powerpc: Setup relocation on exceptions for bare metal systems

This turns on MMU on execptions via AIL field in the LPCR.
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/reg.h

@@ -249,6 +249,8 @@
 #define   LPCR_RMLS    0x1C000000      /* impl dependent rmo limit sel */
 #define	  LPCR_RMLS_SH	(63-37)
 #define   LPCR_ILE     0x02000000      /* !HV irqs set MSR:LE */
+#define   LPCR_AIL_0	0x00000000	/* MMU off exception offset 0x0 */
+#define   LPCR_AIL_3	0x01800000	/* MMU on exception offset 0xc00...4xxx */
 #define   LPCR_PECE	0x00007000	/* powersave exit cause enable */
 #define     LPCR_PECE0	0x00004000	/* ext. exceptions can cause exit */
 #define     LPCR_PECE1	0x00002000	/* decrementer can cause exit */

arch/powerpc/kernel/cpu_setup_power.S

@@ -54,6 +54,7 @@ _GLOBAL(__setup_cpu_power8)
 	li	r0,0
 	mtspr	SPRN_LPID,r0
 	mfspr	r3,SPRN_LPCR
+	oris	r3, r3, LPCR_AIL_3@h
 	bl	__init_LPCR
 	bl	__init_TLB
 	mtlr	r11
@@ -67,6 +68,7 @@ _GLOBAL(__restore_cpu_power8)
 	li	r0,0
 	mtspr	SPRN_LPID,r0
 	mfspr   r3,SPRN_LPCR
+	oris	r3, r3, LPCR_AIL_3@h
 	bl	__init_LPCR
 	bl	__init_TLB
 	mtlr	r11