From patchwork Mon Aug 8 04:07:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xu Kuohai X-Patchwork-Id: 12938463 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 65477C00140 for ; Mon, 8 Aug 2022 03:58:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232650AbiHHD6n (ORCPT ); Sun, 7 Aug 2022 23:58:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230364AbiHHD6m (ORCPT ); Sun, 7 Aug 2022 23:58:42 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FA7610FC9; Sun, 7 Aug 2022 20:58:40 -0700 (PDT) Received: from kwepemi500013.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4M1Mmd5CM1zjX6Y; Mon, 8 Aug 2022 11:55:29 +0800 (CST) Received: from huawei.com (10.67.174.197) by kwepemi500013.china.huawei.com (7.221.188.120) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 8 Aug 2022 11:58:38 +0800 From: Xu Kuohai To: , , CC: , Daniel Borkmann , Jean-Philippe Brucker Subject: [PATCH bpf] bpf, arm64: Fix bpf trampoline instruction endianness Date: Mon, 8 Aug 2022 00:07:35 -0400 Message-ID: <20220808040735.1232002-1-xukuohai@huawei.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Originating-IP: [10.67.174.197] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemi500013.china.huawei.com (7.221.188.120) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net The sparse tool complains as follows: arch/arm64/net/bpf_jit_comp.c:1684:16: warning: incorrect type in assignment (different base types) arch/arm64/net/bpf_jit_comp.c:1684:16: expected unsigned int [usertype] *branch arch/arm64/net/bpf_jit_comp.c:1684:16: got restricted __le32 [usertype] * arch/arm64/net/bpf_jit_comp.c:1700:52: error: subtraction of different types can't work (different base types) arch/arm64/net/bpf_jit_comp.c:1734:29: warning: incorrect type in assignment (different base types) arch/arm64/net/bpf_jit_comp.c:1734:29: expected unsigned int [usertype] * arch/arm64/net/bpf_jit_comp.c:1734:29: got restricted __le32 [usertype] * arch/arm64/net/bpf_jit_comp.c:1918:52: error: subtraction of different types can't work (different base types) This is because the variable branch in function invoke_bpf_prog and the variable branches in function prepare_trampoline are defined as type u32 *, which conflicts with ctx->image's type __le32 *, so sparse complains when assignment or arithmetic operation are performed on these two variables and ctx->image. Since arm64 instructions are always little-endian, change the type of these two variables to __le32 * and call cpu_to_le32 to convert instruction to little-endian before writing it to memory. Reported-by: kernel test robot Fixes: efc9909fdce0 ("bpf, arm64: Add bpf trampoline for arm64") Signed-off-by: Xu Kuohai Reviewed-by: Jean-Philippe Brucker --- arch/arm64/net/bpf_jit_comp.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 7ca8779ae34f..29dc55da2476 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1643,7 +1643,7 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l, int args_off, int retval_off, int run_ctx_off, bool save_ret) { - u32 *branch; + __le32 *branch; u64 enter_prog; u64 exit_prog; struct bpf_prog *p = l->link.prog; @@ -1698,7 +1698,7 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l, if (ctx->image) { int offset = &ctx->image[ctx->idx] - branch; - *branch = A64_CBZ(1, A64_R(0), offset); + *branch = cpu_to_le32(A64_CBZ(1, A64_R(0), offset)); } /* arg1: prog */ @@ -1713,7 +1713,7 @@ static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l, static void invoke_bpf_mod_ret(struct jit_ctx *ctx, struct bpf_tramp_links *tl, int args_off, int retval_off, int run_ctx_off, - u32 **branches) + __le32 **branches) { int i; @@ -1784,7 +1784,7 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im, struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT]; struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN]; bool save_ret; - u32 **branches = NULL; + __le32 **branches = NULL; /* trampoline stack layout: * [ parent ip ] @@ -1892,7 +1892,7 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im, flags & BPF_TRAMP_F_RET_FENTRY_RET); if (fmod_ret->nr_links) { - branches = kcalloc(fmod_ret->nr_links, sizeof(u32 *), + branches = kcalloc(fmod_ret->nr_links, sizeof(__le32 *), GFP_KERNEL); if (!branches) return -ENOMEM; @@ -1916,7 +1916,7 @@ static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im, /* update the branches saved in invoke_bpf_mod_ret with cbnz */ for (i = 0; i < fmod_ret->nr_links && ctx->image != NULL; i++) { int offset = &ctx->image[ctx->idx] - branches[i]; - *branches[i] = A64_CBNZ(1, A64_R(10), offset); + *branches[i] = cpu_to_le32(A64_CBNZ(1, A64_R(10), offset)); } for (i = 0; i < fexit->nr_links; i++)