powerpc/mm: Extend pte_fragment functionality to PPC32

In order to allow the 8xx to handle pte_fragments, this patch
extends the use of pte_fragments to PPC32 platforms.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/book3s/32/mmu-hash.h

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_POWERPC_BOOK3S_32_MMU_HASH_H_
 #define _ASM_POWERPC_BOOK3S_32_MMU_HASH_H_
+
 /*
  * 32-bit hash table MMU support
  */
@@ -9,6 +10,8 @@
  * BATs
  */
 
+#include <asm/page.h>
+
 /* Block size masks */
 #define BL_128K	0x000
 #define BL_256K 0x001
@@ -43,7 +46,7 @@ struct ppc_bat {
 	u32 batl;
 };
 
-typedef struct page *pgtable_t;
+typedef pte_t *pgtable_t;
 #endif /* !__ASSEMBLY__ */
 
 /*

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

@@ -59,30 +59,31 @@ static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp,
 static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmdp,
 				pgtable_t pte_page)
 {
-	*pmdp = __pmd((page_to_pfn(pte_page) << PAGE_SHIFT) | _PMD_PRESENT);
+	*pmdp = __pmd(__pa(pte_page) | _PMD_PRESENT);
 }
 
-#define pmd_pgtable(pmd) pmd_page(pmd)
+#define pmd_pgtable(pmd) ((pgtable_t)pmd_page_vaddr(pmd))
 
 extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr);
 extern pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addr);
+void pte_frag_destroy(void *pte_frag);
+pte_t *pte_fragment_alloc(struct mm_struct *mm, unsigned long vmaddr, int kernel);
+void pte_fragment_free(unsigned long *table, int kernel);
 
 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 {
-	free_page((unsigned long)pte);
+	pte_fragment_free((unsigned long *)pte, 1);
 }
 
 static inline void pte_free(struct mm_struct *mm, pgtable_t ptepage)
 {
-	pgtable_page_dtor(ptepage);
-	__free_page(ptepage);
+	pte_fragment_free((unsigned long *)ptepage, 0);
 }
 
 static inline void pgtable_free(void *table, unsigned index_size)
 {
 	if (!index_size) {
-		pgtable_page_dtor(virt_to_page(table));
-		free_page((unsigned long)table);
+		pte_fragment_free((unsigned long *)table, 0);
 	} else {
 		BUG_ON(index_size > MAX_PGTABLE_INDEX_SIZE);
 		kmem_cache_free(PGT_CACHE(index_size), table);
@@ -120,6 +121,6 @@ static inline void pgtable_free_tlb(struct mmu_gather *tlb,
 static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
 				  unsigned long address)
 {
-	pgtable_free_tlb(tlb, page_address(table), 0);
+	pgtable_free_tlb(tlb, table, 0);
 }
 #endif /* _ASM_POWERPC_BOOK3S_32_PGALLOC_H */

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

@@ -329,7 +329,7 @@ static inline void __ptep_set_access_flags(struct vm_area_struct *vma,
 #define pte_same(A,B)	(((pte_val(A) ^ pte_val(B)) & ~_PAGE_HASHPTE) == 0)
 
 #define pmd_page_vaddr(pmd)	\
-	((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
+	((unsigned long)__va(pmd_val(pmd) & ~(PTE_TABLE_SIZE - 1)))
 #define pmd_page(pmd)		\
 	pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT)
 
@@ -346,7 +346,8 @@ static inline void __ptep_set_access_flags(struct vm_area_struct *vma,
 #define pte_offset_kernel(dir, addr)	\
 	((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(addr))
 #define pte_offset_map(dir, addr)		\
-	((pte_t *) kmap_atomic(pmd_page(*(dir))) + pte_index(addr))
+	((pte_t *)(kmap_atomic(pmd_page(*(dir))) + \
+		   (pmd_page_vaddr(*(dir)) & ~PAGE_MASK)) + pte_index(addr))
 #define pte_unmap(pte)		kunmap_atomic(pte)
 
 /*

arch/powerpc/include/asm/mmu_context.h

@@ -223,7 +223,7 @@ static inline int arch_dup_mmap(struct mm_struct *oldmm,
 	return 0;
 }
 
