fbt.c

Sun Solaris 10 中的 DTrace 组件的源代码。请参看: http://www.sun.com/software/solaris/observability.jsp

			cmn_err(CE_NOTE, "cannot instrument %s: "
			    "save not in first basic block", name);
			continue;
		}

		if (instr == limit) {
			if (!have_ctf)
				continue;
			is_leaf = 1;

			if (!estimate)
				fbt_leaf_functions++;

			canpatch = fbt_canpatch_retl;
			patch = fbt_patch_retl;
		} else {
			canpatch = fbt_canpatch_return;
			patch = fbt_patch_return;
		}

		if (!have_ctf && !is_leaf) {
			/*
			 * Before we assume that this isn't something tricky,
			 * look for other saves.  If we find them, there are
			 * multiple entry points here (or something), and we'll
			 * leave it alone.
			 */
			while (++instr < limit) {
				if (FBT_IS_SAVE(*instr))
					break;
			}

			if (instr != limit)
				continue;
		}

		instr = base;

		if (estimate) {
			tramp.fbtt_next = (uintptr_t)faketramp;
			tramp.fbtt_limit = tramp.fbtt_next + sizeof (faketramp);
			(void) fbt_patch_entry(instr, FBT_ESTIMATE_ID,
			    &tramp, nargs);
			fbt_size += tramp.fbtt_next - (uintptr_t)faketramp;
		} else {
			fbt = kmem_zalloc(sizeof (fbt_probe_t), KM_SLEEP);
			fbt->fbtp_name = name;
			fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
			    name, FBT_ENTRY, 1, fbt);
			fbt->fbtp_patchval = FBT_BAA(instr, tramp.fbtt_va);

			if (!fbt_patch_entry(instr, fbt->fbtp_id,
			    &tramp, nargs)) {
				cmn_err(CE_WARN, "unexpectedly short FBT table "
				    "in module %s (sym %d of %d)", modname,
				    i, nsyms);
				break;
			}

			fbt->fbtp_patchpoint =
			    (uint32_t *)((uintptr_t)mp->textwin +
			    ((uintptr_t)instr - (uintptr_t)mp->text));
			fbt->fbtp_savedval = *instr;

			fbt->fbtp_ctl = ctl;
			fbt->fbtp_loadcnt = ctl->mod_loadcnt;
			fbt->fbtp_primary = primary;
			fbt->fbtp_symndx = i;
			mp->fbt_nentries++;
		}

		retfbt = NULL;
again:
		if (++instr == limit)
			continue;

		offset = (uintptr_t)instr - (uintptr_t)base;

		if (!(*canpatch)(instr, offset))
			goto again;

		if (estimate) {
			tramp.fbtt_next = (uintptr_t)faketramp;
			tramp.fbtt_limit = tramp.fbtt_next + sizeof (faketramp);
			(void) (*patch)(instr, base, limit,
			    offset, FBT_ESTIMATE_ID, &tramp);
			fbt_size += tramp.fbtt_next - (uintptr_t)faketramp;

			goto again;
		}

		fbt = kmem_zalloc(sizeof (fbt_probe_t), KM_SLEEP);
		fbt->fbtp_name = name;

		if (retfbt == NULL) {
			fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
			    name, FBT_RETURN, 1, fbt);
		} else {
			retfbt->fbtp_next = fbt;
			fbt->fbtp_id = retfbt->fbtp_id;
		}

		fbt->fbtp_return = 1;
		retfbt = fbt;

		if ((fbt->fbtp_patchval = (*patch)(instr, base, limit, offset,
		    fbt->fbtp_id, &tramp)) == FBT_ILLTRAP) {
			cmn_err(CE_WARN, "unexpectedly short FBT table "
			    "in module %s (sym %d of %d)", modname, i, nsyms);
			break;
		}

		fbt->fbtp_patchpoint = (uint32_t *)((uintptr_t)mp->textwin +
		    ((uintptr_t)instr - (uintptr_t)mp->text));
		fbt->fbtp_savedval = *instr;
		fbt->fbtp_ctl = ctl;
		fbt->fbtp_loadcnt = ctl->mod_loadcnt;
		fbt->fbtp_primary = primary;
		fbt->fbtp_symndx = i;
		mp->fbt_nentries++;

		goto again;
	}

	if (estimate) {
		/*
		 * Slosh on another entry's worth...
		 */
		fbt_size += FBT_ENT_MAXSIZE;
		mp->fbt_size = fbt_size;
		mp->fbt_tab = kobj_texthole_alloc(mp->text, fbt_size);

		if (mp->fbt_tab == NULL) {
			cmn_err(CE_WARN, "couldn't allocate FBT table "
			    "for module %s", modname);
		} else {
			estimate = 0;
			goto forreal;
		}
	} else {
		fbt_trampoline_unmap();
	}

