[PATCH 8/7] arm: Implement the new page table range API

Matthew Wilcox (Oracle)
2023-02-13T21:05:08Z

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

The PG_dcache_clear flag changes from being a per-page bit to being a
per-folio bit, which makes __dma_page_dev_to_cpu() a bit more exciting.
It also makes sense to add flush_cache_pages(), even though this isn't
used by generic code (yet?)

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
arch/arm/include/asm/cacheflush.h | 24 ++++---
arch/arm/include/asm/pgtable.h | 5 +-
arch/arm/include/asm/tlbflush.h | 13 ++--
arch/arm/mm/copypage-v4mc.c | 5 +-
arch/arm/mm/copypage-v6.c | 5 +-
arch/arm/mm/copypage-xscale.c | 5 +-
arch/arm/mm/dma-mapping.c | 24 +++----
arch/arm/mm/fault-armv.c | 14 ++---
arch/arm/mm/flush.c | 101 ++++++++++++++++++------------
arch/arm/mm/mm.h | 2 +-
arch/arm/mm/mmu.c | 14 +++--
11 files changed, 127 insertions(+), 85 deletions(-)

diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
index a094f964c869..841e268d2374 100644
--- a/arch/arm/include/asm/cacheflush.h
+++ b/arch/arm/include/asm/cacheflush.h
@@ -231,14 +231,15 @@ vivt_flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned
vma->vm_flags);
}

-static inline void
-vivt_flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
+static inline void vivt_flush_cache_pages(struct vm_area_struct *vma,
+ unsigned long user_addr, unsigned long pfn, unsigned int nr)
{
struct mm_struct *mm = vma->vm_mm;

if (!mm || cpumask_test_cpu(smp_processor_id(), mm_cpumask(mm))) {
unsigned long addr = user_addr & PAGE_MASK;
- __cpuc_flush_user_range(addr, addr + PAGE_SIZE, vma->vm_flags);
+ __cpuc_flush_user_range(addr, addr + nr * PAGE_SIZE,
+ vma->vm_flags);
}
}

@@ -247,15 +248,17 @@ vivt_flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsig
vivt_flush_cache_mm(mm)
#define flush_cache_range(vma,start,end) \
vivt_flush_cache_range(vma,start,end)
-#define flush_cache_page(vma,addr,pfn) \
- vivt_flush_cache_page(vma,addr,pfn)
+#define flush_cache_pages(vma, addr, pfn, nr) \
+ vivt_flush_cache_pages(vma, addr, pfn, nr)
#else
-extern void flush_cache_mm(struct mm_struct *mm);
-extern void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
-extern void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn);
+void flush_cache_mm(struct mm_struct *mm);
+void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
+void flush_cache_pages(struct vm_area_struct *vma, unsigned long user_addr,
+ unsigned long pfn, unsigned int nr);
#endif

#define flush_cache_dup_mm(mm) flush_cache_mm(mm)
+#define flush_cache_page(vma, addr, pfn) flush_cache_pages(vma, addr, pfn, 1)

/*
* flush_icache_user_range is used when we want to ensure that the
@@ -289,7 +292,9 @@ extern void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr
* See update_mmu_cache for the user space part.
*/
#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
-extern void flush_dcache_page(struct page *);
+void flush_dcache_page(struct page *);
+void flush_dcache_folio(struct folio *folio);
+#define flush_dcache_folio flush_dcache_folio

#define ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE 1
static inline void flush_kernel_vmap_range(void *addr, int size)
@@ -321,6 +326,7 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
* duplicate cache flushing elsewhere performed by flush_dcache_page().
*/
#define flush_icache_page(vma,page) do { } while (0)
+#define flush_icache_pages(vma, page, nr) do { } while (0)

/*
* flush_cache_vmap() is used when creating mappings (eg, via vmap,
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index a58ccbb406ad..6525ac82bd50 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -207,8 +207,9 @@ static inline void __sync_icache_dcache(pte_t pteval)
extern void __sync_icache_dcache(pte_t pteval);
#endif

