1457f4436SAndrii Nakryiko #include <linux/bpf.h> 2457f4436SAndrii Nakryiko #include <linux/btf.h> 3457f4436SAndrii Nakryiko #include <linux/err.h> 4457f4436SAndrii Nakryiko #include <linux/irq_work.h> 5457f4436SAndrii Nakryiko #include <linux/slab.h> 6457f4436SAndrii Nakryiko #include <linux/filter.h> 7457f4436SAndrii Nakryiko #include <linux/mm.h> 8457f4436SAndrii Nakryiko #include <linux/vmalloc.h> 9457f4436SAndrii Nakryiko #include <linux/wait.h> 10457f4436SAndrii Nakryiko #include <linux/poll.h> 11457f4436SAndrii Nakryiko #include <uapi/linux/btf.h> 12457f4436SAndrii Nakryiko 13457f4436SAndrii Nakryiko #define RINGBUF_CREATE_FLAG_MASK (BPF_F_NUMA_NODE) 14457f4436SAndrii Nakryiko 15457f4436SAndrii Nakryiko /* non-mmap()'able part of bpf_ringbuf (everything up to consumer page) */ 16457f4436SAndrii Nakryiko #define RINGBUF_PGOFF \ 17457f4436SAndrii Nakryiko (offsetof(struct bpf_ringbuf, consumer_pos) >> PAGE_SHIFT) 18457f4436SAndrii Nakryiko /* consumer page and producer page */ 19457f4436SAndrii Nakryiko #define RINGBUF_POS_PAGES 2 20457f4436SAndrii Nakryiko 21457f4436SAndrii Nakryiko #define RINGBUF_MAX_RECORD_SZ (UINT_MAX/4) 22457f4436SAndrii Nakryiko 23457f4436SAndrii Nakryiko /* Maximum size of ring buffer area is limited by 32-bit page offset within 24457f4436SAndrii Nakryiko * record header, counted in pages. Reserve 8 bits for extensibility, and take 25457f4436SAndrii Nakryiko * into account few extra pages for consumer/producer pages and 26457f4436SAndrii Nakryiko * non-mmap()'able parts. This gives 64GB limit, which seems plenty for single 27457f4436SAndrii Nakryiko * ring buffer. 28457f4436SAndrii Nakryiko */ 29457f4436SAndrii Nakryiko #define RINGBUF_MAX_DATA_SZ \ 30457f4436SAndrii Nakryiko (((1ULL << 24) - RINGBUF_POS_PAGES - RINGBUF_PGOFF) * PAGE_SIZE) 31457f4436SAndrii Nakryiko 32457f4436SAndrii Nakryiko struct bpf_ringbuf { 33457f4436SAndrii Nakryiko wait_queue_head_t waitq; 34457f4436SAndrii Nakryiko struct irq_work work; 35457f4436SAndrii Nakryiko u64 mask; 36457f4436SAndrii Nakryiko struct page **pages; 37457f4436SAndrii Nakryiko int nr_pages; 38457f4436SAndrii Nakryiko spinlock_t spinlock ____cacheline_aligned_in_smp; 39457f4436SAndrii Nakryiko /* Consumer and producer counters are put into separate pages to allow 40457f4436SAndrii Nakryiko * mapping consumer page as r/w, but restrict producer page to r/o. 41457f4436SAndrii Nakryiko * This protects producer position from being modified by user-space 42457f4436SAndrii Nakryiko * application and ruining in-kernel position tracking. 43457f4436SAndrii Nakryiko */ 44457f4436SAndrii Nakryiko unsigned long consumer_pos __aligned(PAGE_SIZE); 45457f4436SAndrii Nakryiko unsigned long producer_pos __aligned(PAGE_SIZE); 46457f4436SAndrii Nakryiko char data[] __aligned(PAGE_SIZE); 47457f4436SAndrii Nakryiko }; 48457f4436SAndrii Nakryiko 49457f4436SAndrii Nakryiko struct bpf_ringbuf_map { 50457f4436SAndrii Nakryiko struct bpf_map map; 51457f4436SAndrii Nakryiko struct bpf_map_memory memory; 52457f4436SAndrii Nakryiko struct bpf_ringbuf *rb; 53457f4436SAndrii Nakryiko }; 54457f4436SAndrii Nakryiko 55457f4436SAndrii Nakryiko /* 8-byte ring buffer record header structure */ 56457f4436SAndrii Nakryiko struct bpf_ringbuf_hdr { 57457f4436SAndrii Nakryiko u32 len; 58457f4436SAndrii Nakryiko u32 pg_off; 59457f4436SAndrii Nakryiko }; 60457f4436SAndrii Nakryiko 61457f4436SAndrii Nakryiko static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node) 62457f4436SAndrii Nakryiko { 63457f4436SAndrii Nakryiko const gfp_t flags = GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN | 64457f4436SAndrii Nakryiko __GFP_ZERO; 65457f4436SAndrii Nakryiko int nr_meta_pages = RINGBUF_PGOFF + RINGBUF_POS_PAGES; 66457f4436SAndrii Nakryiko int nr_data_pages = data_sz >> PAGE_SHIFT; 67457f4436SAndrii Nakryiko int nr_pages = nr_meta_pages + nr_data_pages; 68457f4436SAndrii Nakryiko struct page **pages, *page; 69457f4436SAndrii Nakryiko struct bpf_ringbuf *rb; 70457f4436SAndrii Nakryiko size_t array_size; 71457f4436SAndrii Nakryiko int i; 72457f4436SAndrii Nakryiko 73457f4436SAndrii Nakryiko /* Each data page is mapped twice to allow "virtual" 74457f4436SAndrii Nakryiko * continuous read of samples wrapping around the end of ring 75457f4436SAndrii Nakryiko * buffer area: 76457f4436SAndrii Nakryiko * ------------------------------------------------------ 77457f4436SAndrii Nakryiko * | meta pages | real data pages | same data pages | 78457f4436SAndrii Nakryiko * ------------------------------------------------------ 79457f4436SAndrii Nakryiko * | | 1 2 3 4 5 6 7 8 9 | 1 2 3 4 5 6 7 8 9 | 80457f4436SAndrii Nakryiko * ------------------------------------------------------ 81457f4436SAndrii Nakryiko * | | TA DA | TA DA | 82457f4436SAndrii Nakryiko * ------------------------------------------------------ 83457f4436SAndrii Nakryiko * ^^^^^^^ 84457f4436SAndrii Nakryiko * | 85457f4436SAndrii Nakryiko * Here, no need to worry about special handling of wrapped-around 86457f4436SAndrii Nakryiko * data due to double-mapped data pages. This works both in kernel and 87457f4436SAndrii Nakryiko * when mmap()'ed in user-space, simplifying both kernel and 88457f4436SAndrii Nakryiko * user-space implementations significantly. 89457f4436SAndrii Nakryiko */ 90457f4436SAndrii Nakryiko array_size = (nr_meta_pages + 2 * nr_data_pages) * sizeof(*pages); 91457f4436SAndrii Nakryiko if (array_size > PAGE_SIZE) 92457f4436SAndrii Nakryiko pages = vmalloc_node(array_size, numa_node); 93457f4436SAndrii Nakryiko else 94457f4436SAndrii Nakryiko pages = kmalloc_node(array_size, flags, numa_node); 95457f4436SAndrii Nakryiko if (!pages) 96457f4436SAndrii Nakryiko return NULL; 97457f4436SAndrii Nakryiko 98457f4436SAndrii Nakryiko for (i = 0; i < nr_pages; i++) { 99457f4436SAndrii Nakryiko page = alloc_pages_node(numa_node, flags, 0); 100457f4436SAndrii Nakryiko if (!page) { 101457f4436SAndrii Nakryiko nr_pages = i; 102457f4436SAndrii Nakryiko goto err_free_pages; 103457f4436SAndrii Nakryiko } 104457f4436SAndrii Nakryiko pages[i] = page; 105457f4436SAndrii Nakryiko if (i >= nr_meta_pages) 106457f4436SAndrii Nakryiko pages[nr_data_pages + i] = page; 107457f4436SAndrii Nakryiko } 108457f4436SAndrii Nakryiko 109457f4436SAndrii Nakryiko rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages, 110457f4436SAndrii Nakryiko VM_ALLOC | VM_USERMAP, PAGE_KERNEL); 111457f4436SAndrii Nakryiko if (rb) { 112457f4436SAndrii Nakryiko rb->pages = pages; 113457f4436SAndrii Nakryiko rb->nr_pages = nr_pages; 114457f4436SAndrii Nakryiko return rb; 115457f4436SAndrii Nakryiko } 116457f4436SAndrii Nakryiko 117457f4436SAndrii Nakryiko err_free_pages: 118457f4436SAndrii Nakryiko for (i = 0; i < nr_pages; i++) 119457f4436SAndrii Nakryiko __free_page(pages[i]); 120457f4436SAndrii Nakryiko kvfree(pages); 121457f4436SAndrii Nakryiko return NULL; 122457f4436SAndrii Nakryiko } 123457f4436SAndrii Nakryiko 124457f4436SAndrii Nakryiko static void bpf_ringbuf_notify(struct irq_work *work) 125457f4436SAndrii Nakryiko { 126457f4436SAndrii Nakryiko struct bpf_ringbuf *rb = container_of(work, struct bpf_ringbuf, work); 127457f4436SAndrii Nakryiko 128457f4436SAndrii Nakryiko wake_up_all(&rb->waitq); 129457f4436SAndrii Nakryiko } 130457f4436SAndrii Nakryiko 131457f4436SAndrii Nakryiko static struct bpf_ringbuf *bpf_ringbuf_alloc(size_t data_sz, int numa_node) 132457f4436SAndrii Nakryiko { 133457f4436SAndrii Nakryiko struct bpf_ringbuf *rb; 134457f4436SAndrii Nakryiko 135457f4436SAndrii Nakryiko if (!data_sz || !PAGE_ALIGNED(data_sz)) 136457f4436SAndrii Nakryiko return ERR_PTR(-EINVAL); 137457f4436SAndrii Nakryiko 138457f4436SAndrii Nakryiko #ifdef CONFIG_64BIT 139457f4436SAndrii Nakryiko /* on 32-bit arch, it's impossible to overflow record's hdr->pgoff */ 140457f4436SAndrii Nakryiko if (data_sz > RINGBUF_MAX_DATA_SZ) 141457f4436SAndrii Nakryiko return ERR_PTR(-E2BIG); 142457f4436SAndrii Nakryiko #endif 143457f4436SAndrii Nakryiko 144457f4436SAndrii Nakryiko rb = bpf_ringbuf_area_alloc(data_sz, numa_node); 145457f4436SAndrii Nakryiko if (!rb) 146457f4436SAndrii Nakryiko return ERR_PTR(-ENOMEM); 147457f4436SAndrii Nakryiko 148457f4436SAndrii Nakryiko spin_lock_init(&rb->spinlock); 149457f4436SAndrii Nakryiko init_waitqueue_head(&rb->waitq); 150457f4436SAndrii Nakryiko init_irq_work(&rb->work, bpf_ringbuf_notify); 151457f4436SAndrii Nakryiko 152457f4436SAndrii Nakryiko rb->mask = data_sz - 1; 153457f4436SAndrii Nakryiko rb->consumer_pos = 0; 154457f4436SAndrii Nakryiko rb->producer_pos = 0; 155457f4436SAndrii Nakryiko 156457f4436SAndrii Nakryiko return rb; 157457f4436SAndrii Nakryiko } 158457f4436SAndrii Nakryiko 159457f4436SAndrii Nakryiko static struct bpf_map *ringbuf_map_alloc(union bpf_attr *attr) 160457f4436SAndrii Nakryiko { 161457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 162457f4436SAndrii Nakryiko u64 cost; 163457f4436SAndrii Nakryiko int err; 164457f4436SAndrii Nakryiko 165457f4436SAndrii Nakryiko if (attr->map_flags & ~RINGBUF_CREATE_FLAG_MASK) 166457f4436SAndrii Nakryiko return ERR_PTR(-EINVAL); 167457f4436SAndrii Nakryiko 168457f4436SAndrii Nakryiko if (attr->key_size || attr->value_size || 169457f4436SAndrii Nakryiko attr->max_entries == 0 || !PAGE_ALIGNED(attr->max_entries)) 170457f4436SAndrii Nakryiko return ERR_PTR(-EINVAL); 171457f4436SAndrii Nakryiko 172457f4436SAndrii Nakryiko rb_map = kzalloc(sizeof(*rb_map), GFP_USER); 173457f4436SAndrii Nakryiko if (!rb_map) 174457f4436SAndrii Nakryiko return ERR_PTR(-ENOMEM); 175457f4436SAndrii Nakryiko 176457f4436SAndrii Nakryiko bpf_map_init_from_attr(&rb_map->map, attr); 177457f4436SAndrii Nakryiko 178457f4436SAndrii Nakryiko cost = sizeof(struct bpf_ringbuf_map) + 179457f4436SAndrii Nakryiko sizeof(struct bpf_ringbuf) + 180457f4436SAndrii Nakryiko attr->max_entries; 181457f4436SAndrii Nakryiko err = bpf_map_charge_init(&rb_map->map.memory, cost); 182457f4436SAndrii Nakryiko if (err) 183457f4436SAndrii Nakryiko goto err_free_map; 184457f4436SAndrii Nakryiko 185457f4436SAndrii Nakryiko rb_map->rb = bpf_ringbuf_alloc(attr->max_entries, rb_map->map.numa_node); 186457f4436SAndrii Nakryiko if (IS_ERR(rb_map->rb)) { 187457f4436SAndrii Nakryiko err = PTR_ERR(rb_map->rb); 188457f4436SAndrii Nakryiko goto err_uncharge; 189457f4436SAndrii Nakryiko } 190457f4436SAndrii Nakryiko 191457f4436SAndrii Nakryiko return &rb_map->map; 192457f4436SAndrii Nakryiko 193457f4436SAndrii Nakryiko err_uncharge: 194457f4436SAndrii Nakryiko bpf_map_charge_finish(&rb_map->map.memory); 195457f4436SAndrii Nakryiko err_free_map: 196457f4436SAndrii Nakryiko kfree(rb_map); 197457f4436SAndrii Nakryiko return ERR_PTR(err); 198457f4436SAndrii Nakryiko } 199457f4436SAndrii Nakryiko 200457f4436SAndrii Nakryiko static void bpf_ringbuf_free(struct bpf_ringbuf *rb) 201457f4436SAndrii Nakryiko { 202457f4436SAndrii Nakryiko /* copy pages pointer and nr_pages to local variable, as we are going 203457f4436SAndrii Nakryiko * to unmap rb itself with vunmap() below 204457f4436SAndrii Nakryiko */ 205457f4436SAndrii Nakryiko struct page **pages = rb->pages; 206457f4436SAndrii Nakryiko int i, nr_pages = rb->nr_pages; 207457f4436SAndrii Nakryiko 208457f4436SAndrii Nakryiko vunmap(rb); 209457f4436SAndrii Nakryiko for (i = 0; i < nr_pages; i++) 210457f4436SAndrii Nakryiko __free_page(pages[i]); 211457f4436SAndrii Nakryiko kvfree(pages); 212457f4436SAndrii Nakryiko } 213457f4436SAndrii Nakryiko 214457f4436SAndrii Nakryiko static void ringbuf_map_free(struct bpf_map *map) 215457f4436SAndrii Nakryiko { 216457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 217457f4436SAndrii Nakryiko 218457f4436SAndrii Nakryiko /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, 219457f4436SAndrii Nakryiko * so the programs (can be more than one that used this map) were 220457f4436SAndrii Nakryiko * disconnected from events. Wait for outstanding critical sections in 221457f4436SAndrii Nakryiko * these programs to complete 222457f4436SAndrii Nakryiko */ 223457f4436SAndrii Nakryiko synchronize_rcu(); 224457f4436SAndrii Nakryiko 225457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 226457f4436SAndrii Nakryiko bpf_ringbuf_free(rb_map->rb); 227457f4436SAndrii Nakryiko kfree(rb_map); 228457f4436SAndrii Nakryiko } 229457f4436SAndrii Nakryiko 230457f4436SAndrii Nakryiko static void *ringbuf_map_lookup_elem(struct bpf_map *map, void *key) 231457f4436SAndrii Nakryiko { 232457f4436SAndrii Nakryiko return ERR_PTR(-ENOTSUPP); 233457f4436SAndrii Nakryiko } 234457f4436SAndrii Nakryiko 235457f4436SAndrii Nakryiko static int ringbuf_map_update_elem(struct bpf_map *map, void *key, void *value, 236457f4436SAndrii Nakryiko u64 flags) 237457f4436SAndrii Nakryiko { 238457f4436SAndrii Nakryiko return -ENOTSUPP; 239457f4436SAndrii Nakryiko } 240457f4436SAndrii Nakryiko 241457f4436SAndrii Nakryiko static int ringbuf_map_delete_elem(struct bpf_map *map, void *key) 242457f4436SAndrii Nakryiko { 243457f4436SAndrii Nakryiko return -ENOTSUPP; 244457f4436SAndrii Nakryiko } 245457f4436SAndrii Nakryiko 246457f4436SAndrii Nakryiko static int ringbuf_map_get_next_key(struct bpf_map *map, void *key, 247457f4436SAndrii Nakryiko void *next_key) 248457f4436SAndrii Nakryiko { 249457f4436SAndrii Nakryiko return -ENOTSUPP; 250457f4436SAndrii Nakryiko } 251457f4436SAndrii Nakryiko 252457f4436SAndrii Nakryiko static size_t bpf_ringbuf_mmap_page_cnt(const struct bpf_ringbuf *rb) 253457f4436SAndrii Nakryiko { 254457f4436SAndrii Nakryiko size_t data_pages = (rb->mask + 1) >> PAGE_SHIFT; 255457f4436SAndrii Nakryiko 256457f4436SAndrii Nakryiko /* consumer page + producer page + 2 x data pages */ 257457f4436SAndrii Nakryiko return RINGBUF_POS_PAGES + 2 * data_pages; 258457f4436SAndrii Nakryiko } 259457f4436SAndrii Nakryiko 260457f4436SAndrii Nakryiko static int ringbuf_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) 261457f4436SAndrii Nakryiko { 262457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 263457f4436SAndrii Nakryiko size_t mmap_sz; 264457f4436SAndrii Nakryiko 265457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 266457f4436SAndrii Nakryiko mmap_sz = bpf_ringbuf_mmap_page_cnt(rb_map->rb) << PAGE_SHIFT; 267457f4436SAndrii Nakryiko 268457f4436SAndrii Nakryiko if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) > mmap_sz) 269457f4436SAndrii Nakryiko return -EINVAL; 270457f4436SAndrii Nakryiko 271457f4436SAndrii Nakryiko return remap_vmalloc_range(vma, rb_map->rb, 272457f4436SAndrii Nakryiko vma->vm_pgoff + RINGBUF_PGOFF); 273457f4436SAndrii Nakryiko } 274457f4436SAndrii Nakryiko 275457f4436SAndrii Nakryiko static unsigned long ringbuf_avail_data_sz(struct bpf_ringbuf *rb) 276457f4436SAndrii Nakryiko { 277457f4436SAndrii Nakryiko unsigned long cons_pos, prod_pos; 278457f4436SAndrii Nakryiko 279457f4436SAndrii Nakryiko cons_pos = smp_load_acquire(&rb->consumer_pos); 280457f4436SAndrii Nakryiko prod_pos = smp_load_acquire(&rb->producer_pos); 281457f4436SAndrii Nakryiko return prod_pos - cons_pos; 282457f4436SAndrii Nakryiko } 283457f4436SAndrii Nakryiko 284457f4436SAndrii Nakryiko static __poll_t ringbuf_map_poll(struct bpf_map *map, struct file *filp, 285457f4436SAndrii Nakryiko struct poll_table_struct *pts) 286457f4436SAndrii Nakryiko { 287457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 288457f4436SAndrii Nakryiko 289457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 290457f4436SAndrii Nakryiko poll_wait(filp, &rb_map->rb->waitq, pts); 291457f4436SAndrii Nakryiko 292457f4436SAndrii Nakryiko if (ringbuf_avail_data_sz(rb_map->rb)) 293457f4436SAndrii Nakryiko return EPOLLIN | EPOLLRDNORM; 294457f4436SAndrii Nakryiko return 0; 295457f4436SAndrii Nakryiko } 296457f4436SAndrii Nakryiko 297457f4436SAndrii Nakryiko const struct bpf_map_ops ringbuf_map_ops = { 298457f4436SAndrii Nakryiko .map_alloc = ringbuf_map_alloc, 299457f4436SAndrii Nakryiko .map_free = ringbuf_map_free, 300457f4436SAndrii Nakryiko .map_mmap = ringbuf_map_mmap, 301457f4436SAndrii Nakryiko .map_poll = ringbuf_map_poll, 302457f4436SAndrii Nakryiko .map_lookup_elem = ringbuf_map_lookup_elem, 303457f4436SAndrii Nakryiko .map_update_elem = ringbuf_map_update_elem, 304457f4436SAndrii Nakryiko .map_delete_elem = ringbuf_map_delete_elem, 305457f4436SAndrii Nakryiko .map_get_next_key = ringbuf_map_get_next_key, 306457f4436SAndrii Nakryiko }; 307457f4436SAndrii Nakryiko 308457f4436SAndrii Nakryiko /* Given pointer to ring buffer record metadata and struct bpf_ringbuf itself, 309457f4436SAndrii Nakryiko * calculate offset from record metadata to ring buffer in pages, rounded 310457f4436SAndrii Nakryiko * down. This page offset is stored as part of record metadata and allows to 311457f4436SAndrii Nakryiko * restore struct bpf_ringbuf * from record pointer. This page offset is 312457f4436SAndrii Nakryiko * stored at offset 4 of record metadata header. 