Re: [kvm-unit-tests PATCH v3 0/6] arm64: improve debuggability

[Andrew Jones <andrew.jones@linux.dev>]

On Wed, Jun 28, 2023 at 12:13:49AM +0000, Nadav Amit wrote:
> From: Nadav Amit <namit@vmware.com>
> 
> My recent experience in debugging ARM64 tests on EFI was not as fun as I
> expected it to be.
> 
> There were several reasons for that besides the questionable definition
> of "fun":
> 
> 1. ARM64 is not compiled with frame pointers and there is no stack
>    unwinder when the stack is dumped.
> 
> 2. Building an EFI drops the debug information.
> 
> 3. The addresses that are printed on dump_stack() and the use of GDB
>    are hard because taking code relocation into account is non trivial.
> 
> The patches help both ARM64 and EFI for this matter. The image address
> is printed when EFI is used to allow the use of GDB. Symbols are emitted
> into a separate debug file. The frame pointer is included and special
> entry is added upon an exception to allow backtracing across
> exceptions.
> 
> [ PowerPC: Please ack patches 1,2 ]
> [ x86: Please ack patches 1,2,5 ]
> 
> v2->v3:
> * Consider PowerPC for reloc and related fixes [Andrew]
> 
> v1->v2:
> * Andrew comments [see in individual patches]
> * Few cleanups
> 
> Nadav Amit (6):
>   efi: keep efi debug information in a separate file
>   lib/stack: print base addresses on relocation setups
>   arm64: enable frame pointer and support stack unwinding
>   arm64: stack: update trace stack on exception
>   efi: print address of image
>   arm64: dump stack on bad exception
> 
>  .gitignore              |  1 +
>  Makefile                |  2 +-
>  arm/Makefile.arm        |  3 --
>  arm/Makefile.arm64      |  2 ++
>  arm/Makefile.common     |  8 +++++-
>  arm/cstart64.S          | 13 +++++++++
>  lib/arm64/asm-offsets.c |  6 +++-
>  lib/arm64/asm/stack.h   |  3 ++
>  lib/arm64/processor.c   |  1 +
>  lib/arm64/stack.c       | 62 +++++++++++++++++++++++++++++++++++++++++
>  lib/efi.c               |  4 +++
>  lib/stack.c             | 31 +++++++++++++++++++--
>  powerpc/Makefile.common |  1 +
>  x86/Makefile.common     |  5 +++-
>  14 files changed, 133 insertions(+), 9 deletions(-)
>  create mode 100644 lib/arm64/stack.c
> 
> -- 
> 2.34.1
>

Merged. arm64 backtraces will be really nice to have!

Thanks, Nadav!

drew