selftests/bpf: Add selftests for load-acquire and store-release instructions

Add the following ./test_progs tests:

  * atomics/load_acquire
  * atomics/store_release
  * arena_atomics/load_acquire
  * arena_atomics/store_release

They depend on the pre-defined __BPF_FEATURE_LOAD_ACQ_STORE_REL feature
macro, which implies -mcpu>=v4.

  $ ALLOWLIST=atomics/load_acquire,atomics/store_release,
  $ ALLOWLIST+=arena_atomics/load_acquire,arena_atomics/store_release

  $ ./test_progs-cpuv4 -a $ALLOWLIST

  #3/9     arena_atomics/load_acquire:OK
  #3/10    arena_atomics/store_release:OK
...
  #10/8    atomics/load_acquire:OK
  #10/9    atomics/store_release:OK

  $ ./test_progs -v -a $ALLOWLIST

  test_load_acquire:SKIP:Clang does not support BPF load-acquire or addr_space_cast
  #3/9     arena_atomics/load_acquire:SKIP
  test_store_release:SKIP:Clang does not support BPF store-release or addr_space_cast
  #3/10    arena_atomics/store_release:SKIP
...
  test_load_acquire:SKIP:Clang does not support BPF load-acquire
  #10/8    atomics/load_acquire:SKIP
  test_store_release:SKIP:Clang does not support BPF store-release
  #10/9    atomics/store_release:SKIP

Additionally, add several ./test_verifier tests:

  #65/u atomic BPF_LOAD_ACQ access through non-pointer  OK
  #65/p atomic BPF_LOAD_ACQ access through non-pointer  OK
  #66/u atomic BPF_STORE_REL access through non-pointer  OK
  #66/p atomic BPF_STORE_REL access through non-pointer  OK

  #67/u BPF_ATOMIC load-acquire, 8-bit OK
  #67/p BPF_ATOMIC load-acquire, 8-bit OK
  #68/u BPF_ATOMIC load-acquire, 16-bit OK
  #68/p BPF_ATOMIC load-acquire, 16-bit OK
  #69/u BPF_ATOMIC load-acquire, 32-bit OK
  #69/p BPF_ATOMIC load-acquire, 32-bit OK
  #70/u BPF_ATOMIC load-acquire, 64-bit OK
  #70/p BPF_ATOMIC load-acquire, 64-bit OK
  #71/u Cannot load-acquire from uninitialized src_reg OK
  #71/p Cannot load-acquire from uninitialized src_reg OK

  #76/u BPF_ATOMIC store-release, 8-bit OK
  #76/p BPF_ATOMIC store-release, 8-bit OK
  #77/u BPF_ATOMIC store-release, 16-bit OK
  #77/p BPF_ATOMIC store-release, 16-bit OK
  #78/u BPF_ATOMIC store-release, 32-bit OK
  #78/p BPF_ATOMIC store-release, 32-bit OK
  #79/u BPF_ATOMIC store-release, 64-bit OK
  #79/p BPF_ATOMIC store-release, 64-bit OK
  #80/u Cannot store-release from uninitialized src_reg OK
  #80/p Cannot store-release from uninitialized src_reg OK

Reviewed-by: Josh Don <[email protected]>
Signed-off-by: Peilin Ye <[email protected]>

Author: peilin-ye

include/linux/filter.h

@@ -364,6 +364,8 @@ static inline bool insn_is_cast_user(const struct bpf_insn *insn)
  *   BPF_XOR | BPF_FETCH      src_reg = atomic_fetch_xor(dst_reg + off16, src_reg);
  *   BPF_XCHG                 src_reg = atomic_xchg(dst_reg + off16, src_reg)
  *   BPF_CMPXCHG              r0 = atomic_cmpxchg(dst_reg + off16, r0, src_reg)
+ *   BPF_LOAD_ACQ             dst_reg = smp_load_acquire(src_reg + off16)
+ *   BPF_STORE_REL            smp_store_release(dst_reg + off16, src_reg)
  */
 
 #define BPF_ATOMIC_OP(SIZE, OP, DST, SRC, OFF)			\

tools/testing/selftests/bpf/prog_tests/arena_atomics.c

@@ -162,6 +162,60 @@ static void test_uaf(struct arena_atomics *skel)
 	ASSERT_EQ(skel->arena->uaf_recovery_fails, 0, "uaf_recovery_fails");
 }
 
