diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
new file mode 100644
index 0000000..ecdb283
--- /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 */
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index e708abe..dea8191 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -51,6 +51,10 @@
  *  For pSeries or server processors:
  *   1. The MMU is off & open firmware is running in real mode.
  *   2. The kernel is entered at __start
+ * -or- For OPAL entry:
+ *   1. The MMU is off, processor in HV mode, primary CPU enters at 0
+ *      with device-tree in gpr3
+ *   2. Secondary processors enter at 0x60 with PIR in gpr3
  *
  *  For iSeries:
  *   1. The MMU is on (as it always is for iSeries)
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index a909f4e..9369287 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -43,6 +43,7 @@
 #include <asm/btext.h>
 #include <asm/sections.h>
 #include <asm/machdep.h>
+#include <asm/opal.h>
 
 #include <linux/linux_logo.h>
 
@@ -185,6 +186,7 @@ static unsigned long __initdata prom_tce_alloc_end;
 #define PLATFORM_LPAR		0x0001
 #define PLATFORM_POWERMAC	0x0400
 #define PLATFORM_GENERIC	0x0500
+#define PLATFORM_OPAL		0x0600
 
 static int __initdata of_platform;
 
@@ -644,7 +646,7 @@ static void __init early_cmdline_parse(void)
 	}
 }
 
-#ifdef CONFIG_PPC_PSERIES
+#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
 /*
  * There are two methods for telling firmware what our capabilities are.
  * Newer machines have an "ibm,client-architecture-support" method on the
@@ -1274,6 +1276,195 @@ static void __init prom_init_mem(void)
 	prom_printf("  ram_top      : %x\n", RELOC(ram_top));
 }
 
