sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

malloc: delegate M_EXEC handling to dedicacted routines

It is almost never needed and adds an avoidable branch.

While here do minior clean ups in preparation for larger changes.

Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D27019

Make UMA and malloc(9) return non-executable memory in most cases.

Most kernel memory that is allocated after boot does not need to be
executable. There are a few exceptions. For example, kernel modules
do need executable memory, but they don't use UMA or malloc(9). The
BPF JIT compiler also needs executable memory and did use malloc(9)
until r317072.

(Note that a side effect of r316767 was that the "small allocation"
path in UMA on amd64 already returned non-executable memory. This
meant that some calls to malloc(9) or the UMA zone(9) allocator could
return executable memory, while others could return non-executable
memory. This change makes the behavior consistent.)

This change makes malloc(9) return non-executable memory unless the new
M_EXEC flag is specified. After this change, the UMA zone(9) allocator
will always return non-executable memory, and a KASSERT will catch
attempts to use the M_EXEC flag to allocate executable memory using
uma_zalloc() or its variants.

Allocations that do need executable memory have various choices. They
may use the M_EXEC flag to malloc(9), or they may use a different VM
interfact to obtain executable pages.

Now that malloc(9) again allows executable allocations, this change also
reverts most of r317072.

PR: 228927
Reviewed by: alc, kib, markj, jhb (previous version)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D15691

Revert r327828, r327949, r327953, r328016-r328026, r328041:
Uses of mallocarray(9).

The use of mallocarray(9) has rocketed the required swap to build FreeBSD.
This is likely caused by the allocation size attributes which put extra pressure
on the compiler.

Given that most of these checks are superfluous we have to choose better
where to use mallocarray(9). We still have more uses of mallocarray(9) but
hopefully this is enough to bring swap usage to a reasonable level.

Reported by: wosch
PR: 225197

x86: make some use of mallocarray(9).

Focus on code where we are doing multiplications within malloc(9). None of
these ire likely to overflow, however the change is still useful as some
static checkers can benefit from the allocation attributes we use for
mallocarray.

This initial sweep only covers malloc(9) calls with M_NOWAIT. No good
reason but I started doing the changes before r327796 and at that time it
was convenient to make sure the sorrounding code could handle NULL values.

X-Differential revision: https://reviews.freebsd.org/D13837

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

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.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Use kmem_malloc() instead of malloc(9) for the native amd64 filter.

r316767 broke the BPF JIT compiler for amd64 because malloc()'d space is no
longer executable.

Discussed with: kib, alc

Move declarations for a machine-dependent function to the header file.

Implement BPF_MOD and BPF_XOR instructions.

These two ALU instructions first appeared on Linux. Then, libpcap adopted
and made them available since 1.6.2. Now more platforms including NetBSD
have them in kernel. So do we.
--이 줄 이하는 자동으로 제거됩니다--

Redude code for conditional jumps.

Fix compiler warnings for user land.

Provide includes that are needed in these files, and before were read
in implicitly via if.h -> if_var.h pollution.

Sponsored by: Netflix
Sponsored by: Nginx, Inc.

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

If a conditional jump instruction has the same jt and jf, do not perform
the test and jump unconditionally.

- Add more aggressive BPF JIT optimization. This is in more favor of i386
while the previous commit was more amd64-centric.
- Use calloc(3) instead of malloc(3)/memset(3) in user land[1].

Submitted by: ed[1]

Add an experimental and rudimentary JIT optimizer to reduce unncessary
overhead from short BPF filter programs such as "get the first 96 bytes".

General style cleanup, no functional change.

- Allocate scratch memory on stack instead of pre-allocating it with
the filter as we do from bpf_filter()[1].
- Revert experimental use of contigmalloc(9)/contigfree(9). It has no
performance benefit over malloc(9)/free(9)[2].

Requested by: rwatson[1]
Pointed out by: rwatson, jhb, alc[2]

Fix tinderbox build for i386 and sync amd64 with it.

- Change internal function bpf_jit_compile() to return allocated size of
the generated binary and remove page size limitation for userland.
- Use contigmalloc(9)/contigfree(9) instead of malloc(9)/free(9) to make
sure the generated binary aligns properly and make it physically contiguous.

- Make BPF JIT compiler working again in userland. We are limiting size of
generated native binary to page size for now.
- Update copyright date and fix some style nits.

- Import the HEAD csup code which is the basis for the cvsmode work.

Move empty filter handling to MI source.

MFC after: 3 days

Fix a typo in copyrights.

Correctly check unsignedness of all BPF_LD|BPF_IND instructions.
This is roughly from sys/net/bpf_filter.c r1.12 and r1.14.

- Make these files compilable on user land.
- Update copyrights and fix style(9).

Use int32_t/int16_t instead of int/short as sys/net/bpf_filter.c does.

- Remove unnecessary jump instruction(s) when offset(s) is/are zero(s).
- Constantly use conditional jumps for unsigned integers.

Update copyrights and fix style(9).

Replace all stack usages with registers and remove unused macros.

Emit opcodes closer to GNU as(1) generated codes and micro-optimize.

Rehash and clean up BPF JIT compiler macros to match AT&T notations.

- Explicitly validate an empty filter to match bpf_filter() comment[1].
- Do not use BPF JIT compiler for an empty filter.

[1] Pointed out by: darrenr

s/M_WAITOK/M_NOWAIT/ while mutex is held.

Pointed out by: csjp

- Micro-optimize `mov $0, %edx' -> `xor %edx, %edx'.
- Correct amd64 macro style (no functional change).

Add experimental BPF Just-In-Time compiler for amd64 and i386.

Use the following kernel configuration option to enable:

options BPF_JITTER

If you want to use bpf_filter() instead (e. g., debugging), do:

sysctl net.bpf.jitter.enable=0

to turn it off.

Currently BIOCSETWF and bpf_mtap2() are unsupported, and bpf_mtap() is
partially supported because 1) no need, 2) avoid expensive m_copydata(9).

Obtained from: WinPcap 3.1 (for i386)