gdb/arm-netbsd-tdep.c

   1 /* Target-dependent code for NetBSD/arm.
   2
   3    Copyright (C) 2002-2023 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 "defs.h"
  21 #include "osabi.h"
  22
  23 #include "arch/arm.h"
  24 #include "arm-netbsd-tdep.h"
  25 #include "netbsd-tdep.h"
  26 #include "arm-tdep.h"
  27 #include "regset.h"
  28 #include "solib-svr4.h"
  29
  30 /* Description of the longjmp buffer.  */
  31 #define ARM_NBSD_JB_PC 24
  32 #define ARM_NBSD_JB_ELEMENT_SIZE ARM_INT_REGISTER_SIZE
  33
  34 /* For compatibility with previous implementations of GDB on arm/NetBSD,
  35    override the default little-endian breakpoint.  */
  36 static const gdb_byte arm_nbsd_arm_le_breakpoint[] = {0x11, 0x00, 0x00, 0xe6};
  37 static const gdb_byte arm_nbsd_arm_be_breakpoint[] = {0xe6, 0x00, 0x00, 0x11};
  38 static const gdb_byte arm_nbsd_thumb_le_breakpoint[] = {0xfe, 0xde};
  39 static const gdb_byte arm_nbsd_thumb_be_breakpoint[] = {0xde, 0xfe};
  40
  41 /* This matches struct reg from NetBSD's sys/arch/arm/include/reg.h:
  42    https://github.com/NetBSD/src/blob/7c13e6e6773bb171f4ed3ed53013e9d24b3c1eac/sys/arch/arm/include/reg.h#L39
  43  */
  44 struct arm_nbsd_reg
  45 {
  46   uint32_t reg[13];
  47   uint32_t sp;
  48   uint32_t lr;
  49   uint32_t pc;
  50   uint32_t cpsr;
  51 };
  52
  53 void
  54 arm_nbsd_supply_gregset (const struct regset *regset, struct regcache *regcache,
  55                          int regnum, const void *gregs, size_t len)
  56 {
  57   const arm_nbsd_reg *gregset = static_cast<const arm_nbsd_reg *>(gregs);
  58   gdb_assert (len >= sizeof (arm_nbsd_reg));
  59
  60   /* Integer registers.  */
  61   for (int i = ARM_A1_REGNUM; i < ARM_SP_REGNUM; i++)
  62     if (regnum == -1 || regnum == i)
  63       regcache->raw_supply (i, (char *) &gregset->reg[i]);
  64
  65   if (regnum == -1 || regnum == ARM_SP_REGNUM)
  66     regcache->raw_supply (ARM_SP_REGNUM, (char *) &gregset->sp);
  67
  68   if (regnum == -1 || regnum == ARM_LR_REGNUM)
  69     regcache->raw_supply (ARM_LR_REGNUM, (char *) &gregset->lr);
  70
  71   if (regnum == -1 || regnum == ARM_PC_REGNUM)
  72     {
  73       CORE_ADDR r_pc = gdbarch_addr_bits_remove (regcache->arch (), gregset->pc);
  74       regcache->raw_supply (ARM_PC_REGNUM, (char *) &r_pc);
  75     }
  76
  77   if (regnum == -1 || regnum == ARM_PS_REGNUM)
  78     {
  79       if (arm_apcs_32)
  80         regcache->raw_supply (ARM_PS_REGNUM, (char *) &gregset->cpsr);
  81       else
  82         regcache->raw_supply (ARM_PS_REGNUM, (char *) &gregset->pc);
  83     }
  84 }
  85
  86 static const struct regset arm_nbsd_regset = {
  87   nullptr,
  88   arm_nbsd_supply_gregset,
  89   /* We don't need a collect function because we only use this reading registers
  90      (via iterate_over_regset_sections and fetch_regs/fetch_register).  */
  91   nullptr,
  92   0
  93 };
  94
  95 static void
  96 arm_nbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
  97                                        iterate_over_regset_sections_cb *cb,
  98                                        void *cb_data,
  99                                        const struct regcache *regcache)
 100 {
 101   cb (".reg", sizeof (arm_nbsd_reg), sizeof (arm_nbsd_reg), &arm_nbsd_regset,
 102       NULL, cb_data);
 103   /* cbiesinger/2020-02-12 -- as far as I can tell, ARM/NetBSD does
 104      not write any floating point registers into the core file (tested
 105      with NetBSD 9.1_RC1).  When it does, this function will need to read them,
 106      and the arm-netbsd gdbarch will need a core_read_description function
 107      to return the right description for them.  */
 108 }
 109
 110 static void
 111 arm_netbsd_init_abi_common (struct gdbarch_info info,
 112                             struct gdbarch *gdbarch)
 113 {
 114   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 115
 116   tdep->lowest_pc = 0x8000;
 117   switch (info.byte_order)
 118     {
 119     case BFD_ENDIAN_LITTLE:
 120       tdep->arm_breakpoint = arm_nbsd_arm_le_breakpoint;
 121       tdep->thumb_breakpoint = arm_nbsd_thumb_le_breakpoint;
 122       tdep->arm_breakpoint_size = sizeof (arm_nbsd_arm_le_breakpoint);
 123       tdep->thumb_breakpoint_size = sizeof (arm_nbsd_thumb_le_breakpoint);
 124       break;
 125
 126     case BFD_ENDIAN_BIG:
 127       tdep->arm_breakpoint = arm_nbsd_arm_be_breakpoint;
 128       tdep->thumb_breakpoint = arm_nbsd_thumb_be_breakpoint;
 129       tdep->arm_breakpoint_size = sizeof (arm_nbsd_arm_be_breakpoint);
 130       tdep->thumb_breakpoint_size = sizeof (arm_nbsd_thumb_be_breakpoint);
 131       break;
 132
 133     default:
 134       internal_error (_("arm_gdbarch_init: bad byte order for float format"));
 135     }
 136
 137   tdep->jb_pc = ARM_NBSD_JB_PC;
 138   tdep->jb_elt_size = ARM_NBSD_JB_ELEMENT_SIZE;
 139
 140   set_gdbarch_iterate_over_regset_sections
 141     (gdbarch, arm_nbsd_iterate_over_regset_sections);
 142   /* Single stepping.  */
 143   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 144 }
 145
 146 static void
 147 arm_netbsd_elf_init_abi (struct gdbarch_info info,
 148                          struct gdbarch *gdbarch)
 149 {
 150   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 151
 152   arm_netbsd_init_abi_common (info, gdbarch);
 153
 154   nbsd_init_abi (info, gdbarch);
 155
 156   if (tdep->fp_model == ARM_FLOAT_AUTO)
 157     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 158
 159   /* NetBSD ELF uses SVR4-style shared libraries.  */
 160   set_solib_svr4_fetch_link_map_offsets
 161     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 162 }
 163
 164 void _initialize_arm_netbsd_tdep ();
 165 void
 166 _initialize_arm_netbsd_tdep ()
 167 {
 168   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_NETBSD,
 169                           arm_netbsd_elf_init_abi);
 170 }