Re: [PATCH v4 20/36] powerpc: Implement the new page table range API

[Matthew Wilcox <willy@infradead.org>]

On Wed, Mar 15, 2023 at 10:18:22AM +0000, Christophe Leroy wrote:
> I investigated a bit further and can confirm now that the above won't 
> always work, see comment 
> https://elixir.bootlin.com/linux/v6.3-rc2/source/arch/powerpc/include/asm/nohash/32/pgtable.h#L147
> 
> And then you see 
> https://elixir.bootlin.com/linux/v6.3-rc2/source/arch/powerpc/include/asm/nohash/pte-e500.h#L63

Got it.  Here's what I intend to fold in for the next version:

diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 7bf1fe7297c6..5f12b9382909 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -462,11 +462,6 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
 		     pgprot_val(pgprot));
 }
 
-static inline unsigned long pte_pfn(pte_t pte)
-{
-	return pte_val(pte) >> PTE_RPN_SHIFT;
-}
-
 /* Generic modifiers for PTE bits */
 static inline pte_t pte_wrprotect(pte_t pte)
 {
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 4acc9690f599..c5baa3082a5a 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -104,6 +104,7 @@
  * and every thing below PAGE_SHIFT;
  */
 #define PTE_RPN_MASK	(((1UL << _PAGE_PA_MAX) - 1) & (PAGE_MASK))
+#define PTE_RPN_SHIFT	PAGE_SHIFT
 /*
  * set of bits not changed in pmd_modify. Even though we have hash specific bits
  * in here, on radix we expect them to be zero.
@@ -569,11 +570,6 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
 	return __pte(((pte_basic_t)pfn << PAGE_SHIFT) | pgprot_val(pgprot) | _PAGE_PTE);
 }
 
-static inline unsigned long pte_pfn(pte_t pte)
-{
-	return (pte_val(pte) & PTE_RPN_MASK) >> PAGE_SHIFT;
-}
-
 /* Generic modifiers for PTE bits */
 static inline pte_t pte_wrprotect(pte_t pte)
 {
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index 69a7dd47a9f0..03be8b22aaea 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -101,8 +101,6 @@ static inline bool pte_access_permitted(pte_t pte, bool write)
 static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot) {
 	return __pte(((pte_basic_t)(pfn) << PTE_RPN_SHIFT) |
 		     pgprot_val(pgprot)); }
-static inline unsigned long pte_pfn(pte_t pte)	{
-	return pte_val(pte) >> PTE_RPN_SHIFT; }
 
 /* Generic modifiers for PTE bits */
 static inline pte_t pte_exprotect(pte_t pte)
@@ -279,7 +277,7 @@ static inline int pud_huge(pud_t pud)
 void update_mmu_cache_range(struct vm_area_struct *vma, unsigned long address,
 		pte_t *ptep, unsigned int nr);
 #else
-static inline void update_mmu_cache(struct vm_area_struct *vma,
+static inline void update_mmu_cache_range(struct vm_area_struct *vma,
 		unsigned long address, pte_t *ptep, unsigned int nr) {}
 #endif
 
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 656ecf2b10cd..491a2720f835 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -54,6 +54,12 @@ void set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
 /* Keep these as a macros to avoid include dependency mess */
 #define pte_page(x)		pfn_to_page(pte_pfn(x))
 #define mk_pte(page, pgprot)	pfn_pte(page_to_pfn(page), (pgprot))
+
+static inline unsigned long pte_pfn(pte_t pte)
+{
+	return (pte_val(pte) & PTE_RPN_MASK) >> PTE_RPN_SHIFT;
+}
+
 /*
  * Select all bits except the pfn
  */
diff --git a/arch/powerpc/mm/nohash/e500_hugetlbpage.c b/arch/powerpc/mm/nohash/e500_hugetlbpage.c
index f3cb91107a47..583b3098763f 100644
--- a/arch/powerpc/mm/nohash/e500_hugetlbpage.c
+++ b/arch/powerpc/mm/nohash/e500_hugetlbpage.c
@@ -178,7 +178,7 @@ 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,
+void update_mmu_cache_range(struct vm_area_struct *vma, unsigned long address,
 		pte_t *ptep, unsigned int nr)
 {
 	if (is_vm_hugetlb_page(vma))
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index b3c7b874a7a2..db236b494845 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -208,7 +208,7 @@ void set_ptes(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
 		if (--nr == 0)
 			break;
 		ptep++;
-		pte = __pte(pte_val(pte) + PAGE_SIZE);
+		pte = __pte(pte_val(pte) + (1UL << PTE_RPN_SHIFT));
 		addr += PAGE_SIZE;
 	}
 }