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Subject[PATCH v6 02/20] powerpc/mm: Move pte_fragment_alloc() to a common location
Date
In preparation of next patch which generalises the use of
pte_fragment_alloc() for all, this patch moves the related functions
in a place that is common to all subarches.

The 8xx will need that for supporting 16k pages, as in that mode
page tables still have a size of 4k.

Since pte_fragment with only once fragment is not different
from what is done in the general case, we can easily migrate all
subarchs to pte fragments.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/include/asm/book3s/64/pgalloc.h | 1 +
arch/powerpc/mm/Makefile | 4 +-
arch/powerpc/mm/mmu_context_book3s64.c | 15 ----
arch/powerpc/mm/pgtable-book3s64.c | 85 --------------------
arch/powerpc/mm/pgtable-frag.c | 116 +++++++++++++++++++++++++++
5 files changed, 120 insertions(+), 101 deletions(-)
create mode 100644 arch/powerpc/mm/pgtable-frag.c

diff --git a/arch/powerpc/include/asm/book3s/64/pgalloc.h b/arch/powerpc/include/asm/book3s/64/pgalloc.h
index bfed4cf3b2f3..6c2808c0f052 100644
--- a/arch/powerpc/include/asm/book3s/64/pgalloc.h
+++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h
@@ -39,6 +39,7 @@ extern struct vmemmap_backing *vmemmap_list;
extern struct kmem_cache *pgtable_cache[];
#define PGT_CACHE(shift) pgtable_cache[shift]

+void pte_frag_destroy(void *pte_frag);
extern pte_t *pte_fragment_alloc(struct mm_struct *, unsigned long, int);
extern pmd_t *pmd_fragment_alloc(struct mm_struct *, unsigned long);
extern void pte_fragment_free(unsigned long *, int);
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index ca96e7be4d0e..3cbb1acf0745 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -15,7 +15,9 @@ obj-$(CONFIG_PPC_MMU_NOHASH) += mmu_context_nohash.o tlb_nohash.o \
obj-$(CONFIG_PPC_BOOK3E) += tlb_low_$(BITS)e.o
hash64-$(CONFIG_PPC_NATIVE) := hash_native_64.o
obj-$(CONFIG_PPC_BOOK3E_64) += pgtable-book3e.o
-obj-$(CONFIG_PPC_BOOK3S_64) += pgtable-hash64.o hash_utils_64.o slb.o $(hash64-y) mmu_context_book3s64.o pgtable-book3s64.o
+obj-$(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_PPC_RADIX_MMU) += pgtable-radix.o tlb-radix.o
obj-$(CONFIG_PPC_STD_MMU_32) += ppc_mmu_32.o hash_low_32.o mmu_context_hash32.o
obj-$(CONFIG_PPC_STD_MMU) += tlb_hash$(BITS).o
diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
index 510f103d7813..f720c5cc0b5e 100644
--- a/arch/powerpc/mm/mmu_context_book3s64.c
+++ b/arch/powerpc/mm/mmu_context_book3s64.c
@@ -164,21 +164,6 @@ static void destroy_contexts(mm_context_t *ctx)
}
}

-static void pte_frag_destroy(void *pte_frag)
-{
- int count;
- struct page *page;
-
- page = virt_to_page(pte_frag);
- /* drop all the pending references */
- count = ((unsigned long)pte_frag & ~PAGE_MASK) >> PTE_FRAG_SIZE_SHIFT;
- /* We allow PTE_FRAG_NR fragments from a PTE page */
- if (atomic_sub_and_test(PTE_FRAG_NR - count, &page->pt_frag_refcount)) {
- pgtable_page_dtor(page);
- __free_page(page);
- }
-}
-
static void pmd_frag_destroy(void *pmd_frag)
{
int count;
diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index 43e99e1d947b..84ff3403239c 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -321,91 +321,6 @@ void pmd_fragment_free(unsigned long *pmd)
}
}

