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      1 /* Low level interface to valgrind, for the remote server for GDB integrated
      2    in valgrind.
      3    Copyright (C) 2011
      4    Free Software Foundation, Inc.
      5 
      6    This file is part of VALGRIND.
      7    It has been inspired from a file from gdbserver in gdb 6.6.
      8 
      9    This program is free software; you can redistribute it and/or modify
     10    it under the terms of the GNU General Public License as published by
     11    the Free Software Foundation; either version 2 of the License, or
     12    (at your option) any later version.
     13 
     14    This program is distributed in the hope that it will be useful,
     15    but WITHOUT ANY WARRANTY; without even the implied warranty of
     16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     17    GNU General Public License for more details.
     18 
     19    You should have received a copy of the GNU General Public License
     20    along with this program; if not, write to the Free Software
     21    Foundation, Inc., 51 Franklin Street, Fifth Floor,
     22    Boston, MA 02110-1301, USA.  */
     23 
     24 #include "server.h"
     25 #include "target.h"
     26 #include "regdef.h"
     27 #include "regcache.h"
     28 
     29 #include "pub_core_machine.h"
     30 #include "pub_core_threadstate.h"
     31 #include "pub_core_transtab.h"
     32 #include "pub_core_gdbserver.h"
     33 #include "pub_core_debuginfo.h"
     34 
     35 #include "valgrind_low.h"
     36 
     37 #include "libvex_guest_arm.h"
     38 
     39 static struct reg regs[] = {
     40   { "r0", 0, 32 },
     41   { "r1", 32, 32 },
     42   { "r2", 64, 32 },
     43   { "r3", 96, 32 },
     44   { "r4", 128, 32 },
     45   { "r5", 160, 32 },
     46   { "r6", 192, 32 },
     47   { "r7", 224, 32 },
     48   { "r8", 256, 32 },
     49   { "r9", 288, 32 },
     50   { "r10", 320, 32 },
     51   { "r11", 352, 32 },
     52   { "r12", 384, 32 },
     53   { "sp", 416, 32 },
     54   { "lr", 448, 32 },
     55   { "pc", 480, 32 },
     56   { "", 512, 0 }, // It seems these entries are needed
     57   { "", 512, 0 }, // as previous versions of arm <-> gdb placed
     58   { "", 512, 0 }, // some floating point registers here. So, cpsr
     59   { "", 512, 0 }, // must be register 25.
     60   { "", 512, 0 },
     61   { "", 512, 0 },
     62   { "", 512, 0 },
     63   { "", 512, 0 },
     64   { "", 512, 0 },
     65   { "cpsr", 512, 32 },
     66   { "d0", 544, 64 },
     67   { "d1", 608, 64 },
     68   { "d2", 672, 64 },
     69   { "d3", 736, 64 },
     70   { "d4", 800, 64 },
     71   { "d5", 864, 64 },
     72   { "d6", 928, 64 },
     73   { "d7", 992, 64 },
     74   { "d8", 1056, 64 },
     75   { "d9", 1120, 64 },
     76   { "d10", 1184, 64 },
     77   { "d11", 1248, 64 },
     78   { "d12", 1312, 64 },
     79   { "d13", 1376, 64 },
     80   { "d14", 1440, 64 },
     81   { "d15", 1504, 64 },
     82   { "d16", 1568, 64 },
     83   { "d17", 1632, 64 },
     84   { "d18", 1696, 64 },
     85   { "d19", 1760, 64 },
     86   { "d20", 1824, 64 },
     87   { "d21", 1888, 64 },
     88   { "d22", 1952, 64 },
     89   { "d23", 2016, 64 },
     90   { "d24", 2080, 64 },
     91   { "d25", 2144, 64 },
     92   { "d26", 2208, 64 },
     93   { "d27", 2272, 64 },
     94   { "d28", 2336, 64 },
     95   { "d29", 2400, 64 },
     96   { "d30", 2464, 64 },
     97   { "d31", 2528, 64 },
     98   { "fpscr", 2592, 32 }
     99 };
    100 static const char *expedite_regs[] = { "r11", "sp", "pc", 0 };
    101 #define num_regs (sizeof (regs) / sizeof (regs[0]))
    102 
    103 static
    104 CORE_ADDR get_pc (void)
    105 {
    106    unsigned long pc;
    107 
    108    collect_register_by_name ("pc", &pc);
    109 
    110    dlog(1, "stop pc is %p\n", (void *) pc);
    111    return pc;
    112 }
    113 
    114 static
    115 void set_pc (CORE_ADDR newpc)
    116 {
    117    Bool mod;
    118    supply_register_by_name ("pc", &newpc, &mod);
    119    if (mod)
    120       dlog(1, "set pc to %p\n", C2v (newpc));
    121    else
    122       dlog(1, "set pc not changed %p\n", C2v (newpc));
    123 }
    124 
    125 Addr thumb_pc (Addr pc)
    126 {
    127    // If the thumb bit (bit 0) is already set, we trust it.
    128    if (pc & 1) {
    129       dlog (1, "%p = thumb (bit0 is set)\n", C2v (pc));
    130       return pc;
    131    }
    132 
    133    // Here, bit 0 is not set.
    134    // For a pc aligned on 4 bytes, we have to use the debug
    135    // info to determine the thumb-ness.
    136    // else (aligned on 2 bytes), we trust this is a thumb
    137    // address and we set the thumb bit.
    138 
    139    if (pc & 2) {
    140       dlog (1, "bit0 not set, bit1 set => %p = thumb\n", C2v (pc));
    141       return pc | 1;
    142    }
    143 
    144    // pc aligned on 4 bytes. We need to use debug info.
    145    {
    146       const HChar *fnname;
    147       SymAVMAs avmas;
    148       // If this is a thumb instruction, we need to ask
    149       // the debug info with the bit0 set
    150       // (why can't debug info do that for us ???)
    151       // (why if this is a 4 bytes thumb instruction ???)
    152       if (VG_(get_fnname_raw) (pc | 1, &fnname)) {
    153          if (VG_(lookup_symbol_SLOW)( "*", fnname, &avmas )) {
    154             dlog (1, "fnname %s lookupsym %p => %p %s.\n",
    155                   fnname, C2v(avmas.main), C2v(pc),
    156                   (avmas.main & 1 ? "thumb" : "arm"));
    157             if (avmas.main & 1)
    158                return pc | 1;
    159             else
    160                return pc;
    161 
    162          } else {
    163             dlog (1, "%p fnname %s lookupsym failed?. Assume arm\n",
    164                   C2v (pc), fnname);
    165             return pc;
    166          }
    167       } else {
    168          // Can't find function name. We assume this is arm
    169          dlog (1, "%p unknown fnname?. Assume arm\n", C2v (pc));
    170          return pc;
    171       }
    172    }
    173 }
    174 
    175 /* store registers in the guest state (gdbserver_to_valgrind)
    176    or fetch register from the guest state (valgrind_to_gdbserver). */
    177 static
    178 void transfer_register (ThreadId tid, int abs_regno, void * buf,
    179                         transfer_direction dir, int size, Bool *mod)
    180 {
    181    ThreadState* tst = VG_(get_ThreadState)(tid);
    182    int set = abs_regno / num_regs;
    183    int regno = abs_regno % num_regs;
    184    *mod = False;
    185 
    186    VexGuestARMState* arm = (VexGuestARMState*) get_arch (set, tst);
    187 
    188    switch (regno) {
    189    // numbers here have to match the order of regs above
    190    // Attention: gdb order does not match valgrind order.
    191    case 0:  VG_(transfer) (&arm->guest_R0,   buf, dir, size, mod); break;
    192    case 1:  VG_(transfer) (&arm->guest_R1,   buf, dir, size, mod); break;
    193    case 2:  VG_(transfer) (&arm->guest_R2,   buf, dir, size, mod); break;
    194    case 3:  VG_(transfer) (&arm->guest_R3,   buf, dir, size, mod); break;
    195    case 4:  VG_(transfer) (&arm->guest_R4,   buf, dir, size, mod); break;
    196    case 5:  VG_(transfer) (&arm->guest_R5,   buf, dir, size, mod); break;
    197    case 6:  VG_(transfer) (&arm->guest_R6,   buf, dir, size, mod); break;
    198    case 7:  VG_(transfer) (&arm->guest_R7,   buf, dir, size, mod); break;
    199    case 8:  VG_(transfer) (&arm->guest_R8,   buf, dir, size, mod); break;
    200    case 9:  VG_(transfer) (&arm->guest_R9,   buf, dir, size, mod); break;
    201    case 10: VG_(transfer) (&arm->guest_R10,  buf, dir, size, mod); break;
    202    case 11: VG_(transfer) (&arm->guest_R11,  buf, dir, size, mod); break;
    203    case 12: VG_(transfer) (&arm->guest_R12,  buf, dir, size, mod); break;
    204    case 13: VG_(transfer) (&arm->guest_R13,  buf, dir, size, mod); break;
    205    case 14: VG_(transfer) (&arm->guest_R14,  buf, dir, size, mod); break;
    206    case 15: {
    207       VG_(transfer) (&arm->guest_R15T, buf, dir, size, mod);
    208       if (dir == gdbserver_to_valgrind && *mod) {
    209          // If gdb is changing the PC, we have to set the thumb bit
    210          // if needed.
    211          arm->guest_R15T = thumb_pc(arm->guest_R15T);
    212       }
    213       break;
    214    }
    215    case 16:
    216    case 17:
    217    case 18:
    218    case 19:
    219    case 20: /* 9 "empty registers". See struct reg regs above. */
    220    case 21:
    221    case 22:
    222    case 23:
    223    case 24: *mod = False; break;
    224    case 25: {
    225       UInt cpsr = LibVEX_GuestARM_get_cpsr (arm);
    226       if (dir == valgrind_to_gdbserver) {
    227          VG_(transfer) (&cpsr, buf, dir, size, mod);
    228       } else {
    229 #      if 0
    230          UInt newcpsr;
    231          VG_(transfer) (&newcpsr, buf, dir, size, mod);
    232          *mod = newcpsr != cpsr;
    233          // GDBTD ???? see FIXME in guest_arm_helpers.c
    234          LibVEX_GuestARM_put_flags (newcpsr, arm);
    235 #      else
    236          *mod = False;
    237 #      endif
    238       }
    239       break;
    240    }
    241    case 26: VG_(transfer) (&arm->guest_D0,  buf, dir, size, mod); break;
    242    case 27: VG_(transfer) (&arm->guest_D1,  buf, dir, size, mod); break;
    243    case 28: VG_(transfer) (&arm->guest_D2,  buf, dir, size, mod); break;
    244    case 29: VG_(transfer) (&arm->guest_D3,  buf, dir, size, mod); break;
    245    case 30: VG_(transfer) (&arm->guest_D4,  buf, dir, size, mod); break;
    246    case 31: VG_(transfer) (&arm->guest_D5,  buf, dir, size, mod); break;
    247    case 32: VG_(transfer) (&arm->guest_D6,  buf, dir, size, mod); break;
    248    case 33: VG_(transfer) (&arm->guest_D7,  buf, dir, size, mod); break;
    249    case 34: VG_(transfer) (&arm->guest_D8,  buf, dir, size, mod); break;
    250    case 35: VG_(transfer) (&arm->guest_D9,  buf, dir, size, mod); break;
    251    case 36: VG_(transfer) (&arm->guest_D10, buf, dir, size, mod); break;
    252    case 37: VG_(transfer) (&arm->guest_D11, buf, dir, size, mod); break;
    253    case 38: VG_(transfer) (&arm->guest_D12, buf, dir, size, mod); break;
    254    case 39: VG_(transfer) (&arm->guest_D13, buf, dir, size, mod); break;
    255    case 40: VG_(transfer) (&arm->guest_D14, buf, dir, size, mod); break;
    256    case 41: VG_(transfer) (&arm->guest_D15, buf, dir, size, mod); break;
    257    case 42: VG_(transfer) (&arm->guest_D16, buf, dir, size, mod); break;
    258    case 43: VG_(transfer) (&arm->guest_D17, buf, dir, size, mod); break;
    259    case 44: VG_(transfer) (&arm->guest_D18, buf, dir, size, mod); break;
    260    case 45: VG_(transfer) (&arm->guest_D19, buf, dir, size, mod); break;
    261    case 46: VG_(transfer) (&arm->guest_D20, buf, dir, size, mod); break;
    262    case 47: VG_(transfer) (&arm->guest_D21, buf, dir, size, mod); break;
    263    case 48: VG_(transfer) (&arm->guest_D22, buf, dir, size, mod); break;
    264    case 49: VG_(transfer) (&arm->guest_D23, buf, dir, size, mod); break;
    265    case 50: VG_(transfer) (&arm->guest_D24, buf, dir, size, mod); break;
    266    case 51: VG_(transfer) (&arm->guest_D25, buf, dir, size, mod); break;
    267    case 52: VG_(transfer) (&arm->guest_D26, buf, dir, size, mod); break;
    268    case 53: VG_(transfer) (&arm->guest_D27, buf, dir, size, mod); break;
    269    case 54: VG_(transfer) (&arm->guest_D28, buf, dir, size, mod); break;
    270    case 55: VG_(transfer) (&arm->guest_D29, buf, dir, size, mod); break;
    271    case 56: VG_(transfer) (&arm->guest_D30, buf, dir, size, mod); break;
    272    case 57: VG_(transfer) (&arm->guest_D31, buf, dir, size, mod); break;
    273    case 58: VG_(transfer) (&arm->guest_FPSCR, buf, dir, size, mod); break;
    274    default: vg_assert(0);
    275    }
    276 }
    277 
    278 static
    279 const char* target_xml (Bool shadow_mode)
    280 {
    281    if (shadow_mode) {
    282       return "arm-with-vfpv3-valgrind.xml";
    283    } else {
    284       return "arm-with-vfpv3.xml";
    285    }
    286 }
    287 
    288 static CORE_ADDR** target_get_dtv (ThreadState *tst)
    289 {
    290    VexGuestARMState* arm = (VexGuestARMState*)&tst->arch.vex;
    291    // arm dtv is pointed to by TPIDRURO
    292    return (CORE_ADDR**)((CORE_ADDR)arm->guest_TPIDRURO);
    293 }
    294 
    295 static struct valgrind_target_ops low_target = {
    296    num_regs,
    297    regs,
    298    13, //SP
    299    transfer_register,
    300    get_pc,
    301    set_pc,
    302    "arm",
    303    target_xml,
    304    target_get_dtv
    305 };
    306 
    307 void arm_init_architecture (struct valgrind_target_ops *target)
    308 {
    309    *target = low_target;
    310    set_register_cache (regs, num_regs);
    311    gdbserver_expedite_regs = expedite_regs;
    312 }
    313