From nobody Tue Dec 16 07:34:27 2025 Received: from mail-wm1-f45.google.com (mail-wm1-f45.google.com [209.85.128.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 314C822B8DB for ; Tue, 20 May 2025 13:01:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.45 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747746104; cv=none; b=VoUbaSW5/Roc1uOSI1fDZlWYxvHAtATCeYUhR+1CwVo8ktMUh7OA4rFM/EsNKB29RX/1mpo2O7DEcSyqNYpW6TDtUbTK19oQOOye4lYNS/dWwIIQ1aQKiwYSnExkaVjP2xt7eWoN74HXBnqHtUhPiGv1dEcKbxrzGbOQXWcllRA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747746104; c=relaxed/simple; bh=c4jojo3FrsibvRNue34ztcliWE7ZrRLcrwLqEcNS708=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=I9Cp9uJBs2cRGLR4Kp8F4Wmv9bofbDBu9Soi+IYjr8tchPhcCERnAfytSfFNgbC7avzncRDJgxbM2PkFoSc9MYsFAAtJKWCqsPex5MYMfxssXYmcYXRmR/4tMr2RRVyIlFpAPaQxLKJTvK6NEQOo661AbTh0vcWiBMGK4oMwhtA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=isovalent.com; spf=pass smtp.mailfrom=isovalent.com; dkim=pass (2048-bit key) header.d=isovalent.com header.i=@isovalent.com header.b=PP5wTbRV; arc=none smtp.client-ip=209.85.128.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=isovalent.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=isovalent.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=isovalent.com header.i=@isovalent.com header.b="PP5wTbRV" Received: by mail-wm1-f45.google.com with SMTP id 5b1f17b1804b1-43cfe63c592so61750665e9.2 for ; Tue, 20 May 2025 06:01:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isovalent.com; s=google; t=1747746100; x=1748350900; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=eaoULxe21siuTC/4/X/NX4W28Unf1olYgXifLjKBGNc=; b=PP5wTbRV9rRTA1QvHhjX0QxlTMTp/P9GZYS6XNW0+7/UXLaba/GVxXixj4+P2NsvV/ Nxy8l7DRPnL4ITY8enPl+YyKx7kd7gprpImz6QSsCrxWtp2Cd1lWZJLqS4L7+ARyiX/h ro69QgHxYAdCk+XGoMC1ousMGaHAmwr4+ZXM/XGZ+ncJGmBMu5Cbilf3fJoGGnwWTFRW 3hWQ0slsrindc3KPAssdwBfWKSDgL+SvcTmjcQXCnfCFsHonVFtBNjF/8eMJwA78lUw+ h18+HK2XOtj9rdPHddEWkYznZzupqcS/TbN9ScuJJohwxcIG3bRNvdX36zRUxZ/xNW6L kC/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747746100; x=1748350900; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=eaoULxe21siuTC/4/X/NX4W28Unf1olYgXifLjKBGNc=; b=NWz0jJ9rsGlHss4h0W2J8P3EvY1Z38JmaKIG+aPGHufybqgZoMJWMmcM6tUW3oEDHb Y1rUVb7AqJfk8l/jYPO+3MO9/99RCx8MusDEfoD19UWp8i1RQiBZnC3BUKE5gOkjl90/ nnh8QCRmZK7+qr1gaTaR5rSa0raRBN26FAQcDeBWoqhjoYhFlsNieypa8IZ7ulhbasCI Ai98xZKv5vpze0cMDm+2iWJm1jOIulXsBv9A/TPLD8D5de8gOmuynlmjzgzxQovfrgwN CYN4C3ECJEpCddbHP0fUPJByj/lgfmY2doSgXBWBPhJxWpLBRBxiTvNOO8jazJVAowmu VqAg== X-Forwarded-Encrypted: i=1; AJvYcCUZ2ckhY2Q0RYUOajas1xFCgTxBqqIVISJHkQj+OMjFZvUwMTT+OEOgkemGq2KTtYXF4DWQbuOOuCM7WYY=@vger.kernel.org X-Gm-Message-State: AOJu0Yy13iMuK7pPTIqEe6CIZWEZaUei8ORx1fJRqf8lIav90Ja5ARw1 uQbKo4go14cv2/IdQzRtVxKYViUK2JZLiEEhk0PQJr39AekbH2fIEtQZSo6BN2dVtIA= X-Gm-Gg: ASbGnctHUNkUAWj5RR/DO0Qsy/unH59EGys1llTReph4+t37sFmHpw9eYCKXLVSORJH Yby3uDKUnNdKubZZ1seeHs2GJKYmdHSO8RtG8RXgZ/pPeqF6awdcCjidCTaImzgxlLDFA2kXJTr