3359 Commits

Author SHA1 Message Date
Thomas Richter b5be6a0bb6 s390/cpum_sf: Handle CPU hotplug remove during sampling
[ Upstream commit a0bd7dacbd ]

CPU hotplug remove handling triggers the following function
call sequence:

   CPUHP_AP_PERF_S390_SF_ONLINE  --> s390_pmu_sf_offline_cpu()
   ...
   CPUHP_AP_PERF_ONLINE          --> perf_event_exit_cpu()

The s390 CPUMF sampling CPU hotplug handler invokes:

 s390_pmu_sf_offline_cpu()
 +-->  cpusf_pmu_setup()
       +--> setup_pmc_cpu()
            +--> deallocate_buffers()

This function de-allocates all sampling data buffers (SDBs) allocated
for that CPU at event initialization. It also clears the
PMU_F_RESERVED bit. The CPU is gone and can not be sampled.

With the event still being active on the removed CPU, the CPU event
hotplug support in kernel performance subsystem triggers the
following function calls on the removed CPU:

  perf_event_exit_cpu()
  +--> perf_event_exit_cpu_context()
       +--> __perf_event_exit_context()
	    +--> __perf_remove_from_context()
	         +--> event_sched_out()
	              +--> cpumsf_pmu_del()
	                   +--> cpumsf_pmu_stop()
                                +--> hw_perf_event_update()

to stop and remove the event. During removal of the event, the
sampling device driver tries to read out the remaining samples from
the sample data buffers (SDBs). But they have already been freed
(and may have been re-assigned). This may lead to a use after free
situation in which case the samples are most likely invalid. In the
best case the memory has not been reassigned and still contains
valid data.

Remedy this situation and check if the CPU is still in reserved
state (bit PMU_F_RESERVED set). In this case the SDBs have not been
released an contain valid data. This is always the case when
the event is removed (and no CPU hotplug off occured).
If the PMU_F_RESERVED bit is not set, the SDB buffers are gone.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14 19:54:37 +01:00
Vasily Gorbik 5bb7a2c3af s390/entry: Mark IRQ entries to fix stack depot warnings
commit 45c9f2b856 upstream.

The stack depot filters out everything outside of the top interrupt
context as an uninteresting or irrelevant part of the stack traces. This
helps with stack trace de-duplication, avoiding an explosion of saved
stack traces that share the same IRQ context code path but originate
from different randomly interrupted points, eventually exhausting the
stack depot.

Filtering uses in_irqentry_text() to identify functions within the
.irqentry.text and .softirqentry.text sections, which then become the
last stack trace entries being saved.

While __do_softirq() is placed into the .softirqentry.text section by
common code, populating .irqentry.text is architecture-specific.

Currently, the .irqentry.text section on s390 is empty, which prevents
stack depot filtering and de-duplication and could result in warnings
like:

Stack depot reached limit capacity
WARNING: CPU: 0 PID: 286113 at lib/stackdepot.c:252 depot_alloc_stack+0x39a/0x3c8

with PREEMPT and KASAN enabled.

Fix this by moving the IO/EXT interrupt handlers from .kprobes.text into
the .irqentry.text section and updating the kprobes blacklist to include
the .irqentry.text section.

This is done only for asynchronous interrupts and explicitly not for
program checks, which are synchronous and where the context beyond the
program check is important to preserve. Despite machine checks being
somewhat in between, they are extremely rare, and preserving context
when possible is also of value.

SVCs and Restart Interrupts are not relevant, one being always at the
boundary to user space and the other being a one-time thing.

IRQ entries filtering is also optionally used in ftrace function graph,
where the same logic applies.

Cc: stable@vger.kernel.org # 5.15+
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>
2024-12-14 19:54:14 +01:00
Masahiro Yamada b1a52470f1 s390/syscalls: Avoid creation of arch/arch/ directory
[ Upstream commit 0708967e2d ]

Building the kernel with ARCH=s390 creates a weird arch/arch/ directory.

  $ find arch/arch
  arch/arch
  arch/arch/s390
  arch/arch/s390/include
  arch/arch/s390/include/generated
  arch/arch/s390/include/generated/asm
  arch/arch/s390/include/generated/uapi
  arch/arch/s390/include/generated/uapi/asm

The root cause is 'targets' in arch/s390/kernel/syscalls/Makefile,
where the relative path is incorrect.

Strictly speaking, 'targets' was not necessary in the first place
because this Makefile uses 'filechk' instead of 'if_changed'.

However, this commit keeps it, as it will be useful when converting
'filechk' to 'if_changed' later.

Fixes: 5c75824d91 ("s390/syscalls: add Makefile to generate system call header files")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20241111134603.2063226-1-masahiroy@kernel.org
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14 19:53:16 +01:00
Thomas Richter beff507e9e s390/cpum_sf: Remove WARN_ON_ONCE statements
[ Upstream commit b495e71015 ]

Remove WARN_ON_ONCE statements. These have not triggered in the
past.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-10-17 15:22:13 +02:00
Heiko Carstens 0ee8425d0c s390/vmlinux.lds.S: Move ro_after_init section behind rodata section
[ Upstream commit 75c10d5377 ]

The .data.rel.ro and .got section were added between the rodata and
ro_after_init data section, which adds an RW mapping in between all RO
mapping of the kernel image:

---[ Kernel Image Start ]---
0x000003ffe0000000-0x000003ffe0e00000        14M PMD RO X
0x000003ffe0e00000-0x000003ffe0ec7000       796K PTE RO X
0x000003ffe0ec7000-0x000003ffe0f00000       228K PTE RO NX
0x000003ffe0f00000-0x000003ffe1300000         4M PMD RO NX
0x000003ffe1300000-0x000003ffe1331000       196K PTE RO NX
0x000003ffe1331000-0x000003ffe13b3000       520K PTE RW NX <---
0x000003ffe13b3000-0x000003ffe13d5000       136K PTE RO NX
0x000003ffe13d5000-0x000003ffe1400000       172K PTE RW NX
0x000003ffe1400000-0x000003ffe1500000         1M PMD RW NX
0x000003ffe1500000-0x000003ffe1700000         2M PTE RW NX
0x000003ffe1700000-0x000003ffe1800000         1M PMD RW NX
0x000003ffe1800000-0x000003ffe187e000       504K PTE RW NX
---[ Kernel Image End ]---

