This is a note to let you know that I've just added the patch titled powerpc/bpf: Fix BPF_SUB when imm == 0x80000000 to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-bpf-fix-bpf_sub-when-imm-0x80000000.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 2ab892bd24a51611c0f5d9c994dcfe261f38377f Author: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Date: Wed Oct 6 01:55:23 2021 +0530 powerpc/bpf: Fix BPF_SUB when imm == 0x80000000 [ 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@xxxxxxxxxxxxxxxxxx> Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> [mpe: Fold in fix from Naveen to use imm <= 32768] Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/fc4b1276eb10761fd7ce0814c8dd089da2815251.1633464148.git.naveen.n.rao@xxxxxxxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index e79f9eae2bc0..a2750d6ffd0f 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -347,18 +347,25 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, EMIT(PPC_RAW_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) { + EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(imm))); + } else { + PPC_LI32(b2p[TMP_REG_1], imm); + EMIT(PPC_RAW_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) - EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(imm))); - else { - PPC_LI32(b2p[TMP_REG_1], imm); - EMIT(PPC_RAW_ADD(dst_reg, dst_reg, b2p[TMP_REG_1])); - } + if (!imm) { + goto bpf_alu32_trunc; + } else if (imm > -32768 && imm <= 32768) { + EMIT(PPC_RAW_ADDI(dst_reg, dst_reg, IMM_L(-imm))); + } else { + PPC_LI32(b2p[TMP_REG_1], imm); + EMIT(PPC_RAW_SUB(dst_reg, dst_reg, b2p[TMP_REG_1])); } goto bpf_alu32_trunc; case BPF_ALU | BPF_MUL | BPF_X: /* (u32) dst *= (u32) src */