Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946155AbbFSVTc (ORCPT ); Fri, 19 Jun 2015 17:19:32 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51679 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756061AbbFSUjF (ORCPT ); Fri, 19 Jun 2015 16:39:05 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexei Starovoitov , "David S. Miller" Subject: [PATCH 4.0 004/105] x86: bpf_jit: fix FROM_BE16 and FROM_LE16/32 instructions Date: Fri, 19 Jun 2015 13:34:54 -0700 Message-Id: <20150619203558.334562748@linuxfoundation.org> X-Mailer: git-send-email 2.4.4 In-Reply-To: <20150619203558.187802739@linuxfoundation.org> References: <20150619203558.187802739@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2063 Lines: 75 4.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexei Starovoitov [ Upstream commit 343f845b375989f1753f605902931fa939aa2223 ] FROM_BE16: 'ror %reg, 8' doesn't clear upper bits of the register, so use additional 'movzwl' insn to zero extend 16 bits into 64 FROM_LE16: should zero extend lower 16 bits into 64 bit FROM_LE32: should zero extend lower 32 bits into 64 bit Fixes: 89aa075832b0 ("net: sock: allow eBPF programs to be attached to sockets") Signed-off-by: Alexei Starovoitov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- arch/x86/net/bpf_jit_comp.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -559,6 +559,13 @@ static int do_jit(struct bpf_prog *bpf_p if (is_ereg(dst_reg)) EMIT1(0x41); EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8); + + /* emit 'movzwl eax, ax' */ + if (is_ereg(dst_reg)) + EMIT3(0x45, 0x0F, 0xB7); + else + EMIT2(0x0F, 0xB7); + EMIT1(add_2reg(0xC0, dst_reg, dst_reg)); break; case 32: /* emit 'bswap eax' to swap lower 4 bytes */ @@ -577,6 +584,27 @@ static int do_jit(struct bpf_prog *bpf_p break; case BPF_ALU | BPF_END | BPF_FROM_LE: + switch (imm32) { + case 16: + /* emit 'movzwl eax, ax' to zero extend 16-bit + * into 64 bit + */ + if (is_ereg(dst_reg)) + EMIT3(0x45, 0x0F, 0xB7); + else + EMIT2(0x0F, 0xB7); + EMIT1(add_2reg(0xC0, dst_reg, dst_reg)); + break; + case 32: + /* emit 'mov eax, eax' to clear upper 32-bits */ + if (is_ereg(dst_reg)) + EMIT1(0x45); + EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg)); + break; + case 64: + /* nop */ + break; + } break; /* ST: *(u8*)(dst_reg + off) = imm */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/