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Diffstat (limited to 'tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c')
-rw-r--r--tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c b/tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c
index 2efd8bcf57a1..6e52dfc64415 100644
--- a/tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c
+++ b/tools/testing/selftests/bpf/verifier/atomic_cmpxchg.c
@@ -94,3 +94,28 @@
.result = REJECT,
.errstr = "invalid read from stack",
},
+{
+ "BPF_W cmpxchg should zero top 32 bits",
+ .insns = {
+ /* r0 = U64_MAX; */
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_0, 1),
+ /* u64 val = r0; */
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+ /* r0 = (u32)atomic_cmpxchg((u32 *)&val, r0, 1); */
+ BPF_MOV32_IMM(BPF_REG_1, 1),
+ BPF_ATOMIC_OP(BPF_W, BPF_CMPXCHG, BPF_REG_10, BPF_REG_1, -8),
+ /* r1 = 0x00000000FFFFFFFFull; */
+ BPF_MOV64_IMM(BPF_REG_1, 1),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_1, 32),
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_1, 1),
+ /* if (r0 != r1) exit(1); */
+ BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_1, 2),
+ BPF_MOV32_IMM(BPF_REG_0, 1),
+ BPF_EXIT_INSN(),
+ /* exit(0); */
+ BPF_MOV32_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+},