Document alignment of rseq_abi for allocated size

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ie78f475a2d6f8756b166db45d96367104871c2a8

diff --git a/src/rseq.c b/src/rseq.c
index e904b443e1212fc63b95da1ada172e50db241612..4f01aad97c74566b86298125e430ac3c9d700016 100644 (file)
--- a/src/rseq.c
+++ b/src/rseq.c
@@ -70,6 +70,12 @@ static int rseq_reg_success; /* At least one rseq registration has succeded. */
 /* Original struct rseq allocation size is 32 bytes. */
 #define ORIG_RSEQ_ALLOC_SIZE           32
 
+/*
+ * The alignment on RSEQ_THREAD_AREA_ALLOC_SIZE guarantees that the
+ * rseq_abi structure allocated size is at least
+ * RSEQ_THREAD_AREA_ALLOC_SIZE bytes to hold extra space for yet unknown
+ * kernel rseq extensions.
+ */
 static
 __thread struct rseq_abi __rseq_abi __attribute__((tls_model("initial-exec"), aligned(RSEQ_THREAD_AREA_ALLOC_SIZE))) = {
        .cpu_id = RSEQ_ABI_CPU_ID_UNINITIALIZED,