bsd/dev/arm/sdt_arm.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 2006 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 int
  41 sdt_invop(__unused uintptr_t addr, __unused uintptr_t *stack, __unused uintptr_t eax)
  42 {
  43 #pragma unused(eax)
  44         sdt_probe_t *sdt = sdt_probetab[SDT_ADDR2NDX(addr)];
  45
  46         for (; sdt != NULL; sdt = sdt->sdp_hashnext) {
  47                 if ((uintptr_t) sdt->sdp_patchpoint == addr) {
  48                         struct arm_saved_state* regs = (struct arm_saved_state*) stack;
  49                         uintptr_t stack4 = *((uintptr_t*) regs->sp);
  50
  51                         dtrace_probe(sdt->sdp_id, regs->r[0], regs->r[1], regs->r[2], regs->r[3], stack4);
  52
  53                         return DTRACE_INVOP_NOP;
  54                 }
  55         }
  56
  57         return 0;
  58 }
  59
  60 struct frame {
  61         struct frame *backchain;
  62         uintptr_t retaddr;
  63 };
  64
  65 /*ARGSUSED*/
  66 uint64_t
  67 sdt_getarg(void *arg, dtrace_id_t id, void *parg, int argno, int aframes)
  68 {
  69 #pragma unused(arg,id,parg)     /* __APPLE__ */
  70         uint64_t val = 0;
  71         struct frame *fp = (struct frame *)__builtin_frame_address(0);
  72         uintptr_t *stack;
  73         uintptr_t pc;
  74         int i;
  75
  76         /*
  77          * On ARM, up to four args are passed via registers; r0,r1,r2,r3
  78          * So coming into this function, arg >= 4 should be on the stack.
  79          * e.g. arg==5 refers to the 6th arg passed to the probed function.
  80          */
  81         int inreg = 4;
  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                          * When we pass through the invalid op handler,
  92                          * we expect to find the save area structure,
  93                          * pushed on the stack where we took the trap.
  94                          * If the argument we seek is passed in a register, then
  95                          * we can load it directly from this saved area.
  96                          * If the argument we seek is passed on the stack, then
  97                          * we increment the frame pointer further, to find the
  98                          * pushed args
  99                          */
 100
 101                         /* fp points to the dtrace_invop activation */
 102                         fp = fp->backchain; /* to the fbt_perfCallback activation */
 103                         fp = fp->backchain; /* to the sleh_undef activation */
 104
 105 #if __BIGGEST_ALIGNMENT__ > 4
 106                         /**
 107                          * rdar://problem/24228656: On armv7k, the stack is realigned in sleh_undef2 to
 108                          * be 16-bytes aligned and the old value is pushed to
 109                          * the stack, so we retrieve it from here
 110                          */
 111                         arm_saved_state_t *saved_state = (arm_saved_state_t *)(uintptr_t*)*((uintptr_t *)&fp[1]);
 112 #else
 113                         arm_saved_state_t *saved_state = (arm_saved_state_t *)((uintptr_t *)&fp[1]);
 114 #endif
 115                         if (argno <= inreg) {
 116                                 /* For clarity only... should not get here */
 117                                 stack = (uintptr_t *)&saved_state->r[0];
 118                         } else {
 119                                 fp = (struct frame *)(saved_state->sp);
 120                                 stack = (uintptr_t *)&fp[0]; /* Find marshalled arguments */
 121                                 argno -= inreg;
 122                         }
 123                         goto load;
 124                 }
 125         }
 126
 127         /*
 128          * We know that we did not come through a trap to get into
 129          * dtrace_probe() --  We arrive here when the provider has
 130          * called dtrace_probe() directly.
 131          * The probe ID is the first argument to dtrace_probe().
 132          * We must advance beyond that to get the argX.
 133          */
 134         argno++; /* Advance past probeID */
 135
 136         if (argno <= inreg) {
 137                 /*
 138                  * This shouldn't happen.  If the argument is passed in a
 139                  * register then it should have been, well, passed in a
 140                  * register...
 141                  */
 142                 DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
 143                 return 0;
 144         }
 145
 146         argno -= (inreg + 1);
 147         stack = (uintptr_t *)&fp[1]; /* Find marshalled arguments */
 148
 149 load:
 150         DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
 151         /* dtrace_probe arguments arg0 .. arg4 are 64bits wide */
 152         val = (uint64_t)(*(((uintptr_t *)stack) + argno));
 153         DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
 154         return val;
 155 }