Since with the current design there's one device per domain, and one

domain per pagetable, there's no need for a backpointer to the domain
in the pagetable entry descriptor.  There can't be any other domain.
Also since there's no list, no list entry member is needed either.

This reduces early allocation to half of the previous size.  I think
it's possible to reduce it even further and not need a pagetable entry
descriptor at all, but I need to think about that a bit more.

diff --git a/sys/arch/arm64/dev/smmu.c b/sys/arch/arm64/dev/smmu.c
index a04f27c..0afe765 100644 (file)
--- a/sys/arch/arm64/dev/smmu.c
+++ b/sys/arch/arm64/dev/smmu.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: smmu.c,v 1.8 2021/03/06 19:25:27 patrick Exp $ */
+/* $OpenBSD: smmu.c,v 1.9 2021/03/06 19:30:07 patrick Exp $ */
 /*
  * Copyright (c) 2008-2009,2014-2016 Dale Rahn <drahn@dalerahn.com>
  * Copyright (c) 2021 Patrick Wildt <patrick@blueri.se>
@@ -64,9 +64,7 @@ CTASSERT(sizeof(struct smmuvp0) == sizeof(struct smmuvp2));
 CTASSERT(sizeof(struct smmuvp0) == sizeof(struct smmuvp3));
 
 struct pte_desc {
-       LIST_ENTRY(pte_desc) pted_pv_list;
        uint64_t pted_pte;
-       struct smmu_domain *pted_dom;
        vaddr_t pted_va;
 };
 
@@ -96,9 +94,9 @@ int smmu_vp_enter(struct smmu_domain *, vaddr_t, struct pte_desc *, int);
 
 void smmu_fill_pte(struct smmu_domain *, vaddr_t, paddr_t, struct pte_desc *,
     vm_prot_t, int, int);
-void smmu_pte_update(struct pte_desc *, uint64_t *);
-void smmu_pte_insert(struct pte_desc *);
-void smmu_pte_remove(struct pte_desc *, int);
+void smmu_pte_update(struct smmu_domain *, struct pte_desc *, uint64_t *);
+void smmu_pte_insert(struct smmu_domain *, struct pte_desc *);
+void smmu_pte_remove(struct smmu_domain *, struct pte_desc *, int);
 
 int smmu_enter(struct smmu_domain *, vaddr_t, paddr_t, vm_prot_t, int, int);
 void smmu_map(struct smmu_domain *, vaddr_t, paddr_t, vm_prot_t, int, int);
@@ -1014,7 +1012,6 @@ smmu_fill_pte(struct smmu_domain *dom, vaddr_t va, paddr_t pa,
     struct pte_desc *pted, vm_prot_t prot, int flags, int cache)
 {
        pted->pted_va = va;
-       pted->pted_dom = dom;
 
        switch (cache) {
        case PMAP_CACHE_WB:
@@ -1039,9 +1036,8 @@ smmu_fill_pte(struct smmu_domain *dom, vaddr_t va, paddr_t pa,
 }
 
 void
-smmu_pte_update(struct pte_desc *pted, uint64_t *pl3)
+smmu_pte_update(struct smmu_domain *dom, struct pte_desc *pted, uint64_t *pl3)
 {
-       struct smmu_domain *dom = pted->pted_dom;
        uint64_t pte, access_bits;
        uint64_t attr = 0;
 
@@ -1107,9 +1103,8 @@ smmu_pte_update(struct pte_desc *pted, uint64_t *pl3)
 }
 
 void
-smmu_pte_insert(struct pte_desc *pted)
+smmu_pte_insert(struct smmu_domain *dom, struct pte_desc *pted)
 {
-       struct smmu_domain *dom = pted->pted_dom;
        uint64_t *pl3;
 
        if (smmu_vp_lookup(dom, pted->pted_va, &pl3) == NULL) {
@@ -1117,19 +1112,18 @@ smmu_pte_insert(struct pte_desc *pted)
                    " for %lx va domain %p", __func__, pted->pted_va, dom);
        }
 
-       smmu_pte_update(pted, pl3);
+       smmu_pte_update(dom, pted, pl3);
        membar_producer(); /* XXX bus dma sync? */
 }
 
 void
-smmu_pte_remove(struct pte_desc *pted, int remove_pted)
+smmu_pte_remove(struct smmu_domain *dom, struct pte_desc *pted, int remove_pted)
 {
        /* put entry into table */
        /* need to deal with ref/change here */
        struct smmuvp1 *vp1;
        struct smmuvp2 *vp2;
        struct smmuvp3 *vp3;
-       struct smmu_domain *dom = pted->pted_dom;
 
        if (dom->sd_4level)
                vp1 = dom->sd_vp.l0->vp[VP_IDX0(pted->pted_va)];
@@ -1201,7 +1195,7 @@ smmu_map(struct smmu_domain *dom, vaddr_t va, paddr_t pa, vm_prot_t prot,
        smmu_fill_pte(dom, va, pa, pted, prot, flags, cache);
 
        /* Insert updated information */
-       smmu_pte_insert(pted);
+       smmu_pte_insert(dom, pted);
 }
 
 void
@@ -1217,7 +1211,7 @@ smmu_unmap(struct smmu_domain *dom, vaddr_t va)
        KASSERT(pted != NULL);
 
        /* Remove mapping from pagetable, keep it alive */
-       smmu_pte_remove(pted, 0);
+       smmu_pte_remove(dom, pted, 0);
        membar_producer(); /* XXX bus dma sync? */
 
        /* Invalidate IOTLB */
@@ -1242,7 +1236,7 @@ smmu_remove(struct smmu_domain *dom, vaddr_t va)
        KASSERT(pted != NULL);
 
        /* Mapping already removed, remove pted as well */
-       smmu_pte_remove(pted, 1);
+       smmu_pte_remove(dom, pted, 1);
 
        /* Destroy pted */
        pted->pted_pte = 0;