libc/sysdeps/linux/hppa/sysdep.h

   1 /* Assembler macros for PA-RISC.
   2    Copyright (C) 1999-2018 Free Software Foundation, Inc.
   3    Contributed by Ulrich Drepper, <drepper@cygnus.com>, August 1999.
   4    Linux/PA-RISC changes by Philipp Rumpf, <prumpf@tux.org>, March 2000.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library.  If not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef _LINUX_HPPA_SYSDEP_H
  21 #define _LINUX_HPPA_SYSDEP_H 1
  22
  23 #include <common/sysdep.h>
  24 #include <sys/syscall.h>
  25
  26 /* In order to get __set_errno() definition in INLINE_SYSCALL.  */
  27 #ifndef __ASSEMBLER__
  28 #include <errno.h>
  29 #endif
  30
  31 #undef ASM_LINE_SEP
  32 #define ASM_LINE_SEP !
  33
  34 #undef SYS_ify
  35 #define SYS_ify(syscall_name)   (__NR_##syscall_name)
  36
  37 /* The vfork, fork, and clone syscalls clobber r19
  38  * and r21. We list r21 as either clobbered or as an
  39  * input to a 6-argument syscall. We must save and
  40  * restore r19 in both PIC and non-PIC cases.
  41  */
  42 /* WARNING: TREG must be a callee saves register so
  43    that it doesn't have to be restored after a call
  44    to another function */
  45 #define TREG 4
  46 #define SAVE_PIC(SREG) \
  47         copy %r19, SREG
  48 #define LOAD_PIC(LREG) \
  49         copy LREG , %r19
  50 /* Inline assembly defines */
  51 #define TREG_ASM "%r4" /* Cant clobber r3, it holds framemarker */
  52 #define SAVE_ASM_PIC    "       copy %%r19, %" TREG_ASM "\n"
  53 #define LOAD_ASM_PIC    "       copy %" TREG_ASM ", %%r19\n"
  54 #define CLOB_TREG       TREG_ASM ,
  55 #define PIC_REG_DEF     register unsigned long __r19 asm("r19");
  56 #define PIC_REG_USE     , "r" (__r19)
  57
  58 #ifdef __ASSEMBLER__
  59
  60 /* Syntactic details of assembler.  */
  61
  62 #define ALIGNARG(log2) log2
  63
  64 /* For Linux we can use the system call table in the header file
  65         /usr/include/asm/unistd.h
  66    of the kernel.  But these symbols do not follow the SYS_* syntax
  67    so we have to redefine the `SYS_ify' macro here.  */
  68 #undef SYS_ify
  69 #define SYS_ify(syscall_name)   __NR_##syscall_name
  70
  71 /* ELF-like local names start with `.L'.  */
  72 #undef L
  73 #define L(name) .L##name
  74
  75 /* Linux uses a negative return value to indicate syscall errors,
  76    unlike most Unices, which use the condition codes' carry flag.
  77
  78    Since version 2.1 the return value of a system call might be
  79    negative even if the call succeeded.  E.g., the `lseek' system call
  80    might return a large offset.  Therefore we must not anymore test
  81    for < 0, but test for a real error by making sure the value in %eax
  82    is a real error number.  Linus said he will make sure the no syscall
  83    returns a value in -1 .. -4095 as a valid result so we can safely
  84    test with -4095.  */
  85
  86 /* We don't want the label for the error handle to be global when we define
  87    it here.  */
  88 /*#ifdef PIC
  89 # define SYSCALL_ERROR_LABEL 0f
  90 #else
  91 # define SYSCALL_ERROR_LABEL syscall_error
  92 #endif*/
  93
  94 /* Argument manipulation from the stack for preparing to
  95    make a syscall */
  96
  97 #define DOARGS_0 /* nothing */
  98 #define DOARGS_1 /* nothing */
  99 #define DOARGS_2 /* nothing */
 100 #define DOARGS_3 /* nothing */
 101 #define DOARGS_4 /* nothing */
 102 #define DOARGS_5 ldw -52(%sp), %r22             ASM_LINE_SEP
 103 #define DOARGS_6 DOARGS_5 ldw -56(%sp), %r21    ASM_LINE_SEP
 104
 105 #define UNDOARGS_0 /* nothing */
 106 #define UNDOARGS_1 /* nothing */
 107 #define UNDOARGS_2 /* nothing */
 108 #define UNDOARGS_3 /* nothing */
 109 #define UNDOARGS_4 /* nothing */
 110 #define UNDOARGS_5 /* nothing */
 111 #define UNDOARGS_6 /* nothing */
 112
 113 /* Define an entry point visible from C.
 114
 115    There is currently a bug in gdb which prevents us from specifying
 116    incomplete stabs information.  Fake some entries here which specify
 117    the current source file.  */
 118 #undef ENTRY
 119 #define ENTRY(name)                                                     \
 120         .text                                           ASM_LINE_SEP    \
 121         .align ALIGNARG(4)                              ASM_LINE_SEP    \
 122         .export C_SYMBOL_NAME(name)                     ASM_LINE_SEP    \
 123         .type   C_SYMBOL_NAME(name),@function           ASM_LINE_SEP    \
 124         cfi_startproc                                   ASM_LINE_SEP    \
 125         C_LABEL(name)                                   ASM_LINE_SEP    \
 126         .PROC                                           ASM_LINE_SEP    \
 127         .CALLINFO FRAME=64,CALLS,SAVE_RP,ENTRY_GR=3     ASM_LINE_SEP    \
 128         .ENTRY                                          ASM_LINE_SEP    \
 129         /* SAVE_RP says we do */                        ASM_LINE_SEP    \
 130         stw %rp, -20(%sr0,%sp)                          ASM_LINE_SEP    \
 131         .cfi_offset 2, -20                              ASM_LINE_SEP    \
 132         /*FIXME: Call mcount? (carefull with stack!) */
 133
 134 /* Some syscall wrappers do not call other functions, and
 135    hence are classified as leaf, so add NO_CALLS for gdb */
 136 #define ENTRY_LEAF(name)                                                \
 137         .text                                           ASM_LINE_SEP    \
 138         .align ALIGNARG(4)                              ASM_LINE_SEP    \
 139         .export C_SYMBOL_NAME(name)                     ASM_LINE_SEP    \
 140         .type   C_SYMBOL_NAME(name),@function           ASM_LINE_SEP    \
 141         cfi_startproc                                   ASM_LINE_SEP    \
 142         C_LABEL(name)                                   ASM_LINE_SEP    \
 143         .PROC                                           ASM_LINE_SEP    \
 144         .CALLINFO FRAME=64,NO_CALLS,SAVE_RP,ENTRY_GR=3  ASM_LINE_SEP    \
 145         .ENTRY                                          ASM_LINE_SEP    \
 146         /* SAVE_RP says we do */                        ASM_LINE_SEP    \
 147         stw %rp, -20(%sr0,%sp)                          ASM_LINE_SEP    \
 148         .cfi_offset 2, -20                              ASM_LINE_SEP    \
 149         /*FIXME: Call mcount? (carefull with stack!) */
 150
 151 #undef  END
 152 #define END(name)                                                       \
 153         .EXIT                                           ASM_LINE_SEP    \
 154         .PROCEND                                        ASM_LINE_SEP    \
 155         cfi_endproc                                     ASM_LINE_SEP    \
 156 .size   C_SYMBOL_NAME(name), .-C_SYMBOL_NAME(name)      ASM_LINE_SEP
 157
 158 /* If compiled for profiling, call `mcount' at the start
 159    of each function. No, don't bother.  gcc will put the
 160    call in for us.  */
 161 #define CALL_MCOUNT             /* Do nothing.  */
 162
 163 /* syscall wrappers consist of
 164         #include <sysdep.h>
 165         PSEUDO(...)
 166         ret
 167         PSEUDO_END(...)
 168
 169    which means
 170         ENTRY(name)
 171         DO_CALL(...)
 172         bv,n 0(2)
 173 */
 174
 175 #undef PSEUDO
 176 #define PSEUDO(name, syscall_name, args)                        \
 177   ENTRY (name)                                  ASM_LINE_SEP    \
 178   /* If necc. load args from stack */           ASM_LINE_SEP    \
 179   DOARGS_##args                                 ASM_LINE_SEP    \