nljspyFd+M4E8X0MqEEGRDREUFWd7Qb5cSmUP1Z88gHqJkNrlR91sbKSAaZx3QI5f26oBhweUrP 6b26qeP8hA1/bpsig5lCW7dJMLBmwlKpztKDdAMP2SDrOm2pXAK6yAQhC1K4MwwoTwJZsfUl48I E5EnBjFvJsUpsc+jord3UusYetkUTBFO8Dn9eLSO07PcKVFtOAP8UK4mDL5zGSVClxyzs/hIxu8 2KtH2cjOZgVB/ZeYqJ25FzKhpPvBWIW3V5iR3dZQ3fqYlws8= X-Google-Smtp-Source: AGHT+IG0fsLJi/NVZ1/ziNxrgyZD18gc4dqp0HpWd7a9P0r35DxhIE6icjrA9lZempr35X+kXG5pyA== X-Received: by 2002:a05:600c:34d4:b0:442:e0e0:250 with SMTP id 5b1f17b1804b1-442fd67200emr153675135e9.29.1747746100077; Tue, 20 May 2025 06:01:40 -0700 (PDT) Received: from [192.168.1.240] (0.0.6.0.0.0.0.0.0.0.0.0.0.0.0.0.f.f.6.2.a.5.a.7.0.b.8.0.1.0.0.2.ip6.arpa. [2001:8b0:7a5a:26ff::600]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a35ca5a8cfsm16538095f8f.37.2025.05.20.06.01.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 May 2025 06:01:39 -0700 (PDT) From: Lorenz Bauer Date: Tue, 20 May 2025 14:01:17 +0100 Subject: [PATCH bpf-next v5 1/3] btf: allow mmap of vmlinux btf Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250520-vmlinux-mmap-v5-1-e8c941acc414@isovalent.com> References: <20250520-vmlinux-mmap-v5-0-e8c941acc414@isovalent.com> In-Reply-To: <20250520-vmlinux-mmap-v5-0-e8c941acc414@isovalent.com> To: Arnd Bergmann , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Lorenz Bauer , Alan Maguire X-Mailer: b4 0.14.2 User space needs access to kernel BTF for many modern features of BPF. Right now each process needs to read the BTF blob either in pieces or as a whole. Allow mmaping the sysfs file so that processes can directly access the memory allocated for it in the kernel. remap_pfn_range is used instead of vm_insert_page due to aarch64 compatibility issues. Tested-by: Alan Maguire Signed-off-by: Lorenz Bauer Reviewed-by: Shakeel Butt --- include/asm-generic/vmlinux.lds.h | 3 ++- kernel/bpf/sysfs_btf.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 34 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinu= x.lds.h index 58a635a6d5bdf0c53c267c2a3d21a5ed8678ce73..1750390735fac7637cc4d2fa05f= 96cb2a36aa448 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -667,10 +667,11 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPE= LLER_CLANG) */ #ifdef CONFIG_DEBUG_INFO_BTF #define BTF \ + . =3D ALIGN(PAGE_SIZE); \ .BTF : AT(ADDR(.BTF) - LOAD_OFFSET) { \ BOUNDED_SECTION_BY(.BTF, _BTF) \ } \ - . =3D ALIGN(4); \ + . =3D ALIGN(PAGE_SIZE); \ .BTF_ids : AT(ADDR(.BTF_ids) - LOAD_OFFSET) { \ *(.BTF_ids) \ } diff --git a/kernel/bpf/sysfs_btf.c b/kernel/bpf/sysfs_btf.c index 81d6cf90584a7157929c50f62a5c6862e7a3d081..941d0d2427e3a2d27e8f1cff7b6= 424d0d41817c1 100644 --- a/kernel/bpf/sysfs_btf.c +++ b/kernel/bpf/sysfs_btf.c @@ -7,14 +7,46 @@ #include #include #include +#include +#include +#include =20 /* See scripts/link-vmlinux.sh, gen_btf() func for details */ extern char __start_BTF[]; extern char __stop_BTF[]; =20 +static int btf_sysfs_vmlinux_mmap(struct file *filp, struct kobject *kobj, + const struct bin_attribute *attr, + struct vm_area_struct *vma) +{ + unsigned long pages =3D PAGE_ALIGN(attr->size) >> PAGE_SHIFT; + size_t vm_size =3D vma->vm_end - vma->vm_start; + phys_addr_t addr =3D virt_to_phys(__start_BTF); + unsigned long pfn =3D addr >> PAGE_SHIFT; + + if (attr->private !