Commit Graph

7487 Commits

Author SHA1 Message Date
Niklas Schnelle
973c57c5e6 s390: make PCI mio support a machine flag
[ Upstream commit 3322ba0d7bea1e24ae464418626f6a15b69533ab ]

Kernel support for the newer PCI mio instructions can be toggled off
with the pci=nomio command line option which needs to integrate with
common code PCI option parsing. However this option then toggles static
branches which can't be toggled yet in an early_param() call.

Thus commit 9964f396f1 ("s390: fix setting of mio addressing control")
moved toggling the static branches to the PCI init routine.

With this setup however we can't check for mio support outside the PCI
code during early boot, i.e. before switching the static branches, which
we need to be able to export this as an ELF HWCAP.

Improve on this by turning mio availability into a machine flag that
gets initially set based on CONFIG_PCI and the facility bit and gets
toggled off if pci=nomio is found during PCI option parsing allowing
simple access to this machine flag after early init.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
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>
2021-09-18 13:40:22 +02:00
Heiko Carstens
77d62f2bcc s390/jump_label: print real address in a case of a jump label bug
[ Upstream commit 5492886c14744d239e87f1b0b774b5a341e755cc ]

In case of a jump label print the real address of the piece of code
where a mismatch was detected. This is right before the system panics,
so there is nothing revealed.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-18 13:40:22 +02:00
Halil Pasic
1db337b10d KVM: s390: index kvm->arch.idle_mask by vcpu_idx
commit a3e03bc1368c1bc16e19b001fc96dc7430573cc8 upstream.

While in practice vcpu->vcpu_idx ==  vcpu->vcp_id is often true, it may
not always be, and we must not rely on this. Reason is that KVM decides
the vcpu_idx, userspace decides the vcpu_id, thus the two might not
match.

Currently kvm->arch.idle_mask is indexed by vcpu_id, which implies
that code like
for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) {
                vcpu = kvm_get_vcpu(kvm, vcpu_id);
		do_stuff(vcpu);
}
is not legit. Reason is that kvm_get_vcpu expects an vcpu_idx, not an
vcpu_id.  The trouble is, we do actually use kvm->arch.idle_mask like
this. To fix this problem we have two options. Either use
kvm_get_vcpu_by_id(vcpu_id), which would loop to find the right vcpu_id,
or switch to indexing via vcpu_idx. The latter is preferable for obvious
reasons.

Let us make switch from indexing kvm->arch.idle_mask by vcpu_id to
indexing it by vcpu_idx.  To keep gisa_int.kicked_mask indexed by the
same index as idle_mask lets make the same change for it as well.

Fixes: 1ee0bc559d ("KVM: s390: get rid of local_int array")
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Christian Bornträger <borntraeger@de.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 3.15+
Link: https://lore.kernel.org/r/20210827125429.1912577-1-pasic@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-15 09:50:47 +02:00
Peter Oberparleiter
86f9980909 s390/debug: fix debug area life cycle
[ Upstream commit 9372a82892c2caa6bccab9a4081166fa769699f8 ]

Currently allocation and registration of s390dbf debug areas are tied
together. As a result, a debug area cannot be unregistered and
re-registered while any process has an associated debugfs file open.

Fix this by splitting alloc/release from register/unregister.

Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-15 09:50:27 +02:00
Peter Oberparleiter
0980d2b21f s390/debug: keep debug data on resize
[ Upstream commit 1204777867e8486a88dbb4793fe256b31ea05eeb ]

Any previously recorded s390dbf debug data is reset when a debug area
is resized using the 'pages' sysfs attribute. This can make
live-debugging unnecessarily complex.

Fix this by copying existing debug data to the newly allocated debug
area when resizing.

Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-15 09:50:27 +02:00
Niklas Schnelle
0404bf4a66 s390/pci: fix misleading rc in clp_set_pci_fn()
[ Upstream commit f7addcdd527a6dddfebe20c358b87bdb95624612 ]

Currently clp_set_pci_fn() always returns 0 as long as the CLP request
itself succeeds even if the operation itself returns a response code
other than CLP_RC_OK or CLP_RC_SETPCIFN_ALRDY. This is highly misleading
because calling code assumes that a zero rc means that the operation was
successful.

Fix this by returning the response code or cc on failure with the
exception of the special handling for CLP_RC_SETPCIFN_ALRDY. Also let's
not assume that the returned function handle for CLP_RC_SETPCIFN_ALRDY
is 0, we don't need it anyway.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
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>
2021-09-15 09:50:27 +02:00
Alexander Gordeev
8b471e72b5 s390/kasan: fix large PMD pages address alignment check
[ Upstream commit ddd63c85ef67ea9ea7282ad35eafb6568047126e ]

It is currently possible to initialize a large PMD page when
the address is not aligned on page boundary.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@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>
2021-09-15 09:50:27 +02:00
Niklas Schnelle
a69326e134 s390/pci: fix use after free of zpci_dev
[ Upstream commit 2a671f77ee49f3e78997b77fdee139467ff6a598 ]

The struct pci_dev uses reference counting but zPCI assumed erroneously
that the last reference would always be the local reference after
calling pci_stop_and_remove_bus_device(). This is usually the case but
not how reference counting works and thus inherently fragile.

In fact one case where this causes a NULL pointer dereference when on an
SRIOV device the function 0 was hot unplugged before another function of
the same multi-function device. In this case the second function's
pdev->sriov->dev reference keeps the struct pci_dev of function 0 alive
even after the unplug. This bug was previously hidden by the fact that
we were leaking the struct pci_dev which in turn means that it always
outlived the struct zpci_dev. This was fixed in commit 0b13525c20fe
("s390/pci: fix leak of PCI device structure") exposing the broken
behavior.

