sysdeps/unix/sysv/linux/x86_64/sysdep.h

   1 /* Copyright (C) 2001-2005, 2007, 2011 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   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.
   8
   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.
  13
  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/>.  */
  17
  18 #ifndef _LINUX_X86_64_SYSDEP_H
  19 #define _LINUX_X86_64_SYSDEP_H 1
  20
  21 /* There is some commonality.  */
  22 #include <sysdeps/unix/x86_64/sysdep.h>
  23 #include <bp-sym.h>
  24 #include <bp-asm.h>
  25 #include <tls.h>
  26
  27 #ifdef IS_IN_rtld
  28 # include <dl-sysdep.h>         /* Defines RTLD_PRIVATE_ERRNO.  */
  29 #endif
  30
  31 /* For Linux we can use the system call table in the header file
  32         /usr/include/asm/unistd.h
  33    of the kernel.  But these symbols do not follow the SYS_* syntax
  34    so we have to redefine the `SYS_ify' macro here.  */
  35 #undef SYS_ify
  36 #define SYS_ify(syscall_name)   __NR_##syscall_name
  37
  38 /* This is a kludge to make syscalls.list find these under the names
  39    pread and pwrite, since some kernel headers define those names
  40    and some define the *64 names for the same system calls.  */
  41 #if !defined __NR_pread && defined __NR_pread64
  42 # define __NR_pread __NR_pread64
  43 #endif
  44 #if !defined __NR_pwrite && defined __NR_pwrite64
  45 # define __NR_pwrite __NR_pwrite64
  46 #endif
  47
  48 /* This is to help the old kernel headers where __NR_semtimedop is not
  49    available.  */
  50 #ifndef __NR_semtimedop
  51 # define __NR_semtimedop 220
  52 #endif
  53
  54
  55 #ifdef __ASSEMBLER__
  56
  57 /* Linux uses a negative return value to indicate syscall errors,
  58    unlike most Unices, which use the condition codes' carry flag.
  59
  60    Since version 2.1 the return value of a system call might be
  61    negative even if the call succeeded.  E.g., the `lseek' system call
  62    might return a large offset.  Therefore we must not anymore test
  63    for < 0, but test for a real error by making sure the value in %eax
  64    is a real error number.  Linus said he will make sure the no syscall
  65    returns a value in -1 .. -4095 as a valid result so we can savely
  66    test with -4095.  */
  67
  68 /* We don't want the label for the error handle to be global when we define
  69    it here.  */
  70 # ifdef PIC
  71 #  define SYSCALL_ERROR_LABEL 0f
  72 # else
  73 #  define SYSCALL_ERROR_LABEL syscall_error
  74 # endif
  75
  76 # undef PSEUDO
  77 # define PSEUDO(name, syscall_name, args)                                     \
  78   .text;                                                                      \
  79   ENTRY (name)                                                                \
  80     DO_CALL (syscall_name, args);                                             \
  81     cmpq $-4095, %rax;                                                        \
  82     jae SYSCALL_ERROR_LABEL;                                                  \
  83   L(pseudo_end):
  84
  85 # undef PSEUDO_END
  86 # define PSEUDO_END(name)                                                     \
  87   SYSCALL_ERROR_HANDLER                                                       \
  88   END (name)
  89
  90 # undef PSEUDO_NOERRNO
  91 # define PSEUDO_NOERRNO(name, syscall_name, args) \
  92   .text;                                                                      \
  93   ENTRY (name)                                                                \
  94     DO_CALL (syscall_name, args)
  95
  96 # undef PSEUDO_END_NOERRNO
  97 # define PSEUDO_END_NOERRNO(name) \
  98   END (name)
  99
 100 # define ret_NOERRNO ret
 101
 102 # undef PSEUDO_ERRVAL
 103 # define PSEUDO_ERRVAL(name, syscall_name, args) \
 104   .text;                                                                      \
 105   ENTRY (name)                                                                \
 106     DO_CALL (syscall_name, args);                                             \
 107     negq %rax
 108
 109 # undef PSEUDO_END_ERRVAL
 110 # define PSEUDO_END_ERRVAL(name) \
 111   END (name)
 112
 113 # define ret_ERRVAL ret
 114
 115 # ifndef PIC
 116 #  define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used.  */
 117 # elif RTLD_PRIVATE_ERRNO
 118 #  define SYSCALL_ERROR_HANDLER                 \
 119 0:                                              \
 120   leaq rtld_errno(%rip), %rcx;                  \
