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Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Linus Torvalds
|
6a08076f00 |
Merge tag 's390-7.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Alexander Gordeev: - Enable IOMMUFD and VFIO cdev such that PCI pass-through to QEMU/KVM can optionally utilize native IOMMUFD - With HAVE_ARCH_BUG_FORMAT enabled the BUG infrastructure might misinterpret flags or fault. Fix this by moving the "format" field emission into __BUG_ENTRY() - The generic version of _THIS_IP_ is known to be brittle and may break with current and future GCC and Clang optimizations. Fix it by overriding _THIS_IP_ * tag 's390-7.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390: Implement _THIS_IP_ using inline asm s390/bug: Always emit format word in __BUG_ENTRY s390/configs: Enable IOMMUFD and VFIO cdev in defconfigs |
||
  Marco ElverandAlexander Gordeev
|
7c6535c37d |
s390: Implement _THIS_IP_ using inline asm
Both GCC [1] and Clang [2] consider the generic version of _THIS_IP_ to
be broken:
#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
In particular, the address of a label is only expected to be used with a
computed goto.
While the generic version more or less works today, it is known to be
brittle and may break with current and future optimizations. For
example, Clang -O2 always returns 1 when this function is inlined:
static inline unsigned long get_ip(void)
{ return ({ __label__ __here; __here: (unsigned long)&&__here; }); }
Fix it by overriding _THIS_IP_ in <asm/linkage.h> (which is included by
<linux/instruction_pointer.h>) using an architecture-specific inline asm
version. Additionally, avoiding taking the address of a label prevents
compilers from emitting spurious indirect branch targets (e.g. ENDBR or
BTI) under control-flow integrity schemes.
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120071 [1]
Link: https://github.com/llvm/llvm-project/issues/138272 [2]
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
|
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 Jan PolenskyandAlexander Gordeev
|
3daad7f60a |
s390/bug: Always emit format word in __BUG_ENTRY
When CONFIG_DEBUG_BUGVERBOSE is disabled, the s390 __BUG_ENTRY() macro
omits the format string pointer, so the generated __bug_table entry no
longer matches struct bug_entry.
With HAVE_ARCH_BUG_FORMAT enabled, the generic BUG infrastructure reads
bug_entry::format via bug_get_format(). If the format word is missing,
subsequent fields are read from the wrong offset, which may:
- Misinterpret flags (BUG vs WARN classification errors)
- Fault when dereferencing a misread format pointer
The root cause is that __BUG_ENTRY() delegates format word emission to
__BUG_ENTRY_VERBOSE(), which is conditional on CONFIG_DEBUG_BUGVERBOSE.
Fix this by moving the format field emission directly into __BUG_ENTRY()
so it is always emitted unconditionally. Remove the format parameter from
__BUG_ENTRY_VERBOSE() and keep only file/line emission conditional on
CONFIG_DEBUG_BUGVERBOSE.
Fixes:
|
||
  Masami Hiramatsu (Google)andSteven Rostedt
|
a494d3c8d5 |
ring-buffer: Flush and stop persistent ring buffer on panic
On real hardware, panic and machine reboot may not flush hardware cache
to memory. This means the persistent ring buffer, which relies on a
coherent state of memory, may not have its events written to the buffer
and they may be lost. Moreover, there may be inconsistency with the
counters which are used for validation of the integrity of the
persistent ring buffer which may cause all data to be discarded.
To avoid this issue, stop recording of the ring buffer on panic and
flush the cache of the ring buffer's memory.
Fixes:
|
||
|
Linus Torvalds
|
2a4c0c11c0 |
Merge tag 's390-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Vasily Gorbik: - Add support for CONFIG_PAGE_TABLE_CHECK and enable it in debug_defconfig. s390 can only tell user from kernel PTEs via the mm, so mm_struct is now passed into pxx_user_accessible_page() callbacks - Expose the PCI function UID as an arch-specific slot attribute in sysfs so a function can be identified by its user-defined id while still in standby. Introduces a generic ARCH_PCI_SLOT_GROUPS hook in drivers/pci/slot.c - Refresh s390 PCI documentation to reflect current behavior and cover previously undocumented sysfs attributes - zcrypt device driver cleanup series: consistent field types, clearer variable naming, a kernel-doc warning fix, and a comment explaining the intentional synchronize_rcu() in pkey_handler_register() - Provide an s390 arch_raw_cpu_ptr() that avoids the detour via get_lowcore() using alternatives, shrinking defconfig by ~27 kB - Guard identity-base randomization with kaslr_enabled() so nokaslr keeps the identity mapping at 0 even with RANDOMIZE_IDENTITY_BASE=y - Build S390_MODULES_SANITY_TEST as a module only by requiring KUNIT && m, since built-in would not exercise module loading - Remove the permanently commented-out HMCDRV_DEV_CLASS create_class() code in the hmcdrv driver - Drop stale ident_map_size extern conflicting with asm/page.h * tag 's390-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/zcrypt: Fix warning about wrong kernel doc comment PCI: s390: Expose the UID as an arch specific PCI slot attribute docs: s390/pci: Improve and update PCI documentation s390/pkey: Add comment about synchronize_rcu() to pkey base s390/hmcdrv: Remove commented out code s390/zcrypt: Slight rework on the agent_id field s390/zcrypt: Explicitly use a card variable in _zcrypt_send_cprb s390/zcrypt: Rework MKVP fields and handling s390/zcrypt: Make apfs a real unsigned int field s390/zcrypt: Rework domain processing within zcrypt device driver s390/zcrypt: Move inline function rng_type6cprb_msgx from header to code s390/percpu: Provide arch_raw_cpu_ptr() s390: Enable page table check for debug_defconfig s390/pgtable: Add s390 support for page table check s390/pgtable: Use set_pmd_bit() to invalidate PMD entry mm/page_table_check: Pass mm_struct to pxx_user_accessible_page() s390/boot: Respect kaslr_enabled() for identity randomization s390/Kconfig: Make modules sanity test a module-only option s390/setup: Drop stale ident_map_size declaration |
