gdbserver/linux-or1k-low.cc

   1 /* GNU/Linux/OR1K specific low level interface for the GDB server.
   2    Copyright (C) 2021-2023 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program 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
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include "server.h"
  20 #include "linux-low.h"
  21 #include "elf/common.h"
  22 #include "nat/gdb_ptrace.h"
  23 #include <endian.h>
  24 #include "gdb_proc_service.h"
  25 #include <asm/ptrace.h>
  26
  27 #ifndef PTRACE_GET_THREAD_AREA
  28 #define PTRACE_GET_THREAD_AREA 25
  29 #endif
  30
  31 /* Linux target op definitions for the OpenRISC architecture.  */
  32
  33 class or1k_target : public linux_process_target
  34 {
  35 public:
  36
  37   const regs_info *get_regs_info () override;
  38
  39   const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override;
  40
  41 protected:
  42
  43   void low_arch_setup () override;
  44
  45   bool low_cannot_fetch_register (int regno) override;
  46
  47   bool low_cannot_store_register (int regno) override;
  48
  49   bool low_supports_breakpoints () override;
  50
  51   CORE_ADDR low_get_pc (regcache *regcache) override;
  52
  53   void low_set_pc (regcache *regcache, CORE_ADDR newpc) override;
  54
  55   bool low_breakpoint_at (CORE_ADDR pc) override;
  56 };
  57
  58 /* The singleton target ops object.  */
  59
  60 static or1k_target the_or1k_target;
  61
  62 bool
  63 or1k_target::low_supports_breakpoints ()
  64 {
  65   return true;
  66 }
  67
  68 CORE_ADDR
  69 or1k_target::low_get_pc (regcache *regcache)
  70 {
  71   return linux_get_pc_32bit (regcache);
  72 }
  73
  74 void
  75 or1k_target::low_set_pc (regcache *regcache, CORE_ADDR pc)
  76 {
  77   linux_set_pc_32bit (regcache, pc);
  78 }
  79
  80 /* The following definition must agree with the number of registers
  81    defined in "struct user_regs" in GLIBC
  82    (sysdeps/unix/sysv/linux/or1k/sys/ucontext.h), and also with
  83    OR1K_NUM_REGS in GDB proper.  */
  84
  85 #define or1k_num_regs 35
  86
  87 /* Defined in auto-generated file or1k-linux.c.  */
  88
  89 void init_registers_or1k_linux (void);
  90 extern const struct target_desc *tdesc_or1k_linux;
  91
  92 /* This union is used to convert between int and byte buffer
  93    representations of register contents.  */
  94
  95 union or1k_register
  96 {
  97   unsigned char buf[4];
  98   int reg32;
  99 };
 100
 101 /* Return the ptrace ``address'' of register REGNO. */
 102
 103 static int or1k_regmap[] = {
 104   -1,  1,  2,  3,  4,  5,  6,  7,
 105   8,  9,  10, 11, 12, 13, 14, 15,
 106   16, 17, 18, 19, 20, 21, 22, 23,
 107   24, 25, 26, 27, 28, 29, 30, 31,
 108   -1, /* PC */
 109   -1, /* ORIGINAL R11 */
 110   -1  /* SYSCALL NO */
 111 };
 112
 113 /* Implement the low_arch_setup linux target ops method.  */
 114
 115 void
 116 or1k_target::low_arch_setup ()
 117 {
 118   current_process ()->tdesc = tdesc_or1k_linux;
 119 }
 120
 121 /* Implement the low_cannot_fetch_register linux target ops method.  */
 122
 123 bool
 124 or1k_target::low_cannot_fetch_register (int regno)
 125 {
 126   return (or1k_regmap[regno] == -1);
 127 }
 128
 129 /* Implement the low_cannot_store_register linux target ops method.  */
 130
 131 bool
 132 or1k_target::low_cannot_store_register (int regno)
 133 {
 134   return (or1k_regmap[regno] == -1);
 135 }
 136
 137 /* Breakpoint support.  */
 138
 139 static const unsigned int or1k_breakpoint = 0x21000001;
