gdb/aarch64-ravenscar-thread.c

   1 /* Ravenscar Aarch64 target support.
   2
   3    Copyright (C) 2017-2019 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 "gdbcore.h"
  22 #include "regcache.h"
  23 #include "aarch64-tdep.h"
  24 #include "inferior.h"
  25 #include "ravenscar-thread.h"
  26 #include "aarch64-ravenscar-thread.h"
  27 #include "gdbarch.h"
  28
  29 #define NO_OFFSET -1
  30
  31 /* See aarch64-tdep.h for register numbers.  */
  32
  33 static const int aarch64_context_offsets[] =
  34 {
  35   /* X0 - X28 */
  36   NO_OFFSET, NO_OFFSET, NO_OFFSET, NO_OFFSET,
  37   NO_OFFSET, NO_OFFSET, NO_OFFSET, NO_OFFSET,
  38   NO_OFFSET, NO_OFFSET, NO_OFFSET, NO_OFFSET,
  39   NO_OFFSET, NO_OFFSET, NO_OFFSET, NO_OFFSET,
  40   NO_OFFSET, NO_OFFSET, NO_OFFSET, 0,
  41   8,         16,        24,        32,
  42   40,        48,        56,        64,
  43   72,
  44
  45   /* FP, LR, SP, PC, CPSR */
  46   /* Note that as task switch is synchronous, PC is in fact the LR here */
  47   80,        88,        96,        88,
  48   NO_OFFSET,
  49
  50   /* Q0 - Q31 */
  51   112,       128,       144,       160,
  52   176,       192,       208,       224,
  53   240,       256,       272,       288,
  54   304,       320,       336,       352,
  55   368,       384,       400,       416,
  56   432,       448,       464,       480,
  57   496,       512,       528,       544,
  58   560,       576,       592,       608,
  59
  60   /* FPSR, FPCR */
  61   104,       108,
  62
  63   /* FPU Saved field */
  64   624
  65 };
  66
  67 /* The register layout info.  */
  68
  69 struct ravenscar_reg_info
  70 {
  71   /* A table providing the offset relative to the context structure
  72      where each register is saved.  */
  73   const int *context_offsets;
  74
  75   /* The number of elements in the context_offsets table above.  */
  76   int context_offsets_size;
  77 };
  78
  79 /* supply register REGNUM, which has been saved on REGISTER_ADDR, to the
  80    regcache.  */
  81
  82 static void
  83 supply_register_at_address (struct regcache *regcache, int regnum,
  84                             CORE_ADDR register_addr)
  85 {
  86   struct gdbarch *gdbarch = regcache->arch ();
  87   int buf_size = register_size (gdbarch, regnum);
  88   gdb_byte *buf;
  89
  90   buf = (gdb_byte *) alloca (buf_size);
  91   read_memory (register_addr, buf, buf_size);
  92   regcache->raw_supply (regnum, buf);
  93 }
  94
  95 /* Return true if, for a non-running thread, REGNUM has been saved on the
  96    Thread_Descriptor.  */
  97
  98 static int
  99 register_in_thread_descriptor_p (const struct ravenscar_reg_info *reg_info,
 100                                  int regnum)
 101 {
 102   /* Check FPU registers */
 103   return (regnum < reg_info->context_offsets_size
 104           && reg_info->context_offsets[regnum] != NO_OFFSET);
 105 }
 106
 107 /* to_fetch_registers when inferior_ptid is different from the running
 108    thread.  */
 109
 110 static void
 111 aarch64_ravenscar_generic_fetch_registers
 112   (const struct ravenscar_reg_info *reg_info,
 113    struct regcache *regcache, int regnum)
 114 {
 115   struct gdbarch *gdbarch = regcache->arch ();
 116   const int num_regs = gdbarch_num_regs (gdbarch);
 117   int current_regnum;
 118   CORE_ADDR current_address;
 119   CORE_ADDR thread_descriptor_address;
 120
 121   /* The tid is the thread_id field, which is a pointer to the thread.  */
 122   thread_descriptor_address = (CORE_ADDR) inferior_ptid.tid ();
 123
 124   /* Read registers.  */
 125   for (current_regnum = 0; current_regnum < num_regs; current_regnum++)
 126     {
 127       if (register_in_thread_descriptor_p (reg_info, current_regnum))
 128         {
 129           current_address = thread_descriptor_address
 130             + reg_info->context_offsets[current_regnum];
 131           supply_register_at_address (regcache, current_regnum,
 132                                       current_address);
 133         }
 134     }
 135 }
 136
 137 /* to_store_registers when inferior_ptid is different from the running
 138    thread.  */
 139
 140 static void
 141 aarch64_ravenscar_generic_store_registers
 142   (const struct ravenscar_reg_info *reg_info,
 143    struct regcache *regcache, int regnum)
 144 {
 145   struct gdbarch *gdbarch = regcache->arch ();
 146   int buf_size = register_size (gdbarch, regnum);
 147   gdb_byte buf[buf_size];
 148   ULONGEST register_address;
 149
 150   if (register_in_thread_descriptor_p (reg_info, regnum))
 151     register_address
 152       = inferior_ptid.tid () + reg_info->context_offsets [regnum];
 153   else
 154     return;
 155
 156   regcache->raw_collect (regnum, buf);
 157   write_memory (register_address,
 158                 buf,
 159                 buf_size);
 160 }
 161
 162 /* The ravenscar_reg_info for most Aarch64 targets.  */
 163
 164 static const struct ravenscar_reg_info aarch64_reg_info =
 165 {
 166   aarch64_context_offsets,
 167   ARRAY_SIZE (aarch64_context_offsets),
 168 };
 169
 170 struct aarch64_ravenscar_ops : public ravenscar_arch_ops
 171 {
 172   void fetch_registers (struct regcache *regcache, int regnum) override
 173   {
 174     aarch64_ravenscar_generic_fetch_registers
 175       (&aarch64_reg_info, regcache, regnum);
 176   }
 177
 178   void store_registers (struct regcache *regcache, int regnum) override
 179   {
 180     aarch64_ravenscar_generic_store_registers
 181       (&aarch64_reg_info, regcache, regnum);
 182   }
 183 };
 184
 185 /* The ravenscar_arch_ops vector for most Aarch64 targets.  */
 186
 187 static struct aarch64_ravenscar_ops aarch64_ravenscar_ops;
 188
 189 /* Register aarch64_ravenscar_ops in GDBARCH.  */
 190
 191 void
 192 register_aarch64_ravenscar_ops (struct gdbarch *gdbarch)
 193 {
 194   set_gdbarch_ravenscar_ops (gdbarch, &aarch64_ravenscar_ops);
 195 }