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Merge series from Johan Hovold <johan@kernel.org>:
This series fixes device and OF node reference leaks during probe and
a clock prepare imbalance on probe failures.
Included is a related cleanup of an error path.
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That was already the limit with KASAN enabled, and the 32-bit x86 build
ends up having a couple of drm cases that have stack frames _just_ over
1kB on my allmodconfig test. So the minimal fix for this build issue
for now is to just bump the limit and make it independent of KASAN.
[ Side note: XTENSA already used 1.5k and PARISC uses 2k, so 1280 is
still relatively conservative ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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dmirror_device_init() calls device_initialize() which sets the device
reference count to 1, but fails to call put_device() when error occurs
after dev_set_name() or cdev_device_add() failures. This results in
memory leaks of struct device objects. Additionally,
dmirror_device_remove() lacks the final put_device() call to properly
release the device reference.
Found by code review.
Link: https://lkml.kernel.org/r/20251108115346.6368-1-make24@iscas.ac.cn
Fixes: 6a760f58c792 ("mm/hmm/test: use char dev with struct device to get device node")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Cc: Haoxiang Li <make24@iscas.ac.cn>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Mika Penttilä <mpenttil@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add HMM_DMIRROR_FLAG_FAIL_ALLOC flag to simulate large page allocation
failures, enabling testing of split migration code paths.
This test flag allows validation of the fallback behavior when destination
device cannot allocate compound pages. This is useful for testing the
split migration functionality.
Link: https://lkml.kernel.org/r/20251001065707.920170-13-balbirs@nvidia.com
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Implement migrate_vma_split_pages() to handle THP splitting during the
migration process when destination cannot allocate compound pages.
This addresses the common scenario where migrate_vma_setup() succeeds with
MIGRATE_PFN_COMPOUND pages, but the destination device cannot allocate
large pages during the migration phase.
Key changes:
- migrate_vma_split_pages(): Split already-isolated pages during migration
- Enhanced folio_split() and __split_unmapped_folio() with isolated
parameter to avoid redundant unmap/remap operations
This provides a fallback mechansim to ensure migration succeeds even when
large page allocation fails at the destination.
[matthew.brost@intel.com: add THP splitting during migration]
Link: https://lkml.kernel.org/r/20251120230825.181072-2-matthew.brost@intel.com
Link: https://lkml.kernel.org/r/20251001065707.920170-12-balbirs@nvidia.com
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When a zone device page is split (via huge pmd folio split). The driver
callback for folio_split is invoked to let the device driver know that the
folio size has been split into a smaller order.
Provide a default implementation for drivers that do not provide this
callback that copies the pgmap and mapping fields for the split folios.
Update the HMM test driver to handle the split.
Link: https://lkml.kernel.org/r/20251001065707.920170-11-balbirs@nvidia.com
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Enhance the hmm test driver (lib/test_hmm) with support for THP pages.
A new pool of free_folios() has now been added to the dmirror device,
which can be allocated when a request for a THP zone device private page
is made.
Add compound page awareness to the allocation function during normal
migration and fault based migration. These routines also copy
folio_nr_pages() when moving data between system memory and device memory.
args.src and args.dst used to hold migration entries are now dynamically
allocated (as they need to hold HPAGE_PMD_NR entries or more).
Split and migrate support will be added in future patches in this series.
Link: https://lkml.kernel.org/r/20251001065707.920170-10-balbirs@nvidia.com
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Change page_free to folio_free to make the folio support for
zone device-private more consistent. The PCI P2PDMA callback
has also been updated and changed to folio_free() as a result.
For drivers that do not support folios (yet), the folio is
converted back into page via &folio->page and the page is used
as is, in the current callback implementation.
Link: https://lkml.kernel.org/r/20251001065707.920170-3-balbirs@nvidia.com
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm: support device-private THP", v7.