+static void __init prom_close_stdin(void)
+{
+	struct prom_t *_prom = &RELOC(prom);
+	ihandle val;
+
+	if (prom_getprop(_prom->chosen, "stdin", &val, sizeof(val)) > 0)
+		call_prom("close", 1, 0, val);
+}
+
+#ifdef CONFIG_PPC_POWERNV
+
+static u64 __initdata prom_opal_size;
+static u64 __initdata prom_opal_align;
+static int __initdata prom_rtas_start_cpu;
+static u64 __initdata prom_rtas_data;
+static u64 __initdata prom_rtas_entry;
+
+/* XXX Don't change this structure without updating opal-takeover.S */
+static struct opal_secondary_data {
+	s64				ack;	/*  0 */
+	u64				go;	/*  8 */
+	struct opal_takeover_args	args;	/* 16 */
+} opal_secondary_data;
+
+extern char opal_secondary_entry;
+
+static void prom_query_opal(void)
+{
+	long rc;
+
+	prom_printf("Querying for OPAL presence... ");
+	rc = opal_query_takeover(&RELOC(prom_opal_size),
+				 &RELOC(prom_opal_align));
+	prom_debug("(rc = %ld) ", rc);
+	if (rc != 0) {
+		prom_printf("not there.\n");
+		return;
+	}
+	RELOC(of_platform) = PLATFORM_OPAL;
+	prom_printf(" there !\n");
+	prom_debug("  opal_size  = 0x%lx\n", RELOC(prom_opal_size));
+	prom_debug("  opal_align = 0x%lx\n", RELOC(prom_opal_align));
+	if (RELOC(prom_opal_align) < 0x10000)
+		RELOC(prom_opal_align) = 0x10000;
+}
+
+static int prom_rtas_call(int token, int nargs, int nret, int *outputs, ...)
+{
+	struct rtas_args rtas_args;
+	va_list list;
+	int i;
+
+	rtas_args.token = token;
+	rtas_args.nargs = nargs;
+	rtas_args.nret  = nret;
+	rtas_args.rets  = (rtas_arg_t *)&(rtas_args.args[nargs]);
+	va_start(list, outputs);
+	for (i = 0; i < nargs; ++i)
+		rtas_args.args[i] = va_arg(list, rtas_arg_t);
+	va_end(list);
+
+	for (i = 0; i < nret; ++i)
+		rtas_args.rets[i] = 0;
+
+	opal_enter_rtas(&rtas_args, RELOC(prom_rtas_data),
+			RELOC(prom_rtas_entry));
+
+	if (nret > 1 && outputs != NULL)
+		for (i = 0; i < nret-1; ++i)
+			outputs[i] = rtas_args.rets[i+1];
+	return (nret > 0)? rtas_args.rets[0]: 0;
+}
+
+static void __init prom_opal_hold_cpus(void)
+{
+	int i, cnt, cpu, rc;
+	long j;
+	phandle node;
+	char type[64];
+	u32 servers[8];
+	struct prom_t *_prom = &RELOC(prom);
+	void *entry = (unsigned long *)&RELOC(opal_secondary_entry);
+	struct opal_secondary_data *data = &RELOC(opal_secondary_data);
+
+	prom_debug("prom_opal_hold_cpus: start...\n");
+	prom_debug("    - entry       = 0x%x\n", entry);
+	prom_debug("    - data        = 0x%x\n", data);
+
+	data->ack = -1;
+	data->go = 0;
+
+	/* look for cpus */
+	for (node = 0; prom_next_node(&node); ) {
+		type[0] = 0;
+		prom_getprop(node, "device_type", type, sizeof(type));
+		if (strcmp(type, RELOC("cpu")) != 0)
+			continue;
+
+		/* Skip non-configured cpus. */
+		if (prom_getprop(node, "status", type, sizeof(type)) > 0)
+			if (strcmp(type, RELOC("okay")) != 0)
+				continue;
+
+		cnt = prom_getprop(node, "ibm,ppc-interrupt-server#s", servers,
+			     sizeof(servers));
+		if (cnt == PROM_ERROR)
+			break;
+		cnt >>= 2;
+		for (i = 0; i < cnt; i++) {
+			cpu = servers[i];
+			prom_debug("CPU %d ... ", cpu);
+			if (cpu == _prom->cpu) {
+				prom_debug("booted !\n");
+				continue;
+			}
+			prom_debug("starting ... ");
+
+			/* Init the acknowledge var which will be reset by
+			 * the secondary cpu when it awakens from its OF
+			 * spinloop.
+			 */
+			data->ack = -1;
+			rc = prom_rtas_call(RELOC(prom_rtas_start_cpu), 3, 1,
+					    NULL, cpu, entry, data);
+			prom_debug("rtas rc=%d ...", rc);
+
+			for (j = 0; j < 100000000 && data->ack == -1; j++) {
+				HMT_low();
+				mb();
+			}
+			HMT_medium();
+			if (data->ack != -1)
+				prom_debug("done, PIR=0x%x\n", data->ack);
+			else
+				prom_debug("timeout !\n");
+		}
+	}
+	prom_debug("prom_opal_hold_cpus: end...\n");
+}
+
+static void prom_opal_takeover(void)
+{
+	struct opal_secondary_data *data = &RELOC(opal_secondary_data);
+	struct opal_takeover_args *args = &data->args;
+	u64 align = RELOC(prom_opal_align);
+	u64 top_addr, opal_addr;
+
+	args->k_image	= (u64)RELOC(_stext);
+	args->k_size	= _end - _stext;
+	args->k_entry	= 0;
+	args->k_entry2	= 0x60;
+
+	top_addr = _ALIGN_UP(args->k_size, align);
+
+	if (RELOC(prom_initrd_start) != 0) {
+		args->rd_image = RELOC(prom_initrd_start);
+		args->rd_size = RELOC(prom_initrd_end) - args->rd_image;
+		args->rd_loc = top_addr;
+		top_addr = _ALIGN_UP(args->rd_loc + args->rd_size, align);
+	}
+
+	/* Pickup an address for the HAL. We want to go really high
+	 * up to avoid problem with future kexecs. On the other hand
+	 * we don't want to be all over the TCEs on P5IOC2 machines
+	 * which are going to be up there too. We assume the machine
+	 * has plenty of memory, and we ask for the HAL for now to
+	 * be just below the 1G point, or above the initrd
+	 */
+	opal_addr = _ALIGN_DOWN(0x40000000 - RELOC(prom_opal_size), align);
+	if (opal_addr < top_addr)
+		opal_addr = top_addr;
+	args->hal_addr = opal_addr;
+
+	prom_debug("  k_image    = 0x%lx\n", args->k_image);
+	prom_debug("  k_size     = 0x%lx\n", args->k_size);
+	prom_debug("  k_entry    = 0x%lx\n", args->k_entry);
+	prom_debug("  k_entry2   = 0x%lx\n", args->k_entry2);
+	prom_debug("  hal_addr   = 0x%lx\n", args->hal_addr);
+	prom_debug("  rd_image   = 0x%lx\n", args->rd_image);
+	prom_debug("  rd_size    = 0x%lx\n", args->rd_size);
+	prom_debug("  rd_loc     = 0x%lx\n", args->rd_loc);
+	prom_printf("Performing OPAL takeover,this can take a few minutes..\n");
+	prom_close_stdin();
+	mb();
+	data->go = 1;
+	for (;;)
+		opal_do_takeover(args);
+}
+#endif /* CONFIG_PPC_POWERNV */
 
 /*
  * Allocate room for and instantiate RTAS
@@ -1326,6 +1517,12 @@ static void __init prom_instantiate_rtas(void)
 	prom_setprop(rtas_node, "/rtas", "linux,rtas-entry",
 		     &entry, sizeof(entry));
 