=3D __start_BTF || !PAGE_ALIGNED(addr)) + return -EINVAL; + + if (vma->vm_pgoff) + return -EINVAL; + + if (vma->vm_flags & (VM_WRITE | VM_EXEC | VM_MAYSHARE)) + return -EACCES; + + if (pfn + pages < pfn) + return -EINVAL; + + if ((vm_size >> PAGE_SHIFT) > pages) + return -EINVAL; + + vm_flags_mod(vma, VM_DONTDUMP, VM_MAYEXEC | VM_MAYWRITE); + return remap_pfn_range(vma, vma->vm_start, pfn, vm_size, vma->vm_page_pro= t); +} + static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init =3D { .attr =3D { .name =3D "vmlinux", .mode =3D 0444, }, .read_new =3D sysfs_bin_attr_simple_read, + .mmap =3D btf_sysfs_vmlinux_mmap, }; =20 struct kobject *btf_kobj; --=20 2.49.0 From nobody Tue Dec 16 07:34:27 2025 Received: from mail-wm1-f48.google.com (mail-wm1-f48.google.com [209.85.128.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7B97D22B8D4 for ; Tue, 20 May 2025 13:01:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.48 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747746106; cv=none; b=oAjVvPwh+4zTU3Z60ySZ04LENfCFgd+LUPYBBSlKlo/eQH0GZtdTJIaCrsopNstViuqu5SEPkd4qXC6pyn5++H/J0qb8YzzlWXJzQTFxbj8cWtz8A6wyOVfKnRJBRr5VVmlE8b21aeK6GUOGGyedAsxXjOeKYrIO5lah9eoTqz4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747746106; c=relaxed/simple; bh=onxYhud+KbP9G92KrrkVXhWhrAZjMw6PhcWJrcxgw9g=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=lI6bKIQywOh5ZcThSStcEaZph4ytU/KBEsB5hMFSBaT1LtCr8A+9y4HBI3/R8xzc6IXzjI3oQl+HxuaH3oKoqTXvqFYBwE5dI6lJT3HBuBKQQwNtkGrtP7p0l7dhsYnMa8eA/ENw9alYhJfSNZz1apLmI2wstQnLQIk37jQi/c4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=isovalent.com; spf=pass smtp.mailfrom=isovalent.com; dkim=pass (2048-bit key) header.d=isovalent.com header.i=@isovalent.com header.b=WdcEY+pt; arc=none smtp.client-ip=209.85.128.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=isovalent.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=isovalent.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=isovalent.com header.i=@isovalent.com header.b="WdcEY+pt" Received: by mail-wm1-f48.google.com with SMTP id 5b1f17b1804b1-43cf680d351so39549115e9.0 for ; Tue, 20 May 2025 06:01:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isovalent.com; s=google; t=1747746102; x=1748350902; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=OLk5G4Cel/wWxbE0AJcynDwZLLJtlvvXRoNS6jKTq6M=; b=WdcEY+pt4w0MfM0DuCLDEk0pdk8ZtsWlU+dYfUHpPY0R64urNJ+Jn+4izTxIb9V8D1 6WSc47jK1IzN4+S5pFL2nlXaIaje39BYGKZygYPXo+hJiKJOUpdKcolX9FB0D1SuWcig KG6Vn6N3wSSXj/IfhXiQFloqx8VSqzxiLsqi8mXNojtgU0lDahICt/+tXzlexKysapR4 SQRMRupfrKoepgAo8w2VFSOqlFeLzmFCZKdtSdceqcuaUEnarwi3I56Qw4Ob0qKYCS4j /AC0tNJVJI0DVGDdgwewiX1nU59j1p1qxieokBPx1Kfb2h+dF9DG6Af3J/F54tAxtvFa