powerpc/ppc64: Do not turn AIL (reloc-on interrupts) too early

Turn them on at the same time as we allow MSR_IR/DR in the paca
kernel MSR, ie, after the MMU has been setup enough to be able
to handle relocated access to the linear mapping.

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

arch/powerpc/kernel/cpu_setup_power.S

@@ -56,7 +56,6 @@ _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_HFSCR
 	bl	__init_tlb_power8
@@ -75,7 +74,6 @@ _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_HFSCR
 	bl	__init_tlb_power8

arch/powerpc/kernel/setup_64.c

@@ -195,6 +195,18 @@ static void fixup_boot_paca(void)
 	get_paca()->data_offset = 0;
 }
 
+static void cpu_ready_for_interrupts(void)
+{
+	/* Set IR and DR in PACA MSR */
+	get_paca()->kernel_msr = MSR_KERNEL;
+
+	/* Enable AIL if supported */
+	if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
+		unsigned long lpcr = mfspr(SPRN_LPCR);
+		mtspr(SPRN_LPCR, lpcr | LPCR_AIL_3);
+	}
+}
+
 /*
  * Early initialization entry point. This is called by head.S
  * with MMU translation disabled. We rely on the "feature" of
@@ -264,9 +276,9 @@ void __init early_setup(unsigned long dt_ptr)
 	/*
 	 * At this point, we can let interrupts switch to virtual mode
 	 * (the MMU has been setup), so adjust the MSR in the PACA to
-	 * have IR and DR set.
+	 * have IR and DR set and enable AIL if it exists
 	 */
-	get_paca()->kernel_msr = MSR_KERNEL;
+	cpu_ready_for_interrupts();
 
 	/* Reserve large chunks of memory for use by CMA for KVM */
 	kvm_cma_reserve();
@@ -307,7 +319,7 @@ void early_setup_secondary(void)
 	 * (the MMU has been setup), so adjust the MSR in the PACA to
 	 * have IR and DR set.
 	 */
-	get_paca()->kernel_msr = MSR_KERNEL;
+	cpu_ready_for_interrupts();
 }
 
 #endif /* CONFIG_SMP */