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 EFB313D5642; Wed, 20 May 2026 23:50:58 +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=1779321061; cv=none; b=iB10nJ70blfjBTs2fTg44ViCKk8J5BMOyinqjEyxM1A3eJRPJfdVj7EsSsYxRwQ2ekJ3DKC8plL/a3juOLw6ztrOqgu4QFrs3wdc8E1Q0sBTwIPZmuUhQqW9oFPpdZrDF+n3JGWRIsLxt6lNMlD6TsNT5avG3F8EQObUpdRYofI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779321061; c=relaxed/simple; bh=QWwQgVh96VCUpsX47ExcVfnVGC9kfcIxNuNG1PsbXrw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JokUYlFT9YrvzwPMWJUtgK4QDLHSKimdW/hY6NKfPUTb5QH54b3gzS7B3P1PAP4Q6M3YbtorOB5sY31XyLL0sVE7bA58Ka7f+i1dqp97Qsm8z6jd8Io9/BmhjbQwnuJX8g8RZC5gStwNO7YB7+aT4/OkFUjcEf6oVkPdvd6FKgY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CarpkMgw; 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="CarpkMgw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 350261F00A3D; Wed, 20 May 2026 23:50:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779321058; bh=C5B01WmAERz0FAb+2U36sWTc4ic5I5yhwvS5EjBXihQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CarpkMgwagcPzBChV2WOC+aDWnTKcWssSXw9EDJxPeAftz6tZwWo0Hee4ZFSXUQ3I HnhTDCKYTNW7RWkzmNZVWawH18BBPDqse6XoOT5OlE+jn8MKg5ZDLp/2vZgiCx/QyK 0+Zdj+kKCM7BbZXKYq4DduZ7FP+WaMchuCP6MkeEudGYAoY262qZ3w8acPGyMpAHyN 7RtOIxSsW3gI171HgViaiKPiVljtkUNyF99FHCszdkRNsZqP5T8csPiBfFRiVnfwfc f9lmVHGPx7XdDcAvI89S4O65OlQCXdZF9tKGfQ+h4e5Jo3EOpm5Um6rBY2kWgKGPeF ezXYZohGzAvlg== 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: Wed, 20 May 2026 13:50:49 -1000 Message-ID: <20260520235052.4180316-6-tj@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520235052.4180316-1-tj@kernel.org> References: <20260520235052.4180316-1-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 --- 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