linux.git/arch/s390/kernel/setup.c, branch v4.18

s390: add support for IBM z14 Model ZR1

2018-04-16T07:10:24+00:00

Just add the new machine type number to the two places that matter.

Cc:  # v4.14+
Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390: correct nospec auto detection init order

2018-04-11T15:46:00+00:00

With CONFIG_EXPOLINE_AUTO=y the call of spectre_v2_auto_early() via
early_initcall is done *after* the early_param functions. This
overwrites any settings done with the nobp/no_spectre_v2/spectre_v2
parameters. The code patching for the kernel is done after the
evaluation of the early parameters but before the early_initcall
is done. The end result is a kernel image that is patched correctly
but the kernel modules are not.

Make sure that the nospec auto detection function is called before the
early parameters are evaluated and before the code patching is done.

Fixes: 6e179d64126b ("s390: add automatic detection of the spectre defense")
Signed-off-by: Martin Schwidefsky

s390/setup : enable display support for KVM guest

2018-03-19T06:01:58+00:00

The S390 architecture does not support any graphics hardware,
but with the latest support for Virtio GPU in Linux and Virtio
GPU emulation in QEMU, it's possible to enable graphics for
S390 using the Virtio GPU device.

To enable display we need to enable the Linux Virtual Terminal (VT)
layer for S390. But the VT subsystem initializes quite early
at boot so we need a dummy console driver till the Virtio GPU
driver is initialized and we can run the framebuffer console.

The framebuffer console over a Virtio GPU device can be run
in combination with the serial SCLP console (default on S390).
The SCLP console can still be accessed by management applications
(eg: via Libvirt's virsh console).

Signed-off-by: Farhan Ali 
Acked-by: Christian Borntraeger 
Reviewed-by: Thomas Huth 
Message-Id: 
Signed-off-by: Christian Borntraeger 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Martin Schwidefsky

s390: unify linker symbols usage

2018-02-27T07:05:23+00:00

Common code defines linker symbols which denote sections start/end in
a form of char []. Referencing those symbols as _symbol or &_symbol
yields the same result, but "_symbol" form is more widespread across
newly written code. Convert s390 specific code to this style.

Also removes unused _text symbol definition in boot/compressed/misc.c.

Signed-off-by: Vasily Gorbik 
Acked-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390: introduce execute-trampolines for branches

2018-02-07T14:57:02+00:00

Add CONFIG_EXPOLINE to enable the use of the new -mindirect-branch= and
-mfunction_return= compiler options to create a kernel fortified against
the specte v2 attack.

With CONFIG_EXPOLINE=y all indirect branches will be issued with an
execute type instruction. For z10 or newer the EXRL instruction will
be used, for older machines the EX instruction. The typical indirect
call

	basr	%r14,%r1

is replaced with a PC relative call to a new thunk

	brasl	%r14,__s390x_indirect_jump_r1

The thunk contains the EXRL/EX instruction to the indirect branch

__s390x_indirect_jump_r1:
	exrl	0,0f
	j	.
0:	br	%r1

The detour via the execute type instruction has a performance impact.
To get rid of the detour the new kernel parameter "nospectre_v2" and
"spectre_v2=[on,off,auto]" can be used. If the parameter is specified
the kernel and module code will be patched at runtime.

Signed-off-by: Martin Schwidefsky

s390/alternative: use a copy of the facility bit mask

2018-02-05T12:49:16+00:00

To be able to switch off specific CPU alternatives with kernel parameters
make a copy of the facility bit mask provided by STFLE and use the copy
for the decision to apply an alternative.

Reviewed-by: David Hildenbrand 
Reviewed-by: Cornelia Huck 
Signed-off-by: Martin Schwidefsky

s390: kernel: add SPDX identifiers to the remaining files

2017-11-24T14:37:12+00:00

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the arch/s390/kernel/ files with the correct SPDX license
identifier based on the license text in the file itself.  The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Arnaldo Carvalho de Melo 
Cc: Alexander Shishkin 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Thomas Gleixner 
Cc: Kate Stewart 
Cc: Philippe Ombredanne 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Martin Schwidefsky

s390: simplify transactional execution elf hwcap handling

2017-11-09T15:54:30+00:00

Just use MACHINE_HAS_TE to decide if HWCAP_S390_TE needs
to be added to elf_hwcap.

Suggested-by: Dan Horák 
Reviewed-by: Christian Borntraeger 
Reviewed-by: Hendrik Brueckner 
Signed-off-by: Heiko Carstens

s390/virtio: remove unused header file kvm_virtio.h

2017-11-09T14:54:07+00:00

With commit 7fb2b2d51244 ("s390/virtio: remove the old KVM virtio
transport") the pre-ccw virtio transport for s390 was removed. To
complete the removal the uapi header file that contains the related data
structures must also be removed.

Signed-off-by: Christian Borntraeger 
Signed-off-by: Heiko Carstens

s390/nmi: allocation of the extended save area

2017-10-19T15:07:39+00:00

The machine check extended save area is needed to store the vector
registers and the guarded storage control block when a CPU is
interrupted by a machine check.

Move the slab cache allocation of the full save area to nmi.c,
for early boot use a static __initdata block.

Reviewed-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky