linux-toradex.git/arch/s390, branch v5.0

Merge tag 'kvm-s390-master-5.0' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-master

2019-02-20T22:48:55+00:00

KVM: s390: Fix crypto handling for nested KVM

s390: vsie: Use effective CRYCBD.31 to check CRYCBD validity

2019-02-11T12:19:20+00:00

When facility.76 MSAX3 is present for the guest we must issue a validity
interception if the CRYCBD is not valid.

The bit CRYCBD.31 is an effective field and tested at each guest level
and has for effect to mask the facility.76

It follows that if CRYCBD.31 is clear and AP is not in use  we do not
have to test the CRYCBD validatity even if facility.76 is present in the
host.

Fixes: 6ee74098201b ("KVM: s390: vsie: allow CRYCB FORMAT-0")
Cc: stable@vger.kernel.org

Signed-off-by: Pierre Morel 
Reported-by: Claudio Imbrenda 
Acked-by: David Hildenbrand 
Acked-by: Cornelia Huck 
Reviewed-by: Christian Borntraeger 
Message-Id: <1549876849-32680-1-git-send-email-pmorel@linux.ibm.com>
Signed-off-by: Christian Borntraeger

Revert "s390/pci: remove bit_lock usage in interrupt handler"

2019-02-07T10:56:29+00:00

This reverts commit 9594ca6b87d9f11e9f14ac31581e0e5d79a8e839.

With the handle_simple_irq irq_flow_handler it must be ensured to
not call generic_handle_irq with the same IRQ number on 2 CPUs at
the same time (interrupts are floating on s390).
Contrary to my initial investigation the irq_desc's lock usage in
handle_simple_irq does not ensure this. Thus re-introduce the bit-
lock usage in s390's pci handler.

Reported-by: Ursula Braun 
Reported-by: Alexander Schmidt 
Signed-off-by: Sebastian Ott 
Signed-off-by: Martin Schwidefsky

s390/suspend: fix stack setup in swsusp_arch_suspend

2019-01-28T14:43:17+00:00

The patch that added support for the virtually mapped kernel stacks changed
swsusp_arch_suspend to switch to the nodat-stack as the vmap stack is not
available while going in and out of suspend.

Unfortunately the switch to the nodat-stack is incorrect which breaks
suspend to disk.

Cc: stable@vger.kernel.org # v4.20
Fixes: ce3dc447493f ("s390: add support for virtually mapped kernel stacks")
Signed-off-by: Martin Schwidefsky

s390/smp: Fix calling smp_call_ipl_cpu() from ipl CPU

2019-01-11T16:12:03+00:00

When calling smp_call_ipl_cpu() from the IPL CPU, we will try to read
from pcpu_devices->lowcore. However, due to prefixing, that will result
in reading from absolute address 0 on that CPU. We have to go via the
actual lowcore instead.

This means that right now, we will read lc->nodat_stack == 0 and
therfore work on a very wrong stack.

This BUG essentially broke rebooting under QEMU TCG (which will report
a low address protection exception). And checking under KVM, it is
also broken under KVM. With 1 VCPU it can be easily triggered.

:/# echo 1 > /proc/sys/kernel/sysrq
:/# echo b > /proc/sysrq-trigger
[   28.476745] sysrq: SysRq : Resetting
[   28.476793] Kernel stack overflow.
[   28.476817] CPU: 0 PID: 424 Comm: sh Not tainted 5.0.0-rc1+ #13
[   28.476820] Hardware name: IBM 2964 NE1 716 (KVM/Linux)
[   28.476826] Krnl PSW : 0400c00180000000 0000000000115c0c (pcpu_delegate+0x12c/0x140)
[   28.476861]            R:0 T:1 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
[   28.476863] Krnl GPRS: ffffffffffffffff 0000000000000000 000000000010dff8 0000000000000000
[   28.476864]            0000000000000000 0000000000000000 0000000000ab7090 000003e0006efbf0
[   28.476864]            000000000010dff8 0000000000000000 0000000000000000 0000000000000000
[   28.476865]            000000007fffc000 0000000000730408 000003e0006efc58 0000000000000000
[   28.476887] Krnl Code: 0000000000115bfe: 4170f000            la      %r7,0(%r15)
[   28.476887]            0000000000115c02: 41f0a000            la      %r15,0(%r10)
[   28.476887]           #0000000000115c06: e370f0980024        stg     %r7,152(%r15)
[   28.476887]           >0000000000115c0c: c0e5fffff86e        brasl   %r14,114ce8
[   28.476887]            0000000000115c12: 41f07000            la      %r15,0(%r7)
[   28.476887]            0000000000115c16: a7f4ffa8            brc     15,115b66
[   28.476887]            0000000000115c1a: 0707                bcr     0,%r7
[   28.476887]            0000000000115c1c: 0707                bcr     0,%r7
[   28.476901] Call Trace:
[   28.476902] Last Breaking-Event-Address:
[   28.476920]  [<0000000000a01c4a>] arch_call_rest_init+0x22/0x80
[   28.476927] Kernel panic - not syncing: Corrupt kernel stack, can't continue.
[   28.476930] CPU: 0 PID: 424 Comm: sh Not tainted 5.0.0-rc1+ #13
[   28.476932] Hardware name: IBM 2964 NE1 716 (KVM/Linux)
[   28.476932] Call Trace:

Fixes: 2f859d0dad81 ("s390/smp: reduce size of struct pcpu")
Cc: stable@vger.kernel.org # 4.0+
Reported-by: Cornelia Huck 
Signed-off-by: David Hildenbrand 
Signed-off-by: Martin Schwidefsky

s390/vdso: correct vdso mapping for compat tasks

2019-01-11T16:12:02+00:00

While "s390/vdso: avoid 64-bit vdso mapping for compat tasks" fixed
64-bit vdso mapping for compat tasks under gdb it introduced another
problem. "compat_mm" flag is not inherited during fork and when
31-bit process forks a child (but does not perform exec) it ends up
with 64-bit vdso. To address that, init_new_context (which is called
during fork and exec) now initialize compat_mm based on thread TIF_31BIT
flag. Later compat_mm is adjusted in arch_setup_additional_pages, which
is called during exec.

