- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Initialize and free the DTrace taskqueue in the dtrace module load/unload
handlers rather than in the dtrace device open/close methods. The current
approach can cause a panic if the device is closed which the taskqueue
thread is active, or if a kernel module containing a provider is unloaded
while retained enablings are present and the dtrace device isn't opened.

Submitted by: gibbs (original version)
Reviewed by: gibbs
Approved by: re (glebius)
MFC after: 2 weeks

- Use make_dev_credf(MAKEDEV_REF) instead of the race-prone make_dev()+
dev_ref() in the clone handlers that still use it.
- Don't set SI_CHEAPCLONE flag, it's not used anywhere neither in devfs
(for anything real)

Reviewed by: kib

Whitespace cleanup.

Fixes for DTrace on PowerPC:

- Implement dtrace_getarg()
- Sync fbt with x86, and fix a typo.
- Pull in the time synchronization code from amd64.

Rename the kld_unload event handler to kld_unload_try, and add a new
kld_unload event handler which gets invoked after a linker file has been
successfully unloaded. The kld_unload and kld_load event handlers are now
invoked with the shared linker lock held, while kld_unload_try is invoked
with the lock exclusively held.

Convert hwpmc(4) to use these event handlers instead of having
kern_kldload() and kern_kldunload() invoke hwpmc(4) hooks whenever files are
loaded or unloaded. This has no functional effect, but simplifes the linker
code somewhat.

Reviewed by: jhb

Make dtrace_copy() actually work on PowerPC. Although unused currently,
it may be used in the future by dtrace.

Fix some ppc64 dtrace bugs, and enable systrace_freebsd32 for ppc64.

Use kld_{load,unload} instead of mod_{load,unload} for the linker file load
and unload event handlers added in r254266.

Reported by: jhb
X-MFC with: r254266

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

opensolaris code: translate INVARIANTS to DEBUG and ZFS_DEBUG

Do this by forcing inclusion of
sys/cddl/compat/opensolaris/sys/debug_compat.h
via -include option into all source files from OpenSolaris.
Note that this -include option must always be after -include opt_global.h.

Additionally, remove forced definition of DEBUG for some modules and fix
their build without DEBUG.

Also, meaning of DEBUG was overloaded to enable WITNESS support for some
OpenSolaris (primarily ZFS) locks. Now this overloading is removed and
that use of DEBUG is replaced with a new option OPENSOLARIS_WITNESS.

MFC after: 17 days

dtrace disassembler: take the latest/last CDDL code from OpenSolaris

OpenSolaris version is:
13108:33bb8a0301ab
6762020 Disassembly support for Intel Advanced Vector Extensions (AVX)

This corresponds to Illumos-gate (github) version
ab47273fedff893c8ae22ec39ffc666d4fa6fc8b

MFC after: 3 weeks

Hide references to mod_lock. In FreeBSD it is always acquired with the
provider lock held, so its use has no effect.

SDT probes can directly pass up to five arguments as arguments to
dtrace_probe(). Arguments beyond these five must be obtained in an
architecture-specific way; this can be done through the getargval provider
method, and through dtrace_getarg() if getargval isn't overridden.

This change fixes two off-by-one bugs in the way these arguments are fetched
in FreeBSD's DTrace implementation. First, the SDT provider must set the
aframes parameter to 1 when creating a probe. The aframes parameter controls
the number of frames that dtrace_getarg() will step over in order to find
the frame containing the extra arguments. On FreeBSD, dtrace_getarg() is
called in SDT probe context via

dtrace_probe()->dtrace_dif_emulate()->dtrace_dif_variable->dtrace_getarg()

so aframes must be 3 since the arguments are in dtrace_probe()'s frame; it
was previously being called with a value of 2 instead. illumos uses a
different aframes value for SDT probes, but this is because illumos SDT
probes fire by triggering the #UD fault handler rather than calling
dtrace_probe() directly.

