Author: markj Date: Wed Feb 13 17:38:47 2019 New Revision: 344107 URL: https://svnweb.freebsd.org/changeset/base/344107
Log: Implement pmap_clear_modify() for RISC-V. Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D18875 Modified: head/sys/riscv/riscv/pmap.c Modified: head/sys/riscv/riscv/pmap.c ============================================================================== --- head/sys/riscv/riscv/pmap.c Wed Feb 13 17:19:37 2019 (r344106) +++ head/sys/riscv/riscv/pmap.c Wed Feb 13 17:38:47 2019 (r344107) @@ -4074,6 +4074,14 @@ pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t 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 * _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
