ppc/85xx: Ensure that MAS8 is zero when writing TLB entries.

Its reset value is random, and we sometimes read uninitialized TLB
arrays.  Make sure that we don't retain MAS8 from reading such an entry
if the VF bit in MAS8 is set, attempts to use the mapping will trap.

Signed-off-by: Scott Wood <scottwood@freescale.com>

diff --git a/cpu/mpc85xx/start.S b/cpu/mpc85xx/start.S
index eaed0e0..7a23b4f 100644 (file)
--- a/cpu/mpc85xx/start.S
+++ b/cpu/mpc85xx/start.S
@@ -156,6 +156,10 @@ _start_e500:
        mtspr   MCSR,r0                 /* machine check syndrome register */
        mtxer   r0                      /* clear integer exception register */
 
+#ifdef CONFIG_SYS_BOOK3E_HV
+       mtspr   MAS8,r0                 /* make sure MAS8 is clear */
+#endif
+
        /* Enable Time Base and Select Time Base Clock */
        lis     r0,HID0_EMCP@h          /* Enable machine check */
 #if defined(CONFIG_ENABLE_36BIT_PHYS)

diff --git a/cpu/mpc85xx/tlb.c b/cpu/mpc85xx/tlb.c
index 0497a29..03c2449 100644 (file)
--- a/cpu/mpc85xx/tlb.c
+++ b/cpu/mpc85xx/tlb.c
@@ -51,6 +51,9 @@ void set_tlb(u8 tlb, u32 epn, u64 rpn,
 #ifdef CONFIG_ENABLE_36BIT_PHYS
        mtspr(MAS7, _mas7);
 #endif
+#ifdef CONFIG_SYS_BOOK3E_HV
+       mtspr(MAS8, 0);
+#endif
        asm volatile("isync;msync;tlbwe;isync");
 
 #ifdef CONFIG_ADDR_MAP

diff --git a/include/asm-ppc/processor.h b/include/asm-ppc/processor.h
index 0a4c66c..3764a5a 100644 (file)
--- a/include/asm-ppc/processor.h
+++ b/include/asm-ppc/processor.h
@@ -518,6 +518,7 @@
 #define SPRN_MAS5      0x275   /* MMU Assist Register 5 */
 #define SPRN_MAS6      0x276   /* MMU Assist Register 6 */
 #define SPRN_MAS7      0x3B0   /* MMU Assist Register 7 */
+#define SPRN_MAS8      0x155   /* MMU Assist Register 8 */
 
 #define SPRN_IVOR32    0x210   /* Interrupt Vector Offset Register 32 */
 #define SPRN_IVOR33    0x211   /* Interrupt Vector Offset Register 33 */
@@ -720,6 +721,7 @@
 #define MAS5   SPRN_MAS5
 #define MAS6   SPRN_MAS6
 #define MAS7   SPRN_MAS7
+#define MAS8   SPRN_MAS8
 
 #if defined(CONFIG_4xx) || defined(CONFIG_44x) || defined(CONFIG_MPC85xx)
 #define DAR_DEAR DEAR