This patch series introduces support for Transparent Huge Page (THP)
migration in zone device-private memory. The implementation enables
efficient migration of large folios between system memory and
device-private memory
Background
Current zone device-private memory implementation only supports PAGE_SIZE
granularity, leading to:
- Increased TLB pressure
- Inefficient migration between CPU and device memory
This series extends the existing zone device-private infrastructure to
support THP, leading to:
- Reduced page table overhead
- Improved memory bandwidth utilization
- Seamless fallback to base pages when needed
In my local testing (using lib/test_hmm) and a throughput test, the series
shows a 350% improvement in data transfer throughput and a 80% improvement
in latency
These patches build on the earlier posts by Ralph Campbell [1]
Two new flags are added in vma_migration to select and mark compound
pages. migrate_vma_setup(), migrate_vma_pages() and
migrate_vma_finalize() support migration of these pages when
MIGRATE_VMA_SELECT_COMPOUND is passed in as arguments.
The series also adds zone device awareness to (m)THP pages along with
fault handling of large zone device private pages. page vma walk and the
rmap code is also zone device aware. Support has also been added for
folios that might need to be split in the middle of migration (when the
src and dst do not agree on MIGRATE_PFN_COMPOUND), that occurs when src
side of the migration can migrate large pages, but the destination has not
been able to allocate large pages. The code supported and used
folio_split() when migrating THP pages, this is used when
MIGRATE_VMA_SELECT_COMPOUND is not passed as an argument to
migrate_vma_setup().
The test infrastructure lib/test_hmm.c has been enhanced to support THP
migration. A new ioctl to emulate failure of large page allocations has
been added to test the folio split code path. hmm-tests.c has new test
cases for huge page migration and to test the folio split path. A new
throughput test has been added as well.
The nouveau dmem code has been enhanced to use the new THP migration
capability.
mTHP support:
The patches hard code, HPAGE_PMD_NR in a few places, but the code has been
kept generic to support various order sizes. With additional refactoring
of the code support of different order sizes should be possible.
The future plan is to post enhancements to support mTHP with a rough
design as follows:
1. Add the notion of allowable thp orders to the HMM based test driver
2. For non PMD based THP paths in migrate_device.c, check to see if
a suitable order is found and supported by the driver
3. Iterate across orders to check the highest supported order for migration
4. Migrate and finalize
The mTHP patches can be built on top of this series, the key design
elements that need to be worked out are infrastructure and driver support
for multiple ordered pages and their migration.
HMM support for large folios was added in 10b9feee2d0d ("mm/hmm:
populate PFNs from PMD swap entry").
This patch (of 16)
Add routines to support allocation of large order zone device folios and
helper functions for zone device folios, to check if a folio is device
private and helpers for setting zone device data.
When large folios are used, the existing page_free() callback in pgmap is
called when the folio is freed, this is true for both PAGE_SIZE and higher
order pages.
Zone device private large folios do not support deferred split and scan
like normal THP folios.
Link: https://lkml.kernel.org/r/20251001065707.920170-1-balbirs@nvidia.com
Link: https://lkml.kernel.org/r/20251001065707.920170-2-balbirs@nvidia.com
Link: https://lore.kernel.org/linux-mm/20201106005147.20113-1-rcampbell@nvidia.com/ [1]
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We have two almost identical pieces that handle FORMAT_STATE_NUM case.
The differences are:
- redundant {} for one-line if-else conditional
- missing blank line after variable definitions
- inverted conditional
Unify the style of two.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20251120083140.3478507-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
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min_t(unsigned int, a, b) casts an 'unsigned long' to 'unsigned int'.
Use min(a, b) instead as it promotes any 'unsigned int' to 'unsigned long'
and so cannot discard significant bits.
In this case the 'unsigned long' value is small enough that the result
is ok.
Detected by an extra check added to min_t().
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Several parameters of the chacha20poly1305 functions require arrays of
an exact length. Use the new at_least keyword to instruct gcc and
clang to statically check that the caller is passing an object of at
least that length.
