Re: [PATCH v17 06/10] riscv: kexec_file: Use crash_prepare_headers() helper to simplify code

On Mon, Jun 29, 2026 at 5:48 PM Jinjie Ruan <[email protected]> wrote:
>
> Use the newly introduced crash_prepare_headers() function to replace
> the existing prepare_elf_headers(), allocate cmem and exclude crash kernel
> memory in the crash core, which reduce code duplication.
>
> Only the following two architecture functions need to be implemented:
> - arch_get_system_nr_ranges(). Call get_nr_ram_ranges_callback()
>   to pre-counts the max number of memory ranges.
>
> - arch_crash_populate_cmem(). Use prepare_elf64_ram_headers_callback()
>   to collects the memory ranges and fills them into cmem.
>
> Cc: Paul Walmsley <[email protected]>
> Cc: Palmer Dabbelt <[email protected]>
> Cc: Albert Ou <[email protected]>
> Cc: Alexandre Ghiti <[email protected]>
> Cc: Guo Ren <[email protected]>
> Reviewed-by: Sourabh Jain <[email protected]>
> Acked-by: Baoquan He <[email protected]>
> Acked-by: Mike Rapoport (Microsoft) <[email protected]>
> Signed-off-by: Jinjie Ruan <[email protected]>
> ---
>  arch/riscv/kernel/machine_kexec_file.c | 47 +++++++-------------------
>  1 file changed, 12 insertions(+), 35 deletions(-)
>
> diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
> index fa2946aa9b8f..1dfb1d9eb691 100644
> --- a/arch/riscv/kernel/machine_kexec_file.c
> +++ b/arch/riscv/kernel/machine_kexec_file.c
> @@ -45,6 +45,15 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
>         return 0;
>  }
>
> +unsigned int arch_get_system_nr_ranges(void)
> +{
> +       unsigned int nr_ranges = 2; /* For exclusion of crashkernel region */
> +
> +       walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
> +
> +       return nr_ranges;
> +}
> +
>  static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
>  {
>         struct crash_mem *cmem = arg;
> @@ -56,41 +65,9 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
>         return 0;
>  }
>
> -static int prepare_elf_headers(void **addr, unsigned long *sz)
I agree to make arch_crash_populate_cmem more generic, and leave
arch_crash_populate_cmem & prepare_elf64_ram_headers_callback here as
callbacks.

Reviewed-by: Guo Ren <[email protected]>

> +int arch_crash_populate_cmem(struct crash_mem *cmem)
>  {
> -       struct crash_mem *cmem;
> -       unsigned int nr_ranges;
> -       int ret;
> -
> -       nr_ranges = 2; /* For exclusion of crashkernel region */
> -       walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
> -
> -       cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
> -       if (!cmem)
> -               return -ENOMEM;
> -
> -       cmem->max_nr_ranges = nr_ranges;
> -       cmem->nr_ranges = 0;
> -       ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
> -       if (ret)
> -               goto out;
> -
> -       /* Exclude crashkernel region */
> -       ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
> -       if (ret)
> -               goto out;
> -
> -       if (crashk_low_res.end) {
> -               ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
> -               if (ret)
> -                       goto out;
> -       }
> -
> -       ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
> -
> -out:
> -       kfree(cmem);
> -       return ret;
> +       return walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
>  }
>
>  static char *setup_kdump_cmdline(struct kimage *image, char *cmdline,
> @@ -282,7 +259,7 @@ int load_extra_segments(struct kimage *image, unsigned long kernel_start,
>         if (image->type == KEXEC_TYPE_CRASH) {
>                 void *headers;
>                 unsigned long headers_sz;
> -               ret = prepare_elf_headers(&headers, &headers_sz);
> +               ret = crash_prepare_headers(true, &headers, &headers_sz, NULL);
>                 if (ret) {
>                         pr_err("Preparing elf core header failed\n");
>                         goto out;
> --
> 2.34.1
>


-- 
Best Regards
 Guo Ren