/*
* Invalidate a pte in a pmap and synchronize with target cpus
* as required. Throw away the modified and access bits. Use
* pmap_clean_pte() to do the same thing but also get an interlocked
* modified/access status.
*
* Clearing the field first (basically clearing VPTE_V) prevents any
* new races from occuring while we invalidate the TLB (i.e. the pmap
* on the real cpu), then clear it again to clean out any race that
* might have occured before the invalidation completed.
*/
void
pmap_inval_pte(volatile vpte_t *ptep, struct pmap *pmap, vm_offset_t va)
{
*ptep = 0;
pmap_inval_cpu(pmap, va, PAGE_SIZE);
*ptep = 0;
}
/*
* Invalidating page directory entries requires some additional
* sophistication. The cachemask must be cleared so the kernel
* resynchronizes its temporary page table mappings cache.
*/
void
pmap_inval_pde(volatile vpte_t *ptep, struct pmap *pmap, vm_offset_t va)
{
*ptep = 0;
pmap_inval_cpu(pmap, va, SEG_SIZE);
*ptep = 0;
pmap->pm_cpucachemask = 0;
}
/*
* This is an odd case and I'm not sure whether it even occurs in normal
* operation. Turn off write access to the page, clean out the tlb
* (the real cpu's pmap), and deal with any VPTE_M race that may have
* occured. VPTE_M is not cleared.
*/
vpte_t
pmap_setro_pte(volatile vpte_t *ptep, struct pmap *pmap, vm_offset_t va)
{
vpte_t pte;
pte = *ptep;
if (pte & VPTE_V) {
pte = *ptep;
atomic_clear_long(ptep, VPTE_RW);
pmap_inval_cpu(pmap, va, PAGE_SIZE);
pte |= *ptep & VPTE_M;
}
return(pte);
}
vpte_t
pmap_clean_pde(volatile vpte_t *ptep, struct pmap *pmap, vm_offset_t va)
{
vpte_t pte;
pte = *ptep;
if (pte & VPTE_V) {
atomic_clear_long(ptep, VPTE_W);
pmap_inval_cpu(pmap, va, SEG_SIZE);
pte = *ptep;
atomic_clear_long(ptep, VPTE_W|VPTE_M);
}
return(pte);
}
/*
* This is a combination of pmap_inval_pte() and pmap_clean_pte().
* Firts prevent races with the 'A' and 'M' bits, then clean out
* the tlb (the real cpu's pmap), then incorporate any races that
* may have occured in the mean time, and finally zero out the pte.
*/
vpte_t
pmap_inval_loadandclear(volatile vpte_t *ptep, struct pmap *pmap,
vm_offset_t va)
{
vpte_t pte;
pte = *ptep;
if (pte & VPTE_V) {
pte = *ptep;
atomic_clear_long(ptep, VPTE_RW);
pmap_inval_cpu(pmap, va, PAGE_SIZE);
pte |= *ptep & (VPTE_A | VPTE_M);
}
*ptep = 0;
return(pte);
}
