linux-kernel - [PATCH v3 20/34] riscv: Implement the new page table range API

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Message-Id: <20230228213738.272178-21-willy@infradead.org>
Date:   Tue, 28 Feb 2023 21:37:23 +0000
From:   "Matthew Wilcox (Oracle)" <willy@...radead.org>
To:     linux-mm@...ck.org, linux-arch@...r.kernel.org
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        linux-kernel@...r.kernel.org,
        Alexandre Ghiti <alexghiti@...osinc.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-riscv@...ts.infradead.org
Subject: [PATCH v3 20/34] riscv: Implement the new page table range API

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

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Reviewed-by: Alexandre Ghiti <alexghiti@...osinc.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>
Cc: Palmer Dabbelt <palmer@...belt.com>
Cc: Albert Ou <aou@...s.berkeley.edu>
Cc: linux-riscv@...ts.infradead.org
---
 arch/riscv/include/asm/cacheflush.h | 19 +++++++++----------
 arch/riscv/include/asm/pgtable.h    | 26 +++++++++++++++++++-------
 arch/riscv/mm/cacheflush.c          | 11 ++---------
 3 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/arch/riscv/include/asm/cacheflush.h b/arch/riscv/include/asm/cacheflush.h
index 03e3b95ae6da..10e5e96f09b5 100644
--- a/arch/riscv/include/asm/cacheflush.h
+++ b/arch/riscv/include/asm/cacheflush.h
@@ -15,20 +15,19 @@ static inline void local_flush_icache_all(void)
 
 #define PG_dcache_clean PG_arch_1
 
-static inline void flush_dcache_page(struct page *page)
+static inline 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 flush_icache_pte()).
-	 */
-	if (PageHuge(page))
-		page = compound_head(page);
-
-	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);
 }
+#define flush_dcache_folio flush_dcache_folio
 #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
 
+static inline void flush_dcache_page(struct page *page)
+{
+	flush_dcache_folio(page_folio(page));
+}
+
 /*
  * RISC-V doesn't have an instruction to flush parts of the instruction cache,
  * so instead we just flush the whole thing.
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index b516f3b59616..3a3a776fc047 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -405,8 +405,8 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 
 
 /* Commit new configuration to MMU hardware */
-static inline void update_mmu_cache(struct vm_area_struct *vma,
-	unsigned long address, pte_t *ptep)
+static inline void update_mmu_cache_range(struct vm_area_struct *vma,
+		unsigned long address, pte_t *ptep, unsigned int nr)
 {
 	/*
 	 * The kernel assumes that TLBs don't cache invalid entries, but
@@ -415,8 +415,11 @@ static inline void update_mmu_cache(struct vm_area_struct *vma,
 	 * Relying on flush_tlb_fix_spurious_fault would suffice, but
 	 * the extra traps reduce performance.  So, eagerly SFENCE.VMA.
 	 */
-	local_flush_tlb_page(address);
+	while (nr--)
+		local_flush_tlb_page(address + nr * PAGE_SIZE);
 }
+#define update_mmu_cache(vma, addr, ptep) \
+	update_mmu_cache_range(vma, addr, ptep, 1)
 
 #define __HAVE_ARCH_UPDATE_MMU_TLB
 #define update_mmu_tlb update_mmu_cache
@@ -456,12 +459,21 @@ static inline void __set_pte_at(struct mm_struct *mm,
 	set_pte(ptep, pteval);
 }
 
-static inline void set_pte_at(struct mm_struct *mm,
-	unsigned long addr, pte_t *ptep, pte_t pteval)
+static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
+		pte_t *ptep, pte_t pteval, unsigned int nr)
 {
-	page_table_check_ptes_set(mm, addr, ptep, pteval, 1);
-	__set_pte_at(mm, addr, ptep, pteval);
+	page_table_check_ptes_set(mm, addr, ptep, pteval, nr);
+
+	for (;;) {
+		__set_pte_at(mm, addr, ptep, pteval);
+		if (--nr == 0)
+			break;
+		ptep++;
+		addr += PAGE_SIZE;
+		pte_val(pteval) += 1 << _PAGE_PFN_SHIFT;
+	}
 }
+#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
 
 static inline void pte_clear(struct mm_struct *mm,
 	unsigned long addr, pte_t *ptep)
diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index fcd6145fbead..e36a851e5788 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -81,16 +81,9 @@ void flush_icache_mm(struct mm_struct *mm, bool local)
 #ifdef CONFIG_MMU
 void flush_icache_pte(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)) {
+	if (!test_bit(PG_dcache_clean, &folio->flags)) {
 		flush_icache_all();
 		set_bit(PG_dcache_clean, &page->flags);
 	}
-- 
2.39.1