 121   xorl %edx, %edx;                              \
 122   subq %rax, %rdx;                              \
 123   movl %edx, (%rcx);                            \
 124   orq $-1, %rax;                                \
 125   jmp L(pseudo_end);
 126 # else
 127 #  ifndef NOT_IN_libc
 128 #   define SYSCALL_ERROR_ERRNO __libc_errno
 129 #  else
 130 #   define SYSCALL_ERROR_ERRNO errno
 131 #  endif
 132 #  define SYSCALL_ERROR_HANDLER                 \
 133 0:                                              \
 134   movq SYSCALL_ERROR_ERRNO@GOTTPOFF(%rip), %rcx;\
 135   xorl %edx, %edx;                              \
 136   subq %rax, %rdx;                              \
 137   movl %edx, %fs:(%rcx);                        \
 138   orq $-1, %rax;                                \
 139   jmp L(pseudo_end);
 140 # endif /* PIC */
 141
 142 /* The Linux/x86-64 kernel expects the system call parameters in
 143    registers according to the following table:
 144
 145     syscall number      rax
 146     arg 1               rdi
 147     arg 2               rsi
 148     arg 3               rdx
 149     arg 4               r10
 150     arg 5               r8
 151     arg 6               r9
 152
 153     The Linux kernel uses and destroys internally these registers:
 154     return address from
 155     syscall             rcx
 156     eflags from syscall r11
 157
 158     Normal function call, including calls to the system call stub
 159     functions in the libc, get the first six parameters passed in
 160     registers and the seventh parameter and later on the stack.  The
 161     register use is as follows:
 162
 163      system call number in the DO_CALL macro
 164      arg 1              rdi
 165      arg 2              rsi
 166      arg 3              rdx
 167      arg 4              rcx
 168      arg 5              r8
 169      arg 6              r9
 170
 171     We have to take care that the stack is aligned to 16 bytes.  When
 172     called the stack is not aligned since the return address has just
 173     been pushed.
 174
 175
 176     Syscalls of more than 6 arguments are not supported.  */
 177
 178 # undef DO_CALL
 179 # define DO_CALL(syscall_name, args)            \
 180     DOARGS_##args                               \
 181     movl $SYS_ify (syscall_name), %eax;         \
 182     syscall;
 183
 184 # define DOARGS_0 /* nothing */
 185 # define DOARGS_1 /* nothing */
 186 # define DOARGS_2 /* nothing */
 187 # define DOARGS_3 /* nothing */
 188 # define DOARGS_4 movq %rcx, %r10;
 189 # define DOARGS_5 DOARGS_4
 190 # define DOARGS_6 DOARGS_5
 191
 192 #else   /* !__ASSEMBLER__ */
 193 /* Define a macro which expands inline into the wrapper code for a system
 194    call.  */
 195 # undef INLINE_SYSCALL
 196 # define INLINE_SYSCALL(name, nr, args...) \
 197   ({                                                                          \
 198     unsigned long int resultvar = INTERNAL_SYSCALL (name, , nr, args);        \
 199     if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (resultvar, ), 0))         \
 200       {                                                                       \
 201         __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, ));                   \
 202         resultvar = (unsigned long int) -1;                                   \
 203       }                                                                       \
 204     (long int) resultvar; })
 205
 206 # undef INTERNAL_SYSCALL_DECL
 207 # define INTERNAL_SYSCALL_DECL(err) do { } while (0)
 208
 209 # define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
 210   ({                                                                          \
 211     unsigned long int resultvar;                                              \
 212     LOAD_ARGS_##nr (args)                                                     \
 213     LOAD_REGS_##nr                                                            \
 214     asm volatile (                                                            \
 215     "syscall\n\t"                                                             \
 216     : "=a" (resultvar)                                                        \
 217     : "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx");                \
 218     (long int) resultvar; })
 219 # undef INTERNAL_SYSCALL
 220 # define INTERNAL_SYSCALL(name, err, nr, args...) \
 221   INTERNAL_SYSCALL_NCS (__NR_##name, err, nr, ##args)
 222
 223 # undef INTERNAL_SYSCALL_ERROR_P
 224 # define INTERNAL_SYSCALL_ERROR_P(val, err) \
 225   ((unsigned long int) (long int) (val) >= -4095L)
 226
 227 # undef INTERNAL_SYSCALL_ERRNO
 228 # define INTERNAL_SYSCALL_ERRNO(val, err)       (-(val))
 229
 230 # ifdef SHARED
 231 #  define INLINE_VSYSCALL(name, nr, args...) \
 232   ({                                                                          \
 233     __label__ out;                                                            \
 234     __label__ iserr;                                                          \
 235     INTERNAL_SYSCALL_DECL (sc_err);                                           \
 236     long int sc_ret;                                                          \
 237                                                                               \
 238     __typeof (__vdso_##name) vdsop = __vdso_##name;                           \
 239     PTR_DEMANGLE (vdsop);                                                     \
 240     if (vdsop != NULL)                                                        \
 241       {                                                                       \
 242         sc_ret = vdsop (args);                                                \
 243         if (!INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err))                       \
 244           goto out;                                                           \
 245         if (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err) != ENOSYS)                \
 246           goto iserr;                                                         \
 247       }                                                                       \
 248                                                                               \
 249     sc_ret = INTERNAL_SYSCALL (name, sc_err, nr, ##args);                     \
 250     if (INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err))                            \
 251       {                                                                       \
 252       iserr:                                                                  \
 253         __set_errno (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err));                \
 254         sc_ret = -1L;                                                         \
 255       }                                                                       \
 256   out:                                                                        \
 257     sc_ret;                                                                   \
 258   })
 259 #  define INTERNAL_VSYSCALL(name, err, nr, args...) \
 260   ({                                                                          \
 261     __label__ out;                                                            \
 262     long int v_ret;                                                           \
 263                                                                               \
 264     __typeof (__vdso_##name) vdsop = __vdso_##name;                           \
 265     PTR_DEMANGLE (vdsop);                                                     \
 266     if (vdsop != NULL)                                                        \
 267       {                                                                       \
 268         v_ret = vdsop (args);                                                 \
 269         if (!INTERNAL_SYSCALL_ERROR_P (v_ret, err)                            \
 270             || INTERNAL_SYSCALL_ERRNO (v_ret, err) != ENOSYS)                 \
 271           goto out;                                                           \
 272       }                                                                       \
 273     v_ret = INTERNAL_SYSCALL (name, err, nr, ##args);                         \
 274   out:                                                                        \
 275     v_ret;                                                                    \
 276   })
 277
 278 # else
 279 #  define INLINE_VSYSCALL(name, nr, args...) \
 280   INLINE_SYSCALL (name, nr, ##args)
 281 #  define INTERNAL_VSYSCALL(name, err, nr, args...) \
 282   INTERNAL_SYSCALL (name, err, nr, ##args)
 283 # endif
 284
 285 # define LOAD_ARGS_0()
 286 # define LOAD_REGS_0
 287 # define ASM_ARGS_0
 288
 289 # define LOAD_ARGS_1(a1)                                \
 290   long int __arg1 = (long int) (a1);                    \
 291   LOAD_ARGS_0 ()
 292 # define LOAD_REGS_1                                    \
 293   register long int _a1 asm ("rdi") = __arg1;           \
 294   LOAD_REGS_0
 295 # define ASM_ARGS_1     ASM_ARGS_0, "r" (_a1)
 296
 297 # define LOAD_ARGS_2(a1, a2)                            \
 298   long int __arg2 = (long int) (a2);                    \
 299   LOAD_ARGS_1 (a1)
 300 # define LOAD_REGS_2                                    \
 301   register long int _a2 asm ("rsi") = __arg2;           \
 302   LOAD_REGS_1
 303 # define ASM_ARGS_2     ASM_ARGS_1, "r" (_a2)
 304
 305 # define LOAD_ARGS_3(a1, a2, a3)                        \
 306   long int __arg3 = (long int) (a3);                    \
 307   LOAD_ARGS_2 (a1, a2)
 308 # define LOAD_REGS_3                                    \
 309   register long int _a3 asm ("rdx") = __arg3;           \
 310   LOAD_REGS_2
 311 # define ASM_ARGS_3     ASM_ARGS_2, "r" (_a3)
 312
 313 # define LOAD_ARGS_4(a1, a2, a3, a4)                    \
 314   long int __arg4 = (long int) (a4);                    \
 315   LOAD_ARGS_3 (a1, a2, a3)
 316 # define LOAD_REGS_4                                    \
 317   register long int _a4 asm ("r10") = __arg4;           \
 318   LOAD_REGS_3
 319 # define ASM_ARGS_4     ASM_ARGS_3, "r" (_a4)
 320
 321 # define LOAD_ARGS_5(a1, a2, a3, a4, a5)                \
 322   long int __arg5 = (long int) (a5);                    \
 323   LOAD_ARGS_4 (a1, a2, a3, a4)
 324 # define LOAD_REGS_5                                    \
 325   register long int _a5 asm ("r8") = __arg5;            \
 326   LOAD_REGS_4
 327 # define ASM_ARGS_5     ASM_ARGS_4, "r" (_a5)
 328
 329 # define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6)            \
 330   long int __arg6 = (long int) (a6);                    \
 331   LOAD_ARGS_5 (a1, a2, a3, a4, a5)
 332 # define LOAD_REGS_6                                    \
 333   register long int _a6 asm ("r9") = __arg6;            \
 334   LOAD_REGS_5
 335 # define ASM_ARGS_6     ASM_ARGS_5, "r" (_a6)
 336
 337 #endif  /* __ASSEMBLER__ */
 338
 339
 340 /* Pointer mangling support.  */
 341 #if defined NOT_IN_libc && defined IS_IN_rtld
 342 /* We cannot use the thread descriptor because in ld.so we use setjmp
 343    earlier than the descriptor is initialized.  */
 344 # ifdef __ASSEMBLER__
 345 #  define PTR_MANGLE(reg)       xorq __pointer_chk_guard_local(%rip), reg;    \
 346                                 rolq $17, reg
 347 #  define PTR_DEMANGLE(reg)     rorq $17, reg;                                \
 348                                 xorq __pointer_chk_guard_local(%rip), reg
 349 # else
 350 #  define PTR_MANGLE(reg)       asm ("xorq __pointer_chk_guard_local(%%rip), %0\n" \
 351                                      "rolq $17, %0"                           \
 352                                      : "=r" (reg) : "0" (reg))
 353 #  define PTR_DEMANGLE(reg)     asm ("rorq $17, %0\n"                         \
 354                                      "xorq __pointer_chk_guard_local(%%rip), %0" \
 355                                      : "=r" (reg) : "0" (reg))
 356 # endif
 357 #else
 358 # ifdef __ASSEMBLER__
 359 #  define PTR_MANGLE(reg)       xorq %fs:POINTER_GUARD, reg;                  \
 360                                 rolq $17, reg
 361 #  define PTR_DEMANGLE(reg)     rorq $17, reg;                                \
 362                                 xorq %fs:POINTER_GUARD, reg
 363 # else
 364 #  define PTR_MANGLE(var)       asm ("xorq %%fs:%c2, %0\n"                    \
 365                                      "rolq $17, %0"                           \
 366                                      : "=r" (var)                             \
 367                                      : "0" (var),                             \
 368                                        "i" (offsetof (tcbhead_t,              \
 369                                                       pointer_guard)))
 370 #  define PTR_DEMANGLE(var)     asm ("rorq $17, %0\n"                         \
 371                                      "xorq %%fs:%c2, %0"                      \
 372                                      : "=r" (var)                             \
 373                                      : "0" (var),                             \
 374                                        "i" (offsetof (tcbhead_t,              \
 375                                                       pointer_guard)))
 376 # endif
 377 #endif
 378
 379 #endif /* linux/x86_64/sysdep.h */