[PATCH v6 14/19] powerpc/mm/hash: Increase VA range to 128TB

[Michael Ellerman]

From: "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com>

We update the hash linux page table layout such that we can support
512TB. But we limit the TASK_SIZE to 128TB. We can switch to 128TB by
default without conditional because that is the max virtual address
supported by other architectures. We will later add a mechanism to
on-demand increase the application's effective address range to 512TB.

Having the page table layout changed to accommodate 512TB makes testing
large memory configuration easier with less code changes to kernel

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
---
 arch/powerpc/include/asm/book3s/64/hash-4k.h  |  2 +-
 arch/powerpc/include/asm/book3s/64/hash-64k.h |  2 +-
 arch/powerpc/include/asm/processor.h          | 22 ++++++++++++++++++----
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
index 0c4e470571ca..b4b5e6b671ca 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
@@ -8,7 +8,7 @@
 #define H_PTE_INDEX_SIZE  9
 #define H_PMD_INDEX_SIZE  7
 #define H_PUD_INDEX_SIZE  9
-#define H_PGD_INDEX_SIZE  9
+#define H_PGD_INDEX_SIZE  12
 
 #ifndef __ASSEMBLY__
 #define H_PTE_TABLE_SIZE	(sizeof(pte_t) << H_PTE_INDEX_SIZE)
diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index 7be54f9590a3..214219dff87c 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -4,7 +4,7 @@
 #define H_PTE_INDEX_SIZE  8
 #define H_PMD_INDEX_SIZE  5
 #define H_PUD_INDEX_SIZE  5
-#define H_PGD_INDEX_SIZE  12
+#define H_PGD_INDEX_SIZE  15
 
 /*
  * 64k aligned address free up few of the lower bits of RPN for us
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index e0fecbcea2a2..ea4b6c696f1f 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -102,11 +102,25 @@ void release_thread(struct task_struct *);
 #endif
 
 #ifdef CONFIG_PPC64
-/* 64-bit user address space is 46-bits (64TB user VM) */
-#define TASK_SIZE_USER64 (0x0000400000000000UL)
+/*
+ * 64-bit user address space can have multiple limits
+ * For now supported values are:
+ */
+#define TASK_SIZE_64TB  (0x0000400000000000UL)
+#define TASK_SIZE_128TB (0x0000800000000000UL)
+#define TASK_SIZE_512TB (0x0002000000000000UL)
 
-/* 
- * 32-bit user address space is 4GB - 1 page 
+#ifdef CONFIG_PPC_BOOK3S_64
+/*
+ * Max value currently used:
+ */
+#define TASK_SIZE_USER64 TASK_SIZE_128TB
+#else
+#define TASK_SIZE_USER64 TASK_SIZE_64TB
+#endif
+
+/*
+ * 32-bit user address space is 4GB - 1 page
  * (this 1 page is needed so referencing of 0xFFFFFFFF generates EFAULT
  */
 #define TASK_SIZE_USER32 (0x0000000100000000UL - (1*PAGE_SIZE))
-- 
2.7.4