powerpc/mm: Make page table size a variable

Radix and hash MMU models support different page table sizes. Make
the #defines a variable so that existing code can work with variable
sizes.

Slice related code is only used by hash, so use hash constants there. We
will replicate some of the boundary conditions with resepct to TASK_SIZE
using radix values too. Right now we do boundary condition check using
hash constants.

Swapper pgdir size is initialized in asm code. We select the max pgd
size to keep it simple. For now we select hash pgdir. When adding radix
we will switch that to radix pgdir which is 64K.

BUILD_BUG_ON check which is removed is already done in hugepage_init()
using MAYBE_BUILD_BUG_ON().

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

7 files changed, 41 insertions, 16 deletions

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 2a193f28b6c7..aafc613656fc 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -870,6 +870,18 @@ static void __init htab_initialize(void)
 
 void __init early_init_mmu(void)
 {
+	/*
+	 * initialize page table size
+	 */
+	__pte_index_size = H_PTE_INDEX_SIZE;
+	__pmd_index_size = H_PMD_INDEX_SIZE;
+	__pud_index_size = H_PUD_INDEX_SIZE;
+	__pgd_index_size = H_PGD_INDEX_SIZE;
+	__pmd_cache_index = H_PMD_CACHE_INDEX;
+	__pte_table_size = H_PTE_TABLE_SIZE;
+	__pmd_table_size = H_PMD_TABLE_SIZE;
+	__pud_table_size = H_PUD_TABLE_SIZE;
+	__pgd_table_size = H_PGD_TABLE_SIZE;
 	/* Initialize the MMU Hash table and create the linear mapping
 	 * of memory. Has to be done before SLB initialization as this is
 	 * currently where the page size encoding is obtained.
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 8d1daf7d9785..09ca65e55b58 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -66,11 +66,11 @@
 #include "mmu_decl.h"
 
 #ifdef CONFIG_PPC_STD_MMU_64
-#if PGTABLE_RANGE > USER_VSID_RANGE
+#if H_PGTABLE_RANGE > USER_VSID_RANGE
 #warning Limited user VSID range means pagetable space is wasted
 #endif
 
-#if (TASK_SIZE_USER64 < PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE)
+#if (TASK_SIZE_USER64 < H_PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE)
 #warning TASK_SIZE is smaller than it needs to be.
 #endif
 #endif /* CONFIG_PPC_STD_MMU_64 */
diff --git a/arch/powerpc/mm/pgtable-book3e.c b/arch/powerpc/mm/pgtable-book3e.c
index b323735a8360..a2298930f990 100644
--- a/arch/powerpc/mm/pgtable-book3e.c
+++ b/arch/powerpc/mm/pgtable-book3e.c
@@ -77,6 +77,7 @@ int map_kernel_page(unsigned long ea, unsigned long pa, unsigned long flags)
 	pmd_t *pmdp;
 	pte_t *ptep;
 
+	BUILD_BUG_ON(TASK_SIZE_USER64 > PGTABLE_RANGE);
 	if (slab_is_available()) {
 		pgdp = pgd_offset_k(ea);
 		pudp = pud_alloc(&init_mm, pgdp, ea);
diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c
index f405a67c807a..6f5fa68c784e 100644
--- a/arch/powerpc/mm/pgtable-hash64.c
+++ b/arch/powerpc/mm/pgtable-hash64.c
@@ -61,6 +61,7 @@ int map_kernel_page(unsigned long ea, unsigned long pa, unsigned long flags)
 	pmd_t *pmdp;
 	pte_t *ptep;
 
+	BUILD_BUG_ON(TASK_SIZE_USER64 > H_PGTABLE_RANGE);
 	if (slab_is_available()) {
 		pgdp = pgd_offset_k(ea);
 		pudp = pud_alloc(&init_mm, pgdp, ea);
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 1fe356cad7f6..dafcd9ff78df 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -58,11 +58,6 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/thp.h>
 
-/* Some sanity checking */
-#if TASK_SIZE_USER64 > PGTABLE_RANGE
-#error TASK_SIZE_USER64 exceeds pagetable range
-#endif
-
 #ifdef CONFIG_PPC_STD_MMU_64
 #if TASK_SIZE_USER64 > (1UL << (ESID_BITS + SID_SHIFT))
 #error TASK_SIZE_USER64 exceeds user VSID range
@@ -75,6 +70,28 @@
  */
 struct prtb_entry *process_tb;
 struct patb_entry *partition_tb;
+/*
+ * page table size
+ */
+unsigned long __pte_index_size;
+EXPORT_SYMBOL(__pte_index_size);
+unsigned long __pmd_index_size;
+EXPORT_SYMBOL(__pmd_index_size);
+unsigned long __pud_index_size;
+EXPORT_SYMBOL(__pud_index_size);
+unsigned long __pgd_index_size;
+EXPORT_SYMBOL(__pgd_index_size);
+unsigned long __pmd_cache_index;
+EXPORT_SYMBOL(__pmd_cache_index);
+unsigned long __pte_table_size;
+EXPORT_SYMBOL(__pte_table_size);
+unsigned long __pmd_table_size;
+EXPORT_SYMBOL(__pmd_table_size);
+unsigned long __pud_table_size;
+EXPORT_SYMBOL(__pud_table_size);
+unsigned long __pgd_table_size;
+EXPORT_SYMBOL(__pgd_table_size);
+
 #endif
 unsigned long ioremap_bot = IOREMAP_BASE;
 
@@ -739,12 +756,6 @@ pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 int has_transparent_hugepage(void)
 {
 
-	BUILD_BUG_ON_MSG((PMD_SHIFT - PAGE_SHIFT) >= MAX_ORDER,
-		"hugepages can't be allocated by the buddy allocator");
-
-	BUILD_BUG_ON_MSG((PMD_SHIFT - PAGE_SHIFT) < 2,
-			 "We need more than 2 pages to do deferred thp split");
-
 	if (!mmu_has_feature(MMU_FTR_16M_PAGE))
 		return 0;
 	/*
diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
index d3374004d20d..15b8f712b50b 100644
--- a/arch/powerpc/mm/slb_low.S
+++ b/arch/powerpc/mm/slb_low.S
@@ -35,7 +35,7 @@ _GLOBAL(slb_allocate_realmode)
 	 * check for bad kernel/user address
 	 * (ea & ~REGION_MASK) >= PGTABLE_RANGE
 	 */
-	rldicr. r9,r3,4,(63 - PGTABLE_EADDR_SIZE - 4)
+	rldicr. r9,r3,4,(63 - H_PGTABLE_EADDR_SIZE - 4)
 	bne-	8f
 
 	srdi	r9,r3,60		/* get region */
diff --git a/arch/powerpc/mm/slice.c b/arch/powerpc/mm/slice.c
index 42954f0b47ac..ee21b8699cee 100644
--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -37,8 +37,8 @@
 #include <asm/hugetlb.h>
 
 /* some sanity checks */
-#if (PGTABLE_RANGE >> 43) > SLICE_MASK_SIZE
-#error PGTABLE_RANGE exceeds slice_mask high_slices size
+#if (H_PGTABLE_RANGE >> 43) > SLICE_MASK_SIZE
+#error H_PGTABLE_RANGE exceeds slice_mask high_slices size
 #endif
 
 static DEFINE_SPINLOCK(slice_convert_lock);