linux.git/arch/arm64/kernel/vdso.c, branch v6.13

arm64: vdso: Use only one single vvar mapping

2024-11-02T11:37:33+00:00

The vvar mapping is the same for all processes. Use a single mapping to
simplify the logic and align it with the other architectures.

In addition this will enable the move of the vvar handling into generic code.

Signed-off-by: Thomas Weißschuh 
Signed-off-by: Thomas Gleixner 
Tested-by: Will Deacon 
Acked-by: Will Deacon 
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-5-b64f0842d512@linutronix.de

arm64: vdso: Remove timekeeper include

2024-10-15T15:50:29+00:00

Since the generic VDSO clock mode storage is used, this header file is
unused and can be removed.

Signed-off-by: Thomas Weißschuh 
Signed-off-by: Thomas Gleixner 
Acked-by: Will Deacon 
Link: https://lore.kernel.org/all/20241010-vdso-generic-arch_update_vsyscall-v1-3-7fe5a3ea4382@linutronix.de

arm64: vDSO: Wire up getrandom() vDSO implementation

2024-09-13T15:28:36+00:00

Hook up the generic vDSO implementation to the aarch64 vDSO data page.
The _vdso_rng_data required data is placed within the _vdso_data vvar
page, by using a offset larger than the vdso_data.

The vDSO function requires a ChaCha20 implementation that does not write
to the stack, and that can do an entire ChaCha20 permutation.  The one
provided uses NEON on the permute operation, with a fallback to the
syscall for chips that do not support AdvSIMD.

This also passes the vdso_test_chacha test along with
vdso_test_getrandom. The vdso_test_getrandom bench-single result on
Neoverse-N1 shows:

   vdso: 25000000 times in 0.783884250 seconds
   libc: 25000000 times in 8.780275399 seconds
syscall: 25000000 times in 8.786581518 seconds

A small fixup to arch/arm64/include/asm/mman.h was required to avoid
pulling kernel code into the vDSO, similar to what's already done in
arch/arm64/include/asm/rwonce.h.

Signed-off-by: Adhemerval Zanella 
Reviewed-by: Ard Biesheuvel 
Acked-by: Will Deacon 
Signed-off-by: Jason A. Donenfeld

arm64: vdso: Use generic union vdso_data_store

2024-02-20T19:56:00+00:00

There is already a generic union definition for vdso_data_store in vdso
datapage header.

Use this definition to prevent code duplication.

Signed-off-by: Anna-Maria Behnsen 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Vincenzo Frascino 
Reviewed-by: Kees Cook 
Link: https://lore.kernel.org/r/20240219153939.75719-6-anna-maria@linutronix.de

arm64: Avoid cpus_have_const_cap() for ARM64_HAS_BTI

2023-10-16T13:17:04+00:00

In system_supports_bti() we use cpus_have_const_cap() to check for
ARM64_HAS_BTI, but this is not necessary and alternative_has_cap_*() or
cpus_have_final_*cap() would be preferable.

For historical reasons, cpus_have_const_cap() is more complicated than
it needs to be. Before cpucaps are finalized, it will perform a bitmap
test of the system_cpucaps bitmap, and once cpucaps are finalized it
will use an alternative branch. This used to be necessary to handle some
race conditions in the window between cpucap detection and the
subsequent patching of alternatives and static branches, where different
branches could be out-of-sync with one another (or w.r.t. alternative
sequences). Now that we use alternative branches instead of static
branches, these are all patched atomically w.r.t. one another, and there
are only a handful of cases that need special care in the window between
cpucap detection and alternative patching.

Due to the above, it would be nice to remove cpus_have_const_cap(), and
migrate callers over to alternative_has_cap_*(), cpus_have_final_cap(),
or cpus_have_cap() depending on when their requirements. This will
remove redundant instructions and improve code generation, and will make
it easier to determine how each callsite will behave before, during, and
after alternative patching.

When CONFIG_ARM64_BTI_KERNEL=y, the ARM64_HAS_BTI cpucap is a strict
boot cpu feature which is detected and patched early on the boot cpu.
All uses guarded by CONFIG_ARM64_BTI_KERNEL happen after the boot CPU
has detected ARM64_HAS_BTI and patched boot alternatives, and hence can
safely use alternative_has_cap_*() or cpus_have_final_boot_cap().

Regardless of CONFIG_ARM64_BTI_KERNEL, all other uses of ARM64_HAS_BTI
happen after system capabilities have been finalized and alternatives
have been patched. Hence these can safely use alternative_has_cap_*) or
cpus_have_final_cap().

This patch splits system_supports_bti() into system_supports_bti() and
system_supports_bti_kernel(), with the former handling where the cpucap
affects userspace functionality, and ther latter handling where the
cpucap affects kernel functionality. The use of cpus_have_const_cap() is
replaced by cpus_have_final_cap() in cpus_have_const_cap, and
cpus_have_final_boot_cap() in system_supports_bti_kernel(). This will
avoid generating code to test the system_cpucaps bitmap and should be
better for all subsequent calls at runtime. The use of
cpus_have_final_cap() and cpus_have_final_boot_cap() will make it easier
to spot if code is chaanged such that these run before the ARM64_HAS_BTI
cpucap is guaranteed to have been finalized.

Signed-off-by: Mark Rutland 
Reviewed-by: Mark Brown 
Cc: Ard Biesheuvel 
Cc: Suzuki K Poulose 
Cc: Will Deacon 
Signed-off-by: Catalin Marinas

arm64: vdso: Pass (void *) to virt_to_page()

2023-05-16T13:53:36+00:00

Like the other calls in this function virt_to_page() expects
a pointer, not an integer.

However since many architectures implement virt_to_pfn() as
a macro, this function becomes polymorphic and accepts both a
(unsigned long) and a (void *).

Fix this up with an explicit cast.

Signed-off-by: Linus Walleij 
Link: http://lists.infradead.org/pipermail/linux-arm-kernel/2023-May/832583.html
Signed-off-by: Will Deacon

mm: remove zap_page_range and create zap_vma_pages

2023-01-19T01:12:55+00:00

zap_page_range was originally designed to unmap pages within an address
range that could span multiple vmas.  While working on [1], it was
discovered that all callers of zap_page_range pass a range entirely within
a single vma.  In addition, the mmu notification call within zap_page
range does not correctly handle ranges that span multiple vmas.  When
crossing a vma boundary, a new mmu_notifier_range_init/end call pair with
the new vma should be made.

Instead of fixing zap_page_range, do the following:
- Create a new routine zap_vma_pages() that will remove all pages within
  the passed vma.  Most users of zap_page_range pass the entire vma and
  can use this new routine.
- For callers of zap_page_range not passing the entire vma, instead call
  zap_page_range_single().
- Remove zap_page_range.

[1] https://lore.kernel.org/linux-mm/20221114235507.294320-2-mike.kravetz@oracle.com/
Link: https://lkml.kernel.org/r/20230104002732.232573-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz 
Suggested-by: Peter Xu 
Acked-by: Michal Hocko 
Acked-by: Peter Xu 
Acked-by: Heiko Carstens 	[s390]
Reviewed-by: Christoph Hellwig 
Cc: Christian Borntraeger 
Cc: Christian Brauner 
Cc: Dave Hansen 
Cc: David Hildenbrand 
Cc: Eric Dumazet 
Cc: Matthew Wilcox 
Cc: Michael Ellerman 
Cc: Nadav Amit 
Cc: Palmer Dabbelt 
Cc: Rik van Riel 
Cc: Vlastimil Babka 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

vdso/timens: Refactor copy-pasted find_timens_vvar_page() helper into one copy

2022-12-01T10:35:40+00:00

find_timens_vvar_page() is not architecture-specific, as can be seen from
how all five per-architecture versions of it are the same.

(arm64, powerpc and riscv are exactly the same; x86 and s390 have two
characters difference inside a comment, less blank lines, and mark the
!CONFIG_TIME_NS version as inline.)

Refactor the five copies into a central copy in kernel/time/namespace.c.

Signed-off-by: Jann Horn 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20221130115320.2918447-1-jannh@google.com

Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-10-11T00:53:04+00:00

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
...

arm64: remove mmap linked list from vdso

2022-09-27T02:46:19+00:00

Use the VMA iterator instead.

Link: https://lkml.kernel.org/r/20220906194824.2110408-31-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Liam R. Howlett 
Acked-by: Vlastimil Babka 
Reviewed-by: Davidlohr Bueso 
Tested-by: Yu Zhao 
Cc: Catalin Marinas 
Cc: David Hildenbrand 
Cc: David Howells 
Cc: SeongJae Park 
Cc: Sven Schnelle 
Cc: Will Deacon 
Signed-off-by: Andrew Morton