powerpc/mm/hash/4k: Free hugetlb page table caches correctly.

With 4k page size for hugetlb we allocate hugepage directories from its on slab
cache. With patch 0c4d2680 ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
we missed to free these allocated hugepd tables.

Update pgtable_free to handle hugetlb hugepd directory table.

Fixes: 0c4d2680 ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Add CONFIG_HUGETLB_PAGE guard to fix build break]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/book3s/32/pgalloc.h

@@ -108,6 +108,7 @@ static inline void pgtable_free(void *table, unsigned index_size)
 }
 
 #define check_pgt_cache()	do { } while (0)
+#define get_hugepd_cache_index(x)  (x)
 
 #ifdef CONFIG_SMP
 static inline void pgtable_free_tlb(struct mmu_gather *tlb,

arch/powerpc/include/asm/book3s/64/pgtable-4k.h

@@ -49,6 +49,27 @@ static inline int hugepd_ok(hugepd_t hpd)
 }
 #define is_hugepd(hpd)		(hugepd_ok(hpd))
 
+/*
+ * 16M and 16G huge page directory tables are allocated from slab cache
+ *
+ */
+#define H_16M_CACHE_INDEX (PAGE_SHIFT + H_PTE_INDEX_SIZE + H_PMD_INDEX_SIZE - 24)
+#define H_16G_CACHE_INDEX                                                      \
+	(PAGE_SHIFT + H_PTE_INDEX_SIZE + H_PMD_INDEX_SIZE + H_PUD_INDEX_SIZE - 34)
+
+static inline int get_hugepd_cache_index(int index)
+{
+	switch (index) {
+	case H_16M_CACHE_INDEX:
+		return HTLB_16M_INDEX;
+	case H_16G_CACHE_INDEX:
+		return HTLB_16G_INDEX;
+	default:
+		BUG();
+	}
+	/* should not reach */
+}
+
 #else /* !CONFIG_HUGETLB_PAGE */
 static inline int pmd_huge(pmd_t pmd) { return 0; }
 static inline int pud_huge(pud_t pud) { return 0; }

arch/powerpc/include/asm/book3s/64/pgtable-64k.h

@@ -45,8 +45,17 @@ static inline int hugepd_ok(hugepd_t hpd)
 {
 	return 0;
 }
+
 #define is_hugepd(pdep)			0
 
+/*
+ * This should never get called
+ */
+static inline int get_hugepd_cache_index(int index)
+{
+	BUG();
+}
+
 #else /* !CONFIG_HUGETLB_PAGE */
 static inline int pmd_huge(pmd_t pmd) { return 0; }
 static inline int pud_huge(pud_t pud) { return 0; }

arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -287,6 +287,11 @@ enum pgtable_index {
 	PMD_INDEX,
 	PUD_INDEX,
 	PGD_INDEX,
+	/*
+	 * Below are used with 4k page size and hugetlb
+	 */
+	HTLB_16M_INDEX,
+	HTLB_16G_INDEX,
 };
 
 extern unsigned long __vmalloc_start;

arch/powerpc/include/asm/nohash/32/pgalloc.h

@@ -109,6 +109,7 @@ static inline void pgtable_free(void *table, unsigned index_size)
 }
 
 #define check_pgt_cache()	do { } while (0)
+#define get_hugepd_cache_index(x)	(x)
 
 #ifdef CONFIG_SMP
 static inline void pgtable_free_tlb(struct mmu_gather *tlb,

arch/powerpc/include/asm/nohash/64/pgalloc.h

@@ -141,6 +141,7 @@ static inline void pgtable_free(void *table, int shift)
 	}
 }
 
+#define get_hugepd_cache_index(x)	(x)
 #ifdef CONFIG_SMP
 static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
 {

arch/powerpc/mm/hugetlbpage.c

@@ -337,7 +337,8 @@ static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshif
 	if (shift >= pdshift)
 		hugepd_free(tlb, hugepte);
 	else
-		pgtable_free_tlb(tlb, hugepte, pdshift - shift);
+		pgtable_free_tlb(tlb, hugepte,
+				 get_hugepd_cache_index(pdshift - shift));
 }
 
 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,

arch/powerpc/mm/pgtable-book3s64.c

@@ -409,6 +409,18 @@ static inline void pgtable_free(void *table, int index)
 	case PUD_INDEX:
 		kmem_cache_free(PGT_CACHE(PUD_CACHE_INDEX), table);
 		break;
+#if defined(CONFIG_PPC_4K_PAGES) && defined(CONFIG_HUGETLB_PAGE)
+		/* 16M hugepd directory at pud level */
+	case HTLB_16M_INDEX:
+		BUILD_BUG_ON(H_16M_CACHE_INDEX <= 0);
+		kmem_cache_free(PGT_CACHE(H_16M_CACHE_INDEX), table);
+		break;
+		/* 16G hugepd directory at the pgd level */
+	case HTLB_16G_INDEX:
+		BUILD_BUG_ON(H_16G_CACHE_INDEX <= 0);
+		kmem_cache_free(PGT_CACHE(H_16G_CACHE_INDEX), table);
+		break;
+#endif
 		/* We don't free pgd table via RCU callback */
 	default:
 		BUG();