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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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: D8EFB1A0004 X-Stat-Signature: 3tutbnbpukwndjsnkio6ox76tg37zt7u X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1779470545-573039 X-HE-Meta: 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 AbbM8VEn JOK6Jm08oHzjo4gKCgRNbwUOw1h/OcT0SQa/GAPF6YnXAh4e6CavvQyyQO361JE4UOXJWMr8tIsdI4Mo+aS9J226WT9S+D1ir+rXi33RbH4jipgQN1hkrLMJlxmKtJKCOxPRTmNAzuBePuhfsZBwGf/1c+7h6Wbqr0I9P+lbqG8N3ZciJxlpl31Sw/fwN6D11JCXuhO/AmLgsf+YwHfICs4nW7HsbRhquAQikiz+cfGGW/W9GluUymI15b3uCuzDZdwV/1+TmWF6B7DFFynhY3+nRr7NyL/5hooZqIPnmlxTQuVXt42/TGpzshveBGl1fCTWx+MUcqrV8Old2/tZcDm7xJfvmk4Fyxkl7jRHVbpxCFdg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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