From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F41BB37418C; Fri, 22 May 2026 17:22:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779470547; cv=none; b=YoMmNu4FzhVbFXAi6fetbOYbJn8aV4FQbT2olSoYxulQFLCBY0r8gVJqGo19mnAY0xO/a8LOhy549cUc5lbjdFtdRxc/Hgmh5sVQkYCXUSNtr1WFYQNiR13roPWpn0nIWE5dLyUNHX6SnWptFv6A1oC5uUgqj+yEienbjj3G5qY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779470547; c=relaxed/simple; bh=xLMpuULhE50WLvYfq+YFqn7p7F8PYDLxPc64udyrmVY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Y6hIICaUtCcuD8VK1gLC/dL5hpkYhMsh6+R89WXMvuqzYcXHoIMmLfoBQlPIul33CkIGffzKzjEjSjyJqVGewX/gHNq2cOU3Wjh7GjBCA0Zp3WPTcnV/kuz7RKyXnkEMQSzQdhjliSiuq/FryBgQJBdrss16gXYO/8j40kqDIik= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CHkuq/3z; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CHkuq/3z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E0C931F00A3D; Fri, 22 May 2026 17:22:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779470545; bh=zm3BzxzciLeqiOYKZgLYww3y6avzhR84hmtwyjfLNMI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CHkuq/3zZYu/tRxaWyme0lClSoZ0f6h5jg484VOcpHXU30VoknM2GFr4KTyBJOCg0 pODNVlk82hBzz+B/IkrEooAig0AaETfYG/V2xQXvehxL/amJMLboo4FRDSPj0s41Eo WYggiBT3FzncTdEWCwMeyjR/KkpllOwXPPldaepFhHrqWcprNjHxsH5/eYNQd7lNRc 15oqbf0wLQ+y4HXrMQ0NcdN2Oy6zEZChEQqb9q2j0yUcK8LEeZD2KqJlkgW+/VmNvt ZGu/cIlP5U+auQscBl37W+uJpTUdDzGuiXjeBLc3n9CQFxLNcz6zzcrRJJNB8ui1PH 93VAkSA7bstCw== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Kumar Kartikeya Dwivedi Cc: Peter Zijlstra , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andrew Morton , David Hildenbrand , Mike Rapoport , Emil Tsalapatis , sched-ext@lists.linux.dev, bpf@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 5/8] bpf/arena: Add bpf_arena_map_kern_vm_start() and bpf_prog_arena() Date: Fri, 22 May 2026 07:22:16 -1000 Message-ID: <20260522172219.1423324-6-tj@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260522172219.1423324-1-tj@kernel.org> References: <20260522172219.1423324-1-tj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit struct bpf_arena is opaque to callers outside arena.c. Add two helpers for struct_ops subsystems that need to reach into an arena: bpf_arena_map_kern_vm_start(struct bpf_map *map) returns @map's kern_vm_start. A sched_ext follow-up needs this to translate kern_va <-> uaddr. bpf_prog_arena(struct bpf_prog *prog) returns the bpf_map of the arena referenced by @prog (NULL if @prog references no arena). The verifier enforces at most one arena per program. Used by struct_ops callers that auto-discover an arena from a member prog and need to take a map reference. Suggested-by: Kumar Kartikeya Dwivedi Signed-off-by: Tejun Heo Reviewed-by: Emil Tsalapatis --- include/linux/bpf.h | 2 ++ kernel/bpf/arena.c | 26 ++++++++++++++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 5b99d786e98c..e1ba57c10aaa 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -618,6 +618,8 @@ void bpf_rb_root_free(const struct btf_field *field, void *rb_root, struct bpf_spin_lock *spin_lock); u64 bpf_arena_get_kern_vm_start(struct bpf_arena *arena); u64 bpf_arena_get_user_vm_start(struct bpf_arena *arena); +u64 bpf_arena_map_kern_vm_start(struct bpf_map *map); +struct bpf_map *bpf_prog_arena(struct bpf_prog *prog); int bpf_obj_name_cpy(char *dst, const char *src, unsigned int size); struct bpf_offload_dev; diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c index a811cf6170fa..51b9ae36feb6 100644 --- a/kernel/bpf/arena.c +++ b/kernel/bpf/arena.c @@ -84,6 +84,32 @@ u64 bpf_arena_get_user_vm_start(struct bpf_arena *arena) return arena ? arena->user_vm_start : 0; } +/** + * bpf_arena_map_kern_vm_start - kern_vm_start lookup by struct bpf_map * + * @map: a BPF_MAP_TYPE_ARENA map + * + * Return @map's kern_vm_start. + */ +u64 bpf_arena_map_kern_vm_start(struct bpf_map *map) +{ + return bpf_arena_get_kern_vm_start(container_of(map, struct bpf_arena, map)); +} + +/** + * bpf_prog_arena - return the bpf_map of the arena referenced by @prog + * @prog: a loaded BPF program + * + * The verifier enforces at most one arena per program and stores it in + * prog->aux->arena. Return that arena's underlying bpf_map, or NULL if + * @prog does not reference an arena. + */ +struct bpf_map *bpf_prog_arena(struct bpf_prog *prog) +{ + struct bpf_arena *arena = prog->aux->arena; + + return arena ? &arena->map : NULL; +} + static long arena_map_peek_elem(struct bpf_map *map, void *value) { return -EOPNOTSUPP; -- 2.54.0