Move the ro_after_init data section again right behind the rodata
section to prevent interleaving RO and RW mappings:

---[ Kernel Image Start ]---
0x000003ffe0000000-0x000003ffe0e00000        14M PMD RO X
0x000003ffe0e00000-0x000003ffe0ec7000       796K PTE RO X
0x000003ffe0ec7000-0x000003ffe0f00000       228K PTE RO NX
0x000003ffe0f00000-0x000003ffe1300000         4M PMD RO NX
0x000003ffe1300000-0x000003ffe1353000       332K PTE RO NX
0x000003ffe1353000-0x000003ffe1400000       692K PTE RW NX
0x000003ffe1400000-0x000003ffe1500000         1M PMD RW NX
0x000003ffe1500000-0x000003ffe1700000         2M PTE RW NX
0x000003ffe1700000-0x000003ffe1800000         1M PMD RW NX
0x000003ffe1800000-0x000003ffe187e000       504K PTE RW NX
---[ Kernel Image End ]---

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: Sasha Levin <sashal@kernel.org>
2024-09-12 11:10:24 +02:00
Heiko Carstens e5d961bff4 s390/smp,mcck: fix early IPI handling
[ Upstream commit 4a1725281f ]

Both the external call as well as the emergency signal submask bits in
control register 0 are set before any interrupt handler is registered.

Change the order and first register the interrupt handler and only then
enable the interrupts by setting the corresponding bits in control
register 0.

This prevents that the second part of the machine check handler for
early machine check handling is not executed: the machine check handler
sends an IPI to the CPU it runs on. If the corresponding interrupts are
enabled, but no interrupt handler is present, the interrupt is ignored.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Acked-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: Sasha Levin <sashal@kernel.org>
2024-08-29 17:30:29 +02:00
David Hildenbrand 1a1eb2f3fc s390/uv: Don't call folio_wait_writeback() without a folio reference
[ Upstream commit 3f29f6537f ]

folio_wait_writeback() requires that no spinlocks are held and that
a folio reference is held, as documented. After we dropped the PTL, the
folio could get freed concurrently. So grab a temporary reference.

Fixes: 214d9bbcd3 ("s390/mm: provide memory management functions for protected KVM guests")
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20240508182955.358628-2-david@redhat.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03 08:49:12 +02:00
Matthew Wilcox (Oracle) cd5df00391 s390/mm: Convert gmap_make_secure to use a folio
[ Upstream commit d35c34bb32 ]

Remove uses of deprecated page APIs, and move the check for large
folios to here to avoid taking the folio lock if the folio is too large.
We could do better here by attempting to split the large folio, but I'll
leave that improvement for someone who can test it.

Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20240322161149.2327518-3-willy@infradead.org
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Stable-dep-of: 3f29f6537f ("s390/uv: Don't call folio_wait_writeback() without a folio reference")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03 08:49:11 +02:00
Matthew Wilcox (Oracle) c6099d3468 s390/mm: Convert make_page_secure to use a folio
[ Upstream commit 259e660d91 ]

These page APIs are deprecated, so convert the incoming page to a folio
and use the folio APIs instead.  The ultravisor API cannot handle large
folios, so return -EINVAL if one has slipped through.

Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20240322161149.2327518-2-willy@infradead.org
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Stable-dep-of: 3f29f6537f ("s390/uv: Don't call folio_wait_writeback() without a folio reference")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-08-03 08:49:11 +02:00
Arnd Bergmann e1b88ac1fe syscalls: fix compat_sys_io_pgetevents_time64 usage
commit d3882564a7 upstream.

Using sys_io_pgetevents() as the entry point for compat mode tasks
works almost correctly, but misses the sign extension for the min_nr
and nr arguments.

This was addressed on parisc by switching to
compat_sys_io_pgetevents_time64() in commit 6431e92fc8 ("parisc:
io_pgetevents_time64() needs compat syscall in 32-bit compat mode"),
as well as by using more sophisticated system call wrappers on x86 and
s390. However, arm64, mips, powerpc, sparc and riscv still have the
same bug.

Change all of them over to use compat_sys_io_pgetevents_time64()
like parisc already does. This was clearly the intention when the
function was originally added, but it got hooked up incorrectly in
the tables.

Cc: stable@vger.kernel.org
Fixes: 48166e6ea4 ("y2038: add 64-bit time_t syscalls to all 32-bit architectures")
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-05 09:31:59 +02:00
Sven Schnelle 0a88433d60 s390/boot: Remove alt_stfle_fac_list from decompressor
[ Upstream commit e7dec0b792 ]

It is nowhere used in the decompressor, therefore remove it.

Fixes: 17e89e1340 ("s390/facilities: move stfl information from lowcore to global data")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12 11:03:44 +02:00
Alexander Egorenkov 34ab36f9f3 s390/ipl: Fix incorrect initialization of nvme dump block
[ Upstream commit 7faacaeaf6 ]

Initialize the correct fields of the nvme dump block.
This bug had not been detected before because first, the fcp and nvme fields
of struct ipl_parameter_block are part of the same union and, therefore,
overlap in memory and second, they are identical in structure and size.

Fixes: d70e38cb1d ("s390: nvme dump support")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12 11:03:43 +02:00
Alexander Egorenkov a88e11b97b s390/ipl: Fix incorrect initialization of len fields in nvme reipl block
[ Upstream commit 9c922b73ac ]

Use correct symbolic constants IPL_BP_NVME_LEN and IPL_BP0_NVME_LEN
to initialize nvme reipl block when 'scp_data' sysfs attribute is
being updated. This bug had not been detected before because
the corresponding fcp and nvme symbolic constants are equal.

