On 11/23/20 9:32 AM, Brendan Jackman wrote:
This relies on the work done by Yonghong Song in
https://reviews.llvm.org/D72184
Signed-off-by: Brendan Jackman <jackmanb@xxxxxxxxxx>
---
tools/testing/selftests/bpf/Makefile | 2 +-
.../selftests/bpf/prog_tests/atomics_test.c | 145 ++++++++++++++++++
.../selftests/bpf/progs/atomics_test.c | 61 ++++++++
.../selftests/bpf/verifier/atomic_cmpxchg.c | 96 ++++++++++++
.../selftests/bpf/verifier/atomic_fetch_add.c | 106 +++++++++++++
.../selftests/bpf/verifier/atomic_xchg.c | 113 ++++++++++++++
6 files changed, 522 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/atomics_test.c
create mode 100644 tools/testing/selftests/bpf/progs/atomics_test.c
create mode 100644 tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c
create mode 100644 tools/testing/selftests/bpf/verifier/atomic_fetch_add.c
create mode 100644 tools/testing/selftests/bpf/verifier/atomic_xchg.c
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 3d5940cd110d..4e28640ca2d8 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -250,7 +250,7 @@ define CLANG_BPF_BUILD_RULE
$(call msg,CLNG-LLC,$(TRUNNER_BINARY),$2)
$(Q)($(CLANG) $3 -O2 -target bpf -emit-llvm \
-c $1 -o - || echo "BPF obj compilation failed") | \
- $(LLC) -mattr=dwarfris -march=bpf -mcpu=v3 $4 -filetype=obj -o $2
+ $(LLC) -mattr=dwarfris -march=bpf -mcpu=v4 $4 -filetype=obj -o $2
We have an issue here. If we change -mcpu=v4 here, we will force
people to use trunk llvm to run selftests which is not a good idea.
I am wondering whether we can single out progs/atomics_test.c, which
will be compiled with -mcpu=v4 and run with test_progs.
test_progs-no_alu32 runs tests without alu32. Since -mcpu=v4 implies
alu32, atomic tests should be skipped in test_progs-no-alu32.
In bpf_helpers.h, we already use __clang_major__ macro to compare
to clang version,
#if __clang_major__ >= 8 && defined(__bpf__)
static __always_inline void
bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
{
if (!__builtin_constant_p(slot))
__bpf_unreachable();
...
I think we could also use __clang_major__ in progs/atomics_test.c
to enable tested intrinsics only if __clang_major__ >= 12? This
way, the same code can be compiled with -mcpu=v2/v3.
Alternatively, you can also use a macro at clang command line like
clang -mcpu=v4 -DENABLE_ATOMIC ...
clang -mcpu=v3/v2 ...
progs/atomics_test.c:
#ifdef ENABLE_ATOMIC
... atomic_intrinsics ...
#endif
endef
# Similar to CLANG_BPF_BUILD_RULE, but with disabled alu32
define CLANG_NOALU32_BPF_BUILD_RULE
diff --git a/tools/testing/selftests/bpf/prog_tests/atomics_test.c b/tools/testing/selftests/bpf/prog_tests/atomics_test.c
new file mode 100644
index 000000000000..a4859d88fc11
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/atomics_test.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+
+#include "atomics_test.skel.h"
+
+static void test_add(void)
+{
+ struct atomics_test *atomics_skel = NULL;
+ int err, prog_fd;
+ __u32 duration = 0, retval;
+
+ atomics_skel = atomics_test__open_and_load();
+ if (CHECK(!atomics_skel, "atomics_skel_load", "atomics skeleton failed\n"))
+ goto cleanup;
+
+ err = atomics_test__attach(atomics_skel);
+ if (CHECK(err, "atomics_attach", "atomics attach failed: %d\n", err))
+ goto cleanup;
+
+ prog_fd = bpf_program__fd(atomics_skel->progs.add);
+ err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
+ NULL, NULL, &retval, &duration);
+ if (CHECK(err || retval, "test_run add",
+ "err %d errno %d retval %d duration %d\n",
+ err, errno, retval, duration))
+ goto cleanup;
+
+ CHECK(atomics_skel->data->add64_value != 3, "add64_value",
+ "64bit atomic add value was not incremented (got %lld want 2)\n",
+ atomics_skel->data->add64_value);
+ CHECK(atomics_skel->bss->add64_result != 1, "add64_result",
+ "64bit atomic add bad return value (got %lld want 1)\n",
+ atomics_skel->bss->add64_result);
+
+ CHECK(atomics_skel->data->add32_value != 3, "add32_value",
+ "32bit atomic add value was not incremented (got %d want 2)\n",
+ atomics_skel->data->add32_value);
+ CHECK(atomics_skel->bss->add32_result != 1, "add32_result",
+ "32bit atomic add bad return value (got %d want 1)\n",
+ atomics_skel->bss->add32_result);
+
+ CHECK(atomics_skel->bss->add_stack_value_copy != 3, "add_stack_value",
+ "_stackbit atomic add value was not incremented (got %lld want 2)\n",
+ atomics_skel->bss->add_stack_value_copy);
+ CHECK(atomics_skel->bss->add_stack_result != 1, "add_stack_result",
+ "_stackbit atomic add bad return value (got %lld want 1)\n",
+ atomics_skel->bss->add_stack_result);
+
+cleanup:
+ atomics_test__destroy(atomics_skel);
+}
+
[...]
