OpenSolaris_b135/uts/intel/dtrace/sdt.c
/*
* 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
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/modctl.h>
#include <sys/sunddi.h>
#include <sys/dtrace.h>
#include <sys/kobj.h>
#include <sys/stat.h>
#include <sys/conf.h>
#include <vm/seg_kmem.h>
#include <sys/stack.h>
#include <sys/frame.h>
#include <sys/dtrace_impl.h>
#include <sys/cmn_err.h>
#include <sys/sysmacros.h>
#include <sys/privregs.h>
#include <sys/sdt_impl.h>
#define SDT_PATCHVAL 0xf0
#define SDT_ADDR2NDX(addr) ((((uintptr_t)(addr)) >> 4) & sdt_probetab_mask)
#define SDT_PROBETAB_SIZE 0x1000 /* 4k entries -- 16K total */
static dev_info_t *sdt_devi;
static int sdt_verbose = 0;
static sdt_probe_t **sdt_probetab;
static int sdt_probetab_size;
static int sdt_probetab_mask;
/*ARGSUSED*/
static int
sdt_invop(uintptr_t addr, uintptr_t *stack, uintptr_t eax)
{
uintptr_t stack0, stack1, stack2, stack3, stack4;
int i = 0;
sdt_probe_t *sdt = sdt_probetab[SDT_ADDR2NDX(addr)];
#ifdef __amd64
/*
* On amd64, stack[0] contains the dereferenced stack pointer,
* stack[1] contains savfp, stack[2] contains savpc. We want
* to step over these entries.
*/
i += 3;
#endif
for (; sdt != NULL; sdt = sdt->sdp_hashnext) {
if ((uintptr_t)sdt->sdp_patchpoint == addr) {
/*
* When accessing the arguments on the stack, we must
* protect against accessing beyond the stack. We can
* safely set NOFAULT here -- we know that interrupts
* are already disabled.
*/
DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
stack0 = stack[i++];
stack1 = stack[i++];
stack2 = stack[i++];
stack3 = stack[i++];
stack4 = stack[i++];
DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT |
CPU_DTRACE_BADADDR);
dtrace_probe(sdt->sdp_id, stack0, stack1,
stack2, stack3, stack4);
return (DTRACE_INVOP_NOP);
}
}
return (0);
}
/*ARGSUSED*/
static void
sdt_provide_module(void *arg, struct modctl *ctl)
{
struct module *mp = ctl->mod_mp;
char *modname = ctl->mod_modname;
sdt_probedesc_t *sdpd;
sdt_probe_t *sdp, *old;
sdt_provider_t *prov;
int len;
/*
* One for all, and all for one: if we haven't yet registered all of
* our providers, we'll refuse to provide anything.
*/
for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) {
if (prov->sdtp_id == DTRACE_PROVNONE)
return;
}
if (mp->sdt_nprobes != 0 || (sdpd = mp->sdt_probes) == NULL)
return;
for (sdpd = mp->sdt_probes; sdpd != NULL; sdpd = sdpd->sdpd_next) {
char *name = sdpd->sdpd_name, *func, *nname;
int i, j;
sdt_provider_t *prov;
ulong_t offs;
dtrace_id_t id;
for (prov = sdt_providers; prov->sdtp_prefix != NULL; prov++) {
char *prefix = prov->sdtp_prefix;
if (strncmp(name, prefix, strlen(prefix)) == 0) {
name += strlen(prefix);
break;
}
}
nname = kmem_alloc(len = strlen(name) + 1, KM_SLEEP);
for (i = 0, j = 0; name[j] != '\0'; i++) {
if (name[j] == '_' && name[j + 1] == '_') {
nname[i] = '-';
j += 2;
} else {
nname[i] = name[j++];
}
}
nname[i] = '\0';
sdp = kmem_zalloc(sizeof (sdt_probe_t), KM_SLEEP);
sdp->sdp_loadcnt = ctl->mod_loadcnt;
sdp->sdp_ctl = ctl;
sdp->sdp_name = nname;
sdp->sdp_namelen = len;
sdp->sdp_provider = prov;
func = kobj_searchsym(mp, sdpd->sdpd_offset, &offs);
if (func == NULL)
func = "<unknown>";
/*
* We have our provider. Now create the probe.