error:
	if (fp != NULL)
		ctf_close(fp);
}

/*ARGSUSED*/
static void
fbt_destroy(void *arg, dtrace_id_t id, void *parg)
{
	fbt_probe_t *fbt = parg, *next;
	struct modctl *ctl = fbt->fbtp_ctl;

	do {
		if (ctl != NULL && ctl->mod_loadcnt == fbt->fbtp_loadcnt) {
			if ((ctl->mod_loadcnt == fbt->fbtp_loadcnt &&
			    ctl->mod_loaded) || fbt->fbtp_primary) {
				((struct module *)
				    (ctl->mod_mp))->fbt_nentries--;
			}
		}

		next = fbt->fbtp_next;
		kmem_free(fbt, sizeof (fbt_probe_t));
		fbt = next;
	} while (fbt != NULL);
}

/*ARGSUSED*/
static void
fbt_enable(void *arg, dtrace_id_t id, void *parg)
{
	fbt_probe_t *fbt = parg, *f;
	struct modctl *ctl = fbt->fbtp_ctl;

	ctl->mod_nenabled++;

	for (f = fbt; f != NULL; f = f->fbtp_next) {
		if (f->fbtp_patchpoint == NULL) {
			/*
			 * Due to a shortened FBT table, this entry was never
			 * completed; refuse to enable it.
			 */
			if (fbt_verbose) {
				cmn_err(CE_NOTE, "fbt is failing for probe %s "
				    "(short FBT table in %s)",
				    fbt->fbtp_name, ctl->mod_modname);
			}

			return;
		}
	}

	/*
	 * If this module has disappeared since we discovered its probes,
	 * refuse to enable it.
	 */
	if (!fbt->fbtp_primary && !ctl->mod_loaded) {
		if (fbt_verbose) {
			cmn_err(CE_NOTE, "fbt is failing for probe %s "
			    "(module %s unloaded)",
			    fbt->fbtp_name, ctl->mod_modname);
		}

		return;
	}

	/*
	 * 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 != fbt->fbtp_loadcnt) {
		if (fbt_verbose) {
			cmn_err(CE_NOTE, "fbt is failing for probe %s "
			    "(module %s reloaded)",
			    fbt->fbtp_name, ctl->mod_modname);
		}

		return;
	}

	for (; fbt != NULL; fbt = fbt->fbtp_next)
		*fbt->fbtp_patchpoint = fbt->fbtp_patchval;
}

/*ARGSUSED*/
static void
fbt_disable(void *arg, dtrace_id_t id, void *parg)
{
	fbt_probe_t *fbt = parg, *f;
	struct modctl *ctl = fbt->fbtp_ctl;

	ASSERT(ctl->mod_nenabled > 0);
	ctl->mod_nenabled--;

	for (f = fbt; f != NULL; f = f->fbtp_next) {
		if (f->fbtp_patchpoint == NULL)
			return;
	}

	if ((!fbt->fbtp_primary && !ctl->mod_loaded) ||
	    (ctl->mod_loadcnt != fbt->fbtp_loadcnt))
		return;

	for (; fbt != NULL; fbt = fbt->fbtp_next)
		*fbt->fbtp_patchpoint = fbt->fbtp_savedval;
}

/*ARGSUSED*/
static void
fbt_suspend(void *arg, dtrace_id_t id, void *parg)
{
	fbt_probe_t *fbt = parg;
	struct modctl *ctl = fbt->fbtp_ctl;

	if (!fbt->fbtp_primary && !ctl->mod_loaded)
		return;

	if (ctl->mod_loadcnt != fbt->fbtp_loadcnt)
		return;

	ASSERT(ctl->mod_nenabled > 0);

	for (; fbt != NULL; fbt = fbt->fbtp_next)
		*fbt->fbtp_patchpoint = fbt->fbtp_savedval;
}

/*ARGSUSED*/
static void
fbt_resume(void *arg, dtrace_id_t id, void *parg)
{
	fbt_probe_t *fbt = parg;
	struct modctl *ctl = fbt->fbtp_ctl;

	if (!fbt->fbtp_primary && !ctl->mod_loaded)
		return;

	if (ctl->mod_loadcnt != fbt->fbtp_loadcnt)
		return;

	ASSERT(ctl->mod_nenabled > 0);

	for (; fbt != NULL; fbt = fbt->fbtp_next)
		*fbt->fbtp_patchpoint = fbt->fbtp_patchval;
}

/*ARGSUSED*/
static void
fbt_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
{
	fbt_probe_t *fbt = parg;
	struct modctl *ctl = fbt->fbtp_ctl;
	struct module *mp = ctl->mod_mp;
	ctf_file_t *fp = NULL, *pfp;
	ctf_funcinfo_t f;
	int error;
	ctf_id_t argv[32], type;
	int argc = sizeof (argv) / sizeof (ctf_id_t);
	const char *parent;

	if (!ctl->mod_loaded || (ctl->mod_loadcnt != fbt->fbtp_loadcnt))
		goto err;

	if (fbt->fbtp_return && desc->dtargd_ndx == 0) {
		(void) strcpy(desc->dtargd_native, "int");
		return;
	}

	if ((fp = ctf_modopen(mp, &error)) == NULL) {
		/*
		 * We have no CTF information for this module -- and therefore
		 * no args[] information.
		 */
		goto err;
	}

	/*
	 * If we have a parent container, we must manually import it.
	 */
	if ((parent = ctf_parent_name(fp)) != NULL) {
		struct modctl *mod;

		/*
		 * We must iterate over all modules to find the module that
		 * is our parent.
		 */
		for (mod = &modules; mod != NULL; mod = mod->mod_next) {
			if (strcmp(mod->mod_filename, parent) == 0)
				break;
		}

		if (mod == NULL)
			goto err;

		if ((pfp = ctf_modopen(mod->mod_mp, &error)) == NULL)
			goto err;

		if (ctf_import(fp, pfp) != 0) {
			ctf_close(pfp);
			goto err;
		}

		ctf_close(pfp);
	}

	if (ctf_func_info(fp, fbt->fbtp_symndx, &f) == CTF_ERR)
		goto err;

	if (fbt->fbtp_return) {
		if (desc->dtargd_ndx > 1)
			goto err;

		ASSERT(desc->dtargd_ndx == 1);
		type = f.ctc_return;
	} else {
		if (desc->dtargd_ndx + 1 > f.ctc_argc)
			goto err;

		if (ctf_func_args(fp, fbt->fbtp_symndx, argc, argv) == CTF_ERR)
			goto err;

		type = argv[desc->dtargd_ndx];
	}

	if (ctf_type_name(fp, type, desc->dtargd_native,
	    DTRACE_ARGTYPELEN) != NULL) {
		ctf_close(fp);
		return;
	}
err:
	if (fp != NULL)
		ctf_close(fp);

	desc->dtargd_ndx = DTRACE_ARGNONE;
}

static dtrace_pattr_t fbt_attr = {
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
};

static dtrace_pops_t fbt_pops = {
	NULL,
	fbt_provide_module,
	fbt_enable,
	fbt_disable,
	fbt_suspend,
	fbt_resume,
	fbt_getargdesc,
	NULL,
	NULL,
	fbt_destroy
};

static int
fbt_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
	switch (cmd) {
	case DDI_ATTACH:
		break;
	case DDI_RESUME:
		return (DDI_SUCCESS);
	default:
		return (DDI_FAILURE);
	}

	if (ddi_create_minor_node(devi, "fbt", S_IFCHR, 0,
	    DDI_PSEUDO, NULL) == DDI_FAILURE ||
	    dtrace_register("fbt", &fbt_attr, DTRACE_PRIV_KERNEL, 0,
	    &fbt_pops, NULL, &fbt_id) != 0) {
		ddi_remove_minor_node(devi, NULL);
		return (DDI_FAILURE);
	}

	ddi_report_dev(devi);
	fbt_devi = devi;
	return (DDI_SUCCESS);
}

static int
fbt_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
	switch (cmd) {
	case DDI_DETACH:
		break;
	case DDI_SUSPEND:
		return (DDI_SUCCESS);
	default:
		return (DDI_FAILURE);
	}

	if (dtrace_unregister(fbt_id) != 0)
		return (DDI_FAILURE);

	ddi_remove_minor_node(devi, NULL);
	return (DDI_SUCCESS);
}

/*ARGSUSED*/
static int
fbt_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
{
	int error;

	switch (infocmd) {
	case DDI_INFO_DEVT2DEVINFO:
		*result = (void *)fbt_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
fbt_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
{
	return (0);
}

static struct cb_ops fbt_cb_ops = {
	fbt_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 fbt_ops = {
	DEVO_REV,		/* devo_rev */
	0,			/* refcnt */
	fbt_info,		/* get_dev_info */
	nulldev,		/* identify */
	nulldev,		/* probe */
	fbt_attach,		/* attach */
	fbt_detach,		/* detach */
	nodev,			/* reset */
	&fbt_cb_ops,		/* driver operations */
	NULL,			/* bus operations */
	nodev			/* dev power */
};

/*
 * Module linkage information for the kernel.
 */
static struct modldrv modldrv = {
	&mod_driverops,		/* module type (this is a pseudo driver) */
	"Function Boundary Tracing",	/* name of module */
	&fbt_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));
}