Add several self-tests to test the new instructions and the new
BPF_STATIC_BRANCH_UPDATE syscall.
Signed-off-by: Anton Protopopov <aspsk@xxxxxxxxxxxxx>
---
.../bpf/prog_tests/bpf_static_branches.c | 269 ++++++++++++++++++
1 file changed, 269 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_static_branches.c
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_static_branches.c b/tools/testing/selftests/bpf/prog_tests/bpf_static_branches.c
new file mode 100644
index 000000000000..6f54002e6e15
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_static_branches.c
@@ -0,0 +1,269 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Isovalent */
+
+#include <test_progs.h>
+
+#include <sys/syscall.h>
+#include <bpf/bpf.h>
+
+static inline int _bpf_prog_load(struct bpf_insn *insns, __u32 insn_cnt)
+{
+ union bpf_attr attr = {
+ .prog_type = BPF_PROG_TYPE_XDP, /* we don't care */
+ .insns = ptr_to_u64(insns),
+ .insn_cnt = insn_cnt,
+ .license = ptr_to_u64("GPL"),
+ };
+
+ return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
+}
+
+enum {
+ OFF,
+ ON
+};
+
+static inline int bpf_static_branch_update(int prog_fd, __u32 insn_off, __u32 on)
+{
+ union bpf_attr attr = {
+ .static_branch.prog_fd = (__u32)prog_fd,
+ .static_branch.insn_off = insn_off,
+ .static_branch.on = on,
+ };
+
+ return syscall(__NR_bpf, BPF_STATIC_BRANCH_UPDATE, &attr, sizeof(attr));
+}
+
+#define BPF_JMP32_OR_NOP(IMM, OFF) \
+ ((struct bpf_insn) { \
+ .code = BPF_JMP32 | BPF_JA | BPF_K, \
+ .dst_reg = 0, \
+ .src_reg = BPF_STATIC_BRANCH_JA, \
+ .off = OFF, \
+ .imm = IMM })
+
+#define BPF_JMP_OR_NOP(IMM, OFF) \
+ ((struct bpf_insn) { \
+ .code = BPF_JMP | BPF_JA | BPF_K, \
+ .dst_reg = 0, \
+ .src_reg = BPF_STATIC_BRANCH_JA, \
+ .off = OFF, \
+ .imm = IMM })
+
+#define BPF_NOP_OR_JMP32(IMM, OFF) \
+ ((struct bpf_insn) { \
+ .code = BPF_JMP32 | BPF_JA | BPF_K, \
+ .dst_reg = 0, \
+ .src_reg = BPF_STATIC_BRANCH_JA | \
+ BPF_STATIC_BRANCH_NOP, \
+ .off = OFF, \
+ .imm = IMM })
+
+#define BPF_NOP_OR_JMP(IMM, OFF) \
+ ((struct bpf_insn) { \
+ .code = BPF_JMP | BPF_JA | BPF_K, \
+ .dst_reg = 0, \
+ .src_reg = BPF_STATIC_BRANCH_JA | \
+ BPF_STATIC_BRANCH_NOP, \
+ .off = OFF, \
+ .imm = IMM })
+
+static const struct bpf_insn insns0[] = {
+ BPF_JMP_OR_NOP(0, 1),
+ BPF_NOP_OR_JMP(0, 1),
+ BPF_JMP32_OR_NOP(1, 0),
+ BPF_NOP_OR_JMP32(1, 0),
+};
+
+static void check_ops(void)
+{
+ struct bpf_insn insns[] = {
+ {}, /* we will substitute this by insn0[i], i=0,1,2,3 */
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, -2),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ };
+ union bpf_attr attr = {
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .insns = ptr_to_u64(insns),
+ .insn_cnt = ARRAY_SIZE(insns),
+ .license = ptr_to_u64("GPL"),
+ };
+ bool stop = false;
+ int prog_fd[4];
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ insns[0] = insns0[i];
+ prog_fd[i] = _bpf_prog_load(insns, ARRAY_SIZE(insns));
+ if (!ASSERT_GE(prog_fd[i], 0, "correct program"))
+ stop = true;
+ }
+
+ for (i = 0; i < 4; i++)
+ close(prog_fd[i]);
+
+ if (stop)
+ return;
+
+ /* load should fail: incorrect SRC */
+ for (i = 0; i < 4; i++) {
+ insns[0] = insns0[i];
+ insns[0].src_reg |= 4;
+ prog_fd[i] = _bpf_prog_load(insns, ARRAY_SIZE(insns));
+ if (!ASSERT_EQ(prog_fd[i], -1, "incorrect src"))
+ return;
+ }
+
+ /* load should fail: incorrect DST */
+ for (i = 0; i < 4; i++) {
+ insns[0] = insns0[i];
+ insns[0].dst_reg = i + 1; /* non-zero */
+ prog_fd[i] = _bpf_prog_load(insns, ARRAY_SIZE(insns));
+ if (!ASSERT_EQ(prog_fd[i], -1, "incorrect dst"))
+ return;
+ }
+
+ /* load should fail: both off and imm are set */
+ for (i = 0; i < 4; i++) {
+ insns[0] = insns0[i];
