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    Subject[PATCH v3 00/23] Add generic vdso_base tracking
    Date
    v3 Changes:
    - Migrated arch/powerpc to vdso_base
    - Added x86/selftest for unmapped vdso & no landing on fast syscall
    - Review comments from Andy & Christophe (thanks!)
    - Amended s/born process/execed process/ everywhere I noticed
    - Build robot warning on cast from __user pointer

    I've tested it on x86, I would appreciate any help with
    Tested-by on arm/arm64/mips/powerpc/s390/... platforms.

    One thing I've noticed while cooking this and haven't found a clean
    way to solve is zero-terminated .pages[] array in vdso mappings, which
    is not always zero-terminated but works by the reason of
    VM_DONTEXPAND on mappings.

    v2 Changes:
    - Rename user_landing to vdso_base as it tracks vDSO VMA start address,
    rather than the explicit address to land (Andy)
    - Reword and don't use "new-execed" and "new-born" task (Andy)
    - Fix failures reported by build robot

    Started from discussion [1], where was noted that currently a couple of
    architectures support mremap() for vdso/sigpage, but not munmap().
    If an application maps something on the ex-place of vdso/sigpage,
    later after processing signal it will land there (good luck!)

    Patches set is based on linux-next (next-20201123) and it depends on
    changes in x86/cleanups (those reclaim TIF_IA32/TIF_X32) and also
    on my changes in akpm (fixing several mremap() issues).

    Logically, the patches set divides on:
    - patch 1: a cleanup for patches in x86/cleanups
    - patches 2-13: cleanups for arch_setup_additional_pages()
    - patches 13-14: x86 signal changes for unmapped vdso
    - patches 15-22: provide generic vdso_base in mm_struct
    - patch 23: selftest for unmapped vDSO & fast syscalls

    In the end, besides cleanups, it's now more predictable what happens for
    applications with unmapped vdso on architectures those support .mremap()
    for vdso/sigpage.

    I'm aware of only one user that unmaps vdso - Valgrind [2].
    (there possibly are more, but this one is "special", it unmaps vdso, but
    not vvar, which confuses CRIU [Checkpoint Restore In Userspace], that's
    why I'm aware of it)

    Patches as a .git branch:
    https://github.com/0x7f454c46/linux/tree/vdso_base-v3

    v2 Link:
    https://lore.kernel.org/lkml/20201124002932.1220517-1-dima@arista.com/
    v1 Link:
    https://lore.kernel.org/lkml/20201108051730.2042693-1-dima@arista.com/

    [1]: https://lore.kernel.org/linux-arch/CAJwJo6ZANqYkSHbQ+3b+Fi_VT80MtrzEV5yreQAWx-L8j8x2zA@mail.gmail.com/
    [2]: https://github.com/checkpoint-restore/criu/issues/488

    Cc: Alexander Viro <viro@zeniv.linux.org.uk>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
    Cc: Guo Ren <guoren@kernel.org>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Oleg Nesterov <oleg@redhat.com>
    Cc: Russell King <linux@armlinux.org.uk>
    Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
    Cc: Will Deacon <will@kernel.org>
    Cc: x86@kernel.org

    Dmitry Safonov (23):
    x86/elf: Check in_x32_syscall() in
    compat_arch_setup_additional_pages()
    elf: Move arch_setup_additional_pages() to generic elf.h
    arm/elf: Remove needless ifdef CONFIG_MMU
    arm64: Use in_compat_task() in arch_setup_additional_pages()
    x86: Remove compat_arch_setup_additional_pages()
    elf: Remove compat_arch_setup_additional_pages()
    vdso: Set mm->context.vdso only on success of
    _install_special_mapping()
    elf/vdso: Modify arch_setup_additional_pages() parameters
    elf: Use sysinfo_ehdr in ARCH_DLINFO()
    arm/vdso: Remove vdso pointer from mm->context
    s390/vdso: Remove vdso_base pointer from mm->context
    sparc/vdso: Remove vdso pointer from mm->context
    mm/mmap: Make vm_special_mapping::mremap return void
    x86/signal: Land on &frame->retcode when vdso isn't mapped
    x86/signal: Check if vdso_image_32 is mapped before trying to land on it
    mm: Add vdso_base in mm_struct
    x86/vdso: Migrate to generic vdso_base
    arm/vdso: Migrate to generic vdso_base
    arm64/vdso: Migrate compat signals to generic vdso_base
    arm64/vdso: Migrate native signals to generic vdso_base
    mips/vdso: Migrate to generic vdso_base
    powerpc/vdso: Migrate native signals to generic vdso_base
    x86/vdso/selftest: Add a test for unmapping vDSO