Fixes: 23a457b8d5 ("s390: nvme reipl")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12 11:03:43 +02:00
Heiko Carstens a9e6068190 s390/vdso: Use standard stack frame layout
[ Upstream commit 185445c7c1 ]

By default user space is compiled with standard stack frame layout and not
with the packed stack layout. The vdso code however inherited the
-mpacked-stack compiler option from the kernel. Remove this option to make
sure the vdso is compiled with standard stack frame layout.

This makes sure that the stack frame backchain location for vdso generated
stack frames is the same like for calling code (if compiled with default
options). This allows to manually walk stack frames without DWARF
information, like the kernel is doing it e.g. with arch_stack_walk_user().

Fixes: 4bff8cb545 ("s390: convert to GENERIC_VDSO")
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12 11:03:43 +02:00
Jens Remus 8a598bf5ac s390/vdso: Generate unwind information for C modules
[ Upstream commit 10f7052536 ]

GDB fails to unwind vDSO functions with error message "PC not saved",
for instance when stepping through gettimeofday().

Add -fasynchronous-unwind-tables to CFLAGS to generate .eh_frame
DWARF unwind information for the vDSO C modules.

Fixes: 4bff8cb545 ("s390: convert to GENERIC_VDSO")
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12 11:03:43 +02:00
Sumanth Korikkar c7a162b3ae s390/vdso64: filter out munaligned-symbols flag for vdso
[ Upstream commit 8192a1b380 ]

Gcc recently implemented an optimization [1] for loading symbols without
explicit alignment, aligning with the IBM Z ELF ABI. This ABI mandates
symbols to reside on a 2-byte boundary, enabling the use of the larl
instruction. However, kernel linker scripts may still generate unaligned
symbols. To address this, a new -munaligned-symbols option has been
introduced [2] in recent gcc versions.

[1] https://gcc.gnu.org/pipermail/gcc-patches/2023-June/622872.html
[2] https://gcc.gnu.org/pipermail/gcc-patches/2023-August/625986.html

However, when -munaligned-symbols  is used in vdso code, it leads to the
following compilation error:
`.data.rel.ro.local' referenced in section `.text' of
arch/s390/kernel/vdso64/vdso64_generic.o: defined in discarded section
`.data.rel.ro.local' of arch/s390/kernel/vdso64/vdso64_generic.o

vdso linker script discards .data section to make it lightweight.
However, -munaligned-symbols in vdso object files references literal
pool and accesses _vdso_data. Hence, compile vdso code without
-munaligned-symbols.  This means in the future, vdso code should deal
with alignment of newly introduced unaligned linker symbols.

Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Link: https://lore.kernel.org/r/20240219132734.22881-2-sumanthk@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Stable-dep-of: 10f7052536 ("s390/vdso: Generate unwind information for C modules")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12 11:03:43 +02:00
Sumanth Korikkar 926f7fea26 s390/vdso: filter out mno-pic-data-is-text-relative cflag
[ Upstream commit d15e4314ab ]

cmd_vdso_check checks if there are any dynamic relocations in
vdso64.so.dbg. When kernel is compiled with
-mno-pic-data-is-text-relative, R_390_RELATIVE relocs are generated and
this results in kernel build error.

kpatch uses -mno-pic-data-is-text-relative option when building the
kernel to prevent relative addressing between code and data. The flag
avoids relocation error when klp text and data are too far apart

kpatch does not patch vdso code and hence the
mno-pic-data-is-text-relative flag is not essential.

Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Stable-dep-of: 10f7052536 ("s390/vdso: Generate unwind information for C modules")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12 11:03:43 +02:00
Jens Remus 160e19b95b s390/vdso: Add CFI for RA register to asm macro vdso_func
[ Upstream commit b961ec10b9 ]

The return-address (RA) register r14 is specified as volatile in the
s390x ELF ABI [1]. Nevertheless proper CFI directives must be provided
for an unwinder to restore the return address, if the RA register
value is changed from its value at function entry, as it is the case.

[1]: s390x ELF ABI, https://github.com/IBM/s390x-abi/releases

Fixes: 4bff8cb545 ("s390: convert to GENERIC_VDSO")
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-05-17 11:55:59 +02:00
Sumanth Korikkar 447d844a3e s390/entry: align system call table on 8 bytes
commit 378ca2d2ad upstream.

Align system call table on 8 bytes. With sys_call_table entry size
of 8 bytes that eliminates the possibility of a system call pointer
crossing cache line boundary.

Cc: stable@kernel.org
Suggested-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-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>
2024-04-10 16:28:33 +02:00
Mete Durlu abc9b13fd9 s390/vtime: fix average steal time calculation
[ Upstream commit 367c50f784 ]

Current average steal timer calculation produces volatile and inflated
values. The only user of this value is KVM so far and it uses that to
decide whether or not to yield the vCPU which is seeing steal time.
KVM compares average steal timer to a threshold and if the threshold
is past then it does not allow CPU polling and yields it to host, else
it keeps the CPU by polling.
Since KVM's steal time threshold is very low by default (%10) it most
likely is not effected much by the bloated average steal timer values
because the operating region is pretty small. However there might be
new users in the future who might rely on this number. Fix average
steal timer calculation by changing the formula from:

	avg_steal_timer = avg_steal_timer / 2 + steal_timer;

to the following:

	avg_steal_timer = (avg_steal_timer + steal_timer) / 2;

This ensures that avg_steal_timer is actually a naive average of steal
timer values. It now closely follows steal timer values but of course
in a smoother manner.

Fixes: 152e9b8676 ("s390/vtime: steal time exponential moving average")
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:20:59 -04:00
Heiko Carstens 98a2feb8ec s390/cache: prevent rebuild of shared_cpu_list
[ Upstream commit cb0cd4ee11 ]

With commit 36bbc5b4ff ("cacheinfo: Allow early detection and population
of cache attributes") the shared cpu list for each cache level higher than
L1 is rebuilt even if the list already has been set up.

