8173 Commits

Author SHA1 Message Date
Eric W. Biederman
39a26d8721 exit: Add and use make_task_dead.
commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream.

There are two big uses of do_exit.  The first is it's design use to be
the guts of the exit(2) system call.  The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.

Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure.  In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.

Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.

As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:27:20 +01:00
Heiko Carstens
e15750aa28 KVM: s390: interrupt: use READ_ONCE() before cmpxchg()
[ Upstream commit 42400d99e9f0728c17240edb9645637ead40f6b9 ]

Use READ_ONCE() before cmpxchg() to prevent that the compiler generates
code that fetches the to be compared old value several times from memory.

Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20230109145456.2895385-1-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:27:18 +01:00
Alexander Gordeev
b1eb964d78 s390: expicitly align _edata and _end symbols on page boundary
[ Upstream commit 45d619bdaf799196d702a9ae464b07066d6db2f9 ]

Symbols _edata and _end in the linker script are the
only unaligned expicitly on page boundary. Although
_end is aligned implicitly by BSS_SECTION macro that
is still inconsistent and could lead to a bug if a tool
or function would assume that _edata is as aligned as
others.

For example, vmem_map_init() function does not align
symbols _etext, _einittext etc. Should these symbols
be unaligned as well, the size of ranges to update
were short on one page.

Instead of fixing every occurrence of this kind in the
code and external tools just force the alignment on
these two symbols.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:27:17 +01:00
Niklas Schnelle
fb45ec279b s390/debug: add _ASM_S390_ prefix to header guard
[ Upstream commit 0d4d52361b6c29bf771acd4fa461f06d78fb2fac ]

Using DEBUG_H without a prefix is very generic and inconsistent with
other header guards in arch/s390/include/asm. In fact it collides with
the same name in the ath9k wireless driver though that depends on !S390
via disabled wireless support. Let's just use a consistent header guard
name and prevent possible future trouble.

Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:27:17 +01:00
Heiko Carstens
798dfeeae3 s390/percpu: add READ_ONCE() to arch_this_cpu_to_op_simple()
commit e3f360db08d55a14112bd27454e616a24296a8b0 upstream.

Make sure that *ptr__ within arch_this_cpu_to_op_simple() is only
dereferenced once by using READ_ONCE(). Otherwise the compiler could
generate incorrect code.

Cc: <stable@vger.kernel.org>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:48:49 +01:00
Heiko Carstens
a400593eb3 s390/cpum_sf: add READ_ONCE() semantics to compare and swap loops
commit 82d3edb50a11bf3c5ef63294d5358ba230181413 upstream.

The current cmpxchg_double() loops within the perf hw sampling code do not
have READ_ONCE() semantics to read the old value from memory. This allows
the compiler to generate code which reads the "old" value several times
from memory, which again allows for inconsistencies.

For example:

        /* Reset trailer (using compare-double-and-swap) */
        do {
                te_flags = te->flags & ~SDB_TE_BUFFER_FULL_MASK;
                te_flags |= SDB_TE_ALERT_REQ_MASK;
        } while (!cmpxchg_double(&te->flags, &te->overflow,
                 te->flags, te->overflow,
                 te_flags, 0ULL));

The compiler could generate code where te->flags used within the
cmpxchg_double() call may be refetched from memory and which is not
necessarily identical to the previous read version which was used to
generate te_flags. Which in turn means that an incorrect update could
happen.

Fix this by adding READ_ONCE() semantics to all cmpxchg_double()
loops. Given that READ_ONCE() cannot generate code on s390 which atomically
reads 16 bytes, use a private compare-and-swap-double implementation to
achieve that.

Also replace cmpxchg_double() with the private implementation to be able to
re-use the old value within the loops.

As a side effect this converts the whole code to only use bit fields
to read and modify bits within the hws trailer header.

Reported-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/linux-s390/Y71QJBhNTIatvxUT@osiris/T/#ma14e2a5f7aa8ed4b94b6f9576799b3ad9c60f333
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:48:49 +01:00
Alexander Egorenkov
8400b91c11 s390/kexec: fix ipl report address for kdump
commit c2337a40e04dde1692b5b0a46ecc59f89aaba8a1 upstream.

This commit addresses the following erroneous situation with file-based
kdump executed on a system with a valid IPL report.

On s390, a kdump kernel, its initrd and IPL report if present are loaded
into a special and reserved on boot memory region - crashkernel. When
a system crashes and kdump was activated before, the purgatory code
is entered first which swaps the crashkernel and [0 - crashkernel size]
memory regions. Only after that the kdump kernel is entered. For this
reason, the pointer to an IPL report in lowcore must point to the IPL report
after the swap and not to the address of the IPL report that was located in
crashkernel memory region before the swap. Failing to do so, makes the
kdump's decompressor try to read memory from the crashkernel memory region
which already contains the production's kernel memory.

The situation described above caused spontaneous kdump failures/hangs
on systems where the Secure IPL is activated because on such systems
an IPL report is always present. In that case kdump's decompressor tried
to parse an IPL report which frequently lead to illegal memory accesses
because an IPL report contains addresses to various data.

Cc: <stable@vger.kernel.org>
Fixes: 99feaa717e55 ("s390/kexec_file: Create ipl report and pass to next kernel")
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:48:48 +01:00
Thomas Huth
f6550976fe KVM: s390: vsie: Fix the initialization of the epoch extension (epdx) field
commit 0dd4cdccdab3d74bd86b868768a7dca216bcce7e upstream.

