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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

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

Remove checks for <sys/cdefs.h> being included.

These files no longer depend on the macros required when these checks
were added.

PR: 263102 (exp-run)
Reviewed by: brooks, imp, emaste
Differential Revision: https://reviews.freebsd.org/D34804

Remove checks for __GNUCLIKE___SECTION assuming it is always true.

All supported compilers (modern versions of GCC and clang) support
this.

PR: 263102 (exp-run)
Reviewed by: brooks, imp, emaste
Differential Revision: https://reviews.freebsd.org/D34799

linker_set: Disable ASAN only in userspace

KASAN does not insert redzones around global variables and so is not
susceptible to the problem that led to us disabling ASAN for linker set
elements in the first place (see commit fe3d8086fb6f).

Reviewed by: andrew, kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D30126

linker_set: fix globl/weak symbol redefinitions to work on clang 12

In clang 12.0.0.rc2, going from weak to global is now a hard error:

```
/usr/src/stand/libsa/amd64/_setjmp.S:67:25: error: _longjmp changed binding to STB_GLOBAL
.text; .p2align 4,0x90; .globl _longjmp; .type _longjmp,@function; _longjmp:; .cfi_startproc
```

And the other way is a warning, but we have -Werror:

```
error: __start_set_Xcommand_set changed binding to STB_WEAK [-Werror,-Winline-asm]
error: __stop_set_Xcommand_set changed binding to STB_WEAK [-Werror,-Winline-asm]
```

ref: https://reviews.llvm.org/D90108

Reviewed By: arichardson
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D29159

[PowerPC] Only move linker sets to .data on ELFv1

In r268055, powerpc64 was special cased regarding linker sets to not mark
the function pointer as 'const'.

This appears to have been done to ensure the compiler generates the function
descriptors correctly. When non-const, the function descriptors will end up
in the .data.rel.local section, and the linker set symbols will get
relocations pointing to them there.

Since function pointers on ELFv2 are "just" pointers like other platforms,
we can leave them const like they are on every other platform.

Reviewed by: jhibbits
Differential Revision: https://reviews.freebsd.org/D22796

Don't sanitize linker_set

The assumptions of linker_set don't play nicely with
AddressSanitizer. AddressSanitizer adds a 'redzone' of zeros around
globals (including those in named sections), whereas linker_set
assumes they are all packed consecutively like a pointer array. So:
let's annotate linker_set so that AddressSanitizer ignores it.

Submitted by: Matthew Bryan <matthew.bryan@isilon.com>
Reviewed by: kib, rang_acm.org
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D22239

Move sysinit and sysuninit linker sets in the data (writeable) section.

Both sets are sorted in place, and with the introduction of read-only
permissions on the amd64 kernel text, the sorting override depended on
CR0.WP turned off. Make it correct by moving the sets into writeable
part of the KVA, also fixing boot on machines where hand-off from BIOS
to OS occurs with CR0.WP set.

Based on submission by: Peter Lei <peter.lei@ieee.org>
MFC after: 1 week

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.

Remove lint support from system headers and MD x86 headers.

Reviewed by: dim, jhb
Discussed with: imp
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D13156

Rename __weak to __weak_symbol to avoid language conflict with objective-C.

PR: 200972 (exp-run)
Suggested by: theraven@
MFC after: 3 days

Add support for empty data sets. Data set begin and end pointers
should resolve to "NULL" when not present. This is done by declaring
the data set begin and end symbols as "weak".

Workaround for bug in GCC on powerpc64. Symbols that are exported are
by fault required to be all "static" or all "extern".

After some off-list discussion, revert a number of changes to the
DPCPU_DEFINE and VNET_DEFINE macros, as these cause problems for various
people working on the affected files. A better long-term solution is
still being considered. This reversal may give some modules empty
set_pcpu or set_vnet sections, but these are harmless.

Changes reverted:

------------------------------------------------------------------------
r215318 | dim | 2010-11-14 21:40:55 +0100 (Sun, 14 Nov 2010) | 4 lines

Instead of unconditionally emitting .globl's for the __start_set_xxx and
__stop_set_xxx symbols, only emit them when the set_vnet or set_pcpu
sections are actually defined.

------------------------------------------------------------------------
r215317 | dim | 2010-11-14 21:38:11 +0100 (Sun, 14 Nov 2010) | 3 lines

Apply the STATIC_VNET_DEFINE and STATIC_DPCPU_DEFINE macros throughout
the tree.

------------------------------------------------------------------------
r215316 | dim | 2010-11-14 21:23:02 +0100 (Sun, 14 Nov 2010) | 2 lines

Add macros to define static instances of VNET_DEFINE and DPCPU_DEFINE.

