Pull MM updates from Andrew Morton:
"Most of the MM queue. A few things are still pending.
Liam's maple tree rework didn't make it. This has resulted in a few
other minor patch series being held over for next time.
Multi-gen LRU still isn't merged as we were waiting for mapletree to
stabilize. The current plan is to merge MGLRU into -mm soon and to
later reintroduce mapletree, with a view to hopefully getting both
into 6.1-rc1.
Summary:
- The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve
latency and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place"
[ XFS merge from hell as per Darrick Wong in
https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]
* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
tools/testing/selftests/vm/hmm-tests.c: fix build
mm: Kconfig: fix typo
mm: memory-failure: convert to pr_fmt()
mm: use is_zone_movable_page() helper
hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
hugetlbfs: cleanup some comments in inode.c
hugetlbfs: remove unneeded header file
hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
hugetlbfs: use helper macro SZ_1{K,M}
mm: cleanup is_highmem()
mm/hmm: add a test for cross device private faults
selftests: add soft-dirty into run_vmtests.sh
selftests: soft-dirty: add test for mprotect
mm/mprotect: fix soft-dirty check in can_change_pte_writable()
mm: memcontrol: fix potential oom_lock recursion deadlock
mm/gup.c: fix formatting in check_and_migrate_movable_page()
xfs: fail dax mount if reflink is enabled on a partition
mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
userfaultfd: don't fail on unrecognized features
hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
...
Pull asm-generic updates from Arnd Bergmann:
"There are three independent sets of changes:
- Sai Prakash Ranjan adds tracing support to the asm-generic version
of the MMIO accessors, which is intended to help understand
problems with device drivers and has been part of Qualcomm's vendor
kernels for many years
- A patch from Sebastian Siewior to rework the handling of IRQ stacks
in softirqs across architectures, which is needed for enabling
PREEMPT_RT
- The last patch to remove the CONFIG_VIRT_TO_BUS option and some of
the code behind that, after the last users of this old interface
made it in through the netdev, scsi, media and staging trees"
* tag 'asm-generic-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
uapi: asm-generic: fcntl: Fix typo 'the the' in comment
arch/*/: remove CONFIG_VIRT_TO_BUS
soc: qcom: geni: Disable MMIO tracing for GENI SE
serial: qcom_geni_serial: Disable MMIO tracing for geni serial
asm-generic/io: Add logging support for MMIO accessors
KVM: arm64: Add a flag to disable MMIO trace for nVHE KVM
lib: Add register read/write tracing support
drm/meson: Fix overflow implicit truncation warnings
irqchip/tegra: Fix overflow implicit truncation warnings
coresight: etm4x: Use asm-generic IO memory barriers
arm64: io: Use asm-generic high level MMIO accessors
arch/*: Disable softirq stacks on PREEMPT_RT.
The isa_dma_bridge_buggy symbol is only used for x86_32, and only x86_32
platforms or quirks ever set it.
Add a new linux/isa-dma.h header that #defines isa_dma_bridge_buggy to 0
except on x86_32, where we keep it as a variable, and remove all the arch-
specific definitions.
[bhelgaas: commit log]
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/r/20220722214944.831438-3-shorne@gmail.com
Signed-off-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
pci_get_legacy_ide_irq() is only used on platforms that support PNP, so
many architectures define it but never use it. Replace uses of it with
ATA_PRIMARY_IRQ() and ATA_SECONDARY_IRQ(), which provide the same
functionality.
Since pci_get_legacy_ide_irq() is no longer used, remove all the
architecture-specific definitions of it as well as asm-generic/pci.h, which
only provides pci_get_legacy_ide_irq()
[bhelgaas: commit log]
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20220722214944.831438-2-shorne@gmail.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Pierre Morel <pmorel@linux.ibm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
All architecture-independent users of virt_to_bus() and bus_to_virt()
have been fixed to use the dma mapping interfaces or have been
removed now. This means the definitions on most architectures, and the
CONFIG_VIRT_TO_BUS symbol are now obsolete and can be removed.
The only exceptions to this are a few network and scsi drivers for m68k
Amiga and VME machines and ppc32 Macintosh. These drivers work correctly
with the old interfaces and are probably not worth changing.
