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

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()?