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authorYonghong Song <yonghong.song@linux.dev>2023-07-27 18:12:19 -0700
committerAlexei Starovoitov <ast@kernel.org>2023-07-27 18:52:33 -0700
commitec0e2da95f72d4a46050a4d994e4fe471474fd80 (patch)
treef61640998fc71caa7506d67a1bd2668ca1adcce6 /arch/x86/net
parent0845c3db7bf5c4ceb7100bcd8fd594d9ccf3c29a (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')
-rw-r--r--arch/x86/net/bpf_jit_comp.c27
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)