Re: [PATCH v4 28/36] xtensa: Implement the new page table range API

[Mike Rapoport <rppt@kernel.org>]

On Wed, Mar 15, 2023 at 05:14:36AM +0000, Matthew Wilcox (Oracle) wrote:
> Add PFN_PTE_SHIFT, update_mmu_cache_range(), flush_dcache_folio() and
> flush_icache_pages().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Cc: Max Filippov <jcmvbkbc@gmail.com>
> Cc: linux-xtensa@linux-xtensa.org

Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
>  arch/xtensa/include/asm/cacheflush.h |  9 ++-
>  arch/xtensa/include/asm/pgtable.h    | 17 +++---
>  arch/xtensa/mm/cache.c               | 83 ++++++++++++++++------------
>  3 files changed, 62 insertions(+), 47 deletions(-)
> 
> diff --git a/arch/xtensa/include/asm/cacheflush.h b/arch/xtensa/include/asm/cacheflush.h
> index 7b4359312c25..35153f6725e4 100644
> --- a/arch/xtensa/include/asm/cacheflush.h
> +++ b/arch/xtensa/include/asm/cacheflush.h
> @@ -119,8 +119,14 @@ void flush_cache_page(struct vm_area_struct*,
>  #define flush_cache_vmap(start,end)	flush_cache_all()
>  #define flush_cache_vunmap(start,end)	flush_cache_all()
>  
> +void flush_dcache_folio(struct folio *folio);
> +#define flush_dcache_folio flush_dcache_folio
> +
>  #define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
> -void flush_dcache_page(struct page *);
> +static inline void flush_dcache_page(struct page *page)
> +{
> +	flush_dcache_folio(page_folio(page));
> +}
>  
>  void local_flush_cache_range(struct vm_area_struct *vma,
>  		unsigned long start, unsigned long end);
> @@ -156,6 +162,7 @@ void local_flush_cache_page(struct vm_area_struct *vma,
>  
>  /* This is not required, see Documentation/core-api/cachetlb.rst */
>  #define	flush_icache_page(vma,page)			do { } while (0)
> +#define	flush_icache_pages(vma, page, nr)		do { } while (0)
>  
>  #define flush_dcache_mmap_lock(mapping)			do { } while (0)
>  #define flush_dcache_mmap_unlock(mapping)		do { } while (0)
> diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
> index fc7a14884c6c..80bc70251aad 100644
> --- a/arch/xtensa/include/asm/pgtable.h
> +++ b/arch/xtensa/include/asm/pgtable.h
> @@ -274,6 +274,7 @@ static inline pte_t pte_mkwrite(pte_t pte)
>   * and a page entry and page directory to the page they refer to.
>   */
>  
> +#define PFN_PTE_SHIFT		PAGE_SHIFT
>  #define pte_pfn(pte)		(pte_val(pte) >> PAGE_SHIFT)
>  #define pte_same(a,b)		(pte_val(a) == pte_val(b))
>  #define pte_page(x)		pfn_to_page(pte_pfn(x))
> @@ -301,15 +302,9 @@ static inline void update_pte(pte_t *ptep, pte_t pteval)
>  
>  struct mm_struct;
>  
> -static inline void
> -set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval)
> -{
> -	update_pte(ptep, pteval);
> -}
> -
> -static inline void set_pte(pte_t *ptep, pte_t pteval)
> +static inline void set_pte(pte_t *ptep, pte_t pte)
>  {
> -	update_pte(ptep, pteval);
> +	update_pte(ptep, pte);
>  }
>  
>  static inline void
> @@ -407,8 +402,10 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte)
>  
>  #else
>  
> -extern  void update_mmu_cache(struct vm_area_struct * vma,
> -			      unsigned long address, pte_t *ptep);
> +void update_mmu_cache_range(struct vm_area_struct *vma,
> +		unsigned long address, pte_t *ptep, unsigned int nr);
> +#define update_mmu_cache(vma, address, ptep) \
> +	update_mmu_cache_range(vma, address, ptep, 1)
>  
>  typedef pte_t *pte_addr_t;
>  
> diff --git a/arch/xtensa/mm/cache.c b/arch/xtensa/mm/cache.c
> index 19e5a478a7e8..27bd798e4d89 100644
> --- a/arch/xtensa/mm/cache.c
> +++ b/arch/xtensa/mm/cache.c
> @@ -121,9 +121,9 @@ EXPORT_SYMBOL(copy_user_highpage);
>   *
>   */
>  
> -void flush_dcache_page(struct page *page)
> +void flush_dcache_folio(struct folio *folio)
>  {
> -	struct address_space *mapping = page_mapping_file(page);
> +	struct address_space *mapping = folio_flush_mapping(folio);
>  
>  	/*
>  	 * If we have a mapping but the page is not mapped to user-space
> @@ -132,14 +132,14 @@ void flush_dcache_page(struct page *page)
>  	 */
>  
>  	if (mapping && !mapping_mapped(mapping)) {
> -		if (!test_bit(PG_arch_1, &page->flags))
> -			set_bit(PG_arch_1, &page->flags);
