On 04/01/22 at 02:30pm, Eric DeVolder wrote:
> For kexec_file_load support, the loading of the crash kernel occurs
> entirely within the kernel, and as such the elfcorehdr is readily
> identified (so that it can be modified upon hotplug events).
>
> This change enables support for kexec_load by identifying the
> elfcorehdr segment in the arch_crash_hotplug_handler(), if it has
> not already been identified.
>
> Signed-off-by: Eric DeVolder <eric.devolder@xxxxxxxxxx>
LGTM,
Acked-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
> arch/x86/kernel/crash.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
> index 101c030ac038..682f130b83e3 100644
> --- a/arch/x86/kernel/crash.c
> +++ b/arch/x86/kernel/crash.c
> @@ -486,6 +486,30 @@ void arch_crash_hotplug_handler(struct kimage *image,
> void *elfbuf = NULL;
> unsigned long mem, memsz;
>
> + /*
> + * When the struct kimage is alloced, it is wiped to zero, so
> + * the elfcorehdr_index_valid defaults to false. It is set on the
> + * kexec_file_load path, or here for kexec_load, if not already
> + * identified.
> + */
> + if (!image->elfcorehdr_index_valid) {
> + unsigned int n;
> +
> + for (n = 0; n < image->nr_segments; n++) {
> + mem = image->segment[n].mem;
> + memsz = image->segment[n].memsz;
> + ptr = map_crash_pages(mem, memsz);
> + if (ptr) {
> + /* The segment containing elfcorehdr */
> + if (memcmp(ptr, ELFMAG, SELFMAG) == 0) {
> + image->elfcorehdr_index = (int)n;
> + image->elfcorehdr_index_valid = true;
> + }
> + }
> + unmap_crash_pages((void **)&ptr);
> + }
> + }
> +
> if (!image->elfcorehdr_index_valid) {
> pr_err("crash hp: unable to locate elfcorehdr segment");
> goto out;
> --
> 2.27.0
>
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