[PATCH v8 07/20] powerpc/mm: add helpers to get/set mm.context->pte_frag

From: Christophe Leroy
Date: Thu Nov 29 2018 - 03:10:21 EST


In order to handle pte_fragment functions with single fragment
without adding pte_frag in all mm_context_t, this patch creates
two helpers which do nothing on platforms using a single fragment.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/include/asm/pgtable.h | 31 +++++++++++++++++++++++++++++++
arch/powerpc/mm/pgtable-frag.c | 8 ++++----
2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 9679b7519a35..734df2210749 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -110,6 +110,37 @@ void mark_initmem_nx(void);
static inline void mark_initmem_nx(void) { }
#endif

+/*
+ * When used, PTE_FRAG_NR is defined in subarch pgtable.h
+ * so we are sure it is included when arriving here.
+ */
+#ifndef PTE_FRAG_NR
+#define PTE_FRAG_NR 1
+#define PTE_FRAG_SIZE_SHIFT PAGE_SHIFT
+#define PTE_FRAG_SIZE (1UL << PTE_FRAG_SIZE_SHIFT)
+#endif
+
+#if PTE_FRAG_NR != 1
+static inline void *pte_frag_get(mm_context_t *ctx)
+{
+ return ctx->pte_frag;
+}
+
+static inline void pte_frag_set(mm_context_t *ctx, void *p)
+{
+ ctx->pte_frag = p;
+}
+#else
+static inline void *pte_frag_get(mm_context_t *ctx)
+{
+ return NULL;
+}
+
+static inline void pte_frag_set(mm_context_t *ctx, void *p)
+{
+}
+#endif
+
#endif /* __ASSEMBLY__ */

#endif /* _ASM_POWERPC_PGTABLE_H */
diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
index 7544d0d7177d..af23a587f019 100644
--- a/arch/powerpc/mm/pgtable-frag.c
+++ b/arch/powerpc/mm/pgtable-frag.c
@@ -38,7 +38,7 @@ static pte_t *get_pte_from_cache(struct mm_struct *mm)
return NULL;

spin_lock(&mm->page_table_lock);
- ret = mm->context.pte_frag;
+ ret = pte_frag_get(&mm->context);
if (ret) {
pte_frag = ret + PTE_FRAG_SIZE;
/*
@@ -46,7 +46,7 @@ static pte_t *get_pte_from_cache(struct mm_struct *mm)
*/
if (((unsigned long)pte_frag & ~PAGE_MASK) == 0)
pte_frag = NULL;
- mm->context.pte_frag = pte_frag;
+ pte_frag_set(&mm->context, pte_frag);
}
spin_unlock(&mm->page_table_lock);
return (pte_t *)ret;
@@ -86,9 +86,9 @@ static pte_t *__alloc_for_ptecache(struct mm_struct *mm, int kernel)
* the allocated page with single fragement
* count.
*/
- if (likely(!mm->context.pte_frag)) {
+ if (likely(!pte_frag_get(&mm->context))) {
atomic_set(&page->pt_frag_refcount, PTE_FRAG_NR);
- mm->context.pte_frag = ret + PTE_FRAG_SIZE;
+ pte_frag_set(&mm->context, ret + PTE_FRAG_SIZE);
}
spin_unlock(&mm->page_table_lock);

--
2.13.3