dtrace_subr.c

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    1 /*
    2  * CDDL HEADER START
    3  *
    4  * The contents of this file are subject to the terms of the
    5  * Common Development and Distribution License, Version 1.0 only
    6  * (the "License").  You may not use this file except in compliance
    7  * with the License.
    8  *
    9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   10  * or http://www.opensolaris.org/os/licensing.
   11  * See the License for the specific language governing permissions
   12  * and limitations under the License.
   13  *
   14  * When distributing Covered Code, include this CDDL HEADER in each
   15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
   16  * If applicable, add the following below this CDDL HEADER, with the
   17  * fields enclosed by brackets "[]" replaced with your own identifying
   18  * information: Portions Copyright [yyyy] [name of copyright owner]
   19  *
   20  * CDDL HEADER END
   21  *
   22  * $FreeBSD$
   23  *
   24  */
   25 /*
   26  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
   27  * Use is subject to license terms.
   28  */
   29 
   30 #include <sys/param.h>
   31 #include <sys/systm.h>
   32 #include <sys/kernel.h>
   33 #include <sys/malloc.h>
   34 #include <sys/kmem.h>
   35 #include <sys/proc.h>
   36 #include <sys/smp.h>
   37 #include <sys/dtrace_impl.h>
   38 #include <sys/dtrace_bsd.h>
   39 #include <cddl/dev/dtrace/dtrace_cddl.h>
   40 #include <machine/armreg.h>
   41 #include <machine/clock.h>
   42 #include <machine/frame.h>
   43 #include <machine/trap.h>
   44 #include <vm/pmap.h>
   45 
   46 #define DELAYBRANCH(x)  ((int)(x) < 0)
   47 
   48 #define BIT_PC          15
   49 #define BIT_LR          14
   50 #define BIT_SP          13
   51 
   52 extern dtrace_id_t      dtrace_probeid_error;
   53 extern int (*dtrace_invop_jump_addr)(struct trapframe *);
   54 extern void dtrace_getnanotime(struct timespec *tsp);
   55 extern void dtrace_getnanouptime(struct timespec *tsp);
   56 
   57 int dtrace_invop(uintptr_t, struct trapframe *, uintptr_t);
   58 void dtrace_invop_init(void);
   59 void dtrace_invop_uninit(void);
   60 
   61 typedef struct dtrace_invop_hdlr {
   62         int (*dtih_func)(uintptr_t, struct trapframe *, uintptr_t);
   63         struct dtrace_invop_hdlr *dtih_next;
   64 } dtrace_invop_hdlr_t;
   65 
   66 dtrace_invop_hdlr_t *dtrace_invop_hdlr;
   67 
   68 int
   69 dtrace_invop(uintptr_t addr, struct trapframe *frame, uintptr_t eax)
   70 {
   71         struct thread *td;
   72         dtrace_invop_hdlr_t *hdlr;
   73         int rval;
   74 
   75         rval = 0;
   76         td = curthread;
   77         td->t_dtrace_trapframe = frame;
   78         for (hdlr = dtrace_invop_hdlr; hdlr != NULL; hdlr = hdlr->dtih_next)
   79                 if ((rval = hdlr->dtih_func(addr, frame, eax)) != 0)
   80                         break;
   81         td->t_dtrace_trapframe = NULL;
   82         return (rval);
   83 }
   84 
   85 
   86 void
   87 dtrace_invop_add(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
   88 {
   89         dtrace_invop_hdlr_t *hdlr;
   90 
   91         hdlr = kmem_alloc(sizeof (dtrace_invop_hdlr_t), KM_SLEEP);
   92         hdlr->dtih_func = func;
   93         hdlr->dtih_next = dtrace_invop_hdlr;
   94         dtrace_invop_hdlr = hdlr;
   95 }
   96 
   97 void
   98 dtrace_invop_remove(int (*func)(uintptr_t, struct trapframe *, uintptr_t))
   99 {
  100         dtrace_invop_hdlr_t *hdlr = dtrace_invop_hdlr, *prev = NULL;
  101 
  102         for (;;) {
  103                 if (hdlr == NULL)
  104                         panic("attempt to remove non-existent invop handler");
  105 
  106                 if (hdlr->dtih_func == func)
  107                         break;
  108 
  109                 prev = hdlr;
  110                 hdlr = hdlr->dtih_next;
  111         }
  112 
  113         if (prev == NULL) {
  114                 ASSERT(dtrace_invop_hdlr == hdlr);
  115                 dtrace_invop_hdlr = hdlr->dtih_next;
  116         } else {
  117                 ASSERT(dtrace_invop_hdlr != hdlr);
  118                 prev->dtih_next = hdlr->dtih_next;
  119         }
  120 
  121         kmem_free(hdlr, 0);
  122 }
  123 
  124 
  125 /*ARGSUSED*/
  126 void
  127 dtrace_toxic_ranges(void (*func)(uintptr_t base, uintptr_t limit))
  128 {
  129 
  130         /*
  131          * There are no ranges to exclude that are common to all 32-bit arm
  132          * platforms.  This function only needs to exclude ranges "... in
  133          * which it is impossible to recover from such a load after it has been
  134          * attempted." -- i.e., accessing within the range causes some sort
  135          * fault in the system which is not handled by the normal arm
  136          * exception-handling mechanisms.  If systems exist where that is the
  137          * case, a method to handle this functionality would have to be added to
  138          * the platform_if interface so that those systems could provide their
  139          * specific toxic range(s).
