selftests: bpf: add tests for shifts by zero

There are currently no tests for ALU64 shift operations when the shift
amount is 0. This adds 6 new tests to make sure they are equivalent
to a no-op. The x32 JIT had such bugs that could have been caught by
these tests.

Cc: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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

@@ -90,6 +90,91 @@
 	},
 	.result = ACCEPT,
 },
+{
+	"lsh64 by 0 imm",
+	.insns = {
+	BPF_LD_IMM64(BPF_REG_0, 1),
+	BPF_LD_IMM64(BPF_REG_1, 1),
+	BPF_ALU64_IMM(BPF_LSH, BPF_REG_1, 0),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+},
+{
+	"rsh64 by 0 imm",
+	.insns = {
+	BPF_LD_IMM64(BPF_REG_0, 1),
+	BPF_LD_IMM64(BPF_REG_1, 0x100000000LL),
+	BPF_ALU64_REG(BPF_MOV, BPF_REG_2, BPF_REG_1),
+	BPF_ALU64_IMM(BPF_RSH, BPF_REG_1, 0),
+	BPF_JMP_REG(BPF_JEQ, BPF_REG_1, BPF_REG_2, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+},
+{
+	"arsh64 by 0 imm",
+	.insns = {
+	BPF_LD_IMM64(BPF_REG_0, 1),
+	BPF_LD_IMM64(BPF_REG_1, 0x100000000LL),
+	BPF_ALU64_REG(BPF_MOV, BPF_REG_2, BPF_REG_1),
+	BPF_ALU64_IMM(BPF_ARSH, BPF_REG_1, 0),
+	BPF_JMP_REG(BPF_JEQ, BPF_REG_1, BPF_REG_2, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+},
+{
+	"lsh64 by 0 reg",
+	.insns = {
+	BPF_LD_IMM64(BPF_REG_0, 1),
+	BPF_LD_IMM64(BPF_REG_1, 1),
+	BPF_LD_IMM64(BPF_REG_2, 0),
+	BPF_ALU64_REG(BPF_LSH, BPF_REG_1, BPF_REG_2),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 1, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+},
+{
+	"rsh64 by 0 reg",
+	.insns = {
+	BPF_LD_IMM64(BPF_REG_0, 1),
+	BPF_LD_IMM64(BPF_REG_1, 0x100000000LL),
+	BPF_ALU64_REG(BPF_MOV, BPF_REG_2, BPF_REG_1),
+	BPF_LD_IMM64(BPF_REG_3, 0),
+	BPF_ALU64_REG(BPF_RSH, BPF_REG_1, BPF_REG_3),
+	BPF_JMP_REG(BPF_JEQ, BPF_REG_1, BPF_REG_2, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+},
+{
+	"arsh64 by 0 reg",
+	.insns = {
+	BPF_LD_IMM64(BPF_REG_0, 1),
+	BPF_LD_IMM64(BPF_REG_1, 0x100000000LL),
+	BPF_ALU64_REG(BPF_MOV, BPF_REG_2, BPF_REG_1),
+	BPF_LD_IMM64(BPF_REG_3, 0),
+	BPF_ALU64_REG(BPF_ARSH, BPF_REG_1, BPF_REG_3),
+	BPF_JMP_REG(BPF_JEQ, BPF_REG_1, BPF_REG_2, 1),
+	BPF_MOV64_IMM(BPF_REG_0, 2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 1,
+},
 {
 	"invalid 64-bit BPF_END",
 	.insns = {