Fix scanf rounding of negative floating-point numbers (bug 23280).
[glibc.git] / sysdeps / unix / sysv / linux / x86_64 / sysdep.h
blob1ef0f742aefb849b234a3695c21f987a2926bd07
1 /* Copyright (C) 2001-2018 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
18 #ifndef _LINUX_X86_64_SYSDEP_H
19 #define _LINUX_X86_64_SYSDEP_H 1
21 /* There is some commonality. */
22 #include <sysdeps/unix/sysv/linux/sysdep.h>
23 #include <sysdeps/unix/x86_64/sysdep.h>
24 #include <tls.h>
26 /* Defines RTLD_PRIVATE_ERRNO. */
27 #include <dl-sysdep.h>
29 /* For Linux we can use the system call table in the header file
30 /usr/include/asm/unistd.h
31 of the kernel. But these symbols do not follow the SYS_* syntax
32 so we have to redefine the `SYS_ify' macro here. */
33 #undef SYS_ify
34 #define SYS_ify(syscall_name) __NR_##syscall_name
36 /* This is a kludge to make syscalls.list find these under the names
37 pread and pwrite, since some kernel headers define those names
38 and some define the *64 names for the same system calls. */
39 #if !defined __NR_pread && defined __NR_pread64
40 # define __NR_pread __NR_pread64
41 #endif
42 #if !defined __NR_pwrite && defined __NR_pwrite64
43 # define __NR_pwrite __NR_pwrite64
44 #endif
46 /* This is to help the old kernel headers where __NR_semtimedop is not
47 available. */
48 #ifndef __NR_semtimedop
49 # define __NR_semtimedop 220
50 #endif
53 #ifdef __ASSEMBLER__
55 /* Linux uses a negative return value to indicate syscall errors,
56 unlike most Unices, which use the condition codes' carry flag.
58 Since version 2.1 the return value of a system call might be
59 negative even if the call succeeded. E.g., the `lseek' system call
60 might return a large offset. Therefore we must not anymore test
61 for < 0, but test for a real error by making sure the value in %eax
62 is a real error number. Linus said he will make sure the no syscall
63 returns a value in -1 .. -4095 as a valid result so we can savely
64 test with -4095. */
66 /* We don't want the label for the error handle to be global when we define
67 it here. */
68 # ifdef PIC
69 # define SYSCALL_ERROR_LABEL 0f
70 # else
71 # define SYSCALL_ERROR_LABEL syscall_error
72 # endif
74 # undef PSEUDO
75 # define PSEUDO(name, syscall_name, args) \
76 .text; \
77 ENTRY (name) \
78 DO_CALL (syscall_name, args); \
79 cmpq $-4095, %rax; \
80 jae SYSCALL_ERROR_LABEL
82 # undef PSEUDO_END
83 # define PSEUDO_END(name) \
84 SYSCALL_ERROR_HANDLER \
85 END (name)
87 # undef PSEUDO_NOERRNO
88 # define PSEUDO_NOERRNO(name, syscall_name, args) \
89 .text; \
90 ENTRY (name) \
91 DO_CALL (syscall_name, args)
93 # undef PSEUDO_END_NOERRNO
94 # define PSEUDO_END_NOERRNO(name) \
95 END (name)
97 # define ret_NOERRNO ret
99 # undef PSEUDO_ERRVAL
100 # define PSEUDO_ERRVAL(name, syscall_name, args) \
101 .text; \
102 ENTRY (name) \
103 DO_CALL (syscall_name, args); \
104 negq %rax
106 # undef PSEUDO_END_ERRVAL
107 # define PSEUDO_END_ERRVAL(name) \
108 END (name)
110 # define ret_ERRVAL ret
112 # if defined PIC && RTLD_PRIVATE_ERRNO
113 # define SYSCALL_SET_ERRNO \
114 lea rtld_errno(%rip), %RCX_LP; \
115 neg %eax; \
116 movl %eax, (%rcx)
117 # else
