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> 11ccff81e1SRustam Kovhaev #include <linux/kmemleak.h> 12457f4436SAndrii Nakryiko #include <uapi/linux/btf.h> 13457f4436SAndrii Nakryiko 14457f4436SAndrii Nakryiko #define RINGBUF_CREATE_FLAG_MASK (BPF_F_NUMA_NODE) 15457f4436SAndrii Nakryiko 16457f4436SAndrii Nakryiko /* non-mmap()'able part of bpf_ringbuf (everything up to consumer page) */ 17457f4436SAndrii Nakryiko #define RINGBUF_PGOFF \ 18457f4436SAndrii Nakryiko (offsetof(struct bpf_ringbuf, consumer_pos) >> PAGE_SHIFT) 19457f4436SAndrii Nakryiko /* consumer page and producer page */ 20457f4436SAndrii Nakryiko #define RINGBUF_POS_PAGES 2 21457f4436SAndrii Nakryiko 22457f4436SAndrii Nakryiko #define RINGBUF_MAX_RECORD_SZ (UINT_MAX/4) 23457f4436SAndrii Nakryiko 24457f4436SAndrii Nakryiko /* Maximum size of ring buffer area is limited by 32-bit page offset within 25457f4436SAndrii Nakryiko * record header, counted in pages. Reserve 8 bits for extensibility, and take 26457f4436SAndrii Nakryiko * into account few extra pages for consumer/producer pages and 27457f4436SAndrii Nakryiko * non-mmap()'able parts. This gives 64GB limit, which seems plenty for single 28457f4436SAndrii Nakryiko * ring buffer. 29457f4436SAndrii Nakryiko */ 30457f4436SAndrii Nakryiko #define RINGBUF_MAX_DATA_SZ \ 31457f4436SAndrii Nakryiko (((1ULL << 24) - RINGBUF_POS_PAGES - RINGBUF_PGOFF) * PAGE_SIZE) 32457f4436SAndrii Nakryiko 33457f4436SAndrii Nakryiko struct bpf_ringbuf { 34457f4436SAndrii Nakryiko wait_queue_head_t waitq; 35457f4436SAndrii Nakryiko struct irq_work work; 36457f4436SAndrii Nakryiko u64 mask; 37457f4436SAndrii Nakryiko struct page **pages; 38457f4436SAndrii Nakryiko int nr_pages; 39457f4436SAndrii Nakryiko spinlock_t spinlock ____cacheline_aligned_in_smp; 40457f4436SAndrii Nakryiko /* Consumer and producer counters are put into separate pages to allow 41457f4436SAndrii Nakryiko * mapping consumer page as r/w, but restrict producer page to r/o. 42457f4436SAndrii Nakryiko * This protects producer position from being modified by user-space 43457f4436SAndrii Nakryiko * application and ruining in-kernel position tracking. 44457f4436SAndrii Nakryiko */ 45457f4436SAndrii Nakryiko unsigned long consumer_pos __aligned(PAGE_SIZE); 46457f4436SAndrii Nakryiko unsigned long producer_pos __aligned(PAGE_SIZE); 47457f4436SAndrii Nakryiko char data[] __aligned(PAGE_SIZE); 48457f4436SAndrii Nakryiko }; 49457f4436SAndrii Nakryiko 50457f4436SAndrii Nakryiko struct bpf_ringbuf_map { 51457f4436SAndrii Nakryiko struct bpf_map map; 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 { 63be4035c7SRoman Gushchin const gfp_t flags = GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL | 64be4035c7SRoman Gushchin __GFP_NOWARN | __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); 91be4035c7SRoman Gushchin pages = bpf_map_area_alloc(array_size, numa_node); 92457f4436SAndrii Nakryiko if (!pages) 93457f4436SAndrii Nakryiko return NULL; 94457f4436SAndrii Nakryiko 95457f4436SAndrii Nakryiko for (i = 0; i < nr_pages; i++) { 96457f4436SAndrii Nakryiko page = alloc_pages_node(numa_node, flags, 0); 97457f4436SAndrii Nakryiko if (!page) { 98457f4436SAndrii Nakryiko nr_pages = i; 99457f4436SAndrii Nakryiko goto err_free_pages; 100457f4436SAndrii Nakryiko } 101457f4436SAndrii Nakryiko pages[i] = page; 102457f4436SAndrii Nakryiko if (i >= nr_meta_pages) 103457f4436SAndrii Nakryiko pages[nr_data_pages + i] = page; 104457f4436SAndrii Nakryiko } 105457f4436SAndrii Nakryiko 106457f4436SAndrii Nakryiko rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages, 107457f4436SAndrii Nakryiko VM_ALLOC | VM_USERMAP, PAGE_KERNEL); 108457f4436SAndrii Nakryiko if (rb) { 109ccff81e1SRustam Kovhaev kmemleak_not_leak(pages); 110457f4436SAndrii Nakryiko rb->pages = pages; 111457f4436SAndrii Nakryiko rb->nr_pages = nr_pages; 112457f4436SAndrii Nakryiko return rb; 113457f4436SAndrii Nakryiko } 114457f4436SAndrii Nakryiko 115457f4436SAndrii Nakryiko err_free_pages: 116457f4436SAndrii Nakryiko for (i = 0; i < nr_pages; i++) 117457f4436SAndrii Nakryiko __free_page(pages[i]); 118457f4436SAndrii Nakryiko kvfree(pages); 119457f4436SAndrii Nakryiko return NULL; 120457f4436SAndrii Nakryiko } 121457f4436SAndrii Nakryiko 122457f4436SAndrii Nakryiko static void bpf_ringbuf_notify(struct irq_work *work) 123457f4436SAndrii Nakryiko { 124457f4436SAndrii Nakryiko struct bpf_ringbuf *rb = container_of(work, struct bpf_ringbuf, work); 125457f4436SAndrii Nakryiko 126457f4436SAndrii Nakryiko wake_up_all(&rb->waitq); 127457f4436SAndrii Nakryiko } 128457f4436SAndrii Nakryiko 129457f4436SAndrii Nakryiko static struct bpf_ringbuf *bpf_ringbuf_alloc(size_t data_sz, int numa_node) 130457f4436SAndrii Nakryiko { 131457f4436SAndrii Nakryiko struct bpf_ringbuf *rb; 132457f4436SAndrii Nakryiko 133457f4436SAndrii Nakryiko rb = bpf_ringbuf_area_alloc(data_sz, numa_node); 134457f4436SAndrii Nakryiko if (!rb) 135abbdd081SRoman Gushchin return NULL; 136457f4436SAndrii Nakryiko 137457f4436SAndrii Nakryiko spin_lock_init(&rb->spinlock); 138457f4436SAndrii Nakryiko init_waitqueue_head(&rb->waitq); 139457f4436SAndrii Nakryiko init_irq_work(&rb->work, bpf_ringbuf_notify); 140457f4436SAndrii Nakryiko 141457f4436SAndrii Nakryiko rb->mask = data_sz - 1; 142457f4436SAndrii Nakryiko rb->consumer_pos = 0; 143457f4436SAndrii Nakryiko rb->producer_pos = 0; 144457f4436SAndrii Nakryiko 145457f4436SAndrii Nakryiko return rb; 146457f4436SAndrii Nakryiko } 147457f4436SAndrii Nakryiko 148457f4436SAndrii Nakryiko static struct bpf_map *ringbuf_map_alloc(union bpf_attr *attr) 149457f4436SAndrii Nakryiko { 150457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 151457f4436SAndrii Nakryiko 152457f4436SAndrii