linux.git/arch/s390/kernel/processor.c, branch v6.9

s390/fpu: get rid of MACHINE_HAS_VX

2023-12-11T13:33:07+00:00

Get rid of MACHINE_HAS_VX and replace it with cpu_has_vx() which is a
short readable wrapper for "test_facility(129)".

Facility bit 129 is set if the vector facility is present. test_facility()
returns also true for all bits which are set in the architecture level set
of the cpu that the kernel is compiled for. This means that
test_facility(129) is a compile time constant which returns true for z13
and later, since the vector facility bit is part of the z13 kernel ALS.

In result the compiled code will have less runtime checks, and less code.

Reviewed-by: Hendrik Brueckner 
Signed-off-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev

s390/fpu: remove "novx" option

2023-12-11T13:33:06+00:00

Remove the "novx" kernel command line option: the vector code runs
without any problems since many years.

Reviewed-by: Hendrik Brueckner 
Signed-off-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev

s390/bp: remove s390_isolate_bp_guest()

2023-03-13T08:16:42+00:00

s390_isolate_bp_guest() is unused. Remove it.

Reviewed-by: Alexander Gordeev 
Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/bp: remove TIF_ISOLATE_BP

2023-03-13T08:16:42+00:00

TIF_ISOLATE_BP is unused since it was introduced with commit 6b73044b2b00
("s390: run user space and KVM guests with modified branch prediction").
Given that there is no use case remove it again.

Acked-by: Alexander Gordeev 
Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/cpufeature: rework to allow more than only hwcap bits

2022-07-19T14:18:49+00:00

Rework cpufeature implementation to allow for various cpu feature
indications, which is not only limited to hwcap bits. This is achieved
by adding a sequential list of cpu feature numbers, where each of them
is mapped to an entry which indicates what this number is about.

Each entry contains a type member, which indicates what feature
name space to look into (e.g. hwcap, or cpu facility). If wanted this
allows also to automatically load modules only in e.g. z/VM
configurations.

Signed-off-by: Heiko Carstens 
Signed-off-by: Steffen Eiden 
Reviewed-by: Claudio Imbrenda 
Reviewed-by: Hendrik Brueckner 
Link: https://lore.kernel.org/r/20220713125644.16121-2-seiden@linux.ibm.com
Signed-off-by: Alexander Gordeev

s390: add z16 elf platform

2022-04-06T11:08:50+00:00

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

Signed-off-by: Heiko Carstens

s390: raise minimum supported machine generation to z10

2022-03-10T14:58:17+00:00

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 
Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390: replace deprecated CPU-hotplug functions

2021-08-05T12:10:53+00:00

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 
Link: https://lore.kernel.org/r/20210803141621.780504-5-bigeasy@linutronix.de
Signed-off-by: Heiko Carstens

s390/hwcaps: make sie capability regular hwcap

2021-07-27T07:39:21+00:00

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

s390/hwcaps: remove hwcap stfle check

2021-07-27T07:39:21+00:00

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