This is the fourth version (third version here [1]) of the series adding user-space support for the ARMv8.5 Memory Tagging Extension ([2], [3]). The patches are also available on this branch: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux devel/mte-v4 Changes in this version: - Swap and suspend to disk support for saving/restoring tags. - Deferred the tag zeroing from clear_page() to set_pte_at() to cope with RAM filesystems that do not start from a zeroed page. The copy_page() function was also optimised to only copy tags if the page has been previously mapped as tagged (PROT_MTE). This mechanism requires a new PG_arch_2 flag. - memcmp_pages() rewritten to always return a no-match if at least one of the pages is tagged (tag comparison avoided). - ptrace() updated to prevent accessing tags in a page that has not been mapped with PROT_MTE (PG_arch_2 flag not set). - copy_mount_options() fix re-implemented to avoid arch_has_exact_copy_from_user(). - The CPUID handling has been reworked to ensure that, when the feature is not backed by the DT, the HWCAP is also hidden from user. Note that the DT description is still under internal discussion on whether we need it or not. - A new early param, arm64.mte_disable, was introduced to facilitate testing with and without MTE on platforms that support it. - Asynchronous TCF SIGSEGV is no longer forced, so it can be ignored but the user thread. - CONFIG_ARM64_MTE is now default y since swap is supported. To do or discuss: - prctl() accepting an include vs exclude mask for the GCR_EL1.Excl field. There is an ongoing discussion on v3 which accepts an include mask with 0 being a special case equivalent to 1. If this is not desirable, we can change this to an exclude mask. - mmap(tagged_addr, PROT_MTE) pre-tagging the memory with the tag given in the tagged_addr hint. - ptrace() to expose the prctl() configuration for the user thread (or the TCF and GCR_EL1.Excl fields). - coredump (user) to also dump the tags. - Kselftest patches will be made available. [1] https://lore.kernel.org/linux-arm-kernel/20200421142603.3894-1-catalin.marinas@xxxxxxx/ [2] https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/enhancing-memory-safety [3] https://developer.arm.com/-/media/Arm%20Developer%20Community/PDF/Arm_Memory_Tagging_Extension_Whitepaper.pdf Catalin Marinas (14): arm64: mte: Use Normal Tagged attributes for the linear map arm64: mte: Clear the tags when a page is mapped in user-space with PROT_MTE arm64: mte: Tags-aware aware memcmp_pages() implementation arm64: mte: Add PROT_MTE support to mmap() and mprotect() mm: Introduce arch_validate_flags() arm64: mte: Validate the PROT_MTE request via arch_validate_flags() mm: Allow arm64 mmap(PROT_MTE) on RAM-based files arm64: mte: Allow user control of the tag check mode via prctl() arm64: mte: Allow user control of the generated random tags via prctl() arm64: mte: Restore the GCR_EL1 register after a suspend arm64: mte: Add PTRACE_{PEEK,POKE}MTETAGS support fs: Handle intra-page faults in copy_mount_options() arm64: mte: Check the DT memory nodes for MTE support arm64: mte: Introduce early param to disable MTE support Kevin Brodsky (1): mm: Introduce arch_calc_vm_flag_bits() Steven Price (4): mm: Add PG_ARCH_2 page flag mm: Add arch hooks for saving/restoring tags arm64: mte: Enable swap of tagged pages arm64: mte: Save tags when hibernating Vincenzo Frascino (7): arm64: mte: system register definitions arm64: mte: CPU feature detection and initial sysreg configuration arm64: mte: Add specific SIGSEGV codes arm64: mte: Handle synchronous and asynchronous tag check faults arm64: mte: Tags-aware copy_page() implementation arm64: mte: Kconfig entry arm64: mte: Add Memory Tagging Extension documentation .../admin-guide/kernel-parameters.txt | 4 + Documentation/arm64/cpu-feature-registers.rst | 2 + Documentation/arm64/elf_hwcaps.rst | 5 + Documentation/arm64/index.rst | 1 + .../arm64/memory-tagging-extension.rst | 297 ++++++++++++++++ arch/arm64/Kconfig | 33 ++ arch/arm64/boot/dts/arm/fvp-base-revc.dts | 1 + arch/arm64/include/asm/assembler.h | 12 + arch/arm64/include/asm/cpucaps.h | 4 +- arch/arm64/include/asm/cpufeature.h | 12 +- arch/arm64/include/asm/hwcap.h | 1 + arch/arm64/include/asm/kvm_arm.h | 3 +- arch/arm64/include/asm/memory.h | 17 +- arch/arm64/include/asm/mman.h | 78 +++++ arch/arm64/include/asm/mte.h | 86 +++++ arch/arm64/include/asm/page.h | 2 +- arch/arm64/include/asm/pgtable-prot.h | 2 + arch/arm64/include/asm/pgtable.h | 45 ++- arch/arm64/include/asm/processor.h | 4 + arch/arm64/include/asm/sysreg.h | 62 ++++ arch/arm64/include/asm/thread_info.h | 4 +- arch/arm64/include/uapi/asm/hwcap.h | 2 + arch/arm64/include/uapi/asm/mman.h | 14 + arch/arm64/include/uapi/asm/ptrace.h | 4 + arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/cpufeature.c | 126 ++++++- arch/arm64/kernel/cpuinfo.c | 2 + arch/arm64/kernel/entry.S | 37 ++ arch/arm64/kernel/hibernate.c | 118 +++++++ arch/arm64/kernel/mte.c | 324 ++++++++++++++++++ arch/arm64/kernel/process.c | 31 +- arch/arm64/kernel/ptrace.c | 9 +- arch/arm64/kernel/signal.c | 8 + arch/arm64/kernel/suspend.c | 4 + arch/arm64/kernel/syscall.c | 10 + arch/arm64/lib/Makefile | 2 + arch/arm64/lib/mte.S | 140 ++++++++ arch/arm64/mm/Makefile | 1 + arch/arm64/mm/copypage.c | 14 +- arch/arm64/mm/dump.c | 4 + arch/arm64/mm/fault.c | 9 +- arch/arm64/mm/mmu.c | 22 +- arch/arm64/mm/mteswap.c | 82 +++++ arch/arm64/mm/proc.S | 8 +- arch/x86/kernel/signal_compat.c | 2 +- fs/namespace.c | 24 +- fs/proc/page.c | 3 + fs/proc/task_mmu.c | 4 + include/asm-generic/pgtable.h | 23 ++ include/linux/kernel-page-flags.h | 1 + include/linux/mm.h | 8 + include/linux/mman.h | 22 +- include/linux/page-flags.h | 3 + include/trace/events/mmflags.h | 9 +- include/uapi/asm-generic/siginfo.h | 4 +- include/uapi/linux/prctl.h | 9 + mm/Kconfig | 3 + mm/mmap.c | 9 + mm/mprotect.c | 6 + mm/page_io.c | 10 + mm/shmem.c | 9 + mm/swapfile.c | 2 + mm/util.c | 2 +- tools/vm/page-types.c | 2 + 64 files changed, 1765 insertions(+), 37 deletions(-) create mode 100644 Documentation/arm64/memory-tagging-extension.rst create mode 100644 arch/arm64/include/asm/mman.h create mode 100644 arch/arm64/include/asm/mte.h create mode 100644 arch/arm64/include/uapi/asm/mman.h create mode 100644 arch/arm64/kernel/mte.c create mode 100644 arch/arm64/lib/mte.S create mode 100644 arch/arm64/mm/mteswap.c
