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* riscv: hibernate: remove WARN_ON in save_processor_stateSong Shuai2023-06-231-1/+0
| | | | | | | | | | | | | | | | | | | During hibernation or restoration, freeze_secondary_cpus checks num_online_cpus via BUG_ON, and the subsequent save_processor_state also does the checking with WARN_ON. In the case of CONFIG_PM_SLEEP_SMP=n, freeze_secondary_cpus is not defined, but the sole possible condition to disable CONFIG_PM_SLEEP_SMP is !SMP where num_online_cpus is always 1. We also don't have to check it in save_processor_state. So remove the unnecessary checking in save_processor_state. Fixes: c0317210012e ("RISC-V: Add arch functions to support hibernation/suspend-to-disk") Signed-off-by: Song Shuai <songshuaishuai@tinylab.org> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20230609075049.2651723-4-songshuaishuai@tinylab.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
* RISC-V: Add arch functions to support hibernation/suspend-to-diskSia Jee Heng2023-04-291-0/+427
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 specific hibernation header is implemented and is utilized by the arch_hibernation_header_restore() and arch_hibernation_header_save() functions. The arch specific hibernation header consists of satp, hartid, and the cpu_resume address. The kernel built version is also need to be 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. It 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_HIBERNATION - CONFIG_ARCH_HIBERNATION_HEADER - CONFIG_ARCH_HIBERNATION_POSSIBLE Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com> Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com> Reviewed-by: Mason Huo <mason.huo@starfivetech.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20230330064321.1008373-5-jeeheng.sia@starfivetech.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>