We recently experienced some weird huge time jumps in nested guests when
rebooting them in certain cases. After adding some debug code to the epoch
handling in vsie.c (thanks to David Hildenbrand for the idea!), it was
obvious that the "epdx" field (the multi-epoch extension) did not get set
to 0xff in case the "epoch" field was negative.
Seems like the code misses to copy the value from the epdx field from
the guest to the shadow control block. By doing so, the weird time
jumps are gone in our scenarios.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=2140899
Fixes: 8fa1696ea781 ("KVM: s390: Multiple Epoch Facility support")
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Cc: stable@vger.kernel.org # 4.19+
Link: https://lore.kernel.org/r/20221123090833.292938-1-thuth@redhat.com
Message-Id: <20221123090833.292938-1-thuth@redhat.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-14 11:37:20 +01:00
Heiko Carstens
5fefdceafb s390/crashdump: fix TOD programmable field size
[ Upstream commit f44e07a8afdd713ddc1a8832c39372fe5dd86895 ]

The size of the TOD programmable field was incorrectly increased from
four to eight bytes with commit 1a2c5840acf9 ("s390/dump: cleanup CPU
save area handling").
This leads to an elf notes section NT_S390_TODPREG which has a size of
eight instead of four bytes in case of kdump, however even worse is
that the contents is incorrect: it is supposed to contain only the
contents of the TOD programmable field, but in fact contains a mix of
the TOD programmable field (32 bit upper bits) and parts of the CPU
timer register (lower 32 bits).

Fix this by simply changing the size of the todpreg field within the
save area structure. This will implicitly also fix the size of the
corresponding elf notes sections.

This also gets rid of this compile time warning:

in function ‘fortify_memcpy_chk’,
    inlined from ‘save_area_add_regs’ at arch/s390/kernel/crash_dump.c:99:2:
./include/linux/fortify-string.h:413:25: error: call to ‘__read_overflow2_field’
   declared with attribute warning: detected read beyond size of field
   (2nd parameter); maybe use struct_group()? [-Werror=attribute-warning]
  413 |                         __read_overflow2_field(q_size_field, size);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 1a2c5840acf9 ("s390/dump: cleanup CPU save area handling")
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-02 17:41:07 +01:00
Nico Boehr
119407dc32 KVM: s390: pv: don't allow userspace to set the clock under PV
[ Upstream commit 6973091d1b50ab4042f6a2d495f59e9db3662ab8 ]

When running under PV, the guest's TOD clock is under control of the
ultravisor and the hypervisor isn't allowed to change it. Hence, don't
allow userspace to change the guest's TOD clock by returning
-EOPNOTSUPP.

When userspace changes the guest's TOD clock, KVM updates its
kvm.arch.epoch field and, in addition, the epoch field in all state
descriptions of all VCPUs.

But, under PV, the ultravisor will ignore the epoch field in the state
description and simply overwrite it on next SIE exit with the actual
guest epoch. This leads to KVM having an incorrect view of the guest's
TOD clock: it has updated its internal kvm.arch.epoch field, but the
ultravisor ignores the field in the state description.

Whenever a guest is now waiting for a clock comparator, KVM will
incorrectly calculate the time when the guest should wake up, possibly
causing the guest to sleep for much longer than expected.

With this change, kvm_s390_set_tod() will now take the kvm->lock to be
able to call kvm_s390_pv_is_protected(). Since kvm_s390_set_tod_clock()
also takes kvm->lock, use __kvm_s390_set_tod_clock() instead.

The function kvm_s390_set_tod_clock is now unused, hence remove it.
Update the documentation to indicate the TOD clock attr calls can now
return -EOPNOTSUPP.

Fixes: 0f3035047140 ("KVM: s390: protvirt: Do only reset registers that are accessible")
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20221011160712.928239-2-nrb@linux.ibm.com
Message-Id: <20221011160712.928239-2-nrb@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-16 09:58:17 +01:00
Peter Oberparleiter
c64be93f1e s390/boot: add secure boot trailer
[ Upstream commit aa127a069ef312aca02b730d5137e1778d0c3ba7 ]

This patch enhances the kernel image adding a trailer as required for
secure boot by future firmware versions.

Cc: <stable@vger.kernel.org> # 5.2+
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-10 18:15:32 +01:00
Heiko Carstens
1cdaca8f00 s390/uaccess: add missing EX_TABLE entries to __clear_user()
[ Upstream commit 4e1b5a86a5edfbefc9396d41b0fc1a2ebd0101b6 ]

For some exception types the instruction address points behind the
instruction that caused the exception. Take that into account and add
the missing exception table entries.

Cc: <stable@vger.kernel.org>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-10 18:15:32 +01:00
Heiko Carstens
b32b766be4 s390/pci: add missing EX_TABLE entries to __pcistg_mio_inuser()/__pcilg_mio_inuser()
commit 6ec803025cf3173a57222e4411097166bd06fa98 upstream.

For some exception types the instruction address points behind the
instruction that caused the exception. Take that into account and add
the missing exception table entry.

Cc: <stable@vger.kernel.org>
Fixes: f058599e22d5 ("s390/pci: Fix s390_mmio_read/write with MIO")
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-03 23:59:13 +09:00
Heiko Carstens
1ad7213fcf s390/futex: add missing EX_TABLE entry to __futex_atomic_op()
commit a262d3ad6a433e4080cecd0a8841104a5906355e upstream.

For some exception types the instruction address points behind the
instruction that caused the exception. Take that into account and add
the missing exception table entry.

Cc: <stable@vger.kernel.org>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-03 23:59:13 +09:00
Alexander Gordeev
4b198c41d7 s390/boot: fix absolute zero lowcore corruption on boot
[ Upstream commit 12dd19c159659ec9050f45dc8a2ff3c3917f4be3 ]

Crash dump always starts on CPU0. In case CPU0 is offline the
prefix page is not installed and the absolute zero lowcore is
used. However, struct lowcore::mcesad is never assigned and
stays zero. That leads to __machine_kdump() -> save_vx_regs()
call silently stores vector registers to the absolute lowcore
at 0x11b0 offset.