 180   DO_CALL (syscall_name, args)                  ASM_LINE_SEP    \
 181   UNDOARGS_##args                               ASM_LINE_SEP
 182
 183 #define ret \
 184   /* Return value set by ERRNO code */          ASM_LINE_SEP    \
 185   bv,n 0(2)                                     ASM_LINE_SEP
 186
 187 #undef  PSEUDO_END
 188 #define PSEUDO_END(name)                                        \
 189   END (name)
 190
 191 /* We don't set the errno on the return from the syscall */
 192 #define PSEUDO_NOERRNO(name, syscall_name, args)                \
 193   ENTRY_LEAF (name)                             ASM_LINE_SEP    \
 194   DOARGS_##args                                 ASM_LINE_SEP    \
 195   DO_CALL_NOERRNO (syscall_name, args)          ASM_LINE_SEP    \
 196   UNDOARGS_##args                               ASM_LINE_SEP
 197
 198 #define ret_NOERRNO ret
 199
 200 #undef  PSEUDO_END_NOERRNO
 201 #define PSEUDO_END_NOERRNO(name)                                \
 202   END (name)
 203
 204 /* This has to return the error value */
 205 #undef  PSEUDO_ERRVAL
 206 #define PSEUDO_ERRVAL(name, syscall_name, args)                 \
 207   ENTRY_LEAF (name)                             ASM_LINE_SEP    \
 208   DOARGS_##args                                 ASM_LINE_SEP    \
 209   DO_CALL_ERRVAL (syscall_name, args)           ASM_LINE_SEP    \
 210   UNDOARGS_##args                               ASM_LINE_SEP
 211
 212 #define ret_ERRVAL ret
 213
 214 #undef  PSEUDO_END_ERRVAL
 215 #define PSEUDO_END_ERRVAL(name)                                 \
 216         END(name)
 217
 218 #undef JUMPTARGET
 219 #define JUMPTARGET(name)        name
 220 #define SYSCALL_PIC_SETUP       /* Nothing.  */
 221
 222
 223 /* FIXME: This comment is not true.
 224  * All the syscall assembly macros rely on finding the appropriate
 225    SYSCALL_ERROR_LABEL or rather HANDLER. */
 226
 227 /* int * __errno_location(void) so you have to store your value
 228    into the return address! */
 229 #define DEFAULT_SYSCALL_ERROR_HANDLER                   \
 230         .import __errno_location,code   ASM_LINE_SEP    \
 231         /* branch to errno handler */   ASM_LINE_SEP    \
 232         bl __errno_location,%rp         ASM_LINE_SEP
 233
 234 /* Here are the myriad of configuration options that the above can
 235    work for... what we've done is provide the framework for future
 236    changes if required to each section */
 237
 238 #ifdef __PIC__
 239 #  if defined _LIBC_REENTRANT
 240 #   define SYSCALL_ERROR_HANDLER DEFAULT_SYSCALL_ERROR_HANDLER
 241 #  else /* !_LIBC_REENTRANT */
 242 #   define SYSCALL_ERROR_HANDLER DEFAULT_SYSCALL_ERROR_HANDLER
 243 #  endif /* _LIBC_REENTRANT */
 244 #else
 245 # ifndef _LIBC_REENTRANT
 246 #  define SYSCALL_ERROR_HANDLER DEFAULT_SYSCALL_ERROR_HANDLER
 247 # else
 248 #  define SYSCALL_ERROR_HANDLER DEFAULT_SYSCALL_ERROR_HANDLER
 249 # endif
 250 #endif
 251
 252
 253 /* Linux takes system call arguments in registers:
 254         syscall number  gr20
 255         arg 1           gr26
 256         arg 2           gr25
 257         arg 3           gr24
 258         arg 4           gr23
 259         arg 5           gr22
 260         arg 6           gr21
 261
 262    The compiler calls us by the C convention:
 263         syscall number  in the DO_CALL macro
 264         arg 1           gr26
 265         arg 2           gr25
 266         arg 3           gr24
 267         arg 4           gr23
 268         arg 5           -52(sp)
 269         arg 6           -56(sp)
 270
 271    gr22 and gr21 are caller-saves, so we can just load the arguments
 272    there and generally be happy. */
 273
 274 /* the cmpb...no_error code below inside DO_CALL
 275  * is intended to mimic the if (__sys_res...)