118 # if IS_IN (libc)
119 # define SYSCALL_ERROR_ERRNO __libc_errno
120 # else
121 # define SYSCALL_ERROR_ERRNO errno
122 # endif
123 # define SYSCALL_SET_ERRNO \
124 movq SYSCALL_ERROR_ERRNO@GOTTPOFF(%rip), %rcx;\
125 neg %eax; \
126 movl %eax, %fs:(%rcx);
127 # endif
129 # ifndef PIC
130 # define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used. */
131 # else
132 # define SYSCALL_ERROR_HANDLER \
133 0: \
134 SYSCALL_SET_ERRNO; \
135 or $-1, %RAX_LP; \
136 ret;
137 # endif /* PIC */
139 /* The Linux/x86-64 kernel expects the system call parameters in
140 registers according to the following table:
142 syscall number rax
143 arg 1 rdi
144 arg 2 rsi
145 arg 3 rdx
146 arg 4 r10
147 arg 5 r8
148 arg 6 r9
150 The Linux kernel uses and destroys internally these registers:
151 return address from
152 syscall rcx
153 eflags from syscall r11
155 Normal function call, including calls to the system call stub
156 functions in the libc, get the first six parameters passed in
157 registers and the seventh parameter and later on the stack. The
158 register use is as follows:
160 system call number in the DO_CALL macro
161 arg 1 rdi
162 arg 2 rsi
163 arg 3 rdx
164 arg 4 rcx
165 arg 5 r8
166 arg 6 r9
168 We have to take care that the stack is aligned to 16 bytes. When
169 called the stack is not aligned since the return address has just
170 been pushed.
173 Syscalls of more than 6 arguments are not supported. */
175 # undef DO_CALL
176 # define DO_CALL(syscall_name, args) \
177 DOARGS_##args \
178 movl $SYS_ify (syscall_name), %eax; \
179 syscall;
181 # define DOARGS_0 /* nothing */
182 # define DOARGS_1 /* nothing */
183 # define DOARGS_2 /* nothing */
184 # define DOARGS_3 /* nothing */
185 # define DOARGS_4 movq %rcx, %r10;
186 # define DOARGS_5 DOARGS_4
187 # define DOARGS_6 DOARGS_5
189 #else /* !__ASSEMBLER__ */
190 /* Define a macro which expands inline into the wrapper code for a system
191 call. */
192 # undef INLINE_SYSCALL
193 # define INLINE_SYSCALL(name, nr, args...) \
194 ({ \
195 unsigned long int resultvar = INTERNAL_SYSCALL (name, , nr, args); \
196 if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (resultvar, ))) \
198 __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, )); \
199 resultvar = (unsigned long int) -1; \
201 (long int) resultvar; })
203 /* Define a macro with explicit types for arguments, which expands inline
204 into the wrapper code for a system call. It should be used when size
205 of any argument > size of long int. */
206 # undef INLINE_SYSCALL_TYPES
207 # define INLINE_SYSCALL_TYPES(name, nr, args...) \
208 ({ \
209 unsigned long int resultvar = INTERNAL_SYSCALL_TYPES (name, , nr, args); \
210 if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (resultvar, ))) \
212 __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, )); \
213 resultvar = (unsigned long int) -1; \
215 (long int) resultvar; })
217 # undef INTERNAL_SYSCALL_DECL
218 # define INTERNAL_SYSCALL_DECL(err) do { } while (0)
220 /* Registers clobbered by syscall. */
221 # define REGISTERS_CLOBBERED_BY_SYSCALL "cc", "r11", "cx"
223 /* Create a variable 'name' based on type 'X' to avoid explicit types.
