powerpc/fsl: Force coherent memory on e500mc derivatives
In CoreNet systems it is not allowed to mix M and non-M mappings to the
same memory, and coherent DMA accesses are considered to be M mappings
for this purpose. Ignoring this has been observed to cause hard
lockups in non-SMP kernels on e6500.
Furthermore, e6500 implements the LRAT (logical to real address table)
which allows KVM guests to control the WIMGE bits. This means that
KVM cannot force the M bit on the way it usually does, so the guest had
better set it itself.
Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/arch/powerpc/include/asm/pte-common.h b/arch/powerpc/include/asm/pte-common.h
index b7c8d07..71537a3 100644
--- a/arch/powerpc/include/asm/pte-common.h
+++ b/arch/powerpc/include/asm/pte-common.h
@@ -109,7 +109,8 @@
* the processor might need it for DMA coherency.
*/
#define _PAGE_BASE_NC (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_PSIZE)
-#if defined(CONFIG_SMP) || defined(CONFIG_PPC_STD_MMU)
+#if defined(CONFIG_SMP) || defined(CONFIG_PPC_STD_MMU) || \
+ defined(CONFIG_PPC_E500MC)
#define _PAGE_BASE (_PAGE_BASE_NC | _PAGE_COHERENT)
#else
#define _PAGE_BASE (_PAGE_BASE_NC)
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index 3e68d1c..f3bd5e7 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -1313,11 +1313,14 @@
sync
isync
-/* The mapping only needs to be cache-coherent on SMP */
-#ifdef CONFIG_SMP
-#define M_IF_SMP MAS2_M
+/*
+ * The mapping only needs to be cache-coherent on SMP, except on
+ * Freescale e500mc derivatives where it's also needed for coherent DMA.
+ */
+#if defined(CONFIG_SMP) || defined(CONFIG_PPC_E500MC)
+#define M_IF_NEEDED MAS2_M
#else
-#define M_IF_SMP 0
+#define M_IF_NEEDED 0
#endif
/* 6. Setup KERNELBASE mapping in TLB[0]
@@ -1332,7 +1335,7 @@
ori r6,r6,(MAS1_TSIZE(BOOK3E_PAGESZ_1GB))@l
mtspr SPRN_MAS1,r6
- LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET | M_IF_SMP)
+ LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET | M_IF_NEEDED)
mtspr SPRN_MAS2,r6
rlwinm r5,r5,0,0,25
diff --git a/arch/powerpc/kernel/fsl_booke_entry_mapping.S b/arch/powerpc/kernel/fsl_booke_entry_mapping.S
index f22e7e4..83dd0f6 100644
--- a/arch/powerpc/kernel/fsl_booke_entry_mapping.S
+++ b/arch/powerpc/kernel/fsl_booke_entry_mapping.S
@@ -152,11 +152,14 @@
tlbivax 0,r9
TLBSYNC
-/* The mapping only needs to be cache-coherent on SMP */
-#ifdef CONFIG_SMP
-#define M_IF_SMP MAS2_M
+/*
+ * The mapping only needs to be cache-coherent on SMP, except on
+ * Freescale e500mc derivatives where it's also needed for coherent DMA.
+ */
+#if defined(CONFIG_SMP) || defined(CONFIG_PPC_E500MC)
+#define M_IF_NEEDED MAS2_M
#else
-#define M_IF_SMP 0
+#define M_IF_NEEDED 0
#endif
#if defined(ENTRY_MAPPING_BOOT_SETUP)
@@ -167,8 +170,8 @@
lis r6,(MAS1_VALID|MAS1_IPROT)@h
ori r6,r6,(MAS1_TSIZE(BOOK3E_PAGESZ_64M))@l
mtspr SPRN_MAS1,r6
- lis r6,MAS2_VAL(PAGE_OFFSET, BOOK3E_PAGESZ_64M, M_IF_SMP)@h
- ori r6,r6,MAS2_VAL(PAGE_OFFSET, BOOK3E_PAGESZ_64M, M_IF_SMP)@l
+ lis r6,MAS2_VAL(PAGE_OFFSET, BOOK3E_PAGESZ_64M, M_IF_NEEDED)@h
+ ori r6,r6,MAS2_VAL(PAGE_OFFSET, BOOK3E_PAGESZ_64M, M_IF_NEEDED)@l
mtspr SPRN_MAS2,r6
mtspr SPRN_MAS3,r8
tlbwe
diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c
index 9c90e66..354ba3c 100644
--- a/arch/powerpc/mm/fsl_booke_mmu.c
+++ b/arch/powerpc/mm/fsl_booke_mmu.c
@@ -112,7 +112,7 @@
tsize = __ilog2(size) - 10;
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) || defined(CONFIG_PPC_E500MC)
if ((flags & _PAGE_NO_CACHE) == 0)
flags |= _PAGE_COHERENT;
#endif