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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 B99FDC47409 for ; Fri, 27 Dec 2019 17:49:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 98058206CB for ; Fri, 27 Dec 2019 17:49:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577468948; bh=YgJ1Rj9xwayAqRHWe+d8iXp2E6DpWtapNBQW+ENO0ok=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0Mzx9ODtITZ1xmR/h5uv1CrZTD4DfzZSaZQCMYWezdWHs9ZW+lrICfOkTN786ZPLe Zy6hp5wcemZRfSGgaIZQFApImi9MS5kwqwVQxfdhUvF1D11bgP8cemMxCpm9OmbHMe /6HRub5TsOH7pejGQlkoVCLBYj5bhe75NrknKVO4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727666AbfL0RtH (ORCPT ); Fri, 27 Dec 2019 12:49:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:42822 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727612AbfL0Rof (ORCPT ); Fri, 27 Dec 2019 12:44:35 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B961722522; Fri, 27 Dec 2019 17:44:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577468674; bh=YgJ1Rj9xwayAqRHWe+d8iXp2E6DpWtapNBQW+ENO0ok=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KjtNQ0xFmWGUiaXa15XJvFLbxnB6XjejKN8/f7mpv8GqMN+U/wVfioD5zH1FRWDJi p5EN8vwnOP3gMuumb6tpMgnu3FI03R538GIyTd2fyoKdOBCLHsEDrLjNV1zInTsNjW i2mKC8jkmchHtrLbb+AcIJTt3MWGmDJ0j4Csufww= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Paul Chaignon , Mahshid Khezri , Daniel Borkmann , Martin KaFai Lau , Sasha Levin , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-mips@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 34/84] bpf, mips: Limit to 33 tail calls Date: Fri, 27 Dec 2019 12:43:02 -0500 Message-Id: <20191227174352.6264-34-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191227174352.6264-1-sashal@kernel.org> References: <20191227174352.6264-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: Paul Chaignon [ Upstream commit e49e6f6db04e915dccb494ae10fa14888fea6f89 ] All BPF JIT compilers except RISC-V's and MIPS' enforce a 33-tail calls limit at runtime. In addition, a test was recently added, in tailcalls2, to check this limit. This patch updates the tail call limit in MIPS' JIT compiler to allow 33 tail calls. Fixes: b6bd53f9c4e8 ("MIPS: Add missing file for eBPF JIT.") Reported-by: Mahshid Khezri Signed-off-by: Paul Chaignon Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/b8eb2caac1c25453c539248e56ca22f74b5316af.1575916815.git.paul.chaignon@gmail.com Signed-off-by: Sasha Levin --- arch/mips/net/ebpf_jit.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c index 9bda82ed75eb..3832c4628608 100644 --- a/arch/mips/net/ebpf_jit.c +++ b/arch/mips/net/ebpf_jit.c @@ -586,6 +586,7 @@ static void emit_const_to_reg(struct jit_ctx *ctx, int dst, u64 value) static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx) { int off, b_off; + int tcc_reg; ctx->flags |= EBPF_SEEN_TC; /* @@ -598,14 +599,14 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx) b_off = b_imm(this_idx + 1, ctx); emit_instr(ctx, bne, MIPS_R_AT, MIPS_R_ZERO, b_off); /* - * if (--TCC < 0) + * if (TCC-- < 0) * goto out; */ /* Delay slot */ - emit_instr(ctx, daddiu, MIPS_R_T5, - (ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4, -1); + tcc_reg = (ctx->flags & EBPF_TCC_IN_V1) ? MIPS_R_V1 : MIPS_R_S4; + emit_instr(ctx, daddiu, MIPS_R_T5, tcc_reg, -1); b_off = b_imm(this_idx + 1, ctx); - emit_instr(ctx, bltz, MIPS_R_T5, b_off); + emit_instr(ctx, bltz, tcc_reg, b_off); /* * prog = array->ptrs[index]; * if (prog == NULL) -- 2.20.1