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powerpc/bpf: use unsigned division instruction for 64-bit operations

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BPF_ALU64 div/mod operations are currently using signed division, unlike
BPF_ALU32 operations. Fix the same. DIV64 and MOD64 overflow tests pass
with this fix.

Fixes: 156d0e290e ("powerpc/ebpf/jit: Implement JIT compiler for extended BPF")
Cc: stable@vger.kernel.org # v4.8+
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Naveen N. Rao
2019-06-13 00:21:40 +05:30
committed by Daniel Borkmann
parent 3e06826951
commit 758f2046ea
3 changed files with 6 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
arch/powerpc/net/bpf_jit_comp64.c
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@@ -399,12 +399,12 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
case BPF_ALU64 | BPF_DIV | BPF_X: /* dst /= src */
case BPF_ALU64 | BPF_MOD | BPF_X: /* dst %= src */
if (BPF_OP(code) == BPF_MOD) {
PPC_DIVD(b2p[TMP_REG_1], dst_reg, src_reg);
PPC_DIVDU(b2p[TMP_REG_1], dst_reg, src_reg);
PPC_MULD(b2p[TMP_REG_1], src_reg,
b2p[TMP_REG_1]);
PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]);
} else
PPC_DIVD(dst_reg, dst_reg, src_reg);
PPC_DIVDU(dst_reg, dst_reg, src_reg);
break;
case BPF_ALU | BPF_MOD | BPF_K: /* (u32) dst %= (u32) imm */
case BPF_ALU | BPF_DIV | BPF_K: /* (u32) dst /= (u32) imm */
@@ -432,7 +432,7 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
break;
case BPF_ALU64:
if (BPF_OP(code) == BPF_MOD) {
PPC_DIVD(b2p[TMP_REG_2], dst_reg,
PPC_DIVDU(b2p[TMP_REG_2], dst_reg,
b2p[TMP_REG_1]);
PPC_MULD(b2p[TMP_REG_1],
b2p[TMP_REG_1],
@@ -440,7 +440,7 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
PPC_SUB(dst_reg, dst_reg,
b2p[TMP_REG_1]);
} else
PPC_DIVD(dst_reg, dst_reg,
PPC_DIVDU(dst_reg, dst_reg,
b2p[TMP_REG_1]);
break;
}