+static void test_load_acquire(struct arena_atomics *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	if (skel->data->skip_lacq_srel_tests) {
+		printf("%s:SKIP:Clang does not support BPF load-acquire or addr_space_cast\n",
+		       __func__);
+		test__skip();
+		return;
+	}
+
+	/* No need to attach it, just run it directly */
+	prog_fd = bpf_program__fd(skel->progs.load_acquire);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->arena->load_acquire8_result, 0x12, "load_acquire8_result");
+	ASSERT_EQ(skel->arena->load_acquire16_result, 0x1234, "load_acquire16_result");
+	ASSERT_EQ(skel->arena->load_acquire32_result, 0x12345678, "load_acquire32_result");
+	ASSERT_EQ(skel->arena->load_acquire64_result, 0x1234567890abcdef,
+		  "load_acquire64_result");
+}
+
+static void test_store_release(struct arena_atomics *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	if (skel->data->skip_lacq_srel_tests) {
+		printf("%s:SKIP:Clang does not support BPF store-release or addr_space_cast\n",
+		       __func__);
+		test__skip();
+		return;
+	}
+
+	/* No need to attach it, just run it directly */
+	prog_fd = bpf_program__fd(skel->progs.store_release);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->arena->store_release8_result, 0x12, "store_release8_result");
+	ASSERT_EQ(skel->arena->store_release16_result, 0x1234, "store_release16_result");
+	ASSERT_EQ(skel->arena->store_release32_result, 0x12345678, "store_release32_result");
+	ASSERT_EQ(skel->arena->store_release64_result, 0x1234567890abcdef,
+		  "store_release64_result");
+}
+
 void test_arena_atomics(void)
 {
 	struct arena_atomics *skel;
@@ -171,7 +225,7 @@ void test_arena_atomics(void)
 	if (!ASSERT_OK_PTR(skel, "arena atomics skeleton open"))
 		return;
 
-	if (skel->data->skip_tests) {
+	if (skel->data->skip_all_tests) {
 		printf("%s:SKIP:no ENABLE_ATOMICS_TESTS or no addr_space_cast support in clang",
 		       __func__);
 		test__skip();
@@ -199,6 +253,11 @@ void test_arena_atomics(void)
 	if (test__start_subtest("uaf"))
 		test_uaf(skel);
 
+	if (test__start_subtest("load_acquire"))
+		test_load_acquire(skel);
+	if (test__start_subtest("store_release"))
+		test_store_release(skel);
+
 cleanup:
 	arena_atomics__destroy(skel);
 }

tools/testing/selftests/bpf/prog_tests/atomics.c

@@ -162,6 +162,56 @@ static void test_xchg(struct atomics_lskel *skel)
 	ASSERT_EQ(skel->bss->xchg32_result, 1, "xchg32_result");
 }
 
+static void test_load_acquire(struct atomics_lskel *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	if (skel->data->skip_lacq_srel_tests) {
+		printf("%s:SKIP:Clang does not support BPF load-acquire\n", __func__);
+		test__skip();
+		return;
+	}
+
+	/* No need to attach it, just run it directly */
+	prog_fd = skel->progs.load_acquire.prog_fd;
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->bss->load_acquire8_result, 0x12, "load_acquire8_result");
+	ASSERT_EQ(skel->bss->load_acquire16_result, 0x1234, "load_acquire16_result");
+	ASSERT_EQ(skel->bss->load_acquire32_result, 0x12345678, "load_acquire32_result");
+	ASSERT_EQ(skel->bss->load_acquire64_result, 0x1234567890abcdef, "load_acquire64_result");
+}
+
+static void test_store_release(struct atomics_lskel *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	if (skel->data->skip_lacq_srel_tests) {
+		printf("%s:SKIP:Clang does not support BPF store-release\n", __func__);
+		test__skip();
+		return;
+	}
+
+	/* No need to attach it, just run it directly */
+	prog_fd = skel->progs.store_release.prog_fd;
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->bss->store_release8_result, 0x12, "store_release8_result");
+	ASSERT_EQ(skel->bss->store_release16_result, 0x1234, "store_release16_result");
+	ASSERT_EQ(skel->bss->store_release32_result, 0x12345678, "store_release32_result");
+	ASSERT_EQ(skel->bss->store_release64_result, 0x1234567890abcdef, "store_release64_result");
+}
+
 void test_atomics(void)
 {
 	struct atomics_lskel *skel;
@@ -170,7 +220,7 @@ void test_atomics(void)
 	if (!ASSERT_OK_PTR(skel, "atomics skeleton load"))
 		return;
 
