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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>
[ 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>
[ 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>
[ 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>
[ 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>
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>
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>
[ 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>
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>
[ 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>
[ 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>
[ 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>
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>
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>
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>
[ 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>
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>
[ 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>
[ Upstream commit f09354ffd84eef3c88efa8ba6df05efe50cfd16a ]
There are many different types of translation exceptions but only a
translation-specification exception leads to a kernel panic since it
indicates corrupted page tables, which must never happen.
Improve the panic message so it is a bit more obvious what this is about.
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>
[ Upstream commit 8b202ee218395319aec1ef44f72043e1fbaccdd6 ]
gcc-12 shows a lot of array bound warnings on s390. This is caused
by the S390_lowcore macro which uses a hardcoded address of 0.
Wrapping that with absolute_pointer() works, but gcc no longer knows
that a 12 bit displacement is sufficient to access lowcore. So it
emits instructions like 'lghi %r1,0; l %rx,xxx(%r1)' instead of a
single load/store instruction. As s390 stores variables often
read/written in lowcore, this is considered problematic. Therefore
disable -Warray-bounds on s390 for gcc-12 for the time being, until
there is a better solution.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Link: https://lore.kernel.org/r/yt9dzgkelelc.fsf@linux.ibm.com
Link: https://lore.kernel.org/r/20220422134308.1613610-1-svens@linux.ibm.com
Link: https://lore.kernel.org/r/20220425121742.3222133-1-svens@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c194dad21025dfd043210912653baab823bdff67 upstream.
s390 has a swap_ex_entry_fixup function, however it is not being used
since common code expects a swap_ex_entry_fixup define. If it is not
defined the default implementation will be used. So fix this by adding
a proper define.
However also the implementation of the function must be fixed, since a
NULL value for handler has a special meaning and must not be adjusted.
Luckily all of this doesn't fix a real bug currently: the main extable
is correctly sorted during build time, and for runtime sorting there
is currently no case where the handler field is not NULL.
Fixes: 05a68e892e89 ("s390/kernel: expand exception table logic to allow new handling options")
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@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>
[ Upstream commit 60115fa54ad7b913b7cb5844e6b7ffeb842d55f2 ]
Yongqiang reports a kmemleak panic when module insmod/rmmod with KASAN
enabled(without KASAN_VMALLOC) on x86[1].
When the module area allocates memory, it's kmemleak_object is created
successfully, but the KASAN shadow memory of module allocation is not
ready, so when kmemleak scan the module's pointer, it will panic due to
no shadow memory with KASAN check.
module_alloc
__vmalloc_node_range
kmemleak_vmalloc
kmemleak_scan
update_checksum
kasan_module_alloc
kmemleak_ignore
Note, there is no problem if KASAN_VMALLOC enabled, the modules area
entire shadow memory is preallocated. Thus, the bug only exits on ARCH
which supports dynamic allocation of module area per module load, for
now, only x86/arm64/s390 are involved.
Add a VM_DEFER_KMEMLEAK flags, defer vmalloc'ed object register of
kmemleak in module_alloc() to fix this issue.
[1] https://lore.kernel.org/all/6d41e2b9-4692-5ec4-b1cd-cbe29ae89739@huawei.com/
[wangkefeng.wang@huawei.com: fix build]
Link: https://lkml.kernel.org/r/20211125080307.27225-1-wangkefeng.wang@huawei.com
[akpm@linux-foundation.org: simplify ifdefs, per Andrey]
Link: https://lkml.kernel.org/r/CA+fCnZcnwJHUQq34VuRxpdoY6_XbJCDJ-jopksS5Eia4PijPzw@mail.gmail.com
Link: https://lkml.kernel.org/r/20211124142034.192078-1-wangkefeng.wang@huawei.com
Fixes: 793213a82de4 ("s390/kasan: dynamic shadow mem allocation for modules")
Fixes: 39d114ddc682 ("arm64: add KASAN support")
Fixes: bebf56a1b176 ("kasan: enable instrumentation of global variables")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reported-by: Yongqiang Liu <liuyongqiang13@huawei.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6f390916c4fb359507d9ac4bf1b28a4f8abee5c0 ]
Wrap s390's halt_poll_max_steal with READ_ONCE and snapshot the result of
kvm_arch_no_poll() in kvm_vcpu_block() to avoid a mostly-theoretical,
largely benign bug on s390 where the result of kvm_arch_no_poll() could
change due to userspace modifying halt_poll_max_steal while the vCPU is
blocking. The bug is largely benign as it will either cause KVM to skip
updating halt-polling times (no_poll toggles false=>true) or to update
halt-polling times with a slightly flawed block_ns.
Note, READ_ONCE is unnecessary in the current code, add it in case the
arch hook is ever inlined, and to provide a hint that userspace can
change the param at will.
Fixes: 8b905d28ee17 ("KVM: s390: provide kvm_arch_no_poll function")
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211009021236.4122790-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 2c212e1baedcd782b2535a3f86bc491977677c0e upstream.
Refuse SIDA memops on guests which are not protected.
For normal guests, the secure instruction data address designation,
which determines the location we access, is not under control of KVM.
Fixes: 19e122776886 (KVM: S390: protvirt: Introduce instruction data area bounce buffer)
Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f094a39c6ba168f2df1edfd1731cca377af5f442 upstream.
The machine check validity bit tells about the context. If a KVM guest
was running the bit tells about the guest validity and the host state is
not affected. As a guest can disable the guest validity this might
result in unwanted host errors on machine checks.
Cc: stable@vger.kernel.org
Fixes: c929500d7a5a ("s390/nmi: s390: New low level handling for machine check happening in guest")
Signed-off-by: Christian Borntraeger <borntraeger@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>
commit 1ea1d6a847d2b1d17fefd9196664b95f052a0775 upstream.
machine check validity bits reflect the state of the machine check. If a
guest does not make use of guarded storage, the validity bit might be
off. We can not use the host CR bit to decide if the validity bit must
be on. So ignore "invalid" guarded storage controls for KVM guests in
the host and rely on the machine check being forwarded to the guest. If
no other errors happen from a host perspective everything is fine and no
process must be killed and the host can continue to run.
Cc: stable@vger.kernel.org
Fixes: c929500d7a5a ("s390/nmi: s390: New low level handling for machine check happening in guest")
Reported-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Tested-by: Carsten Otte <cotte@de.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>
commit 663d34c8df98740f1e90241e78e456d00b3c6cad upstream.
Currently if z/VM guest is allowed to retrieve hypervisor performance
data globally for all guests (privilege class B) the query is formed in a
way to include all guests but the group name is left empty. This leads to
that z/VM guests which have access control group set not being included
in the results (even local vm).
Change the query group identifier from empty to "any" to retrieve
information about all guests from any groups (or without a group set).
Cc: stable@vger.kernel.org
Fixes: 31cb4bd31a48 ("[S390] Hypervisor filesystem (s390_hypfs) for z/VM")
Reviewed-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>
commit f3b7e73b2c6619884351a3a0a7468642f852b8a2 upstream.
If the size of the PLT entries generated by apply_rela() exceeds
64KiB, the first ones can no longer reach __jump_r1 with brc. Fix by
using brcl. An alternative solution is to add a __jump_r1 copy after
every 64KiB, however, the space savings are quite small and do not
justify the additional complexity.
Fixes: f19fbd5ed642 ("s390: introduce execute-trampolines for branches")
Cc: stable@vger.kernel.org
Reported-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c2c224932fd0ee6854d6ebfc8d059c2bcad86606 upstream.
There is a race on concurrent 2KB-pgtables release paths when
both upper and lower halves of the containing parent page are
freed, one via page_table_free_rcu() + __tlb_remove_table(),
and the other via page_table_free(). The race might lead to a
corruption as result of remove of list item in page_table_free()
concurrently with __free_page() in __tlb_remove_table().
Let's assume first the lower and next the upper 2KB-pgtables are
freed from a page. Since both halves of the page are allocated
the tracking byte (bits 24-31 of the page _refcount) has value
of 0x03 initially:
CPU0 CPU1
---- ----
page_table_free_rcu() // lower half
{
// _refcount[31..24] == 0x03
...
atomic_xor_bits(&page->_refcount,
0x11U << (0 + 24));
// _refcount[31..24] <= 0x12
...
table = table | (1U << 0);
tlb_remove_table(tlb, table);
}
...
__tlb_remove_table()
{
// _refcount[31..24] == 0x12
mask = _table & 3;
// mask <= 0x01
...
page_table_free() // upper half
{
// _refcount[31..24] == 0x12
...
atomic_xor_bits(
&page->_refcount,
1U << (1 + 24));
// _refcount[31..24] <= 0x10
// mask <= 0x10
...
atomic_xor_bits(&page->_refcount,
mask << (4 + 24));
// _refcount[31..24] <= 0x00
// mask <= 0x00
...
if (mask != 0) // == false
break;
fallthrough;
...
if (mask & 3) // == false
...
else
__free_page(page); list_del(&page->lru);
^^^^^^^^^^^^^^^^^^ RACE! ^^^^^^^^^^^^^^^^^^^^^
} ...
}
The problem is page_table_free() releases the page as result of
lower nibble unset and __tlb_remove_table() observing zero too
early. With this update page_table_free() will use the similar
logic as page_table_free_rcu() + __tlb_remove_table(), and mark
the fragment as pending for removal in the upper nibble until
after the list_del().
In other words, the parent page is considered as unreferenced and
safe to release only when the lower nibble is cleared already and
unsetting a bit in upper nibble results in that nibble turned zero.
Cc: stable@vger.kernel.org
Suggested-by: Vlastimil Babka <vbabka@suse.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-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>
commit 812de04661c4daa7ac385c0dfd62594540538034 upstream.
With KVM_CAP_S390_USER_SIGP, there are only five Signal Processor
orders (CONDITIONAL EMERGENCY SIGNAL, EMERGENCY SIGNAL, EXTERNAL CALL,
SENSE, and SENSE RUNNING STATUS) which are intended for frequent use
and thus are processed in-kernel. The remainder are sent to userspace
with the KVM_CAP_S390_USER_SIGP capability. Of those, three orders
(RESTART, STOP, and STOP AND STORE STATUS) have the potential to
inject work back into the kernel, and thus are asynchronous.
Let's look for those pending IRQs when processing one of the in-kernel
SIGP orders, and return BUSY (CC2) if one is in process. This is in
agreement with the Principles of Operation, which states that only one
order can be "active" on a CPU at a time.
Cc: stable@vger.kernel.org
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20211213210550.856213-2-farman@linux.ibm.com
[borntraeger@linux.ibm.com: add stable tag]
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit abf0e8e4ef25478a4390115e6a953d589d1f9ffd upstream.
Starting with gcc 11.3, the C compiler will generate PLT-relative function
calls even if they are local and do not require it. Later on during linking,
the linker will replace all PLT-relative calls to local functions with
PC-relative ones. Unfortunately, the purgatory code of kexec/kdump is
not being linked as a regular executable or shared library would have been,
and therefore, all PLT-relative addresses remain in the generated purgatory
object code unresolved. This leads to the situation where the purgatory
code is being executed during kdump with all PLT-relative addresses
unresolved. And this results in endless loops within the purgatory code.
Furthermore, the clang C compiler has always behaved like described above
and this commit should fix kdump for kernels built with the latter.
Because the purgatory code is no regular executable or shared library,
contains only calls to local functions and has no PLT, all R_390_PLT32DBL
relocation entries can be resolved just like a R_390_PC32DBL one.
* https://refspecs.linuxfoundation.org/ELF/zSeries/lzsabi0_zSeries/x1633.html#AEN1699
Relocation entries of purgatory code generated with gcc 11.3
------------------------------------------------------------
$ readelf -r linux/arch/s390/purgatory/purgatory.o
Relocation section '.rela.text' at offset 0x370 contains 5 entries:
Offset Info Type Sym. Value Sym. Name + Addend
00000000005c 000c00000013 R_390_PC32DBL 0000000000000000 purgatory_sha_regions + 2
00000000007a 000d00000014 R_390_PLT32DBL 0000000000000000 sha256_update + 2
00000000008c 000e00000014 R_390_PLT32DBL 0000000000000000 sha256_final + 2
000000000092 000800000013 R_390_PC32DBL 0000000000000000 .LC0 + 2
0000000000a0 000f00000014 R_390_PLT32DBL 0000000000000000 memcmp + 2
Relocation entries of purgatory code generated with gcc 11.2
------------------------------------------------------------
$ readelf -r linux/arch/s390/purgatory/purgatory.o
Relocation section '.rela.text' at offset 0x368 contains 5 entries:
Offset Info Type Sym. Value Sym. Name + Addend
00000000005c 000c00000013 R_390_PC32DBL 0000000000000000 purgatory_sha_regions + 2
00000000007a 000d00000013 R_390_PC32DBL 0000000000000000 sha256_update + 2
00000000008c 000e00000013 R_390_PC32DBL 0000000000000000 sha256_final + 2
000000000092 000800000013 R_390_PC32DBL 0000000000000000 .LC0 + 2
0000000000a0 000f00000013 R_390_PC32DBL 0000000000000000 memcmp + 2
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reported-by: Tao Liu <ltao@redhat.com>
Suggested-by: Philipp Rudo <prudo@redhat.com>
Reviewed-by: Philipp Rudo <prudo@redhat.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20211209073817.82196-1-egorenar@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 41967a37b8eedfee15b81406a9f3015be90d3980 ]
arch_kexec_apply_relocations_add currently ignores all errors returned
by arch_kexec_do_relocs. This means that every unknown relocation is
silently skipped causing unpredictable behavior while the relocated code
runs. Fix this by checking for errors and fail kexec_file_load if an
unknown relocation type is encountered.
The problem was found after gcc changed its behavior and used
R_390_PLT32DBL relocations for brasl instruction and relied on ld to
resolve the relocations in the final link in case direct calls are
possible. As the purgatory code is only linked partially (option -r)
ld didn't resolve the relocations leaving them for arch_kexec_do_relocs.
But arch_kexec_do_relocs doesn't know how to handle R_390_PLT32DBL
relocations so they were silently skipped. This ultimately caused an
endless loop in the purgatory as the brasl instructions kept branching
to itself.
Fixes: 71406883fd35 ("s390/kexec_file: Add kexec_file_load system call")
Reported-by: Tao Liu <ltao@redhat.com>
Signed-off-by: Philipp Rudo <prudo@redhat.com>
Link: https://lore.kernel.org/r/20211208130741.5821-3-prudo@redhat.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c9b12b59e2ea4c3c7cedec7efb071b649652f3a9 upstream.
In the current code, when exiting from idle, rcu_irq_enter() is
called twice during irq entry:
irq_entry_enter()-> rcu_irq_enter()
irq_enter() -> rcu_irq_enter()
This may lead to wrong results from rcu_is_cpu_rrupt_from_idle()
because of a wrong dynticks nmi nesting count. Fix this by only
calling irq_enter_rcu().
Cc: <stable@vger.kernel.org> # 5.12+
Reported-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 56e62a737028 ("s390: convert to generic entry")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 53ae7230918154d1f4281d7aa3aae9650436eadf ]
Building with clang & LLVM_IAS=1 leads to an error:
arch/s390/lib/test_unwind.c:179:4: error: invalid register pair
" mvcl %%r1,%%r1\n"
^
The test creates an invalid instruction that would trap at runtime, but the
LLVM inline assembler tries to validate it at compile time too.
Use the raw instruction opcode instead.
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ilie Halip <ilie.halip@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1421
Link: https://lore.kernel.org/r/20211117174822.3632412-1-ilie.halip@gmail.com
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
[hca@linux.ibm.com: use illegal opcode, and update comment]
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 52d04d408185b7aa47628d2339c28ec70074e0ae upstream.
When running without MIO support, with pci=nomio or for devices which
are not MIO-capable the zPCI subsystem generates pseudo-MMIO addresses
to allow access to PCI BARs via MMIO based Linux APIs even though the
platform uses function handles and BAR numbers.
This is done by stashing an index into our global IOMAP array which
contains the function handle in the 16 most significant bits of the
addresses returned by ioremap() always setting the most significant bit.
On the other hand the MIO addresses assigned by the platform for use,
while requiring special instructions, allow PCI access with virtually
mapped physical addresses. Now the problem is that these MIO addresses
and our own pseudo-MMIO addresses may overlap, while functionally this
would not be a problem by itself this overlap is detected by common code
as both address types are added as resources in the iomem_resource tree.
This leads to the overlapping resource claim of either the MIO capable
or non-MIO capable devices with being rejected.
Since PCI is tightly coupled to the use of the iomem_resource tree, see
for example the code for request_mem_region(), we can't reasonably get
rid of the overlap being detected by keeping our pseudo-MMIO addresses
out of the iomem_resource tree.
Instead let's move the range used by our own pseudo-MMIO addresses by
starting at (1UL << 62) and only using addresses below (1UL << 63) thus
avoiding the range currently used for MIO addresses.
Fixes: c7ff0e918a7c ("s390/pci: deal with devices that have no support for MIO instructions")
Cc: stable@vger.kernel.org # 5.3+
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 5dbc4cb4667457b0c53bcd7bff11500b3c362975 ]
There is a difference in how architectures treat "mem=" option. For some
that is an amount of online memory, for s390 and x86 this is the limiting
max address. Some memblock api like memblock_enforce_memory_limit()
take limit argument and explicitly treat it as the size of online memory,
and use __find_max_addr to convert it to an actual max address. Current
s390 usage:
memblock_enforce_memory_limit(memblock_end_of_DRAM());
yields different results depending on presence of memory holes (offline
memory blocks in between online memory). If there are no memory holes
limit == max_addr in memblock_enforce_memory_limit() and it does trim
online memory and reserved memory regions. With memory holes present it
actually does nothing.
Since we already use memblock_remove() explicitly to trim online memory
regions to potential limit (think mem=, kdump, addressing limits, etc.)
drop the usage of memblock_enforce_memory_limit() altogether. Trimming
reserved regions should not be required, since we now use
memblock_set_current_limit() to limit allocations and any explicit memory
reservations above the limit is an actual problem we should not hide.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit fcb116bc43c8c37c052530ead79872f8b2615711 upstream.
Recently to prevent issues with SECCOMP_RET_KILL and similar signals
being changed before they are delivered SA_IMMUTABLE was added.
Unfortunately this broke debuggers[1][2] which reasonably expect
to be able to trap synchronous SIGTRAP and SIGSEGV even when
the target process is not configured to handle those signals.
Add force_exit_sig and use it instead of force_fatal_sig where
historically the code has directly called do_exit. This has the
implementation benefits of going through the signal exit path
(including generating core dumps) without the danger of allowing
userspace to ignore or change these signals.
This avoids userspace regressions as older kernels exited with do_exit
which debuggers also can not intercept.
In the future is should be possible to improve the quality of
implementation of the kernel by changing some of these force_exit_sig
calls to force_fatal_sig. That can be done where it matters on
a case-by-case basis with careful analysis.
Reported-by: Kyle Huey <me@kylehuey.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
[1] https://lkml.kernel.org/r/CAP045AoMY4xf8aC_4QU_-j7obuEPYgTcnQQP3Yxk=2X90jtpjw@mail.gmail.com
[2] https://lkml.kernel.org/r/20211117150258.GB5403@xsang-OptiPlex-9020
Fixes: 00b06da29cf9 ("signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed")
Fixes: a3616a3c0272 ("signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die")
Fixes: 83a1f27ad773 ("signal/powerpc: On swapcontext failure force SIGSEGV")
Fixes: 9bc508cf0791 ("signal/s390: Use force_sigsegv in default_trap_handler")
Fixes: 086ec444f866 ("signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig")
Fixes: c317d306d550 ("signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails")
Fixes: 695dd0d634df ("signal/x86: In emulate_vsyscall force a signal instead of calling do_exit")
Fixes: 1fbd60df8a85 ("signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved.")
Fixes: 941edc5bf174 ("exit/syscall_user_dispatch: Send ordinary signals on failure")
Link: https://lkml.kernel.org/r/871r3dqfv8.fsf_-_@email.froward.int.ebiederm.org
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Kyle Huey <khuey@kylehuey.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Thomas Backlund <tmb@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e21294a7aaae32c5d7154b187113a04db5852e37 upstream.
Now that force_fatal_sig exists it is unnecessary and a bit confusing
to use force_sigsegv in cases where the simpler force_fatal_sig is
wanted. So change every instance we can to make the code clearer.
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Link: https://lkml.kernel.org/r/877de7jrev.fsf@disp2133
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Thomas Backlund <tmb@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9bc508cf0791c8e5a37696de1a046d746fcbd9d8 upstream.
Reading the history it is unclear why default_trap_handler calls
do_exit. It is not even menthioned in the commit where the change
happened. My best guess is that because it is unknown why the
exception happened it was desired to guarantee the process never
returned to userspace.
Using do_exit(SIGSEGV) has the problem that it will only terminate one
thread of a process, leaving the process in an undefined state.
Use force_sigsegv(SIGSEGV) instead which effectively has the same
behavior except that is uses the ordinary signal mechanism and
terminates all threads of a process and is generally well defined.
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Fixes: ca2ab03237ec ("[PATCH] s390: core changes")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Link: https://lkml.kernel.org/r/20211020174406.17889-11-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Thomas Backlund <tmb@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3b90954419d4c05651de9cce6d7632bcf6977678 upstream.
This commit fixes a bug introduced by commit e9e7870f90e3 ("s390/dump:
introduce boot data 'oldmem_data'").
OLDMEM_BASE was mistakenly replaced by oldmem_data.size instead of
oldmem_data.start.
This bug caused the following error during kdump:
kdump.sh[878]: No program header covering vaddr 0x3434f5245found kexec bug?
Fixes: e9e7870f90e3 ("s390/dump: introduce boot data 'oldmem_data'")
Cc: stable@vger.kernel.org # 5.15+
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Marc Hartmayer <mhartmay@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>
commit 00b55eaf45549ce26424224d069a091c7e5d8bac upstream.
When CONFIG_VMAP_STACK is disabled, the user can enable CONFIG_STACK_CHECK,
which adds a stack overflow check to each C function in the kernel. This is
also done for functions in the vdso page. These functions are run in user
context and user stack sizes are usually different to what the kernel uses.
This might trigger the stack check although the stack size is valid.
Therefore filter the -mstack-guard and -mstack-size flags when compiling
vdso C files.
Cc: stable@kernel.org # 5.10+
Fixes: 4bff8cb54502 ("s390: convert to GENERIC_VDSO")
Reported-by: Janosch Frank <frankja@linux.ibm.com>
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>
commit 9a39abb7c9aab50eec4ac4421e9ee7f3de013d24 upstream.
Initial KASAN shadow memory range was picked to preserve original kernel
modules area position. With protected execution support, which might
impose addressing limitation on vmalloc area and hence affect modules
area position, current fixed KASAN shadow memory range is only making
kernel memory layout setup more complex. So move it to the very end of
available virtual space and simplify calculations.
At the same time return to previous kernel address space split. In
particular commit 0c4f2623b957 ("s390: setup kernel memory layout
early") introduced precise identity map size calculation and keeping
vmemmap left most starting from a fresh region table entry. This didn't
take into account additional mapping region requirement for potential
DCSS mapping above available physical memory. So go back to virtual
space split between 1:1 mapping & vmemmap array once vmalloc area size
is subtracted.
Cc: stable@vger.kernel.org
Fixes: 0c4f2623b957 ("s390: setup kernel memory layout early")
Reported-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 420f48f636b98fd685f44a3acc4c0a7c0840910d upstream.
Such reserved memory region, if not cleaned up later causes problems when
memblock_free_all() is called to release free pages to the buddy allocator
and those reserved regions are carried over to reserve_bootmem_region()
which marks the pages as PageReserved.
Instead use memblock_set_current_limit() to make sure memblock allocations
do not go over identity mapping (which could happen when "mem=" option
is used or during kdump).
Cc: stable@vger.kernel.org
Fixes: 73045a08cf55 ("s390: unify identity mapping limits handling")
Reported-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 20c76e242e7025bd355619ba67beb243ba1a1e95 ]
kexec_file_add_ipl_report ignores that ipl_report_finish may fail and
can return an error pointer instead of a valid pointer.
Fix this and simplify by returning NULL in case of an error and let
the only caller handle this case.
Fixes: 99feaa717e55 ("s390/kexec_file: Create ipl report and pass to next kernel")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 9d48c7afedf91a02d03295837ec76b2fb5e7d3fe upstream.
When a CPU is hotplugged while the perf stat -e cycles command is
running, a wrong (very large) value is displayed immediately after the
CPU removal:
Check the values, shouldn't be too high as in
time counts unit events
1.001101919 29261846 cycles
2.002454499 17523405 cycles
3.003659292 24361161 cycles
4.004816983 18446744073638406144 cycles
5.005671647 <not counted> cycles
...
The CPU hotplug off took place after 3 seconds.
The issue is the read of the event count value after 4 seconds when
the CPU is not available and the read of the counter returns an
error. This is treated as a counter value of zero. This results
in a very large value (0 - previous_value).
Fix this by detecting the hotplugged off CPU and report 0 instead
of a very large number.
Cc: stable@vger.kernel.org
Fixes: a029a4eab39e ("s390/cpumf: Allow concurrent access for CPU Measurement Counter Facility")
Reported-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 85f517b29418158d3e6e90c3f0fc01b306d2f1a1 ]
If handle_sske cannot set the storage key, because there is no
page table entry or no present large page entry, it calls
fixup_user_fault.
However, currently, if the call succeeds, handle_sske returns
-EAGAIN, without having set the storage key.
Instead, retry by continue'ing the loop without incrementing the
address.
The same issue in handle_pfmf was fixed by
a11bdb1a6b78 ("KVM: s390: Fix pfmf and conditional skey emulation").
Fixes: bd096f644319 ("KVM: s390: Add skey emulation fault handling")
Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20211022152648.26536-1-scgl@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1e2aa46de526a5adafe580bca4c25856bb06f09e ]
When the system is heavily overcommitted, kvm_s390_pv_init_vm might
generate stall notifications.
Fix this by using uv_call_sched instead of just uv_call. This is ok because
we are not holding spinlocks.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Fixes: 214d9bbcd3a672 ("s390/mm: provide memory management functions for protected KVM guests")
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20210920132502.36111-4-imbrenda@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d4074324b07a94a1fca476d452dfbb3a4e7bf656 ]
If kvm_s390_pv_destroy_cpu is called more than once, we risk calling
free_page on a random page, since the sidad field is aliased with the
gbea, which is not guaranteed to be zero.
This can happen, for example, if userspace calls the KVM_PV_DISABLE
IOCTL, and it fails, and then userspace calls the same IOCTL again.
This scenario is only possible if KVM has some serious bug or if the
hardware is broken.
The solution is to simply return successfully immediately if the vCPU
was already non secure.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Fixes: 19e1227768863a1469797c13ef8fea1af7beac2c ("KVM: S390: protvirt: Introduce instruction data area bounce buffer")
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <20210920132502.36111-3-imbrenda@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 46c22ffd2772201662350bc7b94b9ea9d3ee5ac2 ]
We should not walk/touch page tables outside of VMA boundaries when
holding only the mmap sem in read mode. Evil user space can modify the
VMA layout just before this function runs and e.g., trigger races with
page table removal code since commit dd2283f2605e ("mm: mmap: zap pages
with read mmap_sem in munmap").
find_vma() does not check if the address is >= the VMA start address;
use vma_lookup() instead.
Fixes: 214d9bbcd3a6 ("s390/mm: provide memory management functions for protected KVM guests")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Link: https://lore.kernel.org/r/20210909162248.14969-6-david@redhat.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