-void set_pte_at(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pteval);
+void set_ptes(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pteval, unsigned int nr);
+#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)

static inline pte_t clear_pte_bit(pte_t pte, pgprot_t prot)
{
diff --git a/arch/arm/include/asm/tlbflush.h b/arch/arm/include/asm/tlbflush.h
index 0ccc985b90af..7d792e485f4f 100644
--- a/arch/arm/include/asm/tlbflush.h
+++ b/arch/arm/include/asm/tlbflush.h
@@ -619,18 +619,21 @@ extern void flush_bp_all(void);
* If PG_dcache_clean is not set for the page, we need to ensure that any
* cache entries for the kernels virtual memory range are written
* back to the page. On ARMv6 and later, the cache coherency is handled via
- * the set_pte_at() function.
+ * the set_ptes() function.
*/
#if __LINUX_ARM_ARCH__ < 6
-extern void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
- pte_t *ptep);
+void update_mmu_cache_range(struct vm_area_struct *vma, unsigned long addr,
+ pte_t *ptep, unsigned int nr);
#else
-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)
{
}
#endif

+#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)

#endif
diff --git a/arch/arm/mm/copypage-v4mc.c b/arch/arm/mm/copypage-v4mc.c
index f1da3b439b96..7ddd82b9fe8b 100644
--- a/arch/arm/mm/copypage-v4mc.c
+++ b/arch/arm/mm/copypage-v4mc.c
@@ -64,10 +64,11 @@ static void mc_copy_user_page(void *from, void *to)
void v4_mc_copy_user_highpage(struct page *to, struct page *from,
unsigned long vaddr, struct vm_area_struct *vma)
{
+ struct folio *src = page_folio(from);
void *kto = kmap_atomic(to);

- if (!test_and_set_bit(PG_dcache_clean, &from->flags))
- __flush_dcache_page(page_mapping_file(from), from);
+ if (!test_and_set_bit(PG_dcache_clean, &src->flags))
+ __flush_dcache_folio(folio_flush_mapping(src), src);

raw_spin_lock(&minicache_lock);

diff --git a/arch/arm/mm/copypage-v6.c b/arch/arm/mm/copypage-v6.c
index d8a115de5507..a1a71f36d850 100644
--- a/arch/arm/mm/copypage-v6.c
+++ b/arch/arm/mm/copypage-v6.c
@@ -69,11 +69,12 @@ static void discard_old_kernel_data(void *kto)
static void v6_copy_user_highpage_aliasing(struct page *to,
struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
{
+ struct folio *src = page_folio(from);
unsigned int offset = CACHE_COLOUR(vaddr);
unsigned long kfrom, kto;

- if (!test_and_set_bit(PG_dcache_clean, &from->flags))
- __flush_dcache_page(page_mapping_file(from), from);
+ if (!test_and_set_bit(PG_dcache_clean, &src->flags))
+ __flush_dcache_folio(folio_flush_mapping(src), src);

/* FIXME: not highmem safe */
discard_old_kernel_data(page_address(to));
diff --git a/arch/arm/mm/copypage-xscale.c b/arch/arm/mm/copypage-xscale.c
index bcb485620a05..f1e29d3e8193 100644
--- a/arch/arm/mm/copypage-xscale.c
+++ b/arch/arm/mm/copypage-xscale.c
@@ -84,10 +84,11 @@ static void mc_copy_user_page(void *from, void *to)
void xscale_mc_copy_user_highpage(struct page *to, struct page *from,
unsigned long vaddr, struct vm_area_struct *vma)
{
+ struct folio *src = page_folio(from);
void *kto = kmap_atomic(to);

- if (!test_and_set_bit(PG_dcache_clean, &from->flags))
- __flush_dcache_page(page_mapping_file(from), from);
+ if (!test_and_set_bit(PG_dcache_clean, &src->flags))
+ __flush_dcache_folio(folio_flush_mapping(src), src);

raw_spin_lock(&minicache_lock);