||
|
Linus Torvalds
|
01f492e181 |
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"Arm:
- Add support for tracing in the standalone EL2 hypervisor code,
which should help both debugging and performance analysis. This
uses the new infrastructure for 'remote' trace buffers that can be
exposed by non-kernel entities such as firmware, and which came
through the tracing tree
- Add support for GICv5 Per Processor Interrupts (PPIs), as the
starting point for supporting the new GIC architecture in KVM
- Finally add support for pKVM protected guests, where pages are
unmapped from the host as they are faulted into the guest and can
be shared back from the guest using pKVM hypercalls. Protected
guests are created using a new machine type identifier. As the
elusive guestmem has not yet delivered on its promises, anonymous
memory is also supported
This is only a first step towards full isolation from the host; for
example, the CPU register state and DMA accesses are not yet
isolated. Because this does not really yet bring fully what it
promises, it is hidden behind CONFIG_ARM_PKVM_GUEST +
'kvm-arm.mode=protected', and also triggers TAINT_USER when a VM is
created. Caveat emptor
- Rework the dreaded user_mem_abort() function to make it more
maintainable, reducing the amount of state being exposed to the
various helpers and rendering a substantial amount of state
immutable
- Expand the Stage-2 page table dumper to support NV shadow page
tables on a per-VM basis
- Tidy up the pKVM PSCI proxy code to be slightly less hard to
follow
- Fix both SPE and TRBE in non-VHE configurations so that they do not
generate spurious, out of context table walks that ultimately lead
to very bad HW lockups
- A small set of patches fixing the Stage-2 MMU freeing in error
cases
- Tighten-up accepted SMC immediate value to be only #0 for host
SMCCC calls
- The usual cleanups and other selftest churn
LoongArch:
- Use CSR_CRMD_PLV for kvm_arch_vcpu_in_kernel()
- Add DMSINTC irqchip in kernel support
RISC-V:
- Fix steal time shared memory alignment checks
- Fix vector context allocation leak
- Fix array out-of-bounds in pmu_ctr_read() and pmu_fw_ctr_read_hi()
- Fix double-free of sdata in kvm_pmu_clear_snapshot_area()
- Fix integer overflow in kvm_pmu_validate_counter_mask()
- Fix shift-out-of-bounds in make_xfence_request()
- Fix lost write protection on huge pages during dirty logging
- Split huge pages during fault handling for dirty logging
- Skip CSR restore if VCPU is reloaded on the same core
- Implement kvm_arch_has_default_irqchip() for KVM selftests
- Factored-out ISA checks into separate sources
- Added hideleg to struct kvm_vcpu_config
- Factored-out VCPU config into separate sources
- Support configuration of per-VM HGATP mode from KVM user space
s390:
- Support for ESA (31-bit) guests inside nested hypervisors
- Remove restriction on memslot alignment, which is not needed
anymore with the new gmap code
- Fix LPSW/E to update the bear (which of course is the breaking
event address register)
x86:
- Shut up various UBSAN warnings on reading module parameter before
they were initialized
- Don't zero-allocate page tables that are used for splitting
hugepages in the TDP MMU, as KVM is guaranteed to set all SPTEs in
the page table and thus write all bytes
- As an optimization, bail early when trying to unsync 4KiB mappings
if the target gfn can just be mapped with a 2MiB hugepage
x86 generic:
- Copy single-chunk MMIO write values into struct kvm_vcpu (more
precisely struct kvm_mmio_fragment) to fix use-after-free stack
bugs where KVM would dereference stack pointer after an exit to
userspace
- Clean up and comment the emulated MMIO code to try to make it
easier to maintain (not necessarily "easy", but "easier")
- Move VMXON+VMXOFF and EFER.SVME toggling out of KVM (not *all* of
VMX and SVM enabling) as it is needed for trusted I/O
- Advertise support for AVX512 Bit Matrix Multiply (BMM) instructions
- Immediately fail the build if a required #define is missing in one
of KVM's headers that is included multiple times
- Reject SET_GUEST_DEBUG with -EBUSY if there's an already injected
exception, mostly to prevent syzkaller from abusing the uAPI to
trigger WARNs, but also because it can help prevent userspace from
unintentionally crashing the VM
- Exempt SMM from CPUID faulting on Intel, as per the spec
- Misc hardening and cleanup changes
x86 (AMD):
- Fix and optimize IRQ window inhibit handling for AVIC; make it
per-vCPU so that KVM doesn't prematurely re-enable AVIC if multiple
vCPUs have to-be-injected IRQs
- Clean up and optimize the OSVW handling, avoiding a bug in which
KVM would overwrite state when enabling virtualization on multiple
CPUs in parallel. This should not be a problem because OSVW should
usually be the same for all CPUs
- Drop a WARN in KVM_MEMORY_ENCRYPT_REG_REGION where KVM complains
about a "too large" size based purely on user input
- Clean up and harden the pinning code for KVM_MEMORY_ENCRYPT_REG_REGION
- Disallow synchronizing a VMSA of an already-launched/encrypted
vCPU, as doing so for an SNP guest will crash the host due to an
RMP violation page fault
- Overhaul KVM's APIs for detecting SEV+ guests so that VM-scoped
queries are required to hold kvm->lock, and enforce it by lockdep.
