mempool: Introduce COW_ZERO poison value

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Id7fdfa0ceb8631e1b4bfe594d9e68c4d8663c6ef

diff --git a/src/rseq-mempool.c b/src/rseq-mempool.c
index 4508ff4c404d4dcde46b9849e7e7f332bbe67210..15dd4e52e3b3fd4bcf90c33415daa4da9b104ceb 100644 (file)
--- a/src/rseq-mempool.c
+++ b/src/rseq-mempool.c
@@ -56,11 +56,13 @@
 #define RANGE_HEADER_OFFSET    sizeof(struct rseq_mempool_range)
 
 #if RSEQ_BITS_PER_LONG == 64
-# define DEFAULT_PRIVATE_POISON_VALUE  0x5555555555555555ULL
+# define DEFAULT_COW_INIT_POISON_VALUE 0x5555555555555555ULL
 #else
-# define DEFAULT_PRIVATE_POISON_VALUE  0x55555555UL
+# define DEFAULT_COW_INIT_POISON_VALUE 0x55555555UL
 #endif
 
+#define DEFAULT_COW_ZERO_POISON_VALUE  0x0
+
 struct free_list_node;
 
 struct free_list_node {
@@ -952,7 +954,10 @@ struct rseq_mempool *rseq_mempool_create(const char *pool_name,
                attr.stride = RSEQ_MEMPOOL_STRIDE;      /* Use default */
        if (attr.robust_set && !attr.poison_set) {
                attr.poison_set = true;
-               attr.poison = DEFAULT_PRIVATE_POISON_VALUE;
+               if (attr.populate_policy != RSEQ_MEMPOOL_POPULATE_PRIVATE_ALL)
+                       attr.poison = DEFAULT_COW_INIT_POISON_VALUE;
+               else
+                       attr.poison = DEFAULT_COW_ZERO_POISON_VALUE;
        }
        if (item_len > attr.stride || attr.stride < (size_t) rseq_get_page_len() ||
                        !is_pow2(attr.stride)) {