powerpc/mm/hash64: Map all the kernel regions in the same 0xc range

This patch maps vmalloc, IO and vmemap regions in the 0xc address range
instead of the current 0xd and 0xf range. This brings the mapping closer
to radix translation mode.

With hash 64K page size each of this region is 512TB whereas with 4K config
we are limited by the max page table range of 64TB and hence there regions
are of 16TB size.

The kernel mapping is now:

 On 4K hash

     kernel_region_map_size = 16TB
     kernel vmalloc start   = 0xc000100000000000
     kernel IO start        = 0xc000200000000000
     kernel vmemmap start   = 0xc000300000000000

64K hash, 64K radix and 4k radix:

     kernel_region_map_size = 512TB
     kernel vmalloc start   = 0xc008000000000000
     kernel IO start        = 0xc00a000000000000
     kernel vmemmap start   = 0xc00c000000000000

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

1 files changed, 15 insertions, 16 deletions

diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index eeb40091b46b..8a30bf189f10 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -588,7 +588,8 @@ extern void slb_set_size(u16 size);
 #endif
 
 #define MAX_VMALLOC_CTX_CNT	1
-#define MAX_MEMMAP_CTX_CNT	1
+#define MAX_IO_CTX_CNT		1
+#define MAX_VMEMMAP_CTX_CNT	1
 
 /*
  * 256MB segment
@@ -601,13 +602,10 @@ extern void slb_set_size(u16 size);
  * would give a protovsid of 0x1fffffffff. That will result in a VSID 0
  * because of the modulo operation in vsid scramble.
  *
- * We add one extra context to MIN_USER_CONTEXT so that we can map kernel
- * context easily. The +1 is to map the unused 0xe region mapping.
  */
 #define MAX_USER_CONTEXT	((ASM_CONST(1) << CONTEXT_BITS) - 2)
 #define MIN_USER_CONTEXT	(MAX_KERNEL_CTX_CNT + MAX_VMALLOC_CTX_CNT + \
-				 MAX_MEMMAP_CTX_CNT + 2)
-
+				 MAX_IO_CTX_CNT + MAX_VMEMMAP_CTX_CNT)
 /*
  * For platforms that support on 65bit VA we limit the context bits
  */
@@ -776,7 +774,7 @@ static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
 	/*
 	 * Bad address. We return VSID 0 for that
 	 */
-	if ((ea & ~REGION_MASK) >= H_PGTABLE_RANGE)
+	if ((ea & EA_MASK)  >= H_PGTABLE_RANGE)
 		return 0;
 
 	if (!mmu_has_feature(MMU_FTR_68_BIT_VA))
@@ -803,28 +801,29 @@ static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
  * 0x00002 -  [ 0xc002000000000000 - 0xc003ffffffffffff]
  * 0x00003 -  [ 0xc004000000000000 - 0xc005ffffffffffff]
  * 0x00004 -  [ 0xc006000000000000 - 0xc007ffffffffffff]
-
- * 0x00005 -  [ 0xd000000000000000 - 0xd001ffffffffffff ]
- * 0x00006 -  Not used - Can map 0xe000000000000000 range.
- * 0x00007 -  [ 0xf000000000000000 - 0xf001ffffffffffff ]
  *
- * So we can compute the context from the region (top nibble) by
- * subtracting 11, or 0xc - 1.
+ * vmap, IO, vmemap
+ *
+ * 0x00005 -  [ 0xc008000000000000 - 0xc009ffffffffffff]
+ * 0x00006 -  [ 0xc00a000000000000 - 0xc00bffffffffffff]
+ * 0x00007 -  [ 0xc00c000000000000 - 0xc00dffffffffffff]
+ *
  */
 static inline unsigned long get_kernel_context(unsigned long ea)
 {
-	unsigned long region_id = REGION_ID(ea);
+	unsigned long region_id = get_region_id(ea);
 	unsigned long ctx;
 	/*
-	 * For linear mapping we do support multiple context
+	 * Depending on Kernel config, kernel region can have one context
+	 * or more.
 	 */
 	if (region_id == KERNEL_REGION_ID) {
 		/*
 		 * We already verified ea to be not beyond the addr limit.
 		 */
-		ctx =  1 + ((ea & ~REGION_MASK) >> MAX_EA_BITS_PER_CONTEXT);
+		ctx =  1 + ((ea & EA_MASK) >> MAX_EA_BITS_PER_CONTEXT);
 	} else
-		ctx = (region_id - 0xc) + MAX_KERNEL_CTX_CNT;
+		ctx = region_id + MAX_KERNEL_CTX_CNT - 2;
 	return ctx;
 }