+#ifdef CONFIG_PPC_POWERNV
+	/* PowerVN takeover hack */
+	RELOC(prom_rtas_data) = base;
+	RELOC(prom_rtas_entry) = entry;
+	prom_getprop(rtas_node, "start-cpu", &RELOC(prom_rtas_start_cpu), 4);
+#endif
 	prom_debug("rtas base     = 0x%x\n", base);
 	prom_debug("rtas entry    = 0x%x\n", entry);
 	prom_debug("rtas size     = 0x%x\n", (long)size);
@@ -1543,7 +1740,7 @@ static void __init prom_hold_cpus(void)
 		*acknowledge = (unsigned long)-1;
 
 		if (reg != _prom->cpu) {
-			/* Primary Thread of non-boot cpu */
+			/* Primary Thread of non-boot cpu or any thread */
 			prom_printf("starting cpu hw idx %lu... ", reg);
 			call_prom("start-cpu", 3, 0, node,
 				  secondary_hold, reg);
@@ -1652,15 +1849,6 @@ static void __init prom_init_stdout(void)
 		prom_setprop(val, path, "linux,boot-display", NULL, 0);
 }
 
-static void __init prom_close_stdin(void)
-{
-	struct prom_t *_prom = &RELOC(prom);
-	ihandle val;
-
-	if (prom_getprop(_prom->chosen, "stdin", &val, sizeof(val)) > 0)
-		call_prom("close", 1, 0, val);
-}
-
 static int __init prom_find_machine_type(void)
 {
 	struct prom_t *_prom = &RELOC(prom);
@@ -2504,6 +2692,7 @@ static void __init prom_check_initrd(unsigned long r3, unsigned long r4)
 #endif /* CONFIG_BLK_DEV_INITRD */
 }
 
+
 /*
  * We enter here early on, when the Open Firmware prom is still
  * handling exceptions and the MMU hash table for us.
@@ -2565,7 +2754,7 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
 	 */
 	prom_check_initrd(r3, r4);
 
-#ifdef CONFIG_PPC_PSERIES
+#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
 	/*
 	 * On pSeries, inform the firmware about our capabilities
 	 */
@@ -2611,14 +2800,30 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
 #endif
 
 	/*
-	 * On non-powermacs, try to instantiate RTAS and puts all CPUs
-	 * in spin-loops. PowerMacs don't have a working RTAS and use
-	 * a different way to spin CPUs
+	 * On non-powermacs, try to instantiate RTAS. PowerMacs don't
+	 * have a usable RTAS implementation.
 	 */
-	if (RELOC(of_platform) != PLATFORM_POWERMAC) {
+	if (RELOC(of_platform) != PLATFORM_POWERMAC)
 		prom_instantiate_rtas();
-		prom_hold_cpus();
+
+#ifdef CONFIG_PPC_POWERNV
+	/* Detect HAL and try instanciating it & doing takeover */
+	if (RELOC(of_platform) == PLATFORM_PSERIES_LPAR) {
+		prom_query_opal();
+		if (RELOC(of_platform) == PLATFORM_OPAL) {
+			prom_opal_hold_cpus();
+			prom_opal_takeover();
+		}
 	}
+#endif
+
+	/*
+	 * On non-powermacs, put all CPUs in spin-loops.
+	 *
+	 * PowerMacs use a different mechanism to spin CPUs
+	 */
+	if (RELOC(of_platform) != PLATFORM_POWERMAC)
+		prom_hold_cpus();
 
 	/*
 	 * Fill in some infos for use by the kernel later on
diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh
index 9f82f49..20af6aa 100644
--- a/arch/powerpc/kernel/prom_init_check.sh
+++ b/arch/powerpc/kernel/prom_init_check.sh
@@ -20,7 +20,8 @@ WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
 _end enter_prom memcpy memset reloc_offset __secondary_hold
 __secondary_hold_acknowledge __secondary_hold_spinloop __start
 strcmp strcpy strlcpy strlen strncmp strstr logo_linux_clut224
-reloc_got2 kernstart_addr memstart_addr linux_banner"
+reloc_got2 kernstart_addr memstart_addr linux_banner _stext
+opal_query_takeover opal_do_takeover opal_enter_rtas opal_secondary_entry"
 
