Messages in this thread | | | Date | Thu, 19 Jan 2023 08:39:20 +0530 | Subject | Re: [PATCH v15 1/7] crash: move crash_prepare_elf64_headers() | From | Sourabh Jain <> |
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On 12/01/23 22:53, Eric DeVolder wrote: > > > On 1/8/23 23:05, Sourabh Jain wrote: >> >> On 09/12/22 21:06, Eric DeVolder wrote: >>> At the outcome of this patch set, the crash_prepare_elf64_headers() >>> is utilized on both the kexec_file_load() and kexec_load() paths. As >>> such, need to move this function out of kexec_file.c and into a >>> common location crash_core.c. >>> >>> No functionality change. >>> >>> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> >>> Acked-by: Baoquan He <bhe@redhat.com> >>> --- >>> kernel/crash_core.c | 100 >>> ++++++++++++++++++++++++++++++++++++++++++++ >>> kernel/kexec_file.c | 99 ------------------------------------------- >>> 2 files changed, 100 insertions(+), 99 deletions(-) >>> >>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c >>> index a0eb4d5cf557..46c160d14045 100644 >>> --- a/kernel/crash_core.c >>> +++ b/kernel/crash_core.c >>> @@ -10,6 +10,7 @@ >>> #include <linux/utsname.h> >>> #include <linux/vmalloc.h> >>> #include <linux/sizes.h> >>> +#include <linux/kexec.h> >>> #include <asm/page.h> >>> #include <asm/sections.h> >>> @@ -314,6 +315,105 @@ static int __init parse_crashkernel_dummy(char >>> *arg) >>> } >>> early_param("crashkernel", parse_crashkernel_dummy); >>> +int crash_prepare_elf64_headers(struct crash_mem *mem, int >>> need_kernel_map, >>> + void **addr, unsigned long *sz) >>> +{ >>> + Elf64_Ehdr *ehdr; >>> + Elf64_Phdr *phdr; >>> + unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz; >>> + unsigned char *buf; >>> + unsigned int cpu, i; >>> + unsigned long long notes_addr; >>> + unsigned long mstart, mend; >>> + >>> + /* extra phdr for vmcoreinfo ELF note */ >>> + nr_phdr = nr_cpus + 1; >>> + nr_phdr += mem->nr_ranges; >>> + >>> + /* >>> + * kexec-tools creates an extra PT_LOAD phdr for kernel text >>> mapping >>> + * area (for example, ffffffff80000000 - ffffffffa0000000 on >>> x86_64). >>> + * I think this is required by tools like gdb. So same physical >>> + * memory will be mapped in two ELF headers. One will contain >>> kernel >>> + * text virtual addresses and other will have __va(physical) >>> addresses. >>> + */ >>> + >>> + nr_phdr++; >>> + elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr); >>> + elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN); >> Seems like above function is out of CONFIG_KEXEC_FILE but some of the >> structure/attributes like crash_mem and ELF_CORE_HEADER_ALIGN are >> still defined under CONFIG_KEXEC_FILE (look for include/linux/kexec.h). >> >> This leads to kernel build issue when CONFIG_KEXEC_FILE is disabled. >> >> Thanks, >> Sourabh Jain > > After looking into this for a bit, to allow hotplug without kexec_file > would require quite a bit of code movement. Why? Because hotplug is > basically built on top of (part of) the infrastructure that was needed > for kexec_file. > > I'd be inclined to suggest that KEXEC_FILE be a required dependency > for CRASH_HOTPLUG, ie:
Since kexec_load is deprecated I don't see any harm in doing that.
- Sourabh Jain
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