gdbserver/linux-loongarch-low.cc

   1 /* GNU/Linux/LoongArch specific low level interface, for the remote server
   2    for GDB.
   3    Copyright (C) 2022-2023 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "server.h"
  21 #include "linux-low.h"
  22 #include "tdesc.h"
  23 #include "elf/common.h"
  24 #include "arch/loongarch.h"
  25
  26 /* Linux target ops definitions for the LoongArch architecture.  */
  27
  28 class loongarch_target : public linux_process_target
  29 {
  30 public:
  31
  32   const regs_info *get_regs_info () override;
  33
  34   int breakpoint_kind_from_pc (CORE_ADDR *pcptr) override;
  35
  36   const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override;
  37
  38 protected:
  39
  40   void low_arch_setup () override;
  41
  42   bool low_cannot_fetch_register (int regno) override;
  43
  44   bool low_cannot_store_register (int regno) override;
  45
  46   bool low_fetch_register (regcache *regcache, int regno) override;
  47
  48   bool low_supports_breakpoints () override;
  49
  50   CORE_ADDR low_get_pc (regcache *regcache) override;
  51
  52   void low_set_pc (regcache *regcache, CORE_ADDR newpc) override;
  53
  54   bool low_breakpoint_at (CORE_ADDR pc) override;
  55 };
  56
  57 /* The singleton target ops object.  */
  58
  59 static loongarch_target the_loongarch_target;
  60
  61 bool
  62 loongarch_target::low_cannot_fetch_register (int regno)
  63 {
  64   gdb_assert_not_reached ("linux target op low_cannot_fetch_register "
  65                           "is not implemented by the target");
  66 }
  67
  68 bool
  69 loongarch_target::low_cannot_store_register (int regno)
  70 {
  71   gdb_assert_not_reached ("linux target op low_cannot_store_register "
  72                           "is not implemented by the target");
  73 }
  74
  75 /* Implementation of linux target ops method "low_arch_setup".  */
  76
  77 void
  78 loongarch_target::low_arch_setup ()
  79 {
  80   static const char *expedite_regs[] = { "r3", "pc", NULL };
  81   loongarch_gdbarch_features features;
  82   target_desc_up tdesc;
  83
  84   features.xlen = sizeof (elf_greg_t);
  85   tdesc = loongarch_create_target_description (features);
  86
  87   if (tdesc->expedite_regs.empty ())
  88     {
  89       init_target_desc (tdesc.get (), expedite_regs);
  90       gdb_assert (!tdesc->expedite_regs.empty ());
  91     }
  92   current_process ()->tdesc = tdesc.release ();
  93 }
  94
  95 /* Collect GPRs from REGCACHE into BUF.  */
  96
  97 static void
  98 loongarch_fill_gregset (struct regcache *regcache, void *buf)
  99 {
 100   elf_gregset_t *regset = (elf_gregset_t *) buf;
 101   int i;
 102
 103   for (i = 1; i < 32; i++)
 104     collect_register (regcache, i, *regset + i);
 105   collect_register (regcache, LOONGARCH_ORIG_A0_REGNUM, *regset + LOONGARCH_ORIG_A0_REGNUM);
 106   collect_register (regcache, LOONGARCH_PC_REGNUM, *regset + LOONGARCH_PC_REGNUM);
 107   collect_register (regcache, LOONGARCH_BADV_REGNUM, *regset + LOONGARCH_BADV_REGNUM);
 108 }
 109
 110 /* Supply GPRs from BUF into REGCACHE.  */
 111
 112 static void
 113 loongarch_store_gregset (struct regcache *regcache, const void *buf)
 114 {
 115   const elf_gregset_t *regset = (const elf_gregset_t *) buf;
 116   int i;
 117
 118   supply_register_zeroed (regcache, 0);
 119   for (i = 1; i < 32; i++)
 120     supply_register (regcache, i, *regset + i);
 121   supply_register (regcache, LOONGARCH_ORIG_A0_REGNUM, *regset + LOONGARCH_ORIG_A0_REGNUM);
 122   supply_register (regcache, LOONGARCH_PC_REGNUM, *regset + LOONGARCH_PC_REGNUM);
 123   supply_register (regcache, LOONGARCH_BADV_REGNUM, *regset + LOONGARCH_BADV_REGNUM);
 124 }
 125
 126 /* Collect FPRs from REGCACHE into BUF.  */
 127
 128 static void
 129 loongarch_fill_fpregset (struct regcache *regcache, void *buf)
 130 {
 131   gdb_byte *regbuf = nullptr;
 132   int fprsize = register_size (regcache->tdesc, LOONGARCH_FIRST_FP_REGNUM);
 133   int fccsize = register_size (regcache->tdesc, LOONGARCH_FIRST_FCC_REGNUM);
 134
 135   for (int i = 0; i < LOONGARCH_LINUX_NUM_FPREGSET; i++)
 136     {
 137       regbuf = (gdb_byte *)buf + fprsize * i;
 138       collect_register (regcache, LOONGARCH_FIRST_FP_REGNUM + i, regbuf);
 139     }
 140
 141   for (int i = 0; i < LOONGARCH_LINUX_NUM_FCC; i++)
 142     {
 143       regbuf = (gdb_byte *)buf + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 144         fccsize * i;
 145       collect_register (regcache, LOONGARCH_FIRST_FCC_REGNUM + i, regbuf);
 146     }
 147
 148   regbuf = (gdb_byte *)buf + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 149     fccsize * LOONGARCH_LINUX_NUM_FCC;
 150   collect_register (regcache, LOONGARCH_FCSR_REGNUM, regbuf);
