From: "Naveen N. Rao" naveen.n.rao@linux.vnet.ibm.com
upstream commit 5855c4c1f415ca3ba1046e77c0b3d3dfc96c9025
We aren't handling subtraction involving an immediate value of 0x80000000 properly. Fix the same.
Fixes: 156d0e290e969c ("powerpc/ebpf/jit: Implement JIT compiler for extended BPF") Signed-off-by: Naveen N. Rao naveen.n.rao@linux.vnet.ibm.com Reviewed-by: Christophe Leroy christophe.leroy@csgroup.eu [mpe: Fold in fix from Naveen to use imm <= 32768] Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/fc4b1276eb10761fd7ce0814c8dd089da2815251.163346414... [adjust macros to account for commits 0654186510a40e and 3a181237916310] Signed-off-by: Naveen N. Rao naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/net/bpf_jit_comp64.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-)
--- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -326,18 +326,25 @@ static int bpf_jit_build_body(struct bpf PPC_SUB(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU | BPF_ADD | BPF_K: /* (u32) dst += (u32) imm */ - case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */ case BPF_ALU64 | BPF_ADD | BPF_K: /* dst += imm */ + if (!imm) { + goto bpf_alu32_trunc; + } else if (imm >= -32768 && imm < 32768) { + PPC_ADDI(dst_reg, dst_reg, IMM_L(imm)); + } else { + PPC_LI32(b2p[TMP_REG_1], imm); + PPC_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]); + } + goto bpf_alu32_trunc; + case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */ case BPF_ALU64 | BPF_SUB | BPF_K: /* dst -= imm */ - if (BPF_OP(code) == BPF_SUB) - imm = -imm; - if (imm) { - if (imm >= -32768 && imm < 32768) - PPC_ADDI(dst_reg, dst_reg, IMM_L(imm)); - else { - PPC_LI32(b2p[TMP_REG_1], imm); - PPC_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]); - } + if (!imm) { + goto bpf_alu32_trunc; + } else if (imm > -32768 && imm <= 32768) { + PPC_ADDI(dst_reg, dst_reg, IMM_L(-imm)); + } else { + PPC_LI32(b2p[TMP_REG_1], imm); + PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]); } goto bpf_alu32_trunc; case BPF_ALU | BPF_MUL | BPF_X: /* (u32) dst *= (u32) src */