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

Message

Björn Töpel April 9, 2025, 8:14 p.m. UTC

From: Björn Töpel <[e-mail]>

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/[e-mail]/
[2] https://github.com/riscv-collab/kexec-tools.git
[3] https://lore.kernel.org/linux-riscv/[e-mail]/
[4] https://lore.kernel.org/linux-riscv/[e-mail]/
[5] https://lore.kernel.org/linux-riscv/[e-mail]/

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

Comments

Simon Horman April 14, 2025, 8:40 a.m. UTC | #1

On Wed, Apr 09, 2025 at 10:14:22PM +0200, Björn Töpel wrote:
> From: Björn Töpel <[e-mail]>
> 
> 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.

Thanks Björn,

I haven't looked over the patches yet.
But in principle I agree with this approach.

> 
> 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

...