[powerpc v6 1/3] Setup AMOR in HV mode

[Balbir Singh <bsingharora@gmail.com>]

AMOR should be setup in HV mode, we set it up once
and let the generic kernel handle IAMR. This patch is
used to enable storage keys in a following patch as
defined in ISA 3. We don't setup AMOR in DD1, since we
can't setup IAMR in DD1 (bits have to be 0). If we setup
AMOR some other code could potentially try to set IAMR
(guest kernel for example).

Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
---
 arch/powerpc/mm/pgtable-radix.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index ed7bddc..7aa104d 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -320,6 +320,27 @@ static void update_hid_for_radix(void)
 		cpu_relax();
 }
 
+/*
+ * In HV mode, we init AMOR so that the hypervisor
+ * and guest can setup IMAR, enable key 0 and set
+ * it to 1
+ * AMOR = 1100....00 (Mask for key 0 is 11)
+ */
+static void radix_init_amor(void)
+{
+	unsigned long amor_mask = 0xc000000000000000;
+	unsigned long amor;
+
+	/*
+	 * The amor bits are unused in DD1
+	 */
+	if (cpu_has_feature(CPU_FTR_POWER9_DD1))
+		return;
+
+	amor = amor_mask;
+	mtspr(SPRN_AMOR, amor);
+}
+
 void __init radix__early_init_mmu(void)
 {
 	unsigned long lpcr;
@@ -376,6 +397,7 @@ 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();
 	}
 
 	radix_init_pgtable();
@@ -393,6 +415,7 @@ void radix__early_init_mmu_secondary(void)
 
 		mtspr(SPRN_PTCR,
 		      __pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
+		radix_init_amor();
 	}
 }
 
-- 
2.5.5