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>

2 files changed, 15 insertions, 5 deletions

diff --git a/arch/powerpc/kernel/cpu_setup_power.S b/arch/powerpc/kernel/cpu_setup_power.S
index 37d1bb002aa9..1557e7c2c7e1 100644
--- a/arch/powerpc/kernel/cpu_setup_power.S
+++ b/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
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 1d33e817ab2d..3d7a50a08f5e 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/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 */