[PATCH v2 00/19] Add generic vdso_base tracking

Dmitry Safonov
2020-11-24T00:29:58Z

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 2-11: cleanups for arch_setup_additional_pages()
- patches 12-13: x86 signal changes for unmapped vdso
- patches 14-19: provide generic vdso_base in mm_struct

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/setup_additional_pages-v2

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 (19):
x86/elf: Check in_x32_syscall() in compat_arch_setup_additional_pages()
elf: Move arch_setup_additional_pages() to generic elf.h
arm64: Use in_compat_task() in arch_setup_additional_pages()
x86: Remove compat_arch_setup_additional_pages()
elf: Remove compat_arch_setup_additional_pages()
elf/vdso: Reuse 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

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/kernel/signal.c | 10 +++-
arch/arm64/kernel/signal32.c | 17 ++++--
arch/arm64/kernel/vdso.c | 50 +++++++---------
arch/csky/Kconfig | 1 +
arch/csky/include/asm/elf.h | 4 --
arch/csky/kernel/vdso.c | 3 +-
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/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 | 3 +-
arch/nios2/Kconfig | 1 +
arch/nios2/include/asm/elf.h | 4 --
arch/nios2/mm/init.c | 2 +-
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/elf.h | 9 +--
arch/powerpc/kernel/vdso.c | 3 +-
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 | 13 +---
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 | 18 +++---
arch/x86/Kconfig | 2 +
arch/x86/entry/common.c | 7 ++-
arch/x86/entry/vdso/extable.c | 4 +-
arch/x86/entry/vdso/vma.c | 72 ++++++++++++-----------
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/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/linux/elf.h | 24 ++++++--
include/linux/mm.h | 3 +-
include/linux/mm_types.h | 12 +++-
mm/Kconfig | 3 +
mm/mmap.c | 21 ++++++-
mm/mremap.c | 2 +-
72 files changed, 313 insertions(+), 358 deletions(-)

base-commit: 62918e6fd7b5751c1285c7f8c6cbd27eb6600c02
--
2.29.2