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

   1 /* Copyright (C) 2001-2005, 2007 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #ifndef _LINUX_X86_64_SYSDEP_H
  20 #define _LINUX_X86_64_SYSDEP_H 1
  21
  22 /* There is some commonality.  */
  23 #include <sysdeps/unix/x86_64/sysdep.h>
  24 #include <bp-sym.h>
  25 #include <bp-asm.h>
  26 #include <tls.h>
  27
  28 #ifdef IS_IN_rtld
  29 # include <dl-sysdep.h>         /* Defines RTLD_PRIVATE_ERRNO.  */
  30 #endif
  31
  32 /* For Linux we can use the system call table in the header file
  33         /usr/include/asm/unistd.h
  34    of the kernel.  But these symbols do not follow the SYS_* syntax
  35    so we have to redefine the `SYS_ify' macro here.  */
  36 #undef SYS_ify
  37 #define SYS_ify(syscall_name)   __NR_##syscall_name
  38
  39 /* This is a kludge to make syscalls.list find these under the names
  40    pread and pwrite, since some kernel headers define those names
  41    and some define the *64 names for the same system calls.  */
  42 #if !defined __NR_pread && defined __NR_pread64
  43 # define __NR_pread __NR_pread64
  44 #endif
  45 #if !defined __NR_pwrite && defined __NR_pwrite64
  46 # define __NR_pwrite __NR_pwrite64
  47 #endif
  48
  49 /* This is to help the old kernel headers where __NR_semtimedop is not
  50    available.  */
  51 #ifndef __NR_semtimedop
  52 # define __NR_semtimedop 220
  53 #endif
  54
  55
  56 #ifdef __ASSEMBLER__
  57
  58 /* Linux uses a negative return value to indicate syscall errors,
  59    unlike most Unices, which use the condition codes' carry flag.
  60
  61    Since version 2.1 the return value of a system call might be
  62    negative even if the call succeeded.  E.g., the `lseek' system call
  63    might return a large offset.  Therefore we must not anymore test
  64    for < 0, but test for a real error by making sure the value in %eax
  65    is a real error number.  Linus said he will make sure the no syscall
  66    returns a value in -1 .. -4095 as a valid result so we can savely
  67    test with -4095.  */
  68
  69 /* We don't want the label for the error handle to be global when we define
  70    it here.  */
  71 # ifdef PIC
  72 #  define SYSCALL_ERROR_LABEL 0f
  73 # else
  74 #  define SYSCALL_ERROR_LABEL syscall_error
  75 # endif
  76
  77 # undef PSEUDO
  78 # define PSEUDO(name, syscall_name, args)                                     \
  79   .text;                                                                      \
  80   ENTRY (name)                                                                \
  81     DO_CALL (syscall_name, args);                                             \
  82     cmpq $-4095, %rax;                                                        \
  83     jae SYSCALL_ERROR_LABEL;                                                  \
  84   L(pseudo_end):
  85
  86 # undef PSEUDO_END
  87 # define PSEUDO_END(name)                                                     \
  88   SYSCALL_ERROR_HANDLER                                                       \
  89   END (name)
  90
  91 # undef PSEUDO_NOERRNO
  92 # define PSEUDO_NOERRNO(name, syscall_name, args) \
  93   .text;                                                                      \
  94   ENTRY (name)                                                                \
  95     DO_CALL (syscall_name, args)
  96
  97 # undef PSEUDO_END_NOERRNO
  98 # define PSEUDO_END_NOERRNO(name) \
  99   END (name)
 100
 101 # define ret_NOERRNO ret
 102
 103 # undef PSEUDO_ERRVAL
 104 # define PSEUDO_ERRVAL(name, syscall_name, args) \
 105   .text;                                                                      \
 106   ENTRY (name)                                                                \
 107     DO_CALL (syscall_name, args);                                             \
 108     negq %rax
 109
 110 # undef PSEUDO_END_ERRVAL
 111 # define PSEUDO_END_ERRVAL(name) \
 112   END (name)
 113
 114 # define ret_ERRVAL ret
 115
 116 # ifndef PIC
 117 #  define SYSCALL_ERROR_HANDLER /* Nothing here; code in sysdep.S is used.  */
 118 # elif RTLD_PRIVATE_ERRNO
 119 #  define SYSCALL_ERROR_HANDLER                 \
 120 0:                                              \
 121   leaq rtld_errno(%rip), %rcx;                  \
 122   xorl %edx, %edx;                              \
 123   subq %rax, %rdx;                              \
 124   movl %edx, (%rcx);                            \
 125   orq $-1, %rax;                                \
 126   jmp L(pseudo_end);
 127 # elif USE___THREAD
 128 #  ifndef NOT_IN_libc
 129 #   define SYSCALL_ERROR_ERRNO __libc_errno
 130 #  else
 131 #   define SYSCALL_ERROR_ERRNO errno
 132 #  endif
 133 #  define SYSCALL_ERROR_HANDLER                 \
 134 0:                                              \
 135   movq SYSCALL_ERROR_ERRNO@GOTTPOFF(%rip), %rcx;\
 136   xorl %edx, %edx;                              \
 137   subq %rax, %rdx;                              \
 138   movl %edx, %fs:(%rcx);                        \
 139   orq $-1, %rax;                                \
 140   jmp L(pseudo_end);
 141 # elif defined _LIBC_REENTRANT
 142 /* Store (- %rax) into errno through the GOT.