Here it is in action, with this faulty patch to wireguard's cookie.h:
struct cookie_checker {
u8 secret[NOISE_HASH_LEN];
- u8 cookie_encryption_key[NOISE_SYMMETRIC_KEY_LEN];
+ u8 cookie_encryption_key[NOISE_SYMMETRIC_KEY_LEN - 1];
u8 message_mac1_key[NOISE_SYMMETRIC_KEY_LEN];
If I try compiling this code, I get this helpful warning:
CC drivers/net/wireguard/cookie.o
drivers/net/wireguard/cookie.c: In function ‘wg_cookie_message_create’:
drivers/net/wireguard/cookie.c:193:9: warning: ‘xchacha20poly1305_encrypt’ reading 32 bytes from a region of size 31 [-Wstringop-overread]
193 | xchacha20poly1305_encrypt(dst->encrypted_cookie, cookie, COOKIE_LEN,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
194 | macs->mac1, COOKIE_LEN, dst->nonce,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
195 | checker->cookie_encryption_key);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/wireguard/cookie.c:193:9: note: referencing argument 7 of type ‘const u8 *’ {aka ‘const unsigned char *’}
In file included from drivers/net/wireguard/messages.h:10,
from drivers/net/wireguard/cookie.h:9,
from drivers/net/wireguard/cookie.c:6:
include/crypto/chacha20poly1305.h:28:6: note: in a call to function ‘xchacha20poly1305_encrypt’
28 | void xchacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20251123054819.2371989-4-Jason@zx2c4.com
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux
Pull crypto library fix from Eric Biggers:
"Fix another KMSAN warning that made it in while KMSAN wasn't working
reliably"
* tag 'libcrypto-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux:
lib/crypto: tests: Fix KMSAN warning in test_sha256_finup_2x()
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ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION provides the mechanism for
invalidating certain memory regions in a cache-incoherent manner. Currently
this is used by NVDIMM and CXL memory drivers in cases where it is
necessary to flush all data from caches by physical address range.
The operations in question are effectively memory hotplug, where stale
data might otherwise remain in the caches.
This is separate from the invalidates done to enable use of non-coherent
DMA masters, primarily in terms of when it is needed (not related to DMA
mappings) and how deep the flush must push data. The flushes done for
non-coherent DMA only need to reach the Point of Coherence of a single host
(which is often nearer CPUs and DMA masters than the physical storage).
This operation must push the data out of non architectural caches
(memory-side caches, write buffers etc) and typically all the way to the
memory device.
In some architectures these operations are supported by system components
that may become available only later in boot as they are either present
on a discoverable bus, or via a firmware description of an MMIO interface
(e.g. ACPI DSDT). Provide a framework to handle this case.
Architectures can opt in for this support via
CONFIG_GENERIC_CPU_CACHE_MAINTENANCE
Add a registration framework. Each driver provides an ops structure and
the first op is Write Back and Invalidate by PA Range. The driver may
over invalidate.
For systems that can perform this operation asynchronously an optional
completion check operation is also provided. If present that must be called
to ensure that the action has finished. This provides a considerable
performance advantage if multiple agents are involved in the maintenance
operation.
When multiple agents are present in the system each should register with
this framework and the core code will issue the invalidate to all of them
before checking for completion on each. This is done to avoid need for
filtering in the core code which can become complex when interleave,
potentially across different cache coherency hardware is going on, so it
is easier to tell everyone and let those who don't care do nothing.
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
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Fully initialize *ctx, including the buf field which sha256_init()
doesn't initialize, to avoid a KMSAN warning when comparing *ctx to
orig_ctx. This KMSAN warning slipped in while KMSAN was not working
reliably due to a stackdepot bug, which has now been fixed.
Fixes: 6733968be7cb ("lib/crypto: tests: Add tests and benchmark for sha256_finup_2x()")
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251121033431.34406-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
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Add a report_bug() variant where the bug_entry is already known. This
is useful when the exception instruction is not instantiated per-site.
But instead has a single instance. In such a case the bug_entry
address might be passed along in a known register or something.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251110115757.575795595@infradead.org
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Add BUG_FORMAT_ARGS; when an architecture is able to provide a va_list
given pt_regs, use this to print format arguments.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251110115757.457339417@infradead.org
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Add BUG_FORMAT; an architecture opt-in feature that allows adding the
WARN_printf() format string to the bug_entry table.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251110115757.223371452@infradead.org
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Bring in the UDB and objtool data annotations to avoid conflicts while further extending the bug exceptions.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
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Corrects a spelling mistake in a comment in ratelimit.c where 'seperately'
was used instead of 'separately'.
Link: https://lkml.kernel.org/r/20251119101144.3175-1-a0979625527@icloud.com
Signed-off-by: Chia-Liang Wang <a0979652527@icloud.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add a KUnit test suite to validate the base64 helpers. The tests cover
both encoding and decoding, including padded and unpadded forms as defined
by RFC 4648 (standard base64), and add negative cases for malformed inputs
and padding errors.
The test suite also validates other variants (URLSAFE, IMAP) to ensure
their correctness.
In addition to functional checks, the suite includes simple
microbenchmarks which report average encode/decode latency for small (64B)
and larger (1KB) inputs. These numbers are informational only and do not
gate the tests.
Kconfig (BASE64_KUNIT) and lib/tests/Makefile are updated accordingly.
Sample KUnit output:
KTAP version 1
# Subtest: base64
# module: base64_kunit
1..4
# base64_performance_tests: [64B] encode run : 32ns
# base64_performance_tests: [64B] decode run : 35ns
# base64_performance_tests: [1KB] encode run : 510ns
# base64_performance_tests: [1KB] decode run : 530ns
ok 1 base64_performance_tests
ok 2 base64_std_encode_tests
ok 3 base64_std_decode_tests
ok 4 base64_variant_tests
# base64: pass:4 fail:0 skip:0 total:4
# Totals: pass:4 fail:0 skip:0 total:4
Link: https://lkml.kernel.org/r/20251114060157.89507-1-409411716@gms.tku.edu.tw
Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Reviewed-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The old base64 implementation relied on a bit-accumulator loop, which was
slow for larger inputs and too permissive in validation. It would accept
extra '=', missing '=', or even '=' appearing in the middle of the input,
allowing malformed strings to pass. This patch reworks the internals to
improve performance and enforce stricter validation.
Changes:
- Encoder:
* Process input in 3-byte blocks, mapping 24 bits into four 6-bit
symbols, avoiding bit-by-bit shifting and reducing loop iterations.
* Handle the final 1-2 leftover bytes explicitly and emit '=' only when
requested.
- Decoder:
* Based on the reverse lookup tables from the previous patch, decode
input in 4-character groups.
* Each group is looked up directly, converted into numeric values, and
combined into 3 output bytes.
* Explicitly handle padded and unpadded forms:
- With padding: input length must be a multiple of 4, and '=' is
allowed only in the last two positions. Reject stray or early '='.
- Without padding: validate tail lengths (2 or 3 chars) and require
unused low bits to be zero.
* Removed the bit-accumulator style loop to reduce loop iterations.
Performance (x86_64, Intel Core i7-10700 @ 2.90GHz, avg over 1000 runs,
KUnit):
Encode:
64B ~90ns -> ~32ns (~2.8x)
1KB ~1332ns -> ~510ns (~2.6x)
Decode:
64B ~1530ns -> ~35ns (~43.7x)
1KB ~27726ns -> ~530ns (~52.3x)
[akpm@linux-foundation.org: remove u32 casts, per David and Guan-Chun]
Link: https://lkml.kernel.org/r/20251114060132.89279-1-409411716@gms.tku.edu.tw
Co-developed-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Co-developed-by: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Reviewed-by: David Laight <david.laight.linux@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Cc: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Replace the use of strchr() in base64_decode() with precomputed reverse
lookup tables for each variant. This avoids repeated string scans and
improves performance. Use -1 in the tables to mark invalid characters.
Decode:
64B ~1530ns -> ~80ns (~19.1x)
1KB ~27726ns -> ~1239ns (~22.4x)
[akpm@linux-foundation.org: fix kernedoc]
Link: https://lkml.kernel.org/r/20251114060107.89026-1-409411716@gms.tku.edu.tw
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Co-developed-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Reviewed-by: David Laight <david.laight.linux@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series " lib/base64: add generic encoder/decoder, migrate users", v5.
This series introduces a generic Base64 encoder/decoder to the kernel
library, eliminating duplicated implementations and delivering significant
performance improvements.
The Base64 API has been extended to support multiple variants (Standard,
URL-safe, and IMAP) as defined in RFC 4648 and RFC 3501. The API now
takes a variant parameter and an option to control padding. As part of
this series, users are migrated to the new interface while preserving
their specific formats: fscrypt now uses BASE64_URLSAFE, Ceph uses
BASE64_IMAP, and NVMe is updated to BASE64_STD.
On the encoder side, the implementation processes input in 3-byte blocks,
mapping 24 bits directly to 4 output symbols. This avoids bit-by-bit
streaming and reduces loop overhead, achieving about a 2.7x speedup
compared to previous implementations.
On the decoder side, replace strchr() lookups with per-variant reverse
tables and process input in 4-character groups. Each group is mapped to
numeric values and combined into 3 bytes. Padded and unpadded forms are
validated explicitly, rejecting invalid '=' usage and enforcing tail
rules. This improves throughput by ~43-52x.
This patch (of 6):
Extend the base64 API to support multiple variants (standard, URL-safe,
and IMAP) as defined in RFC 4648 and RFC 3501. The API now takes a
variant parameter and an option to control padding. Update NVMe auth code
to use the new interface with BASE64_STD.
Link: https://lkml.kernel.org/r/20251114055829.87814-1-409411716@gms.tku.edu.tw
Link: https://lkml.kernel.org/r/20251114060045.88792-1-409411716@gms.tku.edu.tw
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Co-developed-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Reviewed-by: David Laight <david.laight.linux@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yu-Sheng Huang <home7438072@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Which serves as a global default sys_info mask. When users want the same
system information for many error cases (panic, hung, lockup ...), they
can chose to set this global knob only once, while not setting up each
individual sys_info knobs.
This just adds a 'lazy' option, and doesn't change existing kernel
behavior as the mask is 0 by default.
Link: https://lkml.kernel.org/r/20251113111039.22701-5-feng.tang@linux.alibaba.com
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This reverts commit 7abcb84f953df037d40fad66f2109db318dd155b.
The introduction of WRITE_ONCE() calls for the 'prev' and 'next' variables
inside plist_check_list() was a misapplication. WRITE_ONCE() is
fundamentally a compiler barrier designed to prevent compiler
optimizations (like caching or reordering) on shared memory locations.
However, the variables 'prev' and 'next' are local, stack-allocated
pointers accessed only by the current thread's invocation of the function.
Since these pointers are thread-local and are never accessed concurrently,
applying WRITE_ONCE() to them is semantically incorrect and unnecessary.
Furthermore, the use of WRITE_ONCE() on local variables prevents the
compiler from performing standard optimizations, such as keeping these
variables cached solely in CPU registers throughout the loop, potentially
introducing performance overhead. Restore the conventional C assignment
for local loop variables, allowing the compiler to generate optimal code.
Link: https://lkml.kernel.org/r/20251113193413.499309-1-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: I Hsin Cheng <richard120310@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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There are slight differences in the mul_u64_add_u64_div_u64() code between
32bit and 64bit systems.
Compile and test the 32bit version on 64bit hosts for better test
coverage.
Link: https://lkml.kernel.org/r/20251105201035.64043-10-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Replace the bit by bit algorithm with one that generates 16 bits per
iteration on 32bit architectures and 32 bits on 64bit ones.
On my zen 5 this reduces the time for the tests (using the generic code)
from ~3350ns to ~1000ns.
Running the 32bit algorithm on 64bit x86 takes ~1500ns. It'll be slightly
slower on a real 32bit system, mostly due to register pressure.
