libc/sysdeps/linux/sparc64/sysdep.h

   1 /* Copyright (C) 1997-2017 Free Software Foundation, Inc.
   2    Contributed by Richard Henderson <richard@gnu.ai.mit.edu>, 1997.
   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_SPARC64_SYSDEP_H
  19 #define _LINUX_SPARC64_SYSDEP_H 1
  20
  21 #include <common/sysdep.h>
  22
  23 #undef SYS_ify
  24 #define SYS_ify(syscall_name) __NR_##syscall_name
  25
  26 #ifdef __ASSEMBLER__
  27
  28 #define SPARC_PIC_THUNK(reg)                                            \
  29         .ifndef __sparc_get_pc_thunk.reg;                               \
  30         .section .text.__sparc_get_pc_thunk.reg,"axG",@progbits,__sparc_get_pc_thunk.reg,comdat; \
  31         .align   32;                                                    \
  32         .weak    __sparc_get_pc_thunk.reg;                              \
  33         .hidden  __sparc_get_pc_thunk.reg;                              \
  34         .type    __sparc_get_pc_thunk.reg, #function;                   \
  35 __sparc_get_pc_thunk.reg:                                               \
  36         jmp     %o7 + 8;                                                \
  37          add    %o7, %reg, %##reg;                                      \
  38         .previous;                                                      \
  39         .endif;
  40
  41 /* The "-4" and "+4" offsets against _GLOBAL_OFFSET_TABLE_ are
  42    critical since they represent the offset from the thunk call to the
  43    instruction containing the _GLOBAL_OFFSET_TABLE_ reference.
  44    Therefore these instructions cannot be moved around without
  45    appropriate adjustments to those offsets.
  46
  47    Furthermore, these expressions are special in another regard.  When
  48    the assembler sees a reference to _GLOBAL_OFFSET_TABLE_ inside of
  49    a %hi() or %lo(), it emits a PC-relative relocation.  This causes
  50    R_SPARC_HI22 to turn into R_SPARC_PC22, and R_SPARC_LO10 to turn into
  51    R_SPARC_PC10, respectively.
  52
  53    Even when v9 we use a call sequence instead of using "rd %pc" because
  54    RDPC is extremely expensive and incurs a full pipeline flush.  */
  55
  56 #define SPARC_PIC_THUNK_CALL(reg)                                       \
  57         sethi   %hi(_GLOBAL_OFFSET_TABLE_-4), %##reg;                   \
  58         call    __sparc_get_pc_thunk.reg;                               \
  59          or     %##reg, %lo(_GLOBAL_OFFSET_TABLE_+4), %##reg;
  60
  61 #define SETUP_PIC_REG(reg)                                              \
  62         SPARC_PIC_THUNK(reg)                                            \
  63         SPARC_PIC_THUNK_CALL(reg)
  64
  65 #define SETUP_PIC_REG_LEAF(reg, tmp)                                    \
  66         SPARC_PIC_THUNK(reg)                                            \
  67         mov     %o7, %##tmp;                                            \
  68         SPARC_PIC_THUNK_CALL(reg);                                      \
  69         mov     %##tmp, %o7;
  70
  71
  72 #define LOADSYSCALL(x) mov __NR_##x, %g1
  73
  74 #define ENTRY(name)                 \
  75     .align 4;                       \
  76     .global C_SYMBOL_NAME(name);    \
  77     .type   name, @function;        \
  78 C_LABEL(name)                       \
  79     cfi_startproc;
  80
  81 #undef END
  82 #define END(name)                   \
  83     cfi_endproc;                    \
  84     .size name, . - name
  85
  86 #define ENTRY_NOCFI(name)                       \
  87         .align  4;                      \
  88         .global C_SYMBOL_NAME(name);    \
  89         .type   name, @function;            \
  90 C_LABEL(name)
  91
  92 #define END_NOCFI(name)                     \
  93         .size name, . - name
  94
  95 #define LOC(name) .L##name
  96
  97 #undef PSEUDO
  98 #define PSEUDO(name, syscall_name, args)        \
  99         .text;                                  \
 100 ENTRY(name);                                    \
 101         LOADSYSCALL(syscall_name);              \
 102         ta              0x6d;                   \
 103         bcc,pt          %xcc, 1f;               \
 104          nop;                                   \
 105         SYSCALL_ERROR_HANDLER                   \
 106 1:
 107
 108 #undef PSEUDO_NOERRNO
 109 #define PSEUDO_NOERRNO(name, syscall_name, args)\
 110         .text;                                  \
 111 ENTRY(name);                                    \
 112         LOADSYSCALL(syscall_name);              \
 113         ta              0x6d;
 114
 115 #undef PSEUDO_ERRVAL
 116 #define PSEUDO_ERRVAL(name, syscall_name, args) \
 117         .text;                                  \
 118 ENTRY(name);                                    \
 119         LOADSYSCALL(syscall_name);              \
 120         ta              0x6d;
 121
 122 #undef PSEUDO_END
 123 #define PSEUDO_END(name)                        \
 124         END(name)
 125
 126 #ifndef __PIC__
 127 # define SYSCALL_ERROR_HANDLER                  \
 128         mov     %o7, %g1;                       \
 129         call    __syscall_error;                \
 130          mov    %g1, %o7;
 131 #else
 132 # define SYSCALL_ERROR_HANDLER          \
 133 0:      SETUP_PIC_REG_LEAF(o2,g1)       \
 134         sethi   %gdop_hix22(errno), %g1;\
 135         xor     %g1, %gdop_lox10(errno), %g1;\
 136         ldx     [%o2 + %g1], %g1, %gdop(errno);\
 137         st      %o0, [%g1];             \
 138         jmp     %o7 + 8;                \
 139          mov    -1, %o0;
 140 #endif  /* PIC */
 141
 142 #endif  /* __ASSEMBLER__ */
 143
 144 /* This is the offset from the %sp to the backing store above the
 145    register windows.  So if you poke stack memory directly you add this.  */
 146 #define STACK_BIAS      2047
 147
 148 #endif