 143    Note that errno occupies only 4 bytes.  */
 144 #  define SYSCALL_ERROR_HANDLER                 \
 145 0:                                              \
 146   xorl %edx, %edx;                              \
 147   subq %rax, %rdx;                              \
 148   pushq %rdx;                                   \
 149   cfi_adjust_cfa_offset(8);                     \
 150   PUSH_ERRNO_LOCATION_RETURN;                   \
 151   call BP_SYM (__errno_location)@PLT;           \
 152   POP_ERRNO_LOCATION_RETURN;                    \
 153   popq %rdx;                                    \
 154   cfi_adjust_cfa_offset(-8);                    \
 155   movl %edx, (%rax);                            \
 156   orq $-1, %rax;                                \
 157   jmp L(pseudo_end);
 158
 159 /* A quick note: it is assumed that the call to `__errno_location' does
 160    not modify the stack!  */
 161 # else /* Not _LIBC_REENTRANT.  */
 162 #  define SYSCALL_ERROR_HANDLER                 \
 163 0:movq errno@GOTPCREL(%RIP), %rcx;              \
 164   xorl %edx, %edx;                              \
 165   subq %rax, %rdx;                              \
 166   movl %edx, (%rcx);                            \
 167   orq $-1, %rax;                                \
 168   jmp L(pseudo_end);
 169 # endif /* PIC */
 170
 171 /* The Linux/x86-64 kernel expects the system call parameters in
 172    registers according to the following table:
 173
 174     syscall number      rax
 175     arg 1               rdi
 176     arg 2               rsi
 177     arg 3               rdx
 178     arg 4               r10
 179     arg 5               r8
 180     arg 6               r9
 181
 182     The Linux kernel uses and destroys internally these registers:
 183     return address from
 184     syscall             rcx
 185     eflags from syscall r11
 186
 187     Normal function call, including calls to the system call stub
 188     functions in the libc, get the first six parameters passed in
 189     registers and the seventh parameter and later on the stack.  The
 190     register use is as follows:
 191
 192      system call number in the DO_CALL macro
 193      arg 1              rdi
 194      arg 2              rsi
 195      arg 3              rdx
 196      arg 4              rcx
 197      arg 5              r8
 198      arg 6              r9
 199
 200     We have to take care that the stack is aligned to 16 bytes.  When
 201     called the stack is not aligned since the return address has just
 202     been pushed.