Fix this by accounting for the long living reference a struct pci_dev
has to its underlying struct zpci_dev via the zbus->function[] array and
only release that in pcibios_release_device() ensuring that the struct
pci_dev is not left with a dangling reference. This is a minimal fix in
the future it would probably better to use fine grained reference
counting for struct zpci_dev.

Fixes: 05bc1be6db ("s390/pci: create zPCI bus")
Cc: stable@vger.kernel.org
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>
2021-08-26 08:35:56 -04:00
Daniel Borkmann
bea9e2fd18 bpf: Introduce BPF nospec instruction for mitigating Spectre v4
[ Upstream commit f5e81d1117501546b7be050c5fbafa6efd2c722c ]

In case of JITs, each of the JIT backends compiles the BPF nospec instruction
/either/ to a machine instruction which emits a speculation barrier /or/ to
/no/ machine instruction in case the underlying architecture is not affected
by Speculative Store Bypass or has different mitigations in place already.

This covers both x86 and (implicitly) arm64: In case of x86, we use 'lfence'
instruction for mitigation. In case of arm64, we rely on the firmware mitigation
as controlled via the ssbd kernel parameter. Whenever the mitigation is enabled,
it works for all of the kernel code with no need to provide any additional
instructions here (hence only comment in arm64 JIT). Other archs can follow
as needed. The BPF nospec instruction is specifically targeting Spectre v4
since i) we don't use a serialization barrier for the Spectre v1 case, and
ii) mitigation instructions for v1 and v4 might be different on some archs.

The BPF nospec is required for a future commit, where the BPF verifier does
annotate intermediate BPF programs with speculation barriers.

Co-developed-by: Piotr Krysiuk <piotras@gmail.com>
Co-developed-by: Benedict Schlueter <benedict.schlueter@rub.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Piotr Krysiuk <piotras@gmail.com>
Signed-off-by: Benedict Schlueter <benedict.schlueter@rub.de>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-04 12:46:44 +02:00
Alexander Egorenkov
37a88b41dc s390/boot: fix use of expolines in the DMA code
commit 463f36c76fa4ec015c640ff63ccf52e7527abee0 upstream.

The DMA code section of the decompressor must be compiled with expolines
if Spectre V2 mitigation has been enabled for the decompressed kernel.
This is required because although the decompressor's image contains
the DMA code section, it is handed over to the decompressed kernel for use.

Because the DMA code is already slow w/o expolines, use expolines always
regardless whether the decompressed kernel is using them or not. This
simplifies the DMA code by dropping the conditional compilation of
expolines.

Fixes: bf72630130 ("s390: use proper expoline sections for .dma code")
Cc: <stable@vger.kernel.org> # 5.2
Signed-off-by: Alexander Egorenkov <egorenar@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>
2021-07-28 14:35:42 +02:00
Vasily Gorbik
d1ab962880 s390/ftrace: fix ftrace_update_ftrace_func implementation
commit f8c2602733c953ed7a16e060640b8e96f9d94b9b upstream.

s390 enforces DYNAMIC_FTRACE if FUNCTION_TRACER is selected.
At the same time implementation of ftrace_caller is not compliant with
HAVE_DYNAMIC_FTRACE since it doesn't provide implementation of
ftrace_update_ftrace_func() and calls ftrace_trace_function() directly.

The subtle difference is that during ftrace code patching ftrace
replaces function tracer via ftrace_update_ftrace_func() and activates
it back afterwards. Unexpected direct calls to ftrace_trace_function()
during ftrace code patching leads to nullptr-dereferences when tracing
is activated for one of functions which are used during code patching.
Those function currently are:
copy_from_kernel_nofault()
copy_from_kernel_nofault_allowed()
preempt_count_sub() [with debug_defconfig]
preempt_count_add() [with debug_defconfig]

Corresponding KASAN report:
 BUG: KASAN: nullptr-dereference in function_trace_call+0x316/0x3b0
 Read of size 4 at addr 0000000000001e08 by task migration/0/15

 CPU: 0 PID: 15 Comm: migration/0 Tainted: G B 5.13.0-41423-g08316af3644d
 Hardware name: IBM 3906 M04 704 (LPAR)
 Stopper: multi_cpu_stop+0x0/0x3e0 <- stop_machine_cpuslocked+0x1e4/0x218
 Call Trace:
  [<0000000001f77caa>] show_stack+0x16a/0x1d0
  [<0000000001f8de42>] dump_stack+0x15a/0x1b0
  [<0000000001f81d56>] print_address_description.constprop.0+0x66/0x2e0
  [<000000000082b0ca>] kasan_report+0x152/0x1c0
  [<00000000004cfd8e>] function_trace_call+0x316/0x3b0
  [<0000000001fb7082>] ftrace_caller+0x7a/0x7e
  [<00000000006bb3e6>] copy_from_kernel_nofault_allowed+0x6/0x10
  [<00000000006bb42e>] copy_from_kernel_nofault+0x3e/0xd0
  [<000000000014605c>] ftrace_make_call+0xb4/0x1f8
  [<000000000047a1b4>] ftrace_replace_code+0x134/0x1d8
  [<000000000047a6e0>] ftrace_modify_all_code+0x120/0x1d0
  [<000000000047a7ec>] __ftrace_modify_code+0x5c/0x78
  [<000000000042395c>] multi_cpu_stop+0x224/0x3e0
  [<0000000000423212>] cpu_stopper_thread+0x33a/0x5a0
  [<0000000000243ff2>] smpboot_thread_fn+0x302/0x708
  [<00000000002329ea>] kthread+0x342/0x408
  [<00000000001066b2>] __ret_from_fork+0x92/0xf0
  [<0000000001fb57fa>] ret_from_fork+0xa/0x30

 The buggy address belongs to the page:
 page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1
 flags: 0x1ffff00000001000(reserved|node=0|zone=0|lastcpupid=0x1ffff)
 raw: 1ffff00000001000 0000040000000048 0000040000000048 0000000000000000
 raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  0000000000001d00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001d80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 >0000000000001e00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
                       ^
  0000000000001e80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
  0000000000001f00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7
 ==================================================================

To fix that introduce ftrace_func callback to be called from
ftrace_caller and update it in ftrace_update_ftrace_func().

