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 /* #pragma ident        "@(#)sdt.c      1.6     06/03/24 SMI" */
  27
  28 #ifdef KERNEL
  29 #ifndef _KERNEL
  30 #define _KERNEL /* Solaris vs. Darwin */
  31 #endif
  32 #endif
  33
  34 #define MACH__POSIX_C_SOURCE_PRIVATE 1 /* pulls in suitable savearea from mach/ppc/thread_status.h */
  35 #include <kern/cpu_data.h>
  36 #include <kern/thread.h>
  37 #include <mach/thread_status.h>
  38 #include <mach/vm_param.h>
  39
  40 #include <sys/dtrace.h>
  41 #include <sys/dtrace_impl.h>
  42
  43 #include <sys/dtrace_glue.h>
  44
  45 #include <sys/sdt_impl.h>
  46
  47 extern sdt_probe_t      **sdt_probetab;
  48
  49 int
  50 sdt_invop(__unused uintptr_t addr, __unused uintptr_t *stack, __unused uintptr_t eax)
  51 {
  52 #pragma unused(eax)
  53         sdt_probe_t *sdt = sdt_probetab[SDT_ADDR2NDX(addr)];
  54
  55         for (; sdt != NULL; sdt = sdt->sdp_hashnext) {
  56                 if ((uintptr_t) sdt->sdp_patchpoint == addr) {
  57                         struct arm_saved_state* regs = (struct arm_saved_state*) stack;
  58                         uintptr_t stack4 = *((uintptr_t*) regs->sp);
  59
  60                         dtrace_probe(sdt->sdp_id, regs->r[0], regs->r[1], regs->r[2], regs->r[3], stack4);
  61
  62                         return (DTRACE_INVOP_NOP);
  63                 }
  64         }
  65
  66         return (0);
  67 }
  68
  69 struct frame {
  70         struct frame *backchain;
  71         uintptr_t retaddr;
  72 };
  73
  74 /*ARGSUSED*/
  75 uint64_t
  76 sdt_getarg(void *arg, dtrace_id_t id, void *parg, int argno, int aframes)
  77 {
  78 #pragma unused(arg,id,parg)     /* __APPLE__ */
  79         uint64_t val = 0;
  80         struct frame *fp = (struct frame *)__builtin_frame_address(0);
  81         uintptr_t *stack;
  82         uintptr_t pc;
  83         int i;
  84
  85         /*
  86          * On ARM, up to four args are passed via registers; r0,r1,r2,r3
  87          * So coming into this function, arg >= 4 should be on the stack.
  88          * e.g. arg==5 refers to the 6th arg passed to the probed function.
  89          */
  90         int inreg = 4;
  91
  92         for (i = 1; i <= aframes; i++) {
  93                 fp = fp->backchain;
  94                 pc = fp->retaddr;
  95
  96                 if (dtrace_invop_callsite_pre != NULL
  97                         && pc  >  (uintptr_t)dtrace_invop_callsite_pre
  98                         && pc  <= (uintptr_t)dtrace_invop_callsite_post) {
  99
 100                         /*
 101                          * When we pass through the invalid op handler,
 102                          * we expect to find the save area structure,
 103                          * pushed on the stack where we took the trap.
 104                          * If the argument we seek is passed in a register, then
 105                          * we can load it directly from this saved area.
 106                          * If the argument we seek is passed on the stack, then
 107                          * we increment the frame pointer further, to find the
 108                          * pushed args
 109                          */
 110
 111                         /* fp points to the dtrace_invop activation */
 112                         fp = fp->backchain; /* to the fbt_perfCallback activation */
 113                         fp = fp->backchain; /* to the sleh_undef activation */
 114
 115 #if __BIGGEST_ALIGNMENT__ > 4
 116                         /**
 117                          * rdar://problem/24228656: On armv7k, the stack is realigned in sleh_undef2 to
 118                          * be 16-bytes aligned and the old value is pushed to
 119                          * the stack, so we retrieve it from here
 120                          */
 121                         arm_saved_state_t *saved_state = (arm_saved_state_t *)(uintptr_t*)*((uintptr_t *)&fp[1]);
 122 #else
 123                         arm_saved_state_t *saved_state = (arm_saved_state_t *)((uintptr_t *)&fp[1]);
 124 #endif
 125                         if (argno <= inreg) {
 126                                 /* For clarity only... should not get here */
 127                                 stack = (uintptr_t *)&saved_state->r[0];
 128                         } else {
 129                                 fp = (struct frame *)(saved_state->sp);
 130                                 stack = (uintptr_t *)&fp[0]; /* Find marshalled arguments */
 131                                 argno -= inreg;
 132                         }
 133                         goto load;
 134                 }
 135         }
 136
 137         /*
 138          * We know that we did not come through a trap to get into
 139          * dtrace_probe() --  We arrive here when the provider has
 140          * called dtrace_probe() directly.
 141          * The probe ID is the first argument to dtrace_probe().
 142          * We must advance beyond that to get the argX.
 143          */
 144         argno++; /* Advance past probeID */
 145
 146         if (argno <= inreg) {
 147                 /*
 148                  * This shouldn't happen.  If the argument is passed in a
 149                  * register then it should have been, well, passed in a
 150                  * register...
 151                  */
 152                 DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
 153                 return (0);
 154         }
 155
 156         argno -= (inreg + 1);
 157         stack = (uintptr_t *)&fp[1]; /* Find marshalled arguments */
 158
 159 load:
 160         DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
 161         /* dtrace_probe arguments arg0 .. arg4 are 64bits wide */
 162         val = (uint64_t)(*(((uintptr_t *)stack) + argno));
 163         DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
 164         return (val);
 165
 166 }