From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: [PATCH net-next] bpf: x86: add missing 'shift by register' instructions to x64 eBPF JIT Date: Mon, 25 Aug 2014 12:27:02 -0700 Message-ID: <1408994822-14929-1-git-send-email-ast@plumgrid.com> Cc: Eric Dumazet , Daniel Borkmann , "H. Peter Anvin" , Brendan Gregg , netdev@vger.kernel.org To: "David S. Miller" Return-path: Received: from mail-pd0-f181.google.com ([209.85.192.181]:40713 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752351AbaHYT1O (ORCPT ); Mon, 25 Aug 2014 15:27:14 -0400 Received: by mail-pd0-f181.google.com with SMTP id g10so20906158pdj.12 for ; Mon, 25 Aug 2014 12:27:14 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: 'shift by register' operations are supported by eBPF interpreter, but were accidently left out of x64 JIT compiler. Fix it and add a testcase. Reported-by: Brendan Gregg Signed-off-by: Alexei Starovoitov Fixes: 622582786c9e ("net: filter: x86: internal BPF JIT") --- Probably not worth sending to stable, but wouldn't hurt either. arch/x86/net/bpf_jit_comp.c | 42 ++++++++++++++++++++++++++++++++++++++++++ lib/test_bpf.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 80 insertions(+) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 5c8cb8043c5a..b08a98c59530 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -515,6 +515,48 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, EMIT3(0xC1, add_1reg(b3, dst_reg), imm32); break; + case BPF_ALU | BPF_LSH | BPF_X: + case BPF_ALU | BPF_RSH | BPF_X: + case BPF_ALU | BPF_ARSH | BPF_X: + case BPF_ALU64 | BPF_LSH | BPF_X: + case BPF_ALU64 | BPF_RSH | BPF_X: + case BPF_ALU64 | BPF_ARSH | BPF_X: + + /* check for bad case when dst_reg == rcx */ + if (dst_reg == BPF_REG_4) { + /* mov r11, dst_reg */ + EMIT_mov(AUX_REG, dst_reg); + dst_reg = AUX_REG; + } + + if (src_reg != BPF_REG_4) { /* common case */ + EMIT1(0x51); /* push rcx */ + + /* mov rcx, src_reg */ + EMIT_mov(BPF_REG_4, src_reg); + } + + /* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */ + if (BPF_CLASS(insn->code) == BPF_ALU64) + EMIT1(add_1mod(0x48, dst_reg)); + else if (is_ereg(dst_reg)) + EMIT1(add_1mod(0x40, dst_reg)); + + switch (BPF_OP(insn->code)) { + case BPF_LSH: b3 = 0xE0; break; + case BPF_RSH: b3 = 0xE8; break; + case BPF_ARSH: b3 = 0xF8; break; + } + EMIT2(0xD3, add_1reg(b3, dst_reg)); + + if (src_reg != BPF_REG_4) + EMIT1(0x59); /* pop rcx */ + + if (insn->dst_reg == BPF_REG_4) + /* mov dst_reg, r11 */ + EMIT_mov(insn->dst_reg, AUX_REG); + break; + case BPF_ALU | BPF_END | BPF_FROM_BE: switch (imm32) { case 16: diff --git a/lib/test_bpf.c b/lib/test_bpf.c index 89e0345733bd..8c66c6aace04 100644 --- a/lib/test_bpf.c +++ b/lib/test_bpf.c @@ -1342,6 +1342,44 @@ static struct bpf_test tests[] = { { { 0, -1 } } }, { + "INT: shifts by register", + .u.insns_int = { + BPF_MOV64_IMM(R0, -1234), + BPF_MOV64_IMM(R1, 1), + BPF_ALU32_REG(BPF_RSH, R0, R1), + BPF_JMP_IMM(BPF_JEQ, R0, 0x7ffffd97, 1), + BPF_EXIT_INSN(), + BPF_MOV64_IMM(R2, 1), + BPF_ALU64_REG(BPF_LSH, R0, R2), + BPF_MOV32_IMM(R4, -1234), + BPF_JMP_REG(BPF_JEQ, R0, R4, 1), + BPF_EXIT_INSN(), + BPF_ALU64_IMM(BPF_AND, R4, 63), + BPF_ALU64_REG(BPF_LSH, R0, R4), /* R0 <= 46 */ + BPF_MOV64_IMM(R3, 47), + BPF_ALU64_REG(BPF_ARSH, R0, R3), + BPF_JMP_IMM(BPF_JEQ, R0, -617, 1), + BPF_EXIT_INSN(), + BPF_MOV64_IMM(R2, 1), + BPF_ALU64_REG(BPF_LSH, R4, R2), /* R4 = 46 << 1 */ + BPF_JMP_IMM(BPF_JEQ, R4, 92, 1), + BPF_EXIT_INSN(), + BPF_MOV64_IMM(R4, 4), + BPF_ALU64_REG(BPF_LSH, R4, R4), /* R4 = 4 << 4 */ + BPF_JMP_IMM(BPF_JEQ, R4, 64, 1), + BPF_EXIT_INSN(), + BPF_MOV64_IMM(R4, 5), + BPF_ALU32_REG(BPF_LSH, R4, R4), /* R4 = 5 << 5 */ + BPF_JMP_IMM(BPF_JEQ, R4, 160, 1), + BPF_EXIT_INSN(), + BPF_MOV64_IMM(R0, -1), + BPF_EXIT_INSN(), + }, + INTERNAL, + { }, + { { 0, -1 } } + }, + { "INT: DIV + ABS", .u.insns_int = { BPF_ALU64_REG(BPF_MOV, R6, R1), -- 1.7.9.5