sdt: Add macros which expand to probe and provider structure names

No functional change intended.

MFC after: 1 week

netinet: add a probe point for IP, IP6, ICMP, ICMP6, UDP and TCP stats counters

When debugging network issues one common clue is an unexpectedly
incrementing error counter. This is helpful, in that

netinet: add a probe point for IP, IP6, ICMP, ICMP6, UDP and TCP stats counters

When debugging network issues one common clue is an unexpectedly
incrementing error counter. This is helpful, in that it gives us an
idea of what might be going wrong, but often these counters may be
incremented in different functions.

Add a static probe point for them so that we can use dtrace to get
futher information (e.g. a stack trace).

For example:
dtrace -n 'mib:ip:count: { printf("%d", arg0); stack(); }'

This can be disabled by setting the following kernel option:
options KDTRACE_NO_MIB_SDT

Reviewed by: gallatin, tuexen (previous version), gnn (previous version)
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D43504

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sdt: Use designated initializers for various definitions

No functional change intended.

MFC after: 1 week

sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

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sdt: add __sdt_used

To pacify set-but-not-used warns when compiling without sdt probes.

Reviewed by:
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision:

Provide SDT_PROBES_ENABLED for kernels without KDTRACE.

Sponsored by: The FreeBSD Foundation

Provide SDT_PROBES_ENABLED macro.

Sponsored by: The FreeBSD Foundation

sys/sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error

sys/sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

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sdt: make all sdt probe sites test one variable

This saves on cache misses at the expense of a slight grow of .text.

Note this is a bandaid for lack of hotpatching.

Discussed with: markj

sdt: whack unused SDT_PROBE_ENABLED

Implement LOCKSTAT_OOL_PROFILE_ENABLED

For use in uninlined locking primitives to decide whether lockstat
or profiling needs to be taken care of.

mtx: move lockstat handling out of inline primitives

Lockstat requires checking if it is enabled and if so, calling a 6 argument
function. Further, determining whether to call it on unlock requires

mtx: move lockstat handling out of inline primitives

Lockstat requires checking if it is enabled and if so, calling a 6 argument
function. Further, determining whether to call it on unlock requires
pre-reading the lock value.

This is problematic in at least 3 ways:
- more branches in the hot path than necessary
- additional cacheline ping pong under contention
- bigger code

Instead, check first if lockstat handling is necessary and if so, just fall
back to regular locking routines. For this purpose a new macro is introduced
(LOCKSTAT_PROFILE_ENABLED).

LOCK_PROFILING uninlines all primitives. Fold in the current inline lock
variant into the _mtx_lock_flags to retain the support. With this change
the inline variants are not used when LOCK_PROFILING is defined and thus
can ignore its existence.

This results in:
text data bss dec hex filename
22259667 1303208 4994976 28557851 1b3c21b kernel.orig
21797315 1303208 4994976 28095499 1acb40b kernel.patched

i.e. about 3% reduction in text size.

A remaining action is to remove spurious arguments for internal kernel
consumers.

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sdt: annotate the probe test as likely to fail

This saves a jump in plenty of cases.

Approved by: re (kib)
MFC after: 1 week

sdt.h: no need for argtype_list_head

MFC after: 12 days

Define _DTRACE_VERSION in sdt.h rather than setting it manually. This is
similar to what illumos does, and makes it easier to enable USDT probes
in third-party software that doesn't make use of the s

Define _DTRACE_VERSION in sdt.h rather than setting it manually. This is
similar to what illumos does, and makes it easier to enable USDT probes
in third-party software that doesn't make use of the system makefiles.

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Remove _DTRACE_VERSION from sdt.h. It will now come from the command line
(bsd.dep.mk).

MFC after: 3 weeks

sdt: add support for solaris/illumos style DTRACE_PROBE macros

The new macros are implemented in terms of SDT_PROBE_DEFINE and SDT_PROBE.
Probes defined in this way will appear under SDT provider na

sdt: add support for solaris/illumos style DTRACE_PROBE macros

The new macros are implemented in terms of SDT_PROBE_DEFINE and SDT_PROBE.
Probes defined in this way will appear under SDT provider named "sdt".
Parameter types are exposed via SDT_PROBE_ARGTYPE.
This is something that illumos does not have by default.

