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[src/trunk]: src/sys/arch/hppa/hppa Convert pmap_check_alias into a function ...
details: https://anonhg.NetBSD.org/src/rev/c43fca1cdb9b
branches: trunk
changeset: 931757:c43fca1cdb9b
user: skrll <skrll%NetBSD.org@localhost>
date: Thu Apr 30 06:16:47 2020 +0000
description:
Convert pmap_check_alias into a function that resolves any aliases issues
to deal with the locking around entering a mapping of the same page with
and alias issue in the same pmap (pmap lock already held in pmap_enter)
This has the added benefit of only flushing the troublesome mappings.
The locking could be simplified further here and an PV list iterator
function with callback is probably useful.
diffstat:
sys/arch/hppa/hppa/pmap.c | 145 ++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 129 insertions(+), 16 deletions(-)
diffs (200 lines):
diff -r acd1c54f6752 -r c43fca1cdb9b sys/arch/hppa/hppa/pmap.c
--- a/sys/arch/hppa/hppa/pmap.c Thu Apr 30 04:26:29 2020 +0000
+++ b/sys/arch/hppa/hppa/pmap.c Thu Apr 30 06:16:47 2020 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.111 2020/04/16 09:51:56 skrll Exp $ */
+/* $NetBSD: pmap.c,v 1.112 2020/04/30 06:16:47 skrll Exp $ */
/*-
* Copyright (c) 2001, 2002, 2020 The NetBSD Foundation, Inc.
@@ -65,7 +65,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.111 2020/04/16 09:51:56 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.112 2020/04/30 06:16:47 skrll Exp $");
#include "opt_cputype.h"
@@ -184,7 +184,8 @@
static inline bool pmap_pv_locked(const struct vm_page_md *md);
static inline void pmap_flush_page(struct vm_page *, bool);
-static int pmap_check_alias(struct vm_page *, vaddr_t, pt_entry_t);
+static void pmap_resolve_alias(struct vm_page *, struct pmap *, vaddr_t,
+ pt_entry_t);
static void pmap_syncicache_page(struct vm_page *, pmap_t, vaddr_t);
static void pmap_page_physload(paddr_t, paddr_t);
@@ -537,17 +538,126 @@
}
#endif
-static int
-pmap_check_alias(struct vm_page *pg, vaddr_t va, pt_entry_t pte)
+static void
+pmap_resolve_alias(struct vm_page *pg, struct pmap *pm, vaddr_t va,
+ pt_entry_t pte)
{
- struct vm_page_md * const md = VM_PAGE_TO_MD(pg);
- struct pv_entry *pve;
- int ret = 0;
UVMHIST_FUNC(__func__);
- UVMHIST_CALLARGS(maphist, "pg %#jx va %#jx pte %#jx", (uintptr_t)pg,
- va, pte, 0);
+ UVMHIST_CALLARGS(maphist, "pg %#jx pm %#jx va %#jx pte %#jx",
+ (uintptr_t)pg, (uintptr_t)pm, va, pte);
+
+ struct vm_page_md * const md = VM_PAGE_TO_MD(pg);
+ struct pv_entry *pve, *npve, **pvp;
+
+ restart:
+ pmap_pv_lock(md);
+ pvp = &md->pvh_list;
+ for (pve = md->pvh_list; pve; pve = npve) {
+ const pmap_t ppm = pve->pv_pmap;
+ const vaddr_t pva = pve->pv_va & PV_VAMASK;
+
+ UVMHIST_LOG(maphist, "... pm %#jx va %#jx", (uintptr_t)ppm,
+ pva, 0, 0);
+
+ npve = pve->pv_next;
+
+ volatile pt_entry_t *pde;
+ pt_entry_t ppte;
+ if (pve->pv_va & PV_KENTER) {
+ /* Get the pte for this mapping */
+ pde = pmap_pde_get(ppm->pm_pdir, pva);
+ ppte = pmap_pte_get(pde, pva);
+ } else {
+ /*
+ * We have to seamlessly get a hold on the pmap's lock
+ * while holding the PV head lock, to know that the
+ * mapping is still in place and we can operate on it.
+ * If that can't be had, drop the PV head lock, wait
+ * for the pmap's lock to become available, and then
+ * try again.
