gdb/arm-netbsd-tdep.c

   1 /* Target-dependent code for NetBSD/arm.
   2
   3    Copyright (C) 2002-2024 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 "osabi.h"
  21
  22 #include "arch/arm.h"
  23 #include "arm-netbsd-tdep.h"
  24 #include "netbsd-tdep.h"
  25 #include "arm-tdep.h"
  26 #include "regset.h"
  27 #include "solib-svr4.h"
  28
  29 /* Description of the longjmp buffer.  */
  30 #define ARM_NBSD_JB_PC 24
  31 #define ARM_NBSD_JB_ELEMENT_SIZE ARM_INT_REGISTER_SIZE
  32
  33 /* For compatibility with previous implementations of GDB on arm/NetBSD,
  34    override the default little-endian breakpoint.  */
  35 static const gdb_byte arm_nbsd_arm_le_breakpoint[] = {0x11, 0x00, 0x00, 0xe6};
  36 static const gdb_byte arm_nbsd_arm_be_breakpoint[] = {0xe6, 0x00, 0x00, 0x11};
  37 static const gdb_byte arm_nbsd_thumb_le_breakpoint[] = {0xfe, 0xde};
  38 static const gdb_byte arm_nbsd_thumb_be_breakpoint[] = {0xde, 0xfe};
  39
  40 /* This matches struct reg from NetBSD's sys/arch/arm/include/reg.h:
  41    https://github.com/NetBSD/src/blob/7c13e6e6773bb171f4ed3ed53013e9d24b3c1eac/sys/arch/arm/include/reg.h#L39
  42  */
  43 struct arm_nbsd_reg
  44 {
  45   uint32_t reg[13];
  46   uint32_t sp;
  47   uint32_t lr;
  48   uint32_t pc;
  49   uint32_t cpsr;
  50 };
  51
  52 void
  53 arm_nbsd_supply_gregset (const struct regset *regset, struct regcache *regcache,
  54                          int regnum, const void *gregs, size_t len)
  55 {
  56   const arm_nbsd_reg *gregset = static_cast<const arm_nbsd_reg *>(gregs);
  57   gdb_assert (len >= sizeof (arm_nbsd_reg));
  58
  59   /* Integer registers.  */
  60   for (int i = ARM_A1_REGNUM; i < ARM_SP_REGNUM; i++)
  61     if (regnum == -1 || regnum == i)
  62       regcache->raw_supply (i, (char *) &gregset->reg[i]);
  63
  64   if (regnum == -1 || regnum == ARM_SP_REGNUM)
  65     regcache->raw_supply (ARM_SP_REGNUM, (char *) &gregset->sp);
  66
  67   if (regnum == -1 || regnum == ARM_LR_REGNUM)
  68     regcache->raw_supply (ARM_LR_REGNUM, (char *) &gregset->lr);
  69
  70   if (regnum == -1 || regnum == ARM_PC_REGNUM)
  71     {
  72       CORE_ADDR r_pc = gdbarch_addr_bits_remove (regcache->arch (), gregset->pc);
  73       regcache->raw_supply (ARM_PC_REGNUM, (char *) &r_pc);
  74     }
  75
  76   if (regnum == -1 || regnum == ARM_PS_REGNUM)
  77     {
  78       if (arm_apcs_32)
  79         regcache->raw_supply (ARM_PS_REGNUM, (char *) &gregset->cpsr);
  80       else
  81         regcache->raw_supply (ARM_PS_REGNUM, (char *) &gregset->pc);
  82     }
  83 }
  84
  85 static const struct regset arm_nbsd_regset = {
  86   nullptr,
  87   arm_nbsd_supply_gregset,
  88   /* We don't need a collect function because we only use this reading registers
  89      (via iterate_over_regset_sections and fetch_regs/fetch_register).  */
  90   nullptr,
  91   0
  92 };
  93
  94 static void
  95 arm_nbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
  96                                        iterate_over_regset_sections_cb *cb,
  97                                        void *cb_data,
  98                                        const struct regcache *regcache)
  99 {
 100   cb (".reg", sizeof (arm_nbsd_reg), sizeof (arm_nbsd_reg), &arm_nbsd_regset,
 101       NULL, cb_data);
 102   /* cbiesinger/2020-02-12 -- as far as I can tell, ARM/NetBSD does
 103      not write any floating point registers into the core file (tested
 104      with NetBSD 9.1_RC1).  When it does, this function will need to read them,
 105      and the arm-netbsd gdbarch will need a core_read_description function
 106      to return the right description for them.  */
 107 }
 108
 109 static void
 110 arm_netbsd_init_abi_common (struct gdbarch_info info,
 111                             struct gdbarch *gdbarch)
 112 {
 113   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 114
 115   tdep->lowest_pc = 0x8000;
 116   switch (info.byte_order)
 117     {
 118     case BFD_ENDIAN_LITTLE:
 119       tdep->arm_breakpoint = arm_nbsd_arm_le_breakpoint;
 120       tdep->thumb_breakpoint = arm_nbsd_thumb_le_breakpoint;
 121       tdep->arm_breakpoint_size = sizeof (arm_nbsd_arm_le_breakpoint);
 122       tdep->thumb_breakpoint_size = sizeof (arm_nbsd_thumb_le_breakpoint);
 123       break;
 124
 125     case BFD_ENDIAN_BIG:
 126       tdep->arm_breakpoint = arm_nbsd_arm_be_breakpoint;
 127       tdep->thumb_breakpoint = arm_nbsd_thumb_be_breakpoint;
 128       tdep->arm_breakpoint_size = sizeof (arm_nbsd_arm_be_breakpoint);
 129       tdep->thumb_breakpoint_size = sizeof (arm_nbsd_thumb_be_breakpoint);
 130       break;
 131
 132     default:
 133       internal_error (_("arm_gdbarch_init: bad byte order for float format"));
 134     }
 135
 136   tdep->jb_pc = ARM_NBSD_JB_PC;
 137   tdep->jb_elt_size = ARM_NBSD_JB_ELEMENT_SIZE;
 138
 139   set_gdbarch_iterate_over_regset_sections
 140     (gdbarch, arm_nbsd_iterate_over_regset_sections);
 141   /* Single stepping.  */
 142   set_gdbarch_software_single_step (gdbarch, arm_software_single_step);
 143 }
 144
 145 static void
 146 arm_netbsd_elf_init_abi (struct gdbarch_info info,
 147                          struct gdbarch *gdbarch)
 148 {
 149   arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 150
 151   arm_netbsd_init_abi_common (info, gdbarch);
 152
 153   nbsd_init_abi (info, gdbarch);
 154
 155   if (tdep->fp_model == ARM_FLOAT_AUTO)
 156     tdep->fp_model = ARM_FLOAT_SOFT_VFP;
 157
 158   /* NetBSD ELF uses SVR4-style shared libraries.  */
 159   set_solib_svr4_fetch_link_map_offsets
 160     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 161 }
 162
 163 void _initialize_arm_netbsd_tdep ();
 164 void
 165 _initialize_arm_netbsd_tdep ()
 166 {
 167   gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_NETBSD,
 168                           arm_netbsd_elf_init_abi);
 169 }