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| author | nwhitehorn <nwhitehorn@FreeBSD.org> | 2015-11-24 16:10:21 +0000 |
|---|---|---|
| committer | nwhitehorn <nwhitehorn@FreeBSD.org> | 2015-11-24 16:10:21 +0000 |
| commit | 745b5bcad49247c234953ff587296084cefbe3c8 (patch) | |
| tree | f880587797adef3e067f78d6b92b381d9fbaa5f4 /sys/powerpc/aim | |
| parent | a02e9843fe7e2547efa40d2e07f1f38d6932c847 (diff) | |
| download | FreeBSD-src-745b5bcad49247c234953ff587296084cefbe3c8.zip FreeBSD-src-745b5bcad49247c234953ff587296084cefbe3c8.tar.gz | |
Use what we really mean (powerpc_lwsync()) rather than the Linux-compat
mb() here and provide some more documentation on what, exactly, makes this
code safe.
Requested by and discussed with: kib, alc
Diffstat (limited to 'sys/powerpc/aim')
| -rw-r--r-- | sys/powerpc/aim/slb.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/sys/powerpc/aim/slb.c b/sys/powerpc/aim/slb.c index 89cfabf..aa6a214 100644 --- a/sys/powerpc/aim/slb.c +++ b/sys/powerpc/aim/slb.c @@ -140,7 +140,7 @@ make_new_leaf(uint64_t esid, uint64_t slbv, struct slbtnode *parent) * that a lockless searcher always sees a valid path through * the tree. */ - mb(); + powerpc_lwsync(); idx = esid2idx(esid, parent->ua_level); parent->u.ua_child[idx] = child; @@ -188,7 +188,7 @@ make_intermediate(uint64_t esid, struct slbtnode *parent) idx = esid2idx(child->ua_base, inter->ua_level); inter->u.ua_child[idx] = child; setbit(&inter->ua_alloc, idx); - mb(); + powerpc_lwsync(); /* Set up parent to point to intermediate node ... */ idx = esid2idx(inter->ua_base, parent->ua_level); @@ -241,6 +241,12 @@ user_va_to_slb_entry(pmap_t pm, vm_offset_t va) return ((ua->u.slb_entries[idx].slbe & SLBE_VALID) ? &ua->u.slb_entries[idx] : NULL); + /* + * The following accesses are implicitly ordered under the POWER + * ISA by load dependencies (the store ordering is provided by + * the powerpc_lwsync() calls elsewhere) and so are run without + * barriers. + */ ua = ua->u.ua_child[idx]; if (ua == NULL || esid2base(esid, ua->ua_level) != ua->ua_base) |
