diff --git a/Documentation/kdump/gdbmacros.txt b/Documentation/kdump/gdbmacros.txt
index 9b9b454b048a..35f6a982a0d5 100644
--- a/Documentation/kdump/gdbmacros.txt
+++ b/Documentation/kdump/gdbmacros.txt
@@ -15,15 +15,16 @@
 
 define bttnobp
 	set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
-	set $pid_off=((size_t)&((struct task_struct *)0)->pids[1].pid_list.next)
+	set $pid_off=((size_t)&((struct task_struct *)0)->thread_group.next)
 	set $init_t=&init_task
 	set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
+	set var $stacksize = sizeof(union thread_union)
 	while ($next_t != $init_t)
 		set $next_t=(struct task_struct *)$next_t
 		printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
 		printf "===================\n"
-		set var $stackp = $next_t.thread.esp
-		set var $stack_top = ($stackp & ~4095) + 4096
+		set var $stackp = $next_t.thread.sp
+		set var $stack_top = ($stackp & ~($stacksize - 1)) + $stacksize
 
 		while ($stackp < $stack_top)
 			if (*($stackp) > _stext && *($stackp) < _sinittext)
@@ -31,13 +32,13 @@ define bttnobp
 			end
 			set $stackp += 4
 		end
-		set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
+		set $next_th=(((char *)$next_t->thread_group.next) - $pid_off)
 		while ($next_th != $next_t)
 			set $next_th=(struct task_struct *)$next_th
 			printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
 			printf "===================\n"
-			set var $stackp = $next_t.thread.esp
-			set var $stack_top = ($stackp & ~4095) + 4096
+			set var $stackp = $next_t.thread.sp
+			set var $stack_top = ($stackp & ~($stacksize - 1)) + stacksize
 
 			while ($stackp < $stack_top)
 				if (*($stackp) > _stext && *($stackp) < _sinittext)
@@ -45,7 +46,7 @@ define bttnobp
 				end
 				set $stackp += 4
 			end
-			set $next_th=(((char *)$next_th->pids[1].pid_list.next) - $pid_off)
+			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
 		end
 		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
 	end
@@ -54,42 +55,44 @@ document bttnobp
 	dump all thread stack traces on a kernel compiled with !CONFIG_FRAME_POINTER
 end
 
+define btthreadstack
+	set var $pid_task = $arg0
+
+	printf "\npid %d; comm %s:\n", $pid_task.pid, $pid_task.comm
+	printf "task struct: "
+	print $pid_task
+	printf "===================\n"
+	set var $stackp = $pid_task.thread.sp
+	set var $stacksize = sizeof(union thread_union)
+	set var $stack_top = ($stackp & ~($stacksize - 1)) + $stacksize
+	set var $stack_bot = ($stackp & ~($stacksize - 1))
+
+	set $stackp = *((unsigned long *) $stackp)
+	while (($stackp < $stack_top) && ($stackp > $stack_bot))
+		set var $addr = *(((unsigned long *) $stackp) + 1)
+		info symbol $addr
+		set $stackp = *((unsigned long *) $stackp)
+	end
+end
+document btthreadstack
+	 dump a thread stack using the given task structure pointer
+end
+
+
 define btt
 	set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
-	set $pid_off=((size_t)&((struct task_struct *)0)->pids[1].pid_list.next)
+	set $pid_off=((size_t)&((struct task_struct *)0)->thread_group.next)
 	set $init_t=&init_task
 	set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
 	while ($next_t != $init_t)
 		set $next_t=(struct task_struct *)$next_t
-		printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
-		printf "===================\n"
-		set var $stackp = $next_t.thread.esp
-		set var $stack_top = ($stackp & ~4095) + 4096
-		set var $stack_bot = ($stackp & ~4095)
+		btthreadstack $next_t
 
-		set $stackp = *($stackp)
-		while (($stackp < $stack_top) && ($stackp > $stack_bot))
-			set var $addr = *($stackp + 4)
-			info symbol $addr
-			set $stackp = *($stackp)
-		end
-
-		set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
+		set $next_th=(((char *)$next_t->thread_group.next) - $pid_off)
 		while ($next_th != $next_t)
 			set $next_th=(struct task_struct *)$next_th
-			printf "\npid %d; comm %s:\n", $next_t.pid, $next_t.comm
-			printf "===================\n"
-			set var $stackp = $next_t.thread.esp
-			set var $stack_top = ($stackp & ~4095) + 4096
-			set var $stack_bot = ($stackp & ~4095)
-
-			set $stackp = *($stackp)
-			while (($stackp < $stack_top) && ($stackp > $stack_bot))
-				set var $addr = *($stackp + 4)
-				info symbol $addr
-				set $stackp = *($stackp)
-			end
-			set $next_th=(((char *)$next_th->pids[1].pid_list.next) - $pid_off)
+			btthreadstack $next_th
+			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
 		end
 		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
 	end
@@ -101,7 +104,7 @@ end
 define btpid
 	set var $pid = $arg0
 	set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
-	set $pid_off=((size_t)&((struct task_struct *)0)->pids[1].pid_list.next)
+	set $pid_off=((size_t)&((struct task_struct *)0)->thread_group.next)
 	set $init_t=&init_task
 	set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
 	set var $pid_task = 0
@@ -113,29 +116,18 @@ define btpid
 			set $pid_task = $next_t
 		end
 
-		set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
+		set $next_th=(((char *)$next_t->thread_group.next) - $pid_off)
 		while ($next_th != $next_t)
 			set $next_th=(struct task_struct *)$next_th
 			if ($next_th.pid == $pid)
 				set $pid_task = $next_th
 			end
-			set $next_th=(((char *)$next_th->pids[1].pid_list.next) - $pid_off)
+			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
 		end
 		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
 	end
 
-	printf "\npid %d; comm %s:\n", $pid_task.pid, $pid_task.comm
-	printf "===================\n"
-	set var $stackp = $pid_task.thread.esp
-	set var $stack_top = ($stackp & ~4095) + 4096
-	set var $stack_bot = ($stackp & ~4095)
-
-	set $stackp = *($stackp)
-	while (($stackp < $stack_top) && ($stackp > $stack_bot))
-		set var $addr = *($stackp + 4)
-		info symbol $addr
-		set $stackp = *($stackp)
-	end
+	btthreadstack $pid_task
 end
 document btpid
 	backtrace of pid
@@ -145,7 +137,7 @@ end
 define trapinfo
 	set var $pid = $arg0
 	set $tasks_off=((size_t)&((struct task_struct *)0)->tasks)
-	set $pid_off=((size_t)&((struct task_struct *)0)->pids[1].pid_list.next)
+	set $pid_off=((size_t)&((struct task_struct *)0)->thread_group.next)
 	set $init_t=&init_task
 	set $next_t=(((char *)($init_t->tasks).next) - $tasks_off)
 	set var $pid_task = 0
@@ -157,13 +149,13 @@ define trapinfo
 			set $pid_task = $next_t
 		end
 
-		set $next_th=(((char *)$next_t->pids[1].pid_list.next) - $pid_off)
+		set $next_th=(((char *)$next_t->thread_group.next) - $pid_off)
 		while ($next_th != $next_t)
 			set $next_th=(struct task_struct *)$next_th
 			if ($next_th.pid == $pid)
 				set $pid_task = $next_th
 			end
-			set $next_th=(((char *)$next_th->pids[1].pid_list.next) - $pid_off)
+			set $next_th=(((char *)$next_th->thread_group.next) - $pid_off)
 		end
 		set $next_t=(char *)($next_t->tasks.next) - $tasks_off
 	end
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
index fb0901ec4306..f5bf24df5c6d 100644
--- a/arch/s390/kernel/machine_kexec.c
+++ b/arch/s390/kernel/machine_kexec.c
@@ -83,13 +83,13 @@ static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action,
 	switch (action) {
 	case PM_SUSPEND_PREPARE:
 	case PM_HIBERNATION_PREPARE:
-		if (crashk_res.start)
-			crash_map_reserved_pages();
+		if (kexec_crash_image)
+			arch_kexec_unprotect_crashkres();
 		break;
 	case PM_POST_SUSPEND:
 	case PM_POST_HIBERNATION:
-		if (crashk_res.start)
-			crash_unmap_reserved_pages();
+		if (kexec_crash_image)
+			arch_kexec_protect_crashkres();
 		break;
 	default:
 		return NOTIFY_DONE;
@@ -100,6 +100,8 @@ static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action,
 static int __init machine_kdump_pm_init(void)
 {
 	pm_notifier(machine_kdump_pm_cb, 0);
+	/* Create initial mapping for crashkernel memory */
+	arch_kexec_unprotect_crashkres();
 	return 0;
 }
 arch_initcall(machine_kdump_pm_init);
@@ -134,6 +136,8 @@ static int kdump_csum_valid(struct kimage *image)
 #endif
 }
 
+#ifdef CONFIG_CRASH_DUMP
+
 /*
  * Map or unmap crashkernel memory
  */
@@ -155,21 +159,25 @@ static void crash_map_pages(int enable)
 }
 