 140 #define or1k_breakpoint_len 4
 141
 142 /* Implementation of target ops method "sw_breakpoint_from_kind".  */
 143
 144 const gdb_byte *
 145 or1k_target::sw_breakpoint_from_kind (int kind, int *size)
 146 {
 147   *size = or1k_breakpoint_len;
 148   return (const gdb_byte *) &or1k_breakpoint;
 149 }
 150
 151 /* Implement the low_breakpoint_at linux target ops method.  */
 152
 153 bool
 154 or1k_target::low_breakpoint_at (CORE_ADDR where)
 155 {
 156   unsigned int insn;
 157
 158   read_memory (where, (unsigned char *) &insn, or1k_breakpoint_len);
 159   if (insn == or1k_breakpoint)
 160     return true;
 161   return false;
 162 }
 163
 164 /* Fetch the thread-local storage pointer for libthread_db.  */
 165
 166 ps_err_e
 167 ps_get_thread_area (struct ps_prochandle *ph,
 168                     lwpid_t lwpid, int idx, void **base)
 169 {
 170   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 171     return PS_ERR;
 172
 173   /* IDX is the bias from the thread pointer to the beginning of the
 174      thread descriptor.  It has to be subtracted due to implementation
 175      quirks in libthread_db.  */
 176   *base = (void *) ((char *) *base - idx);
 177
 178   return PS_OK;
 179 }
 180
 181 /* Helper functions to collect/supply a single register REGNO.  */
 182
 183 static void
 184 or1k_collect_register (struct regcache *regcache, int regno,
 185                         union or1k_register *reg)
 186 {
 187   union or1k_register tmp_reg;
 188
 189   collect_register (regcache, regno, &tmp_reg.reg32);
 190   reg->reg32 = tmp_reg.reg32;
 191 }
 192
 193 static void
 194 or1k_supply_register (struct regcache *regcache, int regno,
 195                        const union or1k_register *reg)
 196 {
 197   supply_register (regcache, regno, reg->buf);
 198 }
 199
 200 /* We have only a single register set on OpenRISC.  */
 201
 202 static void
 203 or1k_fill_gregset (struct regcache *regcache, void *buf)
 204 {
 205   union or1k_register *regset = (union or1k_register *) buf;
 206   int i;
 207
 208   for (i = 1; i < or1k_num_regs; i++)
 209     or1k_collect_register (regcache, i, regset + i);
 210 }
 211
 212 static void
 213 or1k_store_gregset (struct regcache *regcache, const void *buf)
 214 {
 215   const union or1k_register *regset = (union or1k_register *) buf;
 216   int i;
 217
 218   for (i = 0; i < or1k_num_regs; i++)
 219     or1k_supply_register (regcache, i, regset + i);
 220 }
 221
 222 static struct regset_info or1k_regsets[] =
 223 {
 224   { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS,
 225     or1k_num_regs * 4, GENERAL_REGS,
 226     or1k_fill_gregset, or1k_store_gregset },
 227   NULL_REGSET
 228 };
 229
 230 static struct regsets_info or1k_regsets_info =
 231   {
 232     or1k_regsets, /* regsets */
 233     0, /* num_regsets */
 234     NULL, /* disabled_regsets */
 235   };
 236
 237 static struct usrregs_info or1k_usrregs_info =
 238   {
 239     or1k_num_regs,
 240     or1k_regmap,
 241   };
 242
 243 static struct regs_info or1k_regs =
 244   {
 245     NULL, /* regset_bitmap */
 246     &or1k_usrregs_info,
 247     &or1k_regsets_info
 248   };
 249
 250 const regs_info *
 251 or1k_target::get_regs_info ()
 252 {
 253   return &or1k_regs;
 254 }
 255
 256 /* The linux target ops object.  */
 257
 258 linux_process_target *the_linux_target = &the_or1k_target;
 259
 260 void
 261 initialize_low_arch (void)
 262 {
 263   init_registers_or1k_linux ();
 264
 265   initialize_regsets_info (&or1k_regsets_info);
 266 }