-static pte_t *get_pte_from_cache(struct mm_struct *mm)
-{
- void *pte_frag, *ret;
-
- spin_lock(&mm->page_table_lock);
- ret = mm->context.pte_frag;
- if (ret) {
- pte_frag = ret + PTE_FRAG_SIZE;
- /*
- * If we have taken up all the fragments mark PTE page NULL
- */
- if (((unsigned long)pte_frag & ~PAGE_MASK) == 0)
- pte_frag = NULL;
- mm->context.pte_frag = pte_frag;
- }
- spin_unlock(&mm->page_table_lock);
- return (pte_t *)ret;
-}
-
-static pte_t *__alloc_for_ptecache(struct mm_struct *mm, int kernel)
-{
- void *ret = NULL;
- struct page *page;
-
- if (!kernel) {
- page = alloc_page(PGALLOC_GFP | __GFP_ACCOUNT);
- if (!page)
- return NULL;
- if (!pgtable_page_ctor(page)) {
- __free_page(page);
- return NULL;
- }
- } else {
- page = alloc_page(PGALLOC_GFP);
- if (!page)
- return NULL;
- }
-
- atomic_set(&page->pt_frag_refcount, 1);
-
- ret = page_address(page);
- /*
- * if we support only one fragment just return the
- * allocated page.
- */
- if (PTE_FRAG_NR == 1)
- return ret;
- spin_lock(&mm->page_table_lock);
- /*
- * If we find pgtable_page set, we return
- * the allocated page with single fragement
- * count.
- */
- if (likely(!mm->context.pte_frag)) {
- atomic_set(&page->pt_frag_refcount, PTE_FRAG_NR);
- mm->context.pte_frag = ret + PTE_FRAG_SIZE;
- }
- spin_unlock(&mm->page_table_lock);
-
- return (pte_t *)ret;
-}
-
-pte_t *pte_fragment_alloc(struct mm_struct *mm, unsigned long vmaddr, int kernel)
-{
- pte_t *pte;
-
- pte = get_pte_from_cache(mm);
- if (pte)
- return pte;
-
- return __alloc_for_ptecache(mm, kernel);
-}
-
-void pte_fragment_free(unsigned long *table, int kernel)
-{
- struct page *page = virt_to_page(table);
-
- BUG_ON(atomic_read(&page->pt_frag_refcount) <= 0);
- if (atomic_dec_and_test(&page->pt_frag_refcount)) {
- if (!kernel)
- pgtable_page_dtor(page);
- __free_page(page);
- }
-}
-
static inline void pgtable_free(void *table, int index)
{
switch (index) {
diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
new file mode 100644
index 000000000000..d61e7c2a9a79
--- /dev/null
+++ b/arch/powerpc/mm/pgtable-frag.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Handling Page Tables through page fragments
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/gfp.h>
+#include <linux/mm.h>
+#include <linux/percpu.h>
+#include <linux/hardirq.h>
+#include <linux/hugetlb.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/tlb.h>
+
+void pte_frag_destroy(void *pte_frag)
+{
+ int count;
+ struct page *page;
+
+ page = virt_to_page(pte_frag);
+ /* drop all the pending references */
+ count = ((unsigned long)pte_frag & ~PAGE_MASK) >> PTE_FRAG_SIZE_SHIFT;
+ /* We allow PTE_FRAG_NR fragments from a PTE page */
+ if (atomic_sub_and_test(PTE_FRAG_NR - count, &page->pt_frag_refcount)) {
+ pgtable_page_dtor(page);
+ __free_page(page);
+ }
+}
+
+static pte_t *get_pte_from_cache(struct mm_struct *mm)
+{
+ void *pte_frag, *ret;
+
+ spin_lock(&mm->page_table_lock);
+ ret = mm->context.pte_frag;
+ if (ret) {
+ pte_frag = ret + PTE_FRAG_SIZE;
+ /*
+ * If we have taken up all the fragments mark PTE page NULL
+ */
+ if (((unsigned long)pte_frag & ~PAGE_MASK) == 0)
+ pte_frag = NULL;
+ mm->context.pte_frag = pte_frag;
+ }
+ spin_unlock(&mm->page_table_lock);
+ return (pte_t *)ret;
+}
+
+static pte_t *__alloc_for_ptecache(struct mm_struct *mm, int kernel)
+{
+ void *ret = NULL;
+ struct page *page;
+
+ if (!kernel) {
+ page = alloc_page(PGALLOC_GFP | __GFP_ACCOUNT);
+ if (!page)
+ return NULL;
+ if (!pgtable_page_ctor(page)) {
+ __free_page(page);
+ return NULL;
+ }
+ } else {
+ page = alloc_page(PGALLOC_GFP);
+ if (!page)
+ return NULL;
+ }
+
+ atomic_set(&page->pt_frag_refcount, 1);
+
+ ret = page_address(page);
+ /*
+ * if we support only one fragment just return the
+ * allocated page.
+ */
+ if (PTE_FRAG_NR == 1)
+ return ret;
+ spin_lock(&mm->page_table_lock);
+ /*
+ * If we find pgtable_page set, we return
+ * the allocated page with single fragement
+ * count.
+ */
+ if (likely(!mm->context.pte_frag)) {
+ atomic_set(&page->pt_frag_refcount, PTE_FRAG_NR);
+ mm->context.pte_frag = ret + PTE_FRAG_SIZE;
+ }
+ spin_unlock(&mm->page_table_lock);
+
+ return (pte_t *)ret;
+}
+
+pte_t *pte_fragment_alloc(struct mm_struct *mm, unsigned long vmaddr, int kernel)
+{
+ pte_t *pte;
+
+ pte = get_pte_from_cache(mm);
+ if (pte)
+ return pte;
+
+ return __alloc_for_ptecache(mm, kernel);
+}
+
+void pte_fragment_free(unsigned long *table, int kernel)
+{
+ struct page *page = virt_to_page(table);
+
+ BUG_ON(atomic_read(&page->pt_frag_refcount) <= 0);
+ if (atomic_dec_and_test(&page->pt_frag_refcount)) {
+ if (!kernel)
+ pgtable_page_dtor(page);
+ __free_page(page);
+ }
+}
--
2.13.3
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