diff options
Diffstat (limited to 'malloc/arena.c')
| -rw-r--r-- | malloc/arena.c | 59 |
1 files changed, 56 insertions, 3 deletions
diff --git a/malloc/arena.c b/malloc/arena.c index 3c9c0ec..f7e9158 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -274,17 +274,52 @@ next_env_entry (char ***position) #endif -#ifdef SHARED +#if defined(SHARED) || defined(USE_MTAG) static void * __failing_morecore (ptrdiff_t d) { return (void *) MORECORE_FAILURE; } +#endif +#ifdef SHARED extern struct dl_open_hook *_dl_open_hook; libc_hidden_proto (_dl_open_hook); #endif +#ifdef USE_MTAG + +/* Generate a new (random) tag value for PTR and tag the memory it + points to upto the end of the usable size for the chunk containing + it. Return the newly tagged pointer. */ +static void * +__mtag_tag_new_usable (void *ptr) +{ + if (ptr) + { + mchunkptr cp = mem2chunk(ptr); + /* This likely will never happen, but we can't handle retagging + chunks from the dumped main arena. So just return the + existing pointer. */ + if (DUMPED_MAIN_ARENA_CHUNK (cp)) + return ptr; + ptr = __libc_mtag_tag_region (__libc_mtag_new_tag (ptr), + CHUNK_AVAILABLE_SIZE (cp) - CHUNK_HDR_SZ); + } + return ptr; +} + +/* Generate a new (random) tag value for PTR, set the tags for the + memory to the new tag and initialize the memory contents to VAL. + In practice this function will only be called with VAL=0, but we + keep this parameter to maintain the same prototype as memset. */ +static void * +__mtag_tag_new_memset (void *ptr, int val, size_t size) +{ + return __libc_mtag_memset_with_tag (__libc_mtag_new_tag (ptr), val, size); +} +#endif + static void ptmalloc_init (void) { @@ -293,6 +328,24 @@ ptmalloc_init (void) __malloc_initialized = 0; +#ifdef USE_MTAG + if ((TUNABLE_GET_FULL (glibc, mem, tagging, int32_t, NULL) & 1) != 0) + { + /* If the tunable says that we should be using tagged memory + and that morecore does not support tagged regions, then + disable it. */ + if (__MTAG_SBRK_UNTAGGED) + __morecore = __failing_morecore; + + __mtag_mmap_flags = __MTAG_MMAP_FLAGS; + __tag_new_memset = __mtag_tag_new_memset; + __tag_region = __libc_mtag_tag_region; + __tag_new_usable = __mtag_tag_new_usable; + __tag_at = __libc_mtag_address_get_tag; + __mtag_granule_mask = ~(size_t)(__MTAG_GRANULE_SIZE - 1); + } +#endif + #ifdef SHARED /* In case this libc copy is in a non-default namespace, never use brk. Likewise if dlopened from statically linked program. The @@ -509,7 +562,7 @@ new_heap (size_t size, size_t top_pad) } } } - if (__mprotect (p2, size, PROT_READ | PROT_WRITE) != 0) + if (__mprotect (p2, size, MTAG_MMAP_FLAGS | PROT_READ | PROT_WRITE) != 0) { __munmap (p2, HEAP_MAX_SIZE); return 0; @@ -539,7 +592,7 @@ grow_heap (heap_info *h, long diff) { if (__mprotect ((char *) h + h->mprotect_size, (unsigned long) new_size - h->mprotect_size, - PROT_READ | PROT_WRITE) != 0) + MTAG_MMAP_FLAGS | PROT_READ | PROT_WRITE) != 0) return -2; h->mprotect_size = new_size; |