 276  * code inside INLINE_SYSCALL
 277  */
 278 #define NO_ERROR -0x1000
 279
 280 #undef  DO_CALL
 281 #define DO_CALL(syscall_name, args)                             \
 282         /* Create a frame */                    ASM_LINE_SEP    \
 283         stwm TREG, 64(%sp)                      ASM_LINE_SEP    \
 284         .cfi_def_cfa_offset -64                 ASM_LINE_SEP    \
 285         .cfi_offset TREG, 0                     ASM_LINE_SEP    \
 286         stw %sp, -4(%sp)                        ASM_LINE_SEP    \
 287         stw %r19, -32(%sp)                      ASM_LINE_SEP    \
 288         .cfi_offset 19, 32                      ASM_LINE_SEP    \
 289         /* Save r19 */                          ASM_LINE_SEP    \
 290         SAVE_PIC(TREG)                          ASM_LINE_SEP    \
 291         /* Do syscall, delay loads # */         ASM_LINE_SEP    \
 292         ble  0x100(%sr2,%r0)                    ASM_LINE_SEP    \
 293         ldi SYS_ify (syscall_name), %r20        ASM_LINE_SEP    \
 294         ldi NO_ERROR,%r1                        ASM_LINE_SEP    \
 295         cmpb,>>=,n %r1,%ret0,L(pre_end)         ASM_LINE_SEP    \
 296         /* Restore r19 from TREG */             ASM_LINE_SEP    \
 297         LOAD_PIC(TREG) /* delay */              ASM_LINE_SEP    \
 298         SYSCALL_ERROR_HANDLER                   ASM_LINE_SEP    \
 299         /* Use TREG for temp storage */         ASM_LINE_SEP    \
 300         copy %ret0, TREG /* delay */            ASM_LINE_SEP    \
 301         /* OPTIMIZE: Don't reload r19 */        ASM_LINE_SEP    \
 302         /* do a -1*syscall_ret0 */              ASM_LINE_SEP    \
 303         sub %r0, TREG, TREG                     ASM_LINE_SEP    \
 304         /* Store into errno location */         ASM_LINE_SEP    \
 305         stw TREG, 0(%sr0,%ret0)                 ASM_LINE_SEP    \
 306         /* return -1 as error */                ASM_LINE_SEP    \
 307         ldo -1(%r0), %ret0                      ASM_LINE_SEP    \
 308 L(pre_end):                                     ASM_LINE_SEP    \
 309         /* Restore our frame, restoring TREG */ ASM_LINE_SEP    \
 310         ldwm -64(%sp), TREG                     ASM_LINE_SEP    \
 311         /* Restore return pointer */            ASM_LINE_SEP    \
 312         ldw -20(%sp),%rp                        ASM_LINE_SEP
 313
 314 /* We do nothing with the return, except hand it back to someone else */
 315 #undef  DO_CALL_NOERRNO
 316 #define DO_CALL_NOERRNO(syscall_name, args)                     \
 317         /* No need to store r19 */              ASM_LINE_SEP    \
 318         ble  0x100(%sr2,%r0)                    ASM_LINE_SEP    \
 319         ldi SYS_ify (syscall_name), %r20        ASM_LINE_SEP    \
 320         /* Caller will restore r19 */           ASM_LINE_SEP
 321
 322 /* Here, we return the ERRVAL in assembly, note we don't call the
 323    error handler function, but we do 'negate' the return _IF_
 324    it's an error. Not sure if this is the right semantic. */
 325
 326 #undef  DO_CALL_ERRVAL
 327 #define DO_CALL_ERRVAL(syscall_name, args)                      \
 328         /* No need to store r19 */              ASM_LINE_SEP    \
 329         ble  0x100(%sr2,%r0)                    ASM_LINE_SEP    \
 330         ldi SYS_ify (syscall_name), %r20        ASM_LINE_SEP    \
 331         /* Caller will restore r19 */           ASM_LINE_SEP    \
 332         ldi NO_ERROR,%r1                        ASM_LINE_SEP    \
 333         cmpb,>>=,n %r1,%ret0,0f                 ASM_LINE_SEP    \
 334         sub %r0, %ret0, %ret0                   ASM_LINE_SEP    \
 335 0:                                              ASM_LINE_SEP
 336
 337
 338 #else
 339
 340 /* GCC has to be warned that a syscall may clobber all the ABI
 341    registers listed as "caller-saves", see page 8, Table 2
 342    in section 2.2.6 of the PA-RISC RUN-TIME architecture
 343    document. However! r28 is the result and will conflict with
 344    the clobber list so it is left out. Also the input arguments
 345    registers r20 -> r26 will conflict with the list so they
 346    are treated specially. Although r19 is clobbered by the syscall
 347    we cannot say this because it would violate ABI, thus we say
 348    TREG is clobbered and use that register to save/restore r19
 349    across the syscall. */
 350
 351 #define CALL_CLOB_REGS  "%r1", "%r2", CLOB_TREG \
 352                         "%r20", "%r29", "%r31"
 353
 354 #endif  /* __ASSEMBLER__ */
 355
 356 #endif /* _LINUX_HPPA_SYSDEP_H */