 NM="$1"
 OBJ="$2"
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index 1c43250..4971330 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -1,2 +1,2 @@
-obj-y			+= setup.o
+obj-y			+= setup.o opal-takeover.o
 obj-$(CONFIG_SMP)	+= smp.o
diff --git a/arch/powerpc/platforms/powernv/opal-takeover.S b/arch/powerpc/platforms/powernv/opal-takeover.S
new file mode 100644
index 0000000..77b48b2
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-takeover.S
@@ -0,0 +1,140 @@
+/*
+ * PowerNV OPAL takeover assembly code, for use by prom_init.c
+ *
+ * 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.
+ */
+
+#include <asm/ppc_asm.h>
+#include <asm/hvcall.h>
+#include <asm/asm-offsets.h>
+#include <asm/opal.h>
+
+#define STK_PARAM(i)	(48 + ((i)-3)*8)
+
+#define H_HAL_TAKEOVER			0x5124
+#define H_HAL_TAKEOVER_QUERY_MAGIC	-1
+
+	.text
+_GLOBAL(opal_query_takeover)
+	mfcr	r0
+	stw	r0,8(r1)
+	std	r3,STK_PARAM(r3)(r1)
+	std	r4,STK_PARAM(r4)(r1)
+	li	r3,H_HAL_TAKEOVER
+	li	r4,H_HAL_TAKEOVER_QUERY_MAGIC
+	HVSC
+	ld	r10,STK_PARAM(r3)(r1)
+	std	r4,0(r10)
+	ld	r10,STK_PARAM(r4)(r1)
+	std	r5,0(r10)
+	lwz	r0,8(r1)
+	mtcrf	0xff,r0
+	blr
+
+_GLOBAL(opal_do_takeover)
+	mfcr	r0
+	stw	r0,8(r1)
+	mflr	r0
+	std	r0,16(r1)
+	bl	__opal_do_takeover
+	ld	r0,16(r1)
+	mtlr	r0
+	lwz	r0,8(r1)
+	mtcrf	0xff,r0
+	blr
+
+__opal_do_takeover:
+	ld	r4,0(r3)
+	ld	r5,0x8(r3)
+	ld	r6,0x10(r3)
+	ld	r7,0x18(r3)
+	ld	r8,0x20(r3)
+	ld	r9,0x28(r3)
+	ld	r10,0x30(r3)
+	ld	r11,0x38(r3)
+	li	r3,H_HAL_TAKEOVER
+	HVSC
+	blr
+
+	.globl opal_secondary_entry
+opal_secondary_entry:
+	mr	r31,r3
+	mfmsr	r11
+	li	r12,(MSR_SF | MSR_ISF)@highest
+	sldi	r12,r12,48
+	or	r11,r11,r12
+	mtmsrd	r11
+	isync
+	mfspr	r4,SPRN_PIR
+	std	r4,0(r3)
+1:	HMT_LOW
+	ld	r4,8(r3)
+	cmpli	cr0,r4,0
+	beq	1b
+	HMT_MEDIUM
+1:	addi	r3,r31,16
+	bl	__opal_do_takeover
+	b	1b
+
+_GLOBAL(opal_enter_rtas)
+	mflr	r0
+	std	r0,16(r1)
+        stdu	r1,-PROM_FRAME_SIZE(r1)	/* Save SP and create stack space */
+
+	/* Because PROM is running in 32b mode, it clobbers the high order half
+	 * of all registers that it saves.  We therefore save those registers
+	 * PROM might touch to the stack.  (r0, r3-r13 are caller saved)
+	*/
+	SAVE_GPR(2, r1)
+	SAVE_GPR(13, r1)
+	SAVE_8GPRS(14, r1)
+	SAVE_10GPRS(22, r1)
+	mfcr	r10
+	mfmsr	r11
+	std	r10,_CCR(r1)
+	std	r11,_MSR(r1)
+
+	/* Get the PROM entrypoint */
+	mtlr	r5
+
+	/* Switch MSR to 32 bits mode
+	 */
+        li      r12,1
+        rldicr  r12,r12,MSR_SF_LG,(63-MSR_SF_LG)
+        andc    r11,r11,r12
+        li      r12,1
+        rldicr  r12,r12,MSR_ISF_LG,(63-MSR_ISF_LG)
+        andc    r11,r11,r12
+        mtmsrd  r11
+        isync
+
+	/* Enter RTAS here... */
+	blrl
+
+	/* Just make sure that r1 top 32 bits didn't get
+	 * corrupt by OF
+	 */
+	rldicl	r1,r1,0,32
+
+	/* Restore the MSR (back to 64 bits) */
+	ld	r0,_MSR(r1)
+	MTMSRD(r0)
+        isync
+
+	/* Restore other registers */
+	REST_GPR(2, r1)
+	REST_GPR(13, r1)
+	REST_8GPRS(14, r1)
+	REST_10GPRS(22, r1)
+	ld	r4,_CCR(r1)
+	mtcr	r4
+
+        addi	r1,r1,PROM_FRAME_SIZE
+	ld	r0,16(r1)
+	mtlr    r0
+	blr
