| From 2ab892bd24a51611c0f5d9c994dcfe261f38377f Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Wed, 6 Oct 2021 01:55:23 +0530 |
| Subject: powerpc/bpf: Fix BPF_SUB when imm == 0x80000000 |
| |
| 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/fc4b1276eb10761fd7ce0814c8dd089da2815251.1633464148.git.naveen.n.rao@linux.vnet.ibm.com |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/powerpc/net/bpf_jit_comp64.c | 27 +++++++++++++++++---------- |
| 1 file changed, 17 insertions(+), 10 deletions(-) |
| |
| 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 */ |
| -- |
| 2.33.0 |
| |