powerpc/mm/radix: Setup AMOR in HV mode to allow key 0

Setup AMOR (Authority Mask Override Register) in HV mode so that the
host and guest kernel can in turn setup IAMR.

This allows us to enable key 0 in a following patch.

Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 8d00ab4222a701b75d458672d25f7f609ae7d282..29e502953688ca89d2278ba8909a75430ed16739 100644 (file)
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -312,6 +312,18 @@ static void update_hid_for_radix(void)
                cpu_relax();
 }
 
+static void radix_init_amor(void)
+{
+       /*
+       * In HV mode, we init AMOR (Authority Mask Override Register) so that
+       * the hypervisor and guest can setup IAMR (Instruction Authority Mask
+       * Register), enable key 0 and set it to 1.
+       *
+       * AMOR = 0b1100 .... 0000 (Mask for key 0 is 11)
+       */
+       mtspr(SPRN_AMOR, (3ul << 62));
+}
+
 void __init radix__early_init_mmu(void)
 {
        unsigned long lpcr;
@@ -368,6 +380,7 @@ void __init radix__early_init_mmu(void)
                lpcr = mfspr(SPRN_LPCR);
                mtspr(SPRN_LPCR, lpcr | LPCR_UPRT | LPCR_HR);
                radix_init_partition_table();
+               radix_init_amor();
        }
 
        memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
@@ -387,6 +400,7 @@ void radix__early_init_mmu_secondary(void)
 
                mtspr(SPRN_PTCR,
                      __pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
+               radix_init_amor();
        }
 }