Add detection for machine types 0x3931 and 0x3932 and set ELF platform
name to z16.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Machine generations up to z9 (released in May 2006) have been officially
out of service for several years now (z9 end of service - January 31, 2019).
No distributions build kernels supporting those old machine generations
anymore, except Debian, which seems to pick the oldest supported
generation. The team supporting Debian on s390 has been notified about
the change.

Raising minimum supported machine generation to z10 helps to reduce
maintenance cost and effectively remove code, which is not getting
enough testing coverage due to lack of older hardware and distributions
support. Besides that this unblocks some optimization opportunities and
allows to use wider instruction set in asm files for future features
implementation. Due to this change spectre mitigation and usercopy
implementations could be drastically simplified and many newer instructions
could be converted from ".insn" encoding to instruction names.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20210803141621.780504-5-bigeasy@linutronix.de
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Commit 7f16d7e787b7 ("s390: show virtualization support in /proc/cpuinfo")
introduced special handling for sie capability, saying this should not be
exposed via hwcaps, without giving a reason.

However this leads to an inconsistent /proc/cpuinfo features line
where all features except the sie capability are also present in
hwcaps. I really don't see a reason to not add that to hwcaps - it
might be quite pointless, but at least this way it is possible to get
rid of some special handling.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Remove the not so obvious "(elf_hwcap & (1UL << 2)" which only checks
if stfle is available. This used to be required for old code before
test_facility() was introduced. test_facility() will do the right
thing, regardless if stfle is available or not.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Remove a leftover from the common 31/64 bit code. z/Architecture mode
is now always active, there is no need to check.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Use a consistent coding style within setup_hwcaps() and remove obvious
and outdated comments.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

The first six hwcap bits are initialized in a rather odd way: an array
contains the stfl(e) bits which need to be set, so that the
corresponding bit position (= array index) within hwcaps are set.

Better open code it like it is done for all other bits, making it
obvious which bit is set when.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

setup_hwcaps() is a quite large function. Make it smaller by moving
the elf platform setup code into an independent setup function.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Move setup_hwcaps() to processor.c for two reasons:
- make setup.c a bit smaller
- have allmost all of the hwcap code in one file

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>