Nakryiko if (attr->map_flags & ~RINGBUF_CREATE_FLAG_MASK) 153457f4436SAndrii Nakryiko return ERR_PTR(-EINVAL); 154457f4436SAndrii Nakryiko 155457f4436SAndrii Nakryiko if (attr->key_size || attr->value_size || 156517bbe19SAndrii Nakryiko !is_power_of_2(attr->max_entries) || 157517bbe19SAndrii Nakryiko !PAGE_ALIGNED(attr->max_entries)) 158457f4436SAndrii Nakryiko return ERR_PTR(-EINVAL); 159457f4436SAndrii Nakryiko 160517bbe19SAndrii Nakryiko #ifdef CONFIG_64BIT 161517bbe19SAndrii Nakryiko /* on 32-bit arch, it's impossible to overflow record's hdr->pgoff */ 162517bbe19SAndrii Nakryiko if (attr->max_entries > RINGBUF_MAX_DATA_SZ) 163517bbe19SAndrii Nakryiko return ERR_PTR(-E2BIG); 164517bbe19SAndrii Nakryiko #endif 165517bbe19SAndrii Nakryiko 166be4035c7SRoman Gushchin rb_map = kzalloc(sizeof(*rb_map), GFP_USER | __GFP_ACCOUNT); 167457f4436SAndrii Nakryiko if (!rb_map) 168457f4436SAndrii Nakryiko return ERR_PTR(-ENOMEM); 169457f4436SAndrii Nakryiko 170457f4436SAndrii Nakryiko bpf_map_init_from_attr(&rb_map->map, attr); 171457f4436SAndrii Nakryiko 172457f4436SAndrii Nakryiko rb_map->rb = bpf_ringbuf_alloc(attr->max_entries, rb_map->map.numa_node); 173abbdd081SRoman Gushchin if (!rb_map->rb) { 174abbdd081SRoman Gushchin kfree(rb_map); 175abbdd081SRoman Gushchin return ERR_PTR(-ENOMEM); 176457f4436SAndrii Nakryiko } 177457f4436SAndrii Nakryiko 178457f4436SAndrii Nakryiko return &rb_map->map; 179457f4436SAndrii Nakryiko } 180457f4436SAndrii Nakryiko 181457f4436SAndrii Nakryiko static void bpf_ringbuf_free(struct bpf_ringbuf *rb) 182457f4436SAndrii Nakryiko { 183457f4436SAndrii Nakryiko /* copy pages pointer and nr_pages to local variable, as we are going 184457f4436SAndrii Nakryiko * to unmap rb itself with vunmap() below 185457f4436SAndrii Nakryiko */ 186457f4436SAndrii Nakryiko struct page **pages = rb->pages; 187457f4436SAndrii Nakryiko int i, nr_pages = rb->nr_pages; 188457f4436SAndrii Nakryiko 189457f4436SAndrii Nakryiko vunmap(rb); 190457f4436SAndrii Nakryiko for (i = 0; i < nr_pages; i++) 191457f4436SAndrii Nakryiko __free_page(pages[i]); 192457f4436SAndrii Nakryiko kvfree(pages); 193457f4436SAndrii Nakryiko } 194457f4436SAndrii Nakryiko 195457f4436SAndrii Nakryiko static void ringbuf_map_free(struct bpf_map *map) 196457f4436SAndrii Nakryiko { 197457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 198457f4436SAndrii Nakryiko 199457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 200457f4436SAndrii Nakryiko bpf_ringbuf_free(rb_map->rb); 201457f4436SAndrii Nakryiko kfree(rb_map); 202457f4436SAndrii Nakryiko } 203457f4436SAndrii Nakryiko 204457f4436SAndrii Nakryiko static void *ringbuf_map_lookup_elem(struct bpf_map *map, void *key) 205457f4436SAndrii Nakryiko { 206457f4436SAndrii Nakryiko return ERR_PTR(-ENOTSUPP); 207457f4436SAndrii Nakryiko } 208457f4436SAndrii Nakryiko 209457f4436SAndrii