Subject: [PATCH v6 0/9] unwind, arm64: add sframe unwinder for kernel

From: Dylan Hatch <[email-masked]>
Date: Tue, 19 May 2026 06:49:41 +0000

Implement a generic kernel sframe-based [1] unwinder. The main goal is
to improve reliable stacktrace on arm64 by unwinding across exception
boundaries.

On x86, the ORC unwinder provides reliable stacktrace through similar
methodology, but arm64 lacks the necessary support from objtool to
create ORC unwind tables.

Currently, there's already a sframe unwinder proposed for userspace: [2].
To maintain common definitions and algorithms for sframe lookup, a
substantial portion of this patch series aims to refactor the sframe
lookup code to support both kernel and userspace sframe sections.

Currently, only GNU Binutils support sframe. This series relies on the
Sframe V3 format, which is supported in binutils 2.46.

These patches are based on Steven Rostedt's sframe/core branch [3],
which is and aggregation of existing work done for x86 sframe userspace
unwind, and contains [2]. This branch is, in turn, based on Linux
v7.1-rc2. This full series (applied to the sframe/core branch) is
available on github: [4].

Ref:
[1]: https://sourceware.org/binutils/docs/sframe-spec.html
[2]: https://lore.kernel.org/all/[email-masked]/
[3]: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git/log/?h=sframe/core
[4]: https://github.com/dylanbhatch/linux/tree/sframe-v6

Changes since v5:
- Rebase on latest sframe/core branch [3] (based on v7.1-rc2).
- (Mark) Drop CFI annotations from el1*_64_* entry functions.
- (Mark) Add CFI annotations for leaf functions in lib/ and crypto/.
- (Jens) Sort module FDEs at load-time, drop linear search method.
- (Jens) Fix mistake in module SFrame validation where temp copy is not
  yet embedded within a struct module.
- (Jens) Initialize debug info for kernel .sframe sections.
- (Mark) Move kernel-specific unwind fields to struct kunwind_state.
- (Mark) Drop SP from unwind state.
- (Mark) Rename unwind_next_frame_sframe -> kunwind_next_regs_sframe,
  add checks to assert a correct KUNWIND_SOURCE_REGS_PC state.
- (Mark) Drop unused flexible FDE handling.
- (Mark) Check CFA alignment to 16 bytes instead of 8 bytes.
- (Mark) For non-KUNWIND_SOURCE_REGS_PC state, drop the fallback to
  SFrame unwind if FP unwind fails in kunwind_next().

Dylan Hatch (8):
  sframe: Allow kernelspace sframe sections
  arm64, unwind: build kernel with sframe V3 info
  arm64, crypto/lib: Annotate leaf functions with CFI info.
  sframe: Provide PC lookup for vmlinux .sframe section
  arm64/module, sframe: Add sframe support for modules
  sframe: Introduce in-kernel SFRAME_VALIDATION
  sframe: Initialize debug info for kernel sections
  unwind: arm64: Use sframe to unwind interrupt frames

Weinan Liu (1):
  arm64: entry: add unwind info for call_on_irq_stack()

 MAINTAINERS                                   |   4 +-
 Makefile                                      |   8 +
 arch/Kconfig                                  |  27 +-
 arch/arm64/Kconfig                            |   1 +
 arch/arm64/crypto/aes-ce-ccm-core.S           |  12 +-
 arch/arm64/crypto/aes-neonbs-core.S           |  40 +-
 arch/arm64/crypto/ghash-ce-core.S             |  20 +-
 arch/arm64/crypto/sm4-ce-ccm-core.S           |  16 +-
 arch/arm64/crypto/sm4-ce-cipher-core.S        |   4 +-
 arch/arm64/crypto/sm4-ce-core.S               |  44 +-
 arch/arm64/crypto/sm4-ce-gcm-core.S           |  16 +-
 arch/arm64/crypto/sm4-neon-core.S             |  12 +-
 arch/arm64/include/asm/linkage.h              |  30 ++
 arch/arm64/include/asm/module.h               |   6 +
 arch/arm64/include/asm/sections.h             |   1 +
 arch/arm64/include/asm/unwind_sframe.h        |  54 +++
 arch/arm64/kernel/entry.S                     |  14 +
 arch/arm64/kernel/module.c                    |   8 +
 arch/arm64/kernel/setup.c                     |   2 +
 arch/arm64/kernel/stacktrace.c                | 222 +++++++++-
 arch/arm64/kernel/vdso/Makefile               |   2 +-
 arch/arm64/kernel/vmlinux.lds.S               |   2 +
 arch/arm64/lib/clear_page.S                   |   4 +-
 arch/arm64/lib/clear_user.S                   |   4 +-
 arch/arm64/lib/copy_from_user.S               |   4 +-
 arch/arm64/lib/copy_page.S                    |   4 +-
 arch/arm64/lib/copy_to_user.S                 |   4 +-
 arch/arm64/lib/memchr.S                       |   4 +-
 arch/arm64/lib/memcmp.S                       |   4 +-
 arch/arm64/lib/memcpy.S                       |   8 +-
 arch/arm64/lib/memset.S                       |   8 +-
 arch/arm64/lib/mte.S                          |  28 +-
 arch/arm64/lib/strchr.S                       |   4 +-
 arch/arm64/lib/strcmp.S                       |   4 +-
 arch/arm64/lib/strlen.S                       |   4 +-
 arch/arm64/lib/strncmp.S                      |   4 +-
 arch/arm64/lib/strnlen.S                      |   4 +-
 arch/arm64/lib/tishift.S                      |  12 +-
 .../{unwind_user_sframe.h => unwind_sframe.h} |   6 +-
 arch/x86/include/asm/unwind_user.h            |  12 +-
 include/asm-generic/sections.h                |   4 +
 include/asm-generic/vmlinux.lds.h             |  15 +
 include/linux/sframe.h                        |  67 ++-
 include/linux/unwind_types.h                  |  46 ++
 include/linux/unwind_user_types.h             |  41 --
 kernel/unwind/Makefile                        |   2 +-
 kernel/unwind/sframe.c                        | 419 ++++++++++++++----
 kernel/unwind/sframe_debug.h                  |  13 +
 kernel/unwind/user.c                          |  45 +-
 49 files changed, 979 insertions(+), 340 deletions(-)
 create mode 100644 arch/arm64/include/asm/unwind_sframe.h
 rename arch/x86/include/asm/{unwind_user_sframe.h => unwind_sframe.h} (50%)
 create mode 100644 include/linux/unwind_types.h

-- 
2.54.0.563.g4f69b47b94-goog