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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
* Portions Copyright 2006-2008 John Birrell jb@freebsd.org
* Portions Copyright 2013 Justin Hibbits jhibbits@freebsd.org
*
* $FreeBSD$
*
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/dtrace.h>
#include <machine/md_var.h>
#include "fbt.h"
#define FBT_PATCHVAL 0x7ffff808
#define FBT_MFLR_R0 0x7c0802a6
#define FBT_MTLR_R0 0x7c0803a6
#define FBT_BLR 0x4e800020
#define FBT_BCTR 0x4e800030
#define FBT_BRANCH 0x48000000
#define FBT_BR_MASK 0x03fffffc
#define FBT_IS_JUMP(instr) ((instr & ~FBT_BR_MASK) == FBT_BRANCH)
#define FBT_ENTRY "entry"
#define FBT_RETURN "return"
#define FBT_AFRAMES 7
int
fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t rval)
{
solaris_cpu_t *cpu = &solaris_cpu[curcpu];
fbt_probe_t *fbt = fbt_probetab[FBT_ADDR2NDX(addr)];
uintptr_t tmp;
for (; fbt != NULL; fbt = fbt->fbtp_hashnext) {
if ((uintptr_t)fbt->fbtp_patchpoint == addr) {
if (fbt->fbtp_roffset == 0) {
cpu->cpu_dtrace_caller = addr;
dtrace_probe(fbt->fbtp_id, frame->fixreg[3],
frame->fixreg[4], frame->fixreg[5],
frame->fixreg[6], frame->fixreg[7]);
cpu->cpu_dtrace_caller = 0;
} else {
dtrace_probe(fbt->fbtp_id, fbt->fbtp_roffset,
rval, 0, 0, 0);
/*
* The caller doesn't have the fbt item, so
* fixup tail calls here.
*/
if (fbt->fbtp_rval == DTRACE_INVOP_JUMP) {
frame->srr0 = (uintptr_t)fbt->fbtp_patchpoint;
tmp = fbt->fbtp_savedval & FBT_BR_MASK;
/* Sign extend. */
if (tmp & 0x02000000)
#ifdef __powerpc64__
tmp |= 0xfffffffffc000000ULL;
#else
tmp |= 0xfc000000UL;
#endif
frame->srr0 += tmp;
}
cpu->cpu_dtrace_caller = 0;
}
return (fbt->fbtp_rval);
}
}
return (0);
}
void
fbt_patch_tracepoint(fbt_probe_t *fbt, fbt_patchval_t val)
{
*fbt->fbtp_patchpoint = val;
__syncicache(fbt->fbtp_patchpoint, 4);
}
int
fbt_provide_module_function(linker_file_t lf, int symindx,
linker_symval_t *symval, void *opaque)
{
char *modname = opaque;
const char *name = symval->name;
fbt_probe_t *fbt, *retfbt;
int j;
uint32_t *instr, *limit;
#ifdef __powerpc64__
/*
* PowerPC64 uses '.' prefixes on symbol names, ignore it, but only
* allow symbols with the '.' prefix, so that we don't get the function
* descriptor instead.
*/
if (name[0] == '.')
name++;
else
return (0);
#endif
if (strncmp(name, "dtrace_", 7) == 0 &&
strncmp(name, "dtrace_safe_", 12) != 0) {
/*
* Anything beginning with "dtrace_" may be called
* from probe context unless it explicitly indicates
* that it won't be called from probe context by
* using the prefix "dtrace_safe_".
*/
return (0);
}
instr = (uint32_t *) symval->value;
limit = (uint32_t *) (symval->value + symval->size);
for (; instr < limit; instr++)
if (*instr == FBT_MFLR_R0)
break;
if (*instr != FBT_MFLR_R0)
return (0);
fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
fbt->fbtp_name = name;
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
name, FBT_ENTRY, FBT_AFRAMES, fbt);
fbt->fbtp_patchpoint = instr;
fbt->fbtp_ctl = lf;
fbt->fbtp_loadcnt = lf->loadcnt;
fbt->fbtp_savedval = *instr;
fbt->fbtp_patchval = FBT_PATCHVAL;
fbt->fbtp_rval = DTRACE_INVOP_MFLR_R0;
fbt->fbtp_symindx = symindx;
fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;
lf->fbt_nentries++;
retfbt = NULL;
again:
if (instr >= limit)
return (0);
/*
* We (desperately) want to avoid erroneously instrumenting a
* jump table. To determine if we're looking at a true instruction
* sequence or an inline jump table that happens to contain the same
* byte sequences, we resort to some heuristic sleeze: we treat this
* instruction as being contained within a pointer, and see if that
* pointer points to within the body of the function. If it does, we
* refuse to instrument it.
*/
{
uint32_t *ptr;
ptr = *(uint32_t **)instr;
if (ptr >= (uint32_t *) symval->value && ptr < limit) {
instr++;
goto again;
}
}
if (*instr != FBT_MTLR_R0) {
instr++;
goto again;
}
instr++;
for (j = 0; j < 12 && instr < limit; j++, instr++) {
if ((*instr == FBT_BCTR) || (*instr == FBT_BLR) ||
FBT_IS_JUMP(*instr))
break;
}
if (!(*instr == FBT_BCTR || *instr == FBT_BLR || FBT_IS_JUMP(*instr)))
goto again;
/*
* We have a winner!
*/
fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
fbt->fbtp_name = name;
if (retfbt == NULL) {
fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
name, FBT_RETURN, FBT_AFRAMES, fbt);
} else {
retfbt->fbtp_next = fbt;
fbt->fbtp_id = retfbt->fbtp_id;
}
retfbt = fbt;
fbt->fbtp_patchpoint = instr;
fbt->fbtp_ctl = lf;
fbt->fbtp_loadcnt = lf->loadcnt;
fbt->fbtp_symindx = symindx;
if (*instr == FBT_BCTR)
fbt->fbtp_rval = DTRACE_INVOP_BCTR;
else if (*instr == FBT_BLR)
fbt->fbtp_rval = DTRACE_INVOP_RET;
else
fbt->fbtp_rval = DTRACE_INVOP_JUMP;
fbt->fbtp_roffset =
(uintptr_t)((uint8_t *)instr - (uint8_t *)symval->value);
fbt->fbtp_savedval = *instr;
fbt->fbtp_patchval = FBT_PATCHVAL;
fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;
lf->fbt_nentries++;
instr += 4;
goto again;
}
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