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            0x7ffff808
  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 #define FBT_AFRAMES     7
  52
  53 int
  54 fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t rval)
  55 {
  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                         if (fbt->fbtp_roffset == 0) {
  63                                 cpu->cpu_dtrace_caller = addr;
  64
  65                                 dtrace_probe(fbt->fbtp_id, frame->fixreg[3],
  66                                     frame->fixreg[4], frame->fixreg[5],
  67                                     frame->fixreg[6], frame->fixreg[7]);
  68
  69                                 cpu->cpu_dtrace_caller = 0;
  70                         } else {
  71
  72                                 dtrace_probe(fbt->fbtp_id, fbt->fbtp_roffset,
  73                                     rval, 0, 0, 0);
  74                                 /*
  75                                  * The caller doesn't have the fbt item, so
  76                                  * fixup tail calls here.
  77                                  */
  78                                 if (fbt->fbtp_rval == DTRACE_INVOP_JUMP) {
  79                                         frame->srr0 = (uintptr_t)fbt->fbtp_patchpoint;
  80                                         tmp = fbt->fbtp_savedval & FBT_BR_MASK;
  81                                         /* Sign extend. */
  82                                         if (tmp & 0x02000000)
  83 #ifdef __powerpc64__
  84                                                 tmp |= 0xfffffffffc000000ULL;
  85 #else
  86                                                 tmp |= 0xfc000000UL;
  87 #endif
  88                                         frame->srr0 += tmp;
  89                                 }
  90                                 cpu->cpu_dtrace_caller = 0;
  91                         }
  92
  93                         return (fbt->fbtp_rval);
  94                 }
  95         }
  96
  97         return (0);
  98 }
  99
 100 void
 101 fbt_patch_tracepoint(fbt_probe_t *fbt, fbt_patchval_t val)
 102 {
 103
 104         *fbt->fbtp_patchpoint = val;
 105         __syncicache(fbt->fbtp_patchpoint, 4);
 106 }
 107
 108 int
 109 fbt_provide_module_function(linker_file_t lf, int symindx,
 110     linker_symval_t *symval, void *opaque)
 111 {
 112         char *modname = opaque;
 113         const char *name = symval->name;
 114         fbt_probe_t *fbt, *retfbt;
 115         int j;
 116         uint32_t *instr, *limit;
 117
 118 #ifdef __powerpc64__
 119 #if !defined(_CALL_ELF) || _CALL_ELF == 1
 120         /*
 121          * PowerPC64 uses '.' prefixes on symbol names, ignore it, but only
 122          * allow symbols with the '.' prefix, so that we don't get the function
 123          * descriptor instead.
 124          */
 125         if (name[0] == '.')
 126                 name++;
 127         else
 128                 return (0);
 129 #endif
 130 #endif
 131
 132         if (fbt_excluded(name))
 133                 return (0);
 134
 135         instr = (uint32_t *) symval->value;
 136         limit = (uint32_t *) (symval->value + symval->size);
 137
 138         for (; instr < limit; instr++)
 139                 if (*instr == FBT_MFLR_R0)
 140                         break;
 141
 142         if (*instr != FBT_MFLR_R0)
 143                 return (0);
 144
 145         fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
 146         fbt->fbtp_name = name;
 147         fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
 148             name, FBT_ENTRY, FBT_AFRAMES, fbt);
 149         fbt->fbtp_patchpoint = instr;
 150         fbt->fbtp_ctl = lf;
 151         fbt->fbtp_loadcnt = lf->loadcnt;
 152         fbt->fbtp_savedval = *instr;
 153         fbt->fbtp_patchval = FBT_PATCHVAL;
 154         fbt->fbtp_rval = DTRACE_INVOP_MFLR_R0;
 155         fbt->fbtp_symindx = symindx;
 156
 157         fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
 158         fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;
 159
 160         lf->fbt_nentries++;
 161
 162         retfbt = NULL;
 163 again:
 164         if (instr >= limit)
 165                 return (0);
 166
 167         /*
 168          * We (desperately) want to avoid erroneously instrumenting a
 169          * jump table. To determine if we're looking at a true instruction
 170          * sequence or an inline jump table that happens to contain the same
 171          * byte sequences, we resort to some heuristic sleeze:  we treat this
 172          * instruction as being contained within a pointer, and see if that
 173          * pointer points to within the body of the function.  If it does, we
 174          * refuse to instrument it.
 175          */
 176         {
 177                 uint32_t *ptr;
 178
 179                 ptr = *(uint32_t **)instr;
 180
 181                 if (ptr >= (uint32_t *) symval->value && ptr < limit) {
 182                         instr++;
 183                         goto again;
 184                 }
 185         }
 186
 187         if (*instr != FBT_MTLR_R0) {
 188                 instr++;
 189                 goto again;
 190         }
 191
 192         instr++;
 193
 194         for (j = 0; j < 12 && instr < limit; j++, instr++) {
 195                 if ((*instr == FBT_BCTR) || (*instr == FBT_BLR) ||
 196                     FBT_IS_JUMP(*instr))
 197                         break;
 198         }
 199
 200         if (!(*instr == FBT_BCTR || *instr == FBT_BLR || FBT_IS_JUMP(*instr)))
 201                 goto again;
 202
 203         /*
 204          * We have a winner!
 205          */
 206         fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
 207         fbt->fbtp_name = name;
 208
 209         if (retfbt == NULL) {
 210                 fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
 211                     name, FBT_RETURN, FBT_AFRAMES, fbt);
 212         } else {
 213                 retfbt->fbtp_probenext = fbt;
 214                 fbt->fbtp_id = retfbt->fbtp_id;
 215         }
 216
 217         retfbt = fbt;
 218         fbt->fbtp_patchpoint = instr;
 219         fbt->fbtp_ctl = lf;
 220         fbt->fbtp_loadcnt = lf->loadcnt;
 221         fbt->fbtp_symindx = symindx;
 222
 223         if (*instr == FBT_BCTR)
 224                 fbt->fbtp_rval = DTRACE_INVOP_BCTR;
 225         else if (*instr == FBT_BLR)
 226                 fbt->fbtp_rval = DTRACE_INVOP_BLR;
 227         else
 228                 fbt->fbtp_rval = DTRACE_INVOP_JUMP;
 229
 230         fbt->fbtp_roffset =
 231             (uintptr_t)((uint8_t *)instr - (uint8_t *)symval->value);
 232
 233         fbt->fbtp_savedval = *instr;
 234         fbt->fbtp_patchval = FBT_PATCHVAL;
 235         fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
 236         fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;
 237
 238         lf->fbt_nentries++;
 239
 240         instr += 4;
 241         goto again;
 242 }