Re: [Crash-utility] [PATCH V4 1/2] RISC-V: Add arch_crash_save_vmcoreinfo support

在 2022/10/20 上午11:05, Baoquan He 写道: > On 10/20/22 at 10:17am, Xianting Tian wrote: >> 在 2022/10/20 上午10:08, Baoquan He 写道: >>> On 10/19/22 at 06:36pm, Xianting Tian wrote: >>>> Add arch_crash_save_vmcoreinfo(), which exports VM layout(MODULES, >>>> VMALLOC, >>>> VMEMMAP ranges and KERNEL_LINK_ADDR), 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(a)linux.alibaba.com&gt; >>>> --- >>>>    arch/riscv/kernel/Makefile     |  1 + >>>>    arch/riscv/kernel/crash_core.c | 23 +++++++++++++++++++++++ >>>>    2 files changed, 24 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..3e889d0ed7bd >>>> --- /dev/null >>>> +++ b/arch/riscv/kernel/crash_core.c >>>> @@ -0,0 +1,23 @@ >>>> +// 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)) >>>> + vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", >>>> KERNEL_LINK_ADDR); >>> Wondering why you don't put KERNEL_LINK_ADDR exporting into the above >>> ifdeffery scope, with that you can save one line of >>> "IS_ENABLED(CONFIG_64BIT)". >> I followed the rule in print_vm_layout() of arch/riscv/mm/init.c, >> which used >> IS_ENABLED when print the value of KERNEL_LINK_ADDR. >> > I see. There's PAGE_OFFSET in the middle. Thanks. > >          print_ml("lowmem", (unsigned long)PAGE_OFFSET, >                  (unsigned long)high_memory) > > So now, do you think if it's necessary to have another > IS_ENABLED(CONFIG_64BIT) in the current arch_crash_save_vmcoreinfo()? For which MACRO?  I think current code for PAGE_OFFSET is OK.