    arch/Kconfig | 3 +
    arch/alpha/include/asm/elf.h | 2 +-
    arch/arm/Kconfig | 2 +
    arch/arm/include/asm/elf.h | 10 +-
    arch/arm/include/asm/mmu.h | 3 -
    arch/arm/include/asm/vdso.h | 6 +-
    arch/arm/kernel/process.c | 14 +-
    arch/arm/kernel/signal.c | 6 +-
    arch/arm/kernel/vdso.c | 20 +--
    arch/arm64/Kconfig | 2 +
    arch/arm64/include/asm/elf.h | 27 +---
    arch/arm64/include/asm/mmu.h | 4 -
    arch/arm64/kernel/signal.c | 10 +-
    arch/arm64/kernel/signal32.c | 17 +-
    arch/arm64/kernel/vdso.c | 72 +++------
    arch/csky/Kconfig | 1 +
    arch/csky/include/asm/elf.h | 4 -
    arch/csky/kernel/vdso.c | 11 +-
    arch/hexagon/Kconfig | 1 +
    arch/hexagon/include/asm/elf.h | 6 -
    arch/hexagon/kernel/vdso.c | 3 +-
    arch/ia64/include/asm/elf.h | 2 +-
    arch/mips/Kconfig | 2 +
    arch/mips/include/asm/elf.h | 10 +-
    arch/mips/include/asm/mmu.h | 2 -
    arch/mips/kernel/signal.c | 11 +-
    arch/mips/kernel/vdso.c | 5 +-
    arch/mips/vdso/genvdso.c | 9 --
    arch/nds32/Kconfig | 1 +
    arch/nds32/include/asm/elf.h | 8 +-
    arch/nds32/kernel/vdso.c | 8 +-
    arch/nios2/Kconfig | 1 +
    arch/nios2/include/asm/elf.h | 4 -
    arch/nios2/mm/init.c | 2 +-
    arch/powerpc/Kconfig | 2 +
    arch/powerpc/include/asm/book3s/32/mmu-hash.h | 1 -
    arch/powerpc/include/asm/book3s/64/mmu.h | 1 -
    arch/powerpc/include/asm/elf.h | 9 +-
    arch/powerpc/include/asm/mmu_context.h | 9 --
    arch/powerpc/include/asm/nohash/32/mmu-40x.h | 1 -
    arch/powerpc/include/asm/nohash/32/mmu-44x.h | 1 -
    arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 1 -
    arch/powerpc/include/asm/nohash/mmu-book3e.h | 1 -
    arch/powerpc/kernel/signal_32.c | 8 +-
    arch/powerpc/kernel/signal_64.c | 4 +-
    arch/powerpc/kernel/vdso.c | 48 +-----
    arch/powerpc/perf/callchain_32.c | 8 +-
    arch/powerpc/perf/callchain_64.c | 4 +-
    arch/riscv/Kconfig | 1 +
    arch/riscv/include/asm/elf.h | 9 +-
    arch/riscv/kernel/vdso.c | 11 +-
    arch/s390/Kconfig | 1 +
    arch/s390/include/asm/elf.h | 10 +-
    arch/s390/include/asm/mmu.h | 1 -
    arch/s390/kernel/vdso.c | 12 +-
    arch/sh/Kconfig | 1 +
    arch/sh/include/asm/elf.h | 16 +-
    arch/sh/kernel/vsyscall/vsyscall.c | 3 +-
    arch/sparc/Kconfig | 1 +
    arch/sparc/include/asm/elf_64.h | 11 +-
    arch/sparc/include/asm/mmu_64.h | 1 -
    arch/sparc/vdso/vma.c | 20 +--
    arch/x86/Kconfig | 2 +
    arch/x86/entry/common.c | 10 +-
    arch/x86/entry/vdso/extable.c | 4 +-
    arch/x86/entry/vdso/vma.c | 79 ++++-----
    arch/x86/ia32/ia32_signal.c | 18 ++-
    arch/x86/include/asm/compat.h | 6 +
    arch/x86/include/asm/elf.h | 44 ++---
    arch/x86/include/asm/mmu.h | 1 -
    arch/x86/include/asm/mmu_context.h | 5 -
    arch/x86/include/asm/vdso.h | 4 +
    arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 3 +-
    arch/x86/kernel/signal.c | 25 ++-
    arch/x86/um/asm/elf.h | 9 +-
    arch/x86/um/vdso/vma.c | 2 +-
    fs/Kconfig.binfmt | 3 +
    fs/aio.c | 3 +-
    fs/binfmt_elf.c | 19 ++-
    fs/binfmt_elf_fdpic.c | 17 +-
    fs/compat_binfmt_elf.c | 12 --
    include/asm-generic/mm_hooks.h | 9 +-
    include/linux/elf.h | 24 ++-
    include/linux/mm.h | 3 +-
    include/linux/mm_types.h | 21 ++-
    kernel/fork.c | 1 +
    mm/mmap.c | 28 ++--
    mm/mremap.c | 2 +-
    tools/testing/selftests/x86/.gitignore | 1 +
    tools/testing/selftests/x86/Makefile | 11 +-
    .../testing/selftests/x86/test_munmap_vdso.c | 151 ++++++++++++++++++
    91 files changed, 511 insertions(+), 491 deletions(-)
    create mode 100644 tools/testing/selftests/x86/test_munmap_vdso.c


    base-commit: 614124bea77e452aa6df7a8714e8bc820b489922
    --
    2.31.1

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