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Implement pmap_clear_modify() for RISC-V.

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Reviewed by:	kib
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D18875
This commit is contained in:
Mark Johnston 2019-02-13 17:38:47 +00:00
parent f6893f09d5
commit 91c85dd88b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=344107
1 changed files with 80 additions and 2 deletions
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82
sys/riscv/riscv/pmap.c
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@ -4074,6 +4074,14 @@ pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, int advice)
void
pmap_clear_modify(vm_page_t m)
{
struct md_page *pvh;
struct rwlock *lock;
pmap_t pmap;
pv_entry_t next_pv, pv;
pd_entry_t *l2, oldl2;
pt_entry_t *l3, oldl3;
vm_offset_t va;
int md_gen, pvh_gen;
KASSERT((m->oflags & VPO_UNMANAGED) == 0,
("pmap_clear_modify: page %p is not managed", m));
@ -4088,8 +4096,78 @@ pmap_clear_modify(vm_page_t m)
*/
if ((m->aflags & PGA_WRITEABLE) == 0)
return;
/* RISCVTODO: We lack support for tracking if a page is modified */
pvh = (m->flags & PG_FICTITIOUS) != 0 ? &pv_dummy :
pa_to_pvh(VM_PAGE_TO_PHYS(m));
lock = VM_PAGE_TO_PV_LIST_LOCK(m);
rw_rlock(&pvh_global_lock);
rw_wlock(lock);
restart:
TAILQ_FOREACH_SAFE(pv, &pvh->pv_list, pv_next, next_pv) {
pmap = PV_PMAP(pv);
if (!PMAP_TRYLOCK(pmap)) {
pvh_gen = pvh->pv_gen;
rw_wunlock(lock);
PMAP_LOCK(pmap);
rw_wlock(lock);
if (pvh_gen != pvh->pv_gen) {
PMAP_UNLOCK(pmap);
goto restart;
}
}
va = pv->pv_va;
l2 = pmap_l2(pmap, va);
oldl2 = pmap_load(l2);
if ((oldl2 & PTE_W) != 0) {
if (pmap_demote_l2_locked(pmap, l2, va, &lock)) {
if ((oldl2 & PTE_SW_WIRED) == 0) {
/*
* Write protect the mapping to a
* single page so that a subsequent
* write access may repromote.
*/
va += VM_PAGE_TO_PHYS(m) -
PTE_TO_PHYS(oldl2);
l3 = pmap_l2_to_l3(l2, va);
oldl3 = pmap_load(l3);
if ((oldl3 & PTE_V) != 0) {
while (!atomic_fcmpset_long(l3,
&oldl3, oldl3 & ~(PTE_D |
PTE_W)))
cpu_spinwait();
vm_page_dirty(m);
pmap_invalidate_page(pmap, va);
}
}
}
}
PMAP_UNLOCK(pmap);
}
TAILQ_FOREACH(pv, &m->md.pv_list, pv_next) {
pmap = PV_PMAP(pv);
if (!PMAP_TRYLOCK(pmap)) {
md_gen = m->md.pv_gen;
pvh_gen = pvh->pv_gen;
rw_wunlock(lock);
PMAP_LOCK(pmap);
rw_wlock(lock);
if (pvh_gen != pvh->pv_gen || md_gen != m->md.pv_gen) {
PMAP_UNLOCK(pmap);
goto restart;
}
}
l2 = pmap_l2(pmap, pv->pv_va);
KASSERT((pmap_load(l2) & PTE_RWX) == 0,
("pmap_clear_modify: found a 2mpage in page %p's pv list",
m));
l3 = pmap_l2_to_l3(l2, pv->pv_va);
if ((pmap_load(l3) & (PTE_D | PTE_W)) == (PTE_D | PTE_W)) {
pmap_clear_bits(l3, PTE_D);
pmap_invalidate_page(pmap, pv->pv_va);
}
PMAP_UNLOCK(pmap);
}
rw_wunlock(lock);
rw_runlock(&pvh_global_lock);
}
void *