m68k: Add kexec support (7d5f5fa2) · Commits · e / devices / android_kernel_fairphone_FP4

arch/m68k/Kconfig

+17 −0

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		@@ -87,6 +87,23 @@ config MMU_SUN3
		bool
		depends on MMU && !MMU_MOTOROLA && !MMU_COLDFIRE

		config KEXEC
		bool "kexec system call"
		depends on M68KCLASSIC
		help
		kexec is a system call that implements the ability to shutdown your
		current kernel, and to start another kernel. It is like a reboot
		but it is independent of the system firmware. And like a reboot
		you can start any kernel with it, not just Linux.

		The name comes from the similarity to the exec system call.

		It is an ongoing process to be certain the hardware in a machine
		is properly shutdown, so do not be surprised if this code does not
		initially work for you. As of this writing the exact hardware
		interface is strongly in flux, so no good recommendation can be
		made.

		menu "Platform setup"

		source arch/m68k/Kconfig.cpu

0 → 100644

+29 −0

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		#ifndef _ASM_M68K_KEXEC_H
		#define _ASM_M68K_KEXEC_H

		#ifdef CONFIG_KEXEC

		/* Maximum physical address we can use pages from */
		#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
		/* Maximum address we can reach in physical address mode */
		#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
		/* Maximum address we can use for the control code buffer */
		#define KEXEC_CONTROL_MEMORY_LIMIT (-1UL)

		#define KEXEC_CONTROL_PAGE_SIZE 4096

		#define KEXEC_ARCH KEXEC_ARCH_68K

		#ifndef __ASSEMBLY__

		static inline void crash_setup_regs(struct pt_regs *newregs,
		struct pt_regs *oldregs)
		{
		/* Dummy implementation for now */
		}

		#endif /* __ASSEMBLY__ */

		#endif /* CONFIG_KEXEC */

		#endif /* _ASM_M68K_KEXEC_H */

+2 −0

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		@@ -22,3 +22,5 @@ obj-$(CONFIG_PCI) += pcibios.o

		obj-$(CONFIG_HAS_DMA) += dma.o

		obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o

+3 −0

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		@@ -98,6 +98,9 @@ int main(void)
		DEFINE(CIABBASE, &ciab);
		DEFINE(C_PRA, offsetof(struct CIA, pra));
		DEFINE(ZTWOBASE, zTwoBase);

		/* enum m68k_fixup_type */
		DEFINE(M68K_FIXUP_MEMOFFSET, m68k_fixup_memoffset);
		#endif

		return 0;

0 → 100644

+58 −0

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		/*
		* machine_kexec.c - handle transition of Linux booting another kernel
		*/
		#include <linux/compiler.h>
		#include <linux/kexec.h>
		#include <linux/mm.h>
		#include <linux/delay.h>

		#include <asm/cacheflush.h>
		#include <asm/page.h>
		#include <asm/setup.h>

		extern const unsigned char relocate_new_kernel[];
		extern const size_t relocate_new_kernel_size;

		int machine_kexec_prepare(struct kimage *kimage)
		{
		return 0;
		}

		void machine_kexec_cleanup(struct kimage *kimage)
		{
		}

		void machine_shutdown(void)
		{
		}

		void machine_crash_shutdown(struct pt_regs *regs)
		{
		}

		typedef void (*relocate_kernel_t)(unsigned long ptr,
		unsigned long start,
		unsigned long cpu_mmu_flags) __noreturn;

		void machine_kexec(struct kimage *image)
		{
		void *reboot_code_buffer;
		unsigned long cpu_mmu_flags;

		reboot_code_buffer = page_address(image->control_code_page);

		memcpy(reboot_code_buffer, relocate_new_kernel,
		relocate_new_kernel_size);

		/*
		* we do not want to be bothered.
		*/
		local_irq_disable();

		pr_info("Will call new kernel at 0x%08lx. Bye...\n", image->start);
		__flush_cache_all();
		cpu_mmu_flags = m68k_cputype \| m68k_mmutype << 8;
		((relocate_kernel_t) reboot_code_buffer)(image->head & PAGE_MASK,
		image->start,
		cpu_mmu_flags);
		}