+ */
+ UVMHIST_LOG(maphist, "... pm %#jx va %#jx... checking",
+ (uintptr_t)ppm, pva, 0, 0);
+
+ bool locked = true;
+ if (pm != ppm) {
+ pmap_reference(ppm);
+ locked = pmap_trylock(ppm);
+ }
+
+ if (!locked) {
+ pmap_pv_unlock(md);
+ pmap_lock(ppm);
+ /* nothing */
+ pmap_unlock(ppm);
+ pmap_destroy(ppm);
+
+ UVMHIST_LOG(maphist, "... failed lock", 0, 0, 0,
+ 0);
+ goto restart;
+ }
+ pde = pmap_pde_get(ppm->pm_pdir, pva);
+ ppte = pmap_pte_get(pde, pva);
+ md->pvh_attrs |= pmap_pvh_attrs(ppte);
+ }
+
+ const bool writeable =
+ ((pte | ppte) & PTE_PROT(TLB_WRITE)) != 0;
+
+ if ((va & HPPA_PGAOFF) != (pva & HPPA_PGAOFF) && writeable) {
+ UVMHIST_LOG(maphist,
+ "aliased writeable mapping %#jx:%#jx",
+ ppm->pm_space, pva, 0, 0);
+
+ pmap_pte_flush(ppm, pva, ppte);
+ if (ppte & PTE_PROT(TLB_WIRED))
+ ppm->pm_stats.wired_count--;
+ ppm->pm_stats.resident_count--;
+
+ if (pve->pv_va & PV_KENTER) {
+ /*
+ * This is an unmanaged mapping, it must be
+ * preserved. Move it back on the list and
+ * advance the end-of-list pointer.
+ */
+ *pvp = pve;
+ pvp = &pve->pv_next;
+ } else {
+ pmap_pte_set(pde, pva, 0);
+
+ /* Remove pve from list */
+ *pvp = npve;
+
+ pmap_pv_unlock(md);
+ pmap_pv_free(pve);
+ if (pm != ppm) {
+ pmap_unlock(ppm);
+ pmap_destroy(ppm);
+
+ }
+ UVMHIST_LOG(maphist, "... removed", 0,
+ 0, 0, 0);
+ goto restart;
+ }
+ } else {
+ UVMHIST_LOG(maphist, "not aliased writeable mapping",
+ 0,0,0,0);
+
+ if (!(pve->pv_va & PV_KENTER) && pm != ppm) {
+ pmap_unlock(ppm);
+ pmap_destroy(ppm);
+ }
+ *pvp = pve;
+ pvp = &pve->pv_next;
+ }
+ }
+ md->pvh_attrs &= ~PVF_EXEC;
+ *pvp = NULL;
+
+#ifdef DEBUG
+ int ret = 0;
/* check for non-equ aliased mappings */
for (pve = md->pvh_list; pve; pve = pve->pv_next) {
vaddr_t pva = pve->pv_va & PV_VAMASK;
@@ -565,10 +675,14 @@
ret++;
}
}
+ UVMHIST_LOG(maphist, "check returned %jd", ret, 0, 0, 0);
+#endif
- UVMHIST_LOG(maphist, "<--- done (%jd)", ret, 0, 0, 0);
+ pmap_pv_unlock(md);
- return (ret);
+ UVMHIST_LOG(maphist, "<--- done", 0, 0, 0, 0);
+
+ return;
}
/*
@@ -1319,8 +1433,8 @@
panic("%s: no pv entries available", __func__);
}
pte |= PTE_PROT(pmap_prot(pmap, prot));
- if (pmap_check_alias(pg, va, pte))
- pmap_page_remove(pg);
+ pmap_resolve_alias(pg, pmap, va, pte);
+
pmap_pv_lock(md);
pmap_pv_enter(pg, pve, pmap, va, ptp, 0);
pmap_pv_unlock(md);
@@ -1893,8 +2007,7 @@
UVMHIST_LOG(maphist, "va %#jx pa %#jx pte %#jx TLB_KENTER",
va, pa, pte, 0);
- if (pmap_check_alias(pg, va, pte))
- pmap_page_remove(pg);
+ pmap_resolve_alias(pg, pmap_kernel(), va, pte);
pmap_pv_lock(md);
pmap_pv_enter(pg, pve, pmap_kernel(), va, NULL, PV_KENTER);
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