[qemu-s390x] [kvm-unit-tests PATCH 1/5] s390x: Make tests bootable from disk

[Janosch Frank]

Currently tests are run with the --kernel option of Qemu, which will
load the ELF file and jump to the start address. When booting from
disk, we need to specify a start address. This is done by setting the
initial short PSW at 0x0.

For later compatibility with other hypervisors the short psw has 31
bit addressing specified.

Signed-off-by: Janosch Frank <address@hidden>
---
 s390x/cstart64.S | 9 +++++++--
 s390x/flat.lds   | 8 +++++++-
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/s390x/cstart64.S b/s390x/cstart64.S
index dc7ddd6..abd6b58 100644
--- a/s390x/cstart64.S
+++ b/s390x/cstart64.S
@@ -14,12 +14,17 @@
 
 .section .init
 
-/* entry point - for KVM + TCG we directly start in 64 bit mode */
+/*
+ * Short init between 0x10000 and 0x10480 and then jump to 0x11000.
+ * 0x10480 - 0x11000 are written to by bootloader.
+ */
        .globl start
 start:
+       sam64                           # Set addressing mode to 64 bit
+start64:
        /* setup stack */
        larl    %r15, stackptr
-       /* setup initial PSW mask + control registers*/
+       /* setup initial PSW mask + control registers */
        larl    %r1, initial_psw
        lpswe   0(%r1)
 init_psw_cont:
diff --git a/s390x/flat.lds b/s390x/flat.lds
index b6e2172..7cfd9f9 100644
--- a/s390x/flat.lds
+++ b/s390x/flat.lds
@@ -1,10 +1,16 @@
 SECTIONS
 {
+       .lowcore : {
+               . = 0;
+                LONG(0x00080000)
+                LONG(0x80010000)
+       }
+       . = 0x10000;
        .text : {
                *(.init)
                . = 0x480;
                ipl_args = .;
-               . = 0x600;
+               .  = 0x1000;
                *(.text)
                *(.text.*)
        }
-- 
2.14.3