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 8bc01071474a..5ecfde41d70a 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -693,6 +693,7 @@ static void __dma_page_cpu_to_dev(struct page *page, unsigned long off,
static void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
size_t size, enum dma_data_direction dir)
{
+ struct folio *folio = page_folio(page);
phys_addr_t paddr = page_to_phys(page) + off;

/* FIXME: non-speculating: not required */
@@ -707,19 +708,18 @@ static void __dma_page_dev_to_cpu(struct page *page, unsigned long off,
* Mark the D-cache clean for these pages to avoid extra flushing.
*/
if (dir != DMA_TO_DEVICE && size >= PAGE_SIZE) {
- unsigned long pfn;
- size_t left = size;
-
- pfn = page_to_pfn(page) + off / PAGE_SIZE;
- off %= PAGE_SIZE;
- if (off) {
- pfn++;
- left -= PAGE_SIZE - off;
+ ssize_t left = size;
+ size_t offset = offset_in_folio(folio, paddr);
+
+ if (offset) {
+ left -= folio_size(folio) - offset;
+ folio = folio_next(folio);
}
- while (left >= PAGE_SIZE) {
- page = pfn_to_page(pfn++);
- set_bit(PG_dcache_clean, &page->flags);
- left -= PAGE_SIZE;
+
+ while (left >= (ssize_t)folio_size(folio)) {
+ set_bit(PG_dcache_clean, &folio->flags);
+ left -= folio_size(folio);
+ folio = folio_next(folio);
}
}
}
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index 0e49154454a6..e2c869b8f012 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -178,8 +178,8 @@ make_coherent(struct address_space *mapping, struct vm_area_struct *vma,
*
* Note that the pte lock will be held.
*/
-void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
- pte_t *ptep)
+void update_mmu_cache_range(struct vm_area_struct *vma, unsigned long addr,
+ pte_t *ptep, unsigned int nr)
{
unsigned long pfn = pte_pfn(*ptep);
struct address_space *mapping;
@@ -192,13 +192,13 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr,
* The zero page is never written to, so never has any dirty
* cache lines, and therefore never needs to be flushed.
*/
- page = pfn_to_page(pfn);
- if (page == ZERO_PAGE(0))
+ if (is_zero_pfn(pfn))
return;

- mapping = page_mapping_file(page);
- if (!test_and_set_bit(PG_dcache_clean, &page->flags))
- __flush_dcache_page(mapping, page);
+ folio = page_folio(pfn_to_page(pfn));
+ mapping = folio_flush_mapping(page);
+ if (!test_and_set_bit(PG_dcache_clean, &folio->flags))
+ __flush_dcache_folio(mapping, folio);
if (mapping) {
if (cache_is_vivt())
make_coherent(mapping, vma, addr, ptep, pfn);
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 7ff9feea13a6..b56a65626798 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -95,10 +95,10 @@ void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned
__flush_icache_all();
}

-void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn)
+void flush_cache_pages(struct vm_area_struct *vma, unsigned long user_addr, unsigned long pfn, unsigned int nr)
{
if (cache_is_vivt()) {
- vivt_flush_cache_page(vma, user_addr, pfn);
+ vivt_flush_cache_pages(vma, user_addr, pfn, nr);
return;
}

@@ -196,29 +196,31 @@ void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
#endif
}