313457f4436SAndrii Nakryiko */ 314457f4436SAndrii Nakryiko static size_t bpf_ringbuf_rec_pg_off(struct bpf_ringbuf *rb, 315457f4436SAndrii Nakryiko struct bpf_ringbuf_hdr *hdr) 316457f4436SAndrii Nakryiko { 317457f4436SAndrii Nakryiko return ((void *)hdr - (void *)rb) >> PAGE_SHIFT; 318457f4436SAndrii Nakryiko } 319457f4436SAndrii Nakryiko 320457f4436SAndrii Nakryiko /* Given pointer to ring buffer record header, restore pointer to struct 321457f4436SAndrii Nakryiko * bpf_ringbuf itself by using page offset stored at offset 4 322457f4436SAndrii Nakryiko */ 323457f4436SAndrii Nakryiko static struct bpf_ringbuf * 324457f4436SAndrii Nakryiko bpf_ringbuf_restore_from_rec(struct bpf_ringbuf_hdr *hdr) 325457f4436SAndrii Nakryiko { 326457f4436SAndrii Nakryiko unsigned long addr = (unsigned long)(void *)hdr; 327457f4436SAndrii Nakryiko unsigned long off = (unsigned long)hdr->pg_off << PAGE_SHIFT; 328457f4436SAndrii Nakryiko 329457f4436SAndrii Nakryiko return (void*)((addr & PAGE_MASK) - off); 330457f4436SAndrii Nakryiko } 331457f4436SAndrii Nakryiko 332457f4436SAndrii Nakryiko static void *__bpf_ringbuf_reserve(struct bpf_ringbuf *rb, u64 size) 333457f4436SAndrii Nakryiko { 334457f4436SAndrii Nakryiko unsigned long cons_pos, prod_pos, new_prod_pos, flags; 335457f4436SAndrii Nakryiko u32 len, pg_off; 336457f4436SAndrii Nakryiko struct bpf_ringbuf_hdr *hdr; 337457f4436SAndrii Nakryiko 338457f4436SAndrii Nakryiko if (unlikely(size > RINGBUF_MAX_RECORD_SZ)) 339457f4436SAndrii Nakryiko return NULL; 340457f4436SAndrii Nakryiko 341457f4436SAndrii Nakryiko len = round_up(size + BPF_RINGBUF_HDR_SZ, 8); 342457f4436SAndrii Nakryiko cons_pos = smp_load_acquire(&rb->consumer_pos); 343457f4436SAndrii Nakryiko 344457f4436SAndrii Nakryiko if (in_nmi()) { 345457f4436SAndrii Nakryiko if (!spin_trylock_irqsave(&rb->spinlock, flags)) 346457f4436SAndrii Nakryiko return NULL; 347457f4436SAndrii Nakryiko } else { 348457f4436SAndrii Nakryiko spin_lock_irqsave(&rb->spinlock, flags); 349457f4436SAndrii Nakryiko } 350457f4436SAndrii Nakryiko 351457f4436SAndrii Nakryiko prod_pos = rb->producer_pos; 352457f4436SAndrii Nakryiko new_prod_pos = prod_pos + len; 353457f4436SAndrii Nakryiko 354457f4436SAndrii Nakryiko /* check for out of ringbuf space by ensuring producer position 355457f4436SAndrii Nakryiko * doesn't advance more than (ringbuf_size - 1) ahead 356457f4436SAndrii Nakryiko */ 357457f4436SAndrii Nakryiko if (new_prod_pos - cons_pos > rb->mask) { 358457f4436SAndrii Nakryiko spin_unlock_irqrestore(&rb->spinlock, flags); 359457f4436SAndrii Nakryiko return NULL; 360457f4436SAndrii Nakryiko } 361457f4436SAndrii Nakryiko 362457f4436SAndrii Nakryiko hdr = (void *)rb->data + (prod_pos & rb->mask); 363457f4436SAndrii Nakryiko pg_off = bpf_ringbuf_rec_pg_off(rb, hdr); 364457f4436SAndrii Nakryiko hdr->len = size | BPF_RINGBUF_BUSY_BIT; 365457f4436SAndrii Nakryiko hdr->pg_off = pg_off; 366457f4436SAndrii Nakryiko 367457f4436SAndrii Nakryiko /* pairs with consumer's smp_load_acquire() */ 368457f4436SAndrii Nakryiko smp_store_release(&rb->producer_pos, new_prod_pos); 369457f4436SAndrii Nakryiko 370457f4436SAndrii Nakryiko spin_unlock_irqrestore(&rb->spinlock, flags); 371457f4436SAndrii Nakryiko 372457f4436SAndrii Nakryiko return (void *)hdr + BPF_RINGBUF_HDR_SZ; 373457f4436SAndrii Nakryiko } 374457f4436SAndrii Nakryiko 375457f4436SAndrii Nakryiko BPF_CALL_3(bpf_ringbuf_reserve, struct bpf_map *, map, u64, size, u64, flags) 376457f4436SAndrii Nakryiko { 377457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 378457f4436SAndrii Nakryiko 379457f4436SAndrii Nakryiko if (unlikely(flags)) 380457f4436SAndrii Nakryiko return 0; 381457f4436SAndrii Nakryiko 382457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 383457f4436SAndrii Nakryiko return (unsigned long)__bpf_ringbuf_reserve(rb_map->rb, size); 384457f4436SAndrii Nakryiko } 385457f4436SAndrii Nakryiko 386457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_reserve_proto = { 387457f4436SAndrii Nakryiko .func = bpf_ringbuf_reserve, 388457f4436SAndrii Nakryiko .ret_type = RET_PTR_TO_ALLOC_MEM_OR_NULL, 389457f4436SAndrii Nakryiko .arg1_type = ARG_CONST_MAP_PTR, 390457f4436SAndrii Nakryiko .arg2_type = ARG_CONST_ALLOC_SIZE_OR_ZERO, 391457f4436SAndrii Nakryiko .arg3_type = ARG_ANYTHING, 392457f4436SAndrii Nakryiko }; 393457f4436SAndrii Nakryiko 394457f4436SAndrii Nakryiko static void bpf_ringbuf_commit(void *sample, u64 flags, bool discard) 395457f4436SAndrii Nakryiko { 396457f4436SAndrii Nakryiko unsigned long rec_pos, cons_pos; 397457f4436SAndrii Nakryiko struct bpf_ringbuf_hdr *hdr; 398457f4436SAndrii Nakryiko struct bpf_ringbuf *rb; 399457f4436SAndrii Nakryiko u32 new_len; 400457f4436SAndrii Nakryiko 401457f4436SAndrii Nakryiko hdr = sample - BPF_RINGBUF_HDR_SZ; 402457f4436SAndrii Nakryiko rb = bpf_ringbuf_restore_from_rec(hdr); 403457f4436SAndrii Nakryiko new_len = hdr->len ^ BPF_RINGBUF_BUSY_BIT; 404457f4436SAndrii Nakryiko if (discard) 405457f4436SAndrii Nakryiko new_len |= BPF_RINGBUF_DISCARD_BIT; 406457f4436SAndrii Nakryiko 407457f4436SAndrii Nakryiko /* update record header with correct final size prefix */ 408457f4436SAndrii Nakryiko xchg(&hdr->len, new_len); 409457f4436SAndrii Nakryiko 410457f4436SAndrii Nakryiko /* if consumer caught up and is waiting for our record, notify about 411457f4436SAndrii Nakryiko * new data availability 412457f4436SAndrii Nakryiko */ 413457f4436SAndrii Nakryiko rec_pos = (void *)hdr - (void *)rb->data; 414457f4436SAndrii Nakryiko cons_pos = smp_load_acquire(&rb->consumer_pos) & rb->mask; 415457f4436SAndrii Nakryiko 416457f4436SAndrii Nakryiko if (flags & BPF_RB_FORCE_WAKEUP) 417457f4436SAndrii Nakryiko irq_work_queue(&rb->work); 418457f4436SAndrii Nakryiko else if (cons_pos == rec_pos && !(flags & BPF_RB_NO_WAKEUP)) 419457f4436SAndrii Nakryiko irq_work_queue(&rb->work); 420457f4436SAndrii Nakryiko } 421457f4436SAndrii Nakryiko 422457f4436SAndrii Nakryiko BPF_CALL_2(bpf_ringbuf_submit, void *, sample, u64, flags) 423457f4436SAndrii Nakryiko { 424457f4436SAndrii Nakryiko bpf_ringbuf_commit(sample, flags, false /* discard */); 425457f4436SAndrii Nakryiko return 0; 426457f4436SAndrii Nakryiko } 427457f4436SAndrii Nakryiko 428457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_submit_proto = { 429457f4436SAndrii Nakryiko .func = bpf_ringbuf_submit, 430457f4436SAndrii Nakryiko .ret_type = RET_VOID, 431457f4436SAndrii Nakryiko .arg1_type = ARG_PTR_TO_ALLOC_MEM, 432457f4436SAndrii Nakryiko .arg2_type = ARG_ANYTHING, 433457f4436SAndrii Nakryiko }; 434457f4436SAndrii Nakryiko 435457f4436SAndrii Nakryiko BPF_CALL_2(bpf_ringbuf_discard, void *, sample, u64, flags) 436457f4436SAndrii Nakryiko { 437457f4436SAndrii Nakryiko bpf_ringbuf_commit(sample, flags, true /* discard */); 438457f4436SAndrii Nakryiko return 0; 439457f4436SAndrii Nakryiko } 440457f4436SAndrii Nakryiko 441457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_discard_proto = { 442457f4436SAndrii Nakryiko .func = bpf_ringbuf_discard, 443457f4436SAndrii Nakryiko .ret_type = RET_VOID, 444457f4436SAndrii Nakryiko .arg1_type = ARG_PTR_TO_ALLOC_MEM, 445457f4436SAndrii Nakryiko .arg2_type = ARG_ANYTHING, 446457f4436SAndrii Nakryiko }; 447457f4436SAndrii Nakryiko 448457f4436SAndrii Nakryiko BPF_CALL_4(bpf_ringbuf_output, struct bpf_map *, map, void *, data, u64, size, 449457f4436SAndrii Nakryiko u64, flags) 450457f4436SAndrii Nakryiko { 451457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 452457f4436SAndrii Nakryiko void *rec; 453457f4436SAndrii Nakryiko 454457f4436SAndrii Nakryiko if (unlikely(flags & ~(BPF_RB_NO_WAKEUP | BPF_RB_FORCE_WAKEUP))) 455457f4436SAndrii Nakryiko return -EINVAL; 456457f4436SAndrii Nakryiko 457457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 458457f4436SAndrii Nakryiko rec = __bpf_ringbuf_reserve(rb_map->rb, size); 459457f4436SAndrii Nakryiko if (!rec) 460457f4436SAndrii Nakryiko return -EAGAIN; 461457f4436SAndrii Nakryiko 462457f4436SAndrii Nakryiko memcpy(rec, data, size); 463457f4436SAndrii Nakryiko bpf_ringbuf_commit(rec, flags, false /* discard */); 464457f4436SAndrii Nakryiko return 0; 465457f4436SAndrii Nakryiko } 466457f4436SAndrii Nakryiko 467457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_output_proto = { 468457f4436SAndrii Nakryiko .func = bpf_ringbuf_output, 469457f4436SAndrii Nakryiko .ret_type = RET_INTEGER, 470457f4436SAndrii Nakryiko .arg1_type = ARG_CONST_MAP_PTR, 471457f4436SAndrii Nakryiko .arg2_type = ARG_PTR_TO_MEM, 472457f4436SAndrii Nakryiko .arg3_type = ARG_CONST_SIZE_OR_ZERO, 473457f4436SAndrii Nakryiko .arg4_type = ARG_ANYTHING, 474457f4436SAndrii Nakryiko }; 475457f4436SAndrii Nakryiko 476457f4436SAndrii Nakryiko BPF_CALL_2(bpf_ringbuf_query, struct bpf_map *, map, u64, flags) 477457f4436SAndrii Nakryiko { 478457f4436SAndrii Nakryiko struct bpf_ringbuf *rb; 479457f4436SAndrii Nakryiko 480457f4436SAndrii Nakryiko rb = container_of(map, struct bpf_ringbuf_map, map)->rb; 481457f4436SAndrii Nakryiko 482457f4436SAndrii Nakryiko switch (flags) { 483457f4436SAndrii Nakryiko case BPF_RB_AVAIL_DATA: 484457f4436SAndrii Nakryiko return ringbuf_avail_data_sz(rb); 485457f4436SAndrii Nakryiko case BPF_RB_RING_SIZE: 486457f4436SAndrii Nakryiko return rb->mask + 1; 487457f4436SAndrii Nakryiko case BPF_RB_CONS_POS: 488457f4436SAndrii Nakryiko return smp_load_acquire(&rb->consumer_pos); 489457f4436SAndrii Nakryiko case BPF_RB_PROD_POS: 490457f4436SAndrii Nakryiko return smp_load_acquire(&rb->producer_pos); 491457f4436SAndrii Nakryiko default: 492457f4436SAndrii Nakryiko return 0; 493457f4436SAndrii Nakryiko } 494457f4436SAndrii Nakryiko } 495457f4436SAndrii Nakryiko 496457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_query_proto = { 497457f4436SAndrii Nakryiko .func = bpf_ringbuf_query, 498457f4436SAndrii Nakryiko .ret_type = RET_INTEGER, 499457f4436SAndrii Nakryiko .arg1_type = ARG_CONST_MAP_PTR, 500457f4436SAndrii Nakryiko .arg2_type = ARG_ANYTHING, 501457f4436SAndrii Nakryiko }; 502