 203
 204
 205     Syscalls of more than 6 arguments are not supported.  */
 206
 207 # undef DO_CALL
 208 # define DO_CALL(syscall_name, args)            \
 209     DOARGS_##args                               \
 210     movl $SYS_ify (syscall_name), %eax;         \
 211     syscall;
 212
 213 # define DOARGS_0 /* nothing */
 214 # define DOARGS_1 /* nothing */
 215 # define DOARGS_2 /* nothing */
 216 # define DOARGS_3 /* nothing */
 217 # define DOARGS_4 movq %rcx, %r10;
 218 # define DOARGS_5 DOARGS_4
 219 # define DOARGS_6 DOARGS_5
 220
 221 #else   /* !__ASSEMBLER__ */
 222 /* Define a macro which expands inline into the wrapper code for a system
 223    call.  */
 224 # undef INLINE_SYSCALL
 225 # define INLINE_SYSCALL(name, nr, args...) \
 226   ({                                                                          \
 227     unsigned long int resultvar = INTERNAL_SYSCALL (name, , nr, args);        \
 228     if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (resultvar, ), 0))         \
 229       {                                                                       \
 230         __set_errno (INTERNAL_SYSCALL_ERRNO (resultvar, ));                   \
 231         resultvar = (unsigned long int) -1;                                   \
 232       }                                                                       \
 233     (long int) resultvar; })
 234
 235 # undef INTERNAL_SYSCALL_DECL
 236 # define INTERNAL_SYSCALL_DECL(err) do { } while (0)
 237
 238 # define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
 239   ({                                                                          \
 240     unsigned long int resultvar;                                              \
 241     LOAD_ARGS_##nr (args)                                                     \
 242     LOAD_REGS_##nr                                                            \
 243     asm volatile (                                                            \
 244     "syscall\n\t"                                                             \
 245     : "=a" (resultvar)                                                        \
 246     : "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx");                \
 247     (long int) resultvar; })
 248 # undef INTERNAL_SYSCALL
 249 # define INTERNAL_SYSCALL(name, err, nr, args...) \
 250   INTERNAL_SYSCALL_NCS (__NR_##name, err, nr, ##args)
 251
 252 # undef INTERNAL_SYSCALL_ERROR_P
 253 # define INTERNAL_SYSCALL_ERROR_P(val, err) \
 254   ((unsigned long int) (long int) (val) >= -4095L)
 255
 256 # undef INTERNAL_SYSCALL_ERRNO
 257 # define INTERNAL_SYSCALL_ERRNO(val, err)       (-(val))
 258
 259 # ifdef SHARED
 260 #  define INLINE_VSYSCALL(name, nr, args...) \
 261   ({                                                                          \
 262     __label__ out;                                                            \
 263     __label__ iserr;                                                          \
 264     INTERNAL_SYSCALL_DECL (sc_err);                                           \
 265     long int sc_ret;                                                          \
 266                                                                               \
 267     __typeof (__vdso_##name) vdsop = __vdso_##name;                           \
 268     PTR_DEMANGLE (vdsop);                                                     \
 269     if (vdsop != NULL)                                                        \
 270       {                                                                       \
 271         sc_ret = vdsop (args);                                                \
 272         if (!INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err))                       \
 273           goto out;                                                           \
 274         if (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err) != ENOSYS)                \
 275           goto iserr;                                                         \
 276       }                                                                       \
 277                                                                               \
 278     sc_ret = INTERNAL_SYSCALL (name, sc_err, nr, ##args);                     \
 279     if (INTERNAL_SYSCALL_ERROR_P (sc_ret, sc_err))                            \
 280       {                                                                       \
 281       iserr:                                                                  \
 282         __set_errno (INTERNAL_SYSCALL_ERRNO (sc_ret, sc_err));                \
 283         sc_ret = -1L;                                                         \
 284       }                                                                       \
 285   out:                                                                        \
 286     sc_ret;                                                                   \
 287   })
 288 #  define INTERNAL_VSYSCALL(name, err, nr, args...) \
 289   ({                                                                          \
 290     __label__ out;                                                            \
 291     long int v_ret;                                                           \
 292                                                                               \
 293     __typeof (__vdso_##name) vdsop = __vdso_##name;                           \
 294     PTR_DEMANGLE (vdsop);                                                     \
 295     if (vdsop != NULL)                                                        \
 296       {                                                                       \