-#ifndef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_BOOK3E_64
 static inline void arch_exit_mmap(struct mm_struct *mm)
 {
 }

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

@@ -2,6 +2,8 @@
 #ifndef _ASM_POWERPC_NOHASH_32_MMU_H_
 #define _ASM_POWERPC_NOHASH_32_MMU_H_
 
+#include <asm/page.h>
+
 #if defined(CONFIG_40x)
 /* 40x-style software loaded TLB */
 #include <asm/nohash/32/mmu-40x.h>
@@ -17,7 +19,7 @@
 #endif
 
 #ifndef __ASSEMBLY__
-typedef struct page *pgtable_t;
+typedef pte_t *pgtable_t;
 #endif
 
 #endif /* _ASM_POWERPC_NOHASH_32_MMU_H_ */

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

@@ -61,11 +61,10 @@ static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp,
 static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmdp,
 				pgtable_t pte_page)
 {
-	*pmdp = __pmd((page_to_pfn(pte_page) << PAGE_SHIFT) | _PMD_USER |
-		      _PMD_PRESENT);
+	*pmdp = __pmd(__pa(pte_page) | _PMD_USER | _PMD_PRESENT);
 }
 
-#define pmd_pgtable(pmd) pmd_page(pmd)
+#define pmd_pgtable(pmd) ((pgtable_t)pmd_page_vaddr(pmd))
 #else
 
 static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp,
@@ -77,31 +76,32 @@ static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp,
 static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmdp,
 				pgtable_t pte_page)
 {
-	*pmdp = __pmd((unsigned long)lowmem_page_address(pte_page) | _PMD_PRESENT);
+	*pmdp = __pmd((unsigned long)pte_page | _PMD_PRESENT);
 }
 
-#define pmd_pgtable(pmd) pmd_page(pmd)
+#define pmd_pgtable(pmd) ((pgtable_t)pmd_page_vaddr(pmd))
 #endif
 
 extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr);
 extern pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addr);
+void pte_frag_destroy(void *pte_frag);
+pte_t *pte_fragment_alloc(struct mm_struct *mm, unsigned long vmaddr, int kernel);
+void pte_fragment_free(unsigned long *table, int kernel);
 
 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 {
-	free_page((unsigned long)pte);
+	pte_fragment_free((unsigned long *)pte, 1);
 }
 
 static inline void pte_free(struct mm_struct *mm, pgtable_t ptepage)
 {
-	pgtable_page_dtor(ptepage);
-	__free_page(ptepage);
+	pte_fragment_free((unsigned long *)ptepage, 0);
 }
 
 static inline void pgtable_free(void *table, unsigned index_size)
 {
 	if (!index_size) {
-		pgtable_page_dtor(virt_to_page(table));
-		free_page((unsigned long)table);
+		pte_fragment_free((unsigned long *)table, 0);
 	} else {
 		BUG_ON(index_size > MAX_PGTABLE_INDEX_SIZE);
 		kmem_cache_free(PGT_CACHE(index_size), table);
@@ -140,6 +140,6 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
 				  unsigned long address)
 {
 	tlb_flush_pgtable(tlb, address);
-	pgtable_free_tlb(tlb, page_address(table), 0);
+	pgtable_free_tlb(tlb, table, 0);
 }
 #endif /* _ASM_POWERPC_PGALLOC_32_H */

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

@@ -333,12 +333,12 @@ static inline int pte_young(pte_t pte)
  */
 #ifndef CONFIG_BOOKE
 #define pmd_page_vaddr(pmd)	\
-	((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
+	((unsigned long)__va(pmd_val(pmd) & ~(PTE_TABLE_SIZE - 1)))
 #define pmd_page(pmd)		\
 	pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT)
 #else
 #define pmd_page_vaddr(pmd)	\
-	((unsigned long) (pmd_val(pmd) & PAGE_MASK))
+	((unsigned long)(pmd_val(pmd) & ~(PTE_TABLE_SIZE - 1)))
 #define pmd_page(pmd)		\
 	pfn_to_page((__pa(pmd_val(pmd)) >> PAGE_SHIFT))
 #endif
@@ -357,7 +357,8 @@ static inline int pte_young(pte_t pte)
 	(pmd_bad(*(dir)) ? NULL : (pte_t *)pmd_page_vaddr(*(dir)) + \
 				  pte_index(addr))
 #define pte_offset_map(dir, addr)		\
-	((pte_t *) kmap_atomic(pmd_page(*(dir))) + pte_index(addr))
+	((pte_t *)(kmap_atomic(pmd_page(*(dir))) + \
+		   (pmd_page_vaddr(*(dir)) & ~PAGE_MASK)) + pte_index(addr))
 #define pte_unmap(pte)		kunmap_atomic(pte)
 