This is caused by the removal of the cpumask_empty() check within
cache_shared_cpu_map_setup().

However architectures can enforce that the shared cpu list is not rebuilt
by simply setting cpu_map_populated of the per cpu cache info structure to
true, which is also the fix for this problem.

Before:
$ cat /sys/devices/system/cpu/cpu1/cache/index2/shared_cpu_list
0-7

After:
$ cat /sys/devices/system/cpu/cpu1/cache/index2/shared_cpu_list
1

Fixes: 36bbc5b4ff ("cacheinfo: Allow early detection and population of cache attributes")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:20:40 -04:00
Nathan Chancellor 9b2ca91f6e s390/vdso: drop '-fPIC' from LDFLAGS
[ Upstream commit 0628c03934 ]

'-fPIC' as an option to the linker does not do what it seems like it
should. With ld.bfd, it is treated as '-f PIC', which does not make
sense based on the meaning of '-f':

  -f SHLIB, --auxiliary SHLIB Auxiliary filter for shared object symbol table

When building with ld.lld (currently under review in a GitHub pull
request), it just errors out because '-f' means nothing and neither does
'-fPIC':

  ld.lld: error: unknown argument '-fPIC'

'-fPIC' was blindly copied from CFLAGS when the vDSO stopped being
linked with '$(CC)', it should not be needed. Remove it to clear up the
build failure with ld.lld.

Fixes: 2b2a25845d ("s390/vdso: Use $(LD) instead of $(CC) to link vDSO")
Link: https://github.com/llvm/llvm-project/pull/75643
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20240130-s390-vdso-drop-fpic-from-ldflags-v1-1-094ad104fc55@kernel.org
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:20:34 -04:00
Thomas Richter 8a2f812b4b s390/pai: fix attr_event_free upper limit for pai device drivers
[ Upstream commit 225d09d6e5 ]

When the device drivers are initialized, a sysfs directory
is created. This contains many attributes which are allocated with
kzalloc(). Should it fail, the memory for the attributes already
created is freed in attr_event_free(). Its second parameter is number
of attribute elements to delete. This parameter is off by one.
When i. e. the 10th attribute fails to get created, attributes
numbered 0 to 9 should be deleted. Currently only attributes
numbered 0 to 8 are deleted.

Fixes: 39d62336f5 ("s390/pai: add support for cryptography counters")
Reported-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:20:34 -04:00
Heiko Carstens 7a4d6481fb s390/ptrace: handle setting of fpc register correctly
[ Upstream commit 8b13601d19 ]

If the content of the floating point control (fpc) register of a traced
process is modified with the ptrace interface the new value is tested for
validity by temporarily loading it into the fpc register.

This may lead to corruption of the fpc register of the tracing process:
if an interrupt happens while the value is temporarily loaded into the
fpc register, and within interrupt context floating point or vector
registers are used, the current fp/vx registers are saved with
save_fpu_regs() assuming they belong to user space and will be loaded into
fp/vx registers when returning to user space.

test_fp_ctl() restores the original user space fpc register value, however
it will be discarded, when returning to user space.

In result the tracer will incorrectly continue to run with the value that
was supposed to be used for the traced process.

Fix this by saving fpu register contents with save_fpu_regs() before using
test_fp_ctl().

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-02-05 20:12:49 +00:00
Thomas Richter 2c14f49916 s390/cpumf: support user space events for counting
[ Upstream commit 91d5364dc6 ]

CPU Measurement counting facility events PROBLEM_STATE_CPU_CYCLES(32)
and PROBLEM_STATE_INSTRUCTIONS(33) are valid events. However the device
driver returns error -EOPNOTSUPP when these event are to be installed.

Fix this and allow installation of events PROBLEM_STATE_CPU_CYCLES,
PROBLEM_STATE_CPU_CYCLES:u, PROBLEM_STATE_INSTRUCTIONS and
PROBLEM_STATE_INSTRUCTIONS:u.
Kernel space counting only is still not supported by s390.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Stable-dep-of: 09cda0a400 ("s390/mm: add missing arch_set_page_dat() call to vmem_crst_alloc()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-10 17:10:30 +01:00
Sven Schnelle f9a3d6f037 s390/ipl: add missing secure/has_secure file to ipl type 'unknown'
commit ea5717cb13 upstream.

OS installers are relying on /sys/firmware/ipl/has_secure to be
present on machines supporting secure boot. This file is present
for all IPL types, but not the unknown type, which prevents a secure
installation when an LPAR is booted in HMC via FTP(s), because
this is an unknown IPL type in linux. While at it, also add the secure
file.

Fixes: c9896acc78 ("s390/ipl: Provide has_secure sysfs attribute")
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>
2023-09-13 09:43:03 +02:00
Heiko Carstens a759972d25 KVM: s390: fix sthyi error handling
[ Upstream commit 0c02cc576e ]

Commit 9fb6c9b3fe ("s390/sthyi: add cache to store hypervisor info")
added cache handling for store hypervisor info. This also changed the
possible return code for sthyi_fill().

Instead of only returning a condition code like the sthyi instruction would
do, it can now also return a negative error value (-ENOMEM). handle_styhi()
was not changed accordingly. In case of an error, the negative error value
would incorrectly injected into the guest PSW.

Add proper error handling to prevent this, and update the comment which
describes the possible return values of sthyi_fill().

Fixes: 9fb6c9b3fe ("s390/sthyi: add cache to store hypervisor info")
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20230727182939.2050744-1-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-11 12:08:11 +02:00
Alexander Gordeev 905b247f6e s390/topology: honour nr_cpu_ids when adding CPUs
[ Upstream commit a33239be2d ]

When SMT thread CPUs are added to CPU masks the nr_cpu_ids
limit is not checked and could be exceeded. This leads to
a warning for example if CONFIG_DEBUG_PER_CPU_MAPS is set
and the command line parameter nr_cpus is set to 1.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-06-09 10:34:13 +02:00
Ze Gao 7099e14f60 rethook, fprobe: do not trace rethook related functions
commit 571a2a50a8 upstream.

