From 93845d4535bc00748a722fc8fdb079fa630bdbd9 Mon Sep 17 00:00:00 2001 From: Mark Kettenis Date: Fri, 11 Sep 2015 22:02:19 +0000 Subject: Make the powerpc pmap (more) mpsafe by protecting both the pmap itself and the pv lists with a mutex. This should make pmap_enter(9), pmap_remove(9) and pmap_page_protect(9) safe to use without holding the kernel lock. ok visa@, mpi@, deraadt@ --- sys/arch/powerpc/include/pmap.h | 6 ++++- sys/arch/powerpc/powerpc/pmap.c | 59 +++++++++++++++++++++++++++++++++++++---- 2 files changed, 59 insertions(+), 6 deletions(-) (limited to 'sys/arch/powerpc') diff --git a/sys/arch/powerpc/include/pmap.h b/sys/arch/powerpc/include/pmap.h index 2b55338e569..de3607db813 100644 --- a/sys/arch/powerpc/include/pmap.h +++ b/sys/arch/powerpc/include/pmap.h @@ -1,4 +1,4 @@ -/* $OpenBSD: pmap.h,v 1.57 2015/06/05 11:38:19 mpi Exp $ */ +/* $OpenBSD: pmap.h,v 1.58 2015/09/11 22:02:18 kettenis Exp $ */ /* $NetBSD: pmap.h,v 1.1 1996/09/30 16:34:29 ws Exp $ */ /*- @@ -163,11 +163,15 @@ int reserve_dumppages(caddr_t p); #endif /* _KERNEL */ +#include + struct vm_page_md { + struct mutex pv_mtx; LIST_HEAD(,pte_desc) pv_list; }; #define VM_MDPAGE_INIT(pg) do { \ + mtx_init(&(pg)->mdpage.pv_mtx, IPL_VM); \ LIST_INIT(&((pg)->mdpage.pv_list)); \ } while (0) diff --git a/sys/arch/powerpc/powerpc/pmap.c b/sys/arch/powerpc/powerpc/pmap.c index 093f32b780e..d867415084f 100644 --- a/sys/arch/powerpc/powerpc/pmap.c +++ b/sys/arch/powerpc/powerpc/pmap.c @@ -1,4 +1,4 @@ -/* $OpenBSD: pmap.c,v 1.161 2015/09/08 21:28:36 kettenis Exp $ */ +/* $OpenBSD: pmap.c,v 1.162 2015/09/11 22:02:18 kettenis Exp $ */ /* * Copyright (c) 2015 Martin Pieuchot @@ -489,15 +489,26 @@ pmap_enter_pv(struct pte_desc *pted, struct vm_page *pg) return; } + mtx_enter(&pg->mdpage.pv_mtx); LIST_INSERT_HEAD(&(pg->mdpage.pv_list), pted, pted_pv_list); pted->pted_va |= PTED_VA_MANAGED_M; + mtx_leave(&pg->mdpage.pv_mtx); } void pmap_remove_pv(struct pte_desc *pted) { + struct vm_page *pg; + + if (ppc_proc_is_64b) + pg = PHYS_TO_VM_PAGE(pted->p.pted_pte64.pte_lo & PTE_RPGN_64); + else + pg = PHYS_TO_VM_PAGE(pted->p.pted_pte32.pte_lo & PTE_RPGN_32); + + mtx_enter(&pg->mdpage.pv_mtx); pted->pted_va &= ~PTED_VA_MANAGED_M; LIST_REMOVE(pted, pted_pv_list); + mtx_leave(&pg->mdpage.pv_mtx); } @@ -642,7 +653,6 @@ pmap_remove(pmap_t pm, vaddr_t sva, vaddr_t eva) struct pte_desc *pted; vaddr_t va; - KERNEL_LOCK(); PMAP_VP_LOCK(pm); for (va = sva; va < eva; va += PAGE_SIZE) { pted = pmap_vp_lookup(pm, va); @@ -650,7 +660,6 @@ pmap_remove(pmap_t pm, vaddr_t sva, vaddr_t eva) pmap_remove_pted(pm, pted); } PMAP_VP_UNLOCK(pm); - KERNEL_UNLOCK(); } /* @@ -963,6 +972,7 @@ pmap_test_attrs(struct vm_page *pg, u_int flagbit) if ((bits == flagbit)) return bits; + mtx_enter(&pg->mdpage.pv_mtx); LIST_FOREACH(pted, &(pg->mdpage.pv_list), pted_pv_list) { void *pte; @@ -981,11 +991,13 @@ pmap_test_attrs(struct vm_page *pg, u_int flagbit) if (bits == flagbit) break; } + mtx_leave(&pg->mdpage.pv_mtx); atomic_setbits_int(&pg->pg_flags, bits); return bits; } + int pmap_clear_attrs(struct vm_page *pg, u_int flagbit) { @@ -999,6 +1011,7 @@ pmap_clear_attrs(struct vm_page *pg, u_int flagbit) bits = pg->pg_flags & flagbit; + mtx_enter(&pg->mdpage.pv_mtx); LIST_FOREACH(pted, &(pg->mdpage.pv_list), pted_pv_list) { void *pte; @@ -1030,6 +1043,7 @@ pmap_clear_attrs(struct vm_page *pg, u_int flagbit) } PMAP_HASH_UNLOCK(s); } + mtx_leave(&pg->mdpage.pv_mtx); /* * this is done a second time, because while walking the list @@ -1148,7 +1162,7 @@ again: void pmap_reference(pmap_t pm) { - pm->pm_refs++; + atomic_inc_int(&pm->pm_refs); } /* @@ -1160,7 +1174,7 @@ pmap_destroy(pmap_t pm) { int refs; - refs = --pm->pm_refs; + refs = atomic_dec_int_nv(&pm->pm_refs); if (refs == -1) panic("re-entering pmap_destroy"); if (refs > 0) @@ -2030,19 +2044,54 @@ pmap_page_protect(struct vm_page *pg, vm_prot_t prot) pmap_t pm; if (prot == PROT_NONE) { + mtx_enter(&pg->mdpage.pv_mtx); while ((pted = LIST_FIRST(&(pg->mdpage.pv_list))) != NULL) { + pmap_reference(pted->pted_pmap); pm = pted->pted_pmap; + mtx_leave(&pg->mdpage.pv_mtx); + PMAP_VP_LOCK(pm); + + /* + * We dropped the pvlist lock before grabbing + * the pmap lock to avoid lock ordering + * problems. This means we have to check the + * pvlist again since somebody else might have + * modified it. All we care about is that the + * pvlist entry matches the pmap we just + * locked. If it doesn't, unlock the pmap and + * try again. + */ + mtx_enter(&pg->mdpage.pv_mtx); + if ((pted = LIST_FIRST(&(pg->mdpage.pv_list))) == NULL || + pted->pted_pmap != pm) { + mtx_leave(&pg->mdpage.pv_mtx); + PMAP_VP_UNLOCK(pm); + pmap_destroy(pm); + mtx_enter(&pg->mdpage.pv_mtx); + continue; + } + + pted->pted_va &= ~PTED_VA_MANAGED_M; + LIST_REMOVE(pted, pted_pv_list); + mtx_leave(&pg->mdpage.pv_mtx); + pmap_remove_pted(pm, pted); + PMAP_VP_UNLOCK(pm); + pmap_destroy(pm); + mtx_enter(&pg->mdpage.pv_mtx); } + mtx_leave(&pg->mdpage.pv_mtx); /* page is being reclaimed, sync icache next use */ atomic_clearbits_int(&pg->pg_flags, PG_PMAP_EXE); return; } + mtx_enter(&pg->mdpage.pv_mtx); LIST_FOREACH(pted, &(pg->mdpage.pv_list), pted_pv_list) pmap_pted_ro(pted, prot); + mtx_leave(&pg->mdpage.pv_mtx); } void -- cgit v1.2.3