diff --git a/src/pages.c b/src/pages.c index 7ef3de75..88a9d630 100644 --- a/src/pages.c +++ b/src/pages.c @@ -180,6 +180,31 @@ pages_map(void *addr, size_t size, size_t alignment, bool *commit) { assert(alignment >= PAGE); assert(ALIGNMENT_ADDR2BASE(addr, alignment) == addr); +#if defined(__FreeBSD__) && defined(MAP_EXCL) + /* + * FreeBSD has mechanisms both to mmap at specific address without + * touching existing mappings, and to mmap with specific alignment. + */ + { + int prot = *commit ? PAGES_PROT_COMMIT : PAGES_PROT_DECOMMIT; + int flags = mmap_flags; + + if (addr != NULL) { + flags |= MAP_FIXED | MAP_EXCL; + } else { + unsigned alignment_bits = ffs_zu(alignment); + assert(alignment_bits > 1); + flags |= MAP_ALIGNED(alignment_bits - 1); + } + + void *ret = mmap(addr, size, prot, flags, -1, 0); + if (ret == MAP_FAILED) { + ret = NULL; + } + + return ret; + } +#endif /* * Ideally, there would be a way to specify alignment to mmap() (like * NetBSD has), but in the absence of such a feature, we have to work