db_watch.c

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    1 /*-
    2  * SPDX-License-Identifier: MIT-CMU
    3  *
    4  * Mach Operating System
    5  * Copyright (c) 1991,1990 Carnegie Mellon University
    6  * All Rights Reserved.
    7  *
    8  * Permission to use, copy, modify and distribute this software and its
    9  * documentation is hereby granted, provided that both the copyright
   10  * notice and this permission notice appear in all copies of the
   11  * software, derivative works or modified versions, and any portions
   12  * thereof, and that both notices appear in supporting documentation.
   13  *
   14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
   15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
   16  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   17  *
   18  * Carnegie Mellon requests users of this software to return to
   19  *
   20  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
   21  *  School of Computer Science
   22  *  Carnegie Mellon University
   23  *  Pittsburgh PA 15213-3890
   24  *
   25  * any improvements or extensions that they make and grant Carnegie the
   26  * rights to redistribute these changes.
   27  */
   28 /*
   29  *      Author: Richard P. Draves, Carnegie Mellon University
   30  *      Date:   10/90
   31  */
   32 
   33 #include <sys/cdefs.h>
   34 __FBSDID("$FreeBSD$");
   35 
   36 #include <sys/param.h>
   37 #include <sys/kdb.h>
   38 #include <sys/kernel.h>
   39 #include <sys/lock.h>
   40 #include <sys/proc.h>
   41 
   42 #include <vm/vm.h>
   43 #include <vm/pmap.h>
   44 #include <vm/vm_map.h>
   45 
   46 #include <machine/kdb.h>
   47 
   48 #include <ddb/ddb.h>
   49 #include <ddb/db_watch.h>
   50 
   51 /*
   52  * Watchpoints.
   53  */
   54 
   55 static bool             db_watchpoints_inserted = true;
   56 
   57 #define NWATCHPOINTS    100
   58 static struct db_watchpoint     db_watch_table[NWATCHPOINTS];
   59 static db_watchpoint_t  db_next_free_watchpoint = &db_watch_table[0];
   60 static db_watchpoint_t  db_free_watchpoints = 0;
   61 static db_watchpoint_t  db_watchpoint_list = 0;
   62 
   63 static db_watchpoint_t  db_watchpoint_alloc(void);
   64 static void             db_watchpoint_free(db_watchpoint_t watch);
   65 static void             db_delete_watchpoint(vm_map_t map, db_addr_t addr);
   66 #ifdef notused
   67 static bool             db_find_watchpoint(vm_map_t map, db_addr_t addr,
   68                                         db_regs_t *regs);
   69 #endif
   70 static void             db_list_watchpoints(void);
   71 static void             db_set_watchpoint(vm_map_t map, db_addr_t addr,
   72                                        vm_size_t size);
   73 
   74 static db_watchpoint_t
   75 db_watchpoint_alloc(void)
   76 {
   77         db_watchpoint_t watch;
   78 
   79         if ((watch = db_free_watchpoints) != 0) {
   80             db_free_watchpoints = watch->link;
   81             return (watch);
   82         }
   83         if (db_next_free_watchpoint == &db_watch_table[NWATCHPOINTS]) {
   84             db_printf("All watchpoints used.\n");
   85             return (0);
   86         }
   87         watch = db_next_free_watchpoint;
   88         db_next_free_watchpoint++;
   89 
   90         return (watch);
   91 }
   92 
   93 static void
   94 db_watchpoint_free(db_watchpoint_t watch)
   95 {
   96         watch->link = db_free_watchpoints;
   97         db_free_watchpoints = watch;
   98 }
   99 
  100 static void
  101 db_set_watchpoint(vm_map_t map, db_addr_t addr, vm_size_t size)
  102 {
  103         db_watchpoint_t watch;
  104 
  105         if (map == NULL) {
  106             db_printf("No map.\n");
  107             return;
  108         }
  109 
  110         /*
  111          *      Should we do anything fancy with overlapping regions?
  112          */
  113 
  114         for (watch = db_watchpoint_list;
  115              watch != 0;
  116              watch = watch->link)
  117             if (db_map_equal(watch->map, map) &&
  118                 (watch->loaddr == addr) &&
  119                 (watch->hiaddr == addr+size)) {
  120                 db_printf("Already set.\n");
  121                 return;
  122             }
  123 
  124         watch = db_watchpoint_alloc();
  125         if (watch == 0) {
  126             db_printf("Too many watchpoints.\n");
  127             return;
  128         }
  129 
  130         watch->map = map;
  131         watch->loaddr = addr;
  132         watch->hiaddr = addr+size;
  133 
  134         watch->link = db_watchpoint_list;
  135         db_watchpoint_list = watch;
  136 
  137         db_watchpoints_inserted = false;
  138 }
  139 
  140 static void
  141 db_delete_watchpoint(vm_map_t map, db_addr_t addr)
  142 {
  143         db_watchpoint_t watch;
  144         db_watchpoint_t *prev;
  145 
  146         for (prev = &db_watchpoint_list;
  147              (watch = *prev) != 0;
  148              prev = &watch->link)
  149             if (db_map_equal(watch->map, map) &&
  150                 (watch->loaddr <= addr) &&
  151                 (addr < watch->hiaddr)) {
  152                 *prev = watch->link;
  153                 db_watchpoint_free(watch);
  154                 return;
  155             }
  156 
  157         db_printf("Not set.\n");
  158 }
  159 
  160 static void
  161 db_list_watchpoints(void)
  162 {
  163         db_watchpoint_t watch;
  164 
  165         if (db_watchpoint_list == 0) {
  166             db_printf("No watchpoints set\n");
  167             return;
  168         }
  169 
  170 #ifdef __LP64__
  171         db_printf(" Map                Address          Size\n");
  172 #else
  173         db_printf(" Map        Address  Size\n");
  174 #endif
  175         for (watch = db_watchpoint_list;
  176              watch != 0;
  177              watch = watch->link)
  178 #ifdef __LP64__
  179             db_printf("%s%16p  %16lx  %lx\n",
  180 #else
  181             db_printf("%s%8p  %8lx  %lx\n",
  182 #endif
  183                       db_map_current(watch->map) ? "*" : " ",
  184                       (void *)watch->map, (long)watch->loaddr,
  185                       (long)watch->hiaddr - (long)watch->loaddr);
  186 }
  187 
  188 /* Delete watchpoint */
  189 /*ARGSUSED*/
  190 void
  191 db_deletewatch_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
  192    char *modif)
  193 {
  194         db_delete_watchpoint(db_map_addr(addr), addr);
  195 }
  196 
  197 /* Set watchpoint */
  198 /*ARGSUSED*/
  199 void
  200 db_watchpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
  201    char *modif)
  202 {
  203         vm_size_t       size;
  204         db_expr_t       value;
  205 
  206         if (db_expression(&value))
  207             size = (vm_size_t) value;
  208         else
  209             size = 4;
  210         db_skip_to_eol();
  211 
  212         db_set_watchpoint(db_map_addr(addr), addr, size);
  213 }
  214 
  215 /*
  216  * At least one non-optional show-command must be implemented using
  217  * DB_SHOW_COMMAND() so that db_show_cmd_set gets created.  Here is one.
  218  */
  219 DB_SHOW_COMMAND_FLAGS(watches, db_listwatch_cmd, DB_CMD_MEMSAFE)
  220 {
  221         db_list_watchpoints();
  222         db_md_list_watchpoints();
  223 }
  224 
  225 void
  226 db_set_watchpoints(void)
  227 {
  228         db_watchpoint_t watch;
  229 
  230         if (!db_watchpoints_inserted) {
  231             for (watch = db_watchpoint_list;
  232                  watch != 0;
  233                  watch = watch->link)
  234                 pmap_protect(watch->map->pmap,
  235                              trunc_page(watch->loaddr),
  236                              round_page(watch->hiaddr),
  237                              VM_PROT_READ);
  238 
  239             db_watchpoints_inserted = true;
  240         }
  241 }
  242 
  243 void
  244 db_clear_watchpoints(void)
  245 {
  246         db_watchpoints_inserted = false;
  247 }
  248 
  249 #ifdef notused
  250 static bool
  251 db_find_watchpoint(vm_map_t map, db_addr_t addr, db_regs_t regs)
  252 {
  253         db_watchpoint_t watch;
  254         db_watchpoint_t found = 0;
  255 
  256         for (watch = db_watchpoint_list;
  257              watch != 0;
  258              watch = watch->link)
  259             if (db_map_equal(watch->map, map)) {
  260                 if ((watch->loaddr <= addr) &&
  261                     (addr < watch->hiaddr))
  262                     return (true);
  263                 else if ((trunc_page(watch->loaddr) <= addr) &&
  264                          (addr < round_page(watch->hiaddr)))
  265                     found = watch;
  266             }
  267 
  268         /*
  269          *      We didn't hit exactly on a watchpoint, but we are
  270          *      in a protected region.  We want to single-step
  271          *      and then re-protect.
  272          */
  273 
  274         if (found) {
  275             db_watchpoints_inserted = false;
  276             db_single_step(regs);
  277         }
  278 
  279         return (false);
  280 }
  281 #endif
  282 
  283 /* Delete hardware watchpoint */
  284 void
  285 db_deletehwatch_cmd(db_expr_t addr, bool have_addr, db_expr_t size,
  286    char *modif)
  287 {
  288         int rc;
  289 
  290         if (size < 0)
  291                 size = 4;
  292 
  293         rc = kdb_cpu_clr_watchpoint((vm_offset_t)addr, (vm_size_t)size);
  294         switch (rc) {
  295         case ENXIO:
  296                 /* Not supported, ignored. */
  297                 break;
  298         case EINVAL:
  299                 db_printf("Invalid watchpoint address or size.\n");
  300                 break;
  301         default:
  302                 if (rc != 0)
  303                         db_printf("Hardware watchpoint could not be deleted, "
  304                             "status=%d\n", rc);
  305                 break;
  306         }
  307 }
  308 
  309 /* Set hardware watchpoint */
  310 void
  311 db_hwatchpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t size,
  312    char *modif)
  313 {
  314         int rc;
  315 
  316         if (size < 0)
  317                 size = 4;
  318 
  319         rc = kdb_cpu_set_watchpoint((vm_offset_t)addr, (vm_size_t)size,
  320             KDB_DBG_ACCESS_W);
  321 
  322         switch (rc) {
  323         case EINVAL:
  324                 db_printf("Invalid watchpoint size or address.\n");
  325                 break;
  326         case EBUSY:
  327                 db_printf("No hardware watchpoints available.\n");
  328                 break;
  329         case ENXIO:
  330                 db_printf("Hardware watchpoints are not supported on this platform.\n");
  331                 break;
  332         default:
  333                 if (rc != 0)
  334                         db_printf("Could not set hardware watchpoint, "
  335                             "status=%d\n", rc);
  336         }
  337 }
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FreeBSD/Linux Kernel Cross Reference sys/ddb/db_watch.c

FreeBSD/Linux Kernel Cross Reference
sys/ddb/db_watch.c
