selftests/rseq: Implement basic percpu ops mm_cid test

Adapt to the rseq.h API changes introduced by commits
"selftests/rseq: <arch>: Template memory ordering and percpu access mode".

Build a new basic_percpu_ops_mm_cid_test to test the new "mm_cid" rseq
field.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221122203932.231377-19-mathieu.desnoyers@efficios.com

tools/testing/selftests/rseq/.gitignore

 # SPDX-License-Identifier: GPL-2.0-only
 basic_percpu_ops_test
+basic_percpu_ops_mm_cid_test
 basic_test
 basic_rseq_op_test
 param_test

tools/testing/selftests/rseq/Makefile

@@ -12,7 +12,7 @@ LDLIBS += -lpthread -ldl
 # still track changes to header files and depend on shared object.
 OVERRIDE_TARGETS = 1
 
-TEST_GEN_PROGS = basic_test basic_percpu_ops_test param_test \
+TEST_GEN_PROGS = basic_test basic_percpu_ops_test basic_percpu_ops_mm_cid_test param_test \
 		param_test_benchmark param_test_compare_twice
 
 TEST_GEN_PROGS_EXTENDED = librseq.so
@@ -29,6 +29,9 @@ $(OUTPUT)/librseq.so: rseq.c rseq.h rseq-*.h
 $(OUTPUT)/%: %.c $(TEST_GEN_PROGS_EXTENDED) rseq.h rseq-*.h
 	$(CC) $(CFLAGS) $< $(LDLIBS) -lrseq -o $@
 
+$(OUTPUT)/basic_percpu_ops_mm_cid_test: basic_percpu_ops_test.c $(TEST_GEN_PROGS_EXTENDED) rseq.h rseq-*.h
+	$(CC) $(CFLAGS) -DBUILDOPT_RSEQ_PERCPU_MM_CID_ID $< $(LDLIBS) -lrseq -o $@
+
 $(OUTPUT)/param_test_benchmark: param_test.c $(TEST_GEN_PROGS_EXTENDED) \
 					rseq.h rseq-*.h
 	$(CC) $(CFLAGS) -DBENCHMARK $< $(LDLIBS) -lrseq -o $@

tools/testing/selftests/rseq/basic_percpu_ops_test.c

@@ -12,6 +12,32 @@
 #include "../kselftest.h"
 #include "rseq.h"
 
+#ifdef BUILDOPT_RSEQ_PERCPU_MM_CID
+# define RSEQ_PERCPU	RSEQ_PERCPU_MM_CID
+static
+int get_current_cpu_id(void)
+{
+	return rseq_current_mm_cid();
+}
+static
+bool rseq_validate_cpu_id(void)
+{
+	return rseq_mm_cid_available();
+}
+#else
+# define RSEQ_PERCPU	RSEQ_PERCPU_CPU_ID
+static
+int get_current_cpu_id(void)
+{
+	return rseq_cpu_start();
+}
+static
+bool rseq_validate_cpu_id(void)
+{
+	return rseq_current_cpu_raw() >= 0;
+}
+#endif
+
 struct percpu_lock_entry {
 	intptr_t v;
 } __attribute__((aligned(128)));
@@ -51,9 +77,9 @@ int rseq_this_cpu_lock(struct percpu_lock *lock)
 	for (;;) {
 		int ret;
 
-		cpu = rseq_cpu_start();
-		ret = rseq_cmpeqv_storev(&lock->c[cpu].v,
-					 0, 1, cpu);
+		cpu = get_current_cpu_id();
+		ret = rseq_cmpeqv_storev(RSEQ_MO_RELAXED, RSEQ_PERCPU,
+					 &lock->c[cpu].v, 0, 1, cpu);
 		if (rseq_likely(!ret))
 			break;
 		/* Retry if comparison fails or rseq aborts. */
@@ -141,13 +167,14 @@ void this_cpu_list_push(struct percpu_list *list,
 		intptr_t *targetptr, newval, expect;
 		int ret;
 
-		cpu = rseq_cpu_start();
+		cpu = get_current_cpu_id();
 		/* Load list->c[cpu].head with single-copy atomicity. */
 		expect = (intptr_t)RSEQ_READ_ONCE(list->c[cpu].head);
 		newval = (intptr_t)node;
 		targetptr = (intptr_t *)&list->c[cpu].head;
 		node->next = (struct percpu_list_node *)expect;
-		ret = rseq_cmpeqv_storev(targetptr, expect, newval, cpu);
+		ret = rseq_cmpeqv_storev(RSEQ_MO_RELAXED, RSEQ_PERCPU,
+					 targetptr, expect, newval, cpu);
 		if (rseq_likely(!ret))
 			break;
 		/* Retry if comparison fails or rseq aborts. */
@@ -170,12 +197,13 @@ struct percpu_list_node *this_cpu_list_pop(struct percpu_list *list,
 		long offset;
 		int ret, cpu;
 
-		cpu = rseq_cpu_start();
+		cpu = get_current_cpu_id();
 		targetptr = (intptr_t *)&list->c[cpu].head;
 		expectnot = (intptr_t)NULL;
 		offset = offsetof(struct percpu_list_node, next);
 		load = (intptr_t *)&head;
-		ret = rseq_cmpnev_storeoffp_load(targetptr, expectnot,
+		ret = rseq_cmpnev_storeoffp_load(RSEQ_MO_RELAXED, RSEQ_PERCPU,
+						 targetptr, expectnot,
 						 offset, load, cpu);
 		if (rseq_likely(!ret)) {
 			if (_cpu)
@@ -295,6 +323,10 @@ int main(int argc, char **argv)
 			errno, strerror(errno));
 		goto error;
 	}
+	if (!rseq_validate_cpu_id()) {
+		fprintf(stderr, "Error: cpu id getter unavailable\n");
+		goto error;
+	}
 	printf("spinlock\n");
 	test_percpu_spinlock();
 	printf("percpu_list\n");