224 This is mainly used set use 64-bits arguments in x32. */
225 #define TYPEFY(X, name) __typeof__ ((X) - (X)) name
226 /* Explicit cast the argument to avoid integer from pointer warning on
227 x32. */
228 #define ARGIFY(X) ((__typeof__ ((X) - (X))) (X))
230 #undef INTERNAL_SYSCALL
231 #define INTERNAL_SYSCALL(name, err, nr, args...) \
232 internal_syscall##nr (SYS_ify (name), err, args)
234 #undef INTERNAL_SYSCALL_NCS
235 #define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
236 internal_syscall##nr (number, err, args)
238 #undef internal_syscall0
239 #define internal_syscall0(number, err, dummy...) \
240 ({ \
241 unsigned long int resultvar; \
242 asm volatile ( \
243 "syscall\n\t" \
244 : "=a" (resultvar) \
245 : "0" (number) \
246 : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
247 (long int) resultvar; \
250 #undef internal_syscall1
251 #define internal_syscall1(number, err, arg1) \
252 ({ \
253 unsigned long int resultvar; \
254 TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
255 register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
256 asm volatile ( \
257 "syscall\n\t" \
258 : "=a" (resultvar) \
259 : "0" (number), "r" (_a1) \
260 : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
261 (long int) resultvar; \
264 #undef internal_syscall2
265 #define internal_syscall2(number, err, arg1, arg2) \
266 ({ \
267 unsigned long int resultvar; \
268 TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
269 TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
270 register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
271 register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
272 asm volatile ( \
273 "syscall\n\t" \
274 : "=a" (resultvar) \
275 : "0" (number), "r" (_a1), "r" (_a2) \
276 : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
277 (long int) resultvar; \
280 #undef internal_syscall3
281 #define internal_syscall3(number, err, arg1, arg2, arg3) \
282 ({ \
283 unsigned long int resultvar; \
284 TYPEFY (arg3, __arg3) = ARGIFY (arg3); \
285 TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
286 TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
287 register TYPEFY (arg3, _a3) asm ("rdx") = __arg3; \
288 register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
289 register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
290 asm volatile ( \
291 "syscall\n\t" \
292 : "=a" (resultvar) \
293 : "0" (number), "r" (_a1), "r" (_a2), "r" (_a3) \
294 : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
295 (long int) resultvar; \
298 #undef internal_syscall4
299 #define internal_syscall4(number, err, arg1, arg2, arg3, arg4) \
300 ({ \
301 unsigned long int resultvar; \
302 TYPEFY (arg4, __arg4) = ARGIFY (arg4); \
303 TYPEFY (arg3, __arg3) = ARGIFY (arg3); \
304 TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
305 TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
306 register TYPEFY (arg4, _a4) asm ("r10") = __arg4; \
307 register TYPEFY (arg3, _a3) asm ("rdx") = __arg3; \
308 register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
309 register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
310 asm volatile ( \
311 "syscall\n\t" \
312 : "=a" (resultvar) \
313 : "0" (number), "r" (_a1), "r" (_a2), "r" (_a3), "r" (_a4) \
314 : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
315 (long int) resultvar; \
318 #undef internal_syscall5
319 #define internal_syscall5(number, err, arg1, arg2, arg3, arg4, arg5) \
320 ({ \
321 unsigned long int resultvar; \
322 TYPEFY (arg5, __arg5) = ARGIFY (arg5); \
323 TYPEFY (arg4, __arg4) = ARGIFY (arg4); \
324 TYPEFY (arg3, __arg3) = ARGIFY (arg3); \