Fixes: 4cc9bed034 ("[S390] cleanup ftrace backend functions")
Cc: stable@vger.kernel.org
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>
2021-07-28 14:35:42 +02:00
Colin Ian King
e3a9548ae5 s390/bpf: Perform r1 range checking before accessing jit->seen_reg[r1]
[ Upstream commit 91091656252f5d6d8c476e0c92776ce9fae7b445 ]

Currently array jit->seen_reg[r1] is being accessed before the range
checking of index r1. The range changing on r1 should be performed
first since it will avoid any potential out-of-range accesses on the
array seen_reg[] and also it is more optimal to perform checks on r1
before fetching data from the array. Fix this by swapping the order
of the checks before the array access.

Fixes: 0546231057 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/bpf/20210715125712.24690-1-colin.king@canonical.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28 14:35:37 +02:00
Heiko Carstens
faa3e7da48 s390: introduce proper type handling call_on_stack() macro
[ Upstream commit 41d71fe59cce41237f24f3b7bdc1b414069a34ed ]

The existing CALL_ON_STACK() macro allows for subtle bugs:

- There is no type checking of the function that is being called. That
  is: missing or too many arguments do not cause any compile error or
  warning. The same is true if the return type of the called function
  changes. This can lead to quite random bugs.

- Sign and zero extension of arguments is missing. Given that the s390
  C ABI requires that the caller of a function performs proper sign
  and zero extension this can also lead to subtle bugs.

- If arguments to the CALL_ON_STACK() macros contain functions calls
  register corruption can happen due to register asm constructs being
  used.

Therefore introduce a new call_on_stack() macro which is supposed to
fix all these problems.

Reviewed-by: Sven Schnelle <svens@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>
2021-07-25 14:36:17 +02:00
Ilya Leoshkevich
be10fff3a4 s390/traps: do not test MONITOR CALL without CONFIG_BUG
[ Upstream commit b8e9cc20b808e26329090c19ff80b7f5098e98ff ]

tinyconfig fails to boot, because without CONFIG_BUG report_bug()
always returns BUG_TRAP_TYPE_BUG, which causes mc 0,0 in
test_monitor_call() to panic. Fix by skipping the test without
CONFIG_BUG.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-25 14:36:17 +02:00
Heiko Carstens
a50b56ffc0 s390/mem_detect: fix tprot() program check new psw handling
[ Upstream commit da9057576785aaab52e706e76c0475c85b77ec14 ]

The tprot() inline asm temporarily changes the program check new psw
to redirect a potential program check on the diag instruction.
Restoring of the program check new psw is done in C code behind the
inline asm.

This can be problematic, especially if the function is inlined, since
the compiler can reorder instructions in such a way that a different
instruction, which may result in a program check, might be executed
before the program check new psw has been restored.

To avoid such a scenario move restoring into the inline asm. For
consistency reasons move also saving of the original program check new
psw into the inline asm.

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>
2021-07-20 16:05:44 +02:00
Heiko Carstens
7e1e0235b3 s390/mem_detect: fix diag260() program check new psw handling
[ Upstream commit 86807f348f418a84970eebb8f9912a7eea16b497 ]

The __diag260() inline asm temporarily changes the program check new
psw to redirect a potential program check on the diag instruction.
Restoring of the program check new psw is done in C code behind the
inline asm.

This can be problematic, especially if the function is inlined, since
the compiler can reorder instructions in such a way that a different
instruction, which may result in a program check, might be executed
before the program check new psw has been restored.

To avoid such a scenario move restoring into the inline asm. For
consistency reasons move also saving of the original program check new
psw into the inline asm.

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>
2021-07-20 16:05:44 +02:00
Heiko Carstens
c25be19aa9 s390/ipl_parm: fix program check new psw handling
[ Upstream commit 88c2510cecb7e2b518e3c4fdf3cf0e13ebe9377c ]

The __diag308() inline asm temporarily changes the program check new
psw to redirect a potential program check on the diag instruction.
Restoring of the program check new psw is done in C code behind the
inline asm.

This can be problematic, especially if the function is inlined, since
the compiler can reorder instructions in such a way that a different
instruction, which may result in a program check, might be executed
before the program check new psw has been restored.

To avoid such a scenario move restoring into the inline asm. For
consistency reasons move also saving of the original program check new
psw into the inline asm.

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>
2021-07-20 16:05:44 +02:00
Heiko Carstens
3794633dfd s390/processor: always inline stap() and __load_psw_mask()
[ Upstream commit 9c9a915afd90f7534c16a71d1cd44b58596fddf3 ]

s390 is the only architecture which makes use of the __no_kasan_or_inline
attribute for two functions. Given that both stap() and __load_psw_mask()
are very small functions they can and should be always inlined anyway.

Therefore get rid of __no_kasan_or_inline and always inline these
functions.