 /*
- * Map crashkernel memory
+ * Unmap crashkernel memory
  */
-void crash_map_reserved_pages(void)
+void arch_kexec_protect_crashkres(void)
 {
-	crash_map_pages(1);
+	if (crashk_res.end)
+		crash_map_pages(0);
 }
 
 /*
- * Unmap crashkernel memory
+ * Map crashkernel memory
  */
-void crash_unmap_reserved_pages(void)
+void arch_kexec_unprotect_crashkres(void)
 {
-	crash_map_pages(0);
+	if (crashk_res.end)
+		crash_map_pages(1);
 }
 
+#endif
+
 /*
  * Give back memory to hypervisor before new kdump is loaded
  */
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 819ab3f9c9c7..64979821bc2e 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -536,3 +536,48 @@ int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
 	return -ENOEXEC;
 }
 #endif /* CONFIG_KEXEC_FILE */
+
+static int
+kexec_mark_range(unsigned long start, unsigned long end, bool protect)
+{
+	struct page *page;
+	unsigned int nr_pages;
+
+	/*
+	 * For physical range: [start, end]. We must skip the unassigned
+	 * crashk resource with zero-valued "end" member.
+	 */
+	if (!end || start > end)
+		return 0;
+
+	page = pfn_to_page(start >> PAGE_SHIFT);
+	nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
+	if (protect)
+		return set_pages_ro(page, nr_pages);
+	else
+		return set_pages_rw(page, nr_pages);
+}
+
+static void kexec_mark_crashkres(bool protect)
+{
+	unsigned long control;
+
+	kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);
+
+	/* Don't touch the control code page used in crash_kexec().*/
+	control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));
+	/* Control code page is located in the 2nd page. */
+	kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect);
+	control += KEXEC_CONTROL_PAGE_SIZE;
+	kexec_mark_range(control, crashk_res.end, protect);
+}
+
+void arch_kexec_protect_crashkres(void)
+{
+	kexec_mark_crashkres(true);
+}
+
+void arch_kexec_unprotect_crashkres(void)
+{
+	kexec_mark_crashkres(false);
+}
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index d140b1e9faa7..278ee4812300 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -241,8 +241,6 @@ extern void crash_kexec(struct pt_regs *);
 int kexec_should_crash(struct task_struct *);
 void crash_save_cpu(struct pt_regs *regs, int cpu);
 void crash_save_vmcoreinfo(void);
-void crash_map_reserved_pages(void);
-void crash_unmap_reserved_pages(void);
 void arch_crash_save_vmcoreinfo(void);
 __printf(1, 2)
 void vmcoreinfo_append_str(const char *fmt, ...);
@@ -328,6 +326,8 @@ int __weak arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr,
 					Elf_Shdr *sechdrs, unsigned int relsec);
 int __weak arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
 					unsigned int relsec);
+void arch_kexec_protect_crashkres(void);
+void arch_kexec_unprotect_crashkres(void);
 
 #else /* !CONFIG_KEXEC_CORE */
 struct pt_regs;
diff --git a/kernel/kexec.c b/kernel/kexec.c
index d873b64fbddc..e1acab9c8260 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -103,6 +103,65 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
 	return ret;
 }
 
+static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
+		struct kexec_segment __user *segments, unsigned long flags)
+{
+	struct kimage **dest_image, *image;
+	unsigned long i;
+	int ret;
+
+	if (flags & KEXEC_ON_CRASH) {
+		dest_image = &kexec_crash_image;
+		if (kexec_crash_image)
+			arch_kexec_unprotect_crashkres();
+	} else {
+		dest_image = &kexec_image;
+	}
+
+	if (nr_segments == 0) {
+		/* Uninstall image */
+		kimage_free(xchg(dest_image, NULL));
+		return 0;
+	}
+	if (flags & KEXEC_ON_CRASH) {
+		/*
+		 * Loading another kernel to switch to if this one
+		 * crashes.  Free any current crash dump kernel before
+		 * we corrupt it.
+		 */
+		kimage_free(xchg(&kexec_crash_image, NULL));
+	}
+
+	ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags);
+	if (ret)
+		return ret;
+
+	if (flags & KEXEC_PRESERVE_CONTEXT)
+		image->preserve_context = 1;
+
+	ret = machine_kexec_prepare(image);
+	if (ret)
+		goto out;
+
+	for (i = 0; i < nr_segments; i++) {
+		ret = kimage_load_segment(image, &image->segment[i]);
+		if (ret)
+			goto out;
+	}
+
+	kimage_terminate(image);
+
+	/* Install the new kernel and uninstall the old */
+	image = xchg(dest_image, image);
+
+out:
+	if ((flags & KEXEC_ON_CRASH) && kexec_crash_image)
+		arch_kexec_protect_crashkres();
+
+	kimage_free(image);
+	return ret;
+}
+
 /*
  * Exec Kernel system call: for obvious reasons only root may call it.
  *
@@ -127,7 +186,6 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
 SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 		struct kexec_segment __user *, segments, unsigned long, flags)
 {
-	struct kimage **dest_image, *image;
 	int result;
 
 	/* We only trust the superuser with rebooting the system. */
@@ -152,9 +210,6 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 	if (nr_segments > KEXEC_SEGMENT_MAX)
 		return -EINVAL;
 
-	image = NULL;
-	result = 0;
-
 	/* Because we write directly to the reserved memory
 	 * region when loading crash kernels we need a mutex here to
 	 * prevent multiple crash  kernels from attempting to load
@@ -166,53 +221,9 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 	if (!mutex_trylock(&kexec_mutex))
 		return -EBUSY;
 
-	dest_image = &kexec_image;
-	if (flags & KEXEC_ON_CRASH)
-		dest_image = &kexec_crash_image;
-	if (nr_segments > 0) {
-		unsigned long i;
+	result = do_kexec_load(entry, nr_segments, segments, flags);
 
-		if (flags & KEXEC_ON_CRASH) {
-			/*
-			 * Loading another kernel to switch to if this one
-			 * crashes.  Free any current crash dump kernel before
-			 * we corrupt it.
-			 */
-
-			kimage_free(xchg(&kexec_crash_image, NULL));
-			result = kimage_alloc_init(&image, entry, nr_segments,
-						   segments, flags);
-			crash_map_reserved_pages();
-		} else {
-			/* Loading another kernel to reboot into. */
-
-			result = kimage_alloc_init(&image, entry, nr_segments,
-						   segments, flags);
-		}
-		if (result)
-			goto out;
-
-		if (flags & KEXEC_PRESERVE_CONTEXT)
-			image->preserve_context = 1;
-		result = machine_kexec_prepare(image);
-		if (result)
-			goto out;
-
-		for (i = 0; i < nr_segments; i++) {
-			result = kimage_load_segment(image, &image->segment[i]);
-			if (result)
-				goto out;
-		}
-		kimage_terminate(image);
-		if (flags & KEXEC_ON_CRASH)
-			crash_unmap_reserved_pages();
-	}
-	/* Install the new kernel, and  Uninstall the old */
-	image = xchg(dest_image, image);
-
-out:
 	mutex_unlock(&kexec_mutex);
-	kimage_free(image);
 
 	return result;
 }
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 11b64a63c0f8..aa88c32b54f0 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -926,7 +926,6 @@ int crash_shrink_memory(unsigned long new_size)
 	start = roundup(start, KEXEC_CRASH_MEM_ALIGN);
 	end = roundup(start + new_size, KEXEC_CRASH_MEM_ALIGN);
 
-	crash_map_reserved_pages();
 	crash_free_reserved_phys_range(end, crashk_res.end);
 
 	if ((start == end) && (crashk_res.parent != NULL))
@@ -940,7 +939,6 @@ int crash_shrink_memory(unsigned long new_size)
 	crashk_res.end = end - 1;
 
 	insert_resource(&iomem_resource, ram_res);
-	crash_unmap_reserved_pages();
 
 unlock:
 	mutex_unlock(&kexec_mutex);
@@ -1522,13 +1520,14 @@ int kernel_kexec(void)
 }
 
 /*
- * Add and remove page tables for crashkernel memory
+ * Protection mechanism for crashkernel reserved memory after
+ * the kdump kernel is loaded.
  *
  * Provide an empty default implementation here -- architecture
  * code may override this
  */
-void __weak crash_map_reserved_pages(void)
+void __weak arch_kexec_protect_crashkres(void)
 {}
 
-void __weak crash_unmap_reserved_pages(void)
+void __weak arch_kexec_unprotect_crashkres(void)
 {}
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 6030efd4a188..ef2cf637f840 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -327,8 +327,11 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
 		return -EBUSY;
 
 	dest_image = &kexec_image;
-	if (flags & KEXEC_FILE_ON_CRASH)
+	if (flags & KEXEC_FILE_ON_CRASH) {
 		dest_image = &kexec_crash_image;
+		if (kexec_crash_image)
+			arch_kexec_unprotect_crashkres();
+	}
 
 	if (flags & KEXEC_FILE_UNLOAD)
 		goto exchange;
@@ -377,6 +380,9 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
 exchange:
 	image = xchg(dest_image, image);
 out:
+	if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
+		arch_kexec_protect_crashkres();
+
 	mutex_unlock(&kexec_mutex);
 	kimage_free(image);
 	return ret;