'shift by register' operations are supported by eBPF interpreter, but were
accidently left out of x64 JIT compiler. Fix it and add a testcase.
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
---
arch/x86/net/bpf_jit_comp.c | 42 ++++++++++++++++++++++++++++++++++++++++++
lib/test_bpf.c | 38 ++++++++++++++++++++++++++++++++++++++
2 files changed, 80 insertions(+)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 5c8cb8043c5a..b08a98c59530 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -515,6 +515,48 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
EMIT3(0xC1, add_1reg(b3, dst_reg), imm32);
break;
+ case BPF_ALU | BPF_LSH | BPF_X:
+ case BPF_ALU | BPF_RSH | BPF_X:
+ case BPF_ALU | BPF_ARSH | BPF_X:
+ case BPF_ALU64 | BPF_LSH | BPF_X:
+ case BPF_ALU64 | BPF_RSH | BPF_X:
+ case BPF_ALU64 | BPF_ARSH | BPF_X:
+
+ /* check for bad case when dst_reg == rcx */
+ if (dst_reg == BPF_REG_4) {
+ /* mov r11, dst_reg */
+ EMIT_mov(AUX_REG, dst_reg);
+ dst_reg = AUX_REG;
+ }
+
+ if (src_reg != BPF_REG_4) { /* common case */
+ EMIT1(0x51); /* push rcx */
+
+ /* mov rcx, src_reg */
+ EMIT_mov(BPF_REG_4, src_reg);
+ }
+
+ /* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */
+ if (BPF_CLASS(insn->code) == BPF_ALU64)
+ EMIT1(add_1mod(0x48, dst_reg));
+ else if (is_ereg(dst_reg))
+ EMIT1(add_1mod(0x40, dst_reg));
+
+ switch (BPF_OP(insn->code)) {
+ case BPF_LSH: b3 = 0xE0; break;
+ case BPF_RSH: b3 = 0xE8; break;
+ case BPF_ARSH: b3 = 0xF8; break;
+ }
+ EMIT2(0xD3, add_1reg(b3, dst_reg));
+
+ if (src_reg != BPF_REG_4)
+ EMIT1(0x59); /* pop rcx */
+
+ if (insn->dst_reg == BPF_REG_4)
+ /* mov dst_reg, r11 */
+ EMIT_mov(insn->dst_reg, AUX_REG);
+ break;
+
case BPF_ALU | BPF_END | BPF_FROM_BE:
switch (imm32) {
case 16:
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 89e0345733bd..8c66c6aace04 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -1342,6 +1342,44 @@ static struct bpf_test tests[] = {
{ { 0, -1 } }
},
{
+ "INT: shifts by register",
+ .u.insns_int = {
+ BPF_MOV64_IMM(R0, -1234),
+ BPF_MOV64_IMM(R1, 1),
+ BPF_ALU32_REG(BPF_RSH, R0, R1),
+ BPF_JMP_IMM(BPF_JEQ, R0, 0x7ffffd97, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(R2, 1),
+ BPF_ALU64_REG(BPF_LSH, R0, R2),
+ BPF_MOV32_IMM(R4, -1234),
+ BPF_JMP_REG(BPF_JEQ, R0, R4, 1),
+ BPF_EXIT_INSN(),
+ BPF_ALU64_IMM(BPF_AND, R4, 63),
+ BPF_ALU64_REG(BPF_LSH, R0, R4), /* R0 <= 46 */
+ BPF_MOV64_IMM(R3, 47),
+ BPF_ALU64_REG(BPF_ARSH, R0, R3),
+ BPF_JMP_IMM(BPF_JEQ, R0, -617, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(R2, 1),
+ BPF_ALU64_REG(BPF_LSH, R4, R2), /* R4 = 46 << 1 */
+ BPF_JMP_IMM(BPF_JEQ, R4, 92, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(R4, 4),
+ BPF_ALU64_REG(BPF_LSH, R4, R4), /* R4 = 4 << 4 */
+ BPF_JMP_IMM(BPF_JEQ, R4, 64, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(R4, 5),
+ BPF_ALU32_REG(BPF_LSH, R4, R4), /* R4 = 5 << 5 */
+ BPF_JMP_IMM(BPF_JEQ, R4, 160, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_IMM(R0, -1),
+ BPF_EXIT_INSN(),
+ },
+ INTERNAL,
+ { },
+ { { 0, -1 } }
+ },
+ {
"INT: DIV + ABS",
.u.insns_int = {
BPF_ALU64_REG(BPF_MOV, R6, R1),
--
1.7.9.5
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