The second bug has to do with the way arguments are grabbed out
dtrace_probe()'s frame on amd64. The code currently jumps over the first
stack argument and retrieves the rest of them using a pointer into the
stack. This works on i386 because all of dtrace_probe()'s arguments will be
on the stack and the first argument is the probe ID, which should be
ignored. However, it is incorrect to ignore the first stack argument on
amd64, so we correct the pointer used to access the arguments.

MFC after: 2 weeks

Port the SDT test now that it's possible to create SDT probes that take
seven arguments.

The original test uses Solaris' uadmin system call to trigger the test
probe; this change adds a sysctl to the dtrace_test module and gets the test
program to trigger the test probe via the sysctl handler.

The test is currently failing on amd64 because of some bugs in the way that
probe arguments beyond the first five are obtained - these bugs will be
fixed in a separate change.

Bring back part of r249367 by adding DTrace's temporal option, which allows
users to guarantee that the output of DTrace scripts will be time-ordered.
This option is enabled by adding the line

#pragma D option temporal

to the beginning of a script, or by adding '-x temporal' to the arguments of
dtrace(1).

This change fixes a bug in the original port of the temporal option. This
bug was causing some assertions to fail, so they had been disabled; in this
revision the assertions are working properly and are enabled.

The DTrace version number has been bumped from 1.9.0 to 1.9.1 to reflect
the language change that's being introduced.

This change corresponds to part of illumos-gate commit e5803b76927480:
3021 option for time-ordered output from dtrace(1M)

Reviewed by: pfg
Obtained from: illumos
MFC after: 1 month

Add FBT for PowerPC DTrace. Also, clean up the DTrace assembly code,
much of which is not necessary for PowerPC.

The FBT module can likely be factored into 3 separate files: common,
intel, and powerpc, rather than duplicating most of the code between
the x86 and PowerPC flavors.

All DTrace modules for PowerPC will be MFC'd together once Fasttrap is
completed.

Fix warning: comparison of unsigned expression < 0 is always false.

Reported by: clang

Fix the PowerPC DTrace copy functions. The kernel doesn't hold the same view to
the user map, so use the md copy in/out functions provided by the kernel.

MFC with: r242723

Correct a series of errors in the hand-rolled locking for drace_debug.c:

- Use spinlock_enter()/spinlock_exit() to prevent a thread holding a
debug lock from being preempted to prevent other threads waiting
on that lock from starvation.

- Handle the possibility of CPU migration in between the fetch of curcpu
and the call to spinlock_enter() by saving curcpu in a local variable.

- Use memory barriers to prevent reordering of loads and stores of the
data protected by the lock outside of the critical section

- Eliminate false sharing of the locks by moving them into the structures
that they protect and aligning them to a cacheline boundary.

- Record the owning thread in the lock to make debugging future problems
easier.

Reviewed by: rpaulo (initial version)
MFC after: 2 weeks

Implement DTrace for PowerPC. This includes both 32-bit and 64-bit.

There is one known issue: Some probes will display an error message along the
lines of: "Invalid address (0)"

I tested this with both a simple dtrace probe and dtruss on a few different
binaries on 32-bit. I only compiled 64-bit, did not run it, but I don't expect
problems without the modules loaded. Volunteers are welcome.

MFC after: 1 month

Change UL to ULL since time is 32 bits.

Pointed out by: avg@
MFC after: 2 weeks

Add support for walltimestamp in DTrace.

Submitted by: Fabian Keil
MFC after: 2 weeks

r237748 continuation: fix nopw (0f 1f) behavior with respect to modifiers

To do: proper merge with Illumos vendor area.

Reported by: emaste
Tested by: emaste
Obtained from: Illumos commit 13442:4adbe6de60c8
MFC after: 5 days

r237748 continuation: segment-override prefixes are not invalid in long mode

Update DTrace disassembler accordingly. The code to treat the prefixes
as null prefixes was already in place.
Although in practice compilers seem to generate only cs-prefix for use
in long NOPs, the same treatment is applied to all of cs, ds, es, ss for
consistency.