-	if (skel->data->skip_tests) {
+	if (skel->data->skip_all_tests) {
 		printf("%s:SKIP:no ENABLE_ATOMICS_TESTS (missing Clang BPF atomics support)",
 		       __func__);
 		test__skip();
@@ -193,6 +243,11 @@ void test_atomics(void)
 	if (test__start_subtest("xchg"))
 		test_xchg(skel);
 
+	if (test__start_subtest("load_acquire"))
+		test_load_acquire(skel);
+	if (test__start_subtest("store_release"))
+		test_store_release(skel);
+
 cleanup:
 	atomics_lskel__destroy(skel);
 }

tools/testing/selftests/bpf/progs/arena_atomics.c

@@ -19,9 +19,15 @@ struct {
 } arena SEC(".maps");
 
 #if defined(ENABLE_ATOMICS_TESTS) && defined(__BPF_FEATURE_ADDR_SPACE_CAST)
-bool skip_tests __attribute((__section__(".data"))) = false;
+bool skip_all_tests __attribute((__section__(".data"))) = false;
 #else
-bool skip_tests = true;
+bool skip_all_tests = true;
+#endif
+
+#if defined(__BPF_FEATURE_LOAD_ACQ_STORE_REL) && defined(__BPF_FEATURE_ADDR_SPACE_CAST)
+bool skip_lacq_srel_tests __attribute((__section__(".data"))) = false;
+#else
+bool skip_lacq_srel_tests = true;
 #endif
 
 __u32 pid = 0;
@@ -274,4 +280,56 @@ int uaf(const void *ctx)
 	return 0;
 }
 
+__u8 __arena_global load_acquire8_value = 0x12;
+__u16 __arena_global load_acquire16_value = 0x1234;
+__u32 __arena_global load_acquire32_value = 0x12345678;
+__u64 __arena_global load_acquire64_value = 0x1234567890abcdef;
+
+__u8 __arena_global load_acquire8_result = 0;
+__u16 __arena_global load_acquire16_result = 0;
+__u32 __arena_global load_acquire32_result = 0;
+__u64 __arena_global load_acquire64_result = 0;
+
+SEC("raw_tp/sys_enter")
+int load_acquire(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+
+#ifdef __BPF_FEATURE_LOAD_ACQ_STORE_REL
+	load_acquire8_result = __atomic_load_n(&load_acquire8_value, __ATOMIC_ACQUIRE);
+	load_acquire16_result = __atomic_load_n(&load_acquire16_value, __ATOMIC_ACQUIRE);
+	load_acquire32_result = __atomic_load_n(&load_acquire32_value, __ATOMIC_ACQUIRE);
+	load_acquire64_result = __atomic_load_n(&load_acquire64_value, __ATOMIC_ACQUIRE);
+#endif
+
+	return 0;
+}
+
+__u8 __arena_global store_release8_result = 0;
+__u16 __arena_global store_release16_result = 0;
+__u32 __arena_global store_release32_result = 0;
+__u64 __arena_global store_release64_result = 0;
+
+SEC("raw_tp/sys_enter")
+int store_release(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+
+#ifdef __BPF_FEATURE_LOAD_ACQ_STORE_REL
+	__u8 val8 = 0x12;
+	__u16 val16 = 0x1234;
+	__u32 val32 = 0x12345678;
+	__u64 val64 = 0x1234567890abcdef;
+
+	__atomic_store_n(&store_release8_result, val8, __ATOMIC_RELEASE);
+	__atomic_store_n(&store_release16_result, val16, __ATOMIC_RELEASE);
+	__atomic_store_n(&store_release32_result, val32, __ATOMIC_RELEASE);
+	__atomic_store_n(&store_release64_result, val64, __ATOMIC_RELEASE);
+#endif
+
+	return 0;
+}
+
 char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/atomics.c

@@ -5,9 +5,15 @@
 #include <stdbool.h>
 
 #ifdef ENABLE_ATOMICS_TESTS
-bool skip_tests __attribute((__section__(".data"))) = false;
+bool skip_all_tests __attribute((__section__(".data"))) = false;
 #else
-bool skip_tests = true;
+bool skip_all_tests = true;
+#endif
+
+#ifdef __BPF_FEATURE_LOAD_ACQ_STORE_REL
+bool skip_lacq_srel_tests __attribute((__section__(".data"))) = false;
+#else
+bool skip_lacq_srel_tests = true;
 #endif
 