Fix various bugs where sev_guest() was not ensured to be stable for
the whole duration of a function or ioctl
- Convert a pile of kvm->lock SEV code to guard()
- Play nicer with userspace that does not enable
KVM_CAP_EXCEPTION_PAYLOAD, for which KVM needs to set CR2 and DR6
as a response to ioctls such as KVM_GET_VCPU_EVENTS (even if the
payload would end up in EXITINFO2 rather than CR2, for example).
Only set CR2 and DR6 when consumption of the payload is imminent,
but on the other hand force delivery of the payload in all paths
where userspace retrieves CR2 or DR6
- Use vcpu->arch.cr2 when updating vmcb12's CR2 on nested #VMEXIT
instead of vmcb02->save.cr2. The value is out of sync after a
save/restore or after a #PF is injected into L2
- Fix a class of nSVM bugs where some fields written by the CPU are
not synchronized from vmcb02 to cached vmcb12 after VMRUN, and so
are not up-to-date when saved by KVM_GET_NESTED_STATE
- Fix a class of bugs where the ordering between KVM_SET_NESTED_STATE
and KVM_SET_{S}REGS could cause vmcb02 to be incorrectly
initialized after save+restore
- Add a variety of missing nSVM consistency checks
- Fix several bugs where KVM failed to correctly update VMCB fields
on nested #VMEXIT
- Fix several bugs where KVM failed to correctly synthesize #UD or
#GP for SVM-related instructions
- Add support for save+restore of virtualized LBRs (on SVM)
- Refactor various helpers and macros to improve clarity and
(hopefully) make the code easier to maintain
- Aggressively sanitize fields when copying from vmcb12, to guard
against unintentionally allowing L1 to utilize yet-to-be-defined
features
- Fix several bugs where KVM botched rAX legality checks when
emulating SVM instructions. There are remaining issues in that KVM
doesn't handle size prefix overrides for 64-bit guests
- Fail emulation of VMRUN/VMLOAD/VMSAVE if mapping vmcb12 fails
instead of somewhat arbitrarily synthesizing #GP (i.e. don't double
down on AMD's architectural but sketchy behavior of generating #GP
for "unsupported" addresses)
- Cache all used vmcb12 fields to further harden against TOCTOU bugs
x86 (Intel):
- Drop obsolete branch hint prefixes from the VMX instruction macros
- Use ASM_INPUT_RM() in __vmcs_writel() to coerce clang into using a
register input when appropriate
- Code cleanups
guest_memfd:
- Don't mark guest_memfd folios as accessed, as guest_memfd doesn't
support reclaim, the memory is unevictable, and there is no storage
to write back to
LoongArch selftests:
- Add KVM PMU test cases
s390 selftests:
- Enable more memory selftests
x86 selftests:
- Add support for Hygon CPUs in KVM selftests
- Fix a bug in the MSR test where it would get false failures on
AMD/Hygon CPUs with exactly one of RDPID or RDTSCP
- Add an MADV_COLLAPSE testcase for guest_memfd as a regression test
for a bug where the kernel would attempt to collapse guest_memfd
folios against KVM's will"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (373 commits)
KVM: x86: use inlines instead of macros for is_sev_*guest
x86/virt: Treat SVM as unsupported when running as an SEV+ guest
KVM: SEV: Goto an existing error label if charging misc_cg for an ASID fails
KVM: SVM: Move lock-protected allocation of SEV ASID into a separate helper
KVM: SEV: use mutex guard in snp_handle_guest_req()
KVM: SEV: use mutex guard in sev_mem_enc_unregister_region()
KVM: SEV: use mutex guard in sev_mem_enc_ioctl()
KVM: SEV: use mutex guard in snp_launch_update()
KVM: SEV: Assert that kvm->lock is held when querying SEV+ support
KVM: SEV: Document that checking for SEV+ guests when reclaiming memory is "safe"
KVM: SEV: Hide "struct kvm_sev_info" behind CONFIG_KVM_AMD_SEV=y
KVM: SEV: WARN on unhandled VM type when initializing VM
KVM: LoongArch: selftests: Add PMU overflow interrupt test
KVM: LoongArch: selftests: Add basic PMU event counting test
KVM: LoongArch: selftests: Add cpucfg read/write helpers
LoongArch: KVM: Add DMSINTC inject msi to vCPU
LoongArch: KVM: Add DMSINTC device support
LoongArch: KVM: Make vcpu_is_preempted() as a macro rather than function
LoongArch: KVM: Move host CSR_GSTAT save and restore in context switch
LoongArch: KVM: Move host CSR_EENTRY save and restore in context switch
...