Fixes: d1befa65823e ("s390/vdso: avoid 64-bit vdso mapping for compat tasks")
Reported-by: Stefan Liebler 
Reviewed-by: Heiko Carstens 
Cc:  # v4.20+
Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky

s390/smp: fix CPU hotplug deadlock with CPU rescan

2019-01-11T16:12:02+00:00

smp_rescan_cpus() is called without the device_hotplug_lock, which can lead
to a dedlock when a new CPU is found and immediately set online by a udev
rule.

This was observed on an older kernel version, where the cpu_hotplug_begin()
loop was still present, and it resulted in hanging chcpu and systemd-udev
processes. This specific deadlock will not show on current kernels. However,
there may be other possible deadlocks, and since smp_rescan_cpus() can still
trigger a CPU hotplug operation, the device_hotplug_lock should be held.

For reference, this was the deadlock with the old cpu_hotplug_begin() loop:

        chcpu (rescan)                       systemd-udevd

 echo 1 > /sys/../rescan
 -> smp_rescan_cpus()
 -> (*) get_online_cpus()
    (increases refcount)
 -> smp_add_present_cpu()
    (new CPU found)
 -> register_cpu()
 -> device_add()
 -> udev "add" event triggered -----------> udev rule sets CPU online
                                         -> echo 1 > /sys/.../online
                                         -> lock_device_hotplug_sysfs()
                                            (this is missing in rescan path)
                                         -> device_online()
                                         -> (**) device_lock(new CPU dev)
                                         -> cpu_up()
                                         -> cpu_hotplug_begin()
                                            (loops until refcount == 0)
                                            -> deadlock with (*)
 -> bus_probe_device()
 -> device_attach()
 -> device_lock(new CPU dev)
    -> deadlock with (**)

Fix this by taking the device_hotplug_lock in the CPU rescan path.

Cc: 
Signed-off-by: Gerald Schaefer 
Signed-off-by: Martin Schwidefsky

s390/mm: always force a load of the primary ASCE on context switch

2019-01-11T16:12:02+00:00

The ASCE of an mm_struct can be modified after a task has been created,
e.g. via crst_table_downgrade for a compat process. The active_mm logic
to avoid the switch_mm call if the next task is a kernel thread can
lead to a situation where switch_mm is called where 'prev == next' is
true but 'prev->context.asce == next->context.asce' is not.

This can lead to a situation where a CPU uses the outdated ASCE to run
a task. The result can be a crash, endless loops and really subtle
problem due to TLBs being created with an invalid ASCE.

Cc: stable@kernel.org # v3.15+
Fixes: 53e857f30867 ("s390/mm,tlb: race of lazy TLB flush vs. recreation")
Reported-by: Heiko Carstens 
Reviewed-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

s390/early: improve machine detection

2019-01-11T16:12:02+00:00

Right now the early machine detection code check stsi 3.2.2 for "KVM"
and set MACHINE_IS_VM if this is different. As the console detection
uses diagnose 8 if MACHINE_IS_VM returns true this will crash Linux
early for any non z/VM system that sets a different value than KVM.
So instead of assuming z/VM, do not set any of MACHINE_IS_LPAR,
MACHINE_IS_VM, or MACHINE_IS_KVM.

CC: stable@vger.kernel.org
Reviewed-by: Heiko Carstens 
Signed-off-by: Christian Borntraeger 
Signed-off-by: Martin Schwidefsky

Merge tag 'kbuild-v4.21-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2019-01-07T00:33:10+00:00

Pull more Kbuild updates from Masahiro Yamada:

 - improve boolinit.cocci and use_after_iter.cocci semantic patches

 - fix alignment for kallsyms

 - move 'asm goto' compiler test to Kconfig and clean up jump_label
   CONFIG option

 - generate asm-generic wrappers automatically if arch does not
   implement mandatory UAPI headers

 - remove redundant generic-y defines

 - misc cleanups

* tag 'kbuild-v4.21-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kconfig: rename generated .*conf-cfg to *conf-cfg
  kbuild: remove unnecessary stubs for archheader and archscripts
  kbuild: use assignment instead of define ... endef for filechk_* rules
  arch: remove redundant UAPI generic-y defines
  kbuild: generate asm-generic wrappers if mandatory headers are missing
  arch: remove stale comments "UAPI Header export list"
  riscv: remove redundant kernel-space generic-y
  kbuild: change filechk to surround the given command with { }
  kbuild: remove redundant target cleaning on failure
  kbuild: clean up rule_dtc_dt_yaml
  kbuild: remove UIMAGE_IN and UIMAGE_OUT
  jump_label: move 'asm goto' support test to Kconfig
  kallsyms: lower alignment on ARM
  scripts: coccinelle: boolinit: drop warnings on named constants
  scripts: coccinelle: check for redeclaration
  kconfig: remove unused "file" field of yylval union
  nds32: remove redundant kernel-space generic-y
  nios2: remove unneeded HAS_DMA define