On alpha and parisc, virt_to_bus() were still used in asm/floppy.h.
alpha can use isa_virt_to_bus() like x86 does, and parisc can just
open-code the virt_to_phys() here, as this is architecture specific
code.
I tried updating the bus-virt-phys-mapping.rst documentation, which
started as an email from Linus to explain some details of the Linux-2.0
driver interfaces. The bits about virt_to_bus() were declared obsolete
backin 2000, and the rest is not all that relevant any more, so in the
end I just decided to remove the file completely.
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Pull random number generator updates from Jason Donenfeld:
"These updates continue to refine the work began in 5.17 and 5.18 of
modernizing the RNG's crypto and streamlining and documenting its
code.
New for 5.19, the updates aim to improve entropy collection methods
and make some initial decisions regarding the "premature next" problem
and our threat model. The cloc utility now reports that random.c is
931 lines of code and 466 lines of comments, not that basic metrics
like that mean all that much, but at the very least it tells you that
this is very much a manageable driver now.
Here's a summary of the various updates:
- The random_get_entropy() function now always returns something at
least minimally useful. This is the primary entropy source in most
collectors, which in the best case expands to something like RDTSC,
but prior to this change, in the worst case it would just return 0,
contributing nothing. For 5.19, additional architectures are wired
up, and architectures that are entirely missing a cycle counter now
have a generic fallback path, which uses the highest resolution
clock available from the timekeeping subsystem.
Some of those clocks can actually be quite good, despite the CPU
not having a cycle counter of its own, and going off-core for a
stamp is generally thought to increase jitter, something positive
from the perspective of entropy gathering. Done very early on in
the development cycle, this has been sitting in next getting some
testing for a while now and has relevant acks from the archs, so it
should be pretty well tested and fine, but is nonetheless the thing
I'll be keeping my eye on most closely.
- Of particular note with the random_get_entropy() improvements is
MIPS, which, on CPUs that lack the c0 count register, will now
combine the high-speed but short-cycle c0 random register with the
lower-speed but long-cycle generic fallback path.
- With random_get_entropy() now always returning something useful,
the interrupt handler now collects entropy in a consistent
construction.
- Rather than comparing two samples of random_get_entropy() for the
jitter dance, the algorithm now tests many samples, and uses the
amount of differing ones to determine whether or not jitter entropy
is usable and how laborious it must be. The problem with comparing
only two samples was that if the cycle counter was extremely slow,
but just so happened to be on the cusp of a change, the slowness
wouldn't be detected. Taking many samples fixes that to some
degree.
This, combined with the other improvements to random_get_entropy(),
should make future unification of /dev/random and /dev/urandom
maybe more possible. At the very least, were we to attempt it again
today (we're not), it wouldn't break any of Guenter's test rigs
that broke when we tried it with 5.18. So, not today, but perhaps
down the road, that's something we can revisit.
- We attempt to reseed the RNG immediately upon waking up from system
suspend or hibernation, making use of the various timestamps about
suspend time and such available, as well as the usual inputs such
as RDRAND when available.
- Batched randomness now falls back to ordinary randomness before the
RNG is initialized. This provides more consistent guarantees to the
types of random numbers being returned by the various accessors.
- The "pre-init injection" code is now gone for good. I suspect you
in particular will be happy to read that, as I recall you
expressing your distaste for it a few months ago. Instead, to avoid
a "premature first" issue, while still allowing for maximal amount
of entropy availability during system boot, the first 128 bits of
estimated entropy are used immediately as it arrives, with the next
128 bits being buffered. And, as before, after the RNG has been
fully initialized, it winds up reseeding anyway a few seconds later
in most cases. This resulted in a pretty big simplification of the
initialization code and let us remove various ad-hoc mechanisms
like the ugly crng_pre_init_inject().
- The RNG no longer pretends to handle the "premature next" security
model, something that various academics and other RNG designs have
tried to care about in the past. After an interesting mailing list
thread, these issues are thought to be a) mainly academic and not
practical at all, and b) actively harming the real security of the
RNG by delaying new entropy additions after a potential compromise,
making a potentially bad situation even worse. As well, in the
first place, our RNG never even properly handled the premature next
issue, so removing an incomplete solution to a fake problem was
particularly nice.