 /*

arch/powerpc/include/asm/pgtable.h

@@ -125,6 +125,10 @@ static inline void pte_frag_set(mm_context_t *ctx, void *p)
 	ctx->pte_frag = p;
 }
 #else
+#define PTE_FRAG_NR		1
+#define PTE_FRAG_SIZE_SHIFT	PAGE_SHIFT
+#define PTE_FRAG_SIZE		(1UL << PTE_FRAG_SIZE_SHIFT)
+
 static inline void *pte_frag_get(mm_context_t *ctx)
 {
 	return NULL;

arch/powerpc/mm/Makefile

@@ -18,6 +18,7 @@ obj-$(CONFIG_PPC_BOOK3E_64)   += pgtable-book3e.o
 obj-$(CONFIG_PPC_BOOK3S_64)	+= pgtable-hash64.o hash_utils_64.o slb.o \
 				   $(hash64-y) mmu_context_book3s64.o \
 				   pgtable-book3s64.o pgtable-frag.o
+obj-$(CONFIG_PPC32)		+= pgtable-frag.o
 obj-$(CONFIG_PPC_RADIX_MMU)	+= pgtable-radix.o tlb-radix.o
 obj-$(CONFIG_PPC_BOOK3S_32)	+= ppc_mmu_32.o hash_low_32.o mmu_context_hash32.o
 obj-$(CONFIG_PPC_BOOK3S)	+= tlb_hash$(BITS).o

arch/powerpc/mm/mmu_context.c

@@ -15,6 +15,7 @@
 #include <linux/sched/mm.h>
 
 #include <asm/mmu_context.h>
+#include <asm/pgalloc.h>
 
 #if defined(CONFIG_PPC32)
 static inline void switch_mm_pgdir(struct task_struct *tsk,
@@ -97,3 +98,12 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
 	switch_mmu_context(prev, next, tsk);
 }
 
+#ifdef CONFIG_PPC32
+void arch_exit_mmap(struct mm_struct *mm)
+{
+	void *frag = pte_frag_get(&mm->context);
+
+	if (frag)
+		pte_frag_destroy(frag);
+}
+#endif

arch/powerpc/mm/mmu_context_nohash.c

@@ -385,6 +385,7 @@ int init_new_context(struct task_struct *t, struct mm_struct *mm)
 #endif
 	mm->context.id = MMU_NO_CONTEXT;
 	mm->context.active = 0;
+	pte_frag_set(&mm->context, NULL);
 	return 0;
 }
 
@@ -487,4 +488,3 @@ void __init mmu_context_init(void)
 	next_context = FIRST_CONTEXT;
 	nr_free_contexts = LAST_CONTEXT - FIRST_CONTEXT + 1;
 }
-

arch/powerpc/mm/pgtable_32.c

@@ -45,32 +45,15 @@ extern char etext[], _stext[], _sinittext[], _einittext[];
 
 __ref pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 {
-	pte_t *pte;
+	if (!slab_is_available())
+		return memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);
 
-	if (slab_is_available()) {
-		pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
-	} else {
-		pte = __va(memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE));
-		if (pte)
-			clear_page(pte);
-	}
-	return pte;
+	return (pte_t *)pte_fragment_alloc(mm, address, 1);
 }
 
 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 {
-	struct page *ptepage;
-
-	gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_ACCOUNT;
-
-	ptepage = alloc_pages(flags, 0);
-	if (!ptepage)
-		return NULL;
-	if (!pgtable_page_ctor(ptepage)) {
-		__free_page(ptepage);
-		return NULL;
-	}
-	return ptepage;
+	return (pgtable_t)pte_fragment_alloc(mm, address, 0);
 }
 
 void __iomem *