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>
2021-07-20 16:05:44 +02:00
Fabrice Fontaine
7b18f26d82 s390: disable SSP when needed
[ Upstream commit 42e8d652438f5ddf04e5dac299cb5e623d113dc0 ]

Though -nostdlib is passed in PURGATORY_LDFLAGS and -ffreestanding in
KBUILD_CFLAGS_DECOMPRESSOR, -fno-stack-protector must also be passed to
avoid linking errors related to undefined references to
'__stack_chk_guard' and '__stack_chk_fail' if toolchain enforces
-fstack-protector.

Fixes
 - https://gitlab.com/kubu93/buildroot/-/jobs/1247043361

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Tested-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Link: https://lore.kernel.org/r/20210510053133.1220167-1-fontaine.fabrice@gmail.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20 16:05:42 +02:00
Valentin Vidic
78cddc9aa6 s390/sclp_vt220: fix console name to match device
[ Upstream commit b7d91d230a119fdcc334d10c9889ce9c5e15118b ]

Console name reported in /proc/consoles:

  ttyS1                -W- (EC p  )    4:65

does not match the char device name:

  crw--w----    1 root     root        4,  65 May 17 12:18 /dev/ttysclp0

so debian-installer inside a QEMU s390x instance gets confused and fails
to start with the following error:

  steal-ctty: No such file or directory

Signed-off-by: Valentin Vidic <vvidic@valentin-vidic.from.hr>
Link: https://lore.kernel.org/r/20210427194010.9330-1-vvidic@valentin-vidic.from.hr
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20 16:05:42 +02:00
Valentin Schneider
ce04375e2d s390: preempt: Fix preempt_count initialization
commit 6a942f5780545ebd11aca8b3ac4b163397962322 upstream.

S390's init_idle_preempt_count(p, cpu) doesn't actually let us initialize the
preempt_count of the requested CPU's idle task: it unconditionally writes
to the current CPU's. This clearly conflicts with idle_threads_init(),
which intends to initialize *all* the idle tasks, including their
preempt_count (or their CPU's, if the arch uses a per-CPU preempt_count).

Unfortunately, it seems the way s390 does things doesn't let us initialize
every possible CPU's preempt_count early on, as the pages where this
resides are only allocated when a CPU is brought up and are freed when it
is brought down.

Let the arch-specific code set a CPU's preempt_count when its lowcore is
allocated, and turn init_idle_preempt_count() into an empty stub.

Fixes: f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20210707163338.1623014-1-valentin.schneider@arm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14 16:56:54 +02:00
Randy Dunlap
045c29902f s390: appldata depends on PROC_SYSCTL
[ Upstream commit 5d3516b3647621d5a1180672ea9e0817fb718ada ]

APPLDATA_BASE should depend on PROC_SYSCTL instead of PROC_FS.
Building with PROC_FS but not PROC_SYSCTL causes a build error,
since appldata_base.c uses data and APIs from fs/proc/proc_sysctl.c.

arch/s390/appldata/appldata_base.o: in function `appldata_generic_handler':
appldata_base.c:(.text+0x192): undefined reference to `sysctl_vals'

Fixes: c185b783b0 ("[S390] Remove config options.")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
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
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Link: https://lore.kernel.org/r/20210528002420.17634-1-rdunlap@infradead.org
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:56:42 +02:00
Niklas Schnelle
485b1c02b5 s390: enable HAVE_IOREMAP_PROT
[ Upstream commit d460bb6c6417588dd8b0907d34f69b237918812a ]

In commit b02002cc4c ("s390/pci: Implement ioremap_wc/prot() with
MIO") we implemented both ioremap_wc() and ioremap_prot() however until
now we had not set HAVE_IOREMAP_PROT in Kconfig, do so now.

This also requires implementing pte_pgprot() as this is used in the
generic_access_phys() code enabled by CONFIG_HAVE_IOREMAP_PROT. As with
ioremap_wc() we need to take the MMIO Write Back bit index into account.

Moreover since the pgprot value returned from pte_pgprot() is to be used
for mappings into kernel address space we must make sure that it uses
appropriate kernel page table protection bits. In particular a pgprot
value originally coming from userspace could have the _PAGE_PROTECT
bit set to enable fault based dirty bit accounting which would then make
the mapping inaccessible when used in kernel address space.

Fixes: b02002cc4c ("s390/pci: Implement ioremap_wc/prot() with MIO")
Reviewed-by: Gerald Schaefer <gerald.schaefer@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>
2021-07-14 16:56:42 +02:00
Heiko Carstens
d65f69deac s390/irq: select HAVE_IRQ_EXIT_ON_IRQ_STACK
[ Upstream commit 9ceed9988a8e6a1656ed2bdaa30501cf0f3dd925 ]

irq_exit() is always called on async stack. Therefore select
HAVE_IRQ_EXIT_ON_IRQ_STACK and get a tiny optimization in
invoke_softirq().

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:56:42 +02:00
Heiko Carstens
b58b54ef49 KVM: s390: get rid of register asm usage
[ Upstream commit 4fa3b91bdee1b08348c82660668ca0ca34e271ad ]

Using register asm statements has been proven to be very error prone,
especially when using code instrumentation where gcc may add function
calls, which clobbers register contents in an unexpected way.

Therefore get rid of register asm statements in kvm code, even though
there is currently nothing wrong with them. This way we know for sure
that this bug class won't be introduced here.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20210621140356.1210771-1-hca@linux.ibm.com
[borntraeger@de.ibm.com: checkpatch strict fix]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:55:56 +02:00
Valentin Schneider
3c51d82d0b sched/core: Initialize the idle task with preemption disabled
[ Upstream commit f1a0a376ca0c4ef1fc3d24e3e502acbb5b795674 ]

As pointed out by commit

  de9b8f5dcb ("sched: Fix crash trying to dequeue/enqueue the idle thread")

init_idle() can and will be invoked more than once on the same idle
task. At boot time, it is invoked for the boot CPU thread by
sched_init(). Then smp_init() creates the threads for all the secondary
CPUs and invokes init_idle() on them.

As the hotplug machinery brings the secondaries to life, it will issue
calls to idle_thread_get(), which itself invokes init_idle() yet again.
In this case it's invoked twice more per secondary: at _cpu_up(), and at
bringup_cpu().

Given smp_init() already initializes the idle tasks for all *possible*
CPUs, no further initialization should be required. Now, removing
init_idle() from idle_thread_get() exposes some interesting expectations
with regards to the idle task's preempt_count: the secondary startup always
issues a preempt_disable(), requiring some reset of the preempt count to 0
between hot-unplug and hotplug, which is currently served by
idle_thread_get() -> idle_init().

Given the idle task is supposed to have preemption disabled once and never
see it re-enabled, it seems that what we actually want is to initialize its
preempt_count to PREEMPT_DISABLED and leave it there. Do that, and remove
init_idle() from idle_thread_get().

Secondary startups were patched via coccinelle:

  @begone@
  @@

  -preempt_disable();
  ...
  cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210512094636.2958515-1-valentin.schneider@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:55:50 +02:00
Janosch Frank
36ae903607 s390: mm: Fix secure storage access exception handling
commit 85b18d7b5e7ffefb2f076186511d39c4990aa005 upstream.

Turns out that the bit 61 in the TEID is not always 1 and if that's
the case the address space ID and the address are
unpredictable. Without an address and its address space ID we can't
export memory and hence we can only send a SIGSEGV to the process or
panic the kernel depending on who caused the exception.

Unfortunately bit 61 is only reliable if we have the "misc" UV feature
bit.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: 084ea4d611 ("s390/mm: add (non)secure page access exceptions handlers")
Cc: stable@vger.kernel.org
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14 16:55:43 +02:00
Heiko Carstens
5fd0c2cf7b s390/stack: fix possible register corruption with stack switch helper
commit 67147e96a332b56c7206238162771d82467f86c0 upstream.

The CALL_ON_STACK macro is used to call a C function from inline
assembly, and therefore must consider the C ABI, which says that only
registers 6-13, and 15 are non-volatile (restored by the called
function).

The inline assembly incorrectly marks all registers used to pass
parameters to the called function as read-only input operands, instead
of operands that are read and written to. This might result in
register corruption depending on usage, compiler, and compile options.

Fix this by marking all operands used to pass parameters as read/write
operands. To keep the code simple even register 6, if used, is marked
as read-write operand.

Fixes: ff340d2472 ("s390: add stack switch helper")
Cc: <stable@kernel.org> # 4.20
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>
2021-06-30 08:47:25 -04:00
Alexander Gordeev
7c003dab43 s390/mcck: fix calculation of SIE critical section size
commit 5bcbe3285fb614c49db6b238253f7daff7e66312 upstream.

The size of SIE critical section is calculated wrongly
as result of a missed subtraction in commit 0b0ed657fe
("s390: remove critical section cleanup from entry.S")

Fixes: 0b0ed657fe ("s390: remove critical section cleanup from entry.S")
Cc: <stable@vger.kernel.org>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.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>
2021-06-23 14:42:51 +02:00
Claudio Imbrenda
b4414fbc0f KVM: s390: extend kvm_s390_shadow_fault to return entry pointer
commit 5ac14bac08ae827b619f21bcceaaac3b8c497e31 upstream.

Extend kvm_s390_shadow_fault to return the pointer to the valid leaf
DAT table entry, or to the invalid entry.

Also return some flags in the lower bits of the address:
PEI_DAT_PROT: indicates that DAT protection applies because of the
              protection bit in the segment (or, if EDAT, region) tables.
PEI_NOT_PTE: indicates that the address of the DAT table entry returned
             does not refer to a PTE, but to a segment or region table.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: stable@vger.kernel.org
Reviewed-by: Janosch Frank <frankja@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Link: https://lore.kernel.org/r/20210302174443.514363-3-imbrenda@linux.ibm.com
[borntraeger@de.ibm.com: fold in a fix from Claudio]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14 09:50:03 +02:00
Claudio Imbrenda
568782de5d KVM: s390: split kvm_s390_real_to_abs
commit c5d1f6b531e68888cbe6718b3f77a60115d58b9c upstream.

A new function _kvm_s390_real_to_abs will apply prefixing to a real address
with a given prefix value.

The old kvm_s390_real_to_abs becomes now a wrapper around the new function.

This is needed to avoid code duplication in vSIE.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210322140559.500716-2-imbrenda@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14 09:50:03 +02:00
Claudio Imbrenda
3804d1a4be KVM: s390: VSIE: fix MVPG handling for prefixing and MSO
commit c3171e94cc1cdcc3229565244112e869f052b8d9 upstream.

Prefixing needs to be applied to the guest real address to translate it
into a guest absolute address.

The value of MSO needs to be added to a guest-absolute address in order to
obtain the host-virtual.

Fixes: bdf7509bbefa ("s390/kvm: VSIE: correctly handle MVPG when in VSIE")
Reported-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210322140559.500716-3-imbrenda@linux.ibm.com
[borntraeger@de.ibm.com simplify mso]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14 09:50:03 +02:00
David Hildenbrand
814cb6de6d s390: fix detection of vector enhancements facility 1 vs. vector packed decimal facility
commit b208108638c4bd3215792415944467c36f5dfd97 upstream.

The PoP documents:
	134: The vector packed decimal facility is installed in the
	     z/Architecture architectural mode. When bit 134 is
	     one, bit 129 is also one.
	135: The vector enhancements facility 1 is installed in
	     the z/Architecture architectural mode. When bit 135
	     is one, bit 129 is also one.

