From patchwork Tue Sep 26 19:00:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 13399596 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6FB8D3B7B0 for ; Tue, 26 Sep 2023 19:00:45 +0000 (UTC) Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE6DF199 for ; Tue, 26 Sep 2023 12:00:43 -0700 (PDT) Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.17.1.19/8.17.1.19) with ESMTP id 38QIgQJ9018173 for ; Tue, 26 Sep 2023 12:00:43 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by m0001303.ppops.net (PPS) with ESMTPS id 3tc4r2r7bq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 26 Sep 2023 12:00:42 -0700 Received: from twshared7604.38.frc1.facebook.com (2620:10d:c0a8:1c::1b) by mail.thefacebook.com (2620:10d:c0a8:82::b) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Tue, 26 Sep 2023 12:00:40 -0700 Received: by devbig932.frc1.facebook.com (Postfix, from userid 4523) id 214C9250068B9; Tue, 26 Sep 2023 12:00:31 -0700 (PDT) From: Song Liu To: CC: , , , , , , , Song Liu Subject: [PATCH v3 bpf-next 5/8] bpf, x86: Adjust arch_prepare_bpf_trampoline return value Date: Tue, 26 Sep 2023 12:00:17 -0700 Message-ID: <20230926190020.1111575-6-song@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230926190020.1111575-1-song@kernel.org> References: <20230926190020.1111575-1-song@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: VjmW6RsgTB0hBjChFHdEHS9pRcQ91CKi X-Proofpoint-ORIG-GUID: VjmW6RsgTB0hBjChFHdEHS9pRcQ91CKi X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-09-26_13,2023-09-26_01,2023-05-22_02 X-Spam-Status: No, score=-1.6 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net x86's implementation of arch_prepare_bpf_trampoline() requires BPF_INSN_SAFETY buffer space between end of program and image_end. OTOH, the return value does not include BPF_INSN_SAFETY. This doesn't cause any real issue at the moment. However, "image" of size retval is not enough for arch_prepare_bpf_trampoline(). This will cause confusion when we introduce a new helper arch_bpf_trampoline_size(). To avoid future confusion, adjust the return value to include BPF_INSN_SAFETY. Signed-off-by: Song Liu Acked-by: Ilya Leoshkevich --- arch/x86/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 8c10d9abc239..5f7528cac344 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -2671,7 +2671,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i ret = -EFAULT; goto cleanup; } - ret = prog - (u8 *)image; + ret = prog - (u8 *)image + BPF_INSN_SAFETY; cleanup: kfree(branches);