powerpc/powernv: Add OPAL takeover from PowerVM

On machines supporting the OPAL firmware version 1, the system
is initially booted under pHyp. We then use a special hypercall
to verify if OPAL is available and if it is, we then trigger
a "takeover" which disables pHyp and loads the OPAL runtime
firmware, giving control to the kernel in hypervisor mode.

This patch add the necessary code to detect that the OPAL takeover
capability is present when running under PowerVM (aka pHyp) and
perform said takeover to get hypervisor control of the processor.

To perform the takeover, we must first use RTAS (within Open
Firmware runtime environment) to start all processors & threads,
in order to give control to OPAL on all of them. We then call
the takeover hypercall on everybody, OPAL will re-enter the kernel
main entry point passing it a flat device-tree.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 50 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
new file mode 100644
index 00000000000..ecdb283f8b7
--- /dev/null
+++ b/arch/powerpc/include/asm/opal.h
@@ -0,0 +1,50 @@
+/*
+ * PowerNV OPAL definitions.
+ *
+ * Copyright 2011 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef __OPAL_H
+#define __OPAL_H
+
+/****** Takeover interface ********/
+
+/* PAPR H-Call used to querty the HAL existence and/or instanciate
+ * it from within pHyp (tech preview only).
+ *
+ * This is exclusively used in prom_init.c
+ */
+
+#ifndef __ASSEMBLY__
+
+struct opal_takeover_args {
+        u64     k_image;                /* r4 */
+        u64     k_size;                 /* r5 */
+        u64     k_entry;                /* r6 */
+        u64     k_entry2;               /* r7 */
+        u64     hal_addr;               /* r8 */
+        u64     rd_image;               /* r9 */
+        u64     rd_size;                /* r10 */
+        u64     rd_loc;                 /* r11 */
+};
+
+extern long opal_query_takeover(u64 *hal_size, u64 *hal_align);
+
+extern long opal_do_takeover(struct opal_takeover_args *args);
+
+extern int opal_enter_rtas(struct rtas_args *args,
+                           unsigned long data,
+                           unsigned long entry);
+
+
+#endif /* __ASSEMBLY__ */
+
+/****** OPAL APIs ******/
+
+
+#endif /* __OPAL_H */