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Commit 0eea0867 authored by Minfei Huang's avatar Minfei Huang Committed by Linus Torvalds
Browse files

kexec: do a cleanup for function kexec_load 



There are a lof of work to be done in function kexec_load, not only for
allocating structs and loading initram, but also for some misc.

To make it more clear, wrap a new function do_kexec_load which is used
to allocate structs and load initram.  And the pre-work will be done in
kexec_load.

Signed-off-by: default avatarMinfei Huang <mnfhuang@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 917a3560

kernel/kexec.c

+69 −56
Original line number Diff line number Diff line
@@ -103,6 +103,74 @@ 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_ON_CRASH)

		crash_map_reserved_pages();



	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();



	/*

	 * Once the reserved memory is mapped, we should unmap this memory

	 * before returning

	 */

	if (flags & KEXEC_ON_CRASH)

		crash_unmap_reserved_pages();

	kimage_free(image);

	return ret;

}



/*

 * Exec Kernel system call: for obvious reasons only root may call it.

 *
@@ -127,7 +195,6 @@ 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 +219,6 @@ 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
@@ -166,63 +230,12 @@ 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 (kexec_crash_image)

			arch_kexec_unprotect_crashkres();

	}



	if (nr_segments > 0) {

		unsigned long i;



		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.

			 */

	result = do_kexec_load(entry, nr_segments, segments, flags);



			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 unmap_page;



		if (flags & KEXEC_PRESERVE_CONTEXT)

			image->preserve_context = 1;

		result = machine_kexec_prepare(image);

		if (result)

			goto unmap_page;



		for (i = 0; i < nr_segments; i++) {

			result = kimage_load_segment(image, &image->segment[i]);

			if (result)

				goto unmap_page;

		}

		kimage_terminate(image);

unmap_page:

		if (flags & KEXEC_ON_CRASH)

			crash_unmap_reserved_pages();

		if (result)

			goto out;

	}

	/* 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();



	mutex_unlock(&kexec_mutex);

	kimage_free(image);



	return result;

}