 297         v_ret = vdsop (args);                                                 \
 298         if (!INTERNAL_SYSCALL_ERROR_P (v_ret, err)                            \
 299             || INTERNAL_SYSCALL_ERRNO (v_ret, err) != ENOSYS)                 \
 300           goto out;                                                           \
 301       }                                                                       \
 302     v_ret = INTERNAL_SYSCALL (name, err, nr, ##args);                         \
 303   out:                                                                        \
 304     v_ret;                                                                    \
 305   })
 306
 307 /* List of system calls which are supported as vsyscalls.  */
 308 #  define HAVE_CLOCK_GETTIME_VSYSCALL   1
 309
 310 # else
 311 #  define INLINE_VSYSCALL(name, nr, args...) \
 312   INLINE_SYSCALL (name, nr, ##args)
 313 #  define INTERNAL_VSYSCALL(name, err, nr, args...) \
 314   INTERNAL_SYSCALL (name, err, nr, ##args)
 315 # endif
 316
 317 # define LOAD_ARGS_0()
 318 # define LOAD_REGS_0
 319 # define ASM_ARGS_0
 320
 321 # define LOAD_ARGS_1(a1)                                \
 322   long int __arg1 = (long int) (a1);                    \
 323   LOAD_ARGS_0 ()
 324 # define LOAD_REGS_1                                    \
 325   register long int _a1 asm ("rdi") = __arg1;           \
 326   LOAD_REGS_0
 327 # define ASM_ARGS_1     ASM_ARGS_0, "r" (_a1)
 328
 329 # define LOAD_ARGS_2(a1, a2)                            \
 330   long int __arg2 = (long int) (a2);                    \
 331   LOAD_ARGS_1 (a1)
 332 # define LOAD_REGS_2                                    \
 333   register long int _a2 asm ("rsi") = __arg2;           \
 334   LOAD_REGS_1
 335 # define ASM_ARGS_2     ASM_ARGS_1, "r" (_a2)
 336
 337 # define LOAD_ARGS_3(a1, a2, a3)                        \
 338   long int __arg3 = (long int) (a3);                    \
 339   LOAD_ARGS_2 (a1, a2)
 340 # define LOAD_REGS_3                                    \
 341   register long int _a3 asm ("rdx") = __arg3;           \
 342   LOAD_REGS_2
 343 # define ASM_ARGS_3     ASM_ARGS_2, "r" (_a3)
 344
 345 # define LOAD_ARGS_4(a1, a2, a3, a4)                    \
 346   long int __arg4 = (long int) (a4);                    \
 347   LOAD_ARGS_3 (a1, a2, a3)
 348 # define LOAD_REGS_4                                    \
 349   register long int _a4 asm ("r10") = __arg4;           \
 350   LOAD_REGS_3
 351 # define ASM_ARGS_4     ASM_ARGS_3, "r" (_a4)
 352
 353 # define LOAD_ARGS_5(a1, a2, a3, a4, a5)                \
 354   long int __arg5 = (long int) (a5);                    \
 355   LOAD_ARGS_4 (a1, a2, a3, a4)
 356 # define LOAD_REGS_5                                    \
 357   register long int _a5 asm ("r8") = __arg5;            \
 358   LOAD_REGS_4
 359 # define ASM_ARGS_5     ASM_ARGS_4, "r" (_a5)
 360
 361 # define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6)            \
 362   long int __arg6 = (long int) (a6);                    \
 363   LOAD_ARGS_5 (a1, a2, a3, a4, a5)
 364 # define LOAD_REGS_6                                    \
 365   register long int _a6 asm ("r9") = __arg6;            \
 366   LOAD_REGS_5
 367 # define ASM_ARGS_6     ASM_ARGS_5, "r" (_a6)
 368
 369 #endif  /* __ASSEMBLER__ */
 370
 371
 372 /* Pointer mangling support.  */
 373 #if defined NOT_IN_libc && defined IS_IN_rtld
 374 /* We cannot use the thread descriptor because in ld.so we use setjmp
 375    earlier than the descriptor is initialized.  */
 376 # ifdef __ASSEMBLER__
 377 #  define PTR_MANGLE(reg)       xorq __pointer_chk_guard_local(%rip), reg;    \
 378                                 rolq $17, reg
 379 #  define PTR_DEMANGLE(reg)     rorq $17, reg;                                \
 380                                 xorq __pointer_chk_guard_local(%rip), reg
 381 # else
 382 #  define PTR_MANGLE(reg)       asm ("xorq __pointer_chk_guard_local(%%rip), %0\n" \
 383                                      "rolq $17, %0"                           \
 384                                      : "=r" (reg) : "0" (reg))
 385 #  define PTR_DEMANGLE(reg)     asm ("rorq $17, %0\n"                         \
 386                                      "xorq __pointer_chk_guard_local(%%rip), %0" \
 387                                      : "=r" (reg) : "0" (reg))
 388 # endif
 389 #else
 390 # ifdef __ASSEMBLER__
 391 #  define PTR_MANGLE(reg)       xorq %fs:POINTER_GUARD, reg;                  \
 392                                 rolq $17, reg
 393 #  define PTR_DEMANGLE(reg)     rorq $17, reg;                                \
 394                                 xorq %fs:POINTER_GUARD, reg
 395 # else
 396 #  define PTR_MANGLE(var)       asm ("xorq %%fs:%c2, %0\n"                    \
 397                                      "rolq $17, %0"                           \
 398                                      : "=r" (var)                             \
 399                                      : "0" (var),                             \
 400                                        "i" (offsetof (tcbhead_t,              \
 401                                                       pointer_guard)))
 402 #  define PTR_DEMANGLE(var)     asm ("rorq $17, %0\n"                         \
 403                                      "xorq %%fs:%c2, %0"                      \
 404                                      : "=r" (var)                             \
 405                                      : "0" (var),                             \
 406                                        "i" (offsetof (tcbhead_t,              \
 407                                                       pointer_guard)))
 408 # endif
 409 #endif
 410
 411 #endif /* linux/x86_64/sysdep.h */