The savings for 32bit x86 are much higher (tested in userspace). The
worst case (lots of bits in the quotient) drops from ~900 clocks to ~130
(pretty much independant of the arguments). Other 32bit architectures may
see better savings.
It is possibly to optimise for divisors that span less than
__LONG_WIDTH__/2 bits. However I suspect they don't happen that often and
it doesn't remove any slow cpu divide instructions which dominate the
result.
Typical improvements for 64bit random divides:
old new
sandy bridge: 470 150
haswell: 400 144
piledriver: 960 467 I think rdpmc is very slow.
zen5: 244 80
(Timing is 'rdpmc; mul_div(); rdpmc' with the multiply depending on the
first rdpmc and the second rdpmc depending on the quotient.)
Object code (64bit x86 test program): old 0x173 new 0x141.
Link: https://lkml.kernel.org/r/20251105201035.64043-9-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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gcc generates horrid code for both ((u64)u32_a * u32_b) and (u64_a +
u32_b). As well as the extra instructions it can generate a lot of spills
to stack (including spills of constant zeros and even multiplies by
constant zero).
mul_u32_u32() already exists to optimise the multiply. Add a similar
add_u64_32() for the addition. Disable both for clang - it generates
better code without them.
Move the 64x64 => 128 multiply into a static inline helper function for
code clarity. No need for the a/b_hi/lo variables, the implicit casts on
the function calls do the work for us. Should have minimal effect on the
generated code.
Use mul_u32_u32() and add_u64_u32() in the 64x64 => 128 multiply in
mul_u64_add_u64_div_u64().
Link: https://lkml.kernel.org/r/20251105201035.64043-8-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Change the #if in div64.c so that test_mul_u64_u64_div_u64.c can compile
and test the generic version (including the 'long multiply') on
architectures (eg amd64) that define their own copy.
Test the kernel version and the locally compiled version on all arch.
Output the time taken (in ns) on the 'test completed' trace.
For reference, on my zen 5, the optimised version takes ~220ns and the
generic version ~3350ns. Using the native multiply saves ~200ns and
adding back the ilog2() 'optimisation' test adds ~50ms.
Link: https://lkml.kernel.org/r/20251105201035.64043-7-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Replicate the existing mul_u64_u64_div_u64() test cases with round up.
Update the shell script that verifies the table, remove the comment
markers so that it can be directly pasted into a shell.
Rename the divisor from 'c' to 'd' to match mul_u64_add_u64_div_u64().
It any tests fail then fail the module load with -EINVAL.
Link: https://lkml.kernel.org/r/20251105201035.64043-6-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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The existing mul_u64_u64_div_u64() rounds down, a 'rounding up' variant
needs 'divisor - 1' adding in between the multiply and divide so cannot
easily be done by a caller.
Add mul_u64_add_u64_div_u64(a, b, c, d) that calculates (a * b + c)/d and
implement the 'round down' and 'round up' using it.
Update the x86-64 asm to optimise for 'c' being a constant zero.
Add kerndoc definitions for all three functions.
Link: https://lkml.kernel.org/r/20251105201035.64043-5-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
If the product is only 64bits div64_u64() can be used for the divide.
Replace the pre-multiply check (ilog2(a) + ilog2(b) <= 62) with a simple
post-multiply check that the high 64bits are zero.
This has the advantage of being simpler, more accurate and less code. It
will always be faster when the product is larger than 64bits.
Most 64bit cpu have a native 64x64=128 bit multiply, this is needed (for
the low 64bits) even when div64_u64() is called - so the early check gains
nothing and is just extra code.
32bit cpu will need a compare (etc) to generate the 64bit ilog2() from two
32bit bit scans - so that is non-trivial. (Never mind the mess of x86's
'bsr' and any oddball cpu without fast bit-scan instructions.) Whereas the
additional instructions for the 128bit multiply result are pretty much one
multiply and two adds (typically the 'adc $0,%reg' can be run in parallel
with the instruction that follows).
The only outliers are 64bit systems without 128bit mutiply and simple in
order 32bit ones with fast bit scan but needing extra instructions to get
the high bits of the multiply result. I doubt it makes much difference to
either, the latter is definitely not mainstream.