+ insns[0].imm = insns[0].off = insns0[i].imm ?: insns0[i].off;
+ prog_fd[i] = _bpf_prog_load(insns, ARRAY_SIZE(insns));
+ if (!ASSERT_EQ(prog_fd[i], -1, "incorrect imm/off"))
+ return;
+ }
+
+ /* load should fail: offset is incorrect */
+ for (i = 0; i < 4; i++) {
+ insns[0] = insns0[i];
+
+ if (insns0[i].imm)
+ insns[0].imm = -2;
+ else
+ insns[0].off = -2;
+ prog_fd[i] = _bpf_prog_load(insns, ARRAY_SIZE(insns));
+ if (!ASSERT_EQ(prog_fd[i], -1, "incorrect imm/off"))
+ return;
+
+ if (insns0[i].imm)
+ insns[0].imm = 42;
+ else
+ insns[0].off = 42;
+ prog_fd[i] = _bpf_prog_load(insns, ARRAY_SIZE(insns));
+ if (!ASSERT_EQ(prog_fd[i], -1, "incorrect imm/off"))
+ return;
+
+ /* 0 is not allowed */
+ insns[0].imm = insns[0].off = 0;
+ prog_fd[i] = _bpf_prog_load(insns, ARRAY_SIZE(insns));
+ if (!ASSERT_EQ(prog_fd[i], -1, "incorrect imm/off"))
+ return;
+ }
+
+ /* incorrect field is used */
+ for (i = 0; i < 4; i++) {
+ int tmp;
+
+ insns[0] = insns0[i];
+
+ tmp = insns[0].imm;
+ insns[0].imm = insns[0].off;
+ insns[0].off = tmp;
+
+ prog_fd[i] = _bpf_prog_load(insns, ARRAY_SIZE(insns));
+ if (!ASSERT_EQ(prog_fd[i], -1, "incorrect field"))
+ return;
+ }
+}
+
+static void check_syscall(void)
+{
+ struct bpf_insn insns[] = {
+ {}, /* we will substitute this by insn0[i], i=0,1,2,3 */
+ BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+ BPF_JMP_IMM(BPF_JA, 0, 0, -2),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ };
+ union bpf_attr attr = {
+ .prog_type = BPF_PROG_TYPE_XDP,
+ .insns = ptr_to_u64(insns),
+ .insn_cnt = ARRAY_SIZE(insns),
+ .license = ptr_to_u64("GPL"),
+ };
+ bool stop = false;
+ int prog_fd[4];
+ __u32 insn_off;
+ int ret;
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ insns[0] = insns0[i];
+ prog_fd[i] = _bpf_prog_load(insns, ARRAY_SIZE(insns));
+ if (!ASSERT_GE(prog_fd[i], 0, "correct program"))
+ stop = true;
+ }
+
+ if (stop)
+ goto end;
+
+ for (i = 0; i < 4; i++) {
+ /* we can set branch off */
+ ret = bpf_static_branch_update(prog_fd[i], 0, OFF);
+ if (!ASSERT_EQ(ret, 0, "correct update"))
+ goto end;
+
+ /* we can set branch on */
+ ret = bpf_static_branch_update(prog_fd[i], 0, ON);
+ if (!ASSERT_EQ(ret, 0, "correct update"))
+ goto end;
+
+ /* incorrect.static_branch.on: can only be 0|1 */
+ ret = bpf_static_branch_update(prog_fd[i], 0, 2);
+ if (!ASSERT_EQ(ret, -1, "incorrect static_branch.on value"))
+ goto end;
+
+ /* incorrect static_branch.insn_off: can only be 0 in this case */
+ for (insn_off = 1; insn_off < 5; insn_off++) {
+ ret = bpf_static_branch_update(prog_fd[i], insn_off, OFF);
+ if (!ASSERT_EQ(ret, -1, "incorrect insn_off: not a correct insns"))
+ goto end;
+ if (!ASSERT_EQ(errno, EINVAL, "incorrect insn_off: not a correct insns"))
+ goto end;
+ }
+ ret = bpf_static_branch_update(prog_fd[i], 666, OFF);
+ if (!ASSERT_EQ(ret, -1, "incorrect insn_off: out of range"))
+ goto end;
+ if (!ASSERT_EQ(errno, ERANGE, "incorrect insn_off: out puf range"))
+ goto end;
+
+ /* bad file descriptor: no open file */
+ ret = bpf_static_branch_update(-1, 0, OFF);
+ if (!ASSERT_EQ(ret, -1, "incorrect prog_fd: no file"))
+ goto end;
+ if (!ASSERT_EQ(errno, EBADF, "incorrect prog_fd: no file"))
+ goto end;
+
+ /* bad file descriptor: not a bpf prog */
+ ret = bpf_static_branch_update(0, 0, OFF);
+ if (!ASSERT_EQ(ret, -1, "incorrect prog_fd: not a bpf prog"))
+ goto end;
+ if (!ASSERT_EQ(errno, EINVAL, "incorrect prog_fd: not a bpf prog"))
+ goto end;
+ }
+
+end:
+ for (i = 0; i < 4; i++)
+ close(prog_fd[i]);
+
+}
+
+void test_bpf_static_branches(void)
+{
+ if (test__start_subtest("check_ops"))
+ check_ops();
+
+ if (test__start_subtest("check_syscall"))
+ check_syscall();
+}
--
2.34.1
