[PATCH 10/7] riscv: Implement the new page table range API

Matthew Wilcox (Oracle)
2023-02-15T00:05:29Z

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

The PG_dcache_clear flag changes from being a per-page bit to being a
per-folio bit.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
arch/riscv/include/asm/cacheflush.h | 19 +++++++++----------
arch/riscv/include/asm/pgtable.h | 25 ++++++++++++++++++-------
arch/riscv/mm/cacheflush.c | 11 ++---------
3 files changed, 29 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 13222fd5c4b4..03706c833e70 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 +415,10 @@ 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.
*/
- flush_tlb_page(vma, address);
+ flush_tlb_range(vma, address, 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 +458,21 @@ 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 3cc07ed45aeb..b725c3f6f57f 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_and_set_bit(PG_dcache_clean, &page->flags))
+ if (!test_and_set_bit(PG_dcache_clean, &folio->flags))
flush_icache_all();
}
#endif /* CONFIG_MMU */
--
2.39.1