Nakryiko static int ringbuf_map_update_elem(struct bpf_map *map, void *key, void *value, 210457f4436SAndrii Nakryiko u64 flags) 211457f4436SAndrii Nakryiko { 212457f4436SAndrii Nakryiko return -ENOTSUPP; 213457f4436SAndrii Nakryiko } 214457f4436SAndrii Nakryiko 215457f4436SAndrii Nakryiko static int ringbuf_map_delete_elem(struct bpf_map *map, void *key) 216457f4436SAndrii Nakryiko { 217457f4436SAndrii Nakryiko return -ENOTSUPP; 218457f4436SAndrii Nakryiko } 219457f4436SAndrii Nakryiko 220457f4436SAndrii Nakryiko static int ringbuf_map_get_next_key(struct bpf_map *map, void *key, 221457f4436SAndrii Nakryiko void *next_key) 222457f4436SAndrii Nakryiko { 223457f4436SAndrii Nakryiko return -ENOTSUPP; 224457f4436SAndrii Nakryiko } 225457f4436SAndrii Nakryiko 226457f4436SAndrii Nakryiko static int ringbuf_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) 227457f4436SAndrii Nakryiko { 228457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 229457f4436SAndrii Nakryiko 230457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 231457f4436SAndrii Nakryiko 23204ea3086SAndrii Nakryiko if (vma->vm_flags & VM_WRITE) { 23304ea3086SAndrii Nakryiko /* allow writable mapping for the consumer_pos only */ 23404ea3086SAndrii Nakryiko if (vma->vm_pgoff != 0 || vma->vm_end - vma->vm_start != PAGE_SIZE) 23504ea3086SAndrii Nakryiko return -EPERM; 23604ea3086SAndrii Nakryiko } else { 23704ea3086SAndrii Nakryiko vma->vm_flags &= ~VM_MAYWRITE; 23804ea3086SAndrii Nakryiko } 23904ea3086SAndrii Nakryiko /* remap_vmalloc_range() checks size and offset constraints */ 240457f4436SAndrii Nakryiko return remap_vmalloc_range(vma, rb_map->rb, 241457f4436SAndrii Nakryiko vma->vm_pgoff + RINGBUF_PGOFF); 242457f4436SAndrii Nakryiko } 243457f4436SAndrii Nakryiko 244457f4436SAndrii Nakryiko static unsigned long ringbuf_avail_data_sz(struct bpf_ringbuf *rb) 245457f4436SAndrii Nakryiko { 246457f4436SAndrii Nakryiko unsigned long cons_pos, prod_pos; 247457f4436SAndrii Nakryiko 248457f4436SAndrii Nakryiko cons_pos = smp_load_acquire(&rb->consumer_pos); 249457f4436SAndrii Nakryiko prod_pos = smp_load_acquire(&rb->producer_pos); 250457f4436SAndrii Nakryiko return prod_pos - cons_pos; 251457f4436SAndrii Nakryiko } 252457f4436SAndrii Nakryiko 253457f4436SAndrii Nakryiko static __poll_t ringbuf_map_poll(struct bpf_map *map, struct file *filp, 254457f4436SAndrii Nakryiko struct poll_table_struct *pts) 255457f4436SAndrii Nakryiko { 256457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 257457f4436SAndrii Nakryiko 258457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 259457f4436SAndrii Nakryiko poll_wait(filp, &rb_map->rb->waitq, pts); 260457f4436SAndrii Nakryiko 261457f4436SAndrii Nakryiko if (ringbuf_avail_data_sz(rb_map->rb)) 262457f4436SAndrii Nakryiko return EPOLLIN | EPOLLRDNORM; 263457f4436SAndrii Nakryiko return 0; 