selftests/rseq: Implement rseq numa node id field selftest

Test the NUMA node id extension rseq field. Compare it against the value
returned by the getcpu(2) system call while pinned on a specific core.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-7-mathieu.desnoyers@efficios.com

diff --git a/tools/testing/selftests/rseq/basic_test.c b/tools/testing/selftests/rseq/basic_test.c
index d8efbfb8919337a78003b11ce25e9b9d1106e811..295eea16466fe81761db0d3f52aea06d8ef5982d 100644 (file)
--- a/tools/testing/selftests/rseq/basic_test.c
+++ b/tools/testing/selftests/rseq/basic_test.c
@@ -22,6 +22,8 @@ void test_cpu_pointer(void)
        CPU_ZERO(&test_affinity);
        for (i = 0; i < CPU_SETSIZE; i++) {
                if (CPU_ISSET(i, &affinity)) {
+                       int node;
+
                        CPU_SET(i, &test_affinity);
                        sched_setaffinity(0, sizeof(test_affinity),
                                        &test_affinity);
@@ -29,6 +31,8 @@ void test_cpu_pointer(void)
                        assert(rseq_current_cpu() == i);
                        assert(rseq_current_cpu_raw() == i);
                        assert(rseq_cpu_start() == i);
+                       node = rseq_fallback_current_node();
+                       assert(rseq_current_node_id() == node);
                        CPU_CLR(i, &test_affinity);
                }
        }

diff --git a/tools/testing/selftests/rseq/rseq-abi.h b/tools/testing/selftests/rseq/rseq-abi.h
index 00ac846d85b0bb982b9202fe31b14c1401ee7b53..a1faa9162d5212e8c748798cee8e41dbefcc35d8 100644 (file)
--- a/tools/testing/selftests/rseq/rseq-abi.h
+++ b/tools/testing/selftests/rseq/rseq-abi.h
@@ -147,6 +147,14 @@ struct rseq_abi {
         */
        __u32 flags;
 
+       /*
+        * Restartable sequences node_id 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 NUMA node ID.
+        */
+       __u32 node_id;
+
        /*
         * Flexible array member at end of structure, after last feature field.
         */

diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c
index 1e8e3265bdbf8d561ebe1058276f1381e9fa0f76..4e4aa006004c8b7ad7c193981db864de25b27e65 100644 (file)
--- a/tools/testing/selftests/rseq/rseq.c
+++ b/tools/testing/selftests/rseq/rseq.c
@@ -79,6 +79,11 @@ static int sys_rseq(struct rseq_abi *rseq_abi, uint32_t rseq_len,
        return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig);
 }
 
+static int sys_getcpu(unsigned *cpu, unsigned *node)
+{
+       return syscall(__NR_getcpu, cpu, node, NULL);
+}
+
 int rseq_available(void)
 {
        int rc;
@@ -201,3 +206,16 @@ int32_t rseq_fallback_current_cpu(void)
        }
        return cpu;
 }
+
+int32_t rseq_fallback_current_node(void)
+{
+       uint32_t cpu_id, node_id;
+       int ret;
+
+       ret = sys_getcpu(&cpu_id, &node_id);
+       if (ret) {
+               perror("sys_getcpu()");
+               return ret;
+       }
+       return (int32_t) node_id;
+}

diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h
index 95adc1e1b0db689e33538b36bbdc339ba889c735..fd17d0e54a1b2c831c591c8fe14b532915e30568 100644 (file)
--- a/tools/testing/selftests/rseq/rseq.h
+++ b/tools/testing/selftests/rseq/rseq.h
@@ -20,6 +20,15 @@
 #include "rseq-abi.h"
 #include "compiler.h"
 
+#ifndef rseq_sizeof_field
+#define rseq_sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
+#endif
+
+#ifndef rseq_offsetofend
+#define rseq_offsetofend(TYPE, MEMBER) \
+       (offsetof(TYPE, MEMBER) + rseq_sizeof_field(TYPE, MEMBER))
+#endif
+
 /*
  * Empty code injection macros, override when testing.
  * It is important to consider that the ASM injection macros need to be
@@ -128,6 +137,11 @@ int rseq_unregister_current_thread(void);
  */
 int32_t rseq_fallback_current_cpu(void);
 
+/*
+ * Restartable sequence fallback for reading the current node number.
+ */
+int32_t rseq_fallback_current_node(void);
+
 /*
  * Values returned can be either the current CPU number, -1 (rseq is
  * uninitialized), or -2 (rseq initialization has failed).
@@ -163,6 +177,20 @@ static inline uint32_t rseq_current_cpu(void)
        return cpu;
 }
 
+static inline bool rseq_node_id_available(void)
+{
+       return (int) rseq_feature_size >= rseq_offsetofend(struct rseq_abi, node_id);
+}
+
+/*
+ * Current NUMA node number.
+ */
+static inline uint32_t rseq_current_node_id(void)
+{
+       assert(rseq_node_id_available());
+       return RSEQ_ACCESS_ONCE(rseq_get_abi()->node_id);
+}
+
 static inline void rseq_clear_rseq_cs(void)
 {
        RSEQ_WRITE_ONCE(rseq_get_abi()->rseq_cs.arch.ptr, 0);