selftests/rseq: Implement rseq mm_cid field support

Add support for the mm_cid field (per-memory-map concurrency ID) of
struct rseq to rseq selftests.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-11-mathieu.desnoyers@efficios.com

diff --git a/tools/testing/selftests/rseq/rseq-abi.h b/tools/testing/selftests/rseq/rseq-abi.h
index a1faa9162d5212e8c748798cee8e41dbefcc35d8..fb4ec8a75dd48bb4813a3232e4403b8cc5337ef6 100644 (file)
--- a/tools/testing/selftests/rseq/rseq-abi.h
+++ b/tools/testing/selftests/rseq/rseq-abi.h
@@ -155,6 +155,15 @@ struct rseq_abi {
         */
        __u32 node_id;
 
+       /*
+        * Restartable sequences mm_cid field. Updated by the kernel. Read by
+        * user-space with single-copy atomicity semantics. This field should
+        * only be read by the thread which registered this data structure.
+        * Aligned on 32-bit. Contains the current thread's concurrency ID
+        * (allocated uniquely within a memory map).
+        */
+       __u32 mm_cid;
+
        /*
         * Flexible array member at end of structure, after last feature field.
         */

diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h
index fd17d0e54a1b2c831c591c8fe14b532915e30568..10ebf13644fac6f6bc25f8beaf98df634ddbabf3 100644 (file)
--- a/tools/testing/selftests/rseq/rseq.h
+++ b/tools/testing/selftests/rseq/rseq.h
@@ -191,6 +191,16 @@ static inline uint32_t rseq_current_node_id(void)
        return RSEQ_ACCESS_ONCE(rseq_get_abi()->node_id);
 }
 
+static inline bool rseq_mm_cid_available(void)
+{
+       return (int) rseq_feature_size >= rseq_offsetofend(struct rseq_abi, mm_cid);
+}
+
+static inline uint32_t rseq_current_mm_cid(void)
+{
+       return RSEQ_ACCESS_ONCE(rseq_get_abi()->mm_cid);
+}
+
 static inline void rseq_clear_rseq_cs(void)
 {
        RSEQ_WRITE_ONCE(rseq_get_abi()->rseq_cs.arch.ptr, 0);