MFC r295856 (by des@):
Implement /proc/$$/limits.

MFC r297781 (by dchagin@):
More complete implementation of /proc/self/limits.
Fix the way the code accesses process limits struct - pointed out by mjg@.

MFC r298318, 298319 (by cem@):
Don't print uninitialized values and initialize error return before use.

PR: 207386

MFC r285394 (by mjg@):
vref the vnode passed to vn_fullpath.

MFH: 285685
Add support to the jail framework to be able to mount linsysfs(5) and linprocfs(5).

PR: 207179
Requested by: thomas@gibfest.dk
Reviewed by: jamie, bapt
Approved by: re (gjb)
Sponsored by: gandi.net
Differential Revision: https://reviews.freebsd.org/D5390

MFC r283478:

Simplify linprocfs_doprocenviron(). Remove extra proc visibility checks
and initialize pn_vis by well known procfs_candebug().

MFC r283475:

Convert Linux sigsets before showing.
Linux kernel displays sigset always as 16x4 bit mask.

MFC r283473:

Add support for /proc/<pid>/auxv.

MFC r283472:

Add vdso and stack names to the /proc/self/maps.

MFC r283421:

Introduce a new module linux_common.ko which is intended for the
following primary purposes:

1. Remove the dependency of linsysfs and linprocfs modules from linux.ko,
which will be architecture specific on amd64.

2. Incorporate into linux_common.ko general code for platforms on which
we'll support two Linuxulator modules (for both instruction set - 32 & 64 bit).

3. Move malloc(9) declaration to linux_common.ko, to enable getting memory
usage statistics properly.

Currently linux_common.ko incorporates a code from linux_mib.c and linux_util.c
and linprocfs, linsysfs and linux kernel modules depend on linux_common.ko.

Temporarily remove dtrace garbage from linux_mib.c and linux_util.c

MFC r283414:

Print out proper procmap entry for 64 bit binaries.

MFC r280981:

Remove unused code.

Sponsored by: The FreeBSD Foundation

MFC r283924

Provide vnode in memory map info for files on tmpfs

When providing memory map information to userland, populate the vnode pointer
for tmpfs files. Set the memory mapping to appear as a vnode type, to match
FreeBSD 9 behavior.

This fixes the use of tmpfs files with the dtrace pid provider,
procstat -v, procfs, linprocfs, pmc (pmcstat), and ptrace (PT_VM_ENTRY).

Submitted by: Eric Badger <eric@badgerio.us> (initial revision)
Obtained from: Dell Inc.
PR: 198431

MFC r262539:
linprocfs: add support for /sys/kernel/random/uuid

PR: kern/186187

MFC r283924

Provide vnode in memory map info for files on tmpfs

When providing memory map information to userland, populate the vnode pointer
for tmpfs files. Set the memory mapping to appear as a vnode type, to match
FreeBSD 9 behavior.

This fixes the use of tmpfs files with the dtrace pid provider,
procstat -v, procfs, linprocfs, pmc (pmcstat), and ptrace (PT_VM_ENTRY).

Submitted by: Eric Badger <eric@badgerio.us> (initial revision)
Obtained from: Dell Inc.
PR: 198431

MFC r262539:
linprocfs: add support for /sys/kernel/random/uuid

PR: kern/186187