1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
|
/* Copyright (C) 2001-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _LINUX_X86_64_SYSDEP_H
#define _LINUX_X86_64_SYSDEP_H 1
/* There is some commonality. */
#include <sysdeps/unix/x86_64/sysdep.h>
#include <tls.h>
#ifdef IS_IN_rtld
# include <dl-sysdep.h> /* Defines RTLD_PRIVATE_ERRNO. */
#endif
/* For Linux we can use the system call table in the header file
/usr/include/asm/unistd.h
of the kernel. But these symbols do not follow the SYS_* syntax
so we have to redefine the `SYS_ify' macro here. */
#undef SYS_ify
#define SYS_ify(syscall_name) __NR_##syscall_name
/* This is a kludge to make syscalls.list find these under the names
pread and pwrite, since some kernel headers define those names
and some define the *64 names for the same system calls. */
#if !defined __NR_pread && defined __NR_pread64
# define __NR_pread __NR_pread64
#endif
#if !defined __NR_pwrite && defined __NR_pwrite64
# define __NR_pwrite __NR_pwrite64
#endif
/* This is to help the old kernel headers where __NR_semtimedop is not
available. */
#ifndef __NR_semtimedop
# define __NR_semtimedop 220
#endif
#ifdef __ASSEMBLER__
/* Linux uses a negative return value to indicate syscall errors,
unlike most Unices, which use the condition codes' carry flag.
Since version 2.1 the return value of a system call might be
negative even if the call succeeded. E.g., the `lseek' system call
might return a large offset. Therefore we must not anymore test
for < 0, but test for a real error by making sure the value in %eax
is a real error number. Linus said he will make sure the no syscall
returns a value in -1 .. -4095 as a valid result so we can savely
test with -4095. */
/* We don't want the label for the error handle to be global when we define
it here. */
# ifdef PIC
# define SYSCALL_ERROR_LABEL 0f
# else
# define SYSCALL_ERROR_LABEL syscall_error
# endif
# undef PSEUDO
# define PSEUDO(name, syscall_name, args) \
.text; \
ENTRY (name) \
DO_CALL (syscall_name, args); \
cmpq $-4095, %rax; \
jae SYSCALL_ERROR_LABEL
# undef PSEUDO_END
# define PSEUDO_END(name) \
SYSCALL_ERROR_HANDLER \
END (name)
# undef PSEUDO_NOERRNO
# define PSEUDO_NOERRNO(name, syscall_name, args) \
.text; \
ENTRY (name) \
DO_CALL (syscall_name, args)
# undef PSEUDO_END_NOERRNO
# define PSEUDO_END_NOERRNO(name) \
END (name)
# define ret_NOERRNO ret
# undef PSEUDO_ERRVAL
# define PSEUDO_ERRVAL(name, syscall_name, args) \
.text; \
ENTRY (name) \
DO_CALL (syscall_name, args); \
negq %rax
# undef PSEUDO_END_ERRVAL
# define PSEUDO_END_ERRVAL(name) \
END (name)
# define ret_ERRVAL ret
# if defined PIC && defined RTLD_PRIVATE_ERRNO
# define SYSCALL_SET_ERRNO \
lea rtld_errno(%rip), %RCX_LP; \
neg %eax; \
movl %eax, (%rcx)
# else
# ifndef NOT_IN_libc
# define SYSCALL_ERROR_ERRNO __libc_errno
# else
# define SYSCALL_ERROR_ERRNO errno
# endif
# define SYSCALL_SET_ERRNO \
movq SYSCALL_ERROR_ERRNO@GOTTPOFF(%rip), %rcx;\
neg %eax; \
movl %eax, %fs:(%rcx);
# endif
# ifndef PIC
# define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
# else
# define SYSCALL_ERROR_HANDLER \
0: \
SYSCALL_SET_ERRNO; \
or $-1, %RAX_LP; \
ret;
# endif /* PIC */
/* The Linux/x86-64 kernel expects the system call parameters in
registers according to the following table:
syscall number rax
arg 1 rdi
arg 2 rsi
arg 3 rdx
arg 4 r10
arg 5 r8
arg 6 r9
The Linux kernel uses and destroys internally these registers:
return address from
syscall rcx
eflags from syscall r11
Normal function call, including calls to the system call stub
functions in the libc, get the first six parameters passed in
registers and the seventh parameter and later on the stack. The
register use is as follows:
system call number in the DO_CALL macro
arg 1 rdi
arg 2 rsi
arg 3 rdx
arg 4 rcx
arg 5 r8
arg 6 r9
We have to take care that the stack is aligned to 16 bytes. When
called the stack is not aligned since the return address has just
been pushed.