> +		if (!test_bit(PG_arch_1, &folio->flags))
> +			set_bit(PG_arch_1, &folio->flags);
>  		return;
>  
>  	} else {
> -
> -		unsigned long phys = page_to_phys(page);
> -		unsigned long temp = page->index << PAGE_SHIFT;
> +		unsigned long phys = folio_pfn(folio) * PAGE_SIZE;
> +		unsigned long temp = folio_pos(folio);
> +		unsigned int i, nr = folio_nr_pages(folio);
>  		unsigned long alias = !(DCACHE_ALIAS_EQ(temp, phys));
>  		unsigned long virt;
>  
> @@ -154,22 +154,26 @@ void flush_dcache_page(struct page *page)
>  			return;
>  
>  		preempt_disable();
> -		virt = TLBTEMP_BASE_1 + (phys & DCACHE_ALIAS_MASK);
> -		__flush_invalidate_dcache_page_alias(virt, phys);
> +		for (i = 0; i < nr; i++) {
> +			virt = TLBTEMP_BASE_1 + (phys & DCACHE_ALIAS_MASK);
> +			__flush_invalidate_dcache_page_alias(virt, phys);
>  
> -		virt = TLBTEMP_BASE_1 + (temp & DCACHE_ALIAS_MASK);
> +			virt = TLBTEMP_BASE_1 + (temp & DCACHE_ALIAS_MASK);
>  
> -		if (alias)
> -			__flush_invalidate_dcache_page_alias(virt, phys);
> +			if (alias)
> +				__flush_invalidate_dcache_page_alias(virt, phys);
>  
> -		if (mapping)
> -			__invalidate_icache_page_alias(virt, phys);
> +			if (mapping)
> +				__invalidate_icache_page_alias(virt, phys);
> +			phys += PAGE_SIZE;
> +			temp += PAGE_SIZE;
> +		}
>  		preempt_enable();
>  	}
>  
>  	/* There shouldn't be an entry in the cache for this page anymore. */
>  }
> -EXPORT_SYMBOL(flush_dcache_page);
> +EXPORT_SYMBOL(flush_dcache_folio);
>  
>  /*
>   * For now, flush the whole cache. FIXME??
> @@ -207,45 +211,52 @@ EXPORT_SYMBOL(local_flush_cache_page);
>  
>  #endif /* DCACHE_WAY_SIZE > PAGE_SIZE */
>  
> -void
> -update_mmu_cache(struct vm_area_struct * vma, unsigned long addr, pte_t *ptep)
> +void update_mmu_cache_range(struct vm_area_struct *vma, unsigned long addr,
> +		pte_t *ptep, unsigned int nr)
>  {
>  	unsigned long pfn = pte_pfn(*ptep);
> -	struct page *page;
> +	struct folio *folio;
> +	unsigned int i;
>  
>  	if (!pfn_valid(pfn))
>  		return;
>  
> -	page = pfn_to_page(pfn);
> +	folio = page_folio(pfn_to_page(pfn));
>  
> -	/* Invalidate old entry in TLBs */
> -
> -	flush_tlb_page(vma, addr);
> +	/* Invalidate old entries in TLBs */
> +	for (i = 0; i < nr; i++)
> +		flush_tlb_page(vma, addr + i * PAGE_SIZE);
> +	nr = folio_nr_pages(folio);
>  
>  #if (DCACHE_WAY_SIZE > PAGE_SIZE)
>  
> -	if (!PageReserved(page) && test_bit(PG_arch_1, &page->flags)) {
> -		unsigned long phys = page_to_phys(page);
> +	if (!folio_test_reserved(folio) && test_bit(PG_arch_1, &folio->flags)) {
> +		unsigned long phys = folio_pfn(folio) * PAGE_SIZE;
>  		unsigned long tmp;
>  
>  		preempt_disable();
> -		tmp = TLBTEMP_BASE_1 + (phys & DCACHE_ALIAS_MASK);
> -		__flush_invalidate_dcache_page_alias(tmp, phys);
> -		tmp = TLBTEMP_BASE_1 + (addr & DCACHE_ALIAS_MASK);
> -		__flush_invalidate_dcache_page_alias(tmp, phys);
> -		__invalidate_icache_page_alias(tmp, phys);
> +		for (i = 0; i < nr; i++) {
> +			tmp = TLBTEMP_BASE_1 + (phys & DCACHE_ALIAS_MASK);
> +			__flush_invalidate_dcache_page_alias(tmp, phys);
> +			tmp = TLBTEMP_BASE_1 + (addr & DCACHE_ALIAS_MASK);
> +			__flush_invalidate_dcache_page_alias(tmp, phys);
> +			__invalidate_icache_page_alias(tmp, phys);
> +			phys += PAGE_SIZE;
> +		}
>  		preempt_enable();
>  
> -		clear_bit(PG_arch_1, &page->flags);
> +		clear_bit(PG_arch_1, &folio->flags);
>  	}
>  #else
> -	if (!PageReserved(page) && !test_bit(PG_arch_1, &page->flags)
> +	if (!folio_test_reserved(folio) && !test_bit(PG_arch_1, &folio->flags)
>  	    && (vma->vm_flags & VM_EXEC) != 0) {
> -		unsigned long paddr = (unsigned long)kmap_atomic(page);
> -		__flush_dcache_page(paddr);
> -		__invalidate_icache_page(paddr);
> -		set_bit(PG_arch_1, &page->flags);
> -		kunmap_atomic((void *)paddr);
> +		for (i = 0; i < nr; i++) {
> +			void *paddr = kmap_local_folio(folio, i * PAGE_SIZE);
> +			__flush_dcache_page((unsigned long)paddr);
> +			__invalidate_icache_page((unsigned long)paddr);
> +			kunmap_local(paddr);
> +		}
> +		set_bit(PG_arch_1, &folio->flags);
>  	}
>  #endif
>  }
> -- 
> 2.39.2
> 
> 

-- 
Sincerely yours,
Mike.