a/cw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747746102; x=1748350902; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=OLk5G4Cel/wWxbE0AJcynDwZLLJtlvvXRoNS6jKTq6M=; b=l57ik9cWyHXLrWLP631uR2XF+iFQ6AZd1M/5I1VTuws8D7ow17vJQnggq5NNYSy/k+ yZvNq2iP7TgekimVpCDw9eTt5OR3TsWLvdA8ae48AtDuOSu+8tUa4tBS375VS0sw51B4 XmVeqooALRBUBiLYF0/QKO2Ms3kLp8WjcYkd4asEKkC/wiRzBoMlC9XDoQCzVwmL7e81 1ir1IBOps7KrxHW1oPXakAPw2EVXJd9L6ceEh5Z16kEASYy57Jqz/AMXI5sIMimHTDg/ e9xv9lAfS//tKm8PtWmZiM+zWjmMr1WQget27sLgjIe7+gul7I/qf5C9Tq+1qZ1yYxOL jSpQ== X-Forwarded-Encrypted: i=1; AJvYcCW+CHntNAlSj0D8gwZM5SU0GGAkic/qRwqNr8S7SNPB7x5k6lyOxTqv5U1X1/VHRfZ59rnIWl9RV1O02pk=@vger.kernel.org X-Gm-Message-State: AOJu0YyuTtHpadQwHilAvxveOXmCiWYCFMYSAql7Yn2M+wHs3G6qNUTp FG0pgWeM3nRaFQgPD9l5xmAIGIsi+7OAcs0hMFTIsW8n5i0Ed7oPJsqc8A7kZMQhRMs= X-Gm-Gg: ASbGncuIRUAg33nM+lKcJTDqpWX7k9RrIbQBZCqCuYStF6zU5NcCVd3q3x34JGIDXM3 8QD3QhhjiyuI+SwWqeNtvMVzXZ1PzO3pCjgDULdNPw1607uBacscf1epZo3RD4tBynTSfMexIYN CyoS8qdZBIA93GXai18jrjiXU4ccg6FFWBQo6xJyXXstoUmMCgJRrFY55OD6xG+6lJnrcE/KtBo Y6MpZHhD4vIsexzSy122WVZ2r3flLZfuwY1ydrPAYbgizi6BQss2uycB0MlZqlPcs7zdN/zErKR +Xt/1BUVoSUPqHm1H/CSnJGac1tove6othXqtX4DPXpe1KnGsInemuIX6CRA1FBOFP+PPJIiWtE jI92I27ydWK5qyYTc1XgCXFS0sPJkfzKh2f5utMmyPutlAYU= X-Google-Smtp-Source: AGHT+IF+zmD+H27RSz/G+4dMOqhg+dz+ihe+221W/uu8LbDrI30vQwAeUCggEu1LDpdjLTvtZ+WKVw== X-Received: by 2002:a05:600c:5295:b0:43c:f3e1:a729 with SMTP id 5b1f17b1804b1-442f8514e9emr189410795e9.12.1747746101310; Tue, 20 May 2025 06:01:41 -0700 (PDT) Received: from [192.168.1.240] (0.0.6.0.0.0.0.0.0.0.0.0.0.0.0.0.f.f.6.2.a.5.a.7.0.b.8.0.1.0.0.2.ip6.arpa. [2001:8b0:7a5a:26ff::600]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a35ca5a8cfsm16538095f8f.37.2025.05.20.06.01.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 May 2025 06:01:40 -0700 (PDT) From: Lorenz Bauer Date: Tue, 20 May 2025 14:01:18 +0100 Subject: [PATCH bpf-next v5 2/3] selftests: bpf: add a test for mmapable vmlinux BTF Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250520-vmlinux-mmap-v5-2-e8c941acc414@isovalent.com> References: <20250520-vmlinux-mmap-v5-0-e8c941acc414@isovalent.com> In-Reply-To: <20250520-vmlinux-mmap-v5-0-e8c941acc414@isovalent.com> To: Arnd Bergmann , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Lorenz Bauer , Alan Maguire X-Mailer: b4 0.14.2 Add a basic test for the ability to mmap /sys/kernel/btf/vmlinux. Ensure that the data is valid BTF and that it is padded with zero. Tested-by: Alan Maguire Signed-off-by: Lorenz Bauer --- tools/testing/selftests/bpf/prog_tests/btf_sysfs.c | 81 ++++++++++++++++++= ++++ 1 file changed, 81 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/btf_sysfs.c b/tools/tes= ting/selftests/bpf/prog_tests/btf_sysfs.c new file mode 100644 index 0000000000000000000000000000000000000000..3923e64c4c1d0f1dfeef2a39c7b= bab7c9a19f0ca --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/btf_sysfs.c @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause +/* Copyright (c) 2025 Isovalent */ + +#include +#include +#include +#include +#include +#include + +static void test_btf_mmap_sysfs(const char *path, struct btf *base) +{ + struct stat st; + __u64 btf_size, end; + void *raw_data =3D NULL; + int fd =3D -1; + long page_size; + struct btf *btf =3D NULL; + + page_size =3D sysconf(_SC_PAGESIZE); + if (!ASSERT_GE(page_size, 0, "get_page_size")) + goto cleanup; + + if (!ASSERT_OK(stat(path, &st), "stat_btf")) + goto cleanup; + + btf_size =3D st.st_size; + end =3D (btf_size + page_size - 1) / page_size * page_size; + + fd =3D open(path, O_RDONLY); + if (!ASSERT_GE(fd, 0, "open_btf")) + goto cleanup; + + raw_data =3D mmap(NULL, btf_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd= , 0); + if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_writable")) + goto cleanup; + + raw_data =3D mmap(NULL, btf_size, PROT_READ, MAP_SHARED, fd, 0); + if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_shared")) + goto cleanup; + + raw_data =3D mmap(NULL, end + 1, PROT_READ, MAP_PRIVATE, fd, 0); + if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_invalid_size")) + goto cleanup; + + raw_data =3D mmap(NULL, end, PROT_READ, MAP_PRIVATE, fd, 0); + if (!ASSERT_OK_PTR(raw_data, "mmap_btf")) + goto cleanup; + + if (!ASSERT_EQ(mprotect(raw_data, btf_size, PROT_READ | PROT_WRITE), -1, + "mprotect_writable")) + goto cleanup; + + if (!ASSERT_EQ(mprotect(raw_data, btf_size, PROT_READ | PROT_EXEC), -1, + "mprotect_executable")) + goto cleanup; + + /* Check padding is zeroed */ + for (int i =3D btf_size; i < end; i++) { + if (((__u8 *)raw_data)[i] !=3D 0) { + PRINT_FAIL("tail of BTF is not zero at page offset %d\n", i); + goto cleanup; + } + } + + btf =3D btf__new_split(raw_data, btf_size, base); + if (!ASSERT_OK_PTR(btf, "parse_btf")) + goto cleanup; + +cleanup: + btf__free(btf); + if (raw_data && raw_data !=3D MAP_FAILED) + munmap(raw_data, btf_size); + if (fd >=3D 0) + close(fd); +} + +void test_btf_sysfs(void) +{ + test_btf_mmap_sysfs("/sys/kernel/btf/vmlinux", NULL); +} --=20 2.49.0 From nobody Tue Dec 16 07:34:27 2025 Received: from mail-wr1-f50.google.com (mail-wr1-f50.google.com [209.85.221.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B286822D4CE for ; Tue, 20 May 2025 13:01:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.50 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747746106; cv=none; b=nBokcEauQgG7c7KnqE2zL9vcYPw+z1+HEXkGNMHk5NV+jQTzZ3wLBEmkYfN7Vk7Wk79Zt1zCMHCcN0MyZ4xklFsOxu/hsnjZyqf2uFUE/mHIF71eCF3aKUYH2QPYsZbyHcAyib5vHLFMMc15aHVkoUk7h6Tc62n6XAuSuBHmbOc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747746106; c=relaxed/simple; bh=/R6j9K4jScYvrR5J0W5As8DeDzzv9KIlQWuMdG/6/7o=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=gxHJvmkQK2BQfX6WuePPOEnkaTEO8hs6pcouCrAQcfJpuj541KIrNAB6mvazh8irBpXh2Y7tksue4JlEa85khrW2QQS8971o7Jy4Q2PowzR0QfF3TQfjgeft7N75KEo5J0nCunOnNrmTMciKWqU3PKRa0VFpVP9BmVYQ0OyvHWU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=isovalent.com; spf=pass smtp.mailfrom=isovalent.com; dkim=pass (2048-bit key) header.d=isovalent.com header.i=@isovalent.com header.b=i6zMAy8w; arc=none smtp.client-ip=209.85.221.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=isovalent.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=isovalent.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=isovalent.com header.i=@isovalent.com header.b="i6zMAy8w" Received: by mail-wr1-f50.google.com with SMTP id ffacd0b85a97d-3a375888297so1206223f8f.1 for ; Tue, 20 May 2025 06:01:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isovalent.com; s=google; t=1747746103; x=1748350903; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=ZpMtnil2qblYoO6Q14njX8XFYnavuQfuqbvg7JG/1LQ=; b=i6zMAy8w0IrgpFffBc8OdW0Bx2FLTKTJFcztC0QFQ+haUzlhZVdmUwHRRZfEOGNAY2 YOjyChNMR36jTp/j5I0jPyJusqlezQAd7XxTIBmftf7l4ZEvvc+QpT2ZIOYXYQkAHyNA DTA2wDqx3Dgzr6ZwzHQYJb0rFKK983ia+9io/oMdc5NSha04sQSBkgA/i5mEfG6BlZ3o 4n+jo0qB9ok65FAL4xylBmeZHcu2ldqUcQlSi9XZnu/qQA/0aoUYmBt3MSjiRnZ6cK1M 9wkOa99AZb7g/lngf+Kf0/jMzj3LYoPmSTu+8UV6FspSqNlwIPWxOYVtm5emUgMeHpL9 IOYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747746103; x=1748350903; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ZpMtnil2qblYoO6Q14njX8XFYnavuQfuqbvg7JG/1LQ=; b=Eyae7rxYzoWvSJqz7oBHpcEMW0Q7WqDBPBIIDubKmaQ3RRiPnOBiMHfv+6ZMyapw3t ZLODbstCswxI1OFPmY60QUl0yS7ATn1GmgnyMbNVxXv8hNOwY9QCegjEHcHw5ilRiZbD wpusBiusTRjIPsaoY3WzpkKd8uZOSaJb9mCgGUmP72x7LlpVQ4orUOHHEAaG9SUfbAss D3B9/qA45qzqkkS4uLu3lFosjb24oCGmJbeQcGkqFhX2T4gW73RaU9DBP2EyYr3bAY9H G9YfsC3cT1jGRWPD52xL1Y8CH4DYtlZK9JDQpKe9pueKKlh6p8j/MgtxvfdrhLWKvybL bZIg== X-Forwarded-Encrypted: i=1; AJvYcCUXdxwEn6ABVWjmy5KU1fqMfLRsJ70yhtpU4Ulng/XAaOUJoRE2qVBLlPP2mBwFcGxcvwakTrn51T1Xjh8=@vger.kernel.org X-Gm-Message-State: AOJu0YwiTQCXuINMpleeY5e6TxTpg1ob1oslj7z9btY4uptz91yusfpG xrSilk40olxzDc1blQJcXDmmESUpVJ2zQQy8KDerPwOFir1hl2fQYcbN4RiUht+GRhE= X-Gm-Gg: ASbGncun8jx6IZT/61/uruiT0F/bwLjypB0RWAKXK94As4ZS3z+PqVSPecgvofuoHUl Y7x1d7EvcioUdUVCZnB1wmaPD+W8PA3y4pbwqVErbrzc2yllN3/sWdO66ZSMWnv3ELhBxFjYh3c 6LUjGtmyCte/gtR6HODduQzTSnPYecDbTGQcpjtkRpkKOXnOfUAfGb4VOUjBPH2OCMLS6lyqyIF QEyr8DFUpWKPgPh4HWK7tQUEE4mm5gnfG4JOz7hfGBNjHeJkWaElMlGN8yWUUdKH9O98QOYdZ3Z iqnFqHVxVObAkv2159S+d2bsZQ037kFUEfmPDlxGMDqC39S2qUAYvNkXwnCLZl47418WGQGloVD Ps/ociw2h1ywtVvdbio9BxzdD1mhnNcnLwXdNPC9URExlj9Y= X-Google-Smtp-Source: AGHT+IG5+1GVi2mH8CpCHCfiaPZz/F4eS33pzARjBNR2zH29aTmr8kvRs43iZqFzkoNQ2RMuMcTeHg== X-Received: by 2002:a05:6000:2911:b0:3a3:6bff:9735 with SMTP id ffacd0b85a97d-3a36bff9995mr7410026f8f.10.1747746102260; Tue, 20 May 2025 06:01:42 -0700 (PDT) Received: from [192.168.1.240] (0.0.6.0.0.0.0.0.0.0.0.0.0.0.0.0.f.f.6.2.a.5.a.7.0.b.8.0.1.0.0.2.ip6.arpa. [2001:8b0:7a5a:26ff::600]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a35ca5a8cfsm16538095f8f.37.2025.05.20.06.01.