Syscalls of more than 6 arguments are not supported. */
# undef DO_CALL
# define DO_CALL(syscall_name, args) \
DOARGS_##args \
movl $SYS_ify (syscall_name), %eax; \
syscall;
# define DOARGS_0 /* nothing */
# define DOARGS_1 /* nothing */
# define DOARGS_2 /* nothing */
# define DOARGS_3 /* nothing */
# define DOARGS_4 movq %rcx, %r10;
# define DOARGS_5 DOARGS_4
# define DOARGS_6 DOARGS_5
#else /* !__ASSEMBLER__ */
/* Define a macro which expands inline into the wrapper code for a system
call. */
# undef INLINE_SYSCALL
# define INLINE_SYSCALL(name, nr, args...) \
({ \
unsigned long int resultvar = INTERNAL_SYSCALL (name, , nr, args); \
if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (resultvar, ))) \
{ \
__set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, )); \
resultvar = (unsigned long int) -1; \
} \
(long int) resultvar; })
/* Define a macro with explicit types for arguments, which expands inline
into the wrapper code for a system call. It should be used when size
of any argument > size of long int. */
# undef INLINE_SYSCALL_TYPES
# define INLINE_SYSCALL_TYPES(name, nr, args...) \
({ \
unsigned long int resultvar = INTERNAL_SYSCALL_TYPES (name, , nr, args); \
if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (resultvar, ))) \
{ \
__set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, )); \
resultvar = (unsigned long int) -1; \
} \
(long int) resultvar; })
# undef INTERNAL_SYSCALL_DECL
# define INTERNAL_SYSCALL_DECL(err) do { } while (0)
# define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
({ \
unsigned long int resultvar; \
LOAD_ARGS_##nr (args) \
LOAD_REGS_##nr \
asm volatile ( \
"syscall\n\t" \
: "=a" (resultvar) \
: "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx"); \
(long int) resultvar; })
# undef INTERNAL_SYSCALL
# define INTERNAL_SYSCALL(name, err, nr, args...) \
INTERNAL_SYSCALL_NCS (__NR_##name, err, nr, ##args)
# define INTERNAL_SYSCALL_NCS_TYPES(name, err, nr, args...) \
({ \
unsigned long int resultvar; \
LOAD_ARGS_TYPES_##nr (args) \
LOAD_REGS_TYPES_##nr (args) \
asm volatile ( \
"syscall\n\t" \
: "=a" (resultvar) \
: "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx"); \
(long int) resultvar; })
# undef INTERNAL_SYSCALL_TYPES
# define INTERNAL_SYSCALL_TYPES(name, err, nr, args...) \
INTERNAL_SYSCALL_NCS_TYPES (__NR_##name, err, nr, ##args)
# undef INTERNAL_SYSCALL_ERROR_P
# define INTERNAL_SYSCALL_ERROR_P(val, err) \
((unsigned long int) (long int) (val) >= -4095L)
# undef INTERNAL_SYSCALL_ERRNO
# define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))
# ifdef SHARED
# define INLINE_VSYSCALL(name, nr, args...) \
({ \
__label__ out; \
__label__ iserr; \
INTERNAL_SYSCALL_DECL (sc_err); \
long int sc_ret; \
\
