diff options
Diffstat (limited to 'sys/arch/arm64')
| -rw-r--r-- | sys/arch/arm64/arm64/pmap.c | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/sys/arch/arm64/arm64/pmap.c b/sys/arch/arm64/arm64/pmap.c index af2294bead1..df734710e98 100644 --- a/sys/arch/arm64/arm64/pmap.c +++ b/sys/arch/arm64/arm64/pmap.c @@ -1,4 +1,4 @@ -/* $OpenBSD: pmap.c,v 1.55 2018/08/15 20:18:31 kettenis Exp $ */ +/* $OpenBSD: pmap.c,v 1.56 2018/08/16 15:36:04 patrick Exp $ */ /* * Copyright (c) 2008-2009,2014-2016 Dale Rahn <drahn@dalerahn.com> * @@ -2174,20 +2174,27 @@ uint32_t pmap_asid[NUM_ASID / 32]; void pmap_allocate_asid(pmap_t pm) { + uint32_t bits; int asid, bit; - do { - asid = arc4random() & (NUM_ASID - 2); - bit = (asid & (32 - 1)); - } while (asid == 0 || (pmap_asid[asid / 32] & (3U << bit))); + for (;;) { + do { + asid = arc4random() & (NUM_ASID - 2); + bit = (asid & (32 - 1)); + bits = pmap_asid[asid / 32]; + } while (asid == 0 || (bits & (3U << bit))); - atomic_setbits_int(&pmap_asid[asid / 32], 3U << bit); + if (atomic_cas_uint(&pmap_asid[asid / 32], bits, + bits | (3U << bit)) == bits) + break; + } pm->pm_asid = asid; } void pmap_free_asid(pmap_t pm) { + uint32_t bits; int bit; KASSERT(pm != curcpu()->ci_curpm); @@ -2195,7 +2202,12 @@ pmap_free_asid(pmap_t pm) cpu_tlb_flush_asid_all((uint64_t)(pm->pm_asid | ASID_USER) << 48); bit = (pm->pm_asid & (32 - 1)); - atomic_clearbits_int(&pmap_asid[pm->pm_asid / 32], 3U << bit); + for (;;) { + bits = pmap_asid[pm->pm_asid / 32]; + if (atomic_cas_uint(&pmap_asid[pm->pm_asid / 32], bits, + bits & ~(3U << bit)) == bits) + break; + } } void |