March 2025 - Linux-kselftest-mirror

[PATCH v8 00/14] iommufd: Add vIOMMU infrastructure (Part-3: vEVENTQ)

by Nicolin Chen

As the vIOMMU infrastructure series part-3, this introduces a new vEVENTQ object. The existing FAULT object provides a nice notification pathway to the user space with a queue already, so let vEVENTQ reuse that. Mimicing the HWPT structure, add a common EVENTQ structure to support its derivatives: IOMMUFD_OBJ_FAULT (existing) and IOMMUFD_OBJ_VEVENTQ (new). An IOMMUFD_CMD_VEVENTQ_ALLOC is introduced to allocate vEVENTQ object for vIOMMUs. One vIOMMU can have multiple vEVENTQs in different types but can not support multiple vEVENTQs in the same type. The forwarding part is fairly simple but might need to replace a physical device ID with a virtual device ID in a driver-level event data structure. So, this also adds some helpers for drivers to use. As usual, this series comes with the selftest coverage for this new ioctl and with a real world use case in the ARM SMMUv3 driver. This is on Github: https://github.com/nicolinc/iommufd/commits/iommufd_veventq-v8 Paring QEMU branch for testing: https://github.com/nicolinc/qemu/commits/wip/for_iommufd_veventq-v8 Changelog v8 * Add Reviewed-by from Jason and Pranjal * Fix errno returned in arm_smmu_handle_event() * Validate domain->type outside of arm_smmu_attach_prepare_vmaster() * Drop unnecessary vmaster comparison in arm_smmu_attach_commit_vmaster() v7 https://lore.kernel.org/all/cover.1740238876.git.nicolinc@nvidia.com/ * Rebase on Jason's for-next tree for latest fault.c * Add Reviewed-by * Update commit logs * Add __reserved field sanity * Skip kfree() on the static header * Replace "bool on_list" with list_is_last() * Use u32 for flags in iommufd_vevent_header * Drop casting in iommufd_viommu_get_vdev_id() * Update the bounding logic to veventq->sequence * Add missing cpu_to_le64() around STRTAB_STE_1_MEV * Reuse veventq->common.lock to fence sequence and num_events * Rename overflow to lost_events and log it in upon kmalloc failure * Correct the error handling part in iommufd_veventq_deliver_fetch() * Add an arm_smmu_clear_vmaster() to simplify identity/blocked domain attach ops * Add additional four event records to forward to user space VM, and update the uAPI doc * Reuse the existing smmu->streams_mutex lock to fence master->vmaster pointer, instead of adding a new rwsem v6 https://lore.kernel.org/all/cover.1737754129.git.nicolinc@nvidia.com/ * Drop supports_veventq viommu op * Split bug/cosmetics fixes out of the series * Drop the blocking mutex around copy_to_user() * Add veventq_depth in uAPI to limit vEVENTQ size * Revise the documentation for a clear description * Fix sparse warnings in arm_vmaster_report_event() * Rework iommufd_viommu_get_vdev_id() to return -ENOENT v.s. 0 * Allow Abort/Bypass STEs to allocate vEVENTQ and set STE.MEV for DoS mitigations v5 https://lore.kernel.org/all/cover.1736237481.git.nicolinc@nvidia.com/ * Add Reviewed-by from Baolu * Reorder the OBJ list as well * Fix alphabetical order after renaming in v4 * Add supports_veventq viommu op for vEVENTQ type validation v4 https://lore.kernel.org/all/cover.1735933254.git.nicolinc@nvidia.com/ * Rename "vIRQ" to "vEVENTQ" * Use flexible array in struct iommufd_vevent * Add the new ioctl command to union ucmd_buffer * Fix the alphabetical order in union ucmd_buffer too * Rename _TYPE_NONE to _TYPE_DEFAULT aligning with vIOMMU naming v3 https://lore.kernel.org/all/cover.1734477608.git.nicolinc@nvidia.com/ * Rebase on Will's for-joerg/arm-smmu/updates for arm_smmu_event series * Add "Reviewed-by" lines from Kevin * Fix typos in comments, kdocs, and jump tags * Add a patch to sort struct iommufd_ioctl_op * Update iommufd's userpsace-api documentation * Update uAPI kdoc to quote SMMUv3 offical spec * Drop the unused workqueue in struct iommufd_virq * Drop might_sleep() in iommufd_viommu_report_irq() helper * Add missing "break" in iommufd_viommu_get_vdev_id() helper * Shrink the scope of the vmaster's read lock in SMMUv3 driver * Pass in two arguments to iommufd_eventq_virq_handler() helper * Move "!ops || !ops->read" validation into iommufd_eventq_init() * Move "fault->ictx = ictx" closer to iommufd_ctx_get(fault->ictx) * Update commit message for arm_smmu_attach_prepare/commit_vmaster() * Keep "iommufd_fault" as-is and rename "iommufd_eventq_virq" to just "iommufd_virq" v2 https://lore.kernel.org/all/cover.1733263737.git.nicolinc@nvidia.com/ * Rebase on v6.13-rc1 * Add IOPF and vIRQ in iommufd.rst (userspace-api) * Add a proper locking in iommufd_event_virq_destroy * Add iommufd_event_virq_abort with a lockdep_assert_held * Rename "EVENT_*" to "EVENTQ_*" to describe the objects better * Reorganize flows in iommufd_eventq_virq_alloc for abort() to work * Adde struct arm_smmu_vmaster to store vSID upon attaching to a nested domain, calling a newly added iommufd_viommu_get_vdev_id helper * Adde an arm_vmaster_report_event helper in arm-smmu-v3-iommufd file to simplify the routine in arm_smmu_handle_evt() of the main driver v1 https://lore.kernel.org/all/cover.1724777091.git.nicolinc@nvidia.com/ Thanks! Nicolin Nicolin Chen (14): iommufd/fault: Move two fault functions out of the header iommufd/fault: Add an iommufd_fault_init() helper iommufd: Abstract an iommufd_eventq from iommufd_fault iommufd: Rename fault.c to eventq.c iommufd: Add IOMMUFD_OBJ_VEVENTQ and IOMMUFD_CMD_VEVENTQ_ALLOC iommufd/viommu: Add iommufd_viommu_get_vdev_id helper iommufd/viommu: Add iommufd_viommu_report_event helper iommufd/selftest: Require vdev_id when attaching to a nested domain iommufd/selftest: Add IOMMU_TEST_OP_TRIGGER_VEVENT for vEVENTQ coverage iommufd/selftest: Add IOMMU_VEVENTQ_ALLOC test coverage Documentation: userspace-api: iommufd: Update FAULT and VEVENTQ iommu/arm-smmu-v3: Introduce struct arm_smmu_vmaster iommu/arm-smmu-v3: Report events that belong to devices attached to vIOMMU iommu/arm-smmu-v3: Set MEV bit in nested STE for DoS mitigations drivers/iommu/iommufd/Makefile | 2 +- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 36 ++ drivers/iommu/iommufd/iommufd_private.h | 135 +++- drivers/iommu/iommufd/iommufd_test.h | 10 + include/linux/iommufd.h | 23 + include/uapi/linux/iommufd.h | 105 +++ tools/testing/selftests/iommu/iommufd_utils.h | 115 ++++ .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 64 ++ drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 82 ++- drivers/iommu/iommufd/driver.c | 72 +++ drivers/iommu/iommufd/eventq.c | 597 ++++++++++++++++++ drivers/iommu/iommufd/fault.c | 342 ---------- drivers/iommu/iommufd/hw_pagetable.c | 6 +- drivers/iommu/iommufd/main.c | 7 + drivers/iommu/iommufd/selftest.c | 54 ++ drivers/iommu/iommufd/viommu.c | 2 + tools/testing/selftests/iommu/iommufd.c | 36 ++ .../selftests/iommu/iommufd_fail_nth.c | 7 + Documentation/userspace-api/iommufd.rst | 17 + 19 files changed, 1304 insertions(+), 408 deletions(-) create mode 100644 drivers/iommu/iommufd/eventq.c delete mode 100644 drivers/iommu/iommufd/fault.c base-commit: 598749522d4254afb33b8a6c1bea614a95896868 -- 2.43.0

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[PATCH v12 00/28] riscv control-flow integrity for usermode

by Deepak Gupta

Basics and overview =================== Software with larger attack surfaces (e.g. network facing apps like databases, browsers or apps relying on browser runtimes) suffer from memory corruption issues which can be utilized by attackers to bend control flow of the program to eventually gain control (by making their payload executable). Attackers are able to perform such attacks by leveraging call-sites which rely on indirect calls or return sites which rely on obtaining return address from stack memory. To mitigate such attacks, risc-v extension zicfilp enforces that all indirect calls must land on a landing pad instruction `lpad` else cpu will raise software check exception (a new cpu exception cause code on riscv). Similarly for return flow, risc-v extension zicfiss extends architecture with - `sspush` instruction to push return address on a shadow stack - `sspopchk` instruction to pop return address from shadow stack and compare with input operand (i.e. return address on stack) - `sspopchk` to raise software check exception if comparision above was a mismatch - Protection mechanism using which shadow stack is not writeable via regular store instructions More information an details can be found at extensions github repo [1]. Equivalent to landing pad (zicfilp) on x86 is `ENDBRANCH` instruction in Intel CET [3] and branch target identification (BTI) [4] on arm. Similarly x86's Intel CET has shadow stack [5] and arm64 has guarded control stack (GCS) [6] which are very similar to risc-v's zicfiss shadow stack. x86 and arm64 support for user mode shadow stack is already in mainline. Kernel awareness for user control flow integrity ================================================ This series picks up Samuel Holland's envcfg changes [2] as well. So if those are being applied independently, they should be removed from this series. Enabling: In order to maintain compatibility and not break anything in user mode, kernel doesn't enable control flow integrity cpu extensions on binary by default. Instead exposes a prctl interface to enable, disable and lock the shadow stack or landing pad feature for a task. This allows userspace (loader) to enumerate if all objects in its address space are compiled with shadow stack and landing pad support and accordingly enable the feature. Additionally if a subsequent `dlopen` happens on a library, user mode can take a decision again to disable the feature (if incoming library is not compiled with support) OR terminate the task (if user mode policy is strict to have all objects in address space to be compiled with control flow integirty cpu feature). prctl to enable shadow stack results in allocating shadow stack from virtual memory and activating for user address space. x86 and arm64 are also following same direction due to similar reason(s). clone/fork: On clone and fork, cfi state for task is inherited by child. Shadow stack is part of virtual memory and is a writeable memory from kernel perspective (writeable via a restricted set of instructions aka shadow stack instructions) Thus kernel changes ensure that this memory is converted into read-only when fork/clone happens and COWed when fault is taken due to sspush, sspopchk or ssamoswap. In case `CLONE_VM` is specified and shadow stack is to be enabled, kernel will automatically allocate a shadow stack for that clone call. map_shadow_stack: x86 introduced `map_shadow_stack` system call to allow user space to explicitly map shadow stack memory in its address space. It is useful to allocate shadow for different contexts managed by a single thread (green threads or contexts) risc-v implements this system call as well. signal management: If shadow stack is enabled for a task, kernel performs an asynchronous control flow diversion to deliver the signal and eventually expects userspace to issue sigreturn so that original execution can be resumed. Even though resume context is prepared by kernel, it is in user space memory and is subject to memory corruption and corruption bugs can be utilized by attacker in this race window to perform arbitrary sigreturn and eventually bypass cfi mechanism. Another issue is how to ensure that cfi related state on sigcontext area is not trampled by legacy apps or apps compiled with old kernel headers. In order to mitigate control-flow hijacting, kernel prepares a token and place it on shadow stack before signal delivery and places address of token in sigcontext structure. During sigreturn, kernel obtains address of token from sigcontext struture, reads token from shadow stack and validates it and only then allow sigreturn to succeed. Compatiblity issue is solved by adopting dynamic sigcontext management introduced for vector extension. This series re-factor the code little bit to allow future sigcontext management easy (as proposed by Andy Chiu from SiFive) config and compilation: Introduce a new risc-v config option `CONFIG_RISCV_USER_CFI`. Selecting this config option picks the kernel support for user control flow integrity. This optin is presented only if toolchain has shadow stack and landing pad support. And is on purpose guarded by toolchain support. Reason being that eventually vDSO also needs to be compiled in with shadow stack and landing pad support. vDSO compile patches are not included as of now because landing pad labeling scheme is yet to settle for usermode runtime. To get more information on kernel interactions with respect to zicfilp and zicfiss, patch series adds documentation for `zicfilp` and `zicfiss` in following: Documentation/arch/riscv/zicfiss.rst Documentation/arch/riscv/zicfilp.rst How to test this series ======================= Toolchain --------- $ git clone git@github.com:sifive/riscv-gnu-toolchain.git -b cfi-dev $ riscv-gnu-toolchain/configure --prefix=<path-to-where-to-build> --with-arch=rv64gc_zicfilp_zicfiss --enable-linux --disable-gdb --with-extra-multilib-test="rv64gc_zicfilp_zicfiss-lp64d:-static" $ make -j$(nproc) Qemu ---- Get the lastest qemu $ cd qemu $ mkdir build $ cd build $ ../configure --target-list=riscv64-softmmu $ make -j$(nproc) Opensbi ------- $ git clone git@github.com:deepak0414/opensbi.git -b v6_cfi_spec_split_opensbi $ make CROSS_COMPILE=<your riscv toolchain> -j$(nproc) PLATFORM=generic Linux ----- Running defconfig is fine. CFI is enabled by default if the toolchain supports it. $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) defconfig $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) In case you're building your own rootfs using toolchain, please make sure you pick following patch to ensure that vDSO compiled with lpad and shadow stack. "arch/riscv: compile vdso with landing pad" Branch where above patch can be picked https://github.com/deepak0414/linux-riscv-cfi/tree/vdso_user_cfi_v6.12-rc1 Running ------- Modify your qemu command to have: -bios <path-to-cfi-opensbi>/build/platform/generic/firmware/fw_dynamic.bin -cpu rv64,zicfilp=true,zicfiss=true,zimop=true,zcmop=true vDSO related Opens (in the flux) ================================= I am listing these opens for laying out plan and what to expect in future patch sets. And of course for the sake of discussion. Shadow stack and landing pad enabling in vDSO ---------------------------------------------- vDSO must have shadow stack and landing pad support compiled in for task to have shadow stack and landing pad support. This patch series doesn't enable that (yet). Enabling shadow stack support in vDSO should be straight forward (intend to do that in next versions of patch set). Enabling landing pad support in vDSO requires some collaboration with toolchain folks to follow a single label scheme for all object binaries. This is necessary to ensure that all indirect call-sites are setting correct label and target landing pads are decorated with same label scheme. How many vDSOs --------------- Shadow stack instructions are carved out of zimop (may be operations) and if CPU doesn't implement zimop, they're illegal instructions. Kernel could be running on a CPU which may or may not implement zimop. And thus kernel will have to carry 2 different vDSOs and expose the appropriate one depending on whether CPU implements zimop or not. References ========== [1] - https://github.com/riscv/riscv-cfi [2] - https://lore.kernel.org/all/20240814081126.956287-1-samuel.holland@sifive.c… [3] - https://lwn.net/Articles/889475/ [4] - https://developer.arm.com/documentation/109576/0100/Branch-Target-Identific… [5] - https://www.intel.com/content/dam/develop/external/us/en/documents/catc17-i… [6] - https://lwn.net/Articles/940403/ --- changelog --------- v12: - It seems like I had accidently squashed arch agnostic indirect branch tracking prctl and riscv implementation of those prctls. Split them again. - set_shstk_status/set_indir_lp_status perform CSR writes only when CPU support is available. As suggested by Zong Li. - Some minor clean up in kselftests as suggested by Zong Li. v11: - patch "arch/riscv: compile vdso with landing pad" was unconditionally selecting `_zicfilp` for vDSO compile. fixed that. Changed `lpad 1` to to `lpad 0`. v10: - dropped "mm: helper `is_shadow_stack_vma` to check shadow stack vma". This patch is not that interesting to this patch series for risc-v. There are instances in arch directories where VM_SHADOW_STACK flag is anyways used. Dropping this patch to expedite merging in riscv tree. - Took suggestions from `Clement` on "riscv: zicfiss / zicfilp enumeration" to validate presence of cfi based on config. - Added a patch for vDSO to have `lpad 0`. I had omitted this earlier to make sure we add single vdso object with cfi enabled. But a vdso object with scheme of zero labeled landing pad is least common denominator and should work with all objects of zero labeled as well as function-signature labeled objects. v9: - rebased on master (39a803b754d5 fix braino in "9p: fix ->rename_sem exclusion") - dropped "mm: Introduce ARCH_HAS_USER_SHADOW_STACK" (master has it from arm64/gcs) - dropped "prctl: arch-agnostic prctl for shadow stack" (master has it from arm64/gcs) v8: - rebased on palmer/for-next - dropped samuel holland's `envcfg` context switch patches. they are in parlmer/for-next v7: - Removed "riscv/Kconfig: enable HAVE_EXIT_THREAD for riscv" Instead using `deactivate_mm` flow to clean up. see here for more context https://lore.kernel.org/all/20230908203655.543765-1-rick.p.edgecombe@intel.… - Changed the header include in `kselftest`. Hopefully this fixes compile issue faced by Zong Li at SiFive. - Cleaned up an orphaned change to `mm/mmap.c` in below patch "riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE" - Lock interfaces for shadow stack and indirect branch tracking expect arg == 0 Any future evolution of this interface should accordingly define how arg should be setup. - `mm/map.c` has an instance of using `VM_SHADOW_STACK`. Fixed it to use helper `is_shadow_stack_vma`. - Link to v6: https://lore.kernel.org/r/20241008-v5_user_cfi_series-v6-0-60d9fe073f37@riv… v6: - Picked up Samuel Holland's changes as is with `envcfg` placed in `thread` instead of `thread_info` - fixed unaligned newline escapes in kselftest - cleaned up messages in kselftest and included test output in commit message - fixed a bug in clone path reported by Zong Li - fixed a build issue if CONFIG_RISCV_ISA_V is not selected (this was introduced due to re-factoring signal context management code) v5: - rebased on v6.12-rc1 - Fixed schema related issues in device tree file - Fixed some of the documentation related issues in zicfilp/ss.rst (style issues and added index) - added `SHADOW_STACK_SET_MARKER` so that implementation can define base of shadow stack. - Fixed warnings on definitions added in usercfi.h when CONFIG_RISCV_USER_CFI is not selected. - Adopted context header based signal handling as proposed by Andy Chiu - Added support for enabling kernel mode access to shadow stack using FWFT (https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/src/ext-firmware…) - Link to v5: https://lore.kernel.org/r/20241001-v5_user_cfi_series-v1-0-3ba65b6e550f@riv… (Note: I had an issue in my workflow due to which version number wasn't picked up correctly while sending out patches) v4: - rebased on 6.11-rc6 - envcfg: Converged with Samuel Holland's patches for envcfg management on per- thread basis. - vma_is_shadow_stack is renamed to is_vma_shadow_stack - picked up Mark Brown's `ARCH_HAS_USER_SHADOW_STACK` patch - signal context: using extended context management to maintain compatibility. - fixed `-Wmissing-prototypes` compiler warnings for prctl functions - Documentation fixes and amending typos. - Link to v4: https://lore.kernel.org/all/20240912231650.3740732-1-debug@rivosinc.com/ v3: - envcfg logic to pick up base envcfg had a bug where `ENVCFG_CBZE` could have been picked on per task basis, even though CPU didn't implement it. Fixed in this series. - dt-bindings As suggested, split into separate commit. fixed the messaging that spec is in public review - arch_is_shadow_stack change arch_is_shadow_stack changed to vma_is_shadow_stack - hwprobe zicfiss / zicfilp if present will get enumerated in hwprobe - selftests As suggested, added object and binary filenames to .gitignore Selftest binary anyways need to be compiled with cfi enabled compiler which will make sure that landing pad and shadow stack are enabled. Thus removed separate enable/disable tests. Cleaned up tests a bit. - Link to v3: https://lore.kernel.org/lkml/20240403234054.2020347-1-debug@rivosinc.com/ v2: - Using config `CONFIG_RISCV_USER_CFI`, kernel support for riscv control flow integrity for user mode programs can be compiled in the kernel. - Enabling of control flow integrity for user programs is left to user runtime - This patch series introduces arch agnostic `prctls` to enable shadow stack and indirect branch tracking. And implements them on riscv. --- --- Changes in v12: - EDITME: describe what is new in this series revision. - EDITME: use bulletpoints and terse descriptions. - Link to v11: https://lore.kernel.org/r/20250310-v5_user_cfi_series-v11-0-86b36cbfb910@ri… Changes in v11: - EDITME: describe what is new in this series revision. - EDITME: use bulletpoints and terse descriptions. - Link to v10: https://lore.kernel.org/r/20250210-v5_user_cfi_series-v10-0-163dcfa31c60@ri… --- Andy Chiu (1): riscv: signal: abstract header saving for setup_sigcontext Clément Léger (1): riscv: Add Firmware Feature SBI extensions definitions Deepak Gupta (25): mm: VM_SHADOW_STACK definition for riscv dt-bindings: riscv: zicfilp and zicfiss in dt-bindings (extensions.yaml) riscv: zicfiss / zicfilp enumeration riscv: zicfiss / zicfilp extension csr and bit definitions riscv: usercfi state for task and save/restore of CSR_SSP on trap entry/exit riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE riscv mm: manufacture shadow stack pte riscv mmu: teach pte_mkwrite to manufacture shadow stack PTEs riscv mmu: write protect and shadow stack riscv/mm: Implement map_shadow_stack() syscall riscv/shstk: If needed allocate a new shadow stack on clone riscv: Implements arch agnostic shadow stack prctls prctl: arch-agnostic prctl for indirect branch tracking riscv: Implements arch agnostic indirect branch tracking prctls riscv/traps: Introduce software check exception riscv/signal: save and restore of shadow stack for signal riscv/kernel: update __show_regs to print shadow stack register riscv/ptrace: riscv cfi status and state via ptrace and in core files riscv/hwprobe: zicfilp / zicfiss enumeration in hwprobe riscv: enable kernel access to shadow stack memory via FWFT sbi call riscv: kernel command line option to opt out of user cfi riscv: create a config for shadow stack and landing pad instr support riscv: Documentation for landing pad / indirect branch tracking riscv: Documentation for shadow stack on riscv kselftest/riscv: kselftest for user mode cfi Jim Shu (1): arch/riscv: compile vdso with landing pad Documentation/arch/riscv/index.rst | 2 + Documentation/arch/riscv/zicfilp.rst | 115 +++++ Documentation/arch/riscv/zicfiss.rst | 176 +++++++ .../devicetree/bindings/riscv/extensions.yaml | 14 + arch/riscv/Kconfig | 20 + arch/riscv/Makefile | 5 +- arch/riscv/include/asm/asm-prototypes.h | 1 + arch/riscv/include/asm/assembler.h | 44 ++ arch/riscv/include/asm/cpufeature.h | 13 + arch/riscv/include/asm/csr.h | 16 + arch/riscv/include/asm/entry-common.h | 2 + arch/riscv/include/asm/hwcap.h | 2 + arch/riscv/include/asm/mman.h | 25 + arch/riscv/include/asm/mmu_context.h | 7 + arch/riscv/include/asm/pgtable.h | 30 +- arch/riscv/include/asm/processor.h | 2 + arch/riscv/include/asm/sbi.h | 26 + arch/riscv/include/asm/thread_info.h | 3 + arch/riscv/include/asm/usercfi.h | 89 ++++ arch/riscv/include/asm/vector.h | 3 + arch/riscv/include/uapi/asm/hwprobe.h | 2 + arch/riscv/include/uapi/asm/ptrace.h | 22 + arch/riscv/include/uapi/asm/sigcontext.h | 1 + arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/asm-offsets.c | 8 + arch/riscv/kernel/cpufeature.c | 13 + arch/riscv/kernel/entry.S | 31 +- arch/riscv/kernel/head.S | 12 + arch/riscv/kernel/process.c | 26 +- arch/riscv/kernel/ptrace.c | 83 ++++ arch/riscv/kernel/signal.c | 142 +++++- arch/riscv/kernel/sys_hwprobe.c | 2 + arch/riscv/kernel/sys_riscv.c | 10 + arch/riscv/kernel/traps.c | 43 ++ arch/riscv/kernel/usercfi.c | 530 +++++++++++++++++++++ arch/riscv/kernel/vdso/Makefile | 12 + arch/riscv/kernel/vdso/flush_icache.S | 4 + arch/riscv/kernel/vdso/getcpu.S | 4 + arch/riscv/kernel/vdso/rt_sigreturn.S | 4 + arch/riscv/kernel/vdso/sys_hwprobe.S | 4 + arch/riscv/mm/init.c | 2 +- arch/riscv/mm/pgtable.c | 17 + include/linux/cpu.h | 4 + include/linux/mm.h | 7 + include/uapi/linux/elf.h | 1 + include/uapi/linux/prctl.h | 27 ++ kernel/sys.c | 30 ++ tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/riscv/cfi/.gitignore | 3 + tools/testing/selftests/riscv/cfi/Makefile | 10 + tools/testing/selftests/riscv/cfi/cfi_rv_test.h | 82 ++++ tools/testing/selftests/riscv/cfi/riscv_cfi_test.c | 78 +++ tools/testing/selftests/riscv/cfi/shadowstack.c | 385 +++++++++++++++ tools/testing/selftests/riscv/cfi/shadowstack.h | 27 ++ 54 files changed, 2195 insertions(+), 29 deletions(-) --- base-commit: 39a803b754d5224a3522016b564113ee1e4091b2 change-id: 20240930-v5_user_cfi_series-3dc332f8f5b2 -- - debug

