From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 180C1C43381 for ; Mon, 25 Feb 2019 21:28:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DAF3321734 for ; Mon, 25 Feb 2019 21:28:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551130117; bh=FRBkAyEGXQd8zE350xzeCZYOsP/7sQUcZqCfov/qF0c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UvMIgPQ72vsWyWJJSLDp5dzxbDg0z6QcPJ8hizRUsAR3f5UinRXyIj3N4P5Z8PXVP XiplA4PKcEYe0OcbS6kJEp5AgKxwyg58F/4KckhzZ1MCyW7wTiSDB2G6w+jdTeYu9+ MSwbkZp/xtE1ELhSQrITBFDIgIrouIzXSl774m/o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731871AbfBYV2f (ORCPT ); Mon, 25 Feb 2019 16:28:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:34364 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731865AbfBYV2e (ORCPT ); Mon, 25 Feb 2019 16:28:34 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3C38F20C01; Mon, 25 Feb 2019 21:28:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551130113; bh=FRBkAyEGXQd8zE350xzeCZYOsP/7sQUcZqCfov/qF0c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dx9maqFYevyCkQd2g10RKgdjNgMXmYZFc3qAsupPLQLoon8d6OtXJcpdbTqmVjqJI 9942F/pw6WVCSlUEoxna2j5xoP4Mb/nSzz2oNODPiDxPr9nfpucG39N+dxZIn73gXf JYxcY1eOFXBBuBTTUsbFxgY0N3IQRcloNYEs4aGA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paul Burton , Daniel Borkmann Subject: [PATCH 4.20 004/183] MIPS: eBPF: Always return sign extended 32b values Date: Mon, 25 Feb 2019 22:09:37 +0100 Message-Id: <20190225195055.405011105@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190225195054.748060397@linuxfoundation.org> References: <20190225195054.748060397@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Burton commit 13443154f6cac61d148471ede6d7f1f6b5ea946a upstream. The function prototype used to call JITed eBPF code (ie. the type of the struct bpf_prog bpf_func field) returns an unsigned int. The MIPS n64 ABI that MIPS64 kernels target defines that 32 bit integers should always be sign extended when passed in registers as either arguments or return values. This means that when returning any value which may not already be sign extended (ie. of type REG_64BIT or REG_32BIT_ZERO_EX) we need to perform that sign extension in order to comply with the n64 ABI. Without this we see strange looking test failures from test_bpf.ko, such as: test_bpf: #65 ALU64_MOV_X: dst = 4294967295 jited:1 ret -1 != -1 FAIL (1 times) Although the return value printed matches the expected value, this is only because printf is only examining the least significant 32 bits of the 64 bit register value we returned. The register holding the expected value is sign extended whilst the v0 register was set to a zero extended value by our JITed code, so when compared by a conditional branch instruction the values are not equal. We already handle this when the return value register is of type REG_32BIT_ZERO_EX, so simply extend this to also cover REG_64BIT. Signed-off-by: Paul Burton Fixes: b6bd53f9c4e8 ("MIPS: Add missing file for eBPF JIT.") Cc: stable@vger.kernel.org # v4.13+ Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman --- arch/mips/net/ebpf_jit.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/arch/mips/net/ebpf_jit.c +++ b/arch/mips/net/ebpf_jit.c @@ -343,12 +343,15 @@ static int build_int_epilogue(struct jit const struct bpf_prog *prog = ctx->skf; int stack_adjust = ctx->stack_size; int store_offset = stack_adjust - 8; + enum reg_val_type td; int r0 = MIPS_R_V0; - if (dest_reg == MIPS_R_RA && - get_reg_val_type(ctx, prog->len, BPF_REG_0) == REG_32BIT_ZERO_EX) + if (dest_reg == MIPS_R_RA) { /* Don't let zero extended value escape. */ - emit_instr(ctx, sll, r0, r0, 0); + td = get_reg_val_type(ctx, prog->len, BPF_REG_0); + if (td == REG_64BIT || td == REG_32BIT_ZERO_EX) + emit_instr(ctx, sll, r0, r0, 0); + } if (ctx->flags & EBPF_SAVE_RA) { emit_instr(ctx, ld, MIPS_R_RA, store_offset, MIPS_R_SP);