gdbserver/linux-csky-low.cc

   1 /* GNU/Linux/MIPS specific low level interface, for the remote server for GDB.
   2    Copyright (C) 2022-2023 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 "tdesc.h"
  21 #include "linux-low.h"
  22 #include <sys/ptrace.h>
  23 #include "gdb_proc_service.h"
  24 #include <asm/ptrace.h>
  25 #include <elf.h>
  26 #include "arch/csky.h"
  27
  28 /* Linux target op definitions for the CSKY architecture.  */
  29
  30 class csky_target : public linux_process_target
  31 {
  32 public:
  33
  34   const regs_info *get_regs_info () override;
  35
  36   const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override;
  37
  38   bool supports_z_point_type (char z_type) override;
  39
  40   bool supports_hardware_single_step () override;
  41
  42 protected:
  43
  44   void low_arch_setup () override;
  45
  46   bool low_cannot_fetch_register (int regno) override;
  47
  48   bool low_cannot_store_register (int regno) 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 csky_target the_csky_target;
  60
  61 /* Return the ptrace "address" of register REGNO.  */
  62 static int csky_regmap[] = {
  63    0*4,  1*4,  2*4,  3*4,  4*4,  5*4,  6*4,  7*4,
  64    8*4,  9*4, 10*4, 11*4, 12*4, 13*4, 14*4, 15*4,
  65   16*4, 17*4, 18*4, 19*4, 20*4, 21*4, 22*4, 23*4,
  66   24*4, 25*4, 26*4, 27*4, 28*4, 29*4, 30*4, 31*4,
  67     -1,   -1,   -1,   -1, 34*4, 35*4,   -1,   -1,
  68   40*4, 42*4, 44*4, 46*4, 48*4, 50*4, 52*4, 54*4, /* fr0 ~ fr15, 64bit  */
  69   56*4, 58*4, 60*4, 62*4, 64*4, 66*4, 68*4, 70*4,
  70   72*4, 76*4, 80*4, 84*4, 88*4, 92*4, 96*4,100*4, /* vr0 ~ vr15, 128bit  */
  71  104*4,108*4,112*4,116*4,120*4,124*4,128*4,132*4,
  72   33*4,  /* pc  */
  73     -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
  74     -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
  75   32*4,   -1,   -1,   -1,   -1,   -1,   -1,   -1, /* psr  */
  76     -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
  77     -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
  78     -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
  79   73*4, 72*4, 74*4,   -1,   -1,   -1, 14*4,  /* fcr, fid, fesr, usp  */
  80 };
  81
  82 /* CSKY software breakpoint instruction code.  */
  83
  84 /* When the kernel code version is behind v4.x,
  85    illegal insn 0x1464 will be a software bkpt trigger.
  86    When an illegal insn exception happens, the case
  87    that insn at EPC is 0x1464 will be recognized as SIGTRAP.  */
  88 static unsigned short csky_breakpoint_illegal_2_v2 = 0x1464;
  89 static unsigned int csky_breakpoint_illegal_4_v2 = 0x14641464;
  90
  91 bool
  92 csky_target::low_cannot_fetch_register (int regno)
  93 {
  94   if (csky_regmap[regno] == -1)
  95     return true;
  96
  97   return false;
  98 }
  99
 100 bool
 101 csky_target::low_cannot_store_register (int regno)
 102 {
 103   if (csky_regmap[regno] == -1)
 104     return true;
 105
 106   return false;
 107 }
 108
 109 /* Get the value of pc register.  */
 110
 111 CORE_ADDR
 112 csky_target::low_get_pc (struct regcache *regcache)
 113 {
 114   unsigned long pc;
 115   collect_register_by_name (regcache, "pc", &pc);
 116   return pc;
 117 }
 118
 119 /* Set pc register.  */
 120
 121 void
 122 csky_target::low_set_pc (struct regcache *regcache, CORE_ADDR pc)
 123 {
 124   unsigned long new_pc = pc;
 125   supply_register_by_name (regcache, "pc", &new_pc);
 126 }
 127
 128
 129 void
 130 csky_target::low_arch_setup ()
 131 {
 132   static const char *expedite_regs[] = { "r14", "pc", NULL };
 133   target_desc_up tdesc = csky_create_target_description ();
 134
 135   if (!tdesc->expedite_regs)
 136     init_target_desc (tdesc.get (), expedite_regs);
 137
 138   current_process ()->tdesc = tdesc.release ();
 139
 140   return;
 141 }
 142
 143 /* Fetch the thread-local storage pointer for libthread_db.  */
 144
 145 ps_err_e
 146 ps_get_thread_area (struct ps_prochandle *ph,
 147                     lwpid_t lwpid, int idx, void **base)
 148 {
 149   struct pt_regs regset;
 150   if (ptrace (PTRACE_GETREGSET, lwpid,
 151               (PTRACE_TYPE_ARG3) (long) NT_PRSTATUS, &regset) != 0)
 152     return PS_ERR;
 153
 154   *base = (void *) regset.tls;
 155
 156   /* IDX is the bias from the thread pointer to the beginning of the
 157      thread descriptor.  It has to be subtracted due to implementation
 158      quirks in libthread_db.  */
 159   *base = (void *) ((char *)*base - idx);
 160
 161   return PS_OK;
 162 }
 163
 164 /* Gdbserver uses PTRACE_GET/SET_RGESET.  */
 165
 166 static void
 167 csky_fill_pt_gregset (struct regcache *regcache, void *buf)
 168 {
 169   int i, base;
 170   struct pt_regs *regset = (struct pt_regs *)buf;
 171
 172   collect_register_by_name (regcache, "r15",  &regset->lr);
 173   collect_register_by_name (regcache, "pc", &regset->pc);
 174   collect_register_by_name (regcache, "psr", &regset->sr);
 175   collect_register_by_name (regcache, "r14", &regset->usp);
 176
 177   collect_register_by_name (regcache, "r0", &regset->a0);
 178   collect_register_by_name (regcache, "r1", &regset->a1);
 179   collect_register_by_name (regcache, "r2", &regset->a2);
 180   collect_register_by_name (regcache, "r3", &regset->a3);
 181
 182   base = find_regno (regcache->tdesc, "r4");
 183
 184   for (i = 0; i < 10; i++)
 185     collect_register (regcache, base + i,   &regset->regs[i]);
 186
 187   base = find_regno (regcache->tdesc, "r16");
 188   for (i = 0; i < 16; i++)
 189     collect_register (regcache, base + i,   &regset->exregs[i]);
 190
 191   collect_register_by_name (regcache, "hi", &regset->rhi);
 192   collect_register_by_name (regcache, "lo", &regset->rlo);
 193 }
 194
 195 static void
 196 csky_store_pt_gregset (struct regcache *regcache, const void *buf)
 197 {
 198   int i, base;
 199   const struct pt_regs *regset = (const struct pt_regs *) buf;
 200
 201   supply_register_by_name (regcache, "r15",  &regset->lr);
 202   supply_register_by_name (regcache, "pc", &regset->pc);
 203   supply_register_by_name (regcache, "psr", &regset->sr);
 204   supply_register_by_name (regcache, "r14", &regset->usp);
 205
 206   supply_register_by_name (regcache, "r0", &regset->a0);
 207   supply_register_by_name (regcache, "r1", &regset->a1);
 208   supply_register_by_name (regcache, "r2", &regset->a2);
 209   supply_register_by_name (regcache, "r3", &regset->a3);
 210
 211   base = find_regno (regcache->tdesc, "r4");
 212
 213   for (i = 0; i < 10; i++)
 214     supply_register (regcache, base + i,   &regset->regs[i]);
 215
 216   base = find_regno (regcache->tdesc, "r16");
 217   for (i = 0; i < 16; i++)
 218     supply_register (regcache, base + i,   &regset->exregs[i]);
 219
 220   supply_register_by_name (regcache, "hi", &regset->rhi);
 221   supply_register_by_name (regcache, "lo", &regset->rlo);
 222 }
 223
 224 static void
 225 csky_fill_pt_vrregset (struct regcache *regcache, void *buf)
 226 {
 227   int i, base;
 228   struct user_fp *regset = (struct user_fp *)buf;
