[PATCH v2 0/6] unwind, arm64: add sframe unwinder for kernel

[Dylan Hatch]

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 proposals
could integrate common functionality in the future.

Currently, only GCC supports sframe.

These patches are based on v6.17-rc4 and are available on github [3].

Ref:
[1]: https://sourceware.org/binutils/docs/sframe-spec.html
[2]: https://lore.kernel.org/lkml/cover.1730150953.git.jpoimboe@xxxxxxxxxx/
[3]: https://github.com/dylanbhatch/linux/tree/sframe-v2

Changes since v1:
https://lore.kernel.org/live-patching/20250127213310.2496133-1-wnliu@xxxxxxxxxx/

 - Fixed detection of sframe support in compiler (Josh, Jens)
 - Adapt latest sframe v2 header definition from userspace patch series
   (Josh)
 - Folded together unwinder/stacktrace patches (Prasanna)
 - Fix "orphan section" warnings for .init.sframe sections (Puranjay,
   Indu, Josh)
 - Build VDSO without sframe (Dylan)
 - Added support for modules (Weinan)

Dylan Hatch (2):
  unwind: build kernel with sframe info
  unwind: add sframe v2 header

Weinan Liu (4):
  arm64: entry: add unwind info for various kernel entries
  unwind: Implement generic sframe unwinder library
  arm64/module, unwind: Add sframe support for modules.
  unwind: arm64: Add reliable stacktrace with sframe unwinder.

 Makefile                                   |   8 +
 arch/Kconfig                               |   6 +
 arch/arm64/Kconfig.debug                   |  10 +
 arch/arm64/include/asm/module.h            |   6 +
 arch/arm64/include/asm/stacktrace/common.h |   6 +
 arch/arm64/kernel/entry.S                  |  10 +
 arch/arm64/kernel/module.c                 |   5 +
 arch/arm64/kernel/setup.c                  |   2 +
 arch/arm64/kernel/stacktrace.c             | 102 +++++++++
 arch/arm64/kernel/vdso/Makefile            |   2 +-
 include/asm-generic/vmlinux.lds.h          |  15 ++
 include/linux/sframe_lookup.h              |  45 ++++
 kernel/Makefile                            |   1 +
 kernel/sframe.h                            |  75 +++++++
 kernel/sframe_lookup.c                     | 232 +++++++++++++++++++++
 15 files changed, 524 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/sframe_lookup.h
 create mode 100644 kernel/sframe.h
 create mode 100644 kernel/sframe_lookup.c

-- 
2.51.0.355.g5224444f11-goog