This kind of SDT probes is already present in ZFS code, so those probes
will now be available if KDTRACE_HOOKS options is enabled.

A potential future illumos compatibility enhancement is to encode a provider
name as a prefix in a probe name.

Reviewed by: markj
MFC after: 3 weeks
X-MFC after: r258622

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dtrace sdt: remove the ugly sname parameter of SDT_PROBE_DEFINE

In its stead use the Solaris / illumos approach of emulating '-' (dash)
in probe names with '__' (two consecutive underscores).

Revie

dtrace sdt: remove the ugly sname parameter of SDT_PROBE_DEFINE

In its stead use the Solaris / illumos approach of emulating '-' (dash)
in probe names with '__' (two consecutive underscores).

Reviewed by: markj
MFC after: 3 weeks

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Do some cleanup of the SDT code. In particular,

* Remove the unused sdt cdev.
* Don't bother keeping a list of probes in struct sdt_prov; it's not needed.
* Invoke sdt_load and sdt_unload from the m

Do some cleanup of the SDT code. In particular,

* Remove the unused sdt cdev.
* Don't bother keeping a list of probes in struct sdt_prov; it's not needed.
* Invoke sdt_load and sdt_unload from the module handler instead of
registering separate SYSINITs.
* Keep to within 80 columns.
* Check for errors from dtrace_unregister().

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Give argtype struct names a different prefix than probe struct names.
Otherwise it's possible to declare SDT probes in such a way that a name
collision occurs, causing an unexpected compilation error

Give argtype struct names a different prefix than probe struct names.
Otherwise it's possible to declare SDT probes in such a way that a name
collision occurs, causing an unexpected compilation error.

Approved by: re (gjb)
MFC after: 1 week

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Add a "translated type" argument to SDT_PROBE_ARGTYPE() and add some macros
which allow one to define SDT probes that specify translated types. The idea
is to make it easy to write SDT probe definiti

Add a "translated type" argument to SDT_PROBE_ARGTYPE() and add some macros
which allow one to define SDT probes that specify translated types. The idea
is to make it easy to write SDT probe definitions that can work across
multiple operating systems. In particular, this makes it possible to port
illumos SDT probes to FreeBSD without changing their argument types, so long
as the appropriate translators are defined. Then DTrace scripts written for
Solaris/illumos will work on FreeBSD without any changes.

MFC after: 1 week

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FreeBSD's DTrace implementation has a few problems with respect to handling
probes declared in a kernel module when that module is unloaded. In
particular,

* Unloading a module with active SDT probe

FreeBSD's DTrace implementation has a few problems with respect to handling
probes declared in a kernel module when that module is unloaded. In
particular,

* Unloading a module with active SDT probes will cause a panic. [1]
* A module's (FBT/SDT) probes aren't destroyed when the module is unloaded;
trying to use them after the fact will generally cause a panic.

This change fixes both problems by porting the DTrace module load/unload
handlers from illumos and registering them with the corresponding
EVENTHANDLER(9) handlers. This allows the DTrace framework to destroy all
probes defined in a module when that module is unloaded, and to prevent a
module unload from proceeding if some of its probes are active. The latter
problem has already been fixed for FBT probes by checking lf->nenabled in
kern_kldunload(), but moving the check into the DTrace framework generalizes
it to all kernel providers and also fixes a race in the current
implementation (since a probe may be activated between the check and the
call to linker_file_unload()).

Additionally, the SDT implementation has been reworked to define SDT
providers/probes/argtypes in linker sets rather than using SYSINIT/SYSUNINIT
to create and destroy SDT probes when a module is loaded or unloaded. This
simplifies things quite a bit since it means that pretty much all of the SDT
code can live in sdt.ko, and since it becomes easier to integrate SDT with
the DTrace framework. Furthermore, this allows FreeBSD to be quite flexible
in that SDT providers spanning multiple modules can be created on the fly
when a module is loaded; at the moment it looks like illumos' SDT
implementation requires all SDT probes to be statically defined in a single
kernel table.

PR: 166927, 166926, 166928
Reported by: davide [1]
Reviewed by: avg, trociny (earlier version)
MFC after: 1 month

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Also define SDT_PROBE_DEFINE0 for the !KDTRACE_HOOKS case.

Add SDT_PROBE_DEFINE0 for consistency with SDT_PROBE0.

MFC after: 1 week