From patchwork Fri May 2 10:20:05 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenz Bauer X-Patchwork-Id: 886787 Received: from mail-wr1-f53.google.com (mail-wr1-f53.google.com [209.85.221.53]) (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 04B8023BCE4 for ; Fri, 2 May 2025 10:20:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.53 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746181236; cv=none; b=WUo2+7zASr1lFPvxQ/mUInW50M0ETZhEHvmQPbNN6/U8/gN/ZW6D2IDMg1grKNoIgp9Ne3TgOesr36biFNNJoZwegk8TiUuPwkNnt32HsGQJzbUxn4+coUblrEJx53PLFbQRKWmkhEI1QZ5r1pyFRhoeJ2AL6Qjz560p1Ln2FLU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746181236; c=relaxed/simple; bh=Ylo3Ub/c876od9q4CA0Wfm+gRvKVrvDK1NgJ0c81mh8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=gy/PhfJaMYQrYkbVXD7Fkvmc+LaXE8YEgoIkDvg3CgjAVYl7A/F9A4vdhjJSwEqPakILkR7r+pv4IxZ6jb4WJZChYXfGYH54OTlTfdrdnrFTrsHfRzfPDVqqmkwyH9Ca7JtJ9If+sdkkk2QkXqswrexJ6Owsvq23rXC5o2Ey3TE= 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=dUcTnWQ1; arc=none smtp.client-ip=209.85.221.53 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="dUcTnWQ1" Received: by mail-wr1-f53.google.com with SMTP id ffacd0b85a97d-3914aba1ce4so1114843f8f.2 for ; Fri, 02 May 2025 03:20:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isovalent.com; s=google; t=1746181233; x=1746786033; 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=VD+xFPWezuPLNquEIvrdXCnLiFoEsA81xbyY7WvgQlY=; b=dUcTnWQ1cEAUu2Iu1iIMpVKJEAn9HH8XH9ncspHgXzZG1mTgwpV0lyseuvgrDHIZFn pW+TcZjzpbgSKZ3C84D0Bto+9iiuFGNB5N1veKm8pFM4dGU3Ku3sDzynI1KnlDanK9Bq 2T07kqYPbV7Pzq37vCiRdtTZYzxPGjHFb21q1/HYzdAg+A6bnwrr9YvGRauJ9Xm87DU/ PCy9AW/bBbm2Zv3NmN2mQoIBajB53xMBIDZqrxt1nalv6fEWRs3rjuLnNJyGRg6A0pvP qn2CE3k6PCchYuR4RyXQMYPB4+X+mDe34GdYS/vxm30KhIAKryJ8USUNY5zKbDmScGPC /sMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1746181233; x=1746786033; 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=VD+xFPWezuPLNquEIvrdXCnLiFoEsA81xbyY7WvgQlY=; b=UZD3pbqRZlquuqCyH7Ng8E6176XTR8RCnBNaIs7dHHJfxQ1w7e0r3F/zbVtIxyzZo+ B/wKa+ziM2rqjauh0DwfBt41Tu7QsAwILVcGY+Apdm4Mhxodob8zwB9hWOZW1LazoiyZ HF6ZYUtnjTnCt1/pv0xemIYiz/968gAsP6LqnrtY5rd/q0alZJ0Q2NZsHksd1deKeF5i xZvbl8vJL1uwpeC9k9PQ3GTvr5ABDM4foTP30y5EWFxemwyG91UXvy8BDb1X2GF2WAyi /OMUKrc7/slfjRDY9a66IHpycS9//1Flr6x0z98w0RwzwcEg9lkLatERs6xgWCTNqOKE u3Mw== X-Forwarded-Encrypted: i=1; AJvYcCWn7SG4hvjeUO+8nVUy0p1U7Y2+OdqaGn+lq74SKZgFwzX/70TmaLqMeoR7wYmxJJCpPv3Wxw91hc5gdJY0D+U=@vger.kernel.org X-Gm-Message-State: AOJu0YwWbpl5bFzOqS2MSOGu4d2MEmFsXGRDoh30dqQCAz2rh0SI7hRm LhxrbJShXHyiRQbf0yp5eGjq6ls591WZw5g2GqWTEov7mWCSAjTX9Az/wgfhAYU= X-Gm-Gg: ASbGnctbnrCSQdeGVZZ+ZKS/qG6TsAy4vY0GFSFDSpeExx7M76SdWrCCyvCMehB3s8n ne49R7FV8vnU2sZGWjYZpfc09Ot5/0Kr57e2XgAYF+JQscfntuLF70kT2YBj5pQwkBWiVUZ2p1f BDWE91aLalDCU3NhNtRealwMbO2uzj5EhFVpDPXa75HTKq1Zgn1IXL9F8mZWLJ4wFdfunHehn7c YD94dPlVkFYkOu8xta5IQjSkGdTODWLKw/6ee11jgtp9N5Ft4JciCeyXel591pQ7BWd10YIImKg rA2sqcXlAq6h213pTjonjiEpdeViKl5wIy8DiI5SimziDbihDLR3lnBPBlKep3ORsBWP3nRHfM6 5idh9EvAf4ipmEoET8eWGTo3FoYNjqfbIRyQaRUTFAJ/wLfc= X-Google-Smtp-Source: AGHT+IEgYQYFDekPsQClBf5vIZVQdcfJLacTov41mJCtxCQP8j+WAhf+6C7cqk20Ftn9GIBaFYncaw== X-Received: by 2002:a05:6000:2403:b0:3a0:831d:267c with SMTP id ffacd0b85a97d-3a099ad95cfmr1478745f8f.18.1746181233053; Fri, 02 May 2025 03:20:33 -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-3a099b17017sm1742342f8f.92.2025.05.02.03.20.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 May 2025 03:20:32 -0700 (PDT) From: Lorenz Bauer Date: Fri, 02 May 2025 11:20:05 +0100 Subject: [PATCH bpf-next v2 1/3] btf: allow mmap of vmlinux btf Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250502-vmlinux-mmap-v2-1-95c271434519@isovalent.com> References: <20250502-vmlinux-mmap-v2-0-95c271434519@isovalent.com> In-Reply-To: <20250502-vmlinux-mmap-v2-0-95c271434519@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 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. Signed-off-by: Lorenz Bauer --- include/asm-generic/vmlinux.lds.h | 3 ++- kernel/bpf/sysfs_btf.c | 36 ++++++++++++++++++++++++++++++++++-- 2 files changed, 36 insertions(+), 3 deletions(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 58a635a6d5bdf0c53c267c2a3d21a5ed8678ce73..1750390735fac7637cc4d2fa05f96cb2a36aa448 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_PROPELLER_CLANG) */ #ifdef CONFIG_DEBUG_INFO_BTF #define BTF \ + . = ALIGN(PAGE_SIZE); \ .BTF : AT(ADDR(.BTF) - LOAD_OFFSET) { \ BOUNDED_SECTION_BY(.BTF, _BTF) \ } \ - . = ALIGN(4); \ + . = 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..f4b59b1c2e5b11ffffa80662ad39334c730019ee 100644 --- a/kernel/bpf/sysfs_btf.c +++ b/kernel/bpf/sysfs_btf.c @@ -7,18 +7,50 @@ #include #include #include +#include +#include /* See scripts/link-vmlinux.sh, gen_btf() func for details */ extern char __start_BTF[]; extern char __stop_BTF[]; +struct kobject *btf_kobj; + +static int btf_vmlinux_mmap(struct file *filp, struct kobject *kobj, + const struct bin_attribute *attr, + struct vm_area_struct *vma) +{ + phys_addr_t start = virt_to_phys(__start_BTF); + size_t btf_size = __stop_BTF - __start_BTF; + size_t vm_size = vma->vm_end - vma->vm_start; + unsigned long pfn = start >> PAGE_SHIFT; + unsigned long pages = PAGE_ALIGN(btf_size) >> PAGE_SHIFT; + + if (kobj != btf_kobj) + 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_prot); +} + static struct bin_attribute bin_attr_btf_vmlinux __ro_after_init = { .attr = { .name = "vmlinux", .mode = 0444, }, .read_new = sysfs_bin_attr_simple_read, + .mmap = btf_vmlinux_mmap, }; -struct kobject *btf_kobj; - static int __init btf_vmlinux_init(void) { bin_attr_btf_vmlinux.private = __start_BTF; From patchwork Fri May 2 10:20:06 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenz Bauer X-Patchwork-Id: 887332 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 8436423C4E7 for ; Fri, 2 May 2025 10:20:35 +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=1746181237; cv=none; b=t10uIiNwU1zh8kaF72h3q/KX5rWO+xSRRO0roaMPXFiHoiNtnYN2v8CzHPuflsaJw4afTCsUvh+Nqu7wDTDffTWIC/hDrsqiUTmp+aehUuRsWYQ6M2QKE3GnYxIk3N2PibyO/eHU88O+D526bS5Y0mWrOOxVsdpnz/9zIC3fkBA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; 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Fri, 02 May 2025 03:20:33 -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-3a099b17017sm1742342f8f.92.2025.05.02.03.20.