This allowed for numerous other simplifications in the code, which
is a lot cleaner as a consequence. If you didn't see it before,
https://lore.kernel.org/lkml/YmlMGx6+uigkGiZ0@zx2c4.com/ may be a
thread worth skimming through.
- While the interrupt handler received a separate code path years ago
that avoids locks by using per-cpu data structures and a faster
mixing algorithm, in order to reduce interrupt latency, input and
disk events that are triggered in hardirq handlers were still
hitting locks and more expensive algorithms. Those are now
redirected to use the faster per-cpu data structures.
- Rather than having the fake-crypto almost-siphash-based random32
implementation be used right and left, and in many places where
cryptographically secure randomness is desirable, the batched
entropy code is now fast enough to replace that.
- As usual, numerous code quality and documentation cleanups. For
example, the initialization state machine now uses enum symbolic
constants instead of just hard coding numbers everywhere.
- Since the RNG initializes once, and then is always initialized
thereafter, a pretty heavy amount of code used during that
initialization is never used again. It is now completely cordoned
off using static branches and it winds up in the .text.unlikely
section so that it doesn't reduce cache compactness after the RNG
is ready.
- A variety of functions meant for waiting on the RNG to be
initialized were only used by vsprintf, and in not a particularly
optimal way. Replacing that usage with a more ordinary setup made
it possible to remove those functions.
- A cleanup of how we warn userspace about the use of uninitialized
/dev/urandom and uninitialized get_random_bytes() usage.
Interestingly, with the change you merged for 5.18 that attempts to
use jitter (but does not block if it can't), the majority of users
should never see those warnings for /dev/urandom at all now, and
the one for in-kernel usage is mainly a debug thing.
- The file_operations struct for /dev/[u]random now implements
.read_iter and .write_iter instead of .read and .write, allowing it
to also implement .splice_read and .splice_write, which makes
splice(2) work again after it was broken here (and in many other
places in the tree) during the set_fs() removal. This was a bit of
a last minute arrival from Jens that hasn't had as much time to
bake, so I'll be keeping my eye on this as well, but it seems
fairly ordinary. Unfortunately, read_iter() is around 3% slower
than read() in my tests, which I'm not thrilled about. But Jens and
Al, spurred by this observation, seem to be making progress in
removing the bottlenecks on the iter paths in the VFS layer in
general, which should remove the performance gap for all drivers.
- Assorted other bug fixes, cleanups, and optimizations.
- A small SipHash cleanup"
* tag 'random-5.19-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (49 commits)
random: check for signals after page of pool writes
random: wire up fops->splice_{read,write}_iter()
random: convert to using fops->write_iter()
random: convert to using fops->read_iter()
random: unify batched entropy implementations
random: move randomize_page() into mm where it belongs
random: remove mostly unused async readiness notifier
random: remove get_random_bytes_arch() and add rng_has_arch_random()
random: move initialization functions out of hot pages
random: make consistent use of buf and len
random: use proper return types on get_random_{int,long}_wait()
random: remove extern from functions in header
random: use static branch for crng_ready()
random: credit architectural init the exact amount
random: handle latent entropy and command line from random_init()
random: use proper jiffies comparison macro
random: remove ratelimiting for in-kernel unseeded randomness
random: move initialization out of reseeding hot path
random: avoid initializing twice in credit race
random: use symbolic constants for crng_init states
...
When call0 userspace ABI support by probing is enabled instructions that
cause illegal instruction exception when PS.WOE is clear are retried
with PS.WOE set before calling c-level exception handler. Record user pc
at which PS.WOE was set in the fast exception handler and clear PS.WOE
in the c-level exception handler if we get there from the same address.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is really not the best we can do.
Instead, at least calling random_get_entropy_fallback() would be
preferable, because that always needs to return _something_, even
falling back to jiffies eventually. It's not as though
random_get_entropy_fallback() is super high precision or guaranteed to
be entropic, but basically anything that's not zero all the time is
better than returning zero all the time.
This is accomplished by just including the asm-generic code like on
other architectures, which means we can get rid of the empty stub
function here.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Secondary reset vector is defined, compiled and used when
CONFIG_SECONDARY_RESET_VECTOR is enabled, not only on SMP.
Make declarations of _SecondaryResetVector_text_* symbols available
accordingly.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Current coprocessor support on xtensa only works correctly on
uniprocessor configurations. Make it work on SMP too and keep it lazy.
Make coprocessor_owner array per-CPU and move it to struct exc_table for
easy access from the fast_coprocessor exception handler. Allow task to
have live coprocessors only on single CPU, record this CPU number in the
struct thread_info::cp_owner_cpu. Change struct thread_info::cpenable
meaning to be 'coprocessors live on cp_owner_cpu'.
Introduce C-level coprocessor exception handler that flushes and
releases live coprocessors of the task taking 'coprocessor disabled'
exception and call it from the fast_coprocessor handler when the task
has live coprocessors on other CPU.
Make coprocessor_flush_all and coprocessor_release_all work correctly
when called from any CPU by sending IPI to the cp_owner_cpu. Add
function coprocessor_flush_release_all to do flush followed by release
atomically. Add function local_coprocessors_flush_release_all to flush
and release all coprocessors on the local CPU and use it to flush
coprocessor contexts from the CPU that goes offline.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Use xtensa_set_sr instead of inline assembly.
Rename local variable exc_table in early_trap_init to avoid conflict
with per-CPU variable of the same name.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Exception handlers are currently passed as void pointers because they
may have one or two parameters. Only two handlers uses the second
parameter and it is available in the struct pt_regs anyway. Make all
handlers have only one parameter, introduce xtensa_exception_handler
type for handlers and use it in trap_set_handler.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Drop 'extern' from all function declarations and move those that need to
be visible from traps.c to traps.h. Add 'asmlinkage' to declarations of
fucntions defined in assembly. Add 'static' to declarations and
definitions only used locally. Add argument names in declarations.
Drop unused second argument from do_multihit and do_page_fault.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Prefix arch-specific barrier macros with '__' to make use of instrumented
generic macros.
Prefix arch-specific bitops with 'arch_' to make use of instrumented
generic functions.
Provide stubs for 64-bit atomics when building with KCSAN.
Disable KCSAN instrumentation in arch/xtensa/boot.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Marco Elver <elver@google.com>
Pull tty/serial driver updates from Greg KH:
"Here are the big set of tty and serial driver changes for 5.18-rc1.
Nothing major, some more good cleanups from Jiri and 2 new serial
drivers. Highlights include:
- termbits cleanups
- export symbol cleanups and other core cleanups from Jiri Slaby
- new sunplus and mvebu uart drivers (amazing that people are still
creating new uarts...)
- samsung serial driver cleanups
- ldisc 29 is now "reserved" for experimental/development line
disciplines
- lots of other tiny fixes and cleanups to serial drivers and
bindings
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (104 commits)
vt_ioctl: fix potential spectre v1 in VT_DISALLOCATE
serial: 8250: fix XOFF/XON sending when DMA is used
tty: serial: samsung: Add ARTPEC-8 support
dt-bindings: serial: samsung: Add ARTPEC-8 UART
serial: sc16is7xx: Clear RS485 bits in the shutdown
tty: serial: samsung: simplify getting OF match data
tty: serial: samsung: constify variables and pointers
tty: serial: samsung: constify s3c24xx_serial_drv_data members
tty: serial: samsung: constify UART name
tty: serial: samsung: constify s3c24xx_serial_drv_data
tty: serial: samsung: reduce number of casts
tty: serial: samsung: embed s3c2410_uartcfg in parent structure
tty: serial: samsung: embed s3c24xx_uart_info in parent structure
serial: 8250_tegra: mark acpi_device_id as unused with !ACPI
tty: serial: bcm63xx: use more precise Kconfig symbol
serial: SERIAL_SUNPLUS should depend on ARCH_SUNPLUS
tty: serial: jsm: fix two assignments in if conditions
tty: serial: jsm: remove redundant assignments to variable linestatus
serial: 8250_mtk: make two read-only arrays static const
serial: samsung_tty: do not unlock port->lock for uart_write_wakeup()
...
Pull char/misc and other driver updates from Greg KH:
"Here is the big set of char/misc and other small driver subsystem
updates for 5.18-rc1.
Included in here are merges from driver subsystems which contain:
- iio driver updates and new drivers
- fsi driver updates
- fpga driver updates
- habanalabs driver updates and support for new hardware
- soundwire driver updates and new drivers
- phy driver updates and new drivers
- coresight driver updates
- icc driver updates
Individual changes include:
- mei driver updates
- interconnect driver updates
- new PECI driver subsystem added
- vmci driver updates
- lots of tiny misc/char driver updates
All of these have been in linux-next for a while with no reported
problems"
* tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (556 commits)
firmware: google: Properly state IOMEM dependency
kgdbts: fix return value of __setup handler
firmware: sysfb: fix platform-device leak in error path
firmware: stratix10-svc: add missing callback parameter on RSU
arm64: dts: qcom: add non-secure domain property to fastrpc nodes
misc: fastrpc: Add dma handle implementation
misc: fastrpc: Add fdlist implementation
misc: fastrpc: Add helper function to get list and page
misc: fastrpc: Add support to secure memory map
dt-bindings: misc: add fastrpc domain vmid property
misc: fastrpc: check before loading process to the DSP
misc: fastrpc: add secure domain support
dt-bindings: misc: add property to support non-secure DSP
misc: fastrpc: Add support to get DSP capabilities
misc: fastrpc: add support for FASTRPC_IOCTL_MEM_MAP/UNMAP
misc: fastrpc: separate fastrpc device from channel context
dt-bindings: nvmem: brcm,nvram: add basic NVMEM cells
dt-bindings: nvmem: make "reg" property optional
nvmem: brcm_nvram: parse NVRAM content into NVMEM cells
nvmem: dt-bindings: Fix the error of dt-bindings check
...
Merge yet more updates from Andrew Morton:
"This is the material which was staged after willystuff in linux-next.
Subsystems affected by this patch series: mm (debug, selftests,
pagecache, thp, rmap, migration, kasan, hugetlb, pagemap, madvise),
and selftests"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (113 commits)
selftests: kselftest framework: provide "finished" helper
mm: madvise: MADV_DONTNEED_LOCKED
mm: fix race between MADV_FREE reclaim and blkdev direct IO read
mm: generalize ARCH_HAS_FILTER_PGPROT
mm: unmap_mapping_range_tree() with i_mmap_rwsem shared
mm: warn on deleting redirtied only if accounted
mm/huge_memory: remove stale locking logic from __split_huge_pmd()
mm/huge_memory: remove stale page_trans_huge_mapcount()
mm/swapfile: remove stale reuse_swap_page()
mm/khugepaged: remove reuse_swap_page() usage
mm/huge_memory: streamline COW logic in do_huge_pmd_wp_page()
mm: streamline COW logic in do_swap_page()
mm: slightly clarify KSM logic in do_swap_page()
mm: optimize do_wp_page() for fresh pages in local LRU pagevecs
mm: optimize do_wp_page() for exclusive pages in the swapcache
mm/huge_memory: make is_transparent_hugepage() static
userfaultfd/selftests: enable hugetlb remap and remove event testing
selftests/vm: add hugetlb madvise MADV_DONTNEED MADV_REMOVE test
mm: enable MADV_DONTNEED for hugetlb mappings
kasan: disable LOCKDEP when printing reports
...
Pull Xtensa updates from Max Filippov:
- remove dependency on the compiler's libgcc
- allow selection of internal kernel ABI via Kconfig
- enable compiler plugins support for gcc-12 or newer
- various minor cleanups and fixes
* tag 'xtensa-20220325' of https://github.com/jcmvbkbc/linux-xtensa:
xtensa: define update_mmu_tlb function
xtensa: fix xtensa_wsr always writing 0
xtensa: enable plugin support
xtensa: clean up kernel exit assembly code
xtensa: rearrange NMI exit path
xtensa: merge stack alignment definitions
xtensa: fix DTC warning unit_address_format
xtensa: fix stop_machine_cpuslocked call in patch_text
xtensa: make secondary reset vector support conditional
xtensa: add kernel ABI selection to Kconfig
xtensa: don't link with libgcc
xtensa: add helpers for division, remainder and shifts
xtensa: add missing XCHAL_HAVE_WINDOWED check
xtensa: use XCHAL_NUM_AREGS as pt_regs::areg size
xtensa: rename PT_SIZE to PT_KERNEL_SIZE
xtensa: Remove unused early_read_config_byte() et al declarations
xtensa: use strscpy to copy strings
net: xtensa: use strscpy to copy strings
MADV_DONTNEED historically rejects mlocked ranges, but with MLOCK_ONFAULT
and MCL_ONFAULT allowing to mlock without populating, there are valid use
cases for depopulating locked ranges as well.