  140          */
  141 }
  142 
  143 void
  144 dtrace_xcall(processorid_t cpu, dtrace_xcall_t func, void *arg)
  145 {
  146         cpuset_t cpus;
  147 
  148         if (cpu == DTRACE_CPUALL)
  149                 cpus = all_cpus;
  150         else
  151                 CPU_SETOF(cpu, &cpus);
  152 
  153         smp_rendezvous_cpus(cpus, smp_no_rendezvous_barrier, func,
  154             smp_no_rendezvous_barrier, arg);
  155 }
  156 
  157 static void
  158 dtrace_sync_func(void)
  159 {
  160 }
  161 
  162 void
  163 dtrace_sync(void)
  164 {
  165         dtrace_xcall(DTRACE_CPUALL, (dtrace_xcall_t)dtrace_sync_func, NULL);
  166 }
  167 
  168 /*
  169  * DTrace needs a high resolution time function which can
  170  * be called from a probe context and guaranteed not to have
  171  * instrumented with probes itself.
  172  *
  173  * Returns nanoseconds since boot.
  174  */
  175 uint64_t
  176 dtrace_gethrtime(void)
  177 {
  178         struct  timespec curtime;
  179 
  180         dtrace_getnanouptime(&curtime);
  181 
  182         return (curtime.tv_sec * 1000000000UL + curtime.tv_nsec);
  183 
  184 }
  185 
  186 uint64_t
  187 dtrace_gethrestime(void)
  188 {
  189         struct timespec current_time;
  190 
  191         dtrace_getnanotime(&current_time);
  192 
  193         return (current_time.tv_sec * 1000000000UL + current_time.tv_nsec);
  194 }
  195 
  196 /* Function to handle DTrace traps during probes. See amd64/amd64/trap.c */
  197 int
  198 dtrace_trap(struct trapframe *frame, u_int type)
  199 {
  200         /*
  201          * A trap can occur while DTrace executes a probe. Before
  202          * executing the probe, DTrace blocks re-scheduling and sets
  203          * a flag in its per-cpu flags to indicate that it doesn't
  204          * want to fault. On returning from the probe, the no-fault
  205          * flag is cleared and finally re-scheduling is enabled.
  206          *
  207          * Check if DTrace has enabled 'no-fault' mode:
  208          *
  209          */
  210         if ((cpu_core[curcpu].cpuc_dtrace_flags & CPU_DTRACE_NOFAULT) != 0) {
  211                 /*
  212                  * There are only a couple of trap types that are expected.
  213                  * All the rest will be handled in the usual way.
  214                  */
  215                 switch (type) {
  216                 /* Page fault. */
  217                 case FAULT_ALIGN:
  218                         /* Flag a bad address. */
  219                         cpu_core[curcpu].cpuc_dtrace_flags |= CPU_DTRACE_BADADDR;
  220                         cpu_core[curcpu].cpuc_dtrace_illval = 0;
  221 
  222                         /*
  223                          * Offset the instruction pointer to the instruction
  224                          * following the one causing the fault.