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 May 2025 06:01:41 -0700 (PDT) From: Lorenz Bauer Date: Tue, 20 May 2025 14:01:19 +0100 Subject: [PATCH bpf-next v5 3/3] libbpf: Use mmap to parse vmlinux BTF from sysfs Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250520-vmlinux-mmap-v5-3-e8c941acc414@isovalent.com> References: <20250520-vmlinux-mmap-v5-0-e8c941acc414@isovalent.com> In-Reply-To: <20250520-vmlinux-mmap-v5-0-e8c941acc414@isovalent.com> To: Arnd Bergmann , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Lorenz Bauer , Alan Maguire X-Mailer: b4 0.14.2 Teach libbpf to use mmap when parsing vmlinux BTF from /sys. We don't apply this to fall-back paths on the regular file system because there is no way to ensure that modifications underlying the MAP_PRIVATE mapping are not visible to the process. Acked-by: Andrii Nakryiko Tested-by: Alan Maguire Signed-off-by: Lorenz Bauer --- tools/lib/bpf/btf.c | 89 ++++++++++++++++++++++++++++++++++++++++++-------= ---- 1 file changed, 71 insertions(+), 18 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index f18d7e6a453cd9e5c384487659df04f7efafdf5a..3b98ac40bbd66c4fa688f967f93= 70b5c92610ba0 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -120,6 +121,9 @@ struct btf { /* whether base_btf should be freed in btf_free for this instance */ bool owns_base; =20 + /* whether raw_data is a (read-only) mmap */ + bool raw_data_is_mmap; + /* BTF object FD, if loaded into kernel */ int fd; =20 @@ -951,6 +955,17 @@ static bool btf_is_modifiable(const struct btf *btf) return (void *)btf->hdr !=3D btf->raw_data; } =20 +static void btf_free_raw_data(struct btf *btf) +{ + if (btf->raw_data_is_mmap) { + munmap(btf->raw_data, btf->raw_size); + btf->raw_data_is_mmap =3D false; + } else { + free(btf->raw_data); + } + btf->raw_data =3D NULL; +} + void btf__free(struct btf *btf) { if (IS_ERR_OR_NULL(btf)) @@ -970,7 +985,7 @@ void btf__free(struct btf *btf) free(btf->types_data); strset__free(btf->strs_set); } - free(btf->raw_data); + btf_free_raw_data(btf); free(btf->raw_data_swapped); free(btf->type_offs); if (btf->owns_base) @@ -1030,7 +1045,7 @@ struct btf *btf__new_empty_split(struct btf *base_btf) return libbpf_ptr(btf_new_empty(base_btf)); } =20 -static struct btf *btf_new(const void *data, __u32 size, struct btf *base_= btf) +static struct btf *btf_new(const void *data, __u32 size, struct btf *base_= btf, bool is_mmap) { struct btf *btf; int err; @@ -1050,12 +1065,18 @@ static struct btf *btf_new(const void *data, __u32 = size, struct btf *base_btf) btf->start_str_off =3D base_btf->hdr->str_len; } =20 - btf->raw_data =3D malloc(size); - if (!btf->raw_data) { - err =3D -ENOMEM; - goto done; + if (is_mmap) { + btf->raw_data =3D (void *)data; + btf->raw_data_is_mmap =3D true; + } else { + btf->raw_data =3D malloc(size); + if (!btf->raw_data) { + err =3D -ENOMEM; + goto done; + } + memcpy(btf->raw_data, data, size); } - memcpy(btf->raw_data, data, size); + btf->raw_size =3D size; =20 btf->hdr =3D btf->raw_data; @@ -1083,12 +1104,12 @@ static struct btf *btf_new(const void *data, __u32 = size, struct btf *base_btf) =20 struct btf *btf__new(const void *data, __u32 size) { - return libbpf_ptr(btf_new(data, size, NULL)); + return libbpf_ptr(btf_new(data, size, NULL, false)); } =20 