These functions are already marked as NOKPROBE to prevent recursion and
we have the same reason to blacklist them if rethook is used with fprobe,
since they are beyond the recursion-free region ftrace can guard.

Link: https://lore.kernel.org/all/20230517034510.15639-5-zegao@tencent.com/

Fixes: f3a112c0c4 ("x86,rethook,kprobes: Replace kretprobe with rethook on x86")
Signed-off-by: Ze Gao <zegao@tencent.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-05-24 17:32:53 +01:00
Claudio Imbrenda c6fafaa6f2 KVM: s390: fix race in gmap_make_secure()
[ Upstream commit c148dc8e2f ]

Fix a potential race in gmap_make_secure() and remove the last user of
follow_page() without FOLL_GET.

The old code is locking something it doesn't have a reference to, and
as explained by Jason and David in this discussion:
https://lore.kernel.org/linux-mm/Y9J4P%2FRNvY1Ztn0Q@nvidia.com/
it can lead to all kind of bad things, including the page getting
unmapped (MADV_DONTNEED), freed, reallocated as a larger folio and the
unlock_page() would target the wrong bit.
There is also another race with the FOLL_WRITE, which could race
between the follow_page() and the get_locked_pte().

The main point is to remove the last use of follow_page() without
FOLL_GET or FOLL_PIN, removing the races can be considered a nice
bonus.

Link: https://lore.kernel.org/linux-mm/Y9J4P%2FRNvY1Ztn0Q@nvidia.com/
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Fixes: 214d9bbcd3 ("s390/mm: provide memory management functions for protected KVM guests")
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-Id: <20230428092753.27913-2-imbrenda@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-05-17 11:53:38 +02:00
Heiko Carstens 3059a67e02 s390/ptrace: fix PTRACE_GET_LAST_BREAK error handling
[ Upstream commit f9bbf25e7b ]

Return -EFAULT if put_user() for the PTRACE_GET_LAST_BREAK
request fails, instead of silently ignoring it.

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>
2023-04-26 14:28:36 +02:00
Vasily Gorbik f9a38f5ecf s390/kprobes: fix current_kprobe never cleared after kprobes reenter
commit cd57953936 upstream.

Recent test_kprobe_missed kprobes kunit test uncovers the following
problem. Once kprobe is triggered from another kprobe (kprobe reenter),
all future kprobes on this cpu are considered as kprobe reenter, thus
pre_handler and post_handler are not being called and kprobes are counted
as "missed".

Commit b9599798f9 ("[S390] kprobes: activation and deactivation")
introduced a simpler scheme for kprobes (de)activation and status
tracking by using push_kprobe/pop_kprobe, which supposed to work for
both initial kprobe entry as well as kprobe reentry and helps to avoid
handling those two cases differently. The problem is that a sequence of
calls in case of kprobes reenter:
push_kprobe() <- NULL (current_kprobe)
push_kprobe() <- kprobe1 (current_kprobe)
pop_kprobe() -> kprobe1 (current_kprobe)
pop_kprobe() -> kprobe1 (current_kprobe)
leaves "kprobe1" as "current_kprobe" on this cpu, instead of setting it
to NULL. In fact push_kprobe/pop_kprobe can only store a single state
(there is just one prev_kprobe in kprobe_ctlblk). Which is a hack but
sufficient, there is no need to have another prev_kprobe just to store
NULL. To make a simple and backportable fix simply reset "prev_kprobe"
when kprobe is poped from this "stack". No need to worry about
"kprobe_status" in this case, because its value is only checked when
current_kprobe != NULL.

Cc: stable@vger.kernel.org
Fixes: b9599798f9 ("[S390] kprobes: activation and deactivation")
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>
2023-03-10 09:34:04 +01:00
Vasily Gorbik 70afa77327 s390/kprobes: fix irq mask clobbering on kprobe reenter from post_handler
commit 42e19e6f04 upstream.

Recent test_kprobe_missed kprobes kunit test uncovers the following error
(reported when CONFIG_DEBUG_ATOMIC_SLEEP is enabled):

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 662, name: kunit_try_catch
preempt_count: 0, expected: 0
RCU nest depth: 0, expected: 0
no locks held by kunit_try_catch/662.
irq event stamp: 280
hardirqs last  enabled at (279): [<00000003e60a3d42>] __do_pgm_check+0x17a/0x1c0
hardirqs last disabled at (280): [<00000003e3bd774a>] kprobe_exceptions_notify+0x27a/0x318
softirqs last  enabled at (0): [<00000003e3c5c890>] copy_process+0x14a8/0x4c80
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 46 PID: 662 Comm: kunit_try_catch Tainted: G                 N 6.2.0-173644-g44c18d77f0c0 #2
Hardware name: IBM 3931 A01 704 (LPAR)
Call Trace:
 [<00000003e60a3a00>] dump_stack_lvl+0x120/0x198
 [<00000003e3d02e82>] __might_resched+0x60a/0x668
 [<00000003e60b9908>] __mutex_lock+0xc0/0x14e0
 [<00000003e60bad5a>] mutex_lock_nested+0x32/0x40
 [<00000003e3f7b460>] unregister_kprobe+0x30/0xd8
 [<00000003e51b2602>] test_kprobe_missed+0xf2/0x268
 [<00000003e51b5406>] kunit_try_run_case+0x10e/0x290
 [<00000003e51b7dfa>] kunit_generic_run_threadfn_adapter+0x62/0xb8
 [<00000003e3ce30f8>] kthread+0x2d0/0x398
 [<00000003e3b96afa>] __ret_from_fork+0x8a/0xe8
 [<00000003e60ccada>] ret_from_fork+0xa/0x40

The reason for this error report is that kprobes handling code failed
to restore irqs.