264457f4436SAndrii Nakryiko } 265457f4436SAndrii Nakryiko 2662872e9acSAndrey Ignatov static int ringbuf_map_btf_id; 267457f4436SAndrii Nakryiko const struct bpf_map_ops ringbuf_map_ops = { 268f4d05259SMartin KaFai Lau .map_meta_equal = bpf_map_meta_equal, 269457f4436SAndrii Nakryiko .map_alloc = ringbuf_map_alloc, 270457f4436SAndrii Nakryiko .map_free = ringbuf_map_free, 271457f4436SAndrii Nakryiko .map_mmap = ringbuf_map_mmap, 272457f4436SAndrii Nakryiko .map_poll = ringbuf_map_poll, 273457f4436SAndrii Nakryiko .map_lookup_elem = ringbuf_map_lookup_elem, 274457f4436SAndrii Nakryiko .map_update_elem = ringbuf_map_update_elem, 275457f4436SAndrii Nakryiko .map_delete_elem = ringbuf_map_delete_elem, 276457f4436SAndrii Nakryiko .map_get_next_key = ringbuf_map_get_next_key, 2772872e9acSAndrey Ignatov .map_btf_name = "bpf_ringbuf_map", 2782872e9acSAndrey Ignatov .map_btf_id = &ringbuf_map_btf_id, 279457f4436SAndrii Nakryiko }; 280457f4436SAndrii Nakryiko 281457f4436SAndrii Nakryiko /* Given pointer to ring buffer record metadata and struct bpf_ringbuf itself, 282457f4436SAndrii Nakryiko * calculate offset from record metadata to ring buffer in pages, rounded 283457f4436SAndrii Nakryiko * down. This page offset is stored as part of record metadata and allows to 284457f4436SAndrii Nakryiko * restore struct bpf_ringbuf * from record pointer. This page offset is 285457f4436SAndrii Nakryiko * stored at offset 4 of record metadata header. 286457f4436SAndrii Nakryiko */ 287457f4436SAndrii Nakryiko static size_t bpf_ringbuf_rec_pg_off(struct bpf_ringbuf *rb, 288457f4436SAndrii Nakryiko struct bpf_ringbuf_hdr *hdr) 289457f4436SAndrii Nakryiko { 290457f4436SAndrii Nakryiko return ((void *)hdr - (void *)rb) >> PAGE_SHIFT; 291457f4436SAndrii Nakryiko } 292457f4436SAndrii Nakryiko 293457f4436SAndrii Nakryiko /* Given pointer to ring buffer record header, restore pointer to struct 294457f4436SAndrii Nakryiko * bpf_ringbuf itself by using page offset stored at offset 4 295457f4436SAndrii Nakryiko */ 296457f4436SAndrii Nakryiko static struct bpf_ringbuf * 297457f4436SAndrii Nakryiko bpf_ringbuf_restore_from_rec(struct bpf_ringbuf_hdr *hdr) 298457f4436SAndrii Nakryiko { 299457f4436SAndrii Nakryiko unsigned long addr = (unsigned long)(void *)hdr; 300457f4436SAndrii Nakryiko unsigned long off = (unsigned long)hdr->pg_off << PAGE_SHIFT; 301457f4436SAndrii Nakryiko 302457f4436SAndrii Nakryiko return (void*)((addr & PAGE_MASK) - off); 303457f4436SAndrii Nakryiko } 304457f4436SAndrii Nakryiko 305457f4436SAndrii Nakryiko static void *__bpf_ringbuf_reserve(struct bpf_ringbuf *rb, u64 size) 306457f4436SAndrii Nakryiko { 307457f4436SAndrii Nakryiko unsigned long cons_pos, prod_pos, new_prod_pos, flags; 308457f4436SAndrii Nakryiko u32 len, pg_off; 309457f4436SAndrii Nakryiko struct bpf_ringbuf_hdr *hdr; 310457f4436SAndrii Nakryiko 311457f4436SAndrii Nakryiko if (unlikely(size > RINGBUF_MAX_RECORD_SZ)) 312457f4436SAndrii Nakryiko return NULL; 313457f4436SAndrii Nakryiko 314457f4436SAndrii Nakryiko len = round_up(size + BPF_RINGBUF_HDR_SZ, 8); 3154b81ccebSThadeu Lima de Souza Cascardo if (len > rb->mask + 1) 3164b81ccebSThadeu Lima de Souza Cascardo return NULL; 3174b81ccebSThadeu Lima de Souza Cascardo 318457f4436SAndrii Nakryiko cons_pos = smp_load_acquire(&rb->consumer_pos); 319457f4436SAndrii Nakryiko 320457f4436SAndrii Nakryiko if (in_nmi()) { 321457f4436SAndrii Nakryiko if (!spin_trylock_irqsave(&rb->spinlock, flags)) 322457f4436SAndrii Nakryiko return NULL; 323457f4436SAndrii Nakryiko } else { 324457f4436SAndrii Nakryiko spin_lock_irqsave(&rb->spinlock, flags); 325457f4436SAndrii Nakryiko } 326457f4436SAndrii Nakryiko 327457f4436SAndrii Nakryiko prod_pos = rb->producer_pos; 328457f4436SAndrii Nakryiko new_prod_pos = prod_pos + len; 329457f4436SAndrii Nakryiko 330457f4436SAndrii Nakryiko /* check for out of ringbuf space by ensuring producer position 331457f4436SAndrii Nakryiko * doesn't advance more than (ringbuf_size - 1) ahead 332457f4436SAndrii Nakryiko */ 333457f4436SAndrii Nakryiko if (new_prod_pos - cons_pos > rb->mask) { 334457f4436SAndrii Nakryiko spin_unlock_irqrestore(&rb->spinlock, flags); 335457f4436SAndrii Nakryiko return NULL; 336457f4436SAndrii Nakryiko } 337457f4436SAndrii Nakryiko 338457f4436SAndrii Nakryiko hdr = (void *)rb->data + (prod_pos & rb->mask); 339457f4436SAndrii Nakryiko pg_off = bpf_ringbuf_rec_pg_off(rb, hdr); 340457f4436SAndrii Nakryiko hdr->len = size | BPF_RINGBUF_BUSY_BIT; 341457f4436SAndrii Nakryiko hdr->pg_off = pg_off; 342457f4436SAndrii Nakryiko 343457f4436SAndrii Nakryiko /* pairs with consumer's smp_load_acquire() */ 344457f4436SAndrii Nakryiko smp_store_release(&rb->producer_pos, new_prod_pos); 345457f4436SAndrii Nakryiko 346457f4436SAndrii Nakryiko spin_unlock_irqrestore(&rb->spinlock, flags); 347457f4436SAndrii Nakryiko 348457f4436SAndrii Nakryiko return (void *)hdr + BPF_RINGBUF_HDR_SZ; 349457f4436SAndrii Nakryiko } 350457f4436SAndrii Nakryiko 351457f4436SAndrii Nakryiko BPF_CALL_3(bpf_ringbuf_reserve, struct bpf_map *, map, u64, size, u64, flags) 352457f4436SAndrii Nakryiko { 353457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 354457f4436SAndrii Nakryiko 355457f4436SAndrii Nakryiko if (unlikely(flags)) 356457f4436SAndrii Nakryiko return 0; 357457f4436SAndrii Nakryiko 358457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 359457f4436SAndrii Nakryiko return (unsigned long)__bpf_ringbuf_reserve(rb_map->rb, size); 360457f4436SAndrii Nakryiko } 361457f4436SAndrii Nakryiko 362457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_reserve_proto = { 363457f4436SAndrii Nakryiko .func = bpf_ringbuf_reserve, 364457f4436SAndrii Nakryiko .ret_type = RET_PTR_TO_ALLOC_MEM_OR_NULL, 