[PATCH 0/8] unwind, arm64: add sframe unwinder for kernel

This patchset implements a generic kernel sframe-based [1] unwinder.
The main goal is to support reliable stacktraces on arm64.

On x86 orc unwinder provides reliable stacktraces. But arm64 misses the
required support from objtool: it cannot generate orc unwind tables for
arm64.

Currently, there's already a sframe unwinder proposed for userspace: [2].
Since the sframe unwind table algorithm is similar, these two proposal
could integrate common functionality in the future.

There are some incomplete features or challenges:
  - The unwinder doesn't yet work with kernel modules. The `start_addr` of
    FRE from kernel modules doesn't appear correct, preventing us from
    unwinding functions from kernel modules.
  - Currently, only GCC supports sframe.

Ref:
[1]: https://sourceware.org/binutils/docs/sframe-spec.html
[2]: https://lore.kernel.org/lkml/[email protected]/

Madhavan T. Venkataraman (1):
  arm64: Define TIF_PATCH_PENDING for livepatch

Weinan Liu (7):
  unwind: build kernel with sframe info
  arm64: entry: add unwind info for various kernel entries
  unwind: add sframe v2 header
  unwind: Implement generic sframe unwinder library
  unwind: arm64: Add sframe unwinder on arm64
  unwind: arm64: add reliable stacktrace support for arm64
  arm64: Enable livepatch for ARM64

 Makefile                                   |   6 +
 arch/Kconfig                               |   8 +
 arch/arm64/Kconfig                         |   3 +
 arch/arm64/Kconfig.debug                   |  10 +
 arch/arm64/include/asm/stacktrace/common.h |   6 +
 arch/arm64/include/asm/thread_info.h       |   4 +-
 arch/arm64/kernel/entry-common.c           |   4 +
 arch/arm64/kernel/entry.S                  |  10 +
 arch/arm64/kernel/setup.c                  |   2 +
 arch/arm64/kernel/stacktrace.c             | 102 ++++++++++
 include/asm-generic/vmlinux.lds.h          |  12 ++
 include/linux/sframe_lookup.h              |  43 +++++
 kernel/Makefile                            |   1 +
 kernel/sframe.h                            | 215 +++++++++++++++++++++
 kernel/sframe_lookup.c                     | 196 +++++++++++++++++++
 15 files changed, 621 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/sframe_lookup.h
 create mode 100644 kernel/sframe.h
 create mode 100644 kernel/sframe_lookup.c

-- 
2.48.1.262.g85cc9f2d1e-goog