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

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

dtrace: Add a "regs" variable

This allows invop-based providers (i.e., fbt and kinst) to expose the
register file of the CPU at the point where the probe fired. It does
not work for SDT providers b

dtrace: Add a "regs" variable

This allows invop-based providers (i.e., fbt and kinst) to expose the
register file of the CPU at the point where the probe fired. It does
not work for SDT providers because their probes are implemented as plain
function calls and so don't save registers. It's not clear what
semantics "regs" should have for them anyway.

This is akin to "uregs", which nominally provides access to the
userspace registers. In fact, DIF already had a DIF_VAR_REGS variable
defined, it was simply unimplemented.

Usage example: print the contents of %rdi upon each call to
amd64_syscall():

fbt::amd64_syscall:entry {printf("%x", regs[R_RDI]);}

Note that the R_* constants are defined in /usr/lib/dtrace/regs_x86.d.
Currently there are no similar definitions for non-x86 platforms.

Reviewed by: christos
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D36799

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Adjust function definition in arm's dtrace_subr.c to avoid clang 15 warning

With clang 15, the following -Werror warning is produced:

sys/cddl/dev/dtrace/arm/dtrace_subr.c:174:17: error: a func

Adjust function definition in arm's dtrace_subr.c to avoid clang 15 warning

With clang 15, the following -Werror warning is produced:

sys/cddl/dev/dtrace/arm/dtrace_subr.c:174:17: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
dtrace_gethrtime()
^
void

This is because dtrace_gethrtime() is declared with a (void) argument
list, but defined with an empty argument list. Make the definition match
the declaration.

MFC after: 3 days

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Changes that improve DTrace FBT reliability on freebsd/arm64:

- Implement a dtrace_getnanouptime(), matching the existing
dtrace_getnanotime(), to avoid DTrace calling out to a potentially
instr

Changes that improve DTrace FBT reliability on freebsd/arm64:

- Implement a dtrace_getnanouptime(), matching the existing
dtrace_getnanotime(), to avoid DTrace calling out to a potentially
instrumentable function.

(These should probably both be under KDTRACE_HOOKS. Also, it's not clear
to me that they are correct implementations for the DTrace thread time
functions they are used in .. fixes for another commit.)

- Don't allow FBT to instrument functions involved in EL1 exception handling
that are involved in FBT trap processing: handle_el1h_sync() and
do_el1h_sync().

- Don't allow FBT to instrument DDB and KDB functions, as that makes it
rather harder to debug FBT problems.

Prior to these changes, use of FBT on FreeBSD/arm64 rapidly led to kernel
panics due to recursion in DTrace.

Reliable FBT on FreeBSD/arm64 is reliant on another change from @andrew to
have the aarch64 instrumentor more carefully check that instructions it
replaces are against the stack pointer, which can otherwise lead to memory
corruption. That change remains under review.

MFC after: 2 weeks
Reviewed by: andrew, kp, markj (earlier version), jrtc27 (earlier version)
Differential revision: https://reviews.freebsd.org/D27766

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MFH

Sponsored by: Rubicon Communications, LLC (netgate.com)

dtrace/fbt: fix return probe arguments on arm

arg0 should be an offset of the return point within the function, arg1
should be the return value. Previously the return probe had arguments as
if for

dtrace/fbt: fix return probe arguments on arm

arg0 should be an offset of the return point within the function, arg1
should be the return value. Previously the return probe had arguments as
if for the entry probe.

Tested on armv7.

andrew noted that the same problem seems to be present on arm64, mips,
and riscv.
I am not sure if I will get around to fixing those. So, platform users
or anyone looking to make a contribution please be aware of this
opportunity.

Reviewed by: markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D25685

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Remove scary-looking printf output that happens when you kldload dtrace on
arm. Replace it with a comment block explaining why the function is empty
on 32-bit arm.

Corrected misspelled versions of rendezvous.

The MFC will include a compat definition of smp_no_rendevous_barrier()
that calls smp_no_rendezvous_barrier().

Reviewed by: gnn, kib
MFC after: 1 week
D

Corrected misspelled versions of rendezvous.

The MFC will include a compat definition of smp_no_rendevous_barrier()
that calls smp_no_rendezvous_barrier().

Reviewed by: gnn, kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D10313

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Merge ^/head r308227 through r308490.

Fix improper use of "its".

Sponsored by: Dell EMC Isilon

Make the second argument of dtrace_invop() a trapframe pointer.

Currently this argument is a pointer into the stack which is used by FBT
to fetch the first five probe arguments. On all non-x86 archi

Make the second argument of dtrace_invop() a trapframe pointer.

Currently this argument is a pointer into the stack which is used by FBT
to fetch the first five probe arguments. On all non-x86 architectures it's
simply the trapframe address, so this change has no functional impact. On
amd64 it's a pointer into the trapframe such that stack[1 .. 5] gives the
first five argument registers, which are deliberately grouped together in
the amd64 trapframe definition.

A trapframe argument simplifies the invop handlers on !x86 and makes the
x86 FBT invop handler easier to understand. Moreover, it allows for invop
handlers that may want to modify the register set of the interrupted thread.

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MFH

Sponsored by: The FreeBSD Foundation

Remove unused variables dtrace_in_probe and dtrace_in_probe_addr.

Merge sync of head

MFH: r278968-r280640

Sponsored by: The FreeBSD Foundation

Merge r278538 through r280226.

Merge from head

Merging ^/head r279596 through r279758.

Add support for walltimestamp to DTrace on ARM.

Merge r278538 through r279716.

Add the MD parts of dtrace needed to use fbt on ARM. For this we need to
emulate the instructions used in function entry and exit.

For function entry ARM will use a push instruction to push up to 16

Add the MD parts of dtrace needed to use fbt on ARM. For this we need to
emulate the instructions used in function entry and exit.

For function entry ARM will use a push instruction to push up to 16
registers to the stack. While we don't expect all 16 to be used we need to
handle any combination the compiler may generate, even if it doesn't make
sense (e.g. pushing the program counter).

On function return we will either have a pop or branch instruction. The
former is similar to the push instruction, but with care to make sure we
update the stack pointer and program counter correctly in the cases they
are either in the list of registers or not. For branch we need to take the
24-bit offset, sign-extend it, and add that number of 4-byte words to the
program counter. Care needs to be taken as, due to historical reasons, the
address the branch is relative to is not the current instruction, but 8
bytes later.

This allows us to use the following probes on ARM boards:
dtrace -n 'fbt::malloc:entry { stack() }'
and
dtrace -n 'fbt::free:return { stack() }'

Differential Revision: https://reviews.freebsd.org/D2007
Reviewed by: gnn, rpaulo
Sponsored by: ABT Systems Ltd

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Merge ^/head r278499 through r278755.

Merge from HEAD

MFH: r278202,r278205-r278590

Sponsored by: The FreeBSD Foundation

Initial version of DTrace on ARM32.

Submitted by: Howard Su based on work by Oleksandr Tymoshenko
Reviewed by: ian, andrew, rpaulo, markj