RE: [PATCH 0/3] RISC-V Hibernation Support

[JeeHeng Sia <jeeheng.sia@starfivetech.com>]

> -----Original Message-----
> From: Conor Dooley <conor@kernel.org>
> Sent: Friday, 6 January, 2023 5:38 PM
> To: JeeHeng Sia <jeeheng.sia@starfivetech.com>; paul.walmsley@sifive.com;
> palmer@dabbelt.com; aou@eecs.berkeley.edu
> Cc: linux-riscv@lists.infradead.org; linux-kernel@vger.kernel.org; JeeHeng Sia
> <jeeheng.sia@starfivetech.com>; Leyfoon Tan
> <leyfoon.tan@starfivetech.com>; Mason Huo
> <mason.huo@starfivetech.com>
> Subject: Re: [PATCH 0/3] RISC-V Hibernation Support
> 
> Hey folks,
> Just passing on some issues that automation picked up.
Thanks. Will submit a new patches series to address the issues.
> 
> 
> On 6 January 2023 06:05:32 GMT, Sia Jee Heng
> <jeeheng.sia@starfivetech.com> wrote:
> >This series adds RISC-V Hibernation/suspend to disk support.
> >Low level Arch functions were created to support hibernation.
> >swsusp_arch_suspend() relies code from __cpu_suspend_enter() to write
> >cpu state onto the stack, then calling swsusp_save() to save the memory
> >image.
> >
> >arch_hibernation_header_restore() and arch_hibernation_header_save()
> >functions are implemented to prevent kernel crash when resume,
> >the kernel built version is saved into the hibernation image header
> >to making sure only the same kernel is restore when resume.
> >
> >swsusp_arch_resume() creates a temporary page table that covering only
> >the linear map, copies the restore code to a 'safe' page, then start to
> >restore the memory image. Once completed, it restores the original
> >kernel's page table. It then calls into __hibernate_cpu_resume()
> >to restore the CPU context. Finally, it follows the normal hibernation
> >path back to the hibernation core.
> >
> >To enable hibernation/suspend to disk into RISCV, the below config
> >need to be enabled:
> >- CONFIG_ARCH_HIBERNATION_HEADER
> >- CONFIG_ARCH_HIBERNATION_POSSIBLE
> >
> >
> >At high-level, this series includes the following changes:
> >1) Change suspend_save_csrs() and suspend_restore_csrs()
> >   to public function as these functions are common to
> >   suspend/hibernation. (patch 1)
> >2) Enhance kernel_page_present() function to support huge page. (patch 2)
> >3) Add arch/riscv low level functions to support
> >   hibernation/suspend to disk. (patch 3)
> >
> >The above patches are based on kernel v6.2-rc2 and are tested on
> >Starfive VF2 SBC board.
> >
> >Sia Jee Heng (3):
> >  RISC-V: Change suspend_save_csrs and suspend_restore_csrs to public
> >    function
> >  RISC-V: mm: Enable huge page support to kernel_page_present() function
> 
> Unfortunately this breaks rv32_defconfig
> https://patchwork.kernel.org/project/linux-
> riscv/patch/20230106060535.104321-3-jeeheng.sia@starfivetech.com/
> 
> >  RISC-V: Add arch functions to support hibernation/suspend-to-disk
> 
> This one then breaks rv64 allmodconfig too :/
> 
> https://patchwork.kernel.org/project/linux-
> riscv/patch/20230106060535.104321-4-jeeheng.sia@starfivetech.com/
> 
> Thanks,
> Conor.
> 
> >
> > arch/riscv/Kconfig                |   7 +
> > arch/riscv/include/asm/suspend.h  |  23 ++
> > arch/riscv/kernel/Makefile        |   2 +-
> > arch/riscv/kernel/asm-offsets.c   |   5 +
> > arch/riscv/kernel/hibernate-asm.S | 123 +++++++++++
> > arch/riscv/kernel/hibernate.c     | 353 ++++++++++++++++++++++++++++++
> > arch/riscv/kernel/suspend.c       |   4 +-
> > arch/riscv/mm/pageattr.c          |   6 +
> > 8 files changed, 520 insertions(+), 3 deletions(-)
> > create mode 100644 arch/riscv/kernel/hibernate-asm.S
> > create mode 100644 arch/riscv/kernel/hibernate.c
> >
> >
> >base-commit: 1f5abbd77e2c1787e74b7c2caffac97def78ba52