Looks like we confuse the vector enhancements facility 1 ("EXT") with the
Vector packed decimal facility ("BCD"). Let's fix the facility checks.

Detected while working on QEMU/tcg z14 support and only unlocking
the vector enhancements facility 1, but not the vector packed decimal
facility.

Fixes: 2583b848ca ("s390: report new vector facilities")
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20210503121244.25232-1-david@redhat.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14 09:50:03 +02:00
Heiko Carstens
be4ed1ac92 KVM: s390: fix guarded storage control register handling
commit 44bada28219031f9e8e86b84460606efa57b871e upstream.

store_regs_fmt2() has an ordering problem: first the guarded storage
facility is enabled on the local cpu, then preemption disabled, and
then the STGSC (store guarded storage controls) instruction is
executed.

If the process gets scheduled away between enabling the guarded
storage facility and before preemption is disabled, this might lead to
a special operation exception and therefore kernel crash as soon as
the process is scheduled back and the STGSC instruction is executed.

Fixes: 4e0b1ab72b ("KVM: s390: gs support for kvm guests")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Cc: <stable@vger.kernel.org> # 4.12
Link: https://lore.kernel.org/r/20210415080127.1061275-1-hca@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14 09:50:03 +02:00
Claudio Imbrenda
2705bc3f1c KVM: s390: split kvm_s390_logical_to_effective
commit f85f1baaa18932a041fd2b1c2ca6cfd9898c7d2b upstream.

Split kvm_s390_logical_to_effective to a generic function called
_kvm_s390_logical_to_effective. The new function takes a PSW and an address
and returns the address with the appropriate bits masked off. The old
function now calls the new function with the appropriate PSW from the vCPU.

This is needed to avoid code duplication for vSIE.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # for VSIE: correctly handle MVPG when in VSIE
Link: https://lore.kernel.org/r/20210302174443.514363-2-imbrenda@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14 09:50:03 +02:00
Claudio Imbrenda
82de9ad493 KVM: s390: VSIE: correctly handle MVPG when in VSIE
commit bdf7509bbefa20855d5f6bacdc5b62a8489477c9 upstream.

Correctly handle the MVPG instruction when issued by a VSIE guest.

Fixes: a3508fbe9d ("KVM: s390: vsie: initial support for nested virtualization")
Cc: stable@vger.kernel.org # f85f1baaa189: KVM: s390: split kvm_s390_logical_to_effective
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Link: https://lore.kernel.org/r/20210302174443.514363-4-imbrenda@linux.ibm.com
[borntraeger@de.ibm.com: apply fixup from Claudio]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14 09:50:03 +02:00
Harald Freudenberger
a32a2d831d s390/archrandom: add parameter check for s390_arch_random_generate
[ Upstream commit 28096067686c5a5cbd4c35b079749bd805df5010 ]

A review of the code showed, that this function which is exposed
within the whole kernel should do a parameter check for the
amount of bytes requested. If this requested bytes is too high
an unsigned int overflow could happen causing this function to
try to memcpy a really big memory chunk.

This is not a security issue as there are only two invocations
of this function from arch/s390/include/asm/archrandom.h and both
are not exposed to userland.

Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-11 14:47:31 +02:00
Vasily Gorbik
e534a4b139 s390/disassembler: increase ebpf disasm buffer size
commit 6f3353c2d2b3eb4de52e9704cb962712033db181 upstream.

Current ebpf disassembly buffer size of 64 is too small. E.g. this line
takes 65 bytes:
01fffff8005822e: ec8100ed8065\tclgrj\t%r8,%r1,8,001fffff80058408\n\0

Double the buffer size like it is done for the kernel disassembly buffer.

Fixes the following KASAN finding:

UG: KASAN: stack-out-of-bounds in print_fn_code+0x34c/0x380
Write of size 1 at addr 001fff800ad5f970 by task test_progs/853

CPU: 53 PID: 853 Comm: test_progs Not tainted
5.12.0-rc7-23786-g23457d86b1f0-dirty #19
Hardware name: IBM 3906 M04 704 (LPAR)
Call Trace:
 [<0000000cd8e0538a>] show_stack+0x17a/0x1668
 [<0000000cd8e2a5d8>] dump_stack+0x140/0x1b8
 [<0000000cd8e16e74>] print_address_description.constprop.0+0x54/0x260
 [<0000000cd75a8698>] kasan_report+0xc8/0x130
 [<0000000cd6e26da4>] print_fn_code+0x34c/0x380
 [<0000000cd6ea0f4e>] bpf_int_jit_compile+0xe3e/0xe58
 [<0000000cd72c4c88>] bpf_prog_select_runtime+0x5b8/0x9c0
 [<0000000cd72d1bf8>] bpf_prog_load+0xa78/0x19c0
 [<0000000cd72d7ad6>] __do_sys_bpf.part.0+0x18e/0x768
 [<0000000cd6e0f392>] do_syscall+0x12a/0x220
 [<0000000cd8e333f8>] __do_syscall+0x98/0xc8
 [<0000000cd8e54834>] system_call+0x6c/0x94
1 lock held by test_progs/853:
 #0: 0000000cd9bf7460 (report_lock){....}-{2:2}, at:
     kasan_report+0x96/0x130

addr 001fff800ad5f970 is located in stack of task test_progs/853 at
offset 96 in frame:
 print_fn_code+0x0/0x380
this frame has 1 object:
 [32, 96) 'buffer'

Memory state around the buggy address:
 001fff800ad5f800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 001fff800ad5f880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>001fff800ad5f900: 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00 f3 f3
                                                             ^
 001fff800ad5f980: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 001fff800ad5fa00: 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00

Cc: <stable@vger.kernel.org>
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>
2021-05-11 14:47:11 +02:00
Vasily Gorbik
da99331fc6 s390/entry: save the caller of psw_idle
[ Upstream commit a994eddb947ea9ebb7b14d9a1267001699f0a136 ]

Currently psw_idle does not allocate a stack frame and does not
save its r14 and r15 into the save area. Even though this is valid from
call ABI point of view, because psw_idle does not make any calls
explicitly, in reality psw_idle is an entry point for controlled
transition into serving interrupts. So, in practice, psw_idle stack
frame is analyzed during stack unwinding. Depending on build options
that r14 slot in the save area of psw_idle might either contain a value
saved by previous sibling call or complete garbage.

