gdbserver/linux-cris-low.cc

   1 /* GNU/Linux/CRIS specific low level interface, for the remote server for GDB.
   2    Copyright (C) 1995-2020 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 "nat/gdb_ptrace.h"
  22
  23 /* Linux target op definitions for the CRIS architecture.  */
  24
  25 class cris_target : public linux_process_target
  26 {
  27 public:
  28
  29   const regs_info *get_regs_info () override;
  30
  31 protected:
  32
  33   void low_arch_setup () override;
  34
  35   bool low_cannot_fetch_register (int regno) override;
  36
  37   bool low_cannot_store_register (int regno) override;
  38
  39   bool low_supports_breakpoints () override;
  40
  41   CORE_ADDR low_get_pc (regcache *regcache) override;
  42
  43   void low_set_pc (regcache *regcache, CORE_ADDR newpc) override;
  44 };
  45
  46 /* The singleton target ops object.  */
  47
  48 static cris_target the_cris_target;
  49
  50 bool
  51 cris_target::low_supports_breakpoints ()
  52 {
  53   return true;
  54 }
  55
  56 CORE_ADDR
  57 cris_target::low_get_pc (regcache *regcache)
  58 {
  59   return linux_get_pc_32bit (regcache);
  60 }
  61
  62 void
  63 cris_target::low_set_pc (regcache *regcache, CORE_ADDR pc)
  64 {
  65   linux_set_pc_32bit (regcache, pc);
  66 }
  67
  68 /* Defined in auto-generated file reg-cris.c.  */
  69 void init_registers_cris (void);
  70 extern const struct target_desc *tdesc_cris;
  71
  72 /* CRISv10 */
  73 #define cris_num_regs 32
  74
  75 /* Locations need to match <include/asm/arch/ptrace.h>.  */
  76 static int cris_regmap[] = {
  77   15*4, 14*4, 13*4, 12*4,
  78   11*4, 10*4, 9*4, 8*4,
  79   7*4, 6*4, 5*4, 4*4,
  80   3*4, 2*4, 23*4, 19*4,
  81
  82   -1, -1, -1, -1,
  83   -1, 17*4, -1, 16*4,
  84   -1, -1, -1, 18*4,
  85   -1, 17*4, -1, -1
  86
  87 };
  88
  89 bool
  90 cris_target::low_cannot_store_register (int regno)
  91 {
  92   if (cris_regmap[regno] == -1)
  93     return true;
  94
  95   return (regno >= cris_num_regs);
  96 }
  97
  98 bool
  99 cris_target::low_cannot_fetch_register (int regno)
 100 {
 101   if (cris_regmap[regno] == -1)
 102     return true;
 103
 104   return (regno >= cris_num_regs);
 105 }
 106
 107 static const unsigned short cris_breakpoint = 0xe938;
 108 #define cris_breakpoint_len 2
 109
 110 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
 111
 112 static const gdb_byte *
 113 cris_sw_breakpoint_from_kind (int kind, int *size)
 114 {
 115   *size = cris_breakpoint_len;
 116   return (const gdb_byte *) &cris_breakpoint;
 117 }
 118
 119 static int
 120 cris_breakpoint_at (CORE_ADDR where)
 121 {
 122   unsigned short insn;
 123
 124   the_target->read_memory (where, (unsigned char *) &insn,
 125                            cris_breakpoint_len);
 126   if (insn == cris_breakpoint)
 127     return 1;
 128
 129   /* If necessary, recognize more trap instructions here.  GDB only uses the
 130      one.  */
 131   return 0;
 132 }
 133
 134 void
 135 cris_target::low_arch_setup ()
 136 {
 137   current_process ()->tdesc = tdesc_cris;
 138 }
 139
 140 static struct usrregs_info cris_usrregs_info =
 141   {
 142     cris_num_regs,
 143     cris_regmap,
 144   };
 145
 146 static struct regs_info myregs_info =
 147   {
 148     NULL, /* regset_bitmap */
 149     &cris_usrregs_info,
 150   };
 151
 152 const regs_info *
 153 cris_target::get_regs_info ()
 154 {
 155   return &myregs_info;
 156 }
 157
 158 struct linux_target_ops the_low_target = {
 159   NULL, /* breakpoint_kind_from_pc */
 160   cris_sw_breakpoint_from_kind,
 161   NULL, /* get_next_pcs */
 162   0,
 163   cris_breakpoint_at,
 164 };
 165
 166 /* The linux target ops object.  */
 167
 168 linux_process_target *the_linux_target = &the_cris_target;
 169
 170 void
 171 initialize_low_arch (void)
 172 {
 173   init_registers_cris ();
 174 }