If anyone is worried about the analysis they can look at the generated
code for x86 (especially when cmov isn't used).
Link: https://lkml.kernel.org/r/20251105201035.64043-4-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Since the overflow check always triggers when the divisor is zero
move the check for divide by zero inside the overflow check.
This means there is only one test in the normal path.
Link: https://lkml.kernel.org/r/20251105201035.64043-3-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Implement mul_u64_u64_div_u64_roundup()", v5.
The pwm-stm32.c code wants a 'rounding up' version of
mul_u64_u64_div_u64(). This can be done simply by adding 'divisor - 1' to
the 128bit product. Implement mul_u64_add_u64_div_u64(a, b, c, d) = (a *
b + c)/d based on the existing code. Define mul_u64_u64_div_u64(a, b, d)
as mul_u64_add_u64_div_u64(a, b, 0, d) and mul_u64_u64_div_u64_roundup(a,
b, d) as mul_u64_add_u64_div_u64(a, b, d-1, d).
Only x86-64 has an optimsed (asm) version of the function. That is
optimised to avoid the 'add c' when c is known to be zero. In all other
cases the extra code will be noise compared to the software divide code.
The test module has been updated to test mul_u64_u64_div_u64_roundup() and
also enhanced it to verify the C division code on x86-64 and the 32bit
division code on 64bit.
This patch (of 9):
Change to prototype from mul_u64_u64_div_u64(u64 a, u64 b, u64 c) to
mul_u64_u64_div_u64(u64 a, u64 b, u64 d). Using 'd' for 'divisor' makes
more sense.
An upcoming change adds a 'c' parameter to calculate (a * b + c)/d.
Link: https://lkml.kernel.org/r/20251105201035.64043-1-david.laight.linux@gmail.com
Link: https://lkml.kernel.org/r/20251105201035.64043-2-david.laight.linux@gmail.com
Signed-off-by: David Laight <david.laight.linux@gmail.com>
Reviewed-by: Nicolas Pitre <npitre@baylibre.com>
Cc: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Simplify formulations, correct flow, split it into proper paragraphs and
update structure.
No functional changes.
Link: https://lkml.kernel.org/r/20251029122743.1110-1-bp@kernel.org
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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For the sake of the code readability and easier maintenance factor out
read and write sys_info handlers.
[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20251030132007.3742368-7-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Feng Tang <feng.tang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The both handlers use the local 'table' variable and assign the same data
to it, deduplicate that.
Link: https://lkml.kernel.org/r/20251030132007.3742368-6-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Feng Tang <feng.tang@linux.alibaba.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Compiler was not happy about dead variable in use:
lib/sys_info.c:52:19: error: variable 'sys_info_avail' is not needed and will not be emitted [-Werror,-Wunneeded-internal-declaration]
52 | static const char sys_info_avail[] = "tasks,mem,timers,locks,ftrace,all_bt,blocked_tasks";
| ^~~~~~~~~~~~~~
This was fixed by adding __maybe_unused attribute that just hides the
issue and didn't actually fix the root cause. Rewrite the fix by moving
the local variable from stack to a heap.
As a side effect this drops unneeded "synchronisation" of duplicative info
and also makes code ready for the further refactoring.
Link: https://lkml.kernel.org/r/20251030132007.3742368-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Feng Tang <feng.tang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There is no need to keep a custom structure just for the need of a plain
array of strings. Replace struct sys_info_name with plain array of
strings.
With that done, simplify the code, in particular, naturally use
for_each_set_bit() when iterating over si_bits_global bitmap.
Link: https://lkml.kernel.org/r/20251030132007.3742368-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Feng Tang <feng.tang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Align constant definition names with parameters to make it easier to map.
It's also better to maintain and extend the names while keeping their
uniqueness.
Link: https://lkml.kernel.org/r/20251030132007.3742368-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Feng Tang <feng.tang@linux.alibaba.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "panic: sys_info: Refactor and fix a potential issue", v3.
