sys/cddl/dev/fbt/powerpc/fbt_isa.c

   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 (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  *
  21  * Portions Copyright 2006-2008 John Birrell jb@freebsd.org
  22  * Portions Copyright 2013 Justin Hibbits jhibbits@freebsd.org
  23  *
  24  * $FreeBSD$
  25  *
  26  */
  27
  28 /*
  29  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  30  * Use is subject to license terms.
  31  */
  32
  33 #include <sys/cdefs.h>
  34 #include <sys/param.h>
  35 #include <sys/dtrace.h>
  36 #include <machine/md_var.h>
  37
  38 #include "fbt.h"
  39
  40 #define FBT_PATCHVAL            0x7c810808
  41 #define FBT_MFLR_R0             0x7c0802a6
  42 #define FBT_MTLR_R0             0x7c0803a6
  43 #define FBT_BLR                 0x4e800020
  44 #define FBT_BCTR                0x4e800030
  45 #define FBT_BRANCH              0x48000000
  46 #define FBT_BR_MASK             0x03fffffc
  47 #define FBT_IS_JUMP(instr)      ((instr & ~FBT_BR_MASK) == FBT_BRANCH)
  48
  49 #define FBT_ENTRY       "entry"
  50 #define FBT_RETURN      "return"
  51
  52 int
  53 fbt_invop(uintptr_t addr, uintptr_t *stack, uintptr_t rval)
  54 {
  55         struct trapframe *frame = (struct trapframe *)stack;
  56         solaris_cpu_t *cpu = &solaris_cpu[curcpu];
  57         fbt_probe_t *fbt = fbt_probetab[FBT_ADDR2NDX(addr)];
  58         uintptr_t tmp;
  59
  60         for (; fbt != NULL; fbt = fbt->fbtp_hashnext) {
  61                 if ((uintptr_t)fbt->fbtp_patchpoint == addr) {
  62                         fbt->fbtp_invop_cnt++;
  63                         if (fbt->fbtp_roffset == 0) {
  64                                 cpu->cpu_dtrace_caller = addr;
  65
  66                                 dtrace_probe(fbt->fbtp_id, frame->fixreg[3],
  67                                     frame->fixreg[4], frame->fixreg[5],
  68                                     frame->fixreg[6], frame->fixreg[7]);
  69
  70                                 cpu->cpu_dtrace_caller = 0;
  71                         } else {
  72
  73                                 dtrace_probe(fbt->fbtp_id, fbt->fbtp_roffset,
  74                                     rval, 0, 0, 0);
  75                                 /*
  76                                  * The caller doesn't have the fbt item, so
  77                                  * fixup tail calls here.
  78                                  */
  79                                 if (fbt->fbtp_rval == DTRACE_INVOP_JUMP) {
  80                                         frame->srr0 = (uintptr_t)fbt->fbtp_patchpoint;
  81                                         tmp = fbt->fbtp_savedval & FBT_BR_MASK;
  82                                         /* Sign extend. */
  83                                         if (tmp & 0x02000000)
  84 #ifdef __powerpc64__
  85                                                 tmp |= 0xfffffffffc000000ULL;
  86 #else
  87                                                 tmp |= 0xfc000000UL;
  88 #endif
  89                                         frame->srr0 += tmp;
  90                                 }
  91                                 cpu->cpu_dtrace_caller = 0;
  92                         }
  93
  94                         return (fbt->fbtp_rval);
  95                 }
  96         }
  97
  98         return (0);
  99 }
 100
 101 void
 102 fbt_patch_tracepoint(fbt_probe_t *fbt, fbt_patchval_t val)
 103 {
 104
 105         *fbt->fbtp_patchpoint = val;
 106         __syncicache(fbt->fbtp_patchpoint, 4);
 107 }
 108
 109 int
 110 fbt_provide_module_function(linker_file_t lf, int symindx,
 111     linker_symval_t *symval, void *opaque)
 112 {
 113         char *modname = opaque;
 114         const char *name = symval->name;
 115         fbt_probe_t *fbt, *retfbt;
 116         int j;
 117         uint32_t *instr, *limit;
 118
 119         /* PowerPC64 uses '.' prefixes on symbol names, ignore it. */
 120         if (name[0] == '.')
