bsd/dev/i386/sdt_x86.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 /*
  22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #include <kern/cpu_data.h>
  27 #include <kern/thread.h>
  28 #include <mach/thread_status.h>
  29 #include <mach/vm_param.h>
  30
  31 #include <sys/dtrace.h>
  32 #include <sys/dtrace_impl.h>
  33
  34 #include <sys/dtrace_glue.h>
  35
  36 #include <sys/sdt_impl.h>
  37
  38 extern sdt_probe_t      **sdt_probetab;
  39
  40 /*ARGSUSED*/
  41 int
  42 sdt_invop(uintptr_t addr, uintptr_t *stack, uintptr_t eax)
  43 {
  44 #pragma unused(eax)
  45         sdt_probe_t *sdt = sdt_probetab[SDT_ADDR2NDX(addr)];
  46
  47         for (; sdt != NULL; sdt = sdt->sdp_hashnext) {
  48                 if ((uintptr_t)sdt->sdp_patchpoint == addr) {
  49                         x86_saved_state64_t *regs = (x86_saved_state64_t *)stack;
  50
  51                         dtrace_probe(sdt->sdp_id, regs->rdi, regs->rsi, regs->rdx, regs->rcx, regs->r8);
  52
  53                         return DTRACE_INVOP_NOP;
  54                 }
  55         }
  56
  57         return 0;
  58 }
  59
  60
  61 struct frame {
  62         struct frame *backchain;
  63         uintptr_t retaddr;
  64 };
  65
  66 /*ARGSUSED*/
  67 uint64_t
  68 sdt_getarg(void *arg, dtrace_id_t id, void *parg, int argno, int aframes)
  69 {
  70 #pragma unused(arg, id, parg)
  71         uint64_t val;
  72         struct frame *fp = (struct frame *)__builtin_frame_address(0);
  73         uintptr_t *stack;
  74         uintptr_t pc;
  75         int i;
  76
  77         /*
  78          * A total of 6 arguments are passed via registers; any argument with
  79          * index of 5 or lower is therefore in a register.
  80          */
  81         int inreg = 5;
  82
  83         for (i = 1; i <= aframes; i++) {
  84                 fp = fp->backchain;
  85                 pc = fp->retaddr;
  86
  87                 if (dtrace_invop_callsite_pre != NULL
  88                     && pc > (uintptr_t)dtrace_invop_callsite_pre
  89                     && pc <= (uintptr_t)dtrace_invop_callsite_post) {
  90                         /*
  91                          * In the case of x86_64, we will use the pointer to the
  92                          * save area structure that was pushed when we took the
  93                          * trap.  To get this structure, we must increment
  94                          * beyond the frame structure. If the
  95                          * argument that we're seeking is passed on the stack,
  96                          * we'll pull the true stack pointer out of the saved
  97                          * registers and decrement our argument by the number
  98                          * of arguments passed in registers; if the argument
  99                          * we're seeking is passed in regsiters, we can just
 100                          * load it directly.
 101                          */
 102
 103                         /* fp points to frame of dtrace_invop() activation. */
 104                         fp = fp->backchain; /* to fbt_perfcallback() activation. */
 105                         fp = fp->backchain; /* to kernel_trap() activation. */
 106                         fp = fp->backchain; /* to trap_from_kernel() activation. */
 107
 108                         x86_saved_state_t   *tagged_regs = (x86_saved_state_t *)&fp[1];
 109                         x86_saved_state64_t *saved_state = saved_state64(tagged_regs);
 110
 111                         if (argno <= inreg) {
 112                                 stack = (uintptr_t *)(void*)&saved_state->rdi;
 113                         } else {
 114                                 fp = (struct frame *)(saved_state->isf.rsp);
 115                                 stack = (uintptr_t *)&fp[0]; /* Find marshalled
 116                                                               *  arguments */
 117                                 argno -= (inreg + 1);
 118                         }
 119                         goto load;
 120                 }
 121         }
 122
 123         /*
 124          * We know that we did not come through a trap to get into
 125          * dtrace_probe() --  We arrive here when the provider has
 126          * called dtrace_probe() directly.
 127          * The probe ID is the first argument to dtrace_probe().
 128          * We must advance beyond that to get the argX.
 129          */
 130         argno++; /* Advance past probeID */
 131
 132         if (argno <= inreg) {
 133                 /*
 134                  * This shouldn't happen.  If the argument is passed in a
 135                  * register then it should have been, well, passed in a
 136                  * register...
 137                  */
 138                 DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
 139                 return 0;
 140         }
 141
 142         argno -= (inreg + 1);
 143         stack = (uintptr_t *)&fp[1]; /* Find marshalled arguments */
 144
 145 load:
 146         DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
 147         /* dtrace_probe arguments arg0 ... arg4 are 64bits wide */
 148         val = (uint64_t)(*(((uintptr_t *)stack) + argno));
 149         DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
 150
 151         return val;
 152 }