*/
if ((id = dtrace_probe_lookup(prov->sdtp_id, modname,
func, nname)) != DTRACE_IDNONE) {
old = dtrace_probe_arg(prov->sdtp_id, id);
ASSERT(old != NULL);
sdp->sdp_next = old->sdp_next;
sdp->sdp_id = id;
old->sdp_next = sdp;
} else {
sdp->sdp_id = dtrace_probe_create(prov->sdtp_id,
modname, func, nname, 3, sdp);
mp->sdt_nprobes++;
}
sdp->sdp_hashnext =
sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)];
sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)] = sdp;
sdp->sdp_patchval = SDT_PATCHVAL;
sdp->sdp_patchpoint = (uint8_t *)sdpd->sdpd_offset;
sdp->sdp_savedval = *sdp->sdp_patchpoint;
}
}
/*ARGSUSED*/
static void
sdt_destroy(void *arg, dtrace_id_t id, void *parg)
{
sdt_probe_t *sdp = parg, *old, *last, *hash;
struct modctl *ctl = sdp->sdp_ctl;
int ndx;
if (ctl != NULL && ctl->mod_loadcnt == sdp->sdp_loadcnt) {
if ((ctl->mod_loadcnt == sdp->sdp_loadcnt &&
ctl->mod_loaded)) {
((struct module *)(ctl->mod_mp))->sdt_nprobes--;
}
}
while (sdp != NULL) {
old = sdp;
/*
* Now we need to remove this probe from the sdt_probetab.
*/
ndx = SDT_ADDR2NDX(sdp->sdp_patchpoint);
last = NULL;
hash = sdt_probetab[ndx];
while (hash != sdp) {
ASSERT(hash != NULL);
last = hash;
hash = hash->sdp_hashnext;
}
if (last != NULL) {
last->sdp_hashnext = sdp->sdp_hashnext;
} else {
sdt_probetab[ndx] = sdp->sdp_hashnext;
}
kmem_free(sdp->sdp_name, sdp->sdp_namelen);
sdp = sdp->sdp_next;
kmem_free(old, sizeof (sdt_probe_t));
}
}
/*ARGSUSED*/
static int
sdt_enable(void *arg, dtrace_id_t id, void *parg)
{
sdt_probe_t *sdp = parg;
struct modctl *ctl = sdp->sdp_ctl;
ctl->mod_nenabled++;
/*
* If this module has disappeared since we discovered its probes,
* refuse to enable it.
*/
if (!ctl->mod_loaded) {
if (sdt_verbose) {
cmn_err(CE_NOTE, "sdt is failing for probe %s "
"(module %s unloaded)",
sdp->sdp_name, ctl->mod_modname);
}
goto err;
}
/*
* Now check that our modctl has the expected load count. If it
* doesn't, this module must have been unloaded and reloaded -- and
* we're not going to touch it.
*/
if (ctl->mod_loadcnt != sdp->sdp_loadcnt) {
if (sdt_verbose) {
cmn_err(CE_NOTE, "sdt is failing for probe %s "
"(module %s reloaded)",
sdp->sdp_name, ctl->mod_modname);
}
goto err;
}
while (sdp != NULL) {
*sdp->sdp_patchpoint = sdp->sdp_patchval;
sdp = sdp->sdp_next;
}
err:
return (0);
}
/*ARGSUSED*/
static void
sdt_disable(void *arg, dtrace_id_t id, void *parg)
{
sdt_probe_t *sdp = parg;
struct modctl *ctl = sdp->sdp_ctl;
ctl->mod_nenabled--;
if (!ctl->mod_loaded || ctl->mod_loadcnt != sdp->sdp_loadcnt)
goto err;
while (sdp != NULL) {
*sdp->sdp_patchpoint = sdp->sdp_savedval;
sdp = sdp->sdp_next;
}
err:
;
}
/*ARGSUSED*/
uint64_t
sdt_getarg(void *arg, dtrace_id_t id, void *parg, int argno, int aframes)
{
uintptr_t val;
struct frame *fp = (struct frame *)dtrace_getfp();
uintptr_t *stack;
int i;
#if defined(__amd64)
/*
* A total of 6 arguments are passed via registers; any argument with
* index of 5 or lower is therefore in a register.
*/
int inreg = 5;
#endif
for (i = 1; i <= aframes; i++) {
fp = (struct frame *)(fp->fr_savfp);
if (fp->fr_savpc == (pc_t)dtrace_invop_callsite) {
#if !defined(__amd64)
/*
* If we pass through the invalid op handler, we will
* use the pointer that it passed to the stack as the
* second argument to dtrace_invop() as the pointer to
* the stack.
*/
stack = ((uintptr_t **)&fp[1])[1];
#else
/*
* In the case of amd64, we will use the pointer to the
* regs structure that was pushed when we took the
* trap. To get this structure, we must increment
* beyond the frame structure. If the argument that
* we're seeking is passed on the stack, we'll pull
* the true stack pointer out of the saved registers
* and decrement our argument by the number of
* arguments passed in registers; if the argument
* we're seeking is passed in regsiters, we can just
* load it directly.
*/
struct regs *rp = (struct regs *)((uintptr_t)&fp[1] +
sizeof (uintptr_t));
if (argno <= inreg) {
stack = (uintptr_t *)&rp->r_rdi;
} else {
stack = (uintptr_t *)(rp->r_rsp);
argno -= (inreg + 1);
}
#endif
goto load;
}
}
/*
* We know that we did not come through a trap to get into
* dtrace_probe() -- the provider simply called dtrace_probe()
* directly. As this is the case, we need to shift the argument
* that we're looking for: the probe ID is the first argument to
* dtrace_probe(), so the argument n will actually be found where
* one would expect to find argument (n + 1).