Reported by: emaste
Tested by: emaste
Obtained from: Illumos commit 13442:4adbe6de60c8 (+ local changes)
MFC after: 5 days

dtrace instruction decoder: add 0x0f 0x1f NOP opcode support

According to the AMD manual the whole range from 0x09 to 0x1f are NOPs.
Intel manual mentions only 0x1f. Use only Intel one for now, it seems
to be the one actually generated by compilers.
Use gdb mnemonic for the operation: "nopw".

[1] AMD64 Architecture Programmer's Manual
Volume 3: General-Purpose and System Instructions
[2] Software Optimization Guide for AMD Family 10h Processors
[3] Intel(R) 64 and IA-32 Architectures Software Developer’s Manual
Volume 2 (2A, 2B & 2C): Instruction Set Reference, A-Z

Tested by: Fabian Keil <freebsd-listen@fabiankeil.de> (earlier version)
MFC after: 3 days

Integrate a fix for a very odd signal delivery problem found
by Bryan Cantril and others in the Solaris/Illumos version of DTrace.

Obtained from: https://www.illumos.org/issues/789
MFC after: 2 weeks

Fix DTrace TSC skew calculation:

The skew calculation here is exactly backwards. We were able to repro
it on a multi-package ESX server running a FreeBSD VM, where the TSCs
can be pretty evil.

MFC after: 1 week

Submitted by: Jeff Ford <jeffrey.ford2@isilon.com>
Reviewed by: avg, gnn

- For o32 ABI get arguments from the stack
- Clear CPU_DTRACE_FAULT flag in userland backtrace routine. It just
means we hit wrong memory region and should stop.

Properly cast 64-bit dofhp_dof to pointer.

For i386 this change is no-op. For AMD64 it was tested with DTrace test
suite: results are the same from the test run before the change and after

Use macroses to load/store pointers and increase indexes instead of
hardcoded MIPS64 instructions

Add device part of DTrace/MIPS code

On i386, fbt probes are implemented by writing an invalid opcode over
certain instructions in a function prologue or epilogue. DTrace has a
hook into the invalid opcode fault handler that checks whether the fault
was due to an probe and if so, runs the DTrace magic.

Upon returning from an invalid opcode fault caused by a probe, DTrace must
emulate the instruction that was replaced with the invalid opcode and then
return control to the instruction following the invalid opcode.

There were a pair of related bugs in the emulation for the leave
instruction. The leave instruction is used to pop off a stack frame prior
to returning from a function. The emulation for this instruction must
move the trap frame for the invalid opcode fault down the stack to the
bottom of the stack frame that is being removed, and then execute an iret.

At two points in this process, the emulation code was storing values above
the current value of the stack pointer. This opened up a window in which
if we were two take an interrupt, the trap frame for the interrupt would
overwrite the values stored on the stack, causing the system to panic
later.

The first bug was that at one point the emulation code saves the new value
for $esp above the current stack pointer value. The fix is to save this
value instead inside of the original trap frame. At this point we do
not need the original trap frame so this is safe.

The second bug is that when the emulate code loads $esp from the stack, it
points part-way through the new trap frame instead of at its beginning.
The emulation code adjusts the stack pointer to the correct value
immediately afterwards, but this still leaves a one instruction window in
which an interrupt would corrupt this trap frame. Fix this by adjusting
the stack frame value before loading it into $esp.

This fixes panics in invop_leave on i386 when using fbt return probes.

Reviewed by: rpaulo, attilio
MFC after: 1 week

Define dtrace_cmpset_long in terms of atomic_cmpset_long
and not by virtue of inline assembly. Now this file
compiles on all supported architectures.

With retirement of cpumask_t and usage of cpuset_t for representing a
mask of CPUs, pc_other_cpus and pc_cpumask become highly inefficient.

Remove them and replace their usage with custom pc_cpuid magic (as,
atm, pc_cpumask can be easilly represented by (1 << pc_cpuid) and
pc_other_cpus by (all_cpus & ~(1 << pc_cpuid))).