365457f4436SAndrii Nakryiko .arg1_type = ARG_CONST_MAP_PTR, 366457f4436SAndrii Nakryiko .arg2_type = ARG_CONST_ALLOC_SIZE_OR_ZERO, 367457f4436SAndrii Nakryiko .arg3_type = ARG_ANYTHING, 368457f4436SAndrii Nakryiko }; 369457f4436SAndrii Nakryiko 370457f4436SAndrii Nakryiko static void bpf_ringbuf_commit(void *sample, u64 flags, bool discard) 371457f4436SAndrii Nakryiko { 372457f4436SAndrii Nakryiko unsigned long rec_pos, cons_pos; 373457f4436SAndrii Nakryiko struct bpf_ringbuf_hdr *hdr; 374457f4436SAndrii Nakryiko struct bpf_ringbuf *rb; 375457f4436SAndrii Nakryiko u32 new_len; 376457f4436SAndrii Nakryiko 377457f4436SAndrii Nakryiko hdr = sample - BPF_RINGBUF_HDR_SZ; 378457f4436SAndrii Nakryiko rb = bpf_ringbuf_restore_from_rec(hdr); 379457f4436SAndrii Nakryiko new_len = hdr->len ^ BPF_RINGBUF_BUSY_BIT; 380457f4436SAndrii Nakryiko if (discard) 381457f4436SAndrii Nakryiko new_len |= BPF_RINGBUF_DISCARD_BIT; 382457f4436SAndrii Nakryiko 383457f4436SAndrii Nakryiko /* update record header with correct final size prefix */ 384457f4436SAndrii Nakryiko xchg(&hdr->len, new_len); 385457f4436SAndrii Nakryiko 386457f4436SAndrii Nakryiko /* if consumer caught up and is waiting for our record, notify about 387457f4436SAndrii Nakryiko * new data availability 388457f4436SAndrii Nakryiko */ 389457f4436SAndrii Nakryiko rec_pos = (void *)hdr - (void *)rb->data; 390457f4436SAndrii Nakryiko cons_pos = smp_load_acquire(&rb->consumer_pos) & rb->mask; 391457f4436SAndrii Nakryiko 392457f4436SAndrii Nakryiko if (flags & BPF_RB_FORCE_WAKEUP) 393457f4436SAndrii Nakryiko irq_work_queue(&rb->work); 394457f4436SAndrii Nakryiko else if (cons_pos == rec_pos && !(flags & BPF_RB_NO_WAKEUP)) 395457f4436SAndrii Nakryiko irq_work_queue(&rb->work); 396457f4436SAndrii Nakryiko } 397457f4436SAndrii Nakryiko 398457f4436SAndrii Nakryiko BPF_CALL_2(bpf_ringbuf_submit, void *, sample, u64, flags) 399457f4436SAndrii Nakryiko { 400457f4436SAndrii Nakryiko bpf_ringbuf_commit(sample, flags, false /* discard */); 401457f4436SAndrii Nakryiko return 0; 402457f4436SAndrii Nakryiko } 403457f4436SAndrii Nakryiko 404457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_submit_proto = { 405457f4436SAndrii Nakryiko .func = bpf_ringbuf_submit, 406457f4436SAndrii Nakryiko .ret_type = RET_VOID, 407457f4436SAndrii Nakryiko .arg1_type = ARG_PTR_TO_ALLOC_MEM, 408457f4436SAndrii Nakryiko .arg2_type = ARG_ANYTHING, 409457f4436SAndrii Nakryiko }; 410457f4436SAndrii Nakryiko 411457f4436SAndrii Nakryiko BPF_CALL_2(bpf_ringbuf_discard, void *, sample, u64, flags) 412457f4436SAndrii Nakryiko { 413457f4436SAndrii Nakryiko bpf_ringbuf_commit(sample, flags, true /* discard */); 414457f4436SAndrii Nakryiko return 0; 415457f4436SAndrii Nakryiko } 416457f4436SAndrii Nakryiko 417457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_discard_proto = { 418457f4436SAndrii Nakryiko .func = bpf_ringbuf_discard, 419457f4436SAndrii Nakryiko .ret_type = RET_VOID, 420457f4436SAndrii Nakryiko .arg1_type = ARG_PTR_TO_ALLOC_MEM, 421457f4436SAndrii Nakryiko .arg2_type = ARG_ANYTHING, 422457f4436SAndrii Nakryiko }; 423457f4436SAndrii Nakryiko 424457f4436SAndrii Nakryiko BPF_CALL_4(bpf_ringbuf_output, struct bpf_map *, map, void *, data, u64, size, 425457f4436SAndrii Nakryiko u64, flags) 426457f4436SAndrii Nakryiko { 427457f4436SAndrii Nakryiko struct bpf_ringbuf_map *rb_map; 428457f4436SAndrii Nakryiko void *rec; 429457f4436SAndrii Nakryiko 430457f4436SAndrii Nakryiko if (unlikely(flags & ~(BPF_RB_NO_WAKEUP | BPF_RB_FORCE_WAKEUP))) 431457f4436SAndrii Nakryiko return -EINVAL; 432457f4436SAndrii Nakryiko 433457f4436SAndrii Nakryiko rb_map = container_of(map, struct bpf_ringbuf_map, map); 434457f4436SAndrii Nakryiko rec = __bpf_ringbuf_reserve(rb_map->rb, size); 435457f4436SAndrii Nakryiko if (!rec) 436457f4436SAndrii Nakryiko return -EAGAIN; 437457f4436SAndrii Nakryiko 438457f4436SAndrii Nakryiko memcpy(rec, data, size); 439457f4436SAndrii Nakryiko bpf_ringbuf_commit(rec, flags, false /* discard */); 440457f4436SAndrii Nakryiko return 0; 441457f4436SAndrii Nakryiko } 442457f4436SAndrii Nakryiko 443457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_output_proto = { 444457f4436SAndrii Nakryiko .func = bpf_ringbuf_output, 445457f4436SAndrii Nakryiko .ret_type = RET_INTEGER, 446457f4436SAndrii Nakryiko .arg1_type = ARG_CONST_MAP_PTR, 447*216e3cd2SHao Luo .arg2_type = ARG_PTR_TO_MEM | MEM_RDONLY, 448457f4436SAndrii Nakryiko .arg3_type = ARG_CONST_SIZE_OR_ZERO, 449457f4436SAndrii Nakryiko .arg4_type = ARG_ANYTHING, 450457f4436SAndrii Nakryiko }; 451457f4436SAndrii Nakryiko 452457f4436SAndrii Nakryiko BPF_CALL_2(bpf_ringbuf_query, struct bpf_map *, map, u64, flags) 453457f4436SAndrii Nakryiko { 454457f4436SAndrii Nakryiko struct bpf_ringbuf *rb; 455457f4436SAndrii Nakryiko 456457f4436SAndrii Nakryiko rb = container_of(map, struct bpf_ringbuf_map, map)->rb; 457457f4436SAndrii Nakryiko 458457f4436SAndrii Nakryiko switch (flags) { 459457f4436SAndrii Nakryiko case BPF_RB_AVAIL_DATA: 460457f4436SAndrii Nakryiko return ringbuf_avail_data_sz(rb); 461457f4436SAndrii Nakryiko case BPF_RB_RING_SIZE: 462457f4436SAndrii Nakryiko return rb->mask + 1; 463457f4436SAndrii Nakryiko case BPF_RB_CONS_POS: 464457f4436SAndrii Nakryiko return smp_load_acquire(&rb->consumer_pos); 465457f4436SAndrii Nakryiko case BPF_RB_PROD_POS: 466457f4436SAndrii Nakryiko return smp_load_acquire(&rb->producer_pos); 467457f4436SAndrii Nakryiko default: 468457f4436SAndrii Nakryiko return 0; 469457f4436SAndrii Nakryiko } 470457f4436SAndrii Nakryiko } 471457f4436SAndrii Nakryiko 472457f4436SAndrii Nakryiko const struct bpf_func_proto bpf_ringbuf_query_proto = { 473457f4436SAndrii Nakryiko .func = bpf_ringbuf_query, 474457f4436SAndrii Nakