Re: [PATCH V3 1/2] RISC-V: Add arch_crash_save_vmcoreinfo support

Xianting Tian
2022-10-18T09:25:44Z

在 2022/10/18 下午5:10, Baoquan He 写道:
> On 10/18/22 at 04:17pm, Xianting Tian wrote:
>> 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>
>> ---
>> arch/riscv/kernel/Makefile | 1 +
>> arch/riscv/kernel/crash_core.c | 29 +++++++++++++++++++++++++++++
>> 2 files changed, 30 insertions(+)
>> create mode 100644 arch/riscv/kernel/crash_core.c
>>
>> diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
>> index db6e4b1294ba..4cf303a779ab 100644
>> --- a/arch/riscv/kernel/Makefile
>> +++ b/arch/riscv/kernel/Makefile
>> @@ -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
>>
>> diff --git a/arch/riscv/kernel/crash_core.c b/arch/riscv/kernel/crash_core.c
>> new file mode 100644
>> index 000000000000..8d7f5ff108da
>> --- /dev/null
>> +++ b/arch/riscv/kernel/crash_core.c
>> @@ -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);
> Seems this is the firsr ARCH where kasan and kernel link/bpf space are
> added to dump and analyze. Just curious, have you got code change to
> make use of them to do dumping and analyze?

KASAN_SHADOW_START is not used, KERNEL_LINK_ADDR is used in the crash patch set:
https://patchwork.kernel.org/project/linux-riscv/cover/20220813031753.3097720-1-xianting.tian@linux.alibaba.com/

I add it in case of using in furture.

>
> Thanks
> Baoquan