ \
|
| 255 |
|
|
__set_errno (-resultvar); \
|
| 256 |
|
|
resultvar = 0xffffffff; \
|
| 257 |
|
|
} \
|
| 258 |
|
|
(int) resultvar; })
|
| 259 |
|
|
|
| 260 |
|
|
#define LOADARGS_0
|
| 261 |
|
|
#define LOADARGS_1 \
|
| 262 |
|
|
"bpushl .L__X'%k2, %k2\n\t" \
|
| 263 |
|
|
"bmovl .L__X'%k2, %k2\n\t"
|
| 264 |
|
|
#define LOADARGS_2 LOADARGS_1
|
| 265 |
|
|
#define LOADARGS_3 LOADARGS_1
|
| 266 |
|
|
#define LOADARGS_4 LOADARGS_1
|
| 267 |
|
|
#define LOADARGS_5 LOADARGS_1
|
| 268 |
|
|
|
| 269 |
|
|
#define RESTOREARGS_0
|
| 270 |
|
|
#define RESTOREARGS_1 \
|
| 271 |
|
|
"bpopl .L__X'%k2, %k2\n\t"
|
| 272 |
|
|
#define RESTOREARGS_2 RESTOREARGS_1
|
| 273 |
|
|
#define RESTOREARGS_3 RESTOREARGS_1
|
| 274 |
|
|
#define RESTOREARGS_4 RESTOREARGS_1
|
| 275 |
|
|
#define RESTOREARGS_5 RESTOREARGS_1
|
| 276 |
|
|
|
| 277 |
|
|
#define ASMFMT_0()
|
| 278 |
|
|
#define ASMFMT_1(arg1) \
|
| 279 |
|
|
, "acdSD" (arg1)
|
| 280 |
|
|
#define ASMFMT_2(arg1, arg2) \
|
| 281 |
|
|
, "adCD" (arg1), "c" (arg2)
|
| 282 |
|
|
#define ASMFMT_3(arg1, arg2, arg3) \
|
| 283 |
|
|
, "aCD" (arg1), "c" (arg2), "d" (arg3)
|
| 284 |
|
|
#define ASMFMT_4(arg1, arg2, arg3, arg4) \
|
| 285 |
|
|
, "aD" (arg1), "c" (arg2), "d" (arg3), "S" (arg4)
|
| 286 |
|
|
#define ASMFMT_5(arg1, arg2, arg3, arg4, arg5) \
|
| 287 |
|
|
, "a" (arg1), "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
|
| 288 |
|
|
|
| 289 |
|
|
#endif /* __ASSEMBLER__ */
|
| 290 |
|
|
|
| 291 |
|
|
#endif /* linux/i386/sysdep.h */
|
