Merge tag 'sti-dt-fixes-for-v4.8-rcs' of git://git.kernel.org/pub/scm/linux/kernel...

[cascardo/linux.git] / arch / s390 / boot / compressed / head.S

diff --git a/arch/s390/boot/compressed/head.S b/arch/s390/boot/compressed/head.S
index f86a4ee..28c4f96 100644 (file)
--- a/arch/s390/boot/compressed/head.S
+++ b/arch/s390/boot/compressed/head.S
@@ -21,16 +21,21 @@ ENTRY(startup_continue)
        lg      %r15,.Lstack-.LPG1(%r13)
        aghi    %r15,-160
        brasl   %r14,decompress_kernel
-       # setup registers for memory mover & branch to target
+       # Set up registers for memory mover. We move the decompressed image to
+       # 0x11000, starting at offset 0x11000 in the decompressed image so
+       # that code living at 0x11000 in the image will end up at 0x11000 in
+       # memory.
        lgr     %r4,%r2
        lg      %r2,.Loffset-.LPG1(%r13)
        la      %r4,0(%r2,%r4)
        lg      %r3,.Lmvsize-.LPG1(%r13)
        lgr     %r5,%r3
-       # move the memory mover someplace safe
+       # Move the memory mover someplace safe so it doesn't overwrite itself.
        la      %r1,0x200
        mvc     0(mover_end-mover,%r1),mover-.LPG1(%r13)
-       # decompress image is started at 0x11000
+       # When the memory mover is done we pass control to
+       # arch/s390/kernel/head64.S:startup_continue which lives at 0x11000 in
+       # the decompressed image.
        lgr     %r6,%r2
        br      %r1
 mover: