diff options
| author | Yonghong Song <yonghong.song@linux.dev> | 2023-07-27 18:12:19 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-07-27 18:52:33 -0700 |
| commit | ec0e2da95f72d4a46050a4d994e4fe471474fd80 (patch) | |
| tree | f61640998fc71caa7506d67a1bd2668ca1adcce6 /arch/x86/net/bpf_jit_comp.c | |
| parent | 0845c3db7bf5c4ceb7100bcd8fd594d9ccf3c29a (diff) | |
bpf: Support new signed div/mod instructions.
Add interpreter/jit support for new signed div/mod insns.
The new signed div/mod instructions are encoded with
unsigned div/mod instructions plus insn->off == 1.
Also add basic verifier support to ensure new insns get
accepted.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011219.3714605-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'arch/x86/net/bpf_jit_comp.c')
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 4942a4c188b9..a89b62eb2b40 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1194,15 +1194,26 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image /* mov rax, dst_reg */ emit_mov_reg(&prog, is64, BPF_REG_0, dst_reg); - /* - * xor edx, edx - * equivalent to 'xor rdx, rdx', but one byte less - */ - EMIT2(0x31, 0xd2); + if (insn->off == 0) { + /* + * xor edx, edx + * equivalent to 'xor rdx, rdx', but one byte less + */ + EMIT2(0x31, 0xd2); - /* div src_reg */ - maybe_emit_1mod(&prog, src_reg, is64); - EMIT2(0xF7, add_1reg(0xF0, src_reg)); + /* div src_reg */ + maybe_emit_1mod(&prog, src_reg, is64); + EMIT2(0xF7, add_1reg(0xF0, src_reg)); + } else { + if (BPF_CLASS(insn->code) == BPF_ALU) + EMIT1(0x99); /* cdq */ + else + EMIT2(0x48, 0x99); /* cqo */ + + /* idiv src_reg */ + maybe_emit_1mod(&prog, src_reg, is64); + EMIT2(0xF7, add_1reg(0xF8, src_reg)); + } if (BPF_OP(insn->code) == BPF_MOD && dst_reg != BPF_REG_3) |