diff options
| author | Mark Kettenis <kettenis@cvs.openbsd.org> | 2021-09-14 16:14:51 +0000 |
|---|---|---|
| committer | Mark Kettenis <kettenis@cvs.openbsd.org> | 2021-09-14 16:14:51 +0000 |
| commit | 8424a88248eed2f5dee42c941ed8cf29287fbab6 (patch) | |
| tree | b771e29899a3d70b5c69d9817862216dab452039 | |
| parent | 09f0bb0a15040539fad2b07927b9fddd2b686d82 (diff) | |
Make pmap_extract() mpsafe by grabbing the kernel lock for userland pmaps
while walking the page tables.
ok mpi@, deraadt@
| -rw-r--r-- | sys/arch/amd64/amd64/pmap.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/sys/arch/amd64/amd64/pmap.c b/sys/arch/amd64/amd64/pmap.c index d74061e45a5..4773d35121d 100644 --- a/sys/arch/amd64/amd64/pmap.c +++ b/sys/arch/amd64/amd64/pmap.c @@ -1,4 +1,4 @@ -/* $OpenBSD: pmap.c,v 1.147 2021/09/06 12:59:59 mpi Exp $ */ +/* $OpenBSD: pmap.c,v 1.148 2021/09/14 16:14:50 kettenis Exp $ */ /* $NetBSD: pmap.c,v 1.3 2003/05/08 18:13:13 thorpej Exp $ */ /* @@ -1504,7 +1504,7 @@ pmap_pdes_valid(vaddr_t va, pd_entry_t *lastpde) int pmap_extract(struct pmap *pmap, vaddr_t va, paddr_t *pap) { - pt_entry_t *ptes; + pt_entry_t *ptes, pte; int level, offs; if (pmap == pmap_kernel() && va >= PMAP_DIRECT_BASE && @@ -1513,16 +1513,23 @@ pmap_extract(struct pmap *pmap, vaddr_t va, paddr_t *pap) return 1; } + if (pmap != pmap_kernel()) + mtx_enter(&pmap->pm_mtx); + level = pmap_find_pte_direct(pmap, va, &ptes, &offs); + pte = ptes[offs]; - if (__predict_true(level == 0 && pmap_valid_entry(ptes[offs]))) { + if (pmap != pmap_kernel()) + mtx_leave(&pmap->pm_mtx); + + if (__predict_true(level == 0 && pmap_valid_entry(pte))) { if (pap != NULL) - *pap = (ptes[offs] & PG_FRAME) | (va & PAGE_MASK); + *pap = (pte & PG_FRAME) | (va & PAGE_MASK); return 1; } - if (level == 1 && (ptes[offs] & (PG_PS|PG_V)) == (PG_PS|PG_V)) { + if (level == 1 && (pte & (PG_PS|PG_V)) == (PG_PS|PG_V)) { if (pap != NULL) - *pap = (ptes[offs] & PG_LGFRAME) | (va & PAGE_MASK_L2); + *pap = (pte & PG_LGFRAME) | (va & PAGE_MASK_L2); return 1; } |