struct btf *btf__new_split(const void *data, __u32 size, struct btf *base_= btf) { - return libbpf_ptr(btf_new(data, size, base_btf)); + return libbpf_ptr(btf_new(data, size, base_btf, false)); } =20 struct btf_elf_secs { @@ -1209,7 +1230,7 @@ static struct btf *btf_parse_elf(const char *path, st= ruct btf *base_btf, =20 if (secs.btf_base_data) { dist_base_btf =3D btf_new(secs.btf_base_data->d_buf, secs.btf_base_data-= >d_size, - NULL); + NULL, false); if (IS_ERR(dist_base_btf)) { err =3D PTR_ERR(dist_base_btf); dist_base_btf =3D NULL; @@ -1218,7 +1239,7 @@ static struct btf *btf_parse_elf(const char *path, st= ruct btf *base_btf, } =20 btf =3D btf_new(secs.btf_data->d_buf, secs.btf_data->d_size, - dist_base_btf ?: base_btf); + dist_base_btf ?: base_btf, false); if (IS_ERR(btf)) { err =3D PTR_ERR(btf); goto done; @@ -1335,7 +1356,7 @@ static struct btf *btf_parse_raw(const char *path, st= ruct btf *base_btf) } =20 /* finally parse BTF data */ - btf =3D btf_new(data, sz, base_btf); + btf =3D btf_new(data, sz, base_btf, false); =20 err_out: free(data); @@ -1354,6 +1375,37 @@ struct btf *btf__parse_raw_split(const char *path, s= truct btf *base_btf) return libbpf_ptr(btf_parse_raw(path, base_btf)); } =20 +static struct btf *btf_parse_raw_mmap(const char *path, struct btf *base_b= tf) +{ + struct stat st; + void *data; + struct btf *btf; + int fd, err; + + fd =3D open(path, O_RDONLY); + if (fd < 0) + return libbpf_err_ptr(-errno); + + if (fstat(fd, &st) < 0) { + err =3D -errno; + close(fd); + return libbpf_err_ptr(err); + } + + data =3D mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); + err =3D -errno; + close(fd); + + if (data =3D=3D MAP_FAILED) + return libbpf_err_ptr(err); + + btf =3D btf_new(data, st.st_size, base_btf, true); + if (IS_ERR(btf)) + munmap(data, st.st_size); + + return btf; +} + static struct btf *btf_parse(const char *path, struct btf *base_btf, struc= t btf_ext **btf_ext) { struct btf *btf; @@ -1618,7 +1670,7 @@ struct btf *btf_get_from_fd(int btf_fd, struct btf *b= ase_btf) goto exit_free; } =20 - btf =3D btf_new(ptr, btf_info.btf_size, base_btf); + btf =3D btf_new(ptr, btf_info.btf_size, base_btf, false); =20 exit_free: free(ptr); @@ -1658,10 +1710,8 @@ struct btf *btf__load_from_kernel_by_id(__u32 id) =20 static void btf_invalidate_raw_data(struct btf *btf) { - if (btf->raw_data) { - free(btf->raw_data); - btf->raw_data =3D NULL; - } + if (btf->raw_data) + btf_free_raw_data(btf); if (btf->raw_data_swapped) { free(btf->raw_data_swapped); btf->raw_data_swapped =3D NULL; @@ -5331,7 +5381,10 @@ struct btf *btf__load_vmlinux_btf(void) pr_warn("kernel BTF is missing at '%s', was CONFIG_DEBUG_INFO_BTF enable= d?\n", sysfs_btf_path); } else { - btf =3D btf__parse(sysfs_btf_path, NULL); + btf =3D btf_parse_raw_mmap(sysfs_btf_path, NULL); + if (IS_ERR(btf)) + btf =3D btf__parse(sysfs_btf_path, NULL); + if (!btf) { err =3D -errno; pr_warn("failed to read kernel BTF from '%s': %s\n", --=20 2.49.0