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
  40 /* The singleton target ops object.  */
  41
  42 static cris_target the_cris_target;
  43
  44 /* Defined in auto-generated file reg-cris.c.  */
  45 void init_registers_cris (void);
  46 extern const struct target_desc *tdesc_cris;
  47
  48 /* CRISv10 */
  49 #define cris_num_regs 32
  50
  51 /* Locations need to match <include/asm/arch/ptrace.h>.  */
  52 static int cris_regmap[] = {
  53   15*4, 14*4, 13*4, 12*4,
  54   11*4, 10*4, 9*4, 8*4,
  55   7*4, 6*4, 5*4, 4*4,
  56   3*4, 2*4, 23*4, 19*4,
  57
  58   -1, -1, -1, -1,
  59   -1, 17*4, -1, 16*4,
  60   -1, -1, -1, 18*4,
  61   -1, 17*4, -1, -1
  62
  63 };
  64
  65 bool
  66 cris_target::low_cannot_store_register (int regno)
  67 {
  68   if (cris_regmap[regno] == -1)
  69     return true;
  70
  71   return (regno >= cris_num_regs);
  72 }
  73
  74 bool
  75 cris_target::low_cannot_fetch_register (int regno)
  76 {
  77   if (cris_regmap[regno] == -1)
  78     return true;
  79
  80   return (regno >= cris_num_regs);
  81 }
  82
  83 static const unsigned short cris_breakpoint = 0xe938;
  84 #define cris_breakpoint_len 2
  85
  86 /* Implementation of linux_target_ops method "sw_breakpoint_from_kind".  */
  87
  88 static const gdb_byte *
  89 cris_sw_breakpoint_from_kind (int kind, int *size)
  90 {
  91   *size = cris_breakpoint_len;
  92   return (const gdb_byte *) &cris_breakpoint;
  93 }
  94
  95 static int
  96 cris_breakpoint_at (CORE_ADDR where)
  97 {
  98   unsigned short insn;
  99
 100   the_target->read_memory (where, (unsigned char *) &insn,
 101                            cris_breakpoint_len);
 102   if (insn == cris_breakpoint)
 103     return 1;
 104
 105   /* If necessary, recognize more trap instructions here.  GDB only uses the
 106      one.  */
 107   return 0;
 108 }
 109
 110 void
 111 cris_target::low_arch_setup ()
 112 {
 113   current_process ()->tdesc = tdesc_cris;
 114 }
 115
 116 static struct usrregs_info cris_usrregs_info =
 117   {
 118     cris_num_regs,
 119     cris_regmap,
 120   };
 121
 122 static struct regs_info myregs_info =
 123   {
 124     NULL, /* regset_bitmap */
 125     &cris_usrregs_info,
 126   };
 127
 128 const regs_info *
 129 cris_target::get_regs_info ()
 130 {
 131   return &myregs_info;
 132 }
 133
 134 struct linux_target_ops the_low_target = {
 135   linux_get_pc_32bit,
 136   linux_set_pc_32bit,
 137   NULL, /* breakpoint_kind_from_pc */
 138   cris_sw_breakpoint_from_kind,
 139   NULL, /* get_next_pcs */
 140   0,
 141   cris_breakpoint_at,
 142 };
 143
 144 /* The linux target ops object.  */
 145
 146 linux_process_target *the_linux_target = &the_cris_target;
 147
 148 void
 149 initialize_low_arch (void)
 150 {
 151   init_registers_cris ();
 152 }