Fixes: a62bc0739253 ("s390/kdump: add support for vector extension")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-15 11:30:07 +02:00
Josh Poimboeuf
4e22a43ec7 s390: fix nospec table alignments
commit c9305b6c1f52060377c72aebe3a701389e9f3172 upstream.

Add proper alignment for .nospec_call_table and .nospec_return_table in
vmlinux.

[hca@linux.ibm.com]: The problem with the missing alignment of the nospec
tables exist since a long time, however only since commit e6ed91fd0768
("s390/alternatives: remove padding generation code") and with
CONFIG_RELOCATABLE=n the kernel may also crash at boot time.

The above named commit reduced the size of struct alt_instr by one byte,
so its new size is 11 bytes. Therefore depending on the number of cpu
alternatives the size of the __alt_instructions array maybe odd, which
again also causes that the addresses of the nospec tables will be odd.

If the address of __nospec_call_start is odd and the kernel is compiled
With CONFIG_RELOCATABLE=n the compiler may generate code that loads the
address of __nospec_call_start with a 'larl' instruction.

This will generate incorrect code since the 'larl' instruction only works
with even addresses. In result the members of the nospec tables will be
accessed with an off-by-one offset, which subsequently may lead to
addressing exceptions within __nospec_revert().

Fixes: f19fbd5ed642 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/8719bf1ce4a72ebdeb575200290094e9ce047bcc.1661557333.git.jpoimboe@kernel.org
Cc: <stable@vger.kernel.org> # 4.16
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-08 12:28:07 +02:00
Gerald Schaefer
047a4d0f79 s390/hugetlb: fix prepare_hugepage_range() check for 2 GB hugepages
commit 7c8d42fdf1a84b1a0dd60d6528309c8ec127e87c upstream.

The alignment check in prepare_hugepage_range() is wrong for 2 GB
hugepages, it only checks for 1 MB hugepage alignment.

This can result in kernel crash in __unmap_hugepage_range() at the
BUG_ON(start & ~huge_page_mask(h)) alignment check, for mappings
created with MAP_FIXED at unaligned address.

Fix this by correctly handling multiple hugepage sizes, similar to the
generic version of prepare_hugepage_range().

Fixes: d08de8e2d867 ("s390/mm: add support for 2GB hugepages")
Cc: <stable@vger.kernel.org> # 4.8+
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-08 12:28:07 +02:00
Juergen Gross
a7ada93971 s390/hypfs: avoid error message under KVM
[ Upstream commit 7b6670b03641ac308aaa6fa2e6f964ac993b5ea3 ]

When booting under KVM the following error messages are issued:

hypfs.7f5705: The hardware system does not support hypfs
hypfs.7a79f0: Initialization of hypfs failed with rc=-61

Demote the severity of first message from "error" to "info" and issue
the second message only in other error cases.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20220620094534.18967-1-jgross@suse.com
[arch/s390/hypfs/hypfs_diag.c changed description]
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-05 10:30:11 +02:00
Brian Foster
8195e065ab s390: fix double free of GS and RI CBs on fork() failure
commit 13cccafe0edcd03bf1c841de8ab8a1c8e34f77d9 upstream.

The pointers for guarded storage and runtime instrumentation control
blocks are stored in the thread_struct of the associated task. These
pointers are initially copied on fork() via arch_dup_task_struct()
and then cleared via copy_thread() before fork() returns. If fork()
happens to fail after the initial task dup and before copy_thread(),
the newly allocated task and associated thread_struct memory are
freed via free_task() -> arch_release_task_struct(). This results in
a double free of the guarded storage and runtime info structs
because the fields in the failed task still refer to memory
associated with the source task.

This problem can manifest as a BUG_ON() in set_freepointer() (with
CONFIG_SLAB_FREELIST_HARDENED enabled) or KASAN splat (if enabled)
when running trinity syscall fuzz tests on s390x. To avoid this
problem, clear the associated pointer fields in
arch_dup_task_struct() immediately after the new task is copied.
Note that the RI flag is still cleared in copy_thread() because it
resides in thread stack memory and that is where stack info is
copied.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Fixes: 8d9047f8b967c ("s390/runtime instrumentation: simplify task exit handling")
Fixes: 7b83c6297d2fc ("s390/guarded storage: simplify task exit handling")
Cc: <stable@vger.kernel.org> # 4.15
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20220816155407.537372-1-bfoster@redhat.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-31 17:16:48 +02:00
Gerald Schaefer
9227599cd9 s390/mm: do not trigger write fault when vma does not allow VM_WRITE
commit 41ac42f137080bc230b5882e3c88c392ab7f2d32 upstream.

For non-protection pXd_none() page faults in do_dat_exception(), we
call do_exception() with access == (VM_READ | VM_WRITE | VM_EXEC).
In do_exception(), vma->vm_flags is checked against that before
calling handle_mm_fault().

Since commit 92f842eac7ee3 ("[S390] store indication fault optimization"),
we call handle_mm_fault() with FAULT_FLAG_WRITE, when recognizing that
it was a write access. However, the vma flags check is still only
checking against (VM_READ | VM_WRITE | VM_EXEC), and therefore also
calling handle_mm_fault() with FAULT_FLAG_WRITE in cases where the vma
does not allow VM_WRITE.

Fix this by changing access check in do_exception() to VM_WRITE only,
when recognizing write access.

Link: https://lkml.kernel.org/r/20220811103435.188481-3-david@redhat.com
Fixes: 92f842eac7ee3 ("[S390] store indication fault optimization")
Cc: <stable@vger.kernel.org>
Reported-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-31 17:16:48 +02:00
Alexander Gordeev
276e1cac80 Revert "s390/smp: enforce lowcore protection on CPU restart"
commit 953503751a426413ea8aee2299ae3ee971b70d9b upstream.

This reverts commit 6f5c672d17f583b081e283927f5040f726c54598.

This breaks normal crash dump when CPU0 is offline.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-17 14:24:30 +02:00
Michal Suchanek
779fd8cb62 kexec, KEYS, s390: Make use of built-in and secondary keyring for signature verification
[ Upstream commit 0828c4a39be57768b8788e8cbd0d84683ea757e5 ]

commit e23a8020ce4e ("s390/kexec_file: Signature verification prototype")
adds support for KEXEC_SIG verification with keys from platform keyring
but the built-in keys and secondary keyring are not used.

Add support for the built-in keys and secondary keyring as x86 does.

Fixes: e23a8020ce4e ("s390/kexec_file: Signature verification prototype")
Cc: stable@vger.kernel.org
Cc: Philipp Rudo <prudo@linux.ibm.com>
Cc: kexec@lists.infradead.org
Cc: keyrings@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: "Lee, Chun-Yi" <jlee@suse.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:24:23 +02:00
Alexander Gordeev
9536d5451c s390/smp: enforce lowcore protection on CPU restart
[ Upstream commit 6f5c672d17f583b081e283927f5040f726c54598 ]

As result of commit 915fea04f932 ("s390/smp: enable DAT before
CPU restart callback is called") the low-address protection bit
gets mistakenly unset in control register 0 save area of the
absolute zero memory. That area is used when manual PSW restart
happened to hit an offline CPU. In this case the low-address
protection for that CPU will be dropped.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Fixes: 915fea04f932 ("s390/smp: enable DAT before CPU restart callback is called")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:24:13 +02:00
Alexander Gordeev
70caac180f s390/maccess: rework absolute lowcore accessors
[ Upstream commit ed0192bc644f3553d64a5cb461bdd0b1fbae3fdf ]

Macro mem_assign_absolute() is able to access the whole memory, but
is only used and makes sense when updating the absolute lowcore.
Instead, introduce get_abs_lowcore() and put_abs_lowcore() macros
that limit access to absolute lowcore addresses only.

Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:24:13 +02:00
Alexander Gordeev
ac0a3e2131 s390/smp: cleanup control register update routines
[ Upstream commit 9097fc793f74ef9c677f8c4aed0c24f6f07f0133 ]

Get rid of duplicate code and redundant data.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:24:12 +02:00
Alexander Gordeev
a002b86412 s390/smp: cleanup target CPU callback starting
[ Upstream commit dc2ab23b992c9d5dab93b9bf01b10b10465e537e ]

Macro mem_assign_absolute() is used to initialize a target
CPU lowcore callback parameters. But despite the macro name
it writes to the absolute lowcore only if the target CPU is
offline. In case the CPU is online the macro does implicitly
write to the normal memory.

That behaviour is correct, but extremely subtle. Sacrifice
few program bits in favour of clarity and distinguish between
online vs offline CPUs and normal vs absolute lowcore pointer.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:24:12 +02:00
Alexander Gordeev
9287df4362 s390/dump: fix os_info virtual vs physical address confusion
[ Upstream commit 9de209c7d584d6e06ad92f120d83d4f27c200497 ]

Due to historical reasons os_info handling functions misuse
the notion of physical vs virtual addresses difference.

Note: this does not fix a bug currently, since virtual
and physical addresses are identical.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:24:12 +02:00
Alexander Gordeev
f1415771f6 s390/crash: fix incorrect number of bytes to copy to user space
[ Upstream commit f6749da17a34eb08c9665f072ce7c812ff68aad2 ]

The number of bytes in a chunk is correctly calculated, but instead
the total number of bytes is passed to copy_to_user_real() function.

Reported-by: Matthew Wilcox <willy@infradead.org>
Fixes: df9694c7975f ("s390/dump: streamline oldmem copy functions")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:24:10 +02:00
Alexander Gordeev
2165fd2bae s390/maccess: fix semantics of memcpy_real() and its callers
[ Upstream commit 303fd988ed644c7daa260410f3ac99266573557d ]

There is a confusion with regard to the source address of
memcpy_real() and calling functions. While the declared
type for a source assumes a virtual address, in fact it
always called with physical address of the source.

This confusion led to bugs in copy_oldmem_kernel() and
copy_oldmem_user() functions, where __pa() macro applied
mistakenly to physical addresses. It does not lead to a
real issue, since virtual and physical addresses are
currently the same.

Fix both the bugs and memcpy_real() prototype by making
type of source address consistent to the function name
and the way it actually used.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:24:09 +02:00
Alexander Gordeev
ceea1bc153 s390/dump: fix old lowcore virtual vs physical address confusion
[ Upstream commit dc306186a130c6d9feb0aabc1c71b8ed1674a3bf ]

Virtual addresses of vmcore_info and os_info members are
wrongly passed to copy_oldmem_kernel(), while the function
expects physical address of the source. Instead, __pa()
macro should have been applied.

Yet, use of __pa() macro could be somehow confusing, since
copy_oldmem_kernel() may treat the source as an offset, not
as a direct physical address (that depens from the oldmem
availability and location).

Fix the virtual vs physical address confusion and make the
way the old lowcore is read consistent across all sources.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:24:09 +02:00
Claudio Imbrenda
81ea65c9ae KVM: s390: pv: leak the topmost page table when destroy fails
[ Upstream commit faa2f72cb3569256480c5540d242c84e99965160 ]

Each secure guest must have a unique ASCE (address space control
element); we must avoid that new guests use the same page for their
ASCE, to avoid errors.

Since the ASCE mostly consists of the address of the topmost page table
(plus some flags), we must not return that memory to the pool unless
the ASCE is no longer in use.

Only a successful Destroy Secure Configuration UVC will make the ASCE
reusable again.

If the Destroy Configuration UVC fails, the ASCE cannot be reused for a
secure guest (either for the ASCE or for other memory areas). To avoid
a collision, it must not be used again. This is a permanent error and
the page becomes in practice unusable, so we set it aside and leak it.
On failure we already leak other memory that belongs to the ultravisor
(i.e. the variable and base storage for a guest) and not leaking the
topmost page table was an oversight.

This error (and thus the leakage) should not happen unless the hardware
is broken or KVM has some unknown serious bug.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Fixes: 29b40f105ec8d55 ("KVM: s390: protvirt: Add initial vm and cpu lifecycle handling")
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20220628135619.32410-2-imbrenda@linux.ibm.com
Message-Id: <20220628135619.32410-2-imbrenda@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17 14:23:51 +02:00
Nico Boehr
aeb4c3e1c4 KVM: s390: pv: don't present the ecall interrupt twice
commit c3f0e5fd2d33d80c5a5a8b5e5d2bab2841709cc8 upstream.

When the SIGP interpretation facility is present and a VCPU sends an
ecall to another VCPU in enabled wait, the sending VCPU receives a 56
intercept (partial execution), so KVM can wake up the receiving CPU.
Note that the SIGP interpretation facility will take care of the
interrupt delivery and KVM's only job is to wake the receiving VCPU.

For PV, the sending VCPU will receive a 108 intercept (pv notify) and
should continue like in the non-PV case, i.e. wake the receiving VCPU.

For PV and non-PV guests the interrupt delivery will occur through the
SIGP interpretation facility on SIE entry when SIE finds the X bit in
the status field set.

However, in handle_pv_notification(), there was no special handling for
SIGP, which leads to interrupt injection being requested by KVM for the
next SIE entry. This results in the interrupt being delivered twice:
once by the SIGP interpretation facility and once by KVM through the
IICTL.

Add the necessary special handling in handle_pv_notification(), similar
to handle_partial_execution(), which simply wakes the receiving VCPU and
leave interrupt delivery to the SIGP interpretation facility.

In contrast to external calls, emergency calls are not interpreted but
also cause a 108 intercept, which is why we still need to call
handle_instruction() for SIGP orders other than ecall.

Since kvm_s390_handle_sigp_pei() is now called for all SIGP orders which
cause a 108 intercept - even if they are actually handled by
handle_instruction() - move the tracepoint in kvm_s390_handle_sigp_pei()
to avoid possibly confusing trace messages.

Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 5.7
Fixes: da24a0cc58ed ("KVM: s390: protvirt: Instruction emulation")
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20220718130434.73302-1-nrb@linux.ibm.com
Message-Id: <20220718130434.73302-1-nrb@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-17 14:22:48 +02:00
Harald Freudenberger
8bd9747d30 s390/archrandom: prevent CPACF trng invocations in interrupt context
commit 918e75f77af7d2e049bb70469ec0a2c12782d96a upstream.

This patch slightly reworks the s390 arch_get_random_seed_{int,long}
implementation: Make sure the CPACF trng instruction is never
called in any interrupt context. This is done by adding an
additional condition in_task().

Justification:

There are some constrains to satisfy for the invocation of the
arch_get_random_seed_{int,long}() functions:
- They should provide good random data during kernel initialization.
- They should not be called in interrupt context as the TRNG
  instruction is relatively heavy weight and may for example
  make some network loads cause to timeout and buck.

However, it was not clear what kind of interrupt context is exactly
encountered during kernel init or network traffic eventually calling
arch_get_random_seed_long().

After some days of investigations it is clear that the s390
start_kernel function is not running in any interrupt context and
so the trng is called:

Jul 11 18:33:39 t35lp54 kernel:  [<00000001064e90ca>] arch_get_random_seed_long.part.0+0x32/0x70
Jul 11 18:33:39 t35lp54 kernel:  [<000000010715f246>] random_init+0xf6/0x238
Jul 11 18:33:39 t35lp54 kernel:  [<000000010712545c>] start_kernel+0x4a4/0x628
Jul 11 18:33:39 t35lp54 kernel:  [<000000010590402a>] startup_continue+0x2a/0x40

The condition in_task() is true and the CPACF trng provides random data
during kernel startup.

The network traffic however, is more difficult. A typical call stack
looks like this:

Jul 06 17:37:07 t35lp54 kernel:  [<000000008b5600fc>] extract_entropy.constprop.0+0x23c/0x240
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b560136>] crng_reseed+0x36/0xd8
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b5604b8>] crng_make_state+0x78/0x340
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b5607e0>] _get_random_bytes+0x60/0xf8
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b56108a>] get_random_u32+0xda/0x248
Jul 06 17:37:07 t35lp54 kernel:  [<000000008aefe7a8>] kfence_guarded_alloc+0x48/0x4b8
Jul 06 17:37:07 t35lp54 kernel:  [<000000008aeff35e>] __kfence_alloc+0x18e/0x1b8
Jul 06 17:37:07 t35lp54 kernel:  [<000000008aef7f10>] __kmalloc_node_track_caller+0x368/0x4d8
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b611eac>] kmalloc_reserve+0x44/0xa0
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b611f98>] __alloc_skb+0x90/0x178
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b6120dc>] __napi_alloc_skb+0x5c/0x118
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b8f06b4>] qeth_extract_skb+0x13c/0x680
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b8f6526>] qeth_poll+0x256/0x3f8
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b63d76e>] __napi_poll.constprop.0+0x46/0x2f8
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b63dbec>] net_rx_action+0x1cc/0x408
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b937302>] __do_softirq+0x132/0x6b0
Jul 06 17:37:07 t35lp54 kernel:  [<000000008abf46ce>] __irq_exit_rcu+0x13e/0x170
Jul 06 17:37:07 t35lp54 kernel:  [<000000008abf531a>] irq_exit_rcu+0x22/0x50
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b922506>] do_io_irq+0xe6/0x198
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b935826>] io_int_handler+0xd6/0x110
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b9358a6>] psw_idle_exit+0x0/0xa
Jul 06 17:37:07 t35lp54 kernel: ([<000000008ab9c59a>] arch_cpu_idle+0x52/0xe0)
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b933cfe>] default_idle_call+0x6e/0xd0
Jul 06 17:37:07 t35lp54 kernel:  [<000000008ac59f4e>] do_idle+0xf6/0x1b0
Jul 06 17:37:07 t35lp54 kernel:  [<000000008ac5a28e>] cpu_startup_entry+0x36/0x40
Jul 06 17:37:07 t35lp54 kernel:  [<000000008abb0d90>] smp_start_secondary+0x148/0x158
Jul 06 17:37:07 t35lp54 kernel:  [<000000008b935b9e>] restart_int_handler+0x6e/0x90

which confirms that the call is in softirq context. So in_task() covers exactly
the cases where we want to have CPACF trng called: not in nmi, not in hard irq,
not in soft irq but in normal task context and during kernel init.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Link: https://lore.kernel.org/r/20220713131721.257907-1-freude@linux.ibm.com
Fixes: e4f74400308c ("s390/archrandom: simplify back to earlier design and initialize earlier")
[agordeev@linux.ibm.com changed desc, added Fixes and Link, removed -stable]
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-03 12:03:42 +02:00
Claudio Imbrenda
31c60d15cc KVM: s390x: fix SCK locking
[ Upstream commit c0573ba5c5a2244dc02060b1f374d4593c1d20b7 ]

When handling the SCK instruction, the kvm lock is taken, even though
the vcpu lock is already being held. The normal locking order is kvm
lock first and then vcpu lock. This is can (and in some circumstances
does) lead to deadlocks.

The function kvm_s390_set_tod_clock is called both by the SCK handler
and by some IOCTLs to set the clock. The IOCTLs will not hold the vcpu
lock, so they can safely take the kvm lock. The SCK handler holds the
vcpu lock, but will also somehow need to acquire the kvm lock without
relinquishing the vcpu lock.

The solution is to factor out the code to set the clock, and provide
two wrappers. One is called like the original function and does the
locking, the other is called kvm_s390_try_set_tod_clock and uses
trylock to try to acquire the kvm lock. This new wrapper is then used
in the SCK handler. If locking fails, -EAGAIN is returned, which is
eventually propagated to userspace, thus also freeing the vcpu lock and
allowing for forward progress.

This is not the most efficient or elegant way to solve this issue, but
the SCK instruction is deprecated and its performance is not critical.

The goal of this patch is just to provide a simple but correct way to
fix the bug.

Fixes: 6a3f95a6b04c ("KVM: s390: Intercept SCK instruction")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Link: https://lore.kernel.org/r/20220301143340.111129-1-imbrenda@linux.ibm.com
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-07-12 16:35:02 +02:00
Alexander Egorenkov
a29c71f3a4 s390/setup: preserve memory at OLDMEM_BASE and OLDMEM_SIZE
[ Upstream commit 6b4b54c7ca347bcb4aa7a3cc01aa16e84ac7fbe4 ]

We need to preserve the values at OLDMEM_BASE and OLDMEM_SIZE which are
used by zgetdump in case when kdump crashes. In that case zgetdump will
attempt to read OLDMEM_BASE and OLDMEM_SIZE in order to find out where
the memory range [0 - OLDMEM_SIZE] belonging to the production kernel is.

Fixes: f1a546947431 ("s390/setup: don't reserve memory that occupied decompressor's head")
Cc: stable@vger.kernel.org # 5.15+
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-07-12 16:34:56 +02:00
Alexander Gordeev
06de5cf615 s390/setup: use physical pointers for memblock_reserve()
[ Upstream commit 04f11ed7d8e018e1f01ebda5814ddfeb3a1e6ae1 ]

memblock_reserve() function accepts physcal address of a memory
block to be reserved, but provided with virtual memory pointers.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-07-12 16:34:56 +02:00
Alexander Gordeev
6ed826c949 s390/boot: allocate amode31 section in decompressor
[ Upstream commit e3ec8e0f5711d73f7e5d5c3cffdf4fad4f1487b9 ]

The memory for amode31 section is allocated from the decompressed
kernel. Instead, allocate that memory from the decompressor. This
is a prerequisite to allow initialization of the virtual memory
before the decompressed kernel takes over.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-07-12 16:34:56 +02:00
Masahiro Yamada
a6c5c65f4c s390: remove unneeded 'select BUILD_BIN2C'
commit 25deecb21c18ee29e3be8ac6177b2a9504c33d2d upstream.

Since commit 4c0f032d4963 ("s390/purgatory: Omit use of bin2c"),
s390 builds the purgatory without using bin2c.

Remove 'select BUILD_BIN2C' to avoid the unneeded build of bin2c.

Fixes: 4c0f032d4963 ("s390/purgatory: Omit use of bin2c")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20220613170902.1775211-1-masahiroy@kernel.org
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-07 17:53:27 +02:00
Jason A. Donenfeld
0222575395 s390/archrandom: simplify back to earlier design and initialize earlier
commit e4f74400308cb8abde5fdc9cad609c2aba32110c upstream.

s390x appears to present two RNG interfaces:
- a "TRNG" that gathers entropy using some hardware function; and
- a "DRBG" that takes in a seed and expands it.

Previously, the TRNG was wired up to arch_get_random_{long,int}(), but
it was observed that this was being called really frequently, resulting
in high overhead. So it was changed to be wired up to arch_get_random_
seed_{long,int}(), which was a reasonable decision. Later on, the DRBG
was then wired up to arch_get_random_{long,int}(), with a complicated
buffer filling thread, to control overhead and rate.

Fortunately, none of the performance issues matter much now. The RNG
always attempts to use arch_get_random_seed_{long,int}() first, which
means a complicated implementation of arch_get_random_{long,int}() isn't
really valuable or useful to have around. And it's only used when
reseeding, which means it won't hit the high throughput complications
that were faced before.

So this commit returns to an earlier design of just calling the TRNG in
arch_get_random_seed_{long,int}(), and returning false in arch_get_
random_{long,int}().

Part of what makes the simplification possible is that the RNG now seeds
itself using the TRNG at bootup. But this only works if the TRNG is
detected early in boot, before random_init() is called. So this commit
also causes that check to happen in setup_arch().

Cc: stable@vger.kernel.org
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Ingo Franzki <ifranzki@linux.ibm.com>
Cc: Juergen Christ <jchrist@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20220610222023.378448-1-Jason@zx2c4.com
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-07 17:53:24 +02:00
Thomas Richter
ff3e50ca92 s390/cpumf: Handle events cycles and instructions identical
[ Upstream commit be857b7f77d130dbbd47c91fc35198b040f35865 ]

Events CPU_CYCLES and INSTRUCTIONS can be submitted with two different
perf_event attribute::type values:
 - PERF_TYPE_HARDWARE: when invoked via perf tool predefined events name
   cycles or cpu-cycles or instructions.
 - pmu->type: when invoked via perf tool event name cpu_cf/CPU_CYLCES/ or
   cpu_cf/INSTRUCTIONS/. This invocation also selects the PMU to which
   the event belongs.
Handle both type of invocations identical for events CPU_CYLCES and
INSTRUCTIONS. They address the same hardware.
The result is different when event modifier exclude_kernel is also set.
Invocation with event modifier for user space event counting fails.

Output before:

 # perf stat -e cpum_cf/cpu_cycles/u -- true

 Performance counter stats for 'true':

   <not supported>      cpum_cf/cpu_cycles/u

       0.000761033 seconds time elapsed

       0.000076000 seconds user
       0.000725000 seconds sys

 #

Output after:
 # perf stat -e cpum_cf/cpu_cycles/u -- true

 Performance counter stats for 'true':

           349,613      cpum_cf/cpu_cycles/u

       0.000844143 seconds time elapsed

       0.000079000 seconds user
       0.000800000 seconds sys
 #

Fixes: 6a82e23f45fe ("s390/cpumf: Adjust registration of s390 PMU device drivers")
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
[agordeev@linux.ibm.com corrected commit ID of Fixes commit]
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-29 09:03:26 +02:00
Christian Borntraeger
48543509f4 s390/mm: use non-quiescing sske for KVM switch to keyed guest
commit 3ae11dbcfac906a8c3a480e98660a823130dc16a upstream.

The switch to a keyed guest does not require a classic sske as the other
guest CPUs are not accessing the key before the switch is complete.
By using the NQ SSKE things are faster especially with multiple guests.

Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Suggested-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20220530092706.11637-3-borntraeger@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-25 15:18:40 +02:00
Christian Borntraeger
12eb4e7db2 s390/gmap: voluntarily schedule during key setting
[ Upstream commit 6d5946274df1fff539a7eece458a43be733d1db8 ]

With large and many guest with storage keys it is possible to create
large latencies or stalls during initial key setting:

rcu: INFO: rcu_sched self-detected stall on CPU
rcu:   18-....: (2099 ticks this GP) idle=54e/1/0x4000000000000002 softirq=35598716/35598716 fqs=998
       (t=2100 jiffies g=155867385 q=20879)
Task dump for CPU 18:
CPU 1/KVM       R  running task        0 1030947 256019 0x06000004
Call Trace:
sched_show_task
rcu_dump_cpu_stacks
rcu_sched_clock_irq
update_process_times
tick_sched_handle
tick_sched_timer
__hrtimer_run_queues
hrtimer_interrupt
do_IRQ
ext_int_handler
ptep_zap_key

The mmap lock is held during the page walking but since this is a
semaphore scheduling is still possible. Same for the kvm srcu.
To minimize overhead do this on every segment table entry or large page.

Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20220530092706.11637-2-borntraeger@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-14 18:36:24 +02:00
Alexander Gordeev
66e2bf4b2c s390/mcck: isolate SIE instruction when setting CIF_MCCK_GUEST flag
[ Upstream commit 29ccaa4b35ea874ddd50518e5c2c746b9238a792 ]

Commit d768bd892fc8 ("s390: add options to change branch prediction
behaviour for the kernel") introduced .Lsie_exit label - supposedly
to fence off SIE instruction. However, the corresponding address
range length .Lsie_crit_mcck_length was not updated, which led to
BPON code potentionally marked with CIF_MCCK_GUEST flag.

Both .Lsie_exit and .Lsie_crit_mcck_length were removed with commit
0b0ed657fe00 ("s390: remove critical section cleanup from entry.S"),
but the issue persisted - currently BPOFF and BPENTER macros might
get wrongly considered by the machine check handler as a guest.

Fixes: d768bd892fc8 ("s390: add options to change branch prediction behaviour for the kernel")
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-14 18:36:13 +02:00
Jann Horn
a67b46468a s390/crypto: fix scatterwalk_unmap() callers in AES-GCM
[ Upstream commit bd52cd5e23f134019b23f0c389db0f9a436e4576 ]

The argument of scatterwalk_unmap() is supposed to be the void* that was
returned by the previous scatterwalk_map() call.
The s390 AES-GCM implementation was instead passing the pointer to the
struct scatter_walk.