Instead of unconditionally emitting .globl's for the __start_set_xxx and
__stop_set_xxx symbols, only emit them when the set_vnet or set_pcpu
sections are actually defined.

Revert r103230, which depended on ld preserving the __start_xxx and
__stop_xxx symbols for custom sections, even when these were not
referenced (at link time). This behaviour was changed again in binutils
commit 0b8ed435c3fe8bd09a08c23920e65bfb03251221.

This time, put the __GLOBL macro definition in cdefs.h, so it can be
reused in a few other places where it will be needed.

Reviewed by: kib

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

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

netchild's mega-patch to isolate compiler dependencies into a central
place.

This moves the dependency on GCC's and other compiler's features into
the central sys/cdefs.h file, while the individual source files can
then refer to #ifdef __COMPILER_FEATURE_FOO where they by now used to
refer to #if __GNUC__ > 3.1415 && __BARC__ <= 42.

By now, GCC and ICC (the Intel compiler) have been actively tested on
IA32 platforms by netchild. Extension to other compilers is supposed
to be possible, of course.

Submitted by: netchild
Reviewed by: various developers on arch@, some time ago

Typo fix.

Emply __used attribute to prevent compiler from removing unreferenced
static symbols. This wasn't a problem with previous GCC releases, but
unit-at-a-time mode of GCC 3.4.2 prevents linker set components from
being emitted at all.

These are changes to allow to use the Intel C/C++ compiler (lang/icc)
to build the kernel. It doesn't affect the operation if gcc.

Most of the changes are just adding __INTEL_COMPILER to #ifdef's, as
icc v8 may define __GNUC__ some parts may look strange but are
necessary.

Additional changes:
- in_cksum.[ch]:
* use a generic C version instead of the assembly version in the !gcc
case (ASM code breaks with the optimizations icc does)
-> no bad checksums with an icc compiled kernel
Help from: andre, grehan, das
Stolen from: alpha version via ppc version
The entire checksum code should IMHO be replaced with the DragonFly
version (because it isn't guaranteed future revisions of gcc will
include similar optimizations) as in:
---snip---
Revision Changes Path
1.12 +1 -0 src/sys/conf/files.i386
1.4 +142 -558 src/sys/i386/i386/in_cksum.c
1.5 +33 -69 src/sys/i386/include/in_cksum.h
1.5 +2 -0 src/sys/netinet/igmp.c
1.6 +0 -1 src/sys/netinet/in.h
1.6 +2 -0 src/sys/netinet/ip_icmp.c

1.4 +3 -4 src/contrib/ipfilter/ip_compat.h
1.3 +1 -2 src/sbin/natd/icmp.c
1.4 +0 -1 src/sbin/natd/natd.c
1.48 +1 -0 src/sys/conf/files
1.2 +0 -1 src/sys/conf/files.amd64
1.13 +0 -1 src/sys/conf/files.i386
1.5 +0 -1 src/sys/conf/files.pc98
1.7 +1 -1 src/sys/contrib/ipfilter/netinet/fil.c
1.10 +2 -3 src/sys/contrib/ipfilter/netinet/ip_compat.h
1.10 +1 -1 src/sys/contrib/ipfilter/netinet/ip_fil.c
1.7 +1 -1 src/sys/dev/netif/txp/if_txp.c
1.7 +1 -1 src/sys/net/ip_mroute/ip_mroute.c
1.7 +1 -2 src/sys/net/ipfw/ip_fw2.c
1.6 +1 -2 src/sys/netinet/igmp.c
1.4 +158 -116 src/sys/netinet/in_cksum.c
1.6 +1 -1 src/sys/netinet/ip_gre.c
1.7 +1 -2 src/sys/netinet/ip_icmp.c
1.10 +1 -1 src/sys/netinet/ip_input.c
1.10 +1 -2 src/sys/netinet/ip_output.c
1.13 +1 -2 src/sys/netinet/tcp_input.c
1.9 +1 -2 src/sys/netinet/tcp_output.c
1.10 +1 -1 src/sys/netinet/tcp_subr.c
1.10 +1 -1 src/sys/netinet/tcp_syncache.c
1.9 +1 -2 src/sys/netinet/udp_usrreq.c

1.5 +1 -2 src/sys/netinet6/ipsec.c
1.5 +1 -2 src/sys/netproto/ipsec/ipsec.c
1.5 +1 -1 src/sys/netproto/ipsec/ipsec_input.c
1.4 +1 -2 src/sys/netproto/ipsec/ipsec_output.c

and finally remove
sys/i386/i386 in_cksum.c
sys/i386/include in_cksum.h
---snip---
- endian.h:
* DTRT in C++ mode
- quad.h:
* we don't use gcc v1 anymore, remove support for it
Suggested by: bde (long ago)
- assym.h:
* avoid zero-length arrays (remove dependency on a gcc specific
feature)
This change changes the contents of the object file, but as it's
only used to generate some values for a header, and the generator
knows how to handle this, there's no impact in the gcc case.
Explained by: bde
Submitted by: Marius Strobl <marius@alchemy.franken.de>
- aicasm.c:
* minor change to teach it about the way icc spells "-nostdinc"
Not approved by: gibbs (no reply to my mail)
- bump __FreeBSD_version (lang/icc needs to know about the changes)

Incarnations of this patch survive gcc compiles since a loooong time,
I use it on my desktop. An icc compiled kernel works since Nov. 2003
(exceptions: snd_* if used as modules), it survives a build of the
entire ports collection with icc.

Parts of this commit contains suggestions or submissions from
Marius Strobl <marius@alchemy.franken.de>.

Reviewed by: -arch
Submitted by: netchild

Add a __section(x) macro as well. Use this in linker_set.h. ie:
static void const * const __set_##set##_sym_##sym
__attribute__((__section__("set_" #set),__unused__)) = &sym
becomes:
static void const * const __set_##set##_sym_##sym
__section("set_" #set) __unused = &sym
Like the other macros, these #define away for unrecognized compilers or
lint.

Also, fix the argments in the previous commit for the non-gcc case. lint
might be a bit happier about that. Note that the gcc <= 2.6 case
needs some research.

Initiate deorbit burn for the i386-only a.out related support. Moves are
under way to move the remnants of the a.out toolchain to ports. As the
comment in src/Makefile said, this stuff is deprecated and one should not
expect this to remain beyond 4.0-REL. It has already lasted WAY beyond
that.

Notable exceptions:
gcc - I have not touched the a.out generation stuff there.
ldd/ldconfig - still have some code to interface with a.out rtld.
old as/ld/etc - I have not removed these yet, pending their move to ports.
some includes - necessary for ldd/ldconfig for now.

Tested on: i386 (extensively), alpha

Sometime after binutils-2.9 (ie: ages ago), the handling of __start_set_*
and __stop_set_* became friendlier. This trick to force the export
of the section delimiter symbols is no longer necessary. We needed to
force this so that we could look up the symbols via a symbol table search
when the module was loaded at run time. ld used to eliminate them if
they were not referenced at compile/link time.

Wrap GCC-specific stuff and provide alternative for lint.

With this commit, I hereby pronounce gensetdefs past its use-by date.

Replace the a.out emulation of 'struct linker_set' with something
a little more flexible. <sys/linker_set.h> now provides macros for
accessing elements and completely hides the implementation.

The linker_set.h macros have been on the back burner in various
forms since 1998 and has ideas and code from Mike Smith (SET_FOREACH()),
John Polstra (ELF clue) and myself (cleaned up API and the conversion
of the rest of the kernel to use it).

The macros declare a strongly typed set. They return elements with the
type that you declare the set with, rather than a generic void *.

For ELF, we use the magic ld symbols (__start_<setname> and
__stop_<setname>). Thanks to Richard Henderson <rth@redhat.com> for the
trick about how to force ld to provide them for kld's.

For a.out, we use the old linker_set struct.

NOTE: the item lists are no longer null terminated. This is why
the code impact is high in certain areas.

The runtime linker has a new method to find the linker set
boundaries depending on which backend format is in use.

linker sets are still module/kld unfriendly and should never be used
for anything that may be modular one day.

Reviewed by: eivind

Remove underscores from linker set stabs for the a.out case, after
the demise of asnames.h.

o Add explicit alignment to linker set definitions. On i386, data
declarations will not be aligned by default.
o Remove the alignment work-around for alpha. Our current alpha
as(1) does not assume alignment after section switching, nor
does the ia64 as(1).

Change ".align 3" to ".p2align 3" so that this works with ia64.

Add a comment explaining the obscure lines:

static void const * const __set_##set##_sym_##sym = &sym;

in the MAKE_SET macros.

$Id$ -> $FreeBSD$

ABS_SET() and BSS_SET() are no longer used. The sole remaining user of
TEXT_SET() is DDB's command tables.

ls_items[] is most definately not a set of pointers to const objects..
sysinits, for example, are sorted by swapping those objects(!). Perhaps
they should be const and the sysinit sorting should be swapping the
pointers rather than the targets. This is on my revisit list, but it
has the side effect of removing a lot of warnings. With -Wcast-qual, it
doesn't seem easy to get rid of the constness when you *know* it's not.
(With apologies to bde, this essentially reverts rev 1.21 of kernel.h
from back in 1996)

Move the linker set definitions into a new header file
<sys/linker_set.h>. <sys/kernel.h> includes the new header, so
functionally everything is still the same.