RISC-V With Linux 6.4 Adds Hibernation / Suspend-To-Disk Support

One of the missing RISC-V features now in place for the in-development Linux 6.4 kernel is system hibernation / suspend-to-disk support.

In development the past number of months and going through a number of rounds of review is RISC-V hibernation/suspend-to-disk support. From the earlier patch series:

"To enable hibernation/suspend to disk into RISCV, the below config need to be enabled:

- CONFIG_HIBERNATION
- 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.
2) Refactor the common code in the __cpu_resume_enter() function and __hibernate_cpu_resume() function. The common code are used by hibernation and suspend.
3) Enhance kernel_page_present() function to support huge page.
4) Add arch/riscv low level functions to support hibernation/suspend to disk.

The above patches are based on kernel v6.3-rc4 and have been tested on StarFive VF2 SBC board and Qemu (using raw disk format). ACPI platform mode is not supported in this series."

The RISC-V hibernation support in turn was submitted on Friday as part of additional RISC-V patches for Linux 6.4.