Users mlock memory to protect secrets. There are allocators for secure
buffers that want in-use memory generally mlocked, but cleared and
invalidated memory to give up the physical pages. This could be done with
explicit munlock -> mlock calls on free -> alloc of course, but that adds
two unnecessary syscalls, heavy mmap_sem write locks, vma splits and
re-merges - only to get rid of the backing pages.
Users also mlockall(MCL_ONFAULT) to suppress sustained paging, but are
okay with on-demand initial population. It seems valid to selectively
free some memory during the lifetime of such a process, without having to
mess with its overall policy.
Why add a separate flag? Isn't this a pretty niche usecase?
- MADV_DONTNEED has been bailing on locked vmas forever. It's at least
conceivable that someone, somewhere is relying on mlock to protect
data from perhaps broader invalidation calls. Changing this behavior
now could lead to quiet data corruption.
- It also clarifies expectations around MADV_FREE and maybe
MADV_REMOVE. It avoids the situation where one quietly behaves
different than the others. MADV_FREE_LOCKED can be added later.
- The combination of mlock() and madvise() in the first place is
probably niche. But where it happens, I'd say that dropping pages
from a locked region once they don't contain secrets or won't page
anymore is much saner than relying on mlock to protect memory from
speculative or errant invalidation calls. It's just that we can't
change the default behavior because of the two previous points.
Given that, an explicit new flag seems to make the most sense.
[hannes@cmpxchg.org: fix mips build]
Link: https://lkml.kernel.org/r/20220304171912.305060-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull flexible-array transformations from Gustavo Silva:
"Treewide patch that replaces zero-length arrays with flexible-array
members.
This has been baking in linux-next for a whole development cycle"
* tag 'flexible-array-transformations-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
treewide: Replace zero-length arrays with flexible-array members
Pull asm-generic updates from Arnd Bergmann:
"There are three sets of updates for 5.18 in the asm-generic tree:
- The set_fs()/get_fs() infrastructure gets removed for good.
This was already gone from all major architectures, but now we can
finally remove it everywhere, which loses some particularly tricky
and error-prone code. There is a small merge conflict against a
parisc cleanup, the solution is to use their new version.
- The nds32 architecture ends its tenure in the Linux kernel.
The hardware is still used and the code is in reasonable shape, but
the mainline port is not actively maintained any more, as all
remaining users are thought to run vendor kernels that would never
be updated to a future release.
- A series from Masahiro Yamada cleans up some of the uapi header
files to pass the compile-time checks"
* tag 'asm-generic-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (27 commits)
nds32: Remove the architecture
uaccess: remove CONFIG_SET_FS
ia64: remove CONFIG_SET_FS support
sh: remove CONFIG_SET_FS support
sparc64: remove CONFIG_SET_FS support
lib/test_lockup: fix kernel pointer check for separate address spaces
uaccess: generalize access_ok()
uaccess: fix type mismatch warnings from access_ok()
arm64: simplify access_ok()
m68k: fix access_ok for coldfire
MIPS: use simpler access_ok()
MIPS: Handle address errors for accesses above CPU max virtual user address
uaccess: add generic __{get,put}_kernel_nofault
nios2: drop access_ok() check from __put_user()
x86: use more conventional access_ok() definition
x86: remove __range_not_ok()
sparc64: add __{get,put}_kernel_nofault()
nds32: fix access_ok() checks in get/put_user
uaccess: fix nios2 and microblaze get_user_8()
sparc64: fix building assembly files
...
