powerpc: Support for relocatable kdump kernel (54622f10) · Commits · e / devices / android_kernel_fairphone_FP4

Documentation/kdump/kdump.txt

+11 −3

Original line number	Original line	Diff line number	Diff line
	@@ -109,7 +109,8 @@ There are two possible methods of using Kdump.
	2) Or use the system kernel binary itself as dump-capture kernel and there is		2) Or use the system kernel binary itself as dump-capture kernel and there is
	no need to build a separate dump-capture kernel. This is possible		no need to build a separate dump-capture kernel. This is possible
	only with the architecutres which support a relocatable kernel. As		only with the architecutres which support a relocatable kernel. As
	of today, i386, x86_64 and ia64 architectures support relocatable kernel.		of today, i386, x86_64, ppc64 and ia64 architectures support relocatable
			kernel.

	Building a relocatable kernel is advantageous from the point of view that		Building a relocatable kernel is advantageous from the point of view that
	one does not have to build a second kernel for capturing the dump. But		one does not have to build a second kernel for capturing the dump. But
	@@ -207,8 +208,15 @@ Dump-capture kernel config options (Arch Dependent, i386 and x86_64)
	Dump-capture kernel config options (Arch Dependent, ppc64)		Dump-capture kernel config options (Arch Dependent, ppc64)
	----------------------------------------------------------		----------------------------------------------------------

	* Make and install the kernel and its modules. DO NOT add this kernel		1) Enable "Build a kdump crash kernel" support under "Kernel" options:
	to the boot loader configuration files.
			CONFIG_CRASH_DUMP=y

			2) Enable "Build a relocatable kernel" support

			CONFIG_RELOCATABLE=y

			Make and install the kernel and its modules.

	Dump-capture kernel config options (Arch Dependent, ia64)		Dump-capture kernel config options (Arch Dependent, ia64)
	----------------------------------------------------------		----------------------------------------------------------

arch/powerpc/Kconfig

+3 −7

Original line number	Original line	Diff line number	Diff line
	@@ -323,13 +323,11 @@ config KEXEC

	config CRASH_DUMP		config CRASH_DUMP
	bool "Build a kdump crash kernel"		bool "Build a kdump crash kernel"
	depends on PPC_MULTIPLATFORM && PPC64		depends on PPC_MULTIPLATFORM && PPC64 && RELOCATABLE
	help		help
	Build a kernel suitable for use as a kdump capture kernel.		Build a kernel suitable for use as a kdump capture kernel.
	The kernel will be linked at a different address than normal, and		The same kernel binary can be used as production kernel and dump
	so can only be used for Kdump.		capture kernel.

	Don't change this unless you know what you are doing.

	config PHYP_DUMP		config PHYP_DUMP
	bool "Hypervisor-assisted dump (EXPERIMENTAL)"		bool "Hypervisor-assisted dump (EXPERIMENTAL)"
	@@ -829,11 +827,9 @@ config PAGE_OFFSET
	default "0xc000000000000000"		default "0xc000000000000000"
	config KERNEL_START		config KERNEL_START
	hex		hex
	default "0xc000000002000000" if CRASH_DUMP
	default "0xc000000000000000"		default "0xc000000000000000"
	config PHYSICAL_START		config PHYSICAL_START
	hex		hex
	default "0x02000000" if CRASH_DUMP
	default "0x00000000"		default "0x00000000"
	endif		endif

arch/powerpc/include/asm/kdump.h

+12 −5

Original line number	Original line	Diff line number	Diff line
	@@ -9,6 +9,12 @@
	* Reserve to the end of the FWNMI area, see head_64.S */		* Reserve to the end of the FWNMI area, see head_64.S */
	#define KDUMP_RESERVE_LIMIT 0x10000 /* 64K */		#define KDUMP_RESERVE_LIMIT 0x10000 /* 64K */

			/*
			* Used to differentiate between relocatable kdump kernel and other
			* kernels
			*/
			#define KDUMP_SIGNATURE 0xfeed1234

	#ifdef CONFIG_CRASH_DUMP		#ifdef CONFIG_CRASH_DUMP

	#define KDUMP_TRAMPOLINE_START 0x0100		#define KDUMP_TRAMPOLINE_START 0x0100
	@@ -19,17 +25,18 @@
	#endif /* CONFIG_CRASH_DUMP */		#endif /* CONFIG_CRASH_DUMP */

	#ifndef __ASSEMBLY__		#ifndef __ASSEMBLY__
	#ifdef CONFIG_CRASH_DUMP

			extern unsigned long __kdump_flag;

			#if defined(CONFIG_CRASH_DUMP) && !defined(CONFIG_RELOCATABLE)
	extern void reserve_kdump_trampoline(void);		extern void reserve_kdump_trampoline(void);
	extern void setup_kdump_trampoline(void);		extern void setup_kdump_trampoline(void);
			#else
	#else /* !CONFIG_CRASH_DUMP */		/* !CRASH_DUMP \|\| RELOCATABLE */

	static inline void reserve_kdump_trampoline(void) { ; }		static inline void reserve_kdump_trampoline(void) { ; }
	static inline void setup_kdump_trampoline(void) { ; }		static inline void setup_kdump_trampoline(void) { ; }
			#endif

