On Mon, Feb 27, 2023 at 07:45:08PM +0000, Christophe Leroy wrote:

Hi,

Le 27/02/2023 à 18:57, Matthew Wilcox (Oracle) a écrit :

quoted

Add set_ptes(), update_mmu_cache_range() and flush_dcache_folio().
Change the PG_arch_1 (aka PG_dcache_dirty) flag from being per-page to
per-folio.

I'm unsure about my merging of flush_dcache_icache_hugepage() and
flush_dcache_icache_page() into flush_dcache_icache_folio() and subsequent
removal of flush_dcache_icache_phys().  Please review.

Not sure why you want to remove flush_dcache_icache_phys().

Well, I didn't, necessarily.  It's just that when I merged
flush_dcache_icache_hugepage() and flush_dcache_icache_page()
together, it was left with no callers.

Allthough that's only feasible when address bus is not wider than 32 
bits and cannot be done on BOOKE as you can't switch off MMU on BOOKE, 
flush_dcache_icache_phys() allows to flush not mapped pages without 
having to map them. So it is more efficient.

And it was just never done for the hugepage case?

quoted

@@ -148,17 +103,20 @@ static void __flush_dcache_icache(void *p)
  	invalidate_icache_range(addr, addr + PAGE_SIZE);
  }
  
-static void flush_dcache_icache_hugepage(struct page *page)
+void flush_dcache_icache_folio(struct folio *folio)
  {
-	int i;
-	int nr = compound_nr(page);
+	unsigned int i, nr = folio_nr_pages(folio);
  
-	if (!PageHighMem(page)) {
+	if (flush_coherent_icache())
+		return;
+
+	if (!folio_test_highmem(folio)) {
+		void *addr = folio_address(folio);
  		for (i = 0; i < nr; i++)
-			__flush_dcache_icache(lowmem_page_address(page + i));
+			__flush_dcache_icache(addr + i * PAGE_SIZE);
  	} else {
  		for (i = 0; i < nr; i++) {
-			void *start = kmap_local_page(page + i);
+			void *start = kmap_local_folio(folio, i * PAGE_SIZE);
  
  			__flush_dcache_icache(start);
  			kunmap_local(start);

So you'd like this to be:

	} else if (IS_ENABLED(CONFIG_BOOKE) || sizeof(phys_addr_t) > sizeof(void *)) {
		for (i = 0; i < nr; i++) {
			 void *start = kmap_local_folio(folio, i * PAGE_SIZE);
			 __flush_dcache_icache(start);
			 kunmap_local(start);
		}
	} else {
		unsigned long pfn = folio_pfn(folio);
		for (i = 0; i < nr; i++)
			flush_dcache_icache_phys((pfn + i) * PAGE_SIZE;
	}

(or maybe you'd prefer a flush_dcache_icache_pfn() that doesn't need to
worry about PAGE_MASK).

quoted

@@ -166,27 +124,6 @@ static void flush_dcache_icache_hugepage(struct page *page)
  	}
  }
  
-void flush_dcache_icache_page(struct page *page)
-{
-	if (flush_coherent_icache())
-		return;
-
-	if (PageCompound(page))
-		return flush_dcache_icache_hugepage(page);
-
-	if (!PageHighMem(page)) {
-		__flush_dcache_icache(lowmem_page_address(page));
-	} else if (IS_ENABLED(CONFIG_BOOKE) || sizeof(phys_addr_t) > sizeof(void *)) {
-		void *start = kmap_local_page(page);
-
-		__flush_dcache_icache(start);
-		kunmap_local(start);
-	} else {
-		flush_dcache_icache_phys(page_to_phys(page));
-	}
-}
-EXPORT_SYMBOL(flush_dcache_icache_page);
-
  void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
  {
  	clear_page(page);

diff --git a/arch/powerpc/mm/nohash/e500_hugetlbpage.c b/arch/powerpc/mm/nohash/e500_hugetlbpage.c
index 58c8d9849cb1..f3cb91107a47 100644
--- a/arch/powerpc/mm/nohash/e500_hugetlbpage.c
+++ b/arch/powerpc/mm/nohash/e500_hugetlbpage.c

@@ -178,7 +178,8 @@ book3e_hugetlb_preload(struct vm_area_struct *vma, unsigned long ea, pte_t pte)
   *
   * This must always be called with the pte lock held.
   */
-void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep)
+void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
+		pte_t *ptep, unsigned int nr)
  {
  	if (is_vm_hugetlb_page(vma))
  		book3e_hugetlb_preload(vma, address, *ptep);

diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index cb2dcdb18f8e..b3c7b874a7a2 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c

