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bpf: Add tests for new BPF atomic operations
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The prog_test that's added depends on Clang/LLVM features added by
Yonghong in commit 286daafd6512 (was https://reviews.llvm.org/D72184).

Note the use of a define called ENABLE_ATOMICS_TESTS: this is used
to:

 - Avoid breaking the build for people on old versions of Clang
 - Avoid needing separate lists of test objects for no_alu32, where
   atomics are not supported even if Clang has the feature.

The atomics_test.o BPF object is built unconditionally both for
test_progs and test_progs-no_alu32. For test_progs, if Clang supports
atomics, ENABLE_ATOMICS_TESTS is defined, so it includes the proper
test code. Otherwise, progs and global vars are defined anyway, as
stubs; this means that the skeleton user code still builds.

The atomics_test.o userspace object is built once and used for both
test_progs and test_progs-no_alu32. A variable called skip_tests is
defined in the BPF object's data section, which tells the userspace
object whether to skip the atomics test.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210114181751.768687-11-jackmanb@google.com
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Brendan Jackman authored and Alexei Starovoitov committed Jan 15, 2021
1 parent 981f94c commit 98d666d
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2 changes: 2 additions & 0 deletions tools/testing/selftests/bpf/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -414,10 +414,12 @@ TRUNNER_EXTRA_FILES := $(OUTPUT)/urandom_read $(OUTPUT)/bpf_testmod.ko \
$(wildcard progs/btf_dump_test_case_*.c)
TRUNNER_BPF_BUILD_RULE := CLANG_BPF_BUILD_RULE
TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(CLANG_CFLAGS)
TRUNNER_BPF_CFLAGS += -DENABLE_ATOMICS_TESTS
$(eval $(call DEFINE_TEST_RUNNER,test_progs))

# Define test_progs-no_alu32 test runner.
TRUNNER_BPF_BUILD_RULE := CLANG_NOALU32_BPF_BUILD_RULE
TRUNNER_BPF_CFLAGS := $(BPF_CFLAGS) $(CLANG_CFLAGS)
$(eval $(call DEFINE_TEST_RUNNER,test_progs,no_alu32))

# Define test_progs BPF-GCC-flavored test runner.
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246 changes: 246 additions & 0 deletions tools/testing/selftests/bpf/prog_tests/atomics.c
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@@ -0,0 +1,246 @@
// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>

#include "atomics.skel.h"

static void test_add(struct atomics *skel)
{
int err, prog_fd;
__u32 duration = 0, retval;
struct bpf_link *link;

link = bpf_program__attach(skel->progs.add);
if (CHECK(IS_ERR(link), "attach(add)", "err: %ld\n", PTR_ERR(link)))
return;

prog_fd = bpf_program__fd(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;

ASSERT_EQ(skel->data->add64_value, 3, "add64_value");
ASSERT_EQ(skel->bss->add64_result, 1, "add64_result");

ASSERT_EQ(skel->data->add32_value, 3, "add32_value");
ASSERT_EQ(skel->bss->add32_result, 1, "add32_result");

ASSERT_EQ(skel->bss->add_stack_value_copy, 3, "add_stack_value");
ASSERT_EQ(skel->bss->add_stack_result, 1, "add_stack_result");

ASSERT_EQ(skel->data->add_noreturn_value, 3, "add_noreturn_value");

cleanup:
bpf_link__destroy(link);
}

static void test_sub(struct atomics *skel)
{
int err, prog_fd;
__u32 duration = 0, retval;
struct bpf_link *link;

link = bpf_program__attach(skel->progs.sub);
if (CHECK(IS_ERR(link), "attach(sub)", "err: %ld\n", PTR_ERR(link)))
return;

prog_fd = bpf_program__fd(skel->progs.sub);
err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
NULL, NULL, &retval, &duration);
if (CHECK(err || retval, "test_run sub",
"err %d errno %d retval %d duration %d\n",
err, errno, retval, duration))
goto cleanup;

ASSERT_EQ(skel->data->sub64_value, -1, "sub64_value");
ASSERT_EQ(skel->bss->sub64_result, 1, "sub64_result");

ASSERT_EQ(skel->data->sub32_value, -1, "sub32_value");
ASSERT_EQ(skel->bss->sub32_result, 1, "sub32_result");

ASSERT_EQ(skel->bss->sub_stack_value_copy, -1, "sub_stack_value");
ASSERT_EQ(skel->bss->sub_stack_result, 1, "sub_stack_result");

ASSERT_EQ(skel->data->sub_noreturn_value, -1, "sub_noreturn_value");

cleanup:
bpf_link__destroy(link);
}

static void test_and(struct atomics *skel)
{
int err, prog_fd;
__u32 duration = 0, retval;
struct bpf_link *link;

link = bpf_program__attach(skel->progs.and);
if (CHECK(IS_ERR(link), "attach(and)", "err: %ld\n", PTR_ERR(link)))
return;

prog_fd = bpf_program__fd(skel->progs.and);
err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
NULL, NULL, &retval, &duration);
if (CHECK(err || retval, "test_run and",
"err %d errno %d retval %d duration %d\n", err, errno, retval, duration))
goto cleanup;

ASSERT_EQ(skel->data->and64_value, 0x010ull << 32, "and64_value");
ASSERT_EQ(skel->bss->and64_result, 0x110ull << 32, "and64_result");