-void __flush_dcache_page(struct address_space *mapping, struct page *page)
+void __flush_dcache_folio(struct address_space *mapping, struct folio *folio)
{
/*
* Writeback any data associated with the kernel mapping of this
* page. This ensures that data in the physical page is mutually
* coherent with the kernels mapping.
*/
- if (!PageHighMem(page)) {
- __cpuc_flush_dcache_area(page_address(page), page_size(page));
+ if (!folio_test_highmem(folio)) {
+ __cpuc_flush_dcache_area(folio_address(folio),
+ folio_size(folio));
} else {
unsigned long i;
if (cache_is_vipt_nonaliasing()) {
- for (i = 0; i < compound_nr(page); i++) {
- void *addr = kmap_atomic(page + i);
+ for (i = 0; i < folio_nr_pages(folio); i++) {
+ void *addr = kmap_local_folio(folio,
+ i * PAGE_SIZE);
__cpuc_flush_dcache_area(addr, PAGE_SIZE);
- kunmap_atomic(addr);
+ kunmap_local(addr);
}
} else {
- for (i = 0; i < compound_nr(page); i++) {
- void *addr = kmap_high_get(page + i);
+ for (i = 0; i < folio_nr_pages(folio); i++) {
+ void *addr = kmap_high_get(folio_page(folio, i));
if (addr) {
__cpuc_flush_dcache_area(addr, PAGE_SIZE);
- kunmap_high(page + i);
+ kunmap_high(folio_page(folio, i));
}
}
}
@@ -230,15 +232,14 @@ void __flush_dcache_page(struct address_space *mapping, struct page *page)
* userspace colour, which is congruent with page->index.
*/
if (mapping && cache_is_vipt_aliasing())
- flush_pfn_alias(page_to_pfn(page),
- page->index << PAGE_SHIFT);
+ flush_pfn_alias(folio_pfn(folio), folio_pos(folio));
}

-static void __flush_dcache_aliases(struct address_space *mapping, struct page *page)
+static void __flush_dcache_aliases(struct address_space *mapping, struct folio *folio)
{
struct mm_struct *mm = current->active_mm;
- struct vm_area_struct *mpnt;
- pgoff_t pgoff;
+ struct vm_area_struct *vma;
+ pgoff_t pgoff, pgoff_end;

/*
* There are possible user space mappings of this page:
@@ -246,21 +247,38 @@ static void __flush_dcache_aliases(struct address_space *mapping, struct page *p
* data in the current VM view associated with this page.
* - aliasing VIPT: we only need to find one mapping of this page.
*/
- pgoff = page->index;
+ pgoff = folio->index;
+ pgoff_end = pgoff + folio_nr_pages(folio) - 1;

flush_dcache_mmap_lock(mapping);
- vma_interval_tree_foreach(mpnt, &mapping->i_mmap, pgoff, pgoff) {
- unsigned long offset;
+ vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff_end) {
+ long offset;
+ unsigned long start, pfn;
+ unsigned int nr;

/*
* If this VMA is not in our MM, we can ignore it.
*/
- if (mpnt->vm_mm != mm)
+ if (vma->vm_mm != mm)
continue;
- if (!(mpnt->vm_flags & VM_MAYSHARE))
+ if (!(vma->vm_flags & VM_MAYSHARE))
continue;
- offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
- flush_cache_page(mpnt, mpnt->vm_start + offset, page_to_pfn(page));
+
+ start = vma->vm_start;
+ pfn = folio_pfn(folio);
+ nr = folio_nr_pages(folio);
+ offset = pgoff - vma->vm_pgoff;
+ if (offset < 0) {
+ pfn -= offset;
+ nr += offset;
+ start -= offset * PAGE_SIZE;
+ } else {
+ start += offset * PAGE_SIZE;
+ }
+ if (start + nr * PAGE_SIZE > vma->vm_end)
+ nr = (vma->vm_end - start) / PAGE_SIZE;
+
+ flush_cache_pages(vma, start, pfn, nr);
}
flush_dcache_mmap_unlock(mapping);
}
@@ -269,7 +287,7 @@ static void __flush_dcache_aliases(struct address_space *mapping, struct page *p
void __sync_icache_dcache(pte_t pteval)
{
unsigned long pfn;
- struct page *page;
+ struct folio *folio;
struct address_space *mapping;

if (cache_is_vipt_nonaliasing() && !pte_exec(pteval))
@@ -279,14 +297,14 @@ void __sync_icache_dcache(pte_t pteval)
if (!pfn_valid(pfn))
return;

- page = pfn_to_page(pfn);
+ folio = page_folio(pfn_to_page(pfn));
if (cache_is_vipt_aliasing())
- mapping = page_mapping_file(page);
+ mapping = folio_flush_mapping(folio);
else
mapping = NULL;