  225                          */
  226                         frame->tf_pc += sizeof(int);
  227                         return (1);
  228                 default:
  229                         /* Handle all other traps in the usual way. */
  230                         break;
  231                 }
  232         }
  233 
  234         /* Handle the trap in the usual way. */
  235         return (0);
  236 }
  237 
  238 void
  239 dtrace_probe_error(dtrace_state_t *state, dtrace_epid_t epid, int which,
  240     int fault, int fltoffs, uintptr_t illval)
  241 {
  242 
  243         dtrace_probe(dtrace_probeid_error, (uint64_t)(uintptr_t)state,
  244             (uintptr_t)epid,
  245             (uintptr_t)which, (uintptr_t)fault, (uintptr_t)fltoffs);
  246 }
  247 
  248 static int
  249 dtrace_invop_start(struct trapframe *frame)
  250 {
  251         register_t *r0, *sp;
  252         int data, invop, reg, update_sp;
  253 
  254         invop = dtrace_invop(frame->tf_pc, frame, frame->tf_r0);
  255         switch (invop & DTRACE_INVOP_MASK) {
  256         case DTRACE_INVOP_PUSHM:
  257                 sp = (register_t *)frame->tf_svc_sp;
  258                 r0 = &frame->tf_r0;
  259                 data = DTRACE_INVOP_DATA(invop);
  260 
  261                 /*
  262                  * Store the pc, lr, and sp. These have their own
  263                  * entries in the struct.
  264                  */
  265                 if (data & (1 << BIT_PC)) {
  266                         sp--;
  267                         *sp = frame->tf_pc;
  268                 }
  269                 if (data & (1 << BIT_LR)) {
  270                         sp--;
  271                         *sp = frame->tf_svc_lr;
  272                 }
  273                 if (data & (1 << BIT_SP)) {
  274                         sp--;
  275                         *sp = frame->tf_svc_sp;
  276                 }
  277 
  278                 /* Store the general registers */
  279                 for (reg = 12; reg >= 0; reg--) {
  280                         if (data & (1 << reg)) {
  281                                 sp--;
  282                                 *sp = r0[reg];
  283                         }
  284                 }
  285 
  286                 /* Update the stack pointer and program counter to continue */
  287                 frame->tf_svc_sp = (register_t)sp;
  288                 frame->tf_pc += 4;
  289                 break;
  290         case DTRACE_INVOP_POPM:
  291                 sp = (register_t *)frame->tf_svc_sp;
  292                 r0 = &frame->tf_r0;
  293                 data = DTRACE_INVOP_DATA(invop);
  294 
  295                 /* Read the general registers */
  296                 for (reg = 0; reg <= 12; reg++) {
  297                         if (data & (1 << reg)) {
  298                                 r0[reg] = *sp;
  299                                 sp++;
  300                         }
  301                 }
  302 
  303                 /*
  304                  * Set the stack pointer. If we don't update it here we will
  305                  * need to update it at the end as the instruction would do
  306                  */
  307                 update_sp = 1;
  308                 if (data & (1 << BIT_SP)) {
  309                         frame->tf_svc_sp = *sp;
  310                         *sp++;
  311                         update_sp = 0;
  312                 }
  313 
  314                 /* Update the link register, we need to use the correct copy */
  315                 if (data & (1 << BIT_LR)) {
  316                         frame->tf_svc_lr = *sp;
  317                         *sp++;
  318                 }
  319                 /*
  320                  * And the program counter. If it's not in the list skip over
  321                  * it when we return so to not hit this again.
  322                  */
  323                 if (data & (1 << BIT_PC)) {
  324                         frame->tf_pc = *sp;
  325                         *sp++;
  326                 } else
  327                         frame->tf_pc += 4;
  328 
  329                 /* Update the stack pointer if we haven't already done so */
  330                 if (update_sp)
  331                         frame->tf_svc_sp = (register_t)sp;
  332                 break;
  333         case DTRACE_INVOP_B:
  334                 data = DTRACE_INVOP_DATA(invop) & 0x00ffffff;
  335                 /* Sign extend the data */
  336                 if ((data & (1 << 23)) != 0)
  337                         data |= 0xff000000;
  338                 /* The data is the number of 4-byte words to change the pc */
  339                 data *= 4;
  340                 data += 8;
  341                 frame->tf_pc += data;
  342                 break;
  343         default:
  344                 return (-1);
  345                 break;
  346         }
  347 
  348         return (0);
  349 }
  350 
  351 void dtrace_invop_init(void)
  352 {
  353         dtrace_invop_jump_addr = dtrace_invop_start;
  354 }
  355 
  356 void dtrace_invop_uninit(void)
  357 {
  358         dtrace_invop_jump_addr = 0;
  359 }
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FreeBSD/Linux Kernel Cross Reference sys/cddl/dev/dtrace/arm/dtrace_subr.c

FreeBSD/Linux Kernel Cross Reference
sys/cddl/dev/dtrace/arm/dtrace_subr.c