diff --git a/tools/testing/selftests/bpf/progs/atomics_test.c b/tools/testing/selftests/bpf/progs/atomics_test.c
new file mode 100644
index 000000000000..d81f45eb6c45
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/atomics_test.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+__u64 add64_value = 1;
+__u64 add64_result;
+__u32 add32_value = 1;
+__u32 add32_result;
+__u64 add_stack_value_copy;
+__u64 add_stack_result;
To please llvm10, let us initialize all unitialized globals explicitly like
__u64 add64_result = 0;
__u32 add32_result = 0;
...
llvm11 and above are okay but llvm10 put those uninitialized globals
into COM section (not .bss or .data sections) which BTF did not
handle them.
+SEC("fentry/bpf_fentry_test1")
+int BPF_PROG(add, int a)
+{
+ __u64 add_stack_value = 1;
+
+ add64_result = __sync_fetch_and_add(&add64_value, 2);
+ add32_result = __sync_fetch_and_add(&add32_value, 2);
+ add_stack_result = __sync_fetch_and_add(&add_stack_value, 2);
+ add_stack_value_copy = add_stack_value;
+
+ return 0;
+}
+
+__u64 cmpxchg64_value = 1;
+__u64 cmpxchg64_result_fail;
+__u64 cmpxchg64_result_succeed;
+__u32 cmpxchg32_value = 1;
+__u32 cmpxchg32_result_fail;
+__u32 cmpxchg32_result_succeed;
same here. explicitly initializing cmpxchg64_result_fail,
cmpxchg64_result_succeed, cmpxchg32_result_fail, cmpxchg32_result_succeed.
+SEC("fentry/bpf_fentry_test1")
+int BPF_PROG(cmpxchg, int a)
+{
+ cmpxchg64_result_fail = __sync_val_compare_and_swap(
+ &cmpxchg64_value, 0, 3);
+ cmpxchg64_result_succeed = __sync_val_compare_and_swap(
+ &cmpxchg64_value, 1, 2);
+
+ cmpxchg32_result_fail = __sync_val_compare_and_swap(
+ &cmpxchg32_value, 0, 3);
+ cmpxchg32_result_succeed = __sync_val_compare_and_swap(
+ &cmpxchg32_value, 1, 2);
+
+ return 0;
+}
+
+__u64 xchg64_value = 1;
+__u64 xchg64_result;
+__u32 xchg32_value = 1;
+__u32 xchg32_result;
explicitly initializing xchg64_result, xchg32_result.
+SEC("fentry/bpf_fentry_test1")
+int BPF_PROG(xchg, int a)
+{
+ __u64 val64 = 2;
+ __u32 val32 = 2;
+
+ __atomic_exchange(&xchg64_value, &val64, &xchg64_result, __ATOMIC_RELAXED);
+ __atomic_exchange(&xchg32_value, &val32, &xchg32_result, __ATOMIC_RELAXED);
+
+ return 0;
+}
[...]