325 TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
326 TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
327 register TYPEFY (arg5, _a5) asm ("r8") = __arg5; \
328 register TYPEFY (arg4, _a4) asm ("r10") = __arg4; \
329 register TYPEFY (arg3, _a3) asm ("rdx") = __arg3; \
330 register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
331 register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
332 asm volatile ( \
333 "syscall\n\t" \
334 : "=a" (resultvar) \
335 : "0" (number), "r" (_a1), "r" (_a2), "r" (_a3), "r" (_a4), \
336 "r" (_a5) \
337 : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
338 (long int) resultvar; \
341 #undef internal_syscall6
342 #define internal_syscall6(number, err, arg1, arg2, arg3, arg4, arg5, arg6) \
343 ({ \
344 unsigned long int resultvar; \
345 TYPEFY (arg6, __arg6) = ARGIFY (arg6); \
346 TYPEFY (arg5, __arg5) = ARGIFY (arg5); \
347 TYPEFY (arg4, __arg4) = ARGIFY (arg4); \
348 TYPEFY (arg3, __arg3) = ARGIFY (arg3); \
349 TYPEFY (arg2, __arg2) = ARGIFY (arg2); \
350 TYPEFY (arg1, __arg1) = ARGIFY (arg1); \
351 register TYPEFY (arg6, _a6) asm ("r9") = __arg6; \
352 register TYPEFY (arg5, _a5) asm ("r8") = __arg5; \
353 register TYPEFY (arg4, _a4) asm ("r10") = __arg4; \
354 register TYPEFY (arg3, _a3) asm ("rdx") = __arg3; \
355 register TYPEFY (arg2, _a2) asm ("rsi") = __arg2; \
356 register TYPEFY (arg1, _a1) asm ("rdi") = __arg1; \
357 asm volatile ( \
358 "syscall\n\t" \
359 : "=a" (resultvar) \
360 : "0" (number), "r" (_a1), "r" (_a2), "r" (_a3), "r" (_a4), \
361 "r" (_a5), "r" (_a6) \
362 : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
363 (long int) resultvar; \
366 # undef INTERNAL_SYSCALL_ERROR_P
367 # define INTERNAL_SYSCALL_ERROR_P(val, err) \
368 ((unsigned long int) (long int) (val) >= -4095L)
370 # undef INTERNAL_SYSCALL_ERRNO
371 # define INTERNAL_SYSCALL_ERRNO(val, err) (-(val))
373 /* List of system calls which are supported as vsyscalls. */
374 # define HAVE_CLOCK_GETTIME_VSYSCALL 1
375 # define HAVE_GETTIMEOFDAY_VSYSCALL 1
376 # define HAVE_GETCPU_VSYSCALL 1
378 # define SINGLE_THREAD_BY_GLOBAL 1
380 #endif /* __ASSEMBLER__ */
383 /* Pointer mangling support. */
384 #if IS_IN (rtld)
385 /* We cannot use the thread descriptor because in ld.so we use setjmp
386 earlier than the descriptor is initialized. */
387 # ifdef __ASSEMBLER__
388 # define PTR_MANGLE(reg) xor __pointer_chk_guard_local(%rip), reg; \
389 rol $2*LP_SIZE+1, reg
390 # define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
391 xor __pointer_chk_guard_local(%rip), reg
392 # else
393 # define PTR_MANGLE(reg) asm ("xor __pointer_chk_guard_local(%%rip), %0\n" \
394 "rol $2*" LP_SIZE "+1, %0" \
395 : "=r" (reg) : "0" (reg))
396 # define PTR_DEMANGLE(reg) asm ("ror $2*" LP_SIZE "+1, %0\n" \
397 "xor __pointer_chk_guard_local(%%rip), %0" \
398 : "=r" (reg) : "0" (reg))
399 # endif
400 #else
401 # ifdef __ASSEMBLER__
402 # define PTR_MANGLE(reg) xor %fs:POINTER_GUARD, reg; \
403 rol $2*LP_SIZE+1, reg
404 # define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
405 xor %fs:POINTER_GUARD, reg
406 # else
407 # define PTR_MANGLE(var) asm ("xor %%fs:%c2, %0\n" \
408 "rol $2*" LP_SIZE "+1, %0" \
409 : "=r" (var) \
410 : "0" (var), \
411 "i" (offsetof (tcbhead_t, \
412 pointer_guard)))
413 # define PTR_DEMANGLE(var) asm ("ror $2*" LP_SIZE "+1, %0\n" \
414 "xor %%fs:%c2, %0" \
415 : "=r" (var) \
416 : "0" (var), \
417 "i" (offsetof (tcbhead_t, \
418 pointer_guard)))
419 # endif
420 #endif
422 /* How to pass the off{64}_t argument on p{readv,writev}{64}. */
423 #undef LO_HI_LONG
424 #define LO_HI_LONG(val) (val), 0
426 #endif /* linux/x86_64/sysdep.h */