  [task    0000038000003c28] do_ext_irq+0xd6/0x160
  [task    0000038000003c78] ext_int_handler+0xba/0xe8
  [task   *0000038000003dd8] psw_idle_exit+0x0/0x8 <-- pt_regs
 ([task    0000038000003dd8] 0x0)
  [task    0000038000003e10] default_idle_call+0x42/0x148
  [task    0000038000003e30] do_idle+0xce/0x160
  [task    0000038000003e70] cpu_startup_entry+0x36/0x40
  [task    0000038000003ea0] arch_call_rest_init+0x76/0x80

So, to make a stacktrace nicer and actually point for the real caller of
psw_idle in this frequently occurring case, make psw_idle save its r14.

  [task    0000038000003c28] do_ext_irq+0xd6/0x160
  [task    0000038000003c78] ext_int_handler+0xba/0xe8
  [task   *0000038000003dd8] psw_idle_exit+0x0/0x6 <-- pt_regs
 ([task    0000038000003dd8] arch_cpu_idle+0x3c/0xd0)
  [task    0000038000003e10] default_idle_call+0x42/0x148
  [task    0000038000003e30] do_idle+0xce/0x160
  [task    0000038000003e70] cpu_startup_entry+0x36/0x40
  [task    0000038000003ea0] arch_call_rest_init+0x76/0x80

Reviewed-by: Sven Schnelle <svens@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>
2021-04-28 13:40:02 +02:00
Alexander Gordeev
d9dc1b406c s390/cpcmd: fix inline assembly register clobbering
[ Upstream commit 7a2f91441b2c1d81b77c1cd816a4659f4abc9cbe ]

Register variables initialized using arithmetic. That leads to
kasan instrumentaton code corrupting the registers contents.
Follow GCC guidlines and use temporary variables for assigning
init values to register variables.

Fixes: 94c12cc7d1 ("[S390] Inline assembly cleanup.")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://gcc.gnu.org/onlinedocs/gcc-10.2.0/gcc/Local-Register-Variables.html
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-14 08:42:10 +02:00
Heiko Carstens
d88b557b9b s390/vdso: fix tod_steering_delta type
commit b24bacd67ffddd9192c4745500fd6f73dbfe565e upstream.

The s390 specific vdso function __arch_get_hw_counter() is supposed to
consider tod clock steering.

If a tod clock steering event happens and the tod clock is set to a
new value __arch_get_hw_counter() will not return the real tod clock
value but slowly drift it from the old delta until the returned value
finally matches the real tod clock value again.

Unfortunately the type of tod_steering_delta unsigned while it is
supposed to be signed. It depends on if tod_steering_delta is negative
or positive in which direction the vdso code drifts the clock value.

Worst case is now that instead of drifting the clock slowly it will
jump into the opposite direction by a factor of two.

Fix this by simply making tod_steering_delta signed.

Fixes: 4bff8cb545 ("s390: convert to GENERIC_VDSO")
Cc: <stable@vger.kernel.org> # 5.10
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-07 15:00:10 +02:00
Heiko Carstens
b332265430 s390/vdso: copy tod_steering_delta value to vdso_data page
commit 72bbc226ed2ef0a46c165a482861fff00dd6d4e1 upstream.

When converting the vdso assembler code to C it was forgotten to
actually copy the tod_steering_delta value to vdso_data page.

Which in turn means that tod clock steering will not work correctly.

Fix this by simply copying the value whenever it is updated.

Fixes: 4bff8cb545 ("s390: convert to GENERIC_VDSO")
Cc: <stable@vger.kernel.org> # 5.10
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-07 15:00:10 +02:00
Niklas Schnelle
38c74f2f23 s390/pci: fix leak of PCI device structure
commit 0b13525c20febcfecccf6fc1db5969727401317d upstream.

In commit 05bc1be6db ("s390/pci: create zPCI bus") we removed the
pci_dev_put() call matching the earlier pci_get_slot() done as part of
__zpci_event_availability(). This was based on the wrong understanding
that the device_put() done as part of pci_destroy_device() would counter
the pci_get_slot() when it only counters the initial reference. This
same understanding and existing bad example also lead to not doing
a pci_dev_put() in zpci_remove_device().

Since releasing the PCI devices, unlike releasing the PCI slot, does not
print any debug message for testing I added one in pci_release_dev().
This revealed that we are indeed leaking the PCI device on PCI
hotunplug. Further testing also revealed another missing pci_dev_put() in
disable_slot().

Fix this by adding the missing pci_dev_put() in disable_slot() and fix
zpci_remove_device() with the correct pci_dev_put() calls. Also instead
of calling pci_get_slot() in __zpci_event_availability() to determine if
a PCI device is registered and then doing the same again in
zpci_remove_device() do this once in zpci_remove_device() which makes
sure that the pdev in __zpci_event_availability() is only used for the
result of pci_scan_single_device() which does not need a reference count
decremnt as its ownership goes to the PCI bus.