@@ -58,7 +58,7 @@ static inline int pte_looks_normal(pte_t pte)
  	return 0;
  }
  
-static struct page *maybe_pte_to_page(pte_t pte)
+static struct folio *maybe_pte_to_folio(pte_t pte)
  {
  	unsigned long pfn = pte_pfn(pte);
  	struct page *page;

@@ -68,7 +68,7 @@ static struct page *maybe_pte_to_page(pte_t pte)
  	page = pfn_to_page(pfn);
  	if (PageReserved(page))
  		return NULL;
-	return page;
+	return page_folio(page);
  }
  
  #ifdef CONFIG_PPC_BOOK3S

@@ -84,12 +84,12 @@ static pte_t set_pte_filter_hash(pte_t pte)
  	pte = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
  	if (pte_looks_normal(pte) && !(cpu_has_feature(CPU_FTR_COHERENT_ICACHE) ||
  				       cpu_has_feature(CPU_FTR_NOEXECUTE))) {
-		struct page *pg = maybe_pte_to_page(pte);
-		if (!pg)
+		struct folio *folio = maybe_pte_to_folio(pte);
+		if (!folio)
  			return pte;
-		if (!test_bit(PG_dcache_clean, &pg->flags)) {
-			flush_dcache_icache_page(pg);
-			set_bit(PG_dcache_clean, &pg->flags);
+		if (!test_bit(PG_dcache_clean, &folio->flags)) {
+			flush_dcache_icache_folio(folio);
+			set_bit(PG_dcache_clean, &folio->flags);
  		}
  	}
  	return pte;

@@ -107,7 +107,7 @@ static pte_t set_pte_filter_hash(pte_t pte) { return pte; }
   */
  static inline pte_t set_pte_filter(pte_t pte)
  {
-	struct page *pg;
+	struct folio *folio;
  
  	if (radix_enabled())
  		return pte;

@@ -120,18 +120,18 @@ static inline pte_t set_pte_filter(pte_t pte)
  		return pte;
  
  	/* If you set _PAGE_EXEC on weird pages you're on your own */
-	pg = maybe_pte_to_page(pte);
-	if (unlikely(!pg))
+	folio = maybe_pte_to_folio(pte);
+	if (unlikely(!folio))
  		return pte;
  
  	/* If the page clean, we move on */
-	if (test_bit(PG_dcache_clean, &pg->flags))
+	if (test_bit(PG_dcache_clean, &folio->flags))
  		return pte;
  
  	/* If it's an exec fault, we flush the cache and make it clean */
  	if (is_exec_fault()) {
-		flush_dcache_icache_page(pg);
-		set_bit(PG_dcache_clean, &pg->flags);
+		flush_dcache_icache_folio(folio);
+		set_bit(PG_dcache_clean, &folio->flags);
  		return pte;
  	}
  

@@ -142,7 +142,7 @@ static inline pte_t set_pte_filter(pte_t pte)
  static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma,
  				     int dirty)
  {
-	struct page *pg;
+	struct folio *folio;
  
  	if (IS_ENABLED(CONFIG_PPC_BOOK3S_64))
  		return pte;

@@ -168,17 +168,17 @@ static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma,
  #endif /* CONFIG_DEBUG_VM */
  
  	/* If you set _PAGE_EXEC on weird pages you're on your own */
-	pg = maybe_pte_to_page(pte);
-	if (unlikely(!pg))
+	folio = maybe_pte_to_folio(pte);
+	if (unlikely(!folio))
  		goto bail;
  
  	/* If the page is already clean, we move on */
-	if (test_bit(PG_dcache_clean, &pg->flags))
+	if (test_bit(PG_dcache_clean, &folio->flags))
  		goto bail;
  
  	/* Clean the page and set PG_dcache_clean */
-	flush_dcache_icache_page(pg);
-	set_bit(PG_dcache_clean, &pg->flags);
+	flush_dcache_icache_folio(folio);
+	set_bit(PG_dcache_clean, &folio->flags);
  
   bail:
  	return pte_mkexec(pte);

@@ -187,8 +187,8 @@ static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma,
  /*
   * set_pte stores a linux PTE into the linux page table.
   */
-void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
-		pte_t pte)
+void set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
+		pte_t pte, unsigned int nr)
  {
  	/*
  	 * Make sure hardware valid bit is not set. We don't do

@@ -203,7 +203,14 @@ void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
  	pte = set_pte_filter(pte);
  
  	/* Perform the setting of the PTE */
-	__set_pte_at(mm, addr, ptep, pte, 0);
+	for (;;) {
+		__set_pte_at(mm, addr, ptep, pte, 0);
+		if (--nr == 0)
+			break;
+		ptep++;
+		pte = __pte(pte_val(pte) + PAGE_SIZE);
+		addr += PAGE_SIZE;
+	}
  }
  
  void unmap_kernel_page(unsigned long va)