Hi, This is the third version (second 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-v3 Changes in this version: - Ignore asynchronous tag check faults caused by the kernel accessing user space (uaccess routines). One of the reasons is that the kernel has a few places where it over-reads the user buffer (copy_mount_options(), strncpy_from user()) causing an incorrect reporting of a tag check fault. The second reason is that such asynchronous tag check fault in uaccess was reported as a SIGSEGV while the uaccess synchronous faults usually cause an error being returned (-EFAULT). - Device Tree support for marking a memory node as MTE-capable. MTE will only be enabled if all the memory nodes support the feature. In the absence of any memory node in the DT or if the system is booted with ACPI, MTE will be disabled. - ptrace() support to access the tags in another process address space. See the documentation patch for details. - fs patch for copy_mount_options() to cope with in-page faults. Prior to 5.7, this function had a byte-by-byte fallback. It has since been updated so that a fault in the first page would lead to the copy being aborted altogether. - GCR_EL1 restoring after a CPU suspend. - Fix the pgattr_change_is_safe() to only allow changes between Normal and Normal-Tagged. - Update a BUILD_BUG on x86 for NSIGSEGV != 7 following the generic value update. - Rebased to 5.7-rc2. Swap support is available but not included with this series as we'd like some feedback from linux-mm folk on the right approach. To be posted shortly. Kselftest patches will also be made available soon. To be decided/implemented: - mmap(tagged_addr, PROT_MTE) pre-tagging the memory with the tag given in the tagged_addr hint. - coredump (user) to also dump the tags. [1] https://lore.kernel.org/linux-arm-kernel/20200226180526.3272848-1-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: alternative: Allow alternative_insn to always issue the first instruction arm64: mte: Use Normal Tagged attributes for the linear map arm64: mte: Assembler macros and default architecture for .S files arm64: Tags-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: Allow copy_mount_options() to access user-space in a single pass arm64: mte: Check the DT memory nodes for MTE support Kevin Brodsky (1): mm: Introduce arch_calc_vm_flag_bits() Vincenzo Frascino (8): arm64: mte: system register definitions arm64: mte: CPU feature detection and initial sysreg configuration arm64: mte: Tags-aware clear_page() implementation arm64: mte: Tags-aware copy_page() implementation arm64: mte: Add specific SIGSEGV codes arm64: mte: Handle synchronous and asynchronous tag check faults arm64: mte: Kconfig entry arm64: mte: Add Memory Tagging Extension documentation Documentation/arm64/cpu-feature-registers.rst | 2 + Documentation/arm64/elf_hwcaps.rst | 5 + Documentation/arm64/index.rst | 1 + .../arm64/memory-tagging-extension.rst | 260 +++++++++++++++++ arch/arm64/Kconfig | 32 +++ arch/arm64/boot/dts/arm/fvp-base-revc.dts | 1 + arch/arm64/include/asm/alternative.h | 8 +- arch/arm64/include/asm/assembler.h | 17 ++ arch/arm64/include/asm/cpucaps.h | 4 +- arch/arm64/include/asm/cpufeature.h | 6 + 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 | 56 ++++ arch/arm64/include/asm/page.h | 2 +- arch/arm64/include/asm/pgtable-prot.h | 2 + arch/arm64/include/asm/pgtable.h | 7 +- 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/asm/uaccess.h | 11 + 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 | 107 +++++++ arch/arm64/kernel/cpuinfo.c | 2 + arch/arm64/kernel/entry.S | 36 +++ arch/arm64/kernel/mte.c | 262 ++++++++++++++++++ arch/arm64/kernel/process.c | 31 ++- arch/arm64/kernel/ptrace.c | 17 +- 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/clear_page.S | 7 +- arch/arm64/lib/copy_page.S | 23 ++ arch/arm64/lib/mte.S | 96 +++++++ arch/arm64/mm/Makefile | 1 + arch/arm64/mm/cmppages.c | 26 ++ arch/arm64/mm/dump.c | 4 + arch/arm64/mm/fault.c | 9 +- arch/arm64/mm/mmu.c | 22 +- arch/arm64/mm/proc.S | 8 +- arch/x86/kernel/signal_compat.c | 2 +- fs/namespace.c | 7 +- fs/proc/task_mmu.c | 4 + include/linux/mm.h | 8 + include/linux/mman.h | 22 +- include/linux/uaccess.h | 8 + include/uapi/asm-generic/siginfo.h | 4 +- include/uapi/linux/prctl.h | 9 + mm/mmap.c | 9 + mm/mprotect.c | 6 + mm/shmem.c | 3 + mm/util.c | 2 +- 57 files changed, 1332 insertions(+), 31 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/cmppages.c