|
||
|
Linus Torvalds
|
440d6635b2 |
Merge tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- "pid: make sub-init creation retryable" (Oleg Nesterov)
Make creation of init in a new namespace more robust by clearing away
some historical cruft which is no longer needed. Also some
documentation fixups
- "selftests/fchmodat2: Error handling and general" (Mark Brown)
Fix and a cleanup for the fchmodat2() syscall selftest
- "lib: polynomial: Move to math/ and clean up" (Andy Shevchenko)
- "hung_task: Provide runtime reset interface for hung task detector"
(Aaron Tomlin)
Give administrators the ability to zero out
/proc/sys/kernel/hung_task_detect_count
- "tools/getdelays: use the static UAPI headers from
tools/include/uapi" (Thomas Weißschuh)
Teach getdelays to use the in-kernel UAPI headers rather than the
system-provided ones
- "watchdog/hardlockup: Improvements to hardlockup" (Mayank Rungta)
Several cleanups and fixups to the hardlockup detector code and its
documentation
- "lib/bch: fix undefined behavior from signed left-shifts" (Josh Law)
A couple of small/theoretical fixes in the bch code
- "ocfs2/dlm: fix two bugs in dlm_match_regions()" (Junrui Luo)
- "cleanup the RAID5 XOR library" (Christoph Hellwig)
A quite far-reaching cleanup to this code. I can't do better than to
quote Christoph:
"The XOR library used for the RAID5 parity is a bit of a mess right
now. The main file sits in crypto/ despite not being cryptography
and not using the crypto API, with the generic implementations
sitting in include/asm-generic and the arch implementations
sitting in an asm/ header in theory. The latter doesn't work for
many cases, so architectures often build the code directly into
the core kernel, or create another module for the architecture
code.
Change this to a single module in lib/ that also contains the
architecture optimizations, similar to the library work Eric
Biggers has done for the CRC and crypto libraries later. After
that it changes to better calling conventions that allow for
smarter architecture implementations (although none is contained
here yet), and uses static_call to avoid indirection function call
overhead"
- "lib/list_sort: Clean up list_sort() scheduling workarounds"
(Kuan-Wei Chiu)
Clean up this library code by removing a hacky thing which was added
for UBIFS, which UBIFS doesn't actually need
- "Fix bugs in extract_iter_to_sg()" (Christian Ehrhardt)
Fix a few bugs in the scatterlist code, add in-kernel tests for the
now-fixed bugs and fix a leak in the test itself
- "kdump: Enable LUKS-encrypted dump target support in ARM64 and
PowerPC" (Coiby Xu)
Enable support of the LUKS-encrypted device dump target on arm64 and
powerpc
- "ocfs2: consolidate extent list validation into block read callbacks"
(Joseph Qi)
Cleanup, simplify, and make more robust ocfs2's validation of extent
list fields (Kernel test robot loves mounting corrupted fs images!)
* tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (127 commits)
ocfs2: validate group add input before caching
ocfs2: validate bg_bits during freefrag scan
ocfs2: fix listxattr handling when the buffer is full
doc: watchdog: fix typos etc
update Sean's email address
ocfs2: use get_random_u32() where appropriate
ocfs2: split transactions in dio completion to avoid credit exhaustion
ocfs2: remove redundant l_next_free_rec check in __ocfs2_find_path()
ocfs2: validate extent block list fields during block read
ocfs2: remove empty extent list check in ocfs2_dx_dir_lookup_rec()
ocfs2: validate dx_root extent list fields during block read
ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY
ocfs2: handle invalid dinode in ocfs2_group_extend
.get_maintainer.ignore: add Askar
ocfs2: validate bg_list extent bounds in discontig groups
checkpatch: exclude forward declarations of const structs
tools/accounting: handle truncated taskstats netlink messages
taskstats: set version in TGID exit notifications
ocfs2/heartbeat: fix slot mapping rollback leaks on error paths
arm64,ppc64le/kdump: pass dm-crypt keys to kdump kernel
...
|
||
|
Linus Torvalds
|
334fbe734e |
Merge tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton: - "maple_tree: Replace big node with maple copy" (Liam Howlett) Mainly prepararatory work for ongoing development but it does reduce stack usage and is an improvement. - "mm, swap: swap table phase III: remove swap_map" (Kairui Song) Offers memory savings by removing the static swap_map. It also yields some CPU savings and implements several cleanups. - "mm: memfd_luo: preserve file seals" (Pratyush Yadav) File seal preservation to LUO's memfd code - "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan Chen) Additional userspace stats reportng to zswap - "arch, mm: consolidate empty_zero_page" (Mike Rapoport) Some cleanups for our handling of ZERO_PAGE() and zero_pfn - "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu Han) A robustness improvement and some cleanups in the kmemleak code - "Improve khugepaged scan logic" (Vernon Yang) Improve khugepaged scan logic and reduce CPU consumption by prioritizing scanning tasks that access memory frequently - "Make KHO Stateless" (Jason Miu) Simplify Kexec Handover by transitioning KHO from an xarray-based metadata tracking system with serialization to a radix tree data structure that can be passed directly to the next kernel - "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas Ballasi and Steven Rostedt) Enhance vmscan's tracepointing - "mm: arch/shstk: Common shadow stack mapping helper and VM_NOHUGEPAGE" (Catalin Marinas) Cleanup for the shadow stack code: remove per-arch code in favour of a generic implementation - "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin) Fix a WARN() which can be emitted the KHO restores a vmalloc area - "mm: Remove stray references to pagevec" (Tal Zussman) Several cleanups, mainly udpating references to "struct pagevec", which became folio_batch three years ago - "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl Shutsemau) Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail pages encode their relationship to the head page - "mm/damon/core: improve DAMOS quota efficiency for core layer filters" (SeongJae Park) Improve two problematic behaviors of DAMOS that makes it less efficient when core layer filters are used - "mm/damon: strictly respect min_nr_regions" (SeongJae Park) Improve DAMON usability by extending the treatment of the min_nr_regions user-settable parameter - "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka) The proper fix for a previously hotfixed SMP=n issue. Code simplifications and cleanups ensued - "mm: cleanups around unmapping / zapping" (David Hildenbrand) A bunch of cleanups around unmapping and zapping. Mostly simplifications, code movements, documentation and renaming of zapping functions - "support batched checking of the young flag for MGLRU" (Baolin Wang) Batched checking of the young flag for MGLRU. It's part cleanups; one benchmark shows large performance benefits for arm64 - "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner) memcg cleanup and robustness improvements - "Allow order zero pages in page reporting" (Yuvraj Sakshith) Enhance free page reporting - it is presently and undesirably order-0 pages when reporting free memory. - "mm: vma flag tweaks" (Lorenzo Stoakes) Cleanup work following from the recent conversion of the VMA flags to a bitmap - "mm/damon: add optional debugging-purpose sanity checks" (SeongJae Park) Add some more developer-facing debug checks into DAMON core - "mm/damon: test and document power-of-2 min_region_sz requirement" (SeongJae Park) An additional DAMON kunit test and makes some adjustments to the addr_unit parameter handling - "mm/damon/core: make passed_sample_intervals comparisons overflow-safe" (SeongJae Park) Fix a hard-to-hit time overflow issue in DAMON core - "mm/damon: improve/fixup/update ratio calculation, test and documentation" (SeongJae Park) A batch of misc/minor improvements and fixups for DAMON - "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David Hildenbrand) Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code movement was required. - "zram: recompression cleanups and tweaks" (Sergey Senozhatsky) A somewhat random mix of fixups, recompression cleanups and improvements in the zram code - "mm/damon: support multiple goal-based quota tuning algorithms" (SeongJae Park) Extend DAMOS quotas goal auto-tuning to support multiple tuning algorithms that users can select - "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao) Fix the khugpaged sysfs handling so we no longer spam the logs with reams of junk when starting/stopping khugepaged - "mm: improve map count checks" (Lorenzo Stoakes) Provide some cleanups and slight fixes in the mremap, mmap and vma code - "mm/damon: support addr_unit on default monitoring targets for modules" (SeongJae Park) Extend the use of DAMON core's addr_unit tunable - "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache) Cleanups to khugepaged and is a base for Nico's planned khugepaged mTHP support - "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand) Code movement and cleanups in the memhotplug and sparsemem code - "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup CONFIG_MIGRATION" (David Hildenbrand) Rationalize some memhotplug Kconfig support - "change young flag check functions to return bool" (Baolin Wang) Cleanups to change all young flag check functions to return bool - "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh Law and SeongJae Park) Fix a few potential DAMON bugs - "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo Stoakes) Convert a lot of the existing use of the legacy vm_flags_t data type to the new vma_flags_t type which replaces it. Mainly in the vma code. - "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes) Expand the mmap_prepare functionality, which is intended to replace the deprecated f_op->mmap hook which has been the source of bugs and security issues for some time. Cleanups, documentation, extension of mmap_prepare into filesystem drivers - "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes) Simplify and clean up zap_huge_pmd(). Additional cleanups around vm_normal_folio_pmd() and the softleaf functionality are performed. * tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm: fix deferred split queue races during migration mm/khugepaged: fix issue with tracking lock mm/huge_memory: add and use has_deposited_pgtable() mm/huge_memory: add and use normal_or_softleaf_folio_pmd() mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio() mm/huge_memory: separate out the folio part of zap_huge_pmd() mm/huge_memory: use mm instead of tlb->mm mm/huge_memory: remove unnecessary sanity checks mm/huge_memory: deduplicate zap deposited table call mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE() mm/huge_memory: add a common exit path to zap_huge_pmd() mm/huge_memory: handle buggy PMD entry in zap_huge_pmd() mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc mm/huge: avoid big else branch in zap_huge_pmd() mm/huge_memory: simplify vma_is_specal_huge() mm: on remap assert that input range within the proposed VMA mm: add mmap_action_map_kernel_pages[_full]() uio: replace deprecated mmap hook with mmap_prepare in uio_info drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare mm: allow handling of stacked mmap_prepare hooks in more drivers ... |
||
|
Linus Torvalds
|
d568788baa |
Merge tag 'hardening-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening updates from Kees Cook: - randomize_kstack: Improve implementation across arches (Ryan Roberts) - lkdtm/fortify: Drop unneeded FORTIFY_STR_OBJECT test - refcount: Remove unused __signed_wrap function annotations * tag 'hardening-v7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: lkdtm/fortify: Drop unneeded FORTIFY_STR_OBJECT test refcount: Remove unused __signed_wrap function annotations randomize_kstack: Unify random source across arches randomize_kstack: Maintain kstack_offset per task |
||
 Paolo Bonzini
|
6b80203187 |
Merge tag 'kvm-s390-next-7.1-1' of https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD
- ESA nesting support - 4k memslots - LPSW/E fix |
||
  Niklas SchnelleandVasily Gorbik
|
e4f9ab031d |
PCI: s390: Expose the UID as an arch specific PCI slot attribute
On s390, an individual PCI function can generally be identified by two
identifiers, the FID and the UID. Which identifier is used depends on
the scope and the platform configuration.
The first identifier, the FID, is always available and identifies a PCI
device uniquely within a machine. The FID may be virtualized by
hypervisors, but on the LPAR level, the machine scope makes it
impossible to create the same configuration based on FIDs on two
different LPARs of the same machine, and difficult to reuse across
machines.
Such matching LPAR configurations are useful, though, allowing
standardized setups and booting a Linux installation on different LPARs.
To this end the UID, or user-defined identifier, was introduced. While
it is only guaranteed to be unique within an LPAR and only if indicated
by firmware, it allows users to replicate PCI device setups.
On s390, which uses a machine hypervisor, a per PCI function hotplug
model is used. The shortcoming with the UID then is, that it is not
visible to the user without first attaching the PCI function and
accessing the "uid" device attribute. The FID, on the other hand, is
used as the slot name and is thus known even with the PCI function in
standby.
Remedy this shortcoming by providing the UID as an attribute on the slot
allowing the user to identify a PCI function based on the UID without
having to first attach it. Do this via a macro mechanism analogous to
what was introduced by commit
|
||
  Lorenzo Stoakes (Oracle)andAndrew Morton
|
3a6455d56b |
mm: convert do_brk_flags() to use vma_flags_t
In order to be able to do this, we need to change VM_DATA_DEFAULT_FLAGS and friends and update the architecture-specific definitions also. We then have to update some KSM logic to handle VMA flags, and introduce VMA_STACK_FLAGS to define the vma_flags_t equivalent of VM_STACK_FLAGS. We also introduce two helper functions for use during the time we are converting legacy flags to vma_flags_t values - vma_flags_to_legacy() and legacy_to_vma_flags(). This enables us to iteratively make changes to break these changes up into separate parts. We use these explicitly here to keep VM_STACK_FLAGS around for certain users which need to maintain the legacy vm_flags_t values for the time being. We are no longer able to rely on the simple VM_xxx being set to zero if the feature is not enabled, so in the case of VM_DROPPABLE we introduce VMA_DROPPABLE as the vma_flags_t equivalent, which is set to EMPTY_VMA_FLAGS if the droppable flag is not available. While we're here, we make the description of do_brk_flags() into a kdoc comment, as it almost was already. We use vma_flags_to_legacy() to not need to update the vm_get_page_prot() logic as this time. Note that in create_init_stack_vma() we have to replace the BUILD_BUG_ON() with a VM_WARN_ON_ONCE() as the tested values are no longer build time available. We also update mprotect_fixup() to use VMA flags where possible, though we have to live with a little duplication between vm_flags_t and vma_flags_t values for the time being until further conversions are made. While we're here, update VM_SPECIAL to be defined in terms of VMA_SPECIAL_FLAGS now we have vma_flags_to_legacy(). Finally, we update the VMA tests to reflect these changes. Link: https://lkml.kernel.org/r/d02e3e45d9a33d7904b149f5604904089fd640ae.1774034900.git.ljs@kernel.org Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> [SELinux] Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Kees Cook <kees@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Ondrej Mosnacek <omosnace@redhat.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@armlinux.org.uk> Cc: Stephen Smalley <stephen.smalley.work@gmail.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Cc: xu xin <xu.xin16@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
 Baolin WangandAndrew Morton
|
2d46a39747 |
mm: change to return bool for pmdp_clear_flush_young()
The pmdp_clear_flush_young() is used to clear the young flag and flush the TLB, returning whether the young flag was set for this PMD entry. Change the return type to bool to make the intention clearer. Link: https://lkml.kernel.org/r/a668b9a974c0d675e7a41f6973bcbe3336e8b373.1774075004.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Baolin WangandAndrew Morton
|
42e26354c4 |
mm: change to return bool for pmdp_test_and_clear_young()
Callers use pmdp_test_and_clear_young() to clear the young flag and check whether it was set for this PMD entry. Change the return type to bool to make the intention clearer. Link: https://lkml.kernel.org/r/f1d31307a13365d3d0fed5809727dcc2dd59631b.1774075004.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Baolin WangandAndrew Morton
|
06c4dfa3ce |
mm: change to return bool for ptep_clear_flush_young()/clear_flush_young_ptes()
The ptep_clear_flush_young() and clear_flush_young_ptes() are used to clear the young flag and flush the TLB, returning whether the young flag was set. Change the return type to bool to make the intention clearer. Link: https://lkml.kernel.org/r/24af5144b96103631594501f77d4525f2475c1be.1774075004.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Baolin WangandAndrew Morton
|
a62ca3f40f |
mm: change to return bool for ptep_test_and_clear_young()
Patch series "change young flag check functions to return bool", v2. This is a cleanup patchset to change all young flag check functions to return bool, as discussed with David in the previous thread[1]. Since callers only care about whether the young flag was set, returning bool makes the intention clearer. No functional changes intended. This patch (of 6): Callers use ptep_test_and_clear_young() to clear the young flag and check whether it was set. Change the return type to bool to make the intention clearer. Link: https://lkml.kernel.org/r/cover.1774075004.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/57e70efa9703d43959aa645246ea3cbdba14fa17.1774075004.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
 Christoph HellwigandAndrew Morton
|
e20043b476 |
xor: make xor.ko self-contained in lib/raid/
Move the asm/xor.h headers to lib/raid/xor/$(SRCARCH)/xor_arch.h and include/linux/raid/xor_impl.h to lib/raid/xor/xor_impl.h so that the xor.ko module implementation is self-contained in lib/raid/. As this remove the asm-generic mechanism a new kconfig symbol is added to indicate that a architecture-specific implementations exists, and xor_arch.h should be included. Link: https://lkml.kernel.org/r/20260327061704.3707577-22-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Eric Biggers <ebiggers@kernel.org> Tested-by: Eric Biggers <ebiggers@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason A. Donenfeld <jason@zx2c4.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Magnus Lindholm <linmag7@gmail.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@armlinux.org.uk> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Ted Ts'o <tytso@mit.edu> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Christoph HellwigandAndrew Morton
|
35ebc4de10 |
xor: remove macro abuse for XOR implementation registrations
Drop the pretty confusing historic XOR_TRY_TEMPLATES and XOR_SELECT_TEMPLATE, and instead let the architectures provide a arch_xor_init that calls either xor_register to register candidates or xor_force to force a specific implementation. Link: https://lkml.kernel.org/r/20260327061704.3707577-10-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Eric Biggers <ebiggers@kernel.org> Tested-by: Eric Biggers <ebiggers@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: David Sterba <dsterba@suse.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason A. Donenfeld <jason@zx2c4.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Li Nan <linan122@huawei.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Magnus Lindholm <linmag7@gmail.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@armlinux.org.uk> Cc: Song Liu <song@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Ted Ts'o <tytso@mit.edu> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
  Eric FarmanandJanosch Frank
|
c0dcada088 |
KVM: s390: vsie: Accommodate ESA prefix pages
The prefix page address occupies a different number of bits for z/Architecture versus ESA mode. Adjust the definition to cover both, and permit an ESA mode address within the nested codepath. Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com> Signed-off-by: Janosch Frank <frankja@linux.ibm.com> |
||
|
Eric FarmanandJanosch Frank
|
b0ad874d98 |
KVM: s390: vsie: Allow non-zarch guests
Linux/KVM runs in z/Architecture-only mode. Although z/Architecture is built upon a long history of hardware refinements, any other CPU mode is not permitted. Allow a userspace to explicitly enable the use of ESA mode for nested guests, otherwise usage will be rejected. Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com> Signed-off-by: Janosch Frank <frankja@linux.ibm.com> |
||
|
Linus Torvalds
|
e522b75c44 |
Merge tag 's390-7.0-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Vasily Gorbik: - Add array_index_nospec() to syscall dispatch table lookup to prevent limited speculative out-of-bounds access with user-controlled syscall number - Mark array_index_mask_nospec() __always_inline since GCC may emit an out-of-line call instead of the inline data dependency sequence the mitigation relies on - Clear r12 on kernel entry to prevent potential speculative use of user value in system_call, ext/io/mcck interrupt handlers * tag 's390-7.0-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/entry: Scrub r12 register on kernel entry s390/syscalls: Add spectre boundary for syscall dispatch table s390/barrier: Make array_index_mask_nospec() __always_inline |
||
|
Vasily Gorbik
|
c5c0a268b3 |
s390/barrier: Make array_index_mask_nospec() __always_inline
Mark array_index_mask_nospec() as __always_inline to guarantee the
mitigation is emitted inline regardless of compiler inlining decisions.