*/
argno++;
#if defined(__amd64)
if (argno <= inreg) {
/*
* This shouldn't happen. If the argument is passed in a
* register then it should have been, well, passed in a
* register...
*/
DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
return (0);
}
argno -= (inreg + 1);
#endif
stack = (uintptr_t *)&fp[1];
load:
DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
val = stack[argno];
DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
return (val);
}
static dtrace_pops_t sdt_pops = {
NULL,
sdt_provide_module,
sdt_enable,
sdt_disable,
NULL,
NULL,
sdt_getargdesc,
sdt_getarg,
NULL,
sdt_destroy
};
/*ARGSUSED*/
static int
sdt_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
sdt_provider_t *prov;
if (ddi_create_minor_node(devi, "sdt", S_IFCHR,
0, DDI_PSEUDO, NULL) == DDI_FAILURE) {
cmn_err(CE_NOTE, "/dev/sdt couldn't create minor node");
ddi_remove_minor_node(devi, NULL);
return (DDI_FAILURE);
}
ddi_report_dev(devi);
sdt_devi = devi;
if (sdt_probetab_size == 0)
sdt_probetab_size = SDT_PROBETAB_SIZE;
sdt_probetab_mask = sdt_probetab_size - 1;
sdt_probetab =
kmem_zalloc(sdt_probetab_size * sizeof (sdt_probe_t *), KM_SLEEP);
dtrace_invop_add(sdt_invop);
for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) {
if (dtrace_register(prov->sdtp_name, prov->sdtp_attr,
DTRACE_PRIV_KERNEL, NULL,
&sdt_pops, prov, &prov->sdtp_id) != 0) {
cmn_err(CE_WARN, "failed to register sdt provider %s",
prov->sdtp_name);
}
}
return (DDI_SUCCESS);
}
/*ARGSUSED*/
static int
sdt_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
{
sdt_provider_t *prov;
switch (cmd) {
case DDI_DETACH:
break;
case DDI_SUSPEND:
return (DDI_SUCCESS);
default:
return (DDI_FAILURE);
}
for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) {
if (prov->sdtp_id != DTRACE_PROVNONE) {
if (dtrace_unregister(prov->sdtp_id) != 0)
return (DDI_FAILURE);
prov->sdtp_id = DTRACE_PROVNONE;
}
}
dtrace_invop_remove(sdt_invop);
kmem_free(sdt_probetab, sdt_probetab_size * sizeof (sdt_probe_t *));
return (DDI_SUCCESS);
}
/*ARGSUSED*/
static int
sdt_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
{
int error;
switch (infocmd) {
case DDI_INFO_DEVT2DEVINFO:
*result = (void *)sdt_devi;
error = DDI_SUCCESS;
break;
case DDI_INFO_DEVT2INSTANCE:
*result = (void *)0;
error = DDI_SUCCESS;
break;
default:
error = DDI_FAILURE;
}
return (error);
}
/*ARGSUSED*/
static int
sdt_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
{
return (0);
}
static struct cb_ops sdt_cb_ops = {
sdt_open, /* open */
nodev, /* close */
nulldev, /* strategy */
nulldev, /* print */
nodev, /* dump */
nodev, /* read */
nodev, /* write */
nodev, /* ioctl */
nodev, /* devmap */
nodev, /* mmap */
nodev, /* segmap */
nochpoll, /* poll */
ddi_prop_op, /* cb_prop_op */
0, /* streamtab */
D_NEW | D_MP /* Driver compatibility flag */
};
static struct dev_ops sdt_ops = {
DEVO_REV, /* devo_rev, */
0, /* refcnt */
sdt_info, /* get_dev_info */
nulldev, /* identify */
nulldev, /* probe */
sdt_attach, /* attach */
sdt_detach, /* detach */
nodev, /* reset */
&sdt_cb_ops, /* driver operations */
NULL, /* bus operations */
nodev, /* dev power */
ddi_quiesce_not_needed, /* quiesce */
};
/*
* Module linkage information for the kernel.
*/
static struct modldrv modldrv = {
&mod_driverops, /* module type (this is a pseudo driver) */
"Statically Defined Tracing", /* name of module */
&sdt_ops, /* driver ops */
};
static struct modlinkage modlinkage = {
MODREV_1,
(void *)&modldrv,
NULL
};
int
_init(void)
{
return (mod_install(&modlinkage));
}
int
_info(struct modinfo *modinfop)
{
return (mod_info(&modlinkage, modinfop));
}
int
_fini(void)
{
return (mod_remove(&modlinkage));
}