gnu/usr.bin/gdb/kgdb/trgt_i386.c

   1 /*
   2  * Copyright (c) 2004 Marcel Moolenaar
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/gnu/usr.bin/gdb/kgdb/trgt_i386.c,v 1.5 2005/09/11 05:36:30 marcel Exp $
  27  * $DragonFly: src/gnu/usr.bin/gdb/kgdb/trgt_i386.c,v 1.5 2008/01/14 21:36:38 corecode Exp $
  28  */
  29
  30 #include <sys/cdefs.h>
  31
  32 #include <sys/types.h>
  33 #include <machine/thread.h>
  34 #include <sys/thread.h>
  35 #include <machine/pcb.h>
  36 #include <machine/frame.h>
  37 #include <err.h>
  38 #include <kvm.h>
  39 #include <string.h>
  40
  41 #include <defs.h>
  42 #include <target.h>
  43 #include <gdbthread.h>
  44 #include <inferior.h>
  45 #include <regcache.h>
  46 #include <frame-unwind.h>
  47 #include <i386-tdep.h>
  48
  49 #include "kgdb.h"
  50
  51 void
  52 kgdb_trgt_fetch_registers(struct regcache *regcache, int regno)
  53 {
  54         struct kthr *kt;
  55         struct pcb pcb;
  56
  57         kt = kgdb_thr_lookup_tid(ptid_get_tid(inferior_ptid));
  58         if (kt == NULL) {
  59                 regcache_raw_supply(regcache, regno, NULL);
  60                 return;
  61         }
  62
  63         /*
  64          * kt->pcb == NULL is a marker for "non-dumping kernel thread".
  65          */
  66         if (kt->pcb == NULL) {
  67                 uintptr_t regs[5];
  68                 uintptr_t addr;
  69                 uintptr_t sp;
  70
  71                 addr = kt->kaddr + offsetof(struct thread, td_sp);
  72                 kvm_read(kvm, addr, &sp, sizeof(sp));
  73                 /*
  74                  * Stack is:
  75                  * -2 ret
  76                  * -1 popfl
  77                  * 0 popl %edi
  78                  * 1 popl %esi
  79                  * 2 popl %ebx
  80                  * 3 popl %ebp
  81                  * 4 ret
  82                  */
  83                 if (kvm_read(kvm, sp + 2 * sizeof(regs[0]), regs, sizeof(regs)) != sizeof(regs)) {
  84                         warnx("kvm_read: %s", kvm_geterr(kvm));
  85                         memset(regs, 0, sizeof(regs));
  86                 }
  87                 regcache_raw_supply(regcache, I386_EDI_REGNUM, &regs[0]);
  88                 regcache_raw_supply(regcache, I386_ESI_REGNUM, &regs[1]);
  89                 regcache_raw_supply(regcache, I386_EBX_REGNUM, &regs[2]);
  90                 regcache_raw_supply(regcache, I386_EBP_REGNUM, &regs[3]);
  91                 regcache_raw_supply(regcache, I386_EIP_REGNUM, &regs[4]);
  92                 sp += 7 * sizeof(regs[0]);
  93                 regcache_raw_supply(regcache, I386_ESP_REGNUM, &sp);
  94                 return;
  95         }
  96
  97         if (kvm_read(kvm, kt->pcb, &pcb, sizeof(pcb)) != sizeof(pcb)) {
  98                 warnx("kvm_read: %s", kvm_geterr(kvm));
  99                 memset(&pcb, 0, sizeof(pcb));
 100         }
 101         regcache_raw_supply(regcache, I386_EBX_REGNUM, (char *)&pcb.pcb_ebx);
 102         regcache_raw_supply(regcache, I386_ESP_REGNUM, (char *)&pcb.pcb_esp);
 103         regcache_raw_supply(regcache, I386_EBP_REGNUM, (char *)&pcb.pcb_ebp);
 104         regcache_raw_supply(regcache, I386_ESI_REGNUM, (char *)&pcb.pcb_esi);
 105         regcache_raw_supply(regcache, I386_EDI_REGNUM, (char *)&pcb.pcb_edi);
 106         regcache_raw_supply(regcache, I386_EIP_REGNUM, (char *)&pcb.pcb_eip);
 107 }
 108
 109 void
 110 kgdb_trgt_store_registers(struct regcache *regcache, int regno __unused)
 111 {
 112         fprintf_unfiltered(gdb_stderr, "XXX: %s\n", __func__);
 113 }
 114
 115 struct kgdb_frame_cache {
 116         int             intrframe;
 117         CORE_ADDR       pc;
 118         CORE_ADDR       sp;
 119 };
 120
 121 static int kgdb_trgt_frame_offset[15] = {
 122         offsetof(struct trapframe, tf_eax),
 123         offsetof(struct trapframe, tf_ecx),
 124         offsetof(struct trapframe, tf_edx),
 125         offsetof(struct trapframe, tf_ebx),
 126         offsetof(struct trapframe, tf_esp),
 127         offsetof(struct trapframe, tf_ebp),
 128         offsetof(struct trapframe, tf_esi),
 129         offsetof(struct trapframe, tf_edi),
 130         offsetof(struct trapframe, tf_eip),
 131         offsetof(struct trapframe, tf_eflags),
 132         offsetof(struct trapframe, tf_cs),
 133         offsetof(struct trapframe, tf_ss),
 134         offsetof(struct trapframe, tf_ds),
 135         offsetof(struct trapframe, tf_es),
 136         offsetof(struct trapframe, tf_fs)
 137 };
 138
 139 static struct kgdb_frame_cache *
 140 kgdb_trgt_frame_cache(struct frame_info *next_frame, void **this_cache)
 141 {
 142         char buf[MAX_REGISTER_SIZE];
 143         struct kgdb_frame_cache *cache;
 144         char *pname;
 145
 146         cache = *this_cache;
 147         if (cache == NULL) {
 148                 cache = FRAME_OBSTACK_ZALLOC(struct kgdb_frame_cache);
 149                 *this_cache = cache;
 150                 cache->pc = get_frame_address_in_block(next_frame);
 151                 find_pc_partial_function(cache->pc, &pname, NULL, NULL);
 152
 153                 /*
 154                  * Handle weird trapframe cases:
 155                  *
 156                  * 4 for pushed esp (IN the function!)
 157                  * + 8 for cpl/intno (IN the function, only intrs)
 158                  */
 159                 cache->intrframe = 4;
 160                 if (pname[0] == 'X')
 161                         cache->intrframe += offsetof(struct intrframe, if_esp) -
 162                                             offsetof(struct trapframe, tf_esp);
 163
 164                 frame_unwind_register(next_frame, I386_ESP_REGNUM, buf);
 165                 cache->sp = extract_unsigned_integer(buf,
 166                     register_size(current_gdbarch, I386_ESP_REGNUM));
 167         }
 168         return (cache);
 169 }
 170
 171 static void
 172 kgdb_trgt_trapframe_this_id(struct frame_info *next_frame, void **this_cache,
 173     struct frame_id *this_id)
 174 {
 175         struct kgdb_frame_cache *cache;
 176
 177         cache = kgdb_trgt_frame_cache(next_frame, this_cache);
 178         *this_id = frame_id_build(cache->sp, cache->pc);
 179 }
 180
 181 static void
 182 kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
 183     void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
 184     CORE_ADDR *addrp, int *realnump, gdb_byte *valuep)
 185 {
 186         char dummy_valuep[MAX_REGISTER_SIZE];
 187         struct kgdb_frame_cache *cache;
 188         int ofs, regsz;
 189
 190         regsz = register_size(current_gdbarch, regnum);
 191
 192         if (valuep == NULL)
 193                 valuep = dummy_valuep;
 194         memset(valuep, 0, regsz);
 195         *optimizedp = 0;
 196         *addrp = 0;
 197         *lvalp = not_lval;
 198         *realnump = -1;
 199
 200         if (regnum < I386_EAX_REGNUM || regnum > I386_FS_REGNUM)
 201                 return;
 202
 203         cache = kgdb_trgt_frame_cache(next_frame, this_cache);
 204
 205         ofs = kgdb_trgt_frame_offset[regnum];
 206         *addrp = cache->sp + ofs + cache->intrframe;
 207
 208         /*
 209          * If we are in the kernel, we don't have esp stored in the
 210          * trapframe, but we can calculate it simply by subtracting
 211          * the size of the frame.
 212          */
 213         if (regnum == I386_ESP_REGNUM) {
 214                 char buf[4];
 215
 216                 frame_unwind_register(next_frame, I386_CS_REGNUM, buf);
 217                 if (extract_unsigned_integer(buf, 4) != SEL_UPL) {
 218                         store_unsigned_integer(valuep, regsz, *addrp);
 219                         return;
 220                 }
 221                 /* FALLTHROUGH */
 222         }
 223         *lvalp = lval_memory;
 224         target_read_memory(*addrp, valuep, regsz);
 225 }
 226
 227 static int
 228 kgdb_trgt_trapframe_sniffer(const struct frame_unwind *self,
 229                             struct frame_info *next_frame,
 230                             void **this_prologue_cache)
 231 {
 232         char *pname;
 233         CORE_ADDR pc;
 234
 235         pc = frame_unwind_address_in_block(next_frame, NORMAL_FRAME);
 236         pname = NULL;
 237         find_pc_partial_function(pc, &pname, NULL, NULL);
 238         if (pname == NULL)
 239                 return (NULL);
 240         if (strcmp(pname, "calltrap") == 0 ||
 241             strcmp(pname, "dblfault_handler") == 0 ||
 242             (pname[0] == 'X' && pname[1] != '_'))
 243                 return 1;
 244         /* printf("%s: %llx =%s\n", __func__, pc, pname); */
 245         return 0;
 246 }
 247
 248 const struct frame_unwind kgdb_trgt_trapframe_unwind = {
 249         NORMAL_FRAME,
 250         &kgdb_trgt_trapframe_this_id,
 251         &kgdb_trgt_trapframe_prev_register,
 252         .sniffer = kgdb_trgt_trapframe_sniffer
 253 };