[PATCH 9/7] arm64: Implement the new page table range API

Matthew Wilcox (Oracle)
2023-02-15T00:05:23Z

Add set_ptes(), update_mmu_cache_range() and flush_dcache_folio().

The PG_dcache_clear flag changes from being a per-page bit to being a
per-folio bit.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
arch/arm64/include/asm/cacheflush.h | 4 +++-
arch/arm64/include/asm/pgtable.h | 25 ++++++++++++++------
arch/arm64/mm/flush.c | 36 +++++++++++------------------
3 files changed, 35 insertions(+), 30 deletions(-)

diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index 37185e978aeb..d115451ed263 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -114,7 +114,7 @@ extern void copy_to_user_page(struct vm_area_struct *, struct page *,
#define copy_to_user_page copy_to_user_page

/*
- * flush_dcache_page is used when the kernel has written to the page
+ * flush_dcache_folio is used when the kernel has written to the page
* cache page at virtual address page->virtual.
*
* If this page isn't mapped (ie, page_mapping == NULL), or it might
@@ -127,6 +127,8 @@ extern void copy_to_user_page(struct vm_area_struct *, struct page *,
*/
#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
extern void flush_dcache_page(struct page *);
+void flush_dcache_folio(struct folio *);
+#define flush_dcache_folio flush_dcache_folio

static __always_inline void icache_inval_all_pou(void)
{
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 69765dc697af..4d1b79dbff16 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -355,12 +355,21 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
set_pte(ptep, pte);
}

-static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pte)
-{
- page_table_check_ptes_set(mm, addr, ptep, pte, 1);
- return __set_pte_at(mm, addr, ptep, pte);
+static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte, unsigned int nr)
+{
+ page_table_check_ptes_set(mm, addr, ptep, pte, nr);
+
+ for (;;) {
+ __set_pte_at(mm, addr, ptep, pte);
+ if (--nr == 0)
+ break;
+ ptep++;
+ addr += PAGE_SIZE;
+ pte_val(pte) += PAGE_SIZE;
+ }
}
+#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)

/*
* Huge pte definitions.
@@ -1059,8 +1068,8 @@ static inline void arch_swap_restore(swp_entry_t entry, struct folio *folio)
/*
* On AArch64, the cache coherency is handled via the set_pte_at() function.
*/
-static inline void update_mmu_cache(struct vm_area_struct *vma,
- unsigned long addr, pte_t *ptep)
+static inline void update_mmu_cache_range(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep, unsigned int nr)
{
/*
* We don't do anything here, so there's a very small chance of
@@ -1069,6 +1078,8 @@ static inline void update_mmu_cache(struct vm_area_struct *vma,
*/
}

+#define update_mmu_cache(vma, addr, ptep) \
+ update_mmu_cache_range(vma, addr, ptep, 1)
#define update_mmu_cache_pmd(vma, address, pmd) do { } while (0)

#ifdef CONFIG_ARM64_PA_BITS_52
diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index 5f9379b3c8c8..deb781af0a3a 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -50,20 +50,13 @@ void copy_to_user_page(struct vm_area_struct *vma, struct page *page,

void __sync_icache_dcache(pte_t pte)
{
- struct page *page = pte_page(pte);
+ struct folio *folio = page_folio(pte_page(pte));

- /*
- * HugeTLB pages are always fully mapped, so only setting head page's
- * PG_dcache_clean flag is enough.
- */
- if (PageHuge(page))
- page = compound_head(page);
-
- if (!test_bit(PG_dcache_clean, &page->flags)) {
- sync_icache_aliases((unsigned long)page_address(page),
- (unsigned long)page_address(page) +
- page_size(page));
- set_bit(PG_dcache_clean, &page->flags);
+ if (!test_bit(PG_dcache_clean, &folio->flags)) {
+ sync_icache_aliases((unsigned long)folio_address(folio),
+ (unsigned long)folio_address(folio) +
+ folio_size(folio));
+ set_bit(PG_dcache_clean, &folio->flags);
}
}
EXPORT_SYMBOL_GPL(__sync_icache_dcache);
@@ -73,17 +66,16 @@ EXPORT_SYMBOL_GPL(__sync_icache_dcache);
* it as dirty for later flushing when mapped in user space (if executable,
* see __sync_icache_dcache).
*/
-void flush_dcache_page(struct page *page)
+void flush_dcache_folio(struct folio *folio)
{
- /*
- * HugeTLB pages are always fully mapped and only head page will be
- * set PG_dcache_clean (see comments in __sync_icache_dcache()).
- */
- if (PageHuge(page))
- page = compound_head(page);
+ if (test_bit(PG_dcache_clean, &folio->flags))
+ clear_bit(PG_dcache_clean, &folio->flags);
+}
+EXPORT_SYMBOL(flush_dcache_folio);

- if (test_bit(PG_dcache_clean, &page->flags))
- clear_bit(PG_dcache_clean, &page->flags);
+void flush_dcache_page(struct page *page)
+{
+ flush_dcache_folio(page_folio(page));
}
EXPORT_SYMBOL(flush_dcache_page);

--
2.39.1