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[PATCH] selftests/x86/lam: fix memory leak and resource leak in lam.c

by Malaya Kumar Rout

Static Analyis for bench_htab_mem.c with cppcheck:error tools/testing/selftests/x86/lam.c:585:3: error: Resource leak: file_fd [resourceLeak] tools/testing/selftests/x86/lam.c:593:3: error: Resource leak: file_fd [resourceLeak] tools/testing/selftests/x86/lam.c:600:3: error: Memory leak: fi [memleak] tools/testing/selftests/x86/lam.c:1066:2: error: Resource leak: fd [resourceLeak] fix the issue by closing the file descriptors and releasing the allocated memory. Signed-off-by: Malaya Kumar Rout <malayarout91(a)gmail.com> --- tools/testing/selftests/x86/lam.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/x86/lam.c b/tools/testing/selftests/x86/lam.c index 4d4a76532dc9..0b43b83ad142 100644 --- a/tools/testing/selftests/x86/lam.c +++ b/tools/testing/selftests/x86/lam.c @@ -581,24 +581,28 @@ int do_uring(unsigned long lam) if (file_fd < 0) return 1; - if (fstat(file_fd, &st) < 0) + if (fstat(file_fd, &st) < 0) { + close(file_fd); return 1; - + } off_t file_sz = st.st_size; int blocks = (int)(file_sz + URING_BLOCK_SZ - 1) / URING_BLOCK_SZ; fi = malloc(sizeof(*fi) + sizeof(struct iovec) * blocks); - if (!fi) + if (!fi) { + close(file_fd); return 1; - + } fi->file_sz = file_sz; fi->file_fd = file_fd; ring = malloc(sizeof(*ring)); - if (!ring) + if (!ring) { + close(file_fd); + free(fi); return 1; - + } memset(ring, 0, sizeof(struct io_ring)); if (setup_io_uring(ring)) @@ -1060,8 +1064,10 @@ void *allocate_dsa_pasid(void) wq = mmap(NULL, 0x1000, PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd, 0); - if (wq == MAP_FAILED) + if (wq == MAP_FAILED) { + close(fd); perror("mmap"); + } return wq; } -- 2.43.0

7 hours, 21 minutes

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[PATCH] selftests/bpf: close the file descriptor to avoid resource leaks

by Malaya Kumar Rout

Static Analyis for bench_htab_mem.c with cppcheck:error tools/testing/selftests/bpf/benchs/bench_htab_mem.c:284:3: error: Resource leak: fd [resourceLeak] tools/testing/selftests/bpf/prog_tests/sk_assign.c:41:3: error: Resource leak: tc [resourceLeak] fix the issue by closing the file descriptor (fd & tc) when read & fgets operation fails. Signed-off-by: Malaya Kumar Rout <malayarout91(a)gmail.com> --- tools/testing/selftests/bpf/benchs/bench_htab_mem.c | 1 + tools/testing/selftests/bpf/prog_tests/sk_assign.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/benchs/bench_htab_mem.c b/tools/testing/selftests/bpf/benchs/bench_htab_mem.c index 926ee822143e..59746fd2c23a 100644 --- a/tools/testing/selftests/bpf/benchs/bench_htab_mem.c +++ b/tools/testing/selftests/bpf/benchs/bench_htab_mem.c @@ -281,6 +281,7 @@ static void htab_mem_read_mem_cgrp_file(const char *name, unsigned long *value) got = read(fd, buf, sizeof(buf) - 1); if (got <= 0) { *value = 0; + close(fd); return; } buf[got] = 0; diff --git a/tools/testing/selftests/bpf/prog_tests/sk_assign.c b/tools/testing/selftests/bpf/prog_tests/sk_assign.c index 0b9bd1d6f7cc..10a0ab954b8a 100644 --- a/tools/testing/selftests/bpf/prog_tests/sk_assign.c +++ b/tools/testing/selftests/bpf/prog_tests/sk_assign.c @@ -37,8 +37,10 @@ configure_stack(void) tc = popen("tc -V", "r"); if (CHECK_FAIL(!tc)) return false; - if (CHECK_FAIL(!fgets(tc_version, sizeof(tc_version), tc))) + if (CHECK_FAIL(!fgets(tc_version, sizeof(tc_version), tc))) { + pclose(tc); return false; + } if (strstr(tc_version, ", libbpf ")) prog = "test_sk_assign_libbpf.bpf.o"; else -- 2.43.0

8 hours, 4 minutes

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[RFC PATCH 0/6] Deep talk about folio vmap

by Huan Yang

Bingbu reported an issue in [1] that udmabuf vmap failed and in [2], we discussed the scenario of folio vmap due to the misuse of vmap_pfn in udmabuf. We reached the conclusion that vmap_pfn prohibits the use of page-based PFNs: Christoph Hellwig : 'No, vmap_pfn is entirely for memory not backed by pages or folios, i.e. PCIe BARs and similar memory. This must not be mixed with proper folio backed memory.' But udmabuf still need consider HVO based folio's vmap, and need fix vmap issue. This RFC code want to show the two point that I mentioned in [2], and more deep talk it: Point1. simple copy vmap_pfn code, don't bother common vmap_pfn, use by itself and remove pfn_valid check. Point2. implement folio array based vmap(vmap_folios), which can given a range of each folio(offset, nr_pages), so can suit HVO folio's vmap. Patch 1-2 implement point1, and add a test simple set in udmabuf driver. Patch 3-5 implement point2, also can test it. Kasireddy also show that 'another option is to just limit udmabuf's vmap() to only shmem folios'(This I guess folio_test_hugetlb_vmemmap_optimized can help.) But I prefer point2 to solution this issue, and IMO, folio based vmap still need. Compare to page based vmap(or pfn based), we need split each large folio into single page struct, this need more large array struct and more longer iter. If each tail page struct not exist(like HVO), can only use pfn vmap, but there are no common api to do this. In [2], we talked that udmabuf can use hugetlb as the memory provider, and can give a range use. So if HVO used in hugetlb, each folio's tail page may freed, so we can't use page based vmap, only can use pfn based, which show in point1. Further more, Folio based vmap only need record each folio(and offset, nr_pages if range need). For 20MB vmap, page based need 5120 pages(40KB), 2MB folios only need 10 folio(80Byte). Matthew show that Vishal also offered a folio based vmap - vmap_file[3]. This RFC patch want a range based folio, not only a full folio's map(like file's folio), to resolve some problem like HVO's range folio vmap. Please give me more suggestion. Test case: //enable/disable HVO 1. echo [1|0] > /proc/sys/vm/hugetlb_optimize_vmemmap //prepare HUGETLB 2. echo 10 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages 3. ./udmabuf_vmap 4. check output, and dmesg if any warn. [1] https://lore.kernel.org/all/9172a601-c360-0d5b-ba1b-33deba430455@linux.inte… [2] https://lore.kernel.org/lkml/20250312061513.1126496-1-link@vivo.com/ [3] https://lore.kernel.org/linux-mm/20250131001806.92349-1-vishal.moola@gmail.… Huan Yang (6): udmabuf: try fix udmabuf vmap udmabuf: try udmabuf vmap test mm/vmalloc: try add vmap folios range udmabuf: use vmap_range_folios udmabuf: vmap test suit for pages and pfns compare udmabuf: remove no need code drivers/dma-buf/udmabuf.c | 29 +++++++++----------- include/linux/vmalloc.h | 57 +++++++++++++++++++++++++++++++++++++++ mm/vmalloc.c | 47 ++++++++++++++++++++++++++++++++ 3 files changed, 117 insertions(+), 16 deletions(-) -- 2.48.1

8 hours, 17 minutes

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[PATCH v2 0/6] Add support for FEAT_{LS64, LS64_V} and related tests

by Yicong Yang

From: Yicong Yang <yangyicong(a)hisilicon.com> Armv8.7 introduces single-copy atomic 64-byte loads and stores instructions and its variants named under FEAT_{LS64, LS64_V}. Add support for Armv8.7 FEAT_{LS64, LS64_V}: - Add identifying and enabling in the cpufeature list - Expose the support of these features to userspace through HWCAP3 and cpuinfo - Add related hwcap test - Handle the trap of unsupported memory (normal/uncacheable) access in a VM A real scenario for this feature is that the userspace driver can make use of this to implement direct WQE (workqueue entry) - a mechanism to fill WQE directly into the hardware. This patchset also complement with Marc's patchset v2[1] for handling LS64* trapped if not advertised for a VM. [1] https://lore.kernel.org/linux-arm-kernel/20250310122505.2857610-1-maz@kerne… Tested with updated hwcap test: On host: root@localhost:/tmp# dmesg | grep "All CPU(s) started" [ 0.504846] CPU: All CPU(s) started at EL2 root@localhost:/tmp# ./hwcap [...] # LS64 present ok 217 cpuinfo_match_LS64 ok 218 sigill_LS64 ok 219 # SKIP sigbus_LS64 # LS64_V present ok 220 cpuinfo_match_LS64_V ok 221 sigill_LS64_V ok 222 # SKIP sigbus_LS64_V # 115 skipped test(s) detected. Consider enabling relevant config options to improve coverage. # Totals: pass:107 fail:0 xfail:0 xpass:0 skip:115 error:0 On guest: root@localhost:/# dmesg | grep "All CPU(s) started" [ 0.205580] CPU: All CPU(s) started at EL1 root@localhost:/mnt# ./hwcap [...] # LS64 present ok 217 cpuinfo_match_LS64 ok 218 sigill_LS64 ok 219 # SKIP sigbus_LS64 # LS64_V present ok 220 cpuinfo_match_LS64_V ok 221 sigill_LS64_V ok 222 # SKIP sigbus_LS64_V # 115 skipped test(s) detected. Consider enabling relevant config options to improve coverage. # Totals: pass:107 fail:0 xfail:0 xpass:0 skip:115 error:0 Change since v1: - Drop the suppport for LS64_ACCDATA - handle the DABT of unsupported memory type after checking the memory attributes Link: https://lore.kernel.org/linux-arm-kernel/20241202135504.14252-1-yangyicong@… Yicong Yang (6): arm64: Provide basic EL2 setup for FEAT_{LS64, LS64_V} usage at EL0/1 arm64: Add support for FEAT_{LS64, LS64_V} KVM: arm64: Enable FEAT_{LS64, LS64_V} in the supported guest kselftest/arm64: Add HWCAP test for FEAT_{LS64, LS64_V} arm64: Add ESR.DFSC definition of unsupported exclusive or atomic access KVM: arm64: Handle DABT caused by LS64* instructions on unsupported memory Documentation/arch/arm64/booting.rst | 12 +++ Documentation/arch/arm64/elf_hwcaps.rst | 6 ++ arch/arm64/include/asm/el2_setup.h | 12 ++- arch/arm64/include/asm/esr.h | 8 ++ arch/arm64/include/asm/hwcap.h | 2 + arch/arm64/include/asm/kvm_emulate.h | 7 ++ arch/arm64/include/uapi/asm/hwcap.h | 2 + arch/arm64/kernel/cpufeature.c | 51 +++++++++++++ arch/arm64/kernel/cpuinfo.c | 2 + arch/arm64/kvm/inject_fault.c | 35 +++++++++ arch/arm64/kvm/mmu.c | 37 +++++++++- arch/arm64/tools/cpucaps | 2 + tools/testing/selftests/arm64/abi/hwcap.c | 90 +++++++++++++++++++++++ 13 files changed, 264 insertions(+), 2 deletions(-) -- 2.24.0

12 hours, 30 minutes

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[PATCH] selftests/pidfd: align stack to fix SP alignment exception

by Shuai Xue

The pidfd_test fails on the ARM64 platform with the following error: Bail out! pidfd_poll check for premature notification on child thread exec test: Failed When exception-trace is enabled, the kernel logs the details: #echo 1 > /proc/sys/debug/exception-trace #dmesg | tail -n 20 [48628.713023] pidfd_test[1082142]: unhandled exception: SP Alignment, ESR 0x000000009a000000, SP/PC alignment exception in pidfd_test[400000+4000] [48628.713049] CPU: 21 PID: 1082142 Comm: pidfd_test Kdump: loaded Tainted: G W E 6.6.71-3_rc1.al8.aarch64 #1 [48628.713051] Hardware name: AlibabaCloud AliServer-Xuanwu2.0AM-1UC1P-5B/AS1111MG1, BIOS 1.2.M1.AL.P.157.00 07/29/2023 [48628.713053] pstate: 60001800 (nZCv daif -PAN -UAO -TCO -DIT +SSBS BTYPE=-c) [48628.713055] pc : 0000000000402100 [48628.713056] lr : 0000ffff98288f9c [48628.713056] sp : 0000ffffde49daa8 [48628.713057] x29: 0000000000000000 x28: 0000000000000000 x27: 0000000000000000 [48628.713060] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 [48628.713062] x23: 0000000000000000 x22: 0000000000000000 x21: 0000000000400e80 [48628.713065] x20: 0000000000000000 x19: 0000000000402650 x18: 0000000000000000 [48628.713067] x17: 00000000004200d8 x16: 0000ffff98288f40 x15: 0000ffffde49b92c [48628.713070] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [48628.713072] x11: 0000000000001011 x10: 0000000000402100 x9 : 0000000000000010 [48628.713074] x8 : 00000000000000dc x7 : 3861616239346564 x6 : 000000000000000a [48628.713077] x5 : 0000ffffde49daa8 x4 : 000000000000000a x3 : 0000ffffde49daa8 [48628.713079] x2 : 0000ffffde49dadc x1 : 0000ffffde49daa8 x0 : 0000000000000000 According to ARM ARM D1.3.10.2 SP alignment checking: > When the SP is used as the base address of a calculation, regardless of > any offset applied by the instruction, if bits [3:0] of the SP are not > 0b0000, there is a misaligned SP. To fix it, align the stack with 16 bytes. Signed-off-by: Shuai Xue <xueshuai(a)linux.alibaba.com> --- tools/testing/selftests/pidfd/pidfd_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/pidfd/pidfd_test.c b/tools/testing/selftests/pidfd/pidfd_test.c index c081ae91313a..ec161a7c3ff9 100644 --- a/tools/testing/selftests/pidfd/pidfd_test.c +++ b/tools/testing/selftests/pidfd/pidfd_test.c @@ -33,7 +33,7 @@ static bool have_pidfd_send_signal; static pid_t pidfd_clone(int flags, int *pidfd, int (*fn)(void *)) { size_t stack_size = 1024; - char *stack[1024] = { 0 }; + char *stack[1024] __attribute__((aligned(16))) = {0}; #ifdef __ia64__ return __clone2(fn, stack, stack_size, flags | SIGCHLD, NULL, pidfd); -- 2.39.3