This change is not targeted for MFC because of struct pcpu members
removal and dependency by cpumask_t retirement.

MD review by: marcel, marius, alc
Tested by: pluknet
MD testing by: marcel, marius, gonzo, andreast

etire the cpumask_t type and replace it with cpuset_t usage.

This is intended to fix the bug where cpu mask objects are
capped to 32. MAXCPU, then, can now arbitrarely bumped to whatever
value. Anyway, as long as several structures in the kernel are
statically allocated and sized as MAXCPU, it is suggested to keep it
as low as possible for the time being.

Technical notes on this commit itself:
- More functions to handle with cpuset_t objects are introduced.
The most notable are cpusetobj_ffs() (which calculates a ffs(3)
for a cpuset_t object), cpusetobj_strprint() (which prepares a string
representing a cpuset_t object) and cpusetobj_strscan() (which
creates a valid cpuset_t starting from a string representation).
- pc_cpumask and pc_other_cpus are target to be removed soon.
With the moving from cpumask_t to cpuset_t they are now inefficient
and not really useful. Anyway, for the time being, please note that
access to pcpu datas is protected by sched_pin() in order to avoid
migrating the CPU while reading more than one (possible) word
- Please note that size of cpuset_t objects may differ between kernel
and userland. While this is not directly related to the patch itself,
it is good to understand that concept and possibly use the patch
as a reference on how to deal with cpuset_t objects in userland, when
accessing kernland members.
- KTR_CPUMASK is changed and now is represented through a string, to be
set as the example reported in NOTES.

Please additively note that no MAXCPU is bumped in this patch, but
private testing has been done until to MAXCPU=128 on a real 8x8x2(htt)
machine (amd64).

Please note that the FreeBSD version is not yet bumped because of
the upcoming pcpu changes. However, note that this patch is not
targeted for MFC.

People to thank for the time spent on this patch:
- sbruno, pluknet and Nicholas Esborn (nick AT desert DOT net) tested
several revision of the patches and really helped in improving
stability of this work.
- marius fixed several bugs in the sparc64 implementation and reviewed
patches related to ktr.
- jeff and jhb discussed the basic approach followed.
- kib and marcel made targeted review on some specific part of the
patch.
- marius, art, nwhitehorn and andreast reviewed MD specific part of
the patch.
- marius, andreast, gonzo, nwhitehorn and jceel tested MD specific
implementations of the patch.
- Other people have made contributions on other patches that have been
already committed and have been listed separately.

Companies that should be mentioned for having participated at several
degrees:
- Yahoo! for having offered the machines used for testing on big
count of CPUs.
- The FreeBSD Foundation for having sponsored my devsummit attendance,
which has been instrumental.
- Sandvine for having offered offices and infrastructure during
development.

(I really hope I didn't forget anyone, if it happened I apologize in
advance).

dtrace: remove unused code

Which is also useless, IMO.

MFC after: 5 days

Use atomic load & store for TSC frequency. It may be overkill for amd64 but
safer for i386 because it can be easily over 4 GHz now. More worse, it can
be easily changed by user with 'machdep.tsc_freq' tunable (directly) or
cpufreq(4) (indirectly). Note it is intentionally not used in performance
critical paths to avoid performance regression (but we should, in theory).
Alternatively, we may add "virtual TSC" with lower frequency if maximum
frequency overflows 32 bits (and ignore possible incoherency as we do now).

Fix typos - remove duplicate "the".

PR: bin/154928
Submitted by: Eitan Adler <lists at eitanadler.com>
MFC after: 3 days

dtrace_xcall: no need for special handling of curcpu

smp_rendezvous_cpus alreadt does the right thing in a very similar
fashion, so the code was kind of duplicating that.

MFC after: 3 weeks

dtrace_gethrtime_init: pin to master while examining other CPUs

Also use pc_cpumask to be future-friendly.

