1 files changed, 65 insertions, 0 deletions
diff --git a/src/pc-bios/s390-ccw/start.S b/src/pc-bios/s390-ccw/start.S
new file mode 100644
index 0000000..b6dd8c2
--- /dev/null
+++ b/src/pc-bios/s390-ccw/start.S
@@ -0,0 +1,65 @@
+/*
+ * First stage boot loader for virtio devices. The compiled output goes
+ * into the pc-bios directory of qemu.
+ *
+ * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
+ * Copyright 2013 IBM Corp.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at
+ * your option) any later version. See the COPYING file in the top-level
+ * directory.
+ */
+
+        .globl _start
+_start:
+
+larl	%r15, stack + 0x8000    /* Set up stack */
+larl    %r6, boot_value
+stg     %r7, 0(%r6)     /* save the boot_value before any function calls */
+j	main                    /* And call C */
+
+/*
+ * void disabled_wait(void)
+ *
+ * stops the current guest cpu.
+ */
+	.globl disabled_wait
+disabled_wait:
+        larl %r1,disabled_wait_psw
+        lpswe   0(%r1)
+
+
+/*
+ * void consume_sclp_int(void)
+ *
+ * eats one sclp interrupt
+ */
+        .globl consume_sclp_int
+consume_sclp_int:
+        /* enable service interrupts in cr0 */
+        stctg 0,0,0(15)
+        oi 6(15), 0x2
+        lctlg 0,0,0(15)
+        /* prepare external call handler */
+        larl %r1, external_new_code
+        stg %r1, 0x1b8
+        larl %r1, external_new_mask
+        mvc 0x1b0(8),0(%r1)
+        /* load enabled wait PSW */
+        larl %r1, enabled_wait_psw
+        lpswe 0(%r1)
+
+external_new_code:
+        /* disable service interrupts in cr0 */
+        stctg 0,0,0(15)
+        ni 6(15), 0xfd
+        lctlg 0,0,0(15)
+        br 14
+
+        .align  8
+disabled_wait_psw:
+        .quad   0x0002000180000000,0x0000000000000000
+enabled_wait_psw:
+        .quad   0x0302000180000000,0x0000000000000000
+external_new_mask:
+        .quad   0x0000000180000000