	#endif /* CONFIG_CRASH_DUMP */
	#endif /* __ASSEMBLY__ */		#endif /* __ASSEMBLY__ */

	#endif /* __PPC64_KDUMP_H */		#endif /* __PPC64_KDUMP_H */

arch/powerpc/kernel/crash_dump.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -30,6 +30,7 @@
	/* Stores the physical address of elf header of crash image. */		/* Stores the physical address of elf header of crash image. */
	unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;		unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;

			#ifndef CONFIG_RELOCATABLE
	void __init reserve_kdump_trampoline(void)		void __init reserve_kdump_trampoline(void)
	{		{
	lmb_reserve(0, KDUMP_RESERVE_LIMIT);		lmb_reserve(0, KDUMP_RESERVE_LIMIT);
	@@ -68,6 +69,7 @@ void __init setup_kdump_trampoline(void)

	DBG(" <- setup_kdump_trampoline()\n");		DBG(" <- setup_kdump_trampoline()\n");
	}		}
			#endif /* CONFIG_RELOCATABLE */

	/*		/*
	* Note: elfcorehdr_addr is not just limited to vmcore. It is also used by		* Note: elfcorehdr_addr is not just limited to vmcore. It is also used by

arch/powerpc/kernel/head_64.S

+33 −6

Original line number	Original line	Diff line number	Diff line
	@@ -97,6 +97,12 @@ __secondary_hold_spinloop:
	__secondary_hold_acknowledge:		__secondary_hold_acknowledge:
	.llong 0x0		.llong 0x0

			/* This flag is set by purgatory if we should be a kdump kernel. */
			/* Do not move this variable as purgatory knows about it. */
			.globl __kdump_flag
			__kdump_flag:
			.llong 0x0

	#ifdef CONFIG_PPC_ISERIES		#ifdef CONFIG_PPC_ISERIES
	/*		/*
	* At offset 0x20, there is a pointer to iSeries LPAR data.		* At offset 0x20, there is a pointer to iSeries LPAR data.
	@@ -1384,7 +1390,13 @@ _STATIC(__after_prom_start)
	/* process relocations for the final address of the kernel */		/* process relocations for the final address of the kernel */
	lis r25,PAGE_OFFSET@highest /* compute virtual base of kernel */		lis r25,PAGE_OFFSET@highest /* compute virtual base of kernel */
	sldi r25,r25,32		sldi r25,r25,32
	mr r3,r25		#ifdef CONFIG_CRASH_DUMP
			ld r7,__kdump_flag-_stext(r26)
			cmpldi cr0,r7,1 /* kdump kernel ? - stay where we are */
			bne 1f
			add r25,r25,r26
			#endif
			1: mr r3,r25
	bl .relocate		bl .relocate
	#endif		#endif

	@@ -1398,11 +1410,26 @@ _STATIC(__after_prom_start)
	li r3,0 /* target addr */		li r3,0 /* target addr */
	mr. r4,r26 /* In some cases the loader may */		mr. r4,r26 /* In some cases the loader may */
	beq 9f /* have already put us at zero */		beq 9f /* have already put us at zero */
	lis r5,(copy_to_here - _stext)@ha
	addi r5,r5,(copy_to_here - _stext)@l /* # bytes of memory to copy */
	li r6,0x100 /* Start offset, the first 0x100 */		li r6,0x100 /* Start offset, the first 0x100 */
	/* bytes were copied earlier. */		/* bytes were copied earlier. */

			#ifdef CONFIG_CRASH_DUMP
			/*
			* Check if the kernel has to be running as relocatable kernel based on the
			* variable __kdump_flag, if it is set the kernel is treated as relocatable
			* kernel, otherwise it will be moved to PHYSICAL_START
			*/
			ld r7,__kdump_flag-_stext(r26)
			cmpldi cr0,r7,1
			bne 3f

			li r5,__end_interrupts - _stext /* just copy interrupts */
			b 5f
			3:
			#endif
			lis r5,(copy_to_here - _stext)@ha
			addi r5,r5,(copy_to_here - _stext)@l /* # bytes of memory to copy */

	bl .copy_and_flush /* copy the first n bytes */		bl .copy_and_flush /* copy the first n bytes */
	/* this includes the code being */		/* this includes the code being */
	/* executed here. */		/* executed here. */
	@@ -1411,15 +1438,15 @@ _STATIC(__after_prom_start)
	mtctr r8		mtctr r8
	bctr		bctr

			p_end: .llong _end - _stext

	4: /* Now copy the rest of the kernel up to _end */		4: /* Now copy the rest of the kernel up to _end */
	addis r5,r26,(p_end - _stext)@ha		addis r5,r26,(p_end - _stext)@ha
	ld r5,(p_end - _stext)@l(r5) /* get _end */		ld r5,(p_end - _stext)@l(r5) /* get _end */
	bl .copy_and_flush /* copy the rest */		5: bl .copy_and_flush /* copy the rest */

	9: b .start_here_multiplatform		9: b .start_here_multiplatform

	p_end: .llong _end - _stext

	/*		/*
	* Copy routine used to copy the kernel to start at physical address 0		* Copy routine used to copy the kernel to start at physical address 0
	* and flush and invalidate the caches as needed.		* and flush and invalidate the caches as needed.