[PATCH 0/6] objtool: Add support for Arm64

Raphael Gault
2019-04-09T13:53:36Z

Hi,

As of now, objtool only supports the x86_64 architecture but the
groundwork has already been done in order to add support for other
architecture without too much effort.

This series of patches adds support for the arm64 architecture
based on the Armv8.5 Architecture Reference Manual.

* Patch 1 adapts the existing code to be able to add support for other
architecture.
* Patch 2 provide implementation of the required function for the arm64
architecture.
* Patch 3 adapts the checking of the stack state for the arm64
architecture.
* Patch 4 & 5 fix some warning objtool raised in some particular
functions of ~/arch/arm64/kernel/sleep.S. Patch 4 add a macro to
signal that some function should be ignored by objtool.
* Patch 6 enables stack validation for arm64.

Theses patches should provide support for the main cases and behaviour.
However a few corner cases are not yet handled by objtool:

* In the `~/arch/arm64/crypto/` directory, I noticed that some plain
data are sometimes stored in the `.text` section causing objtool to mistake
this for instructions and trying (and failing) to interprete them. If someone
could explain to me why we store data directly in the .text section I would
appreciate it.

* In the support for arm32 architecture such as in `~/arch/arm64/kernel/kuser32.S`
some A32 instructions are used but such instructions are not understood by
objtool causing a warning.

I also have a few unclear points I would like to bring to your
attention:

* For x86_64, when looking for a symbol relocation with explicit
addend, objtool systematically adds a +4 offset to the addend.
I don't understand why even if I have a feeling it is related
to the type of relacation.

* I currently don't have a clear understanding about how switch-tables
are generated on arm64 and how to retrieve them (based on relocations).

Please provide me with any feedback and comments as well on the content
than the style of these patches.

Thanks,

Raphael

->

Raphael Gault (6):
objtool: Refactor code to make it more suitable for multiple
architecture support
objtool: arm64: Add required implementation for supporting the aarch64
architecture in objtool.
objtool: arm64: Adapt the stack frame checks and the section analysis
for the arm architecture
arm64: assembler: Add macro to annotate asm function having non
standard stack-frame.
arm64: sleep: Add stack frame setup for __cpu_supsend_enter
objtool: arm64: Enable stack validation for arm64

arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/assembler.h | 18 +
arch/arm64/kernel/sleep.S | 4 +
tools/objtool/Build | 1 -
tools/objtool/arch.h | 11 +
tools/objtool/arch/arm64/Build | 6 +
tools/objtool/arch/arm64/bit_operations.c | 65 +
tools/objtool/arch/arm64/decode.c | 2870 +++++++++++++++++
.../objtool/arch/arm64/include/arch_special.h | 44 +
.../arch/arm64/include/asm/orc_types.h | 109 +
.../arch/arm64/include/bit_operations.h | 22 +
tools/objtool/arch/arm64/include/cfi.h | 76 +
.../objtool/arch/arm64/include/insn_decode.h | 219 ++
tools/objtool/arch/arm64/orc_gen.c | 40 +
tools/objtool/arch/x86/Build | 1 +
tools/objtool/arch/x86/decode.c | 111 +
tools/objtool/arch/x86/include/arch_special.h | 35 +
tools/objtool/{ => arch/x86/include}/cfi.h | 0
tools/objtool/{ => arch/x86}/orc_gen.c | 10 +-
tools/objtool/check.c | 209 +-
tools/objtool/check.h | 1 +
tools/objtool/elf.c | 3 +-
tools/objtool/orc.h | 4 +-
tools/objtool/special.c | 18 +-
24 files changed, 3740 insertions(+), 138 deletions(-)
create mode 100644 tools/objtool/arch/arm64/Build
create mode 100644 tools/objtool/arch/arm64/bit_operations.c
create mode 100644 tools/objtool/arch/arm64/decode.c
create mode 100644 tools/objtool/arch/arm64/include/arch_special.h
create mode 100644 tools/objtool/arch/arm64/include/asm/orc_types.h
create mode 100644 tools/objtool/arch/arm64/include/bit_operations.h
create mode 100644 tools/objtool/arch/arm64/include/cfi.h
create mode 100644 tools/objtool/arch/arm64/include/insn_decode.h
create mode 100644 tools/objtool/arch/arm64/orc_gen.c
create mode 100644 tools/objtool/arch/x86/include/arch_special.h
rename tools/objtool/{ => arch/x86/include}/cfi.h (100%)
rename tools/objtool/{ => arch/x86}/orc_gen.c (96%)

--
2.17.1