powerpc: Define CPU feature for Architected 2.06 HV mode

This bit indicates that we are operating in hypervisor mode on a CPU
compliant to architecture 2.06 or later (currently server only).

We set it on POWER7 and have a boot-time CPU setup function that
clears it if MSR:HV isn't set (booting under a hypervisor).

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

arch/powerpc/kernel/cpu_setup_power7.S

@@ -0,0 +1,65 @@
+/*
+ * This file contains low level CPU setup functions.
+ *    Copyright (C) 2003 Benjamin Herrenschmidt (benh@kernel.crashing.org)
+ *
+ * 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/processor.h>
+#include <asm/page.h>
+#include <asm/cputable.h>
+#include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/cache.h>
+
+/* Entry: r3 = crap, r4 = ptr to cputable entry
+ *
+ * Note that we can be called twice for pseudo-PVRs
+ */
+_GLOBAL(__setup_cpu_power7)
+	mflr	r11
+	bl	__init_hvmode_206
+	mtlr	r11
+	beqlr
+	bl	__init_LPCR
+	mtlr	r11
+	blr
+
+_GLOBAL(__restore_cpu_power7)
+	mflr	r11
+	mfmsr	r3
+	rldicl.	r0,r3,4,63
+	beqlr
+	bl	__init_LPCR
+	mtlr	r11
+	blr
+
+__init_hvmode_206:
+	/* Disable CPU_FTR_HVMODE_206 and exit if MSR:HV is not set */
+	mfmsr	r3
+	rldicl.	r0,r3,4,63
+	bnelr
+	ld	r5,CPU_SPEC_FEATURES(r4)
+	LOAD_REG_IMMEDIATE(r6,CPU_FTR_HVMODE_206)
+	xor	r5,r5,r6
+	std	r5,CPU_SPEC_FEATURES(r4)
+	blr
+
+__init_LPCR:
+	/* Setup a sane LPCR:
+	 *
+	 *   LPES = 0b11 (SRR0/1 used for 0x500)
+	 *   PECE = 0b111
+	 *
+	 * Other bits untouched for now
+	 */
+	mfspr	r3,SPRN_LPCR
+	ori	r3,r3,(LPCR_LPES0|LPCR_LPES1)
+	ori	r3,r3,(LPCR_PECE0|LPCR_PECE1|LPCR_PECE2)
+	mtspr	SPRN_LPCR,r3
+	isync
+	blr