sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h

   1 /* Copyright (C) 2000-2020 Free Software Foundation, Inc.
   2    Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
   3    This file is part of the GNU C Library.
   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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _LINUX_S390_SYSDEP_H
  20 #define _LINUX_S390_SYSDEP_H
  21
  22 #include <sysdeps/s390/s390-32/sysdep.h>
  23 #include <sysdeps/unix/sysdep.h>
  24 #include <sysdeps/unix/sysv/linux/s390/sysdep.h>
  25 #include <sysdeps/unix/sysv/linux/sysdep.h>
  26 #include <dl-sysdep.h>  /* For RTLD_PRIVATE_ERRNO.  */
  27 #include <tls.h>
  28
  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 /* in newer 2.1 kernels __NR_syscall is missing so we define it here */
  34 #define __NR_syscall 0
  35
  36 #ifdef __ASSEMBLER__
  37
  38 /* Linux uses a negative return value to indicate syscall errors, unlike
  39    most Unices, which use the condition codes' carry flag.
  40
  41    Since version 2.1 the return value of a system call might be negative
  42    even if the call succeeded.  E.g., the `lseek' system call might return
  43    a large offset.  Therefore we must not anymore test for < 0, but test
  44    for a real error by making sure the value in gpr2 is a real error
  45    number.  Linus said he will make sure that no syscall returns a value
  46    in -1 .. -4095 as a valid result so we can savely test with -4095.  */
  47
  48 #undef PSEUDO
  49 #define PSEUDO(name, syscall_name, args)                                      \
  50   .text;                                                                      \
  51   ENTRY (name)                                                                \
  52     DO_CALL (syscall_name, args);                                             \
  53     lhi  %r4,-4095 ;                                                          \
  54     clr  %r2,%r4 ;                                                            \
  55     jnl  SYSCALL_ERROR_LABEL
  56
  57 #undef PSEUDO_END
  58 #define PSEUDO_END(name)                                                      \
  59   SYSCALL_ERROR_HANDLER;                                                      \
  60   END (name)
  61
  62 #undef PSEUDO_NOERRNO
  63 #define PSEUDO_NOERRNO(name, syscall_name, args)                              \
  64   .text;                                                                      \
  65   ENTRY (name)                                                                \
  66     DO_CALL (syscall_name, args)
  67
  68 #undef PSEUDO_END_NOERRNO
  69 #define PSEUDO_END_NOERRNO(name)                                              \
  70   END (name)
  71
  72 #undef PSEUDO_ERRVAL
  73 #define PSEUDO_ERRVAL(name, syscall_name, args)                               \
  74   .text;                                                                      \
  75   ENTRY (name)                                                                \
  76     DO_CALL (syscall_name, args);                                             \
  77     lcr %r2,%r2
  78
  79 #undef PSEUDO_END_ERRVAL
  80 #define PSEUDO_END_ERRVAL(name)                                               \
  81   END (name)
  82
  83 #undef SYSCALL_ERROR_LABEL
  84 #ifndef PIC
  85 # undef SYSCALL_ERROR_LABEL
  86 # define SYSCALL_ERROR_LABEL 0f
  87 # define SYSCALL_ERROR_HANDLER \
  88 0:  basr  %r1,0;                                                              \
  89 1:  l     %r1,2f-1b(%r1);                                                     \
  90     br    %r1;                                                                \
  91 2:  .long syscall_error
  92 #else
  93 # if RTLD_PRIVATE_ERRNO
  94 #  undef SYSCALL_ERROR_LABEL
  95 #  define SYSCALL_ERROR_LABEL 0f
  96 #  define SYSCALL_ERROR_HANDLER \
  97 0:  basr  %r1,0;                                                              \
  98 1:  al    %r1,2f-1b(%r1);                                                     \
  99     lcr   %r2,%r2;                                                            \
 100     st    %r2,0(%r1);                                                         \
 101     lhi   %r2,-1;                                                             \
 102     br    %r14;                                                               \
 103 2:  .long rtld_errno-1b
 104 # elif defined _LIBC_REENTRANT
 105 #  if IS_IN (libc)
 106 #   define SYSCALL_ERROR_ERRNO __libc_errno
 107 #  else
 108 #   define SYSCALL_ERROR_ERRNO errno
 109 #  endif
 110 #  undef SYSCALL_ERROR_LABEL
 111 #  define SYSCALL_ERROR_LABEL 0f
 112 #  define SYSCALL_ERROR_HANDLER \
 113 0:  lcr   %r0,%r2;                                                            \
