[PATCH 0/4] kexec-tools RISC-V port

Björn Töpel
2025-04-09T20:14:56Z

From: Björn Töpel <bjorn@rivosinc.com>

Hi!

This is an attempt to finally get the RISC-V patches for kexec-tools
upstream.

Simon suggested in [1] that:

> In my mind the big question is how to move RISC-V support from that
> branch, to being merged into main.
>
> IIRC there were some issues that needed to be addressed. Perhaps they
> are all addressed by this series, and with some appropriate squashing
> we can move forwards with a series based on main?

I talked to Nick last week, and he suggested that we'd work the RISC-V
collab Github [2], but I think it's just easier to do it on the list.

I've been collecting a number of different trees out there, and tried
to group them in a series.

Given that there is not support for RISC-V upstream yet, I didn't see
the need to carry all the fixes/updates ("development history") as
separate commits -- it doesn't help bugtracking/bisectability.

Instead the first commit message is a big one, and tries to give
attribution to all involved parties. Input/thoughts are very much
welcome!

To properly test this on RISC-V, the upstream Linux kernel has most
things in 6.15-rc1, e.g.:
commit 28093cfef5dd ("riscv/kexec_file: Handle R_RISCV_64 in purgatory relocator")
commit 3f7023171df4 ("riscv/purgatory: 4B align purgatory_start")

To cross-build kexec-tools:
| ./bootstrap
| ./configure --host=riscv64-linux-gnu
| make

For some tests, additional kernel patches are needed, that as of today
is not in 6.15-rc1:
* To test "kexec -s -l Image", kexec_file_load with Image support is
needed [3]
* To test "kexec -c -l vmlinux" with CONFIG_RELOCATABLE, a kbuild fix
is needed [4]
* Typically if you load initrd, or a large kernel [5] (since a bunch
of Reserved regions are not properly exposed).

I've tested combinations with crashkernel (-p), and regular (-c/-s + -e) for:
* ACPI/UEFI
* DT/UEFI
* DT
* w/ initrd
* w/o initrd
* ELF (userland loader + kexec_load, and kexec_file_load)
* Image (userland loader + kexec_load, and kexec_file_load)

I'm sure there are combinations I've missed, but at least from my POV
we're in a pretty good shape.

All authors: Please let me know if you prefer another split of the
patches. Or something else for that matter! ;-)

Let's get the ball rolling!
Björn

[1] https://lore.kernel.org/kexec/20230920115634.GG224399@kernel.org/
[2] https://github.com/riscv-collab/kexec-tools.git
[3] https://lore.kernel.org/linux-riscv/20250409193004.643839-1-bjorn@kernel.org/
[4] https://lore.kernel.org/linux-riscv/20250408072851.90275-1-alexghiti@rivosinc.com/
[5] https://lore.kernel.org/linux-riscv/20250409182129.634415-1-bjorn@kernel.org/

Li Zhengyu (1):
RISC-V: Enable kexec_file_load syscall

Nick Kossifidis (1):
RISC-V: Add support for riscv kexec/kdump on kexec-tools

Song Shuai (2):
RISC-V: Separate elf_riscv_find_pbase out
RISC-V: Support loading Image binary file

configure.ac | 3 +
include/elf.h | 1 +
kexec/Makefile | 1 +
kexec/arch/riscv/Makefile | 37 ++
kexec/arch/riscv/crashdump-riscv.c | 140 +++++++
kexec/arch/riscv/image-header.h | 88 ++++
kexec/arch/riscv/include/arch/options.h | 43 ++
kexec/arch/riscv/iomem.h | 10 +
kexec/arch/riscv/kexec-elf-riscv.c | 184 +++++++++
kexec/arch/riscv/kexec-image-riscv.c | 95 +++++
kexec/arch/riscv/kexec-riscv.c | 526 ++++++++++++++++++++++++
kexec/arch/riscv/kexec-riscv.h | 53 +++
kexec/dt-ops.c | 442 +++++++++++++++++++-
kexec/dt-ops.h | 7 +
kexec/kexec-syscall.h | 7 +
purgatory/Makefile | 1 +
purgatory/arch/riscv/Makefile | 7 +
17 files changed, 1644 insertions(+), 1 deletion(-)
create mode 100644 kexec/arch/riscv/Makefile
create mode 100644 kexec/arch/riscv/crashdump-riscv.c
create mode 100644 kexec/arch/riscv/image-header.h
create mode 100644 kexec/arch/riscv/include/arch/options.h
create mode 100644 kexec/arch/riscv/iomem.h
create mode 100644 kexec/arch/riscv/kexec-elf-riscv.c
create mode 100644 kexec/arch/riscv/kexec-image-riscv.c
create mode 100644 kexec/arch/riscv/kexec-riscv.c
create mode 100644 kexec/arch/riscv/kexec-riscv.h
create mode 100644 purgatory/arch/riscv/Makefile

base-commit: a7fcd424c4c80dea5a2fd5ffa274ffeb8129c790