Add single kernel image implementation for kdump.
kexec-tools needs to be updated to make sure it jumps to the correct
kernel entry.
When kaslr is enabled, it is best to add the "nokaslr" parameter when
performing kdump operations to ensure that the randomized kernel
position conflicts with other segments (such as initrd loading
position).
eg: sudo kexec -p vmlinux.efi --reuse-cmdline --append="nokaslr"
Changes from v1 to v2:
- Rewrite commit message.
Youling Tang (2):
LoongArch: kdump: Add single kernel image implementation
LoongArch: kdump: Add crashkernel=YM handling
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 +-
arch/loongarch/kernel/setup.c | 15 ++++++++++++---
6 files changed, 17 insertions(+), 19 deletions(-)
--
2.37.3
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 <[email protected]>
---
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
When the kernel crashkernel parameter is specified with just a size,
we are supposed to allocate a region from RAM to store the crashkernel,
"crashkernel=512M" would be recommended for kdump.
Fix this by lifting similar code from x86, importing it to LoongArch
with the LoongArch specific parameters added. We allocate the crashkernel
region from the first 4G of physical memory (SWIOTLB needs to be allocated
on low 4G). Currently LoongArch does not implement crashkernel_low and
crashkernel_high like x86.
When X is not specified, crash_base defaults to 0 (crashkernel=YM@XM).
Signed-off-by: Youling Tang <[email protected]>
---
arch/loongarch/kernel/setup.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index 4344502c0b31..ac2aad988fdb 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -234,11 +234,14 @@ static void __init arch_reserve_vmcore(void)
#endif
}
+/* 16M alignment for crash kernel regions */
+#define CRASH_ALIGN SZ_16M
+#define CRASH_ADDR_MAX SZ_4G
+
static void __init arch_parse_crashkernel(void)
{
#ifdef CONFIG_KEXEC
int ret;
- unsigned long long start;
unsigned long long total_mem;
unsigned long long crash_base, crash_size;
@@ -247,8 +250,14 @@ static void __init arch_parse_crashkernel(void)
if (ret < 0 || crash_size <= 0)
return;
- start = memblock_phys_alloc_range(crash_size, 1, crash_base, crash_base + crash_size);
- if (start != crash_base) {
+ if (crash_base <= 0) {
+ crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, CRASH_ALIGN,
+ CRASH_ADDR_MAX);
+ if (!crash_base) {
+ pr_warn("crashkernel reservation failed - No suitable area found.\n");
+ return;
+ }
+ } else if (!memblock_phys_alloc_range(crash_size, 1, crash_base, crash_base + crash_size)) {
pr_warn("Invalid memory region reserved for crash kernel\n");
return;
}
--
2.37.3