From patchwork Fri Jan 28 23:45:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 12729299 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71E53C433F5 for ; Fri, 28 Jan 2022 23:51:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351870AbiA1Xvb convert rfc822-to-8bit (ORCPT ); Fri, 28 Jan 2022 18:51:31 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:39800 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351840AbiA1Xv3 (ORCPT ); Fri, 28 Jan 2022 18:51:29 -0500 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 20SKOkQJ018916 for ; Fri, 28 Jan 2022 15:51:29 -0800 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3dv8umee4f-10 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 28 Jan 2022 15:51:29 -0800 Received: from twshared11487.23.frc3.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:21d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Fri, 28 Jan 2022 15:51:27 -0800 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 559E628E032D4; Fri, 28 Jan 2022 15:45:44 -0800 (PST) From: Song Liu To: , , CC: , , , , , , , Song Liu Subject: [PATCH v7 bpf-next 9/9] bpf, x86_64: use bpf_jit_binary_pack_alloc Date: Fri, 28 Jan 2022 15:45:17 -0800 Message-ID: <20220128234517.3503701-10-song@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220128234517.3503701-1-song@kernel.org> References: <20220128234517.3503701-1-song@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: rkFEGe3bY4LStAgLsfuGGcEQdyN6_iTh X-Proofpoint-GUID: rkFEGe3bY4LStAgLsfuGGcEQdyN6_iTh X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2022-01-28_08,2022-01-28_01,2021-12-02_01 X-Proofpoint-Spam-Details: rule=fb_outbound_notspam policy=fb_outbound score=0 adultscore=0 mlxscore=0 spamscore=0 bulkscore=0 suspectscore=0 malwarescore=0 mlxlogscore=960 priorityscore=1501 impostorscore=0 lowpriorityscore=0 clxscore=1034 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2201280129 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Song Liu Use bpf_jit_binary_pack_alloc in x86_64 jit. The jit engine first writes the program to the rw buffer. When the jit is done, the program is copied to the final location with bpf_jit_binary_pack_finalize. Note that we need to do bpf_tail_call_direct_fixup after finalize. Therefore, the text_live = false logic in __bpf_arch_text_poke is no longer needed. Signed-off-by: Song Liu --- arch/x86/net/bpf_jit_comp.c | 59 +++++++++++++++++++------------------ 1 file changed, 31 insertions(+), 28 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 9792bf10d881..afb957e63e3d 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -330,8 +330,7 @@ static int emit_jump(u8 **pprog, void *func, void *ip) } static int __bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, - void *old_addr, void *new_addr, - const bool text_live) + void *old_addr, void *new_addr) { const u8 *nop_insn = x86_nops[5]; u8 old_insn[X86_PATCH_SIZE]; @@ -365,10 +364,7 @@ static int __bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, goto out; ret = 1; if (memcmp(ip, new_insn, X86_PATCH_SIZE)) { - if (text_live) - text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL); - else - memcpy(ip, new_insn, X86_PATCH_SIZE); + text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL); ret = 0; } out: @@ -384,7 +380,7 @@ int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, /* BPF poking in modules is not supported */ return -EINVAL; - return __bpf_arch_text_poke(ip, t, old_addr, new_addr, true); + return __bpf_arch_text_poke(ip, t, old_addr, new_addr); } #define EMIT_LFENCE() EMIT3(0x0F, 0xAE, 0xE8) @@ -558,24 +554,15 @@ static void bpf_tail_call_direct_fixup(struct bpf_prog *prog) mutex_lock(&array->aux->poke_mutex); target = array->ptrs[poke->tail_call.key]; if (target) { - /* Plain memcpy is used when image is not live yet - * and still not locked as read-only. Once poke - * location is active (poke->tailcall_target_stable), - * any parallel bpf_arch_text_poke() might occur - * still on the read-write image until we finally - * locked it as read-only. Both modifications on - * the given image are under text_mutex to avoid - * interference. - */ ret = __bpf_arch_text_poke(poke->tailcall_target, BPF_MOD_JUMP, NULL, (u8 *)target->bpf_func + - poke->adj_off, false); + poke->adj_off); BUG_ON(ret < 0); ret = __bpf_arch_text_poke(poke->tailcall_bypass, BPF_MOD_JUMP, (u8 *)poke->tailcall_target + - X86_PATCH_SIZE, NULL, false); + X86_PATCH_SIZE, NULL); BUG_ON(ret < 0); } WRITE_ONCE(poke->tailcall_target_stable, true); @@ -867,7 +854,7 @@ static void emit_nops(u8 **pprog, int len) #define INSN_SZ_DIFF (((addrs[i] - addrs[i - 1]) - (prog - temp))) -static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, +static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image, int oldproglen, struct jit_context *ctx, bool jmp_padding) { bool tail_call_reachable = bpf_prog->aux->tail_call_reachable; @@ -894,8 +881,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, push_callee_regs(&prog, callee_regs_used); ilen = prog - temp; - if (image) - memcpy(image + proglen, temp, ilen); + if (rw_image) + memcpy(rw_image + proglen, temp, ilen); proglen += ilen; addrs[0] = proglen; prog = temp; @@ -1324,8 +1311,10 @@ st: if (is_imm8(insn->off)) pr_err("extable->insn doesn't fit into 32-bit\n"); return -EFAULT; } - ex->insn = delta; + /* switch ex to rw buffer for writes */ + ex = (void *)rw_image + ((void *)ex - (void *)image); + ex->insn = delta; ex->type = EX_TYPE_BPF; if (dst_reg > BPF_REG_9) { @@ -1706,7 +1695,7 @@ st: if (is_imm8(insn->off)) pr_err("bpf_jit: fatal error\n"); return -EFAULT; } - memcpy(image + proglen, temp, ilen); + memcpy(rw_image + proglen, temp, ilen); } proglen += ilen; addrs[i] = proglen; @@ -2247,6 +2236,7 @@ int arch_prepare_bpf_dispatcher(void *image, s64 *funcs, int num_funcs) } struct x64_jit_data { + struct bpf_binary_header *rw_header; struct bpf_binary_header *header; int *addrs; u8 *image; @@ -2259,6 +2249,7 @@ struct x64_jit_data { struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) { + struct bpf_binary_header *rw_header = NULL; struct bpf_binary_header *header = NULL; struct bpf_prog *tmp, *orig_prog = prog; struct x64_jit_data *jit_data; @@ -2267,6 +2258,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) bool tmp_blinded = false; bool extra_pass = false; bool padding = false; + u8 *rw_image = NULL; u8 *image = NULL; int *addrs; int pass; @@ -2302,6 +2294,8 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) oldproglen = jit_data->proglen; image = jit_data->image; header = jit_data->header; + rw_header = jit_data->rw_header; + rw_image = (void *)rw_header + ((void *)image - (void *)header); extra_pass = true; padding = true; goto skip_init_addrs; @@ -2332,12 +2326,12 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) for (pass = 0; pass < MAX_PASSES || image; pass++) { if (!padding && pass >= PADDING_PASSES) padding = true; - proglen = do_jit(prog, addrs, image, oldproglen, &ctx, padding); + proglen = do_jit(prog, addrs, image, rw_image, oldproglen, &ctx, padding); if (proglen <= 0) { out_image: image = NULL; if (header) - bpf_jit_binary_free(header); + bpf_jit_binary_pack_free(header, rw_header); prog = orig_prog; goto out_addrs; } @@ -2361,8 +2355,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) sizeof(struct exception_table_entry); /* allocate module memory for x86 insns and extable */ - header = bpf_jit_binary_alloc(roundup(proglen, align) + extable_size, - &image, align, jit_fill_hole); + header = bpf_jit_binary_pack_alloc(roundup(proglen, align) + extable_size, + &image, align, &rw_header, &rw_image, + jit_fill_hole); if (!header) { prog = orig_prog; goto out_addrs; @@ -2378,14 +2373,22 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) if (image) { if (!prog->is_func || extra_pass) { + /* + * bpf_jit_binary_pack_finalize fails in two scenarios: + * 1) header is not pointing to proper module memory; + * 2) the arch doesn't support bpf_arch_text_copy(). + * + * Both cases are serious bugs that we should not continue. + */ + BUG_ON(bpf_jit_binary_pack_finalize(prog, header, rw_header)); bpf_tail_call_direct_fixup(prog); - bpf_jit_binary_lock_ro(header); } else { jit_data->addrs = addrs; jit_data->ctx = ctx; jit_data->proglen = proglen; jit_data->image = image; jit_data->header = header; + jit_data->rw_header = rw_header; } prog->bpf_func = (void *)image; prog->jited = 1;