1 day, 6 hours

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[PATCH v2 1/2] time/timekeeping: Fix possible inconsistencies in _COARSE clockids

by John Stultz

Lei Chen raised an issue with CLOCK_MONOTONIC_COARSE seeing time inconsistencies. Lei tracked down that this was being caused by the adjustment tk->tkr_mono.xtime_nsec -= offset; which is made to compensate for the unaccumulated cycles in offset when the mult value is adjusted forward, so that the non-_COARSE clockids don't see inconsistencies. However, the _COARSE clockids don't use the mult*offset value in their calculations, so this subtraction can cause the _COARSE clock ids to jump back a bit. Now, by design, this negative adjustment should be fine, because the logic run from timekeeping_adjust() is done after we accumulate approx mult*interval_cycles into xtime_nsec. The accumulated (mult*interval_cycles) will be larger then the (mult_adj*offset) value subtracted from xtime_nsec, and both operations are done together under the tk_core.lock, so the net change to xtime_nsec should always be positive. However, do_adjtimex() calls into timekeeping_advance() as well, since we want to apply the ntp freq adjustment immediately. In this case, we don't return early when the offset is smaller then interval_cycles, so we don't end up accumulating any time into xtime_nsec. But we do go on to call timekeeping_adjust(), which modifies the mult value, and subtracts from xtime_nsec to correct for the new mult value. Here because we did not accumulate anything, we have a window where the _COARSE clockids that don't utilize the mult*offset value, can see an inconsistency. So to fix this, rework the timekeeping_advance() logic a bit so that when we are called from do_adjtimex(), we call timekeeping_forward(), to first accumulate the sub-interval time into xtime_nsec. Then with no unaccumulated cycles in offset, we can do the mult adjustment without worry of the subtraction having an impact. Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Stephen Boyd <sboyd(a)kernel.org> Cc: Anna-Maria Behnsen <anna-maria(a)linutronix.de> Cc: Frederic Weisbecker <frederic(a)kernel.org> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Miroslav Lichvar <mlichvar(a)redhat.com> Cc: linux-kselftest(a)vger.kernel.org Cc: kernel-team(a)android.com Cc: Lei Chen <lei.chen(a)smartx.com> Fixes: da15cfdae033 ("time: Introduce CLOCK_REALTIME_COARSE") Reported-by: Lei Chen <lei.chen(a)smartx.com> Closes: https://lore.kernel.org/lkml/20250310030004.3705801-1-lei.chen@smartx.com/ Diagnosed-by: Thomas Gleixner <tglx(a)linutronix.de> Additional-fixes-by: Thomas Gleixner <tglx(a)linutronix.de> Signed-off-by: John Stultz <jstultz(a)google.com> --- v2: Include fixes from Thomas, dropping the unnecessary clock_set setting, and instead clearing ntp_error, along with some other minor tweaks. --- kernel/time/timekeeping.c | 94 ++++++++++++++++++++++++++++----------- 1 file changed, 69 insertions(+), 25 deletions(-) diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 1e67d076f1955..929846b8b45ab 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -682,20 +682,19 @@ static void timekeeping_update_from_shadow(struct tk_data *tkd, unsigned int act } /** - * timekeeping_forward_now - update clock to the current time + * timekeeping_forward - update clock to given cycle now value * @tk: Pointer to the timekeeper to update + * @cycle_now: Current clocksource read value * * Forward the current clock to update its state since the last call to * update_wall_time(). This is useful before significant clock changes, * as it avoids having to deal with this time offset explicitly. */ -static void timekeeping_forward_now(struct timekeeper *tk) +static void timekeeping_forward(struct timekeeper *tk, u64 cycle_now) { - u64 cycle_now, delta; + u64 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask, + tk->tkr_mono.clock->max_raw_delta); - cycle_now = tk_clock_read(&tk->tkr_mono); - delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask, - tk->tkr_mono.clock->max_raw_delta); tk->tkr_mono.cycle_last = cycle_now; tk->tkr_raw.cycle_last = cycle_now; @@ -710,6 +709,21 @@ static void timekeeping_forward_now(struct timekeeper *tk) } } +/** + * timekeeping_forward_now - update clock to the current time + * @tk: Pointer to the timekeeper to update + * + * Forward the current clock to update its state since the last call to + * update_wall_time(). This is useful before significant clock changes, + * as it avoids having to deal with this time offset explicitly. + */ +static void timekeeping_forward_now(struct timekeeper *tk) +{ + u64 cycle_now = tk_clock_read(&tk->tkr_mono); + + timekeeping_forward(tk, cycle_now); +} + /** * ktime_get_real_ts64 - Returns the time of day in a timespec64. * @ts: pointer to the timespec to be set @@ -2151,6 +2165,54 @@ static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset, return offset; } +static u64 timekeeping_accumulate(struct timekeeper *tk, u64 offset, + enum timekeeping_adv_mode mode, + unsigned int *clock_set) +{ + int shift = 0, maxshift; + + /* + * TK_ADV_FREQ indicates that adjtimex(2) directly set the + * frequency or the tick length. + * + * Accumulate the offset, so that the new multiplier starts from + * now. This is required as otherwise for offsets, which are + * smaller than tk::cycle_interval, timekeeping_adjust() could set + * xtime_nsec backwards, which subsequently causes time going + * backwards in the coarse time getters. But even for the case + * where offset is greater than tk::cycle_interval the periodic + * accumulation does not have much value. + * + * Also reset tk::ntp_error as it does not make sense to keep the + * old accumulated error around in this case. + */ + if (mode == TK_ADV_FREQ) { + timekeeping_forward(tk, tk->tkr_mono.cycle_last + offset); + tk->ntp_error = 0; + return 0; + } + + /* + * With NO_HZ we may have to accumulate many cycle_intervals + * (think "ticks") worth of time at once. To do this efficiently, + * we calculate the largest doubling multiple of cycle_intervals + * that is smaller than the offset. We then accumulate that + * chunk in one go, and then try to consume the next smaller + * doubled multiple. + */ + shift = ilog2(offset) - ilog2(tk->cycle_interval); + shift = max(0, shift); + /* Bound shift to one less than what overflows tick_length */ + maxshift = (64 - (ilog2(ntp_tick_length()) + 1)) - 1; + shift = min(shift, maxshift); + while (offset >= tk->cycle_interval) { + offset = logarithmic_accumulation(tk, offset, shift, clock_set); + if (offset < tk->cycle_interval << shift) + shift--; + } + return offset; +} + /* * timekeeping_advance - Updates the timekeeper to the current time and * current NTP tick length @@ -2160,7 +2222,6 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode) struct timekeeper *tk = &tk_core.shadow_timekeeper; struct timekeeper *real_tk = &tk_core.timekeeper; unsigned int clock_set = 0; - int shift = 0, maxshift; u64 offset; guard(raw_spinlock_irqsave)(&tk_core.lock); @@ -2177,24 +2238,7 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode) if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK) return false; - /* - * With NO_HZ we may have to accumulate many cycle_intervals - * (think "ticks") worth of time at once. To do this efficiently, - * we calculate the largest doubling multiple of cycle_intervals - * that is smaller than the offset. We then accumulate that - * chunk in one go, and then try to consume the next smaller - * doubled multiple. - */ - shift = ilog2(offset) - ilog2(tk->cycle_interval); - shift = max(0, shift); - /* Bound shift to one less than what overflows tick_length */ - maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1; - shift = min(shift, maxshift); - while (offset >= tk->cycle_interval) { - offset = logarithmic_accumulation(tk, offset, shift, &clock_set); - if (offset < tk->cycle_interval<<shift) - shift--; - } + offset = timekeeping_accumulate(tk, offset, mode, &clock_set); /* Adjust the multiplier to correct NTP error */ timekeeping_adjust(tk, offset); -- 2.49.0.395.g12beb8f557-goog

