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

On Wed, Oct 26, 2022 at 05:08:11PM +0800, Xianting Tian wrote: > Hi Palmer, Conor > > Is this version OK for you? The weird ifdef/IS_ENABLED thing was the only comment I had. It's a bit odd & I notice Baoquan brought it up too. I didn't (and won't) give you a reviewed by on these patches because I don't understand the area well enough. The general nitpickery seems to be sorted though.

Thanks, Conor. > 在 2022/10/20 下午12:40, Xianting Tian 写道: >> 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. >>