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 May 2025 03:20:33 -0700 (PDT) From: Lorenz Bauer Date: Fri, 02 May 2025 11:20:06 +0100 Subject: [PATCH bpf-next v2 2/3] selftests: bpf: add a test for mmapable vmlinux BTF Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250502-vmlinux-mmap-v2-2-95c271434519@isovalent.com> References: <20250502-vmlinux-mmap-v2-0-95c271434519@isovalent.com> In-Reply-To: <20250502-vmlinux-mmap-v2-0-95c271434519@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 X-Mailer: b4 0.14.2 Add a basic test for the ability to mmap /sys/kernel/btf/vmlinux. Since libbpf doesn't have an API to parse BTF from memory we do some basic sanity checks ourselves. Signed-off-by: Lorenz Bauer --- tools/testing/selftests/bpf/prog_tests/btf_sysfs.c | 82 ++++++++++++++++++++++ 1 file changed, 82 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/btf_sysfs.c b/tools/testing/selftests/bpf/prog_tests/btf_sysfs.c new file mode 100644 index 0000000000000000000000000000000000000000..5c8095bedb0517930aabdecc17ca7043f80f3692 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/btf_sysfs.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* Copyright (c) 2025 Isovalent */ + +#include +#include +#include +#include +#include +#include + +#define BTF_MAGIC 0xeB9F + +static const char *btf_path = "/sys/kernel/btf/vmlinux"; + +void test_btf_sysfs(void) +{ + struct stat st; + __u64 btf_size; + void *raw_data = NULL; + int fd = -1; + size_t trailing; + long page_size; + struct btf *btf = NULL; + + page_size = sysconf(_SC_PAGESIZE); + if (!ASSERT_GE(page_size, 0, "get_page_size")) + goto cleanup; + + if (!ASSERT_OK(stat(btf_path, &st), "stat_btf")) + goto cleanup; + + btf_size = st.st_size; + trailing = page_size - (btf_size % page_size) % page_size; + + fd = open(btf_path, O_RDONLY); + if (!ASSERT_GE(fd, 0, "open_btf")) + goto cleanup; + + raw_data = 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 = mmap(NULL, btf_size, PROT_READ, MAP_SHARED, fd, 0); + if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_shared")) + goto cleanup; + + raw_data = mmap(NULL, btf_size + trailing + 1, PROT_READ, MAP_PRIVATE, fd, 0); + if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_invalid_size")) + goto cleanup; + + raw_data = mmap(NULL, btf_size, PROT_READ, MAP_PRIVATE, fd, 0); + if (!ASSERT_NEQ(raw_data, MAP_FAILED, "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 = 0; i < trailing; i++) { + if (((__u8 *)raw_data)[btf_size + i] != 0) { + PRINT_FAIL("tail of BTF is not zero at page offset %d\n", i); + goto cleanup; + } + } + + btf = btf__new(raw_data, btf_size); + if (!ASSERT_NEQ(btf, NULL, "parse_btf")) + goto cleanup; + +cleanup: + if (raw_data && raw_data != MAP_FAILED) + munmap(raw_data, btf_size); + if (btf) + btf__free(btf); + if (fd >= 0) + close(fd); +} From patchwork Fri May 2 10:20:07 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenz Bauer X-Patchwork-Id: 886786 Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) (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 BE99623C517 for ; Fri, 2 May 2025 10:20:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.53 ARC-Seal: i=1; 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[2001:8b0:7a5a:26ff::600]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a099b17017sm1742342f8f.92.2025.05.02.03.20.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 May 2025 03:20:34 -0700 (PDT) From: Lorenz Bauer Date: Fri, 02 May 2025 11:20:07 +0100 Subject: [PATCH bpf-next v2 3/3] libbpf: Use mmap to parse vmlinux BTF from sysfs Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250502-vmlinux-mmap-v2-3-95c271434519@isovalent.com> References: <20250502-vmlinux-mmap-v2-0-95c271434519@isovalent.com> In-Reply-To: <20250502-vmlinux-mmap-v2-0-95c271434519@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 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. Signed-off-by: Lorenz Bauer --- tools/lib/bpf/btf.