 121                 name++;
 122
 123         if (strncmp(name, "dtrace_", 7) == 0 &&
 124             strncmp(name, "dtrace_safe_", 12) != 0) {
 125                 /*
 126                  * Anything beginning with "dtrace_" may be called
 127                  * from probe context unless it explicitly indicates
 128                  * that it won't be called from probe context by
 129                  * using the prefix "dtrace_safe_".
 130                  */
 131                 return (0);
 132         }
 133
 134         if (name[0] == '_' && name[1] == '_')
 135                 return (0);
 136
 137         instr = (uint32_t *) symval->value;
 138         limit = (uint32_t *) (symval->value + symval->size);
 139
 140         for (; instr < limit; instr++)
 141                 if (*instr == FBT_MFLR_R0)
 142                         break;
 143
 144         if (*instr != FBT_MFLR_R0)
 145                 return (0);
 146
 147         fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
 148         fbt->fbtp_name = name;
 149         fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
 150             name, FBT_ENTRY, 7, fbt);
 151         fbt->fbtp_patchpoint = instr;
 152         fbt->fbtp_ctl = lf;
 153         fbt->fbtp_loadcnt = lf->loadcnt;
 154         fbt->fbtp_savedval = *instr;
 155         fbt->fbtp_patchval = FBT_PATCHVAL;
 156         fbt->fbtp_rval = DTRACE_INVOP_MFLR_R0;
 157         fbt->fbtp_symindx = symindx;
 158
 159         fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
 160         fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;
 161
 162         lf->fbt_nentries++;
 163
 164         retfbt = NULL;
 165 again:
 166         if (instr >= limit)
 167                 return (0);
 168
 169         /*
 170          * We (desperately) want to avoid erroneously instrumenting a
 171          * jump table. To determine if we're looking at a true instruction
 172          * sequence or an inline jump table that happens to contain the same
 173          * byte sequences, we resort to some heuristic sleeze:  we treat this
 174          * instruction as being contained within a pointer, and see if that
 175          * pointer points to within the body of the function.  If it does, we
 176          * refuse to instrument it.
 177          */
 178         {
 179                 uint32_t *ptr;
 180
 181                 ptr = *(uint32_t **)instr;
 182
 183                 if (ptr >= (uint32_t *) symval->value && ptr < limit) {
 184                         instr++;
 185                         goto again;
 186                 }
 187         }
 188
 189         if (*instr != FBT_MTLR_R0) {
 190                 instr++;
 191                 goto again;
 192         }
 193
 194         instr++;
 195
 196         for (j = 0; j < 12 && instr < limit; j++, instr++) {
 197                 if ((*instr == FBT_BCTR) || (*instr == FBT_BLR) ||
 198                     FBT_IS_JUMP(*instr))
 199                         break;
 200         }
 201
 202         if (!(*instr == FBT_BCTR || *instr == FBT_BLR || FBT_IS_JUMP(*instr)))
 203                 goto again;
 204
 205         /*
 206          * We have a winner!
 207          */
 208         fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
 209         fbt->fbtp_name = name;
 210
 211         if (retfbt == NULL) {
 212                 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
 213                     name, FBT_RETURN, 7, fbt);
 214         } else {
 215                 retfbt->fbtp_next = fbt;
 216                 fbt->fbtp_id = retfbt->fbtp_id;
 217         }
 218
 219         retfbt = fbt;
 220         fbt->fbtp_patchpoint = instr;
 221         fbt->fbtp_ctl = lf;
 222         fbt->fbtp_loadcnt = lf->loadcnt;
 223         fbt->fbtp_symindx = symindx;
 224
 225         if (*instr == FBT_BCTR)
 226                 fbt->fbtp_rval = DTRACE_INVOP_BCTR;
 227         else if (*instr == FBT_BLR)
 228                 fbt->fbtp_rval = DTRACE_INVOP_RET;
 229         else
 230                 fbt->fbtp_rval = DTRACE_INVOP_JUMP;
 231
 232         fbt->fbtp_savedval = *instr;
 233         fbt->fbtp_patchval = FBT_PATCHVAL;
 234         fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
 235         fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;
 236
 237         lf->fbt_nentries++;
 238
 239         instr += 4;
 240         goto again;
 241 }