121 lines
3.0 KiB
C
121 lines
3.0 KiB
C
|
/*
|
||
|
|
* highmem.c: virtual kernel memory mappings for high memory
|
||
|
|
*
|
||
|
|
* Provides kernel-static versions of atomic kmap functions originally
|
||
|
|
* found as inlines in include/asm-sparc/highmem.h. These became
|
||
|
|
* needed as kmap_atomic() and kunmap_atomic() started getting
|
||
|
|
* called from within modules.
|
||
|
|
* -- Tomas Szepe <szepe@pinerecords.com>, September 2002
|
||
|
|
*
|
||
|
|
* But kmap_atomic() and kunmap_atomic() cannot be inlined in
|
||
|
|
* modules because they are loaded with btfixup-ped functions.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
|
||
|
|
* gives a more generic (and caching) interface. But kmap_atomic can
|
||
|
|
* be used in IRQ contexts, so in some (very limited) cases we need it.
|
||
|
|
*
|
||
|
|
* XXX This is an old text. Actually, it's good to use atomic kmaps,
|
||
|
|
* provided you remember that they are atomic and not try to sleep
|
||
|
|
* with a kmap taken, much like a spinlock. Non-atomic kmaps are
|
||
|
|
* shared by CPUs, and so precious, and establishing them requires IPI.
|
||
|
|
* Atomic kmaps are lightweight and we may have NCPUS more of them.
|
||
|
|
*/
|
||
|
|
#include <linux/mm.h>
|
||
|
|
#include <linux/highmem.h>
|
||
|
|
#include <asm/pgalloc.h>
|
||
|
|
#include <asm/cacheflush.h>
|
||
|
|
#include <asm/tlbflush.h>
|
||
|
|
#include <asm/fixmap.h>
|
||
|
|
|
||
|
|
void *kmap_atomic(struct page *page, enum km_type type)
|
||
|
|
{
|
||
|
|
unsigned long 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);
|
||
|
|
|
||
|
|
/* XXX Fix - Anton */
|
||
|
|
#if 0
|
||
|
|
__flush_cache_one(vaddr);
|
||
|
|
#else
|
||
|
|
flush_cache_all();
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#ifdef CONFIG_DEBUG_HIGHMEM
|
||
|
|
BUG_ON(!pte_none(*(kmap_pte-idx)));
|
||
|
|
#endif
|
||
|
|
set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
|
||
|
|
/* XXX Fix - Anton */
|
||
|
|
#if 0
|
||
|
|
__flush_tlb_one(vaddr);
|
||
|
|
#else
|
||
|
|
flush_tlb_all();
|
||
|
|
#endif
|
||
|
|
|
||
|
|
return (void*) vaddr;
|
||
|
|
}
|
||
|
|
|
||
|
|
void kunmap_atomic(void *kvaddr, enum km_type type)
|
||
|
|
{
|
||
|
|
#ifdef CONFIG_DEBUG_HIGHMEM
|
||
|
|
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
|
||
|
|
unsigned long idx = type + KM_TYPE_NR*smp_processor_id();
|
||
|
|
|
||
|
|
if (vaddr < FIXADDR_START) { // FIXME
|
||
|
|
dec_preempt_count();
|
||
|
|
preempt_check_resched();
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
|
||
|
|
|
||
|
|
/* XXX Fix - Anton */
|
||
|
|
#if 0
|
||
|
|
__flush_cache_one(vaddr);
|
||
|
|
#else
|
||
|
|
flush_cache_all();
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* 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);
|
||
|
|
/* XXX Fix - Anton */
|
||
|
|
#if 0
|
||
|
|
__flush_tlb_one(vaddr);
|
||
|
|
#else
|
||
|
|
flush_tlb_all();
|
||
|
|
#endif
|
||
|
|
#endif
|
||
|
|
|
||
|
|
dec_preempt_count();
|
||
|
|
preempt_check_resched();
|
||
|
|
}
|
||
|
|
|
||
|
|
/* We may be fed a pagetable here by ptep_to_xxx and others. */
|
||
|
|
struct page *kmap_atomic_to_page(void *ptr)
|
||
|
|
{
|
||
|
|
unsigned long idx, vaddr = (unsigned long)ptr;
|
||
|
|
pte_t *pte;
|
||
|
|
|
||
|
|
if (vaddr < SRMMU_NOCACHE_VADDR)
|
||
|
|
return virt_to_page(ptr);
|
||
|
|
if (vaddr < PKMAP_BASE)
|
||
|
|
return pfn_to_page(__nocache_pa(vaddr) >> PAGE_SHIFT);
|
||
|
|
BUG_ON(vaddr < FIXADDR_START);
|
||
|
|
BUG_ON(vaddr > FIXADDR_TOP);
|
||
|
|
|
||
|
|
idx = virt_to_fix(vaddr);
|
||
|
|
pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
|
||
|
|
return pte_page(*pte);
|
||
|
|
}
|