 __u32 pid = 0;
@@ -168,3 +174,55 @@ int xchg(const void *ctx)
 
 	return 0;
 }
+
+__u8 load_acquire8_value = 0x12;
+__u16 load_acquire16_value = 0x1234;
+__u32 load_acquire32_value = 0x12345678;
+__u64 load_acquire64_value = 0x1234567890abcdef;
+
+__u8 load_acquire8_result = 0;
+__u16 load_acquire16_result = 0;
+__u32 load_acquire32_result = 0;
+__u64 load_acquire64_result = 0;
+
+SEC("raw_tp/sys_enter")
+int load_acquire(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+
+#ifdef __BPF_FEATURE_LOAD_ACQ_STORE_REL
+	load_acquire8_result = __atomic_load_n(&load_acquire8_value, __ATOMIC_ACQUIRE);
+	load_acquire16_result = __atomic_load_n(&load_acquire16_value, __ATOMIC_ACQUIRE);
+	load_acquire32_result = __atomic_load_n(&load_acquire32_value, __ATOMIC_ACQUIRE);
+	load_acquire64_result = __atomic_load_n(&load_acquire64_value, __ATOMIC_ACQUIRE);
+#endif
+
+	return 0;
+}
+
+__u8 store_release8_result = 0;
+__u16 store_release16_result = 0;
+__u32 store_release32_result = 0;
+__u64 store_release64_result = 0;
+
+SEC("raw_tp/sys_enter")
+int store_release(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+
+#ifdef __BPF_FEATURE_LOAD_ACQ_STORE_REL
+	__u8 val8 = 0x12;
+	__u16 val16 = 0x1234;
+	__u32 val32 = 0x12345678;
+	__u64 val64 = 0x1234567890abcdef;
+
+	__atomic_store_n(&store_release8_result, val8, __ATOMIC_RELEASE);
+	__atomic_store_n(&store_release16_result, val16, __ATOMIC_RELEASE);
+	__atomic_store_n(&store_release32_result, val32, __ATOMIC_RELEASE);
+	__atomic_store_n(&store_release64_result, val64, __ATOMIC_RELEASE);
+#endif
+
+	return 0;
+}

tools/testing/selftests/bpf/verifier/atomic_invalid.c

@@ -1,4 +1,4 @@
-#define __INVALID_ATOMIC_ACCESS_TEST(op)				\
+#define __INVALID_ATOMIC_ACCESS_TEST(op, reg)				\
 	{								\
 		"atomic " #op " access through non-pointer ",		\
 		.insns = {						\
@@ -9,15 +9,17 @@
 			BPF_EXIT_INSN(),				\
 		},							\
 		.result = REJECT,					\
-		.errstr = "R1 invalid mem access 'scalar'"		\
+		.errstr = #reg " invalid mem access 'scalar'"		\
 	}
-__INVALID_ATOMIC_ACCESS_TEST(BPF_ADD),
-__INVALID_ATOMIC_ACCESS_TEST(BPF_ADD | BPF_FETCH),
-__INVALID_ATOMIC_ACCESS_TEST(BPF_AND),
-__INVALID_ATOMIC_ACCESS_TEST(BPF_AND | BPF_FETCH),
-__INVALID_ATOMIC_ACCESS_TEST(BPF_OR),
-__INVALID_ATOMIC_ACCESS_TEST(BPF_OR | BPF_FETCH),
-__INVALID_ATOMIC_ACCESS_TEST(BPF_XOR),
-__INVALID_ATOMIC_ACCESS_TEST(BPF_XOR | BPF_FETCH),
-__INVALID_ATOMIC_ACCESS_TEST(BPF_XCHG),
-__INVALID_ATOMIC_ACCESS_TEST(BPF_CMPXCHG),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_ADD, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_ADD | BPF_FETCH, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_AND, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_AND | BPF_FETCH, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_OR, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_OR | BPF_FETCH, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_XOR, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_XOR | BPF_FETCH, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_XCHG, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_CMPXCHG, R1),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_LOAD_ACQ, R0),
+__INVALID_ATOMIC_ACCESS_TEST(BPF_STORE_REL, R1),