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 71 insertions(+), 11 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index b7513d4cce55b263310c341bc254df6364e829d9..7fec41a2dc617c9d388f9ab10d9850ef759c74d9 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; + /* whether raw_data is a (read-only) mmap */ + bool raw_data_is_mmap; + /* BTF object FD, if loaded into kernel */ int fd; @@ -951,6 +955,17 @@ static bool btf_is_modifiable(const struct btf *btf) return (void *)btf->hdr != btf->raw_data; } +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 = false; + } else { + free(btf->raw_data); + } + btf->raw_data = 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)); } -static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf) +static struct btf *btf_new_no_copy(void *data, __u32 size, struct btf *base_btf) { struct btf *btf; int err; @@ -1050,12 +1065,7 @@ static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf) btf->start_str_off = base_btf->hdr->str_len; } - btf->raw_data = malloc(size); - if (!btf->raw_data) { - err = -ENOMEM; - goto done; - } - memcpy(btf->raw_data, data, size); + btf->raw_data = data; btf->raw_size = size; btf->hdr = btf->raw_data; @@ -1081,6 +1091,24 @@ static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf) return btf; } +static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf) +{ + struct btf *btf; + void *raw_data; + + raw_data = malloc(size); + if (!raw_data) + return ERR_PTR(-ENOMEM); + + memcpy(raw_data, data, size); + + btf = btf_new_no_copy(raw_data, size, base_btf); + if (IS_ERR(btf)) + free(raw_data); + + return btf; +} + struct btf *btf__new(const void *data, __u32 size) { return libbpf_ptr(btf_new(data, size, NULL)); @@ -1659,8 +1687,7 @@ struct btf *btf__load_from_kernel_by_id(__u32 id) static void btf_invalidate_raw_data(struct btf *btf) { if (btf->raw_data) { - free(btf->raw_data); - btf->raw_data = NULL; + btf_free_raw_data(btf); } if (btf->raw_data_swapped) { free(btf->raw_data_swapped); @@ -5290,7 +5317,40 @@ struct btf *btf__load_vmlinux_btf(void) pr_warn("kernel BTF is missing at '%s', was CONFIG_DEBUG_INFO_BTF enabled?\n", sysfs_btf_path); } else { - btf = btf__parse(sysfs_btf_path, NULL); + struct stat st; + void *data = NULL; + int fd; + + fd = open(sysfs_btf_path, O_RDONLY); + if (fd < 0) { + err = -errno; + pr_warn("failed to open kernel BTF at '%s': %s\n", + sysfs_btf_path, errstr(err)); + return libbpf_err_ptr(err); + } + + if (fstat(fd, &st) < 0) { + err = -errno; + pr_warn("failed to stat kernel BTF at '%s': %s\n", + sysfs_btf_path, errstr(err)); + close(fd); + return libbpf_err_ptr(err); + } + + data = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); + close(fd); + + if (data != MAP_FAILED) { + btf = libbpf_ptr(btf_new_no_copy(data, st.st_size, NULL)); + if (!btf) + munmap(data, st.st_size); + else + btf->raw_data_is_mmap = true; + } else { + pr_debug("reading kernel BTF via file-based fallback\n"); + btf = btf__parse(sysfs_btf_path, NULL); + } + if (!btf) { err = -errno; pr_warn("failed to read kernel BTF from '%s': %s\n",