 229
 230   base = find_regno (regcache->tdesc, "vr0");
 231
 232   for (i = 0; i < 16; i++)
 233     collect_register (regcache, base + i, &regset->vr[i * 4]);
 234   collect_register_by_name (regcache, "fcr", &regset->fcr);
 235   collect_register_by_name (regcache, "fesr", &regset->fesr);
 236   collect_register_by_name (regcache, "fid", &regset->fid);
 237 }
 238
 239
 240 static void
 241 csky_store_pt_vrregset (struct regcache *regcache, const void *buf)
 242 {
 243   int i, base;
 244   const struct user_fp *regset = (const struct user_fp *)buf;
 245
 246   base = find_regno (regcache->tdesc, "vr0");
 247
 248   for (i = 0; i < 16; i++)
 249     supply_register (regcache, base + i, &regset->vr[i * 4]);
 250
 251   base = find_regno (regcache->tdesc, "fr0");
 252
 253   for (i = 0; i < 16; i++)
 254     supply_register (regcache, base + i, &regset->vr[i * 4]);
 255   supply_register_by_name (regcache, "fcr", &regset->fcr);
 256   supply_register_by_name (regcache, "fesr", &regset->fesr);
 257   supply_register_by_name (regcache, "fid", &regset->fid);
 258 }
 259
 260 struct regset_info csky_regsets[] = {
 261   { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_PRSTATUS, sizeof(struct pt_regs),
 262     GENERAL_REGS, csky_fill_pt_gregset, csky_store_pt_gregset},
 263
 264   { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_FPREGSET, sizeof(struct user_fp),
 265     FP_REGS, csky_fill_pt_vrregset, csky_store_pt_vrregset},
 266   NULL_REGSET
 267 };
 268
 269
 270 static struct regsets_info csky_regsets_info =
 271 {
 272   csky_regsets, /* Regsets  */
 273   0,            /* Num_regsets  */
 274   NULL,         /* Disabled_regsets  */
 275 };
 276
 277
 278 static struct regs_info csky_regs_info =
 279 {
 280   NULL, /* FIXME: what's this  */
 281   NULL, /* PEEKUSER/PORKUSR isn't supported by kernel > 4.x */
 282   &csky_regsets_info
 283 };
 284
 285
 286 const regs_info *
 287 csky_target::get_regs_info ()
 288 {
 289   return &csky_regs_info;
 290 }
 291
 292 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
 293
 294 const gdb_byte *
 295 csky_target::sw_breakpoint_from_kind (int kind, int *size)
 296 {
 297   if (kind == 4)
 298     {
 299       *size = 4;
 300       return (const gdb_byte *) &csky_breakpoint_illegal_4_v2;
 301     }
 302   else
 303     {
 304       *size = 2;
 305       return (const gdb_byte *) &csky_breakpoint_illegal_2_v2;
 306     }
 307 }
 308
 309 bool
 310 csky_target::supports_z_point_type (char z_type)
 311 {
 312   /* FIXME: hardware breakpoint support ??  */
 313   if (z_type == Z_PACKET_SW_BP)
 314     return true;
 315
 316   return false;
 317 }
 318
 319 bool
 320 csky_target::low_breakpoint_at (CORE_ADDR where)
 321 {
 322   unsigned int insn;
 323
 324   /* Here just read 2 bytes, as csky_breakpoint_illegal_4_v2
 325      is double of csky_breakpoint_illegal_2_v2, csky_breakpoint_bkpt_4
 326      is double of csky_breakpoint_bkpt_2. Others are 2 bytes bkpt.  */
 327   read_memory (where, (unsigned char *) &insn, 2);
 328
 329   if (insn == csky_breakpoint_illegal_2_v2)
 330     return true;
 331
 332   return false;
 333 }
 334
 335 /* Support for hardware single step.  */
 336
 337 bool
 338 csky_target::supports_hardware_single_step ()
 339 {
 340   return true;
 341 }
 342
 343 /* The linux target ops object.  */
 344
 345 linux_process_target *the_linux_target = &the_csky_target;
 346
 347 void
 348 initialize_low_arch (void)
 349 {
 350   initialize_regsets_info (&csky_regsets_info);
 351 }