aboutsummaryrefslogblamecommitdiffstats
path: root/arch/x86/mm/highmem_32.c
blob: 6f31ee56c00849f14cd94454b9c5d2067388a74d (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
                          
                         
                                                







                                          
                    








                               
                      





                                                                               
                                                                          

                                                          
                                                        
 
                            
                      
 
                                                                             
                            
 


                                          
                                      
                                                   
                                                    
                                           
                                                  
                                   
 
                             
 

                                
                                    


                                                 
                           
 




                                                                    
 
                                                    
 
                                   
 
                                  
 
                                                                 




                                                     
                                         










                                                                             
                                                      
                                      
                                           
         
                           
              

                                                            
         
      
 
                           
 
                               
 











                                                      
                                   
 






















                                                                               
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/swap.h> /* for totalram_pages */

void *kmap(struct page *page)
{
	might_sleep();
	if (!PageHighMem(page))
		return page_address(page);
	return kmap_high(page);
}
EXPORT_SYMBOL(kmap);

void kunmap(struct page *page)
{
	if (in_interrupt())
		BUG();
	if (!PageHighMem(page))
		return;
	kunmap_high(page);
}
EXPORT_SYMBOL(kunmap);

/*
 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
 * no global lock is needed and because the kmap code must perform a global TLB
 * invalidation when the kmap pool wraps.
 *
 * However when holding an atomic kmap it is not legal to sleep, so atomic
 * kmaps are appropriate for short, tight code paths only.
 */
void *kmap_atomic_prot(struct page *page, pgprot_t prot)
{
	unsigned long vaddr;
	int idx, type;

	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
	pagefault_disable();

	if (!PageHighMem(page))
		return page_address(page);

	type = kmap_atomic_idx_push();
	idx = type + KM_TYPE_NR*smp_processor_id();
	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
	BUG_ON(!pte_none(*(kmap_pte-idx)));
	set_pte(kmap_pte-idx, mk_pte(page, prot));
	arch_flush_lazy_mmu_mode();

	return (void *)vaddr;
}
EXPORT_SYMBOL(kmap_atomic_prot);

void *kmap_atomic(struct page *page)
{
	return kmap_atomic_prot(page, kmap_prot);
}
EXPORT_SYMBOL(kmap_atomic);

/*
 * This is the same as kmap_atomic() but can map memory that doesn't
 * have a struct page associated with it.
 */
void *kmap_atomic_pfn(unsigned long pfn)
{
	return kmap_atomic_prot_pfn(pfn, kmap_prot);
}
EXPORT_SYMBOL_GPL(kmap_atomic_pfn);

void __kunmap_atomic(void *kvaddr)
{
	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;

	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
		int idx, type;

		type = kmap_atomic_idx();
		idx = type + KM_TYPE_NR * smp_processor_id();

#ifdef CONFIG_DEBUG_HIGHMEM
		WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
#endif
		/*
		 * Force other mappings to Oops if they'll try to access this
		 * pte without first remap it.  Keeping stale mappings around
		 * is a bad idea also, in case the page changes cacheability
		 * attributes or becomes a protected page in a hypervisor.
		 */
		kpte_clear_flush(kmap_pte-idx, vaddr);
		kmap_atomic_idx_pop();
		arch_flush_lazy_mmu_mode();
	}
#ifdef CONFIG_DEBUG_HIGHMEM
	else {
		BUG_ON(vaddr < PAGE_OFFSET);
		BUG_ON(vaddr >= (unsigned long)high_memory);
	}
#endif

	pagefault_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);

struct page *kmap_atomic_to_page(void *ptr)
{
	unsigned long idx, vaddr = (unsigned long)ptr;
	pte_t *pte;

	if (vaddr < FIXADDR_START)
		return virt_to_page(ptr);

	idx = virt_to_fix(vaddr);
	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
	return pte_page(*pte);
}
EXPORT_SYMBOL(kmap_atomic_to_page);

void __init set_highmem_pages_init(void)
{
	struct zone *zone;
	int nid;

	for_each_zone(zone) {
		unsigned long zone_start_pfn, zone_end_pfn;

		if (!is_highmem(zone))
			continue;

		zone_start_pfn = zone->zone_start_pfn;
		zone_end_pfn = zone_start_pfn + zone->spanned_pages;

		nid = zone_to_nid(zone);
		printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
				zone->name, nid, zone_start_pfn, zone_end_pfn);

		add_highpages_with_active_regions(nid, zone_start_pfn,
				 zone_end_pfn);
	}
	totalram_pages += totalhigh_pages;
}