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RISC-V: Add arch_crash_save_vmcoreinfo support
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Add arch_crash_save_vmcoreinfo(), which exports VM layout(MODULES, VMALLOC,
VMEMMAP and KERNEL_LINK_ADDR ranges), va bits and ram base for vmcore.

Default pagetable levels and PAGE_OFFSET aren't same for different kernel
version as below. For pagetable levels, it sets sv57 by default and falls
back to setting sv48 at boot time if sv57 is not supported by the hardware.

For ram base, the default value is 0x80200000 for qemu riscv64 env and,
for example, is 0x200000 on the XuanTie 910 CPU.

 * Linux Kernel 5.18 ~
 *      PGTABLE_LEVELS = 5
 *      PAGE_OFFSET = 0xff60000000000000
 * Linux Kernel 5.17 ~
 *      PGTABLE_LEVELS = 4
 *      PAGE_OFFSET = 0xffffaf8000000000
 * Linux Kernel 4.19 ~
 *      PGTABLE_LEVELS = 3
 *      PAGE_OFFSET = 0xffffffe000000000

Since these configurations change from time to time and version to version,
it is preferable to export them via vmcoreinfo than to change the crash's
code frequently, it can simplify the development of crash tool.

Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
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Xianting Tian authored and intel-lab-lkp committed Oct 18, 2022
1 parent 1eb303d commit 6819816
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1 change: 1 addition & 0 deletions arch/riscv/kernel/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,7 @@ obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_KEXEC_CORE) += kexec_relocate.o crash_save_regs.o machine_kexec.o
obj-$(CONFIG_KEXEC_FILE) += elf_kexec.o machine_kexec_file.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_CRASH_CORE) += crash_core.o

obj-$(CONFIG_JUMP_LABEL) += jump_label.o

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29 changes: 29 additions & 0 deletions arch/riscv/kernel/crash_core.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,29 @@
// SPDX-License-Identifier: GPL-2.0-only

#include <linux/crash_core.h>
#include <linux/pagemap.h>

void arch_crash_save_vmcoreinfo(void)
{
VMCOREINFO_NUMBER(VA_BITS);
VMCOREINFO_NUMBER(phys_ram_base);

vmcoreinfo_append_str("NUMBER(PAGE_OFFSET)=0x%lx\n", PAGE_OFFSET);
vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START);
vmcoreinfo_append_str("NUMBER(VMALLOC_END)=0x%lx\n", VMALLOC_END);
vmcoreinfo_append_str("NUMBER(VMEMMAP_START)=0x%lx\n", VMEMMAP_START);
vmcoreinfo_append_str("NUMBER(VMEMMAP_END)=0x%lx\n", VMEMMAP_END);
#ifdef CONFIG_64BIT
vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", MODULES_VADDR);
vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", MODULES_END);
#endif

if (IS_ENABLED(CONFIG_64BIT)) {
#ifdef CONFIG_KASAN
vmcoreinfo_append_str("NUMBER(KASAN_SHADOW_START)=0x%lx\n", KASAN_SHADOW_START);
vmcoreinfo_append_str("NUMBER(KASAN_SHADOW_END)=0x%lx\n", KASAN_SHADOW_END);
#endif
vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", KERNEL_LINK_ADDR);
vmcoreinfo_append_str("NUMBER(ADDRESS_SPACE_END)=0x%lx\n", ADDRESS_SPACE_END);
}
}

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