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

Hi Xianting, On 10/26/22 at 05:44pm, Xianting Tian wrote: > 在 2022/10/26 下午5:25, Conor Dooley 写道: >> 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. > I checked the KERNEL_LINK_ADDR definition of riscv,  it is valid for > CONFIG_64BIT and !CONFIG_64BIT. This series looks good to me. My only minor concern is if we can make the arch_crash_save_vmcoreinfo() as below. I don't understand why we have to have the CONFIG_64BIT ifdeffery and the IS_ENABLED(CONFIG_64BIT) between two adjacent code blocks. Not sure if we are saying the same thing.

+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); + vmcoreinfo_append_str("NUMBER(KERNEL_LINK_ADDR)=0x%lx\n", KERNEL_LINK_ADDR); +#endif +} > Maybe we can remove IS_ENABLED(CONFIG_64BIT) > > arch/riscv/include/asm/pgtable.h > #define ADDRESS_SPACE_END       (UL(-1)) > #ifdef CONFIG_64BIT > /* Leave 2GB for kernel and BPF at the end of the address space */ > #define KERNEL_LINK_ADDR        (ADDRESS_SPACE_END - SZ_2G + 1) > #else > #define KERNEL_LINK_ADDR        PAGE_OFFSET > #endif > > arch/riscv/include/asm/page.h > #ifdef CONFIG_64BIT > #ifdef CONFIG_MMU > #define PAGE_OFFSET             kernel_map.page_offset > #else > #define PAGE_OFFSET             _AC(CONFIG_PAGE_OFFSET, UL) > #endif > /* >  * By default, CONFIG_PAGE_OFFSET value corresponds to SV48 address space so >  * define the PAGE_OFFSET value for SV39. >  */ > #define PAGE_OFFSET_L4          _AC(0xffffaf8000000000, UL) > #define PAGE_OFFSET_L3          _AC(0xffffffd800000000, UL) > #else > #define PAGE_OFFSET             _AC(CONFIG_PAGE_OFFSET, UL) > #endif /* CONFIG_64BIT */ > >> 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. >>>>