db_trace.c

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    1 /*-
    2  * Mach Operating System
    3  * Copyright (c) 1991,1990 Carnegie Mellon University
    4  * All Rights Reserved.
    5  *
    6  * Permission to use, copy, modify and distribute this software and its
    7  * documentation is hereby granted, provided that both the copyright
    8  * notice and this permission notice appear in all copies of the
    9  * software, derivative works or modified versions, and any portions
   10  * thereof, and that both notices appear in supporting documentation.
   11  *
   12  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
   13  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
   14  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   15  *
   16  * Carnegie Mellon requests users of this software to return to
   17  *
   18  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
   19  *  School of Computer Science
   20  *  Carnegie Mellon University
   21  *  Pittsburgh PA 15213-3890
   22  *
   23  * any improvements or extensions that they make and grant Carnegie the
   24  * rights to redistribute these changes.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD$");
   29 
   30 #include <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/kdb.h>
   33 #include <sys/proc.h>
   34 #include <sys/reg.h>
   35 #include <sys/smp.h>
   36 #include <sys/stack.h>
   37 
   38 #include <machine/cpu.h>
   39 #include <machine/md_var.h>
   40 #include <machine/pcb.h>
   41 #include <machine/stack.h>
   42 
   43 #include <vm/vm.h>
   44 #include <vm/vm_param.h>
   45 #include <vm/pmap.h>
   46 
   47 #include <ddb/ddb.h>
   48 #include <ddb/db_access.h>
   49 #include <ddb/db_sym.h>
   50 #include <ddb/db_variables.h>
   51 
   52 static db_varfcn_t db_frame;
   53 static db_varfcn_t db_frame_seg;
   54 
   55 CTASSERT(sizeof(struct dbreg) == sizeof(((struct pcpu *)NULL)->pc_dbreg));
   56 
   57 /*
   58  * Machine register set.
   59  */
   60 #define DB_OFFSET(x)    (db_expr_t *)offsetof(struct trapframe, x)
   61 struct db_variable db_regs[] = {
   62         { "cs",         DB_OFFSET(tf_cs),       db_frame_seg },
   63         { "ds",         DB_OFFSET(tf_ds),       db_frame_seg },
   64         { "es",         DB_OFFSET(tf_es),       db_frame_seg },
   65         { "fs",         DB_OFFSET(tf_fs),       db_frame_seg },
   66         { "gs",         DB_OFFSET(tf_gs),       db_frame_seg },
   67         { "ss",         DB_OFFSET(tf_ss),       db_frame_seg },
   68         { "rax",        DB_OFFSET(tf_rax),      db_frame },
   69         { "rcx",        DB_OFFSET(tf_rcx),      db_frame },
   70         { "rdx",        DB_OFFSET(tf_rdx),      db_frame },
   71         { "rbx",        DB_OFFSET(tf_rbx),      db_frame },
   72         { "rsp",        DB_OFFSET(tf_rsp),      db_frame },
   73         { "rbp",        DB_OFFSET(tf_rbp),      db_frame },
   74         { "rsi",        DB_OFFSET(tf_rsi),      db_frame },
   75         { "rdi",        DB_OFFSET(tf_rdi),      db_frame },
   76         { "r8",         DB_OFFSET(tf_r8),       db_frame },
   77         { "r9",         DB_OFFSET(tf_r9),       db_frame },
   78         { "r10",        DB_OFFSET(tf_r10),      db_frame },
   79         { "r11",        DB_OFFSET(tf_r11),      db_frame },
   80         { "r12",        DB_OFFSET(tf_r12),      db_frame },
   81         { "r13",        DB_OFFSET(tf_r13),      db_frame },
   82         { "r14",        DB_OFFSET(tf_r14),      db_frame },
   83         { "r15",        DB_OFFSET(tf_r15),      db_frame },
   84         { "rip",        DB_OFFSET(tf_rip),      db_frame },
   85         { "rflags",     DB_OFFSET(tf_rflags),   db_frame },
   86 };
   87 struct db_variable *db_eregs = db_regs + nitems(db_regs);
   88 
   89 static int
   90 db_frame_seg(struct db_variable *vp, db_expr_t *valuep, int op)
   91 {
   92         uint16_t *reg;
   93 
   94         if (kdb_frame == NULL)
   95                 return (0);
   96 
   97         reg = (uint16_t *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
   98         if (op == DB_VAR_GET)
   99                 *valuep = *reg;
  100         else
  101                 *reg = *valuep;
  102         return (1);
  103 }
  104 
  105 static int
  106 db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
  107 {
  108         long *reg;
  109 
  110         if (kdb_frame == NULL)
  111                 return (0);
  112 
  113         reg = (long *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
  114         if (op == DB_VAR_GET)
  115                 *valuep = *reg;
  116         else
  117                 *reg = *valuep;
  118         return (1);
  119 }
  120 
  121 #define NORMAL          0
  122 #define TRAP            1
  123 #define INTERRUPT       2
  124 #define SYSCALL         3
  125 
  126 static void db_nextframe(struct amd64_frame **, db_addr_t *, struct thread *);
  127 static void db_print_stack_entry(const char *, db_addr_t, void *);
  128 
  129 static void
  130 db_print_stack_entry(const char *name, db_addr_t callpc, void *frame)
  131 {
  132 
  133         db_printf("%s() at ", name != NULL ? name : "??");
  134         db_printsym(callpc, DB_STGY_PROC);
  135         if (frame != NULL)
  136                 db_printf("/frame 0x%lx", (register_t)frame);
  137         db_printf("\n");
  138 }
  139 
  140 /*
  141  * Figure out the next frame up in the call stack.
  142  */
  143 static void
  144 db_nextframe(struct amd64_frame **fp, db_addr_t *ip, struct thread *td)
  145 {
  146         struct trapframe *tf;
  147         int frame_type;
  148         long rip, rsp, rbp;
  149         db_expr_t offset;
  150         c_db_sym_t sym;
  151         const char *name;
  152 
  153         rip = db_get_value((long) &(*fp)->f_retaddr, 8, FALSE);
  154         rbp = db_get_value((long) &(*fp)->f_frame, 8, FALSE);
  155 
  156         /*
  157          * Figure out frame type.  We look at the address just before
  158          * the saved instruction pointer as the saved EIP is after the
  159          * call function, and if the function being called is marked as
  160          * dead (such as panic() at the end of dblfault_handler()), then
  161          * the instruction at the saved EIP will be part of a different
  162          * function (syscall() in this example) rather than the one that
  163          * actually made the call.
  164          */
  165         frame_type = NORMAL;
  166         sym = db_search_symbol(rip - 1, DB_STGY_ANY, &offset);
  167         db_symbol_values(sym, &name, NULL);
  168         if (name != NULL) {
  169                 if (strcmp(name, "calltrap") == 0 ||
  170                     strcmp(name, "fork_trampoline") == 0 ||
  171                     strcmp(name, "mchk_calltrap") == 0 ||
  172                     strcmp(name, "nmi_calltrap") == 0 ||
  173                     strcmp(name, "Xdblfault") == 0)
  174                         frame_type = TRAP;
  175                 else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
  176                     strncmp(name, "Xapic_isr", 9) == 0 ||
  177                     strcmp(name, "Xxen_intr_upcall") == 0 ||
  178                     strcmp(name, "Xtimerint") == 0 ||
  179                     strcmp(name, "Xipi_intr_bitmap_handler") == 0 ||
  180                     strcmp(name, "Xcpustop") == 0 ||
  181                     strcmp(name, "Xcpususpend") == 0 ||
  182                     strcmp(name, "Xrendezvous") == 0)
  183                         frame_type = INTERRUPT;
  184                 else if (strcmp(name, "Xfast_syscall") == 0 ||
  185                     strcmp(name, "Xfast_syscall_pti") == 0 ||
  186                     strcmp(name, "fast_syscall_common") == 0)
  187                         frame_type = SYSCALL;
  188 #ifdef COMPAT_FREEBSD32
  189                 else if (strcmp(name, "Xint0x80_syscall") == 0)
  190                         frame_type = SYSCALL;
  191 #endif
  192         }
  193 
  194         /*
  195          * Normal frames need no special processing.
  196          */
  197         if (frame_type == NORMAL) {
  198                 *ip = (db_addr_t) rip;
  199                 *fp = (struct amd64_frame *) rbp;
  200                 return;
  201         }
  202 
  203         db_print_stack_entry(name, rip, &(*fp)->f_frame);
  204 
  205         /*
  206          * Point to base of trapframe which is just above the
  207          * current frame.
  208          */
  209         tf = (struct trapframe *)((long)*fp + 16);
  210 
  211         if (INKERNEL((long) tf)) {
  212                 rsp = tf->tf_rsp;
  213                 rip = tf->tf_rip;
  214                 rbp = tf->tf_rbp;
  215                 switch (frame_type) {
  216                 case TRAP:
  217                         db_printf("--- trap %#r", tf->tf_trapno);
  218                         break;
  219                 case SYSCALL:
  220                         db_printf("--- syscall");
  221                         db_decode_syscall(td, tf->tf_rax);
  222                         break;
  223                 case INTERRUPT:
  224                         db_printf("--- interrupt");
  225                         break;
  226                 default:
  227                         panic("The moon has moved again.");
  228                 }
  229                 db_printf(", rip = %#lr, rsp = %#lr, rbp = %#lr ---\n", rip,
  230                     rsp, rbp);
  231         }
  232 
  233         *ip = (db_addr_t) rip;
  234         *fp = (struct amd64_frame *) rbp;
  235 }
  236 
  237 static int __nosanitizeaddress __nosanitizememory
  238 db_backtrace(struct thread *td, struct trapframe *tf, struct amd64_frame *frame,
  239     db_addr_t pc, register_t sp, int count)
  240 {
  241         struct amd64_frame *actframe;
  242         const char *name;
  243         db_expr_t offset;
  244         c_db_sym_t sym;
  245         boolean_t first;
  246 
  247         if (count == -1)
  248                 count = 1024;
  249 
  250         first = TRUE;
  251         while (count-- && !db_pager_quit) {
  252                 sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
  253                 db_symbol_values(sym, &name, NULL);
  254 
  255                 /*
  256                  * Attempt to determine a (possibly fake) frame that gives
  257                  * the caller's pc.  It may differ from `frame' if the
  258                  * current function never sets up a standard frame or hasn't
  259                  * set one up yet or has just discarded one.  The last two
  260                  * cases can be guessed fairly reliably for code generated
  261                  * by gcc.  The first case is too much trouble to handle in
  262                  * general because the amount of junk on the stack depends
  263                  * on the pc (the special handling of "calltrap", etc. in
  264                  * db_nextframe() works because the `next' pc is special).
  265                  */
  266                 actframe = frame;
  267                 if (first) {
  268                         first = FALSE;
  269                         if (sym == C_DB_SYM_NULL && sp != 0) {
  270                                 /*
  271                                  * If a symbol couldn't be found, we've probably
  272                                  * jumped to a bogus location, so try and use
  273                                  * the return address to find our caller.
  274                                  */
  275                                 db_print_stack_entry(name, pc, NULL);
  276                                 pc = db_get_value(sp, 8, FALSE);
  277                                 if (db_search_symbol(pc, DB_STGY_PROC,
  278                                     &offset) == C_DB_SYM_NULL)
  279                                         break;
  280                                 continue;
  281                         } else if (tf != NULL) {
  282                                 int instr;
  283 
  284                                 instr = db_get_value(pc, 4, FALSE);
  285                                 if ((instr & 0xffffffff) == 0xe5894855) {
  286                                         /* pushq %rbp; movq %rsp, %rbp */
  287                                         actframe = (void *)(tf->tf_rsp - 8);
  288                                 } else if ((instr & 0xffffff) == 0xe58948) {
  289                                         /* movq %rsp, %rbp */
  290                                         actframe = (void *)tf->tf_rsp;
  291                                         if (tf->tf_rbp == 0) {
  292                                                 /* Fake frame better. */
  293                                                 frame = actframe;
  294                                         }
  295                                 } else if ((instr & 0xff) == 0xc3) {
  296                                         /* ret */
  297                                         actframe = (void *)(tf->tf_rsp - 8);
  298                                 } else if (offset == 0) {
  299                                         /* Probably an assembler symbol. */
  300                                         actframe = (void *)(tf->tf_rsp - 8);
  301                                 }
  302                         } else if (name != NULL &&
  303                             strcmp(name, "fork_trampoline") == 0) {
  304                                 /*
  305                                  * Don't try to walk back on a stack for a
  306                                  * process that hasn't actually been run yet.
  307                                  */
  308                                 db_print_stack_entry(name, pc, actframe);
  309                                 break;
  310                         }
  311                 }
  312 
  313                 db_print_stack_entry(name, pc, actframe);
  314 
  315                 if (actframe != frame) {
  316                         /* `frame' belongs to caller. */
  317                         pc = (db_addr_t)
  318                             db_get_value((long)&actframe->f_retaddr, 8, FALSE);
  319                         continue;
  320                 }
  321 
  322                 db_nextframe(&frame, &pc, td);
  323 
  324                 if (INKERNEL((long)pc) && !INKERNEL((long)frame)) {
  325                         sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
  326                         db_symbol_values(sym, &name, NULL);
  327                         db_print_stack_entry(name, pc, frame);
  328                         break;
  329                 }
  330                 if (!INKERNEL((long) frame)) {
  331                         break;
  332                 }
  333         }
  334 
  335         return (0);
  336 }
  337 
  338 void
  339 db_trace_self(void)
  340 {
  341         struct amd64_frame *frame;
  342         db_addr_t callpc;
  343         register_t rbp;
  344 
  345         __asm __volatile("movq %%rbp,%0" : "=r" (rbp));
  346         frame = (struct amd64_frame *)rbp;
  347         callpc = (db_addr_t)db_get_value((long)&frame->f_retaddr, 8, FALSE);
  348         frame = frame->f_frame;
  349         db_backtrace(curthread, NULL, frame, callpc, 0, -1);
  350 }
  351 
  352 int
  353 db_trace_thread(struct thread *thr, int count)
  354 {
  355         struct pcb *ctx;
  356         struct trapframe *tf;
  357 
  358         ctx = kdb_thr_ctx(thr);
  359         tf = thr == kdb_thread ? kdb_frame : NULL;
  360         return (db_backtrace(thr, tf, (struct amd64_frame *)ctx->pcb_rbp,
  361             ctx->pcb_rip, ctx->pcb_rsp, count));
  362 }
  363 
  364 void
  365 db_md_list_watchpoints(void)
  366 {
  367 
  368         dbreg_list_watchpoints();
  369 }
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FreeBSD/Linux Kernel Cross Reference sys/amd64/amd64/db_trace.c

FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/db_trace.c
