Re: [Crash-utility] [PATCH V2 1/2] RISC-V: Add arch_crash_save_vmcoreinfo support

On 18/10/2022 03:28, Xianting Tian wrote: > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > 在 2022/10/18 上午3:54, Conor Dooley 写道: > >> On Fri, Oct 14, 2022 at 09:41:38PM +0800, Xianting Tian wrote: >>> * 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&lt;xianting.tian(a)linux.alibaba.com&gt; >>> --- >>> 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)) { >> You've already got a #ifdef CONFIG_64BIT above, is there a reason why >> you'd use the IS_ENABLED here rather than merge this with the above >> section? I'm a big fan of IS_ENABLED but I'm not sure what it adds here, >> maybe you can show me the light :) > The IS_ENABLED() check prevents the line from getting executed, but > unlike an #ifdef it relies on it to be parsable. Hey Xianting, Firstly, neither this nor the other version of this message made it to the mailing list - and since I usually use lei to get my mails that is a bit of a problem :(

Yeah, I know that that is what IS_ENABLED() does, it's just in this situation it does not look very intentional & more like disjoint bits of copy-paste. It's fine though, leave it as it is.

Thanks, Conor. > I wrote this arch_crash_save_vmcoreinfo() func with reference to this: static void __init print_vm_layout(void) // arch/riscv/mm/init.c > { > pr_notice("Virtual kernel memory layout:\n"); > print_ml("fixmap", (unsigned long)FIXADDR_START, > (unsigned long)FIXADDR_TOP); > print_ml("pci io", (unsigned long)PCI_IO_START, > (unsigned long)PCI_IO_END); > print_ml("vmemmap", (unsigned long)VMEMMAP_START, > (unsigned long)VMEMMAP_END); > print_ml("vmalloc", (unsigned long)VMALLOC_START, > (unsigned long)VMALLOC_END); > #ifdef CONFIG_64BIT > print_ml("modules", (unsigned long)MODULES_VADDR, > (unsigned long)MODULES_END); > #endif > print_ml("lowmem", (unsigned long)PAGE_OFFSET, > (unsigned long)high_memory); > if (IS_ENABLED(CONFIG_64BIT)) { > #ifdef CONFIG_KASAN > print_ml("kasan", KASAN_SHADOW_START, KASAN_SHADOW_END); > #endif > > print_ml("kernel", (unsigned long)KERNEL_LINK_ADDR, > (unsigned long)ADDRESS_SPACE_END); > } > } > >> Thanks, >> Conor. >> >> >>> +#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); >>> + } >>> +} >>> -- >>> 2.17.1 >>> >>>