Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

MFC r311101:
libkvm - extend a bit the swap statistics field.

Change ksw_used and ksw_total to unsigned, which increases the maximum
total swap that can be displayed properly from ~8TB to ~16TB.

Obtained from: DragonflyBSD (ecc2e461)

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Add support to libkvm for reading vmcores from other architectures.
- Add a kvaddr_type to represent kernel virtual addresses instead of
unsigned long.
- Add a struct kvm_nlist which is a stripped down version of struct nlist
that uses kvaddr_t for n_value.
- Add a kvm_native() routine that returns true if an open kvm descriptor
is for a native kernel and memory image.
- Add a kvm_open2() function similar to kvm_openfiles(). It drops the
unused 'swapfile' argument and adds a new function pointer argument for
a symbol resolving function. Native kernels still use _fdnlist() from
libc to resolve symbols if a resolver function is not supplied, but cross
kernels require a resolver.
- Add a kvm_nlist2() function similar to kvm_nlist() except that it uses
struct kvm_nlist instead of struct nlist.
- Add a kvm_read2() function similar to kvm_read() except that it uses
kvaddr_t instead of unsigned long for the kernel virtual address.
- Add a new kvm_arch switch of routines needed by a vmcore backend.
Each backend is responsible for implementing kvm_read2() for a given
vmcore format.
- Use libelf to read headers from ELF kernels and cores (except for
powerpc cores).
- Add internal helper routines for the common page offset hash table used
by the minidump backends.
- Port all of the existing kvm backends to implement a kvm_arch switch and
to be cross-friendly by using private constants instead of ones that
vary by platform (e.g. PAGE_SIZE). Static assertions are present when
a given backend is compiled natively to ensure the private constants
match the real ones.
- Enable all of the existing vmcore backends on all platforms. This means
that libkvm on any platform should be able to perform KVA translation
and read data from a vmcore of any platform.

Tested on: amd64, i386, sparc64 (marius)
Differential Revision: https://reviews.freebsd.org/D3341

Remove trailing whitespace.

libkvm code janitoring

- make WARNS=6 clean for archs w/o strict alignment requirments
- add const, ANSIfy, remove unused vars, cast types for comparison
- thanks to differing definitions of VM_MIN_ADDRESS across our archs, we
need to trick the compiler to not complain about signedness. We could
either fix VM_MIN_ADDRESS to always be a simple integer or make the
check conditional on $ARCH.

Closes PRs: kern/42386, kern/83364
Reviewed by: bde

- Move 'struct swdevt' back into swap_pager.h and expose it to userland.
- Restore support for fetching swap information from crash dumps via
kvm_get_swapinfo(3) to fix pstat -T/-s on crash dumps.

Reviewed by: arch@, phk
MFC after: 1 week

Expand the license referenced indirectly inline.

Remove various unused variables, prototypes and local variables.

Disable and lobotomize the kvm image reading swapinfo code, the kernel
layout is about to change.

The sysctl based method still returns correct information.

Retire the SWIF_DUMP_TREE code, this is in the way for a rework of
the swap_pager layout.

Unifdef -UDEBUG_SWAPINFO The kernel data structures are about to change.

Remove all use of the LOG2() macro/inline, undoing some non-optimal cruft
that crept in recently. GCC will optimize the divides and multiplies for us.

Submitted by: David Schultz <dschultz@uclink.Berkeley.EDU>
MFC after: 1 day

Make struct swblock kernel only, to make vm/swap_pager.h userland includable.
Move struct swdevt from sys/conf.h to the more appropriate vm/swap_pager.h.
Adjust #include use in libkvm and pstat(8) to match.

Compensate for "Compensate for header dethreading" by backing it out.

Implement __FBSDID()

Change this to support the new way swap device information is exported
via sysctl, and clean up some style and (size_t != int) issues.

Compensate for header dethreading.

Adapt libkvm_getswapinfo() to make use of recently committed vm and swap
sysctls exporting swap information. When running on a live kernel,
the sysctl's will now be used instead of kvm_read, allowing consumers of
this interface to run without privilege (setgid kmem). Retain the
ability to run on coredumps, or on a kernel using kmem if explicitly
pointed at one.

A side effect of this change is that kvm_getswapinfo() is faster now in
the general case. If the SWIF_DUMP_TREE flag is given (pstat -ss does
this), the radix tree walker, which still uses kvm_read in any case, is
invoked, and therefore does require privilege.

Submitted by: Thomas Moestl <tmoestl@gmx.net>
Reviewed by: freebsd-audit

Add `_PATH_DEVZERO'.
Use _PATH_* where where possible.

remove unneded sys/ucred.h include

Remove unneeded #include

-Wall, which caught a real bug where buflen wasn't being set properly.

Use kldsym(2) to lookup symbol values. This avoids the kvm_mkdb juggling
and is module aware. Yes, this means that kvm_nlist(3) will find symbols
in loaded modules. The emulation of the nlist struct is pretty crude but
seems to work well enough for all the users in the tree that I found.

Report swapdevices as cdevs rather than bdevs.

Remove unused dev2budev() function.

$Id$ -> $FreeBSD$

Tidy up references to <sys/rlist.h> and support for the old swap management
that went away in January.

From rev. 1.12 of usr.sbin/pstat/pstat.c by phk:
Reflect the fact that we do not swap on the first <dmmax> blocks of a
swapdev, to protect disklabels and other such magic stuff.

Handle case where no swap is configured

Removed evil typedef kvm_swap_t and all uses of it (not many).

Hoped for by: wollman

Fix swap radix tree dump formatting ( pstat -ss ), it was printing the
wrong radix for recursive subnodes.

Add SWIF_DEV_PREFIX flag to add "/dev/..." to device name.

Implement kvm_getswapinfo() libkvm function. Will be used by
pstat, top, and systat.