- if (!test_and_set_bit(PG_dcache_clean, &page->flags))
- __flush_dcache_page(mapping, page);
+ if (!test_and_set_bit(PG_dcache_clean, &folio->flags))
+ __flush_dcache_folio(mapping, folio);

if (pte_exec(pteval))
__flush_icache_all();
@@ -312,7 +330,7 @@ void __sync_icache_dcache(pte_t pteval)
* Note that we disable the lazy flush for SMP configurations where
* the cache maintenance operations are not automatically broadcasted.
*/
-void flush_dcache_page(struct page *page)
+void flush_dcache_folio(struct folio *folio)
{
struct address_space *mapping;

@@ -320,31 +338,36 @@ void flush_dcache_page(struct page *page)
* The zero page is never written to, so never has any dirty
* cache lines, and therefore never needs to be flushed.
*/
- if (page == ZERO_PAGE(0))
+ if (is_zero_pfn(folio_pfn(folio)))
return;

if (!cache_ops_need_broadcast() && cache_is_vipt_nonaliasing()) {
- if (test_bit(PG_dcache_clean, &page->flags))
- clear_bit(PG_dcache_clean, &page->flags);
+ if (test_bit(PG_dcache_clean, &folio->flags))
+ clear_bit(PG_dcache_clean, &folio->flags);
return;
}

- mapping = page_mapping_file(page);
+ mapping = folio_flush_mapping(folio);

if (!cache_ops_need_broadcast() &&
- mapping && !page_mapcount(page))
- clear_bit(PG_dcache_clean, &page->flags);
+ mapping && !folio_mapped(folio))
+ clear_bit(PG_dcache_clean, &folio->flags);
else {
- __flush_dcache_page(mapping, page);
+ __flush_dcache_folio(mapping, folio);
if (mapping && cache_is_vivt())
- __flush_dcache_aliases(mapping, page);
+ __flush_dcache_aliases(mapping, folio);
else if (mapping)
__flush_icache_all();
- set_bit(PG_dcache_clean, &page->flags);
+ set_bit(PG_dcache_clean, &folio->flags);
}
}
-EXPORT_SYMBOL(flush_dcache_page);
+EXPORT_SYMBOL(flush_dcache_folio);

+void flush_dcache_page(struct page *page)
+{
+ flush_dcache_folio(page_folio(page));
+}
+EXPORT_SYMBOL(flush_dcache_page);
/*
* Flush an anonymous page so that users of get_user_pages()
* can safely access the data. The expected sequence is:
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index d7ffccb7fea7..419316316711 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -45,7 +45,7 @@ struct mem_type {

const struct mem_type *get_mem_type(unsigned int type);

-extern void __flush_dcache_page(struct address_space *mapping, struct page *page);
+void __flush_dcache_folio(struct address_space *mapping, struct folio *folio);

/*
* ARM specific vm_struct->flags bits.
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 463fc2a8448f..9947bbc32b04 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1788,7 +1788,7 @@ void __init paging_init(const struct machine_desc *mdesc)
bootmem_init();

empty_zero_page = virt_to_page(zero_page);
- __flush_dcache_page(NULL, empty_zero_page);
+ __flush_dcache_folio(NULL, page_folio(empty_zero_page));
}

void __init early_mm_init(const struct machine_desc *mdesc)
@@ -1797,8 +1797,8 @@ void __init early_mm_init(const struct machine_desc *mdesc)
early_paging_init(mdesc);
}

-void set_pte_at(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pteval)
+void set_ptes(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pteval, unsigned int nr)
{
unsigned long ext = 0;

@@ -1808,5 +1808,11 @@ void set_pte_at(struct mm_struct *mm, unsigned long addr,
ext |= PTE_EXT_NG;
}

- set_pte_ext(ptep, pteval, ext);
+ for (;;) {
+ set_pte_ext(ptep, pteval, ext);
+ if (--nr == 0)
+ break;
+ ptep++;
+ pte_val(pteval) += PAGE_SIZE;
+ }
}
--
2.39.1