1 day, 20 hours

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[PATCH v2 00/16] selftests: vDSO: parse_vdso: Make compatible with nolibc

by Thomas Weißschuh

For testing the functionality of the vDSO, it is necessary to build userspace programs for multiple different architectures. It is additional work to acquire matching userspace cross-compilers with full C libraries and then building root images out of those. The kernel tree already contains nolibc, a small, header-only C library. By using it, it is possible to build userspace programs without any additional dependencies. For example the kernel.org crosstools or multi-target clang can be used to build test programs for a multitude of architectures. While nolibc is very limited, it is enough for many selftests. With some minor adjustments it is possible to make parse_vdso.c compatible with nolibc. As an example, vdso_standalone_test_x86 is now built from the same C code as the regular vdso_test_gettimeofday, while still being completely standalone. Also drop the dependency of parse_vdso.c on the elf.h header from libc and only use the one from the kernel's UAPI. While this series is useful on its own now, it will also integrate with the kunit UAPI framework currently under development: https://lore.kernel.org/lkml/20250217-kunit-kselftests-v1-0-42b4524c3b0a@li… Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- Changes in v2: - Provide a limits.h header in nolibc - Pick up Reviewed-by tags from Kees - Link to v1: https://lore.kernel.org/r/20250203-parse_vdso-nolibc-v1-0-9cb6268d77be@linu… --- Thomas Weißschuh (16): MAINTAINERS: Add vDSO selftests elf, uapi: Add definition for STN_UNDEF elf, uapi: Add definition for DT_GNU_HASH elf, uapi: Add definitions for VER_FLG_BASE and VER_FLG_WEAK elf, uapi: Add type ElfXX_Versym elf, uapi: Add types ElfXX_Verdef and ElfXX_Veraux tools/include: Add uapi/linux/elf.h selftests: Add headers target tools/nolibc: add limits.h shim header selftests: vDSO: vdso_standalone_test_x86: Use vdso_init_form_sysinfo_ehdr selftests: vDSO: parse_vdso: Drop vdso_init_from_auxv() selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers selftests: vDSO: parse_vdso: Test __SIZEOF_LONG__ instead of ULONG_MAX selftests: vDSO: vdso_test_gettimeofday: Clean up includes selftests: vDSO: vdso_test_gettimeofday: Make compatible with nolibc selftests: vDSO: vdso_standalone_test_x86: Switch to nolibc MAINTAINERS | 1 + include/uapi/linux/elf.h | 38 ++ tools/include/nolibc/Makefile | 1 + tools/include/nolibc/limits.h | 7 + tools/include/uapi/linux/elf.h | 524 +++++++++++++++++++++ tools/testing/selftests/lib.mk | 5 +- tools/testing/selftests/vDSO/Makefile | 11 +- tools/testing/selftests/vDSO/parse_vdso.c | 19 +- tools/testing/selftests/vDSO/parse_vdso.h | 1 - .../selftests/vDSO/vdso_standalone_test_x86.c | 143 +----- .../selftests/vDSO/vdso_test_gettimeofday.c | 4 +- 11 files changed, 590 insertions(+), 164 deletions(-) --- base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b change-id: 20241017-parse_vdso-nolibc-e069baa7ff48 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

3 days, 5 hours

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[PATCH bpf v2 0/2] bpf, xdp: clean adjust_{head,meta} memory when offset < 0

by Jiayuan Chen

This patchset originates from my attempt to resolve a KMSAN warning that has existed for over 3 years: https://syzkaller.appspot.com/bug?extid=0e6ddb1ef80986bdfe64 Previously, we had a brief discussion in this thread about whether we can simply perform memset in adjust_{head,meta}: https://lore.kernel.org/netdev/20250328043941.085de23b@kernel.org/T/#t Unfortunately, I couldn't find a similar topic in the mail list, but I did find a similar security-related commit: commit 6dfb970d3dbd ("xdp: avoid leaking info stored in frame data on page reuse") I just create a new topic here and make subject more clear, we can discuss this here. Meanwhile, I also discovered a related issue that led to a CVE,specifically the Facebook Katran vulnerability (https://vuldb.com/?id.246309). Currently, even with unprivileged functionality disabled, a user can load a BPF program using CAP_BPF and CAP_NET_ADMIN, which I believe we should avoid exposing kernel memory directly to users now. Regarding performance considerations, I added corresponding results to the selftest, testing common MAC headers and IP headers of various sizes. Compared to not using memset, the execution time increased by 2ns, but I think this is negligible considering the entire net stack. Jiayuan Chen (2): bpf, xdp: clean head/meta when expanding it selftests/bpf: add perf test for adjust_{head,meta} include/uapi/linux/bpf.h | 8 +-- net/core/filter.c | 5 +- tools/include/uapi/linux/bpf.h | 6 ++- .../selftests/bpf/prog_tests/xdp_perf.c | 52 ++++++++++++++++--- tools/testing/selftests/bpf/progs/xdp_dummy.c | 14 +++++ 5 files changed, 72 insertions(+), 13 deletions(-) -- 2.47.1

3 days, 17 hours

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Linux-kselftest-mirror March 2025