signal/ia64: Document a conflict with SI_USER with SIGFPE

[mirror_ubuntu-bionic-kernel.git] / kernel / kexec_core.c

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 154ffb489b93de01631ed4810b5042ba6fa8f123..1ae7c41c33c19c54e4b08d33c0c59da78244efba 100644 (file)
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -482,6 +482,40 @@ struct page *kimage_alloc_control_pages(struct kimage *image,
        return pages;
 }
 
+int kimage_crash_copy_vmcoreinfo(struct kimage *image)
+{
+       struct page *vmcoreinfo_page;
+       void *safecopy;
+
+       if (image->type != KEXEC_TYPE_CRASH)
+               return 0;
+
+       /*
+        * For kdump, allocate one vmcoreinfo safe copy from the
+        * crash memory. as we have arch_kexec_protect_crashkres()
+        * after kexec syscall, we naturally protect it from write
+        * (even read) access under kernel direct mapping. But on
+        * the other hand, we still need to operate it when crash
+        * happens to generate vmcoreinfo note, hereby we rely on
+        * vmap for this purpose.
+        */
+       vmcoreinfo_page = kimage_alloc_control_pages(image, 0);
+       if (!vmcoreinfo_page) {
+               pr_warn("Could not allocate vmcoreinfo buffer\n");
+               return -ENOMEM;
+       }
+       safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL);
+       if (!safecopy) {
+               pr_warn("Could not vmap vmcoreinfo buffer\n");
+               return -ENOMEM;
+       }
+
+       image->vmcoreinfo_data_copy = safecopy;
+       crash_update_vmcoreinfo_safecopy(safecopy);
+
+       return 0;
+}
+
 static int kimage_add_entry(struct kimage *image, kimage_entry_t entry)
 {
        if (*image->entry != 0)
@@ -569,6 +603,11 @@ void kimage_free(struct kimage *image)
        if (!image)
                return;
 
+       if (image->vmcoreinfo_data_copy) {
+               crash_update_vmcoreinfo_safecopy(NULL);
+               vunmap(image->vmcoreinfo_data_copy);
+       }
+
        kimage_free_extra_pages(image);
        for_each_kimage_entry(image, ptr, entry) {
                if (entry & IND_INDIRECTION) {