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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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: 0F172180004 X-Rspamd-Server: rspam04 X-Stat-Signature: jmhb6mmk5kdrjeduuww938q81nsdqytt X-HE-Tag: 1779321058-163038 X-HE-Meta: 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 dUYAnut6 mXREbq6QZIofadtyHaThsmDNBWPlL1FSiy0QxuXCopX5HkdPaKC4qOK+104DoP6FNDtFmjVD6TqoZpFO7TOJYNSNx0tkKkFXtEk7Sfpvvp8uy5qwmLUlNBcSLf7on0AqQH6nMHYE11NRm0c1uF3DvbsKbx0RbWizGOlQ5+PfbRKzDgC0fz/+Kw2qSlR5okvqdVsohudQ3lAOrdLSCo1qmGRISjkOeMCmnR0n5Ly2sfh/A2Gfl6SZsyg4SibIsSd8xpH04YAo48eSv2lJzvA5cLRKdyTK0b3kFPFTNVCM9SG3OxxI= 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 --- 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