The problem is that when kprobe is triggered from another kprobe
post_handler current sequence of enable_singlestep / disable_singlestep
is the following:
enable_singlestep  <- original kprobe (saves kprobe_saved_imask)
enable_singlestep  <- kprobe triggered from post_handler (clobbers kprobe_saved_imask)
disable_singlestep <- kprobe triggered from post_handler (restores kprobe_saved_imask)
disable_singlestep <- original kprobe (restores wrong clobbered kprobe_saved_imask)

There is just one kprobe_ctlblk per cpu and both calls saves and
loads irq mask to kprobe_saved_imask. To fix the problem simply move
resume_execution (which calls disable_singlestep) before calling
post_handler. This also fixes the problem that post_handler is called
with pt_regs which were not yet adjusted after single-stepping.

Cc: stable@vger.kernel.org
Fixes: 4ba069b802 ("[S390] add kprobes support.")
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>
2023-03-10 09:34:04 +01:00
Ilya Leoshkevich a829c5f7c3 s390: discard .interp section
commit e9c9cb90e7 upstream.

When debugging vmlinux with QEMU + GDB, the following GDB error may
occur:

    (gdb) c
    Continuing.
    Warning:
    Cannot insert breakpoint -1.
    Cannot access memory at address 0xffffffffffff95c0

    Command aborted.
    (gdb)

The reason is that, when .interp section is present, GDB tries to
locate the file specified in it in memory and put a number of
breakpoints there (see enable_break() function in gdb/solib-svr4.c).
Sometimes GDB finds a bogus location that matches its heuristics,
fails to set a breakpoint and stops. This makes further debugging
impossible.

The .interp section contains misleading information anyway (vmlinux
does not need ld.so), so fix by discarding it.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:04 +01:00
Heiko Carstens 611c390217 s390/idle: mark arch_cpu_idle() noinstr
[ Upstream commit a9cbc1b471 ]

linux-next commit ("cpuidle: tracing: Warn about !rcu_is_watching()")
adds a new warning which hits on s390's arch_cpu_idle() function:

RCU not on for: arch_cpu_idle+0x0/0x28
WARNING: CPU: 2 PID: 0 at include/linux/trace_recursion.h:162 arch_ftrace_ops_list_func+0x24c/0x258
Modules linked in:
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 6.2.0-rc6-next-20230202 #4
Hardware name: IBM 8561 T01 703 (z/VM 7.3.0)
Krnl PSW : 0404d00180000000 00000000002b55c0 (arch_ftrace_ops_list_func+0x250/0x258)
           R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 RI:0 EA:3
Krnl GPRS: c0000000ffffbfff 0000000080000002 0000000000000026 0000000000000000
           0000037ffffe3a28 0000037ffffe3a20 0000000000000000 0000000000000000
           0000000000000000 0000000000f4acf6 00000000001044f0 0000037ffffe3cb0
           0000000000000000 0000000000000000 00000000002b55bc 0000037ffffe3bb8
Krnl Code: 00000000002b55b0: c02000840051        larl    %r2,0000000001335652
           00000000002b55b6: c0e5fff512d1        brasl   %r14,0000000000157b58
          #00000000002b55bc: af000000            mc      0,0
          >00000000002b55c0: a7f4ffe7            brc     15,00000000002b558e
           00000000002b55c4: 0707                bcr     0,%r7
           00000000002b55c6: 0707                bcr     0,%r7
           00000000002b55c8: eb6ff0480024        stmg    %r6,%r15,72(%r15)
           00000000002b55ce: b90400ef            lgr     %r14,%r15
Call Trace:
 [<00000000002b55c0>] arch_ftrace_ops_list_func+0x250/0x258
([<00000000002b55bc>] arch_ftrace_ops_list_func+0x24c/0x258)
 [<0000000000f5f0fc>] ftrace_common+0x1c/0x20
 [<00000000001044f6>] arch_cpu_idle+0x6/0x28
 [<0000000000f4acf6>] default_idle_call+0x76/0x128
 [<00000000001cc374>] do_idle+0xf4/0x1b0
 [<00000000001cc6ce>] cpu_startup_entry+0x36/0x40
 [<0000000000119d00>] smp_start_secondary+0x140/0x150
 [<0000000000f5d2ae>] restart_int_handler+0x6e/0x90

Mark arch_cpu_idle() noinstr like all other architectures with
CONFIG_ARCH_WANTS_NO_INSTR (should) have it to fix this.

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>
2023-03-10 09:33:52 +01:00
Nathan Chancellor 8570655c0f s390/vdso: Drop '-shared' from KBUILD_CFLAGS_64
[ Upstream commit fd8589dce8 ]

When clang's -Qunused-arguments is dropped from KBUILD_CPPFLAGS, it
points out that there is a linking phase flag added to CFLAGS, which
will only be used for compiling

  clang-16: error: argument unused during compilation: '-shared' [-Werror,-Wunused-command-line-argument]

'-shared' is already present in ldflags-y so it can just be dropped.

Fixes: 2b2a25845d ("s390/vdso: Use $(LD) instead of $(CC) to link vDSO")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-10 09:33:41 +01:00
Alexander Gordeev ec75af7e81 s390/early: fix sclp_early_sccb variable lifetime
[ Upstream commit 639886b71d ]

Commit ada1da31ce ("s390/sclp: sort out physical vs
virtual pointers usage") fixed the notion of virtual
address for sclp_early_sccb pointer. However, it did
not take into account that kasan_early_init() can also
output messages and sclp_early_sccb should be adjusted
by the time kasan_early_init() is called.

Currently it is not a problem, since virtual and physical
addresses on s390 are the same. Nevertheless, should they
ever differ, this would cause an invalid pointer access.

Fixes: ada1da31ce ("s390/sclp: sort out physical vs virtual pointers usage")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-10 09:32:53 +01:00
Masahiro Yamada af3fae1cb2 s390: define RUNTIME_DISCARD_EXIT to fix link error with GNU ld < 2.36
commit a494398bde upstream.

