arch/sh/mm/cache.c

Source file repositories/reference/linux-study-clean/arch/sh/mm/cache.c

File Facts

System
Linux kernel
Corpus path
arch/sh/mm/cache.c
Extension
.c
Size
9550 bytes
Lines
355
Domain
Architecture Layer
Bucket
arch/sh
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

test_bit(PG_dcache_clean, &folio->flags.f)) {
		void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
		memcpy(vto, src, len);
		kunmap_coherent(vto);
	} else {
		memcpy(dst, src, len);
		if (boot_cpu_data.dcache.n_aliases)
			clear_bit(PG_dcache_clean, &folio->flags.f);
	}

	if (vma->vm_flags & VM_EXEC)
		flush_cache_page(vma, vaddr, page_to_pfn(page));
}

void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
			 unsigned long vaddr, void *dst, const void *src,
			 unsigned long len)
{
	struct folio *folio = page_folio(page);

	if (boot_cpu_data.dcache.n_aliases && folio_mapped(folio) &&
	    test_bit(PG_dcache_clean, &folio->flags.f)) {
		void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
		memcpy(dst, vfrom, len);
		kunmap_coherent(vfrom);
	} else {
		memcpy(dst, src, len);
		if (boot_cpu_data.dcache.n_aliases)
			clear_bit(PG_dcache_clean, &folio->flags.f);
	}
}

void copy_user_highpage(struct page *to, struct page *from,
			unsigned long vaddr, struct vm_area_struct *vma)
{
	struct folio *src = page_folio(from);
	void *vfrom, *vto;

	vto = kmap_atomic(to);

	if (boot_cpu_data.dcache.n_aliases && folio_mapped(src) &&
	    test_bit(PG_dcache_clean, &src->flags.f)) {
		vfrom = kmap_coherent(from, vaddr);
		copy_page(vto, vfrom);
		kunmap_coherent(vfrom);
	} else {
		vfrom = kmap_atomic(from);
		copy_page(vto, vfrom);
		kunmap_atomic(vfrom);
	}

	if (pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK) ||
	    (vma->vm_flags & VM_EXEC))
		__flush_purge_region(vto, PAGE_SIZE);

	kunmap_atomic(vto);
	/* Make sure this page is cleared on other CPU's too before using it */
	smp_wmb();
}
EXPORT_SYMBOL(copy_user_highpage);

void clear_user_highpage(struct page *page, unsigned long vaddr)
{
	void *kaddr = kmap_atomic(page);

	clear_page(kaddr);

	if (pages_do_alias((unsigned long)kaddr, vaddr & PAGE_MASK))
		__flush_purge_region(kaddr, PAGE_SIZE);

	kunmap_atomic(kaddr);
}
EXPORT_SYMBOL(clear_user_highpage);

void __update_cache(struct vm_area_struct *vma,
		    unsigned long address, pte_t pte)
{
	unsigned long pfn = pte_pfn(pte);

	if (!boot_cpu_data.dcache.n_aliases)
		return;

	if (pfn_valid(pfn)) {
		struct folio *folio = page_folio(pfn_to_page(pfn));
		int dirty = !test_and_set_bit(PG_dcache_clean, &folio->flags.f);
		if (dirty)
			__flush_purge_region(folio_address(folio),
						folio_size(folio));
	}
}

Annotation

Implementation Notes