 114     basr  %r1,0;                                                              \
 115 1:  al    %r1,2f-1b(%r1);                                                     \
 116     l     %r1,SYSCALL_ERROR_ERRNO@gotntpoff(%r1);                             \
 117     ear   %r2,%a0;                                                            \
 118     st    %r0,0(%r1,%r2);                                                     \
 119     lhi   %r2,-1;                                                             \
 120     br    %r14;                                                               \
 121 2:  .long _GLOBAL_OFFSET_TABLE_-1b
 122 # else
 123 #  undef SYSCALL_ERROR_LABEL
 124 #  define SYSCALL_ERROR_LABEL 0f
 125 #  define SYSCALL_ERROR_HANDLER \
 126 0:  basr  %r1,0;                                                              \
 127 1:  al    %r1,2f-1b(%r1);                                                     \
 128     l     %r1,errno@GOT(%r1);                                                 \
 129     lcr   %r2,%r2;                                                            \
 130     st    %r2,0(%r1);                                                         \
 131     lhi   %r2,-1;                                                             \
 132     br    %r14;                                                               \
 133 2:  .long _GLOBAL_OFFSET_TABLE_-1b
 134 # endif /* _LIBC_REENTRANT */
 135 #endif /* PIC */
 136
 137 /* Linux takes system call arguments in registers:
 138
 139         syscall number  1            call-clobbered
 140         arg 1           2            call-clobbered
 141         arg 2           3            call-clobbered
 142         arg 3           4            call-clobbered
 143         arg 4           5            call-clobbered
 144         arg 5           6            call-saved
 145         arg 6           7            call-saved
 146
 147    (Of course a function with say 3 arguments does not have entries for
 148    arguments 4 and 5.)
 149    For system calls with 6 parameters a stack operation is required
 150    to load the 6th parameter to register 7. Call saved register 7 is
 151    moved to register 0 and back to avoid an additional stack frame.
 152  */
 153
 154 #define DO_CALL(syscall, args)                                                \
 155   .if args > 5;                                                               \
 156     lr %r0,%r7;                                                               \
 157     l %r7,96(%r15);                                                           \
 158   .endif;                                                                     \
 159   .if SYS_ify (syscall) < 256;                                                \
 160     svc SYS_ify (syscall);                                                    \
 161   .else;                                                                      \
 162     lhi %r1,SYS_ify (syscall);                                                \
 163     svc 0;                                                                    \
 164   .endif;                                                                     \
 165   .if args > 5;                                                               \
 166     lr %r7,%r0;                                                               \
 167   .endif
 168
 169 #define ret                                                                   \
 170     br      14
 171
 172 #define ret_NOERRNO                                                           \
 173     br      14
 174
 175 #define ret_ERRVAL                                                            \
 176     br      14
 177
 178 #else
 179
 180 # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL
 181 # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1
 182
 183 #endif /* __ASSEMBLER__ */
 184
 185 /* Pointer mangling support.  */
 186 #if IS_IN (rtld)
 187 /* We cannot use the thread descriptor because in ld.so we use setjmp
 188    earlier than the descriptor is initialized.  */
 189 #else
 190 /* For the time being just use stack_guard rather than a separate
 191    pointer_guard.  */
 192 # ifdef __ASSEMBLER__
 193 #  define PTR_MANGLE(reg, tmpreg) \
 194   ear     tmpreg,%a0;                   \
 195   x       reg,STACK_GUARD(tmpreg)
 196 #  define PTR_MANGLE2(reg, tmpreg) \
 197   x       reg,STACK_GUARD(tmpreg)
 198 #  define PTR_DEMANGLE(reg, tmpreg) PTR_MANGLE (reg, tmpreg)
 199 # else
 200 #  define PTR_MANGLE(var) \
 201   (var) = (void *) ((uintptr_t) (var) ^ THREAD_GET_POINTER_GUARD ())
 202 #  define PTR_DEMANGLE(var)     PTR_MANGLE (var)
 203 # endif
 204 #endif
 205
 206 #endif /* _LINUX_S390_SYSDEP_H */