[tip: locking/kcsan] sparc32: mm: Change pgtable_t type to pte_t * instead of struct page *

["tip-bot2 for Will Deacon" <tip-bot2@linutronix.de>]

The following commit has been merged into the locking/kcsan branch of tip:

Commit-ID:     c95be5b549d6af16e1f9b9307f745ef78a01d11c
Gitweb:        https://git.kernel.org/tip/c95be5b549d6af16e1f9b9307f745ef78a01d11c
Author:        Will Deacon <will@kernel.org>
AuthorDate:    Mon, 11 May 2020 21:41:35 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Tue, 12 May 2020 11:04:09 +02:00

sparc32: mm: Change pgtable_t type to pte_t * instead of struct page *

Change the 'pgtable_t' type for sparc32 so that it represents the uncached
virtual address of the PTE table, rather than the underlying 'struct page'.

This allows to free page table allocations smaller than a page.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Link: https://lkml.kernel.org/r/20200511204150.27858-4-will@kernel.org

---
 arch/sparc/include/asm/page_32.h    |  2 +-
 arch/sparc/include/asm/pgalloc_32.h |  6 +++---
 arch/sparc/include/asm/pgtable_32.h | 11 +++++++++++-
 arch/sparc/mm/srmmu.c               | 29 ++++++++--------------------
 4 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/arch/sparc/include/asm/page_32.h b/arch/sparc/include/asm/page_32.h
index da01c8c..fff8861 100644
--- a/arch/sparc/include/asm/page_32.h
+++ b/arch/sparc/include/asm/page_32.h
@@ -106,7 +106,7 @@ typedef unsigned long iopgprot_t;
 
 #endif
 
-typedef struct page *pgtable_t;
+typedef pte_t *pgtable_t;
 
 #define TASK_UNMAPPED_BASE	0x50000000
 
diff --git a/arch/sparc/include/asm/pgalloc_32.h b/arch/sparc/include/asm/pgalloc_32.h
index 99c0324..b772384 100644
--- a/arch/sparc/include/asm/pgalloc_32.h
+++ b/arch/sparc/include/asm/pgalloc_32.h
@@ -50,11 +50,11 @@ static inline void free_pmd_fast(pmd_t * pmd)
 #define pmd_free(mm, pmd)		free_pmd_fast(pmd)
 #define __pmd_free_tlb(tlb, pmd, addr)	pmd_free((tlb)->mm, pmd)
 
-void pmd_populate(struct mm_struct *mm, pmd_t *pmdp, struct page *ptep);
-#define pmd_pgtable(pmd) pmd_page(pmd)
+#define pmd_populate(mm, pmd, pte)	pmd_set(pmd, pte)
+#define pmd_pgtable(pmd)		(pgtable_t)__pmd_page(pmd)
 
 void pmd_set(pmd_t *pmdp, pte_t *ptep);
-#define pmd_populate_kernel(MM, PMD, PTE) pmd_set(PMD, PTE)
+#define pmd_populate_kernel		pmd_populate
 
 pgtable_t pte_alloc_one(struct mm_struct *mm);
 
diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index 3367e2b..c5625b2 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h
@@ -135,6 +135,17 @@ static inline struct page *pmd_page(pmd_t pmd)
 	return pfn_to_page((pmd_val(pmd) & SRMMU_PTD_PMASK) >> (PAGE_SHIFT-4));
 }
 
+static inline unsigned long __pmd_page(pmd_t pmd)
+{
+	unsigned long v;
+
+	if (srmmu_device_memory(pmd_val(pmd)))
+		BUG();
+
+	v = pmd_val(pmd) & SRMMU_PTD_PMASK;
+	return (unsigned long)__nocache_va(v << 4);
+}
+
 static inline unsigned long pud_page_vaddr(pud_t pud)
 {
 	if (srmmu_device_memory(pud_val(pud))) {
diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index 50da4bc..c861c0f 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -140,12 +140,6 @@ void pmd_set(pmd_t *pmdp, pte_t *ptep)
 	set_pte((pte_t *)&pmd_val(*pmdp), __pte(SRMMU_ET_PTD | ptp));
 }
 
-void pmd_populate(struct mm_struct *mm, pmd_t *pmdp, struct page *ptep)
-{
-	unsigned long ptp = page_to_pfn(ptep) << (PAGE_SHIFT-4); /* watch for overflow */
-	set_pte((pte_t *)&pmd_val(*pmdp), __pte(SRMMU_ET_PTD | ptp));
-}
-
 /* Find an entry in the third-level page table.. */
 pte_t *pte_offset_kernel(pmd_t *dir, unsigned long address)
 {
@@ -364,31 +358,26 @@ pgd_t *get_pgd_fast(void)
  */
 pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
-	unsigned long pte;
+	pte_t *ptep;
 	struct page *page;
 
-	if ((pte = (unsigned long)pte_alloc_one_kernel(mm)) == 0)
+	if ((ptep = pte_alloc_one_kernel(mm)) == 0)
 		return NULL;
-	page = pfn_to_page(__nocache_pa(pte) >> PAGE_SHIFT);
+	page = pfn_to_page(__nocache_pa((unsigned long)ptep) >> PAGE_SHIFT);
 	if (!pgtable_pte_page_ctor(page)) {
 		__free_page(page);
 		return NULL;
 	}
-	return page;
+	return ptep;
 }
 
-void pte_free(struct mm_struct *mm, pgtable_t pte)
+void pte_free(struct mm_struct *mm, pgtable_t ptep)
 {
-	unsigned long p;
-
-	pgtable_pte_page_dtor(pte);
-	p = (unsigned long)page_address(pte);	/* Cached address (for test) */
-	if (p == 0)
-		BUG();
-	p = page_to_pfn(pte) << PAGE_SHIFT;	/* Physical address */
+	struct page *page;
 
-	/* free non cached virtual address*/
-	srmmu_free_nocache(__nocache_va(p), SRMMU_PTE_TABLE_SIZE);
+	page = pfn_to_page(__nocache_pa((unsigned long)ptep) >> PAGE_SHIFT);
+	pgtable_pte_page_dtor(page);
+	srmmu_free_nocache(ptep, SRMMU_PTE_TABLE_SIZE);
 }
 
 /* context handling - a dynamically sized pool is used */