While targeting the compilation issue due to dangling variable, I have
noticed more opportunities for refactoring that helps to avoid above
mentioned compilation issue in a cleaner way and also fixes a potential
problem with global variable access.
This patch (of 6):
The for-loop might re-read the content of the memory the si_bits_global
points to on each iteration. Instead, just capture it for the sake of
consistency and use that instead.
Link: https://lkml.kernel.org/r/20251030132007.3742368-1-andriy.shevchenko@linux.intel.com
Link: https://lkml.kernel.org/r/20251030132007.3742368-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Feng Tang <feng.tang@linux.alibaba.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The %pe format specifier is designed to print error pointers. It prints a
symbolic error name (eg. -EINVAL) and it makes the code simpler by
omitting PTR_ERR();
This patch fixes this cocci report:
lib/alloc_tag.c:776:63-70: WARNING: Consider using %pe to print PTR_ERR()
Link: https://lkml.kernel.org/r/20251105023925.1447482-1-zeng_chi911@163.com
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Merge series from Bartosz Golaszewski <brgl@bgdev.pl>:
Problem statement: GPIOs are implemented as a strictly exclusive
resource in the kernel but there are lots of platforms on which single
pin is shared by multiple devices which don't communicate so need some
way of properly sharing access to a GPIO. What we have now is the
GPIOD_FLAGS_BIT_NONEXCLUSIVE flag which was introduced as a hack and
doesn't do any locking or arbitration of access - it literally just hand
the same GPIO descriptor to all interested users.
The proposed solution is composed of three major parts: the high-level,
shared GPIO proxy driver that arbitrates access to the shared pin and
exposes a regular GPIO chip interface to consumers, a low-level shared
GPIOLIB module that scans firmware nodes and creates auxiliary devices
that attach to the proxy driver and finally a set of core GPIOLIB
changes that plug the former into the GPIO lookup path.
The changes are implemented in a way that allows to seamlessly compile
out any code related to sharing GPIOs for systems that don't need it.
The practical use-case for this are the powerdown GPIOs shared by
speakers on Qualcomm db845c platform, however I have also extensively
tested it using gpio-virtuser on arm64 qemu with various DT
configurations.
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CID management OR's two cpumasks and then calculates the weight on the
result. That's inefficient as that has to walk the same stuff twice. As
this is done with runqueue lock held, there is a real benefit of speeding
this up. Depending on the system this results in 10-20% less cycles spent
with runqueue lock held for a 4K cpumask.
Provide cpumask_weighted_or() and the corresponding bitmap functions which
return the weight of the OR result right away.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251119172549.448263340@linutronix.de
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Add RISC-V code to be compiled to allow the userspace raid6test program
to be built and run on RISC-V.
Signed-off-by: Chunyan Zhang <zhang.lyra@gmail.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://patch.msgid.link/20250718072711.3865118-6-zhangchunyan@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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To support userspace raid6test, this patch adds __KERNEL__ ifdef for kernel
header inclusions also userspace wrapper definitions to allow code to be
compiled in userspace.
This patch also drops the NSIZE macro, instead of using the vector length,
which can work for both kernel and user space.
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Chunyan Zhang <zhangchunyan@iscas.ac.cn>
Link: https://patch.msgid.link/20250718072711.3865118-5-zhangchunyan@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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To prevent the compiler from breaking the inline vector assembly code,
this code must be built without compiler support for vector.
Signed-off-by: Chunyan Zhang <zhangchunyan@iscas.ac.cn>
Link: https://patch.msgid.link/20250718072711.3865118-4-zhangchunyan@iscas.ac.cn
[pjw@kernel.org: cleaned up commit message]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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A handful drivers want to print a content of the struct timespec64
in a format of %lld:%09ld. In order to make their lives easier, add
the respecting specifier directly to the printf() implementation.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20251113150217.3030010-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
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Two functions use the same specifier data for the special hex number.
Almost the same as the field width is calculated on the size of the
given type. Due to that, make a compound literal macro in order to
deduplicate the rest.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20251113150313.3030700-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
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