 151 }
 152
 153 /* Supply FPRs from BUF into REGCACHE.  */
 154
 155 static void
 156 loongarch_store_fpregset (struct regcache *regcache, const void *buf)
 157 {
 158   const gdb_byte *regbuf = nullptr;
 159   int fprsize = register_size (regcache->tdesc, LOONGARCH_FIRST_FP_REGNUM);
 160   int fccsize = register_size (regcache->tdesc, LOONGARCH_FIRST_FCC_REGNUM);
 161
 162   for (int i = 0; i < LOONGARCH_LINUX_NUM_FPREGSET; i++)
 163     {
 164       regbuf = (const gdb_byte *)buf + fprsize * i;
 165       supply_register (regcache, LOONGARCH_FIRST_FP_REGNUM + i, regbuf);
 166     }
 167
 168   for (int i = 0; i < LOONGARCH_LINUX_NUM_FCC; i++)
 169     {
 170       regbuf = (const gdb_byte *)buf + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 171         fccsize * i;
 172       supply_register (regcache, LOONGARCH_FIRST_FCC_REGNUM + i, regbuf);
 173     }
 174
 175   regbuf = (const gdb_byte *)buf + fprsize * LOONGARCH_LINUX_NUM_FPREGSET +
 176     fccsize * LOONGARCH_LINUX_NUM_FCC;
 177   supply_register (regcache, LOONGARCH_FCSR_REGNUM, regbuf);
 178 }
 179
 180 /* LoongArch/Linux regsets.  */
 181 static struct regset_info loongarch_regsets[] = {
 182   { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS, sizeof (elf_gregset_t),
 183     GENERAL_REGS, loongarch_fill_gregset, loongarch_store_gregset },
 184   { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET, sizeof (elf_fpregset_t),
 185     FP_REGS, loongarch_fill_fpregset, loongarch_store_fpregset },
 186   NULL_REGSET
 187 };
 188
 189 /* LoongArch/Linux regset information.  */
 190 static struct regsets_info loongarch_regsets_info =
 191   {
 192     loongarch_regsets, /* regsets */
 193     0, /* num_regsets */
 194     NULL, /* disabled_regsets */
 195   };
 196
 197 /* Definition of linux_target_ops data member "regs_info".  */
 198 static struct regs_info loongarch_regs =
 199   {
 200     NULL, /* regset_bitmap */
 201     NULL, /* usrregs */
 202     &loongarch_regsets_info,
 203   };
 204
 205 /* Implementation of linux target ops method "get_regs_info".  */
 206
 207 const regs_info *
 208 loongarch_target::get_regs_info ()
 209 {
 210   return &loongarch_regs;
 211 }
 212
 213 /* Implementation of linux target ops method "low_fetch_register".  */
 214
 215 bool
 216 loongarch_target::low_fetch_register (regcache *regcache, int regno)
 217 {
 218   if (regno != 0)
 219     return false;
 220   supply_register_zeroed (regcache, 0);
 221   return true;
 222 }
 223
 224 bool
 225 loongarch_target::low_supports_breakpoints ()
 226 {
 227   return true;
 228 }
 229
 230 /* Implementation of linux target ops method "low_get_pc".  */
 231
 232 CORE_ADDR
 233 loongarch_target::low_get_pc (regcache *regcache)
 234 {
 235   if (register_size (regcache->tdesc, 0) == 8)
 236     return linux_get_pc_64bit (regcache);
 237   else
 238     return linux_get_pc_32bit (regcache);
 239 }
 240
 241 /* Implementation of linux target ops method "low_set_pc".  */
 242
 243 void
 244 loongarch_target::low_set_pc (regcache *regcache, CORE_ADDR newpc)
 245 {
 246   if (register_size (regcache->tdesc, 0) == 8)
 247     linux_set_pc_64bit (regcache, newpc);
 248   else
 249     linux_set_pc_32bit (regcache, newpc);
 250 }
 251
 252 #define loongarch_breakpoint_len 4
 253
 254 /* LoongArch BRK software debug mode instruction.
 255    This instruction needs to match gdb/loongarch-tdep.c
 256    (loongarch_default_breakpoint).  */
 257 static const gdb_byte loongarch_breakpoint[] = {0x05, 0x00, 0x2a, 0x00};
 258
 259 /* Implementation of target ops method "breakpoint_kind_from_pc".  */
 260
 261 int
 262 loongarch_target::breakpoint_kind_from_pc (CORE_ADDR *pcptr)
 263 {
 264   return loongarch_breakpoint_len;
 265 }
 266
 267 /* Implementation of target ops method "sw_breakpoint_from_kind".  */
 268
 269 const gdb_byte *
 270 loongarch_target::sw_breakpoint_from_kind (int kind, int *size)
 271 {
 272   *size = loongarch_breakpoint_len;
 273   return (const gdb_byte *) &loongarch_breakpoint;
 274 }
 275
 276 /* Implementation of linux target ops method "low_breakpoint_at".  */
 277
 278 bool
 279 loongarch_target::low_breakpoint_at (CORE_ADDR pc)
 280 {
 281   gdb_byte insn[loongarch_breakpoint_len];
 282
 283   read_memory (pc, (unsigned char *) &insn, loongarch_breakpoint_len);
 284   if (memcmp (insn, loongarch_breakpoint, loongarch_breakpoint_len) == 0)
 285     return true;
 286
 287   return false;
 288 }
 289
 290 /* The linux target ops object.  */
 291
 292 linux_process_target *the_linux_target = &the_loongarch_target;
 293
 294 /* Initialize the LoongArch/Linux target.  */
 295
 296 void
 297 initialize_low_arch ()
 298 {
 299   initialize_regsets_info (&loongarch_regsets_info);
 300 }