[PATCH v2 1/2] LoongArch: kdump: Add single kernel image implementation

[Youling Tang]

This feature depends on the kernel being relocatable.

Enable using single kernel image for kdump, and then no longer need to build
two kernels (production kernel and capture kernel share single kernel image).

Also enable CONFIG_CRASH_DUMP in loongson3_defconfig.

Signed-off-by: Youling Tang <tangyouling@xxxxxxxxxxx>
---
 arch/loongarch/Kconfig                     | 12 +-----------
 arch/loongarch/Makefile                    |  4 ----
 arch/loongarch/configs/loongson3_defconfig |  1 +
 arch/loongarch/include/asm/addrspace.h     |  2 ++
 arch/loongarch/kernel/head.S               |  2 +-
 5 files changed, 5 insertions(+), 16 deletions(-)

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index bafdfc8c7a4d..7342a36e8a15 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -513,6 +513,7 @@ config KEXEC
 
 config CRASH_DUMP
 	bool "Build kdump crash kernel"
+	select RELOCATABLE
 	help
 	  Generate crash dump after being started by kexec. This should
 	  be normally only set in special crash dump kernels which are
@@ -522,17 +523,6 @@ config CRASH_DUMP
 
 	  For more details see Documentation/admin-guide/kdump/kdump.rst
 
-config PHYSICAL_START
-	hex "Physical address where the kernel is loaded"
-	default "0x90000000a0000000"
-	depends on CRASH_DUMP
-	help
-	  This gives the XKPRANGE address where the kernel is loaded.
-	  If you plan to use kernel for capturing the crash dump change
-	  this value to start of the reserved region (the "X" value as
-	  specified in the "crashkernel=YM@XM" command line boot parameter
-	  passed to the panic-ed kernel).
-
 config RELOCATABLE
 	bool "Relocatable kernel"
 	help
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index 768592998b39..f71edf574101 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -79,11 +79,7 @@ endif
 cflags-y += -ffreestanding
 cflags-y += $(call cc-option, -mno-check-zero-division)
 
-ifndef CONFIG_PHYSICAL_START
 load-y		= 0x9000000000200000
-else
-load-y		= $(CONFIG_PHYSICAL_START)
-endif
 bootvars-y	= VMLINUX_LOAD_ADDRESS=$(load-y)
 
 drivers-$(CONFIG_PCI)		+= arch/loongarch/pci/
diff --git a/arch/loongarch/configs/loongson3_defconfig b/arch/loongarch/configs/loongson3_defconfig
index cb52774c80e8..7885f6e5de93 100644
--- a/arch/loongarch/configs/loongson3_defconfig
+++ b/arch/loongarch/configs/loongson3_defconfig
@@ -48,6 +48,7 @@ CONFIG_HOTPLUG_CPU=y
 CONFIG_NR_CPUS=64
 CONFIG_NUMA=y
 CONFIG_KEXEC=y
+CONFIG_CRASH_DUMP=y
 CONFIG_SUSPEND=y
 CONFIG_HIBERNATION=y
 CONFIG_ACPI=y
diff --git a/arch/loongarch/include/asm/addrspace.h b/arch/loongarch/include/asm/addrspace.h
index d342935e5a72..4edcb3c21cf5 100644
--- a/arch/loongarch/include/asm/addrspace.h
+++ b/arch/loongarch/include/asm/addrspace.h
@@ -125,4 +125,6 @@ extern unsigned long vm_map_base;
 #define ISA_IOSIZE	SZ_16K
 #define IO_SPACE_LIMIT	(PCI_IOSIZE - 1)
 
+#define PHYS_LINK_ADDR	PHYSADDR(VMLINUX_LOAD_ADDRESS)
+
 #endif /* _ASM_ADDRSPACE_H */
diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S
index 1d35becc01ee..7fb32aa26c2c 100644
--- a/arch/loongarch/kernel/head.S
+++ b/arch/loongarch/kernel/head.S
@@ -24,7 +24,7 @@ _head:
 	.org	0x8
 	.dword	kernel_entry		/* Kernel entry point */
 	.dword	_end - _text		/* Kernel image effective size */
-	.quad	0			/* Kernel image load offset from start of RAM */
+	.quad	PHYS_LINK_ADDR		/* Kernel image load offset from start of RAM */
 	.org	0x38			/* 0x20 ~ 0x37 reserved */
 	.long	LINUX_PE_MAGIC
 	.long	pe_header - _head	/* Offset to the PE header */
-- 
2.37.3