ASSERT_EQ(skel->data->and32_value, 0x010, "and32_value");
ASSERT_EQ(skel->bss->and32_result, 0x110, "and32_result");

ASSERT_EQ(skel->data->and_noreturn_value, 0x010ull << 32, "and_noreturn_value");
cleanup:
bpf_link__destroy(link);
}

static void test_or(struct atomics *skel)
{
int err, prog_fd;
__u32 duration = 0, retval;
struct bpf_link *link;

link = bpf_program__attach(skel->progs.or);
if (CHECK(IS_ERR(link), "attach(or)", "err: %ld\n", PTR_ERR(link)))
return;

prog_fd = bpf_program__fd(skel->progs.or);
err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
NULL, NULL, &retval, &duration);
if (CHECK(err || retval, "test_run or",
"err %d errno %d retval %d duration %d\n",
err, errno, retval, duration))
goto cleanup;

ASSERT_EQ(skel->data->or64_value, 0x111ull << 32, "or64_value");
ASSERT_EQ(skel->bss->or64_result, 0x110ull << 32, "or64_result");

ASSERT_EQ(skel->data->or32_value, 0x111, "or32_value");
ASSERT_EQ(skel->bss->or32_result, 0x110, "or32_result");

ASSERT_EQ(skel->data->or_noreturn_value, 0x111ull << 32, "or_noreturn_value");
cleanup:
bpf_link__destroy(link);
}

static void test_xor(struct atomics *skel)
{
int err, prog_fd;
__u32 duration = 0, retval;
struct bpf_link *link;

link = bpf_program__attach(skel->progs.xor);
if (CHECK(IS_ERR(link), "attach(xor)", "err: %ld\n", PTR_ERR(link)))
return;

prog_fd = bpf_program__fd(skel->progs.xor);
err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
NULL, NULL, &retval, &duration);
if (CHECK(err || retval, "test_run xor",
"err %d errno %d retval %d duration %d\n", err, errno, retval, duration))
goto cleanup;

ASSERT_EQ(skel->data->xor64_value, 0x101ull << 32, "xor64_value");
ASSERT_EQ(skel->bss->xor64_result, 0x110ull << 32, "xor64_result");

ASSERT_EQ(skel->data->xor32_value, 0x101, "xor32_value");
ASSERT_EQ(skel->bss->xor32_result, 0x110, "xor32_result");

ASSERT_EQ(skel->data->xor_noreturn_value, 0x101ull << 32, "xor_nxoreturn_value");
cleanup:
bpf_link__destroy(link);
}

static void test_cmpxchg(struct atomics *skel)
{
int err, prog_fd;
__u32 duration = 0, retval;
struct bpf_link *link;

link = bpf_program__attach(skel->progs.cmpxchg);
if (CHECK(IS_ERR(link), "attach(cmpxchg)", "err: %ld\n", PTR_ERR(link)))
return;

prog_fd = bpf_program__fd(skel->progs.cmpxchg);
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;

ASSERT_EQ(skel->data->cmpxchg64_value, 2, "cmpxchg64_value");
ASSERT_EQ(skel->bss->cmpxchg64_result_fail, 1, "cmpxchg_result_fail");
ASSERT_EQ(skel->bss->cmpxchg64_result_succeed, 1, "cmpxchg_result_succeed");

ASSERT_EQ(skel->data->cmpxchg32_value, 2, "lcmpxchg32_value");
ASSERT_EQ(skel->bss->cmpxchg32_result_fail, 1, "cmpxchg_result_fail");
ASSERT_EQ(skel->bss->cmpxchg32_result_succeed, 1, "cmpxchg_result_succeed");

cleanup:
bpf_link__destroy(link);
}

static void test_xchg(struct atomics *skel)
{
int err, prog_fd;
__u32 duration = 0, retval;
struct bpf_link *link;

link = bpf_program__attach(skel->progs.xchg);
if (CHECK(IS_ERR(link), "attach(xchg)", "err: %ld\n", PTR_ERR(link)))
return;

prog_fd = bpf_program__fd(skel->progs.xchg);
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;

ASSERT_EQ(skel->data->xchg64_value, 2, "xchg64_value");
ASSERT_EQ(skel->bss->xchg64_result, 1, "xchg64_result");

ASSERT_EQ(skel->data->xchg32_value, 2, "xchg32_value");
ASSERT_EQ(skel->bss->xchg32_result, 1, "xchg32_result");

cleanup:
bpf_link__destroy(link);
}

void test_atomics(void)
{
struct atomics *skel;
__u32 duration = 0;

skel = atomics__open_and_load();
if (CHECK(!skel, "skel_load", "atomics skeleton failed\n"))
return;

if (skel->data->skip_tests) {
printf("%s:SKIP:no ENABLE_ATOMICS_TESTS (missing Clang BPF atomics support)",
__func__);
test__skip();
goto cleanup;
}

if (test__start_subtest("add"))
test_add(skel);
if (test__start_subtest("sub"))
test_sub(skel);
if (test__start_subtest("and"))
test_and(skel);
if (test__start_subtest("or"))
test_or(skel);
if (test__start_subtest("xor"))
test_xor(skel);
if (test__start_subtest("cmpxchg"))
test_cmpxchg(skel);
if (test__start_subtest("xchg"))
test_xchg(skel);

cleanup:
atomics__destroy(skel);
}
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