Nathan Chancellor reports that the s390 vmlinux fails to link with
GNU ld < 2.36 since commit 99cb0d917f ("arch: fix broken BuildID
for arm64 and riscv").

It happens for defconfig, or more specifically for CONFIG_EXPOLINE=y.

  $ s390x-linux-gnu-ld --version | head -n1
  GNU ld (GNU Binutils for Debian) 2.35.2
  $ make -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- allnoconfig
  $ ./scripts/config -e CONFIG_EXPOLINE
  $ make -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- olddefconfig
  $ make -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu-
  `.exit.text' referenced in section `.s390_return_reg' of drivers/base/dd.o: defined in discarded section `.exit.text' of drivers/base/dd.o
  make[1]: *** [scripts/Makefile.vmlinux:34: vmlinux] Error 1
  make: *** [Makefile:1252: vmlinux] Error 2

arch/s390/kernel/vmlinux.lds.S wants to keep EXIT_TEXT:

        .exit.text : {
                EXIT_TEXT
        }

But, at the same time, EXIT_TEXT is thrown away by DISCARD because
s390 does not define RUNTIME_DISCARD_EXIT.

I still do not understand why the latter wins after 99cb0d917f,
but defining RUNTIME_DISCARD_EXIT seems correct because the comment
line in arch/s390/kernel/vmlinux.lds.S says:

        /*
         * .exit.text is discarded at runtime, not link time,
         * to deal with references from __bug_table
         */

Nathan also found that binutils commit 21401fc7bf67 ("Duplicate output
sections in scripts") cured this issue, so we cannot reproduce it with
binutils 2.36+, but it is better to not rely on it.

Fixes: 99cb0d917f ("arch: fix broken BuildID for arm64 and riscv")
Link: https://lore.kernel.org/all/Y7Jal56f6UBh1abE@dev-arch.thelio-3990X/
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20230105031306.1455409-1-masahiroy@kernel.org
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Tom Saeger <tom.saeger@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-25 11:25:42 +01:00
Al Viro 5a19095103 use less confusing names for iov_iter direction initializers
[ Upstream commit de4eda9de2 ]

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Stable-dep-of: 6dd88fd59d ("vhost-scsi: unbreak any layout for response")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-09 11:28:04 +01:00
Al Viro 0332bdec06 copy_oldmem_kernel() - WRITE is "data source", not destination
[ Upstream commit 0e1e4a2238 ]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Stable-dep-of: 6dd88fd59d ("vhost-scsi: unbreak any layout for response")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-09 11:28:03 +01:00
Heiko Carstens 1fc24f9da2 s390: workaround invalid gcc-11 out of bounds read warning
[ Upstream commit 41e1992665 ]

GCC 11.1.0 and 11.2.0 generate a wrong warning when compiling the
kernel e.g. with allmodconfig:

arch/s390/kernel/setup.c: In function ‘setup_lowcore_dat_on’:
./include/linux/fortify-string.h:57:33: error: ‘__builtin_memcpy’ reading 128 bytes from a region of size 0 [-Werror=stringop-overread]
...
arch/s390/kernel/setup.c:526:9: note: in expansion of macro ‘memcpy’
  526 |         memcpy(abs_lc->cregs_save_area, S390_lowcore.cregs_save_area,
      |         ^~~~~~

This could be addressed by using absolute_pointer() with the
S390_lowcore macro, but this is not a good idea since this generates
worse code for performance critical paths.

Therefore simply use a for loop to copy the array in question and get
rid of the warning.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-06 08:06:33 +01:00
Alexander Gordeev 25714807b1 s390: expicitly align _edata and _end symbols on page boundary
[ Upstream commit 45d619bdaf ]

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

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

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

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:30 +01:00
Heiko Carstens 45a584f139 s390/cpum_sf: add READ_ONCE() semantics to compare and swap loops
commit 82d3edb50a upstream.

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

For example:

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

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

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

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

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

Reported-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/linux-s390/Y71QJBhNTIatvxUT@osiris/T/#ma14e2a5f7aa8ed4b94b6f9576799b3ad9c60f333
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:58:12 +01:00
Alexander Egorenkov ab4b5a2154 s390/kexec: fix ipl report address for kdump
commit c2337a40e0 upstream.

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

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

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

Cc: <stable@vger.kernel.org>
Fixes: 99feaa717e ("s390/kexec_file: Create ipl report and pass to next kernel")
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-18 11:58:11 +01:00
Heiko Carstens f44e07a8af s390/crashdump: fix TOD programmable field size
The size of the TOD programmable field was incorrectly increased from
four to eight bytes with commit 1a2c5840ac ("s390/dump: cleanup CPU
save area handling").
This leads to an elf notes section NT_S390_TODPREG which has a size of
eight instead of four bytes in case of kdump, however even worse is
that the contents is incorrect: it is supposed to contain only the
contents of the TOD programmable field, but in fact contains a mix of
the TOD programmable field (32 bit upper bits) and parts of the CPU
timer register (lower 32 bits).

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

This also gets rid of this compile time warning:

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

Fixes: 1a2c5840ac ("s390/dump: cleanup CPU save area handling")
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2022-11-24 13:45:05 +01:00
Thomas Richter 8b1e6a3fb3 s390/pai: fix raw data collection for PMU pai_ext
Commit 838d9bb62d ("perf: Use sample_flags for raw_data")
changed the way the raw data of an event is collected.
Adjust the PMU pai_ext to the new scheme.

Fixes: 838d9bb62d ("perf: Use sample_flags for raw_data")
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2022-10-26 14:47:31 +02:00
Jason A. Donenfeld f743f16c54 treewide: use get_random_{u8,u16}() when possible, part 2
Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value,
simply use the get_random_{u8,u16}() functions, which are faster than
wasting the additional bytes from a 32-bit value. This was done by hand,
identifying all of the places where one of the random integer functions
was used in a non-32-bit context.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-11 17:42:58 -06:00
Jason A. Donenfeld 81895a65ec treewide: use prandom_u32_max() when possible, part 1
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

-       RAND = get_random_u32();
        ... when != RAND
-       RAND %= (E);
+       RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

        ((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
        value = int(literal, 16)
elif literal[0] in '123456789':
        value = int(literal, 10)
if value is None:
        print("I don't know how to handle %s" % (literal))
        cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
        print("Skipping 0x%x for cleanup elsewhere" % (value))
        cocci.include_match(False)
elif value & (value + 1) != 0:
        print("Skipping 0x%x because it's not a power of two minus one" % (value))
        cocci.include_match(False)
elif literal.startswith('0x'):
        coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
        coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

-       (FUNC()@p & (LITERAL))
+       prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

 {
-       T VAR;
-       VAR = (E);
-       return VAR;
+       return E;
 }

@drop_var@
type T;
identifier VAR;
@@

 {
-       T VAR;
        ... when != VAR
 }

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-11 17:42:55 -06:00
Linus Torvalds 27bc50fc90 Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:

 - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
   linux-next for a couple of months without, to my knowledge, any
   negative reports (or any positive ones, come to that).

 - Also the Maple Tree from Liam Howlett. An overlapping range-based
   tree for vmas. It it apparently slightly more efficient in its own
   right, but is mainly targeted at enabling work to reduce mmap_lock
   contention.

   Liam has identified a number of other tree users in the kernel which
   could be beneficially onverted to mapletrees.

   Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
   at [1]. This has yet to be addressed due to Liam's unfortunately
   timed vacation. He is now back and we'll get this fixed up.

 - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
   clang-generated instrumentation to detect used-unintialized bugs down
   to the single bit level.

   KMSAN keeps finding bugs. New ones, as well as the legacy ones.

 - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
   memory into THPs.

 - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
   support file/shmem-backed pages.

 - userfaultfd updates from Axel Rasmussen

 - zsmalloc cleanups from Alexey Romanov

 - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
   memory-failure

 - Huang Ying adds enhancements to NUMA balancing memory tiering mode's
   page promotion, with a new way of detecting hot pages.

 - memcg updates from Shakeel Butt: charging optimizations and reduced
   memory consumption.

 - memcg cleanups from Kairui Song.

 - memcg fixes and cleanups from Johannes Weiner.

 - Vishal Moola provides more folio conversions

 - Zhang Yi removed ll_rw_block() :(

 - migration enhancements from Peter Xu

 - migration error-path bugfixes from Huang Ying

 - Aneesh Kumar added ability for a device driver to alter the memory
   tiering promotion paths. For optimizations by PMEM drivers, DRM
   drivers, etc.

 - vma merging improvements from Jakub Matěn.

 - NUMA hinting cleanups from David Hildenbrand.

 - xu xin added aditional userspace visibility into KSM merging
   activity.

 - THP & KSM code consolidation from Qi Zheng.

 - more folio work from Matthew Wilcox.

 - KASAN updates from Andrey Konovalov.

 - DAMON cleanups from Kaixu Xia.

 - DAMON work from SeongJae Park: fixes, cleanups.

 - hugetlb sysfs cleanups from Muchun Song.

 - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.

Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]

* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
  hugetlb: allocate vma lock for all sharable vmas
  hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
  hugetlb: fix vma lock handling during split vma and range unmapping
  mglru: mm/vmscan.c: fix imprecise comments
  mm/mglru: don't sync disk for each aging cycle
  mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
  mm: memcontrol: use do_memsw_account() in a few more places
  mm: memcontrol: deprecate swapaccounting=0 mode
  mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
  mm/secretmem: remove reduntant return value
  mm/hugetlb: add available_huge_pages() func
  mm: remove unused inline functions from include/linux/mm_inline.h
  selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
  selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
  selftests/vm: add thp collapse shmem testing
  selftests/vm: add thp collapse file and tmpfs testing
  selftests/vm: modularize thp collapse memory operations
  selftests/vm: dedup THP helpers
  mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
  mm/madvise: add file and shmem support to MADV_COLLAPSE
  ...
2022-10-10 17:53:04 -07:00
Linus Torvalds 8afc66e8d4 Merge tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:

 - Remove potentially incomplete targets when Kbuid is interrupted by
   SIGINT etc in case GNU Make may miss to do that when stderr is piped
   to another program.

 - Rewrite the single target build so it works more correctly.

 - Fix rpm-pkg builds with V=1.

 - List top-level subdirectories in ./Kbuild.

 - Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in
   kallsyms.

 - Avoid two different modules in lib/zstd/ having shared code, which
   potentially causes building the common code as build-in and modular
   back-and-forth.

 - Unify two modpost invocations to optimize the build process.

 - Remove head-y syntax in favor of linker scripts for placing
   particular sections in the head of vmlinux.

 - Bump the minimal GNU Make version to 3.82.

 - Clean up misc Makefiles and scripts.

* tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits)
  docs: bump minimal GNU Make version to 3.82
  ia64: simplify esi object addition in Makefile
  Revert "kbuild: Check if linker supports the -X option"
  kbuild: rebuild .vmlinux.export.o when its prerequisite is updated
  kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o
  zstd: Fixing mixed module-builtin objects
  kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols
  kallsyms: take the input file instead of reading stdin
  kallsyms: drop duplicated ignore patterns from kallsyms.c
  kbuild: reuse mksysmap output for kallsyms
  mksysmap: update comment about __crc_*
  kbuild: remove head-y syntax
  kbuild: use obj-y instead extra-y for objects placed at the head
  kbuild: hide error checker logs for V=1 builds
  kbuild: re-run modpost when it is updated
  kbuild: unify two modpost invocations
  kbuild: move vmlinux.o rule to the top Makefile
  kbuild: move .vmlinux.objs rule to Makefile.modpost
  kbuild: list sub-directories in ./Kbuild
  Makefile.compiler: replace cc-ifversion with compiler-specific macros
  ...
2022-10-10 12:00:45 -07:00