104 lines
2.3 KiB
C
104 lines
2.3 KiB
C
#include <linux/config.h>
|
|
#include <linux/module.h>
|
|
#include <linux/highmem.h>
|
|
#include <asm/tlbflush.h>
|
|
|
|
void *__kmap(struct page *page)
|
|
{
|
|
void *addr;
|
|
|
|
might_sleep();
|
|
if (!PageHighMem(page))
|
|
return page_address(page);
|
|
addr = kmap_high(page);
|
|
flush_tlb_one((unsigned long)addr);
|
|
|
|
return addr;
|
|
}
|
|
|
|
void __kunmap(struct page *page)
|
|
{
|
|
if (in_interrupt())
|
|
BUG();
|
|
if (!PageHighMem(page))
|
|
return;
|
|
kunmap_high(page);
|
|
}
|
|
|
|
/*
|
|
* 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 is is not legal to sleep, so atomic
|
|
* kmaps are appropriate for short, tight code paths only.
|
|
*/
|
|
|
|
void *__kmap_atomic(struct page *page, enum km_type type)
|
|
{
|
|
enum fixed_addresses idx;
|
|
unsigned long vaddr;
|
|
|
|
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
|
|
inc_preempt_count();
|
|
if (!PageHighMem(page))
|
|
return page_address(page);
|
|
|
|
idx = type + KM_TYPE_NR*smp_processor_id();
|
|
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
|
|
#ifdef CONFIG_DEBUG_HIGHMEM
|
|
if (!pte_none(*(kmap_pte-idx)))
|
|
BUG();
|
|
#endif
|
|
set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
|
|
local_flush_tlb_one((unsigned long)vaddr);
|
|
|
|
return (void*) vaddr;
|
|
}
|
|
|
|
void __kunmap_atomic(void *kvaddr, enum km_type type)
|
|
{
|
|
#ifdef CONFIG_DEBUG_HIGHMEM
|
|
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
|
|
enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
|
|
|
|
if (vaddr < FIXADDR_START) { // FIXME
|
|
dec_preempt_count();
|
|
preempt_check_resched();
|
|
return;
|
|
}
|
|
|
|
if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx))
|
|
BUG();
|
|
|
|
/*
|
|
* force other mappings to Oops if they'll try to access
|
|
* this pte without first remap it
|
|
*/
|
|
pte_clear(&init_mm, vaddr, kmap_pte-idx);
|
|
local_flush_tlb_one(vaddr);
|
|
#endif
|
|
|
|
dec_preempt_count();
|
|
preempt_check_resched();
|
|
}
|
|
|
|
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);
|
|
EXPORT_SYMBOL(__kunmap);
|
|
EXPORT_SYMBOL(__kmap_atomic);
|
|
EXPORT_SYMBOL(__kunmap_atomic);
|
|
EXPORT_SYMBOL(__kmap_atomic_to_page);
|