On 3/16/23 05:11, Baoquan He wrote:
On 03/06/23 at 11:22am, Eric DeVolder wrote:
......
+static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
+{
+ /* Obtain lock while changing crash information */
+ if (kexec_trylock()) {
+
+ /* Check kdump is loaded */
+ if (kexec_crash_image) {
+ struct kimage *image = kexec_crash_image;
+
+ if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
+ hp_action == KEXEC_CRASH_HP_REMOVE_CPU)
+ pr_debug("hp_action %u, cpu %u\n", hp_action, cpu);
+ else
+ pr_debug("hp_action %u\n", hp_action);
+
+ /*
+ * When the struct kimage is allocated, the elfcorehdr_index
+ * is set to -1. Find the segment containing the elfcorehdr,
+ * if not already found. This works for both the kexec_load
+ * and kexec_file_load paths.
+ */
+ if (image->elfcorehdr_index < 0) {
+ unsigned long mem;
+ unsigned char *ptr;
+ unsigned int n;
+
+ for (n = 0; n < image->nr_segments; n++) {
+ mem = image->segment[n].mem;
+ ptr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
+ if (ptr) {
+ /* The segment containing elfcorehdr */
+ if (memcmp(ptr, ELFMAG, SELFMAG) == 0) {
+ image->elfcorehdr_index = (int)n;
+ }
+ kunmap_local(ptr);
+ }
+ }
+ }
+
+ if (image->elfcorehdr_index < 0) {
+ pr_err("unable to locate elfcorehdr segment");
+ goto out;
+ }
+
+ /* Needed in order for the segments to be updated */
+ arch_kexec_unprotect_crashkres();
+
+ /* Differentiate between normal load and hotplug update */
+ image->hp_action = hp_action;
+
+ /* Now invoke arch-specific update handler */
+ arch_crash_handle_hotplug_event(image);
+
+ /* No longer handling a hotplug event */
+ image->hp_action = KEXEC_CRASH_HP_NONE;
+ image->elfcorehdr_updated = true;
It's good to initialize the image->hp_action here, however where do
you check it? Do you plan to add some check somewhere?
Hi Baoquan,
The hp_action member is initialized to 0 in do_image_alloc_init(). I've
mapped KEXEC_CRASH_HP_NONE onto 0 on purpose.
But the use of image->hp_action = KEXEC_CRASH_HP_NONE is to actually
delineate that a hotplug event handling has completed. You can see
imae->hp_action set to hp_action to capture what the triggering event
was, as passed into this function.
I will go ahead and set image->hp_action = KEXEC_CRASH_HP_NONE; explicitly
in do_kimage_alloc_init(), as that is done for the other crash hotplug members.
Thanks!
eric
+
+ /* Change back to read-only */
+ arch_kexec_protect_crashkres();
+ }
+
+out:
+ /* Release lock now that update complete */
+ kexec_unlock();
+ }
+}
......
_______________________________________________
kexec mailing list
kexec@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/kexec