Reviewed by: jhb
MFC after: 2 weeks

Make the /dev/dtrace/helper node have the mode 0660. This allows
programs that refuse to run as root (pgsql) to install probes when their
user is part of the wheel group.

Sponsored by: The FreeBSD Foundation
> Description of fields to fill in above: 76 columns --|
> PR: If a GNATS PR is affected by the change.
> Submitted by: If someone else sent in the change.
> Reviewed by: If someone else reviewed your modification.
> Approved by: If you needed approval for this commit.
> Obtained from: If the change is from a third party.
> MFC after: N [day[s]|week[s]|month[s]]. Request a reminder email.
> Security: Vulnerability reference (one per line) or description.
> Empty fields above will be automatically removed.

M dev/dtrace/dtrace_load.c

Destroy the helper device when unloading.

Sponsored by: The FreeBSD Foundation

Add more compatibility structure members needed by the upcoming fasttrap
DTrace device.

Sponsored by: The FreeBSD Foundation

Kernel DTrace support for:
o uregs (sson@)
o ustack (sson@)
o /dev/dtrace/helper device (needed for USDT probes)

The work done by me was:
Sponsored by: The FreeBSD Foundation

Add a function compatibility function dtrace_instr_size_isa() that on
FreeBSD does the same as dtrace_dis_isize().

Sponsored by: The FreeBSD Foundation

Update several places that iterate over CPUs to use CPU_FOREACH().

dtrace_gethrtime: improve scaling of TSC ticks to nanoseconds

Currently dtrace_gethrtime uses formula similar to the following for
converting TSC ticks to nanoseconds:
rdtsc() * 10^9 / tsc_freq
The dividend overflows 64-bit type and wraps-around every 2^64/10^9 =
18446744073 ticks which is just a few seconds on modern machines.

Now we instead use precalculated scaling factor of
10^9*2^N/tsc_freq < 2^32 and perform TSC value multiplication separately
for each 32-bit half. This allows to avoid overflow of the dividend
described above.
The idea is taken from OpenSolaris.
This has an added feature of always scaling TSC with invariant value
regardless of TSC frequency changes. Thus the timestamps will not be
accurate if TSC actually changes, but they are always proportional to
TSC ticks and thus monotonic. This should be much better than current
formula which produces wildly different non-monotonic results on when
tsc_freq changes.

Also drop write-only 'cp' variable from amd64 dtrace_gethrtime_init()
to make it identical to the i386 twin.

PR: kern/127441
Tested by: Thomas Backman <serenity@exscape.org>
Reviewed by: jhb
Discussed with: current@, bde, gnn
Silence from: jb
Approved by: re (gnn)
MFC after: 1 week

dtrace/amd64: fix virtual address checks

On amd64 KERNBASE/kernbase does not mean start of kernel memory.
This should fix a KASSERT panic in dtrace_copycheck when copyin*()
is used in D program.
Also make checks for user memory a bit stricter.

Reported by: Thomas Backman <serenity@exscape.org>
Submitted by: wxs (kaddr part)
Tested by: Thomas Backman (prototype), wxs
Reviewed by: alc (concept), jhb, current@
Aprroved by: jb (concept)
MFC after: 2 weeks
PR: kern/134408

Remove unused variable.

Found with: Coverity Prevent(tm)
CID: 3669,3671

Approved by: jb

Merge latest DTrace changes from Perforce.

Remove unit2minor() use from kernel code.

When I changed kern_conf.c three months ago I made device unit numbers
equal to (unneeded) device minor numbers. We used to require
bitshifting, because there were eight bits in the middle that were
reserved for a device major number. Not very long after I turned
dev2unit(), minor(), unit2minor() and minor2unit() into macro's.
The unit2minor() and minor2unit() macro's were no-ops.

We'd better not remove these four macro's from the kernel, because there
is a lot of (external) code that may still depend on them. For now it's
harmless to remove all invocations of unit2minor() and minor2unit().

Reviewed by: kib

Custom DTrace kernel module files plus FreeBSD-specific DTrace providers.