Fixes:
|
||
  Ryan RobertsandKees Cook
|
a96ef5848c |
randomize_kstack: Unify random source across arches
Previously different architectures were using random sources of
differing strength and cost to decide the random kstack offset. A number
of architectures (loongarch, powerpc, s390, x86) were using their
timestamp counter, at whatever the frequency happened to be. Other
arches (arm64, riscv) were using entropy from the crng via
get_random_u16().
There have been concerns that in some cases the timestamp counters may
be too weak, because they can be easily guessed or influenced by user
space. And get_random_u16() has been shown to be too costly for the
level of protection kstack offset randomization provides.
So let's use a common, architecture-agnostic source of entropy; a
per-cpu prng, seeded at boot-time from the crng. This has a few
benefits:
- We can remove choose_random_kstack_offset(); That was only there to
try to make the timestamp counter value a bit harder to influence
from user space [*].
- The architecture code is simplified. All it has to do now is call
add_random_kstack_offset() in the syscall path.
- The strength of the randomness can be reasoned about independently
of the architecture.
- Arches previously using get_random_u16() now have much faster
syscall paths, see below results.
[*] Additionally, this gets rid of some redundant work on s390 and x86.
Before this patch, those architectures called
choose_random_kstack_offset() under arch_exit_to_user_mode_prepare(),
which is also called for exception returns to userspace which were *not*
syscalls (e.g. regular interrupts). Getting rid of
choose_random_kstack_offset() avoids a small amount of redundant work
for the non-syscall cases.
In some configurations, add_random_kstack_offset() will now call
instrumentable code, so for a couple of arches, I have moved the call a
bit later to the first point where instrumentation is allowed. This
doesn't impact the efficacy of the mechanism.
There have been some claims that a prng may be less strong than the
timestamp counter if not regularly reseeded. But the prng has a period
of about 2^113. So as long as the prng state remains secret, it should
not be possible to guess. If the prng state can be accessed, we have
bigger problems.
Additionally, we are only consuming 6 bits to randomize the stack, so
there are only 64 possible random offsets. I assert that it would be
trivial for an attacker to brute force by repeating their attack and
waiting for the random stack offset to be the desired one. The prng
approach seems entirely proportional to this level of protection.
Performance data are provided below. The baseline is v6.18 with rndstack
on for each respective arch. (I)/(R) indicate statistically significant
improvement/regression. arm64 platform is AWS Graviton3 (m7g.metal).
x86_64 platform is AWS Sapphire Rapids (m7i.24xlarge):
+-----------------+--------------+---------------+---------------+
| Benchmark | Result Class | per-cpu-prng | per-cpu-prng |
| | | arm64 (metal) | x86_64 (VM) |
+=================+==============+===============+===============+
| syscall/getpid | mean (ns) | (I) -9.50% | (I) -17.65% |
| | p99 (ns) | (I) -59.24% | (I) -24.41% |
| | p99.9 (ns) | (I) -59.52% | (I) -28.52% |
+-----------------+--------------+---------------+---------------+
| syscall/getppid | mean (ns) | (I) -9.52% | (I) -19.24% |
| | p99 (ns) | (I) -59.25% | (I) -25.03% |
| | p99.9 (ns) | (I) -59.50% | (I) -28.17% |
+-----------------+--------------+---------------+---------------+
| syscall/invalid | mean (ns) | (I) -10.31% | (I) -18.56% |
| | p99 (ns) | (I) -60.79% | (I) -20.06% |
| | p99.9 (ns) | (I) -61.04% | (I) -25.04% |
+-----------------+--------------+---------------+---------------+
I tested an earlier version of this change on x86 bare metal and it
showed a smaller but still significant improvement. The bare metal
system wasn't available this time around so testing was done in a VM
instance. I'm guessing the cost of rdtsc is higher for VMs.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://patch.msgid.link/20260303150840.3789438-3-ryan.roberts@arm.com
Signed-off-by: Kees Cook <kees@kernel.org>
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 Heiko CarstensandVasily Gorbik
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fa8be59ce2 |
s390/percpu: Provide arch_raw_cpu_ptr()
Provide an s390 specific arch_raw_cpu_ptr() implementation which avoids the detour over get_lowcore() to get the lowcore pointer. The inline assembly is implemented with an alternative so that relocated lowcore (percpu offset is at a different address) is handled correctly. This turns code like this 102f78: a7 39 00 00 lghi %r3,0 102f7c: e3 20 33 b8 00 08 ag %r2,952(%r3) which adds the percpu offset to register r2 into a single instruction 102f7c: e3 20 33 b8 00 08 ag %r2,952(%r0) and also avoids the need of a base register, thus reducing register pressure. With defconfig bloat-o-meter -t provides this result: add/remove: 12/26 grow/shrink: 183/3391 up/down: 14880/-41950 (-27070) Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> |
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Paolo Bonzini
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12fd965871 |
Merge tag 'kvm-s390-master-7.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD
KVM: s390: Fixes for 7.0 - fix deadlock in new memory management - handle kernel faults on donated memory properly - fix bounds checking for irq routing + selftest - fix invalid machine checks + logging |