Unverified Commit c0317210 authored by Sia Jee Heng's avatar Sia Jee Heng Committed by Palmer Dabbelt
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RISC-V: Add arch functions to support hibernation/suspend-to-disk 



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: default avatarSia Jee Heng <jeeheng.sia@starfivetech.com>
Reviewed-by: default avatarLey Foon Tan <leyfoon.tan@starfivetech.com>
Reviewed-by: default avatarMason Huo <mason.huo@starfivetech.com>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230330064321.1008373-5-jeeheng.sia@starfivetech.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent a15c90b6

arch/riscv/Kconfig

+7 −1
Original line number Diff line number Diff line
@@ -54,7 +54,7 @@ config RISCV 
	select CLINT_TIMER if !MMU

	select CLONE_BACKWARDS

	select COMMON_CLK

	select CPU_PM if CPU_IDLE

	select CPU_PM if CPU_IDLE || HIBERNATION

	select EDAC_SUPPORT

	select GENERIC_ARCH_TOPOLOGY

	select GENERIC_ATOMIC64 if !64BIT
@@ -707,6 +707,12 @@ menu "Power management options" 


source "kernel/power/Kconfig"



config ARCH_HIBERNATION_POSSIBLE

	def_bool y



config ARCH_HIBERNATION_HEADER

	def_bool HIBERNATION



endmenu # "Power management options"



menu "CPU Power Management"

arch/riscv/include/asm/assembler.h

+20 −0
Original line number Diff line number Diff line
@@ -59,4 +59,24 @@ 
		REG_L	s11, (SUSPEND_CONTEXT_REGS + PT_S11)(a0)

	.endm



/*

 * copy_page - copy 1 page (4KB) of data from source to destination

 * @a0 - destination

 * @a1 - source

 */

	.macro	copy_page a0, a1

		lui	a2, 0x1

		add	a2, a2, a0

1 :

		REG_L	t0, 0(a1)

		REG_L	t1, SZREG(a1)



		REG_S	t0, 0(a0)

		REG_S	t1, SZREG(a0)



		addi	a0, a0, 2 * SZREG

		addi	a1, a1, 2 * SZREG

		bne	a2, a0, 1b

	.endm



#endif	/* __ASM_ASSEMBLER_H */

arch/riscv/include/asm/suspend.h

+19 −0
Original line number Diff line number Diff line
@@ -21,6 +21,11 @@ struct suspend_context { 
#endif

};



/*

 * Used by hibernation core and cleared during resume sequence

 */

extern int in_suspend;



/* Low-level CPU suspend entry function */

int __cpu_suspend_enter(struct suspend_context *context);
@@ -36,4 +41,18 @@ int __cpu_resume_enter(unsigned long hartid, unsigned long context); 
/* Used to save and restore the CSRs */

void suspend_save_csrs(struct suspend_context *context);

void suspend_restore_csrs(struct suspend_context *context);



/* Low-level API to support hibernation */

int swsusp_arch_suspend(void);

int swsusp_arch_resume(void);

int arch_hibernation_header_save(void *addr, unsigned int max_size);

int arch_hibernation_header_restore(void *addr);

int __hibernate_cpu_resume(void);



/* Used to resume on the CPU we hibernated on */

int hibernate_resume_nonboot_cpu_disable(void);



asmlinkage void hibernate_restore_image(unsigned long resume_satp, unsigned long satp_temp,

					unsigned long cpu_resume);

asmlinkage int hibernate_core_restore_code(void);

#endif

arch/riscv/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ obj-$(CONFIG_MODULES) += module.o 
obj-$(CONFIG_MODULE_SECTIONS)	+= module-sections.o



obj-$(CONFIG_CPU_PM)		+= suspend_entry.o suspend.o

obj-$(CONFIG_HIBERNATION)	+= hibernate.o hibernate-asm.o



obj-$(CONFIG_FUNCTION_TRACER)	+= mcount.o ftrace.o

obj-$(CONFIG_DYNAMIC_FTRACE)	+= mcount-dyn.o

arch/riscv/kernel/asm-offsets.c

+5 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/kbuild.h>

#include <linux/mm.h>

#include <linux/sched.h>

#include <linux/suspend.h>

#include <asm/kvm_host.h>

#include <asm/thread_info.h>

#include <asm/ptrace.h>
@@ -116,6 +117,10 @@ void asm_offsets(void) 


	OFFSET(SUSPEND_CONTEXT_REGS, suspend_context, regs);



	OFFSET(HIBERN_PBE_ADDR, pbe, address);

	OFFSET(HIBERN_PBE_ORIG, pbe, orig_address);

	OFFSET(HIBERN_PBE_NEXT, pbe, next);



	OFFSET(KVM_ARCH_GUEST_ZERO, kvm_vcpu_arch, guest_context.zero);

	OFFSET(KVM_ARCH_GUEST_RA, kvm_vcpu_arch, guest_context.ra);

	OFFSET(KVM_ARCH_GUEST_SP, kvm_vcpu_arch, guest_context.sp);