__typeof (__vdso_##name) vdsop = __vdso_##name; \
PTR_DEMANGLE (vdsop); \
if (vdsop != NULL) \
{ \
sc_ret = vdsop (args); \
if (!INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err)) \
goto out; \
if (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err) != ENOSYS) \
goto iserr; \
} \
\
sc_ret = INTERNAL_SYSCALL (name, sc_err, nr, ##args); \
if (INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err)) \
{ \
iserr: \
__set_errno (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err)); \
sc_ret = -1L; \
} \
out: \
sc_ret; \
})
# define INTERNAL_VSYSCALL(name, err, nr, args...) \
({ \
__label__ out; \
long int v_ret; \
\
__typeof (__vdso_##name) vdsop = __vdso_##name; \
PTR_DEMANGLE (vdsop); \
if (vdsop != NULL) \
{ \
v_ret = vdsop (args); \
if (!INTERNAL_SYSCALL_ERROR_P (v_ret, err) \
|| INTERNAL_SYSCALL_ERRNO (v_ret, err) != ENOSYS) \
goto out; \
} \
v_ret = INTERNAL_SYSCALL (name, err, nr, ##args); \
out: \
v_ret; \
})
# else
# define INLINE_VSYSCALL(name, nr, args...) \
INLINE_SYSCALL (name, nr, ##args)
# define INTERNAL_VSYSCALL(name, err, nr, args...) \
INTERNAL_SYSCALL (name, err, nr, ##args)
# endif
# define LOAD_ARGS_0()
# define LOAD_REGS_0
# define ASM_ARGS_0
# define LOAD_ARGS_TYPES_1(t1, a1) \
t1 __arg1 = (t1) (a1); \
LOAD_ARGS_0 ()
# define LOAD_REGS_TYPES_1(t1, a1) \
register t1 _a1 asm ("rdi") = __arg1; \
LOAD_REGS_0
# define ASM_ARGS_1 ASM_ARGS_0, "r" (_a1)
# define LOAD_ARGS_1(a1) \
LOAD_ARGS_TYPES_1 (long int, a1)
# define LOAD_REGS_1 \
LOAD_REGS_TYPES_1 (long int, a1)
# define LOAD_ARGS_TYPES_2(t1, a1, t2, a2) \
t2 __arg2 = (t2) (a2); \
LOAD_ARGS_TYPES_1 (t1, a1)
# define LOAD_REGS_TYPES_2(t1, a1, t2, a2) \
register t2 _a2 asm ("rsi") = __arg2; \
LOAD_REGS_TYPES_1(t1, a1)
# define ASM_ARGS_2 ASM_ARGS_1, "r" (_a2)
# define LOAD_ARGS_2(a1, a2) \
LOAD_ARGS_TYPES_2 (long int, a1, long int, a2)
# define LOAD_REGS_2 \
LOAD_REGS_TYPES_2 (long int, a1, long int, a2)
# define LOAD_ARGS_TYPES_3(t1, a1, t2, a2, t3, a3) \
t3 __arg3 = (t3) (a3); \
LOAD_ARGS_TYPES_2 (t1, a1, t2, a2)
# define LOAD_REGS_TYPES_3(t1, a1, t2, a2, t3, a3) \
register t3 _a3 asm ("rdx") = __arg3; \
LOAD_REGS_TYPES_2(t1, a1, t2, a2)
# define ASM_ARGS_3 ASM_ARGS_2, "r" (_a3)
# define LOAD_ARGS_3(a1, a2, a3) \
LOAD_ARGS_TYPES_3 (long int, a1, long int, a2, long int, a3)
# define LOAD_REGS_3 \
LOAD_REGS_TYPES_3 (long int, a1, long int, a2, long int, a3)
# define LOAD_ARGS_TYPES_4(t1, a1, t2, a2, t3, a3, t4, a4) \
t4 __arg4 = (t4) (a4); \
LOAD_ARGS_TYPES_3 (t1, a1, t2, a2, t3, a3)
# define LOAD_REGS_TYPES_4(t1, a1, t2, a2, t3, a3, t4, a4) \
register t4 _a4 asm ("r10") = __arg4; \
LOAD_REGS_TYPES_3(t1, a2, t2, a2, t3, a3)
# define ASM_ARGS_4 ASM_ARGS_3, "r" (_a4)
# define LOAD_ARGS_4(a1, a2, a3, a4) \
LOAD_ARGS_TYPES_4 (long int, a1, long int, a2, long int, a3, \
