MFC r330806-r330815, r330837, r330864, r330883

pc98 changes associated with the named commits are also included in this
commit, despite not having been made with the original commits due to its
removal in head.

r330806:
Minor cosmetic changes.

Make sure { on the same line as struct for all struct *devdesc. Move
some type definitions to next to the dv_type define, since that's what
sets the d_type.

r330807:
We can't use d_opendata for blkio storage.

open_disk uses d_opendata for it's own purpse. We can't store blkio
there. Fortunately, blkio is stored elsewhere and we never actually
retrieve blkio from d_opendata. Eliminate it as a source of confusion.
Eliminate all stores of d_opendata in efi since this layer doesn't own
that field.

r330808:
Make struct libi386_devdesc match the struct devdesc better

Move data to top and call it d_opendata.

r330809:
Use the actual struct devdesc at the start of all *_devdesc structs

The current system is fragile and requires very careful layout of all
*_devdesc structures. It also makes it hard to change the base
devdesc. Take a page from CAM and put the 'header' in all the derived
classes and adjust the code to match.

For OFW, move the iHandle h_handle out of a slot conflicting with
d_opendata. Due to quirks in the alignment rules, this worked.
However changing the code to use d_opendata storage now that it's a
pointer is hard, so just have a separate field for it.

All other cleanups were to make the *_devdesc structures match where
they'd taken some liberties that were none-the-less compatible enough
to work.

r330810:
Remove d_type from devdesc. It's not needed as we can fetch it from
d_dev->dv_type when we need it.

r330811:
GC unused routines.

Sponsored by: Netflix

r330812:
Use the one-line-per-file pattern here, and sort the file names.

Sponsored by: Netflix

r330813:
Move the env convenience routines out of boot1.c.

These routines are more generally useful. Even though boot1 is on its
way out, it's better to make these common during the transition than
copy them.

r330814:
Star BootCurrent entry when booting.

Sponsored by: Netflix

r330815:
Print the load and device path as well as BootCurrent and BootOrder

Sponsored by: Netflix

r330837:
biosdisk.c should not set d_opendata.

Same as 330807, d_opendata is owned by open_disk and we should not
set it.

M stand/i386/libi386/biosdisk.c

r330864:
Prefer uintXX_t to u_intXX_t

A foolish consistency is the hobgoblin of little minds, adored by
little statesmen and philosophers and divines. With consistency a
great soul has simply nothing to do. -- Ralph Waldo Emerson

r330883:
Fix typo that misteriously passes compilation.

MFC r325834,r325997,326502: Move sys/boot to stand/

This is effectively a direct commit to stable/11, due to differences between
stable/11 and head. Changes to DTS in sys/boot/fdt/dts were often
accompanied by kernel changes. Many of these were also risc-v updates that
likely had many more dependencies to MFC.

Because of this, sys/boot/fdt/dts remains as-is while everything else in
sys/boot relocates to stand/.

r325834: Move sys/boot to stand. Fix all references to new location

r325997: Remove empty directories.

r326502: Document the sys/boot -> stand move in hier.7 and the top-level README.

MFC r324551: Move lib/libstand to sys/boot/libsa

MFC r309369,310850,310853:

libstand: dosfs cstyle cleanup for return keyword.
dosfs support in libstand is broken since r298230

PR: 214423
Submitted by: Mikhail Kupchik
Reported by: Mikhail Kupchik
Approved by: imp (mentor)

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

A new implementation of the loader block cache

The block cache implementation in loader has proven to be almost useless, and in worst case even slowing down the disk reads due to insufficient cache size and extra memory copy.
Also the current cache implementation does not cache reads from CDs, or work with zfs built on top of multiple disks.
Instead of an LRU, this code uses a simple hash (O(1) read from cache), and instead of a single global cache, a separate cache per block device.
The cache also implements limited read-ahead to increase performance.
To simplify read ahead management, the read ahead will not wrap over bcache end, so in worst case, single block physical read will be performed to fill the last block in bcache.

Booting from a virtual CD over IPMI:
0ms latency, before: 27 second, after: 7 seconds
60ms latency, before: over 12 minutes, after: under 5 minutes.

Submitted by: Toomas Soome <tsoome@me.com>
Reviewed by: delphij (previous version), emaste (previous version)
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D4713

Add a divisor parameter to twiddle() so that callers can request that output
only happen on every Nth call. Update the existing twiddle() calls done in
various IO loops to roughly reflect the relative IO sizes. That is, tftp
and nfs call twiddle() on every 1K block, ufs on every filesystem block,
so the network calls now use a much larger divisor than disk IO calls.

Also add a new twiddle_divisor() function that allows an application to set
a global divisor that is applied on top of the per-call divisors. Nothing
calls this yet, but loader(8) will be using it to further throttle the
cursor for slow serial consoles.

libstand: Reset the seek pointer in ext2fs as done in UFS.

Based on r134760:

Reset the seek pointer to 0 when a file is successfully opened,
since otherwise the initial seek offset will contain the directory
offset of the filesystem block that contained its directory entry.
This bug was mostly harmless because typically the directory is
less than one filesystem block in size so the offset would be zero.
It did however generally break loading a kernel from the (large)
kernel compile directory.

Also reset the seek pointer when a new inode is opened in read_inode(),
though this is not actually necessary now because all callers set
it afterwards.

PR: 177328
Submitted by: Eric van Gyzen
Reviewed by: iedowse
MFC after: 5 days

Don't add integers to void pointers.

Clean up error handling in libstand filesystem code to be more consistent:
- bzipfs and gzipfs now properly return errno values directly from their
read routines rather than returning -1.
- missing errno values on error returns for the seek routines on almost
all filesystems were added.
- fstat() now returns -1 if an error occurs rather than ignoring it.
- nfs's readdir() routine now reports valid errno values if an error or
EOF occurs rather than EPERM (It was just returning 0 for success and
1 for failure).
- nullfs used the wrong semantics for every function besides close() and
seek(). Getting it right for close() appears to be an accident at that.
- read() for buffered files no longer returns 0 (EOF) if an error occurs,
but returns -1 instead.

Use an explicitly-sized type instead of daddr_t for on-disk block
numbers.

Add __FBSDID()s to libstand

Fix typo: compatability -> compatibility.

Compatability is not an existing english word.

Add ext2fs support to the loader.