This doesn't actually break anything because scatterwalk_unmap() only uses
its argument under CONFIG_HIGHMEM and ARCH_HAS_FLUSH_ON_KUNMAP.

Fixes: bf7fa038707c ("s390/crypto: add s390 platform specific aes gcm support.")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Harald Freudenberger <freude@linux.ibm.com>
Link: https://lore.kernel.org/r/20220517143047.3054498-1-jannh@google.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-14 18:36:09 +02:00
Naveen N. Rao
53b858c807 kexec_file: drop weak attribute from arch_kexec_apply_relocations[_add]
commit 3e35142ef99fe6b4fe5d834ad43ee13cca10a2dc upstream.

Since commit d1bcae833b32f1 ("ELF: Don't generate unused section
symbols") [1], binutils (v2.36+) started dropping section symbols that
it thought were unused.  This isn't an issue in general, but with
kexec_file.c, gcc is placing kexec_arch_apply_relocations[_add] into a
separate .text.unlikely section and the section symbol ".text.unlikely"
is being dropped. Due to this, recordmcount is unable to find a non-weak
symbol in .text.unlikely to generate a relocation record against.

Address this by dropping the weak attribute from these functions.
Instead, follow the existing pattern of having architectures #define the
name of the function they want to override in their headers.

[1] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=d1bcae833b32f1

[akpm@linux-foundation.org: arch/s390/include/asm/kexec.h needs linux/module.h]
Link: https://lkml.kernel.org/r/20220519091237.676736-1-naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-09 10:23:27 +02:00
Sven Schnelle
f19e2e1d85 s390/stp: clock_delta should be signed
commit 5ace65ebb5ce9fe1cc8fdbdd97079fb566ef0ea4 upstream.

clock_delta is declared as unsigned long in various places. However,
the clock sync delta can be negative. This would add a huge positive
offset in clock_sync_global where clock_delta is added to clk.eitod
which is a 72 bit integer. Declare it as signed long to fix this.

Cc: stable@vger.kernel.org
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-09 10:23:21 +02:00
Nico Boehr
42b2f5ddc2 s390/perf: obtain sie_block from the right address
commit c9bfb460c3e4da2462e16b0f0b200990b36b1dd2 upstream.

Since commit 1179f170b6f0 ("s390: fix fpu restore in entry.S"), the
sie_block pointer is located at empty1[1], but in sie_block() it was
taken from empty1[0].

This leads to a random pointer being dereferenced, possibly causing
system crash.

This problem can be observed when running a simple guest with an endless
loop and recording the cpu-clock event:

  sudo perf kvm --guestvmlinux=<guestkernel> --guest top -e cpu-clock

With this fix, the correct guest address is shown.

Fixes: 1179f170b6f0 ("s390: fix fpu restore in entry.S")
Cc: stable@vger.kernel.org
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-09 10:23:21 +02:00
Heiko Carstens
69b2965976 s390/preempt: disable __preempt_count_add() optimization for PROFILE_ALL_BRANCHES
[ Upstream commit 63678eecec57fc51b778be3da35a397931287170 ]

gcc 12 does not (always) optimize away code that should only be generated
if parameters are constant and within in a certain range. This depends on
various obscure kernel config options, however in particular
PROFILE_ALL_BRANCHES can trigger this compile error:

In function ‘__atomic_add_const’,
    inlined from ‘__preempt_count_add.part.0’ at ./arch/s390/include/asm/preempt.h:50:3:
./arch/s390/include/asm/atomic_ops.h:80:9: error: impossible constraint in ‘asm’
   80 |         asm volatile(                                                   \
      |         ^~~

Workaround this by simply disabling the optimization for
PROFILE_ALL_BRANCHES, since the kernel will be so slow, that this
optimization won't matter at all.

Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-09 10:22:36 +02:00
Jason A. Donenfeld
e05efd31b9 s390: define get_cycles macro for arch-override
commit 2e3df523256cb9836de8441e9c791a796759bb3c upstream.

S390x defines a get_cycles() function, but it does not do the usual
`#define get_cycles get_cycles` dance, making it impossible for generic
code to see if an arch-specific function was defined. While the
get_cycles() ifdef is not currently used, the following timekeeping
patch in this series will depend on the macro existing (or not existing)
when defining random_get_entropy().

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-30 09:29:13 +02:00
Niklas Schnelle
4e32c4c701 s390/pci: improve zpci_dev reference counting
[ Upstream commit c122383d221dfa2f41cfe5e672540595de986fde ]

Currently zpci_dev uses kref based reference counting but only accounts
for one original reference plus one reference from an added pci_dev to
its underlying zpci_dev. Counting just the original reference worked
until the pci_dev reference was added in commit 2a671f77ee49 ("s390/pci:
fix use after free of zpci_dev") because once a zpci_dev goes away, i.e.
enters the reserved state, it would immediately get released. However
with the pci_dev reference this is no longer the case and the zpci_dev
may still appear in multiple availability events indicating that it was
reserved. This was solved by detecting when the zpci_dev is already on
its way out but still hanging around. This has however shown some light
on how unusual our zpci_dev reference counting is.

Improve upon this by modelling zpci_dev reference counting on pci_dev.
Analogous to pci_get_slot() increment the reference count in
get_zdev_by_fid(). Thus all users of get_zdev_by_fid() must drop the
reference once they are done with the zpci_dev.

Similar to pci_scan_single_device(), zpci_create_device() returns the
device with an initial count of 1 and the device added to the zpci_list
(analogous to the PCI bus' device_list). In turn users of
zpci_create_device() must only drop the reference once the device is
gone from the point of view of the zPCI subsystem, it might still be
referenced by the common PCI subsystem though.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-05-25 09:57:25 +02:00