long int, a4)
# define LOAD_REGS_4 \
LOAD_REGS_TYPES_4 (long int, a1, long int, a2, long int, a3, \
long int, a4)
# define LOAD_ARGS_TYPES_5(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5) \
t5 __arg5 = (t5) (a5); \
LOAD_ARGS_TYPES_4 (t1, a1, t2, a2, t3, a3, t4, a4)
# define LOAD_REGS_TYPES_5(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5) \
register t5 _a5 asm ("r8") = __arg5; \
LOAD_REGS_TYPES_4 (t1, a1, t2, a2, t3, a3, t4, a4)
# define ASM_ARGS_5 ASM_ARGS_4, "r" (_a5)
# define LOAD_ARGS_5(a1, a2, a3, a4, a5) \
LOAD_ARGS_TYPES_5 (long int, a1, long int, a2, long int, a3, \
long int, a4, long int, a5)
# define LOAD_REGS_5 \
LOAD_REGS_TYPES_5 (long int, a1, long int, a2, long int, a3, \
long int, a4, long int, a5)
# define LOAD_ARGS_TYPES_6(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5, t6, a6) \
t6 __arg6 = (t6) (a6); \
LOAD_ARGS_TYPES_5 (t1, a1, t2, a2, t3, a3, t4, a4, t5, a5)
# define LOAD_REGS_TYPES_6(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5, t6, a6) \
register t6 _a6 asm ("r9") = __arg6; \
LOAD_REGS_TYPES_5 (t1, a1, t2, a2, t3, a3, t4, a4, t5, a5)
# define ASM_ARGS_6 ASM_ARGS_5, "r" (_a6)
# define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6) \
LOAD_ARGS_TYPES_6 (long int, a1, long int, a2, long int, a3, \
long int, a4, long int, a5, long int, a6)
# define LOAD_REGS_6 \
LOAD_REGS_TYPES_6 (long int, a1, long int, a2, long int, a3, \
long int, a4, long int, a5, long int, a6)
#endif /* __ASSEMBLER__ */
/* Pointer mangling support. */
#ifdef IS_IN_rtld
/* We cannot use the thread descriptor because in ld.so we use setjmp
earlier than the descriptor is initialized. */
# ifdef __ASSEMBLER__
# define PTR_MANGLE(reg) xor __pointer_chk_guard_local(%rip), reg; \
rol $2*LP_SIZE+1, reg
# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
xor __pointer_chk_guard_local(%rip), reg
# else
# define PTR_MANGLE(reg) asm ("xor __pointer_chk_guard_local(%%rip), %0\n" \
"rol $2*" LP_SIZE "+1, %0" \
: "=r" (reg) : "0" (reg))
# define PTR_DEMANGLE(reg) asm ("ror $2*" LP_SIZE "+1, %0\n" \
"xor __pointer_chk_guard_local(%%rip), %0" \
: "=r" (reg) : "0" (reg))
# endif
#else
# ifdef __ASSEMBLER__
# define PTR_MANGLE(reg) xor %fs:POINTER_GUARD, reg; \
rol $2*LP_SIZE+1, reg
# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
xor %fs:POINTER_GUARD, reg
# else
# define PTR_MANGLE(var) asm ("xor %%fs:%c2, %0\n" \
"rol $2*" LP_SIZE "+1, %0" \
: "=r" (var) \
: "0" (var), \
"i" (offsetof (tcbhead_t, \
pointer_guard)))
# define PTR_DEMANGLE(var) asm ("ror $2*" LP_SIZE "+1, %0\n" \
"xor %%fs:%c2, %0" \
: "=r" (var) \
: "0" (var), \
"i" (offsetof (tcbhead_t, \
pointer_guard)))
# endif
#endif
#endif /* linux/x86_64/sysdep.h */
|