Also move the check if zdev->zbus->bus is set into zpci_remove_device()
since it may be that we're removing a device with devfn != 0 which never
had a PCI bus. So we can still set the pdev->error_state to indicate
that the device is not usable anymore, add a flag to set the error state.

Fixes: 05bc1be6db ("s390/pci: create zPCI bus")
Cc: <stable@vger.kernel.org> # 5.8+: e1bff843cde6 s390/pci: remove superfluous zdev->zbus check
Cc: <stable@vger.kernel.org> # 5.8+: ba764dd703fe s390/pci: refactor zpci_create_device()
Cc: <stable@vger.kernel.org> # 5.8+
Reviewed-by: Matthew Rosato <mjrosato@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>
2021-03-25 09:04:05 +01:00
Niklas Schnelle
075e303474 s390/pci: remove superfluous zdev->zbus check
commit e1bff843cde62a45a287b7f9b4cd5e824e8e49e2 upstream.

Checking zdev->zbus for NULL in __zpci_event_availability() is
superfluous as it can never be NULL at this point. While harmless this
check causes smatch warnings because we later access zdev->zbus with
only having checked zdev != NULL which is sufficient.

The reason zdev->zbus can never be NULL is since with zdev != NULL given
we know the zdev came from get_zdev_by_fid() and thus the zpci_list.
Now on first glance at zpci_create_device() one may assume that there is
a window where the zdev is in the list without a zdev, however this
window can't overlap with __zpci_event_availability() as
zpci_create_device() either runs on the same kthread as part of
availability events, or during the initial CLP List PCI at which point
the __zpci_event_availability() is not yet called as zPCI is not yet
initialized.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-25 09:04:05 +01:00
Niklas Schnelle
bd37d9b9c4 s390/pci: refactor zpci_create_device()
commit ba764dd703feacb5a9c410d191af1b6cfbe96845 upstream.

Currently zpci_create_device() is only called in clp_add_pci_device()
which allocates the memory for the struct zpci_dev being created. There
is little separation of concerns as only both functions together can
create a zpci_dev and the only CLP specific code in
clp_add_pci_device() is a call to clp_query_pci_fn().

Improve this by removing clp_add_pci_device() and refactor
zpci_create_device() such that it alone creates and initializes the
zpci_dev given the FID and Function Handle. For this we need to make
clp_query_pci_fn() non-static. While at it remove the function handle
parameter since we can just take that from the zpci_dev. Also move
adding to the zpci_list to after the zdev has been fully created which
eliminates a window where a partially initialized zdev can be found by
get_zdev_by_fid().

Acked-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-25 09:04:05 +01:00
Gerald Schaefer
015916ca02 s390/vtime: fix increased steal time accounting
commit d54cb7d54877d529bc1e0e1f47a3dd082f73add3 upstream.

Commit 152e9b8676 ("s390/vtime: steal time exponential moving average")
inadvertently changed the input value for account_steal_time() from
"cputime_to_nsecs(steal)" to just "steal", resulting in broken increased
steal time accounting.

Fix this by changing it back to "cputime_to_nsecs(steal)".

Fixes: 152e9b8676 ("s390/vtime: steal time exponential moving average")
Cc: <stable@vger.kernel.org> # 5.1
Reported-by: Sabine Forkel <sabine.forkel@de.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-25 09:04:05 +01:00
Heiko Carstens
e4b98e2260 s390/smp: __smp_rescan_cpus() - move cpumask away from stack
[ Upstream commit 62c8dca9e194326802b43c60763f856d782b225c ]

Avoid a potentially large stack frame and overflow by making
"cpumask_t avail" a static variable. There is no concurrent
access due to the existing locking.

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>
2021-03-17 17:06:25 +01:00
Heiko Carstens
93c5029fb8 s390/vtime: fix inline assembly clobber list
commit b29c5093820d333eef22f58cd04ec0d089059c39 upstream.

The stck/stckf instruction used within the inline assembly within
do_account_vtime() changes the condition code. This is not reflected
with the clobber list, and therefore might result in incorrect code
generation.

It seems unlikely that the compiler could generate incorrect code
considering the surrounding C code, but it must still be fixed.

Cc: <stable@vger.kernel.org>
Reviewed-by: Christian Borntraeger <borntraeger@de.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>
2021-03-04 11:38:42 +01:00
Janosch Frank
9218a6b031 s390: uv: Fix sysfs max number of VCPUs reporting
commit e82080e1f456467cc185fe65ee69fe9f9bd0b576 upstream.

The number reported by the query is N-1 and I think people reading the
sysfs file would expect N instead. For users creating VMs there's no
actual difference because KVM's limit is currently below the UV's
limit.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Fixes: a0f60f8431 ("s390/protvirt: Add sysfs firmware interface for Ultravisor information")
Cc: stable@vger.kernel.org
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-03 23:28:39 +01:00
Randy Dunlap
2179bae04b local64.h: make <asm/local64.h> mandatory
[ Upstream commit 87dbc209ea04645fd2351981f09eff5d23f8e2e9 ]

Make <asm-generic/local64.h> mandatory in include/asm-generic/Kbuild and
remove all arch/*/include/asm/local64.h arch-specific files since they
only #include <asm-generic/local64.h>.

This fixes build errors on arch/c6x/ and arch/nios2/ for
block/blk-iocost.c.

Build-tested on 21 of 25 arch-es.  (tools problems on the others)

Yes, we could even rename <asm-generic/local64.h> to
<linux/local64.h> and change all #includes to use
<linux/local64.h> instead.

Link: https://lkml.kernel.org/r/20201227024446.17018-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <jacquiot.aurelien@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
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>
2021-01-12 20:18:16 +01:00