gdb/or1k-linux-tdep.c

   1 /* Target-dependent code for GNU/Linux on OpenRISC processors.
   2    Copyright (C) 2018-2020 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 "defs.h"
  20 #include "or1k-tdep.h"
  21 #include "osabi.h"
  22 #include "glibc-tdep.h"
  23 #include "linux-tdep.h"
  24 #include "solib-svr4.h"
  25 #include "regset.h"
  26 #include "tramp-frame.h"
  27 #include "trad-frame.h"
  28 #include "gdbarch.h"
  29
  30 /* Define the general register mapping.  The kernel puts the PC at offset 0,
  31    gdb puts it at offset 32.  Register x0 is always 0 and can be ignored.
  32    Registers x1 to x31 are in the same place.  */
  33
  34 static const struct regcache_map_entry or1k_linux_gregmap[] =
  35 {
  36   { 32, OR1K_ZERO_REGNUM, 4 }, /* r0 to r31 */
  37   { 1,  OR1K_NPC_REGNUM, 4 },
  38   { 0 }
  39 };
  40
  41 /* Define the general register regset.  */
  42
  43 static const struct regset or1k_linux_gregset =
  44 {
  45   or1k_linux_gregmap, regcache_supply_regset, regcache_collect_regset
  46 };
  47
  48 /* Define hook for core file support.  */
  49
  50 static void
  51 or1k_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
  52                                          iterate_over_regset_sections_cb *cb,
  53                                          void *cb_data,
  54                                          const struct regcache *regcache)
  55 {
  56   cb (".reg", (33 * 4), (33 * 4), &or1k_linux_gregset, NULL, cb_data);
  57 }
  58
  59 /* Signal trampoline support.  */
  60
  61 static void or1k_linux_sigframe_init (const struct tramp_frame *self,
  62                                        struct frame_info *this_frame,
  63                                        struct trad_frame_cache *this_cache,
  64                                        CORE_ADDR func);
  65
  66 #define OR1K_RT_SIGRETURN               139
  67
  68 #define OR1K_INST_L_ORI_R11_R0_IMM      0xa9600000
  69 #define OR1K_INST_L_SYS_1               0x20000001
  70 #define OR1K_INST_L_NOP                 0x15000000
  71
  72 static const struct tramp_frame or1k_linux_sigframe = {
  73   SIGTRAMP_FRAME,
  74   4,
  75   {
  76     { OR1K_INST_L_ORI_R11_R0_IMM | OR1K_RT_SIGRETURN, ULONGEST_MAX },
  77     { OR1K_INST_L_SYS_1, ULONGEST_MAX },
  78     { OR1K_INST_L_NOP, ULONGEST_MAX },
  79     { TRAMP_SENTINEL_INSN }
  80   },
  81   or1k_linux_sigframe_init,
  82   NULL
  83 };
  84
  85 /* Runtime signal frames look like this:
  86   struct rt_sigframe {
  87     struct siginfo info;
  88     struct ucontext uc;
  89     unsigned char retcode[16];
  90   };
  91
  92   struct ucontext {
  93     unsigned long     uc_flags;     - 4
  94     struct ucontext  *uc_link;      - 4
  95     stack_t           uc_stack;     - 4 * 3
  96     struct sigcontext uc_mcontext;
  97     sigset_t          uc_sigmask;
  98   };
  99
 100   struct sigcontext {
 101     struct user_regs_struct regs;
 102     unsigned long oldmask;
 103   };
 104
 105   struct user_regs_struct {
 106     unsigned long gpr[32];
 107     unsigned long pc;
 108     unsigned long sr;
 109   };  */
 110
 111 #define SIGFRAME_SIGINFO_SIZE           128
 112 #define UCONTEXT_MCONTEXT_OFFSET        20
 113
 114 static void
 115 or1k_linux_sigframe_init (const struct tramp_frame *self,
 116                            struct frame_info *this_frame,
 117                            struct trad_frame_cache *this_cache,
 118                            CORE_ADDR func)
 119 {
 120   CORE_ADDR frame_sp = get_frame_sp (this_frame);
 121   CORE_ADDR mcontext_base;
 122   CORE_ADDR regs_base;
 123
 124   mcontext_base = frame_sp + SIGFRAME_SIGINFO_SIZE + UCONTEXT_MCONTEXT_OFFSET;
 125
 126   /* Handle the general registers 0-31 followed by the PC.  */
 127   regs_base = mcontext_base;
 128   for (int i = 0; i < 32; i++)
 129     trad_frame_set_reg_addr (this_cache, OR1K_ZERO_REGNUM + i,
 130                              regs_base + (i * 4));
 131   trad_frame_set_reg_addr (this_cache, OR1K_NPC_REGNUM, regs_base + (32 * 4));
 132   trad_frame_set_reg_addr (this_cache, OR1K_SR_REGNUM, regs_base + (33 * 4));
 133
 134   /* Choice of the bottom of the sigframe is somewhat arbitrary.  */
 135   trad_frame_set_id (this_cache, frame_id_build (frame_sp, func));
 136 }
 137
 138 /* Initialize OpenRISC Linux ABI info.  */
 139
 140 static void
 141 or1k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 142 {
 143   linux_init_abi (info, gdbarch);
 144
 145   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 146                                          svr4_ilp32_fetch_link_map_offsets);
 147
 148   /* GNU/Linux uses SVR4-style shared libraries.  */
 149   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 150
 151   /* GNU/Linux uses the dynamic linker included in the GNU C Library.  */
 152   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 153
 154   /* Enable TLS support.  */
 155   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 156                                              svr4_fetch_objfile_link_map);
 157
 158   set_gdbarch_iterate_over_regset_sections
 159     (gdbarch, or1k_linux_iterate_over_regset_sections);
 160
 161   tramp_frame_prepend_unwinder (gdbarch, &or1k_linux_sigframe);
 162 }
 163
 164 /* Initialize OpenRISC Linux target support.  */
 165
 166 void
 167 _initialize_or1k_linux_tdep (void)
 168 {
 169   gdbarch_register_osabi (bfd_arch_or1k, 0, GDB_OSABI_LINUX,
 170                           or1k_linux_init_abi);
 171 }