Add a boot message if either of the spectre defenses is active.
The message is
    "Spectre V2 mitigation: execute trampolines."
or  "Spectre V2 mitigation: limited branch prediction."
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Automatically decide between nobp vs. expolines if the spectre_v2=auto
kernel parameter is specified or CONFIG_EXPOLINE_AUTO=y is set.

The decision made at boot time due to CONFIG_EXPOLINE_AUTO=y being set
can be overruled with the nobp, nospec and spectre_v2 kernel parameters.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Keep the code for the nobp parameter handling with the code for
expolines. Both are related to the spectre v2 mitigation.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add support for format 3 channel path descriptors and use them to
gather utility strings.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Rename struct channel_path_desc to struct channel_path_desc_fmt0
to fit the scheme. Provide a macro for the function wrappers that
gather this and related data from firmware.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

It seems to be suboptimal to compress the entire image, so that we
could decompress and throw away the first 68k (0x11000) during the boot
process. This patch trims 0x11000 bytes during the build process and
adjusts symbols in size.h accordingly.

Besides making bzImage smaller, this change would also be a benefit
for kaslr. It allows to decompress the kernel right to desired offset,
without worrying about dead weight in front of the decompressed image.
Signed-off-by: NVasily Gorbik <gor@linux.vnet.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

A kernel crash occurs when the aes_s390 kernel module is
removed on machines < z14. This only happens on kernel
version 4.15 and higher on machines not supporting MSA 8.

The reason for the crash is a unconditional
crypto_unregister_aead() invocation where no previous
crypto_register_aead() had been called. The fix now
remembers if there has been a successful registration and
only then calls the unregister function upon kernel module
remove.

The code now crashing has been introduced with
"bf7fa038 s390/crypto: add s390 platform specific aes gcm support."
Signed-off-by: NHarald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

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: NFarhan Ali <alifm@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Message-Id: <e23b61f4f599ba23881727a1e8880e9d60cc6a48.1519315352.git.alifm@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

s/sene/sense
Signed-off-by: NJulian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Even though s390 compressed kernel support has been introduced long ago,
by default uncompressed kernel image is used by packaging targets like:
"make rpm-pkg", "make deb-pkg" as well as "make image_name".

At the same time "make install" would use compressed bzImage by default.
To avoid ambiguity, set bzImage as default image for packaging.
Signed-off-by: NVasily Gorbik <gor@linux.vnet.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

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: NVasily Gorbik <gor@linux.vnet.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Exception table (__ex_table section) is not used during the decompressor
phase and could be discarded to save the memory. It is currently
generated due to sclp_service_call function (sclp_early_core.c). An
assumption is that decompressor usage of sclp_service_call via
sclp_early_printk should never trigger exceptions.
Signed-off-by: NVasily Gorbik <gor@linux.vnet.ibm.com>
Acked-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

This function is checking for the suspend control, not the function
control.
Signed-off-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Make the behavior in case of constant IFCC/CCC errors configurable.
Add a sysfs attribute to switch between path disabled after threshold
exceeded (default) and message only.
Reviewed-by: NJan Hoeppner <hoeppner@linux.vnet.ibm.com>
Reviewed-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NStefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Provide base_asce_alloc() and base_asce_free() helper functions which
can be used to allocate an ASCE and all required region, segment and
page tables required to access memory regions of the virtual kernel
address space.

Both, the ASCE and all tables, do not use any features that correspond
to e.g. enhanced DAT features. This is required for some I/O functions
that pass an ASCE, like e.g. some service call requests, but which may
not use any enhanced features.
Acked-by: NPeter Oberparleiter <oberpar@linux.vnet.ibm.com>
Acked-by: NJanosch Frank <frankja@linux.vnet.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The system call path can be interrupted before the switch back to the
standard branch prediction with BPENTER has been done. The critical
section cleanup code skips forward to .Lsysc_do_svc and bypasses the
BPENTER. In this case the kernel and all subsequent code will run with
the limited branch prediction.

Fixes: eacf67eb9b32 ("s390: run user space and KVM guests with modified branch prediction")
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Commit f19fbd5e ("s390: introduce execute-trampolines for
branches") introduces .cfi_* assembler directives.  Instead of
using the directives directly, use the macros from asm/dwarf.h.
This also ensures that the dwarf debug information are created
in the .debug_frame section.

Fixes: f19fbd5e ("s390: introduce execute-trampolines for branches")
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

I've accidentally stumbled upon the IS_ENABLED(EXPOLINE_*) lines, which
obviously always evaluate to false. Fix this.

Fixes: f19fbd5e ("s390: introduce execute-trampolines for branches")
Signed-off-by: NEugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The ARCH_WANTS_PROT_NUMA_PROT_NONE symbol was removed by
commit 6a33979d ("mm: remove misleading ARCH_USES_NUMA_PROT_NONE"),
but S390 still selects it.

Remove the ARCH_WANTS_PROT_NUMA_PROT_NONE select from the S390 symbol.

Discovered with the
https://github.com/ulfalizer/Kconfiglib/blob/master/examples/list_undefined.py
script.
Signed-off-by: NUlf Magnusson <ulfalizer@gmail.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

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: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Define TIF_ISOLATE_BP and TIF_ISOLATE_BP_GUEST and add the necessary
plumbing in entry.S to be able to run user space and KVM guests with
limited branch prediction.

To switch a user space process to limited branch prediction the
s390_isolate_bp() function has to be call, and to run a vCPU of a KVM
guest associated with the current task with limited branch prediction
call s390_isolate_bp_guest().
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add the PPA instruction to the system entry and exit path to switch
the kernel to a different branch prediction behaviour. The instructions
are added via CPU alternatives and can be disabled with the "nospec"
or the "nobp=0" kernel parameter. If the default behaviour selected
with CONFIG_KERNEL_NOBP is set to "n" then the "nobp=1" parameter can be
used to enable the changed kernel branch prediction.
Acked-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

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: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add an optimized version of the array_index_mask_nospec function for
s390 based on a compare and a subtract with borrow.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Clear all user space registers on entry to the kernel and all KVM guest
registers on KVM guest exit if the register does not contain either a
parameter or a result value.
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add the signum system call parameter for documentation purposes only,
and without checking if the passed value is a valid real-time signal.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Remove %p because the kprobe will be dumped in dump_kprobe().
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The man page for the s390_runtime_instr() system call refers to a
header file that was never exported. Therefore it's time to finally
provide the header file, and move large parts of the runtime
instrumentation header file to a new uapi header file.
Reported-by: NEugene Syromyatnikov <evgsyr@gmail.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

With z14, the store system information instruction provides an
licensed internal code identifier.  Display it in /proc/sysinfo.

For more information, see the z/Architecture Principles of Operation.
(SA22-7832-11).
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Commit 2a842aca ("block: introduce new block status code type")
added blk_status_t usage to the eadm subchannel driver. However
blk_status_t is unknown when included via <linux/blkdev.h> for CONFIG_BLOCK=n.

Only include <linux/blk_types.h> since this is the only dependency eadm has.

This fixes build failures like below:
In file included from drivers/s390/cio/eadm_sch.c:24:0:
./arch/s390/include/asm/eadm.h:111:4: error: unknown type name 'blk_status_t'; did you mean 'si_status'?
    blk_status_t error);
Reported-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

It's required to avoid losing dirty and accessed bits.

Link: http://lkml.kernel.org/r/20171213105756.69879-8-kirill.shutemov@linux.intel.comSigned-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no need to have ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT, as all
the page initialization code is in common code.

Also, there is no need to depend on MEMORY_HOTPLUG, as initialization
code does not really use hotplug memory functionality.  So, we can
remove this requirement as well.

This patch allows to use deferred struct page initialization on all
platforms with memblock allocator.

Tested on x86, arm64, and sparc.  Also, verified that code compiles on
PPC with CONFIG_MEMORY_HOTPLUG disabled.

Link: http://lkml.kernel.org/r/20171117014601.31606-1-pasha.tatashin@oracle.comSigned-off-by: NPavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>	[s390]
Reviewed-by: NKhalid Aziz <khalid.aziz@oracle.com>
Acked-by: NMichael Ellerman <mpe@ellerman.id.au>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since we've changed div/mod exception handling for src_reg in
eBPF verifier itself, remove the leftovers from s390x JIT.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>

The patch modifies the previously defined GISA data structure to be
able to store two GISA formats, format-0 and format-1. Additionally,
it verifies the availability of the GISA format facility and enables
the use of a format-1 GISA in the SIE control block accordingly.

A format-1 can do everything that format-0 can and we will need it
for real HW passthrough. As there are systems with only format-0
we keep both variants.
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Acked-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The GISA format facility is required by the host to be able to process
a format-1 GISA. If not available, the used GISA format will be format-0.
All format-1 related extension will not be available in this case.
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NDavid Hildenbrand <david@redhat.com>
Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

If the AIV facility is available, a GISA will be used to manage emulated
adapter interrupts.
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The function returns a pending I/O interrupt with the highest
priority defined by its ISC.

Together with AIV activation, pending adapter interrupts are
managed by the GISA IPM. Thus kvm_s390_get_io_int() needs to
inspect the IPM as well when the interrupt with the highest
priority has to be identified.

In case classic and adapter interrupts with the same ISC are
pending, the classic interrupt will be returned first.
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Pending interrupts marked in the GISA IPM are required to
become part of the answer of ioctl KVM_DEV_FLIC_GET_ALL_IRQS.

The ioctl KVM_DEV_FLIC_ENQUEUE is already capable to enqueue
adapter interrupts when a GISA is present.

With ioctl KVM_DEV_FLIC_CLEAR_IRQS the GISA IPM wil be cleared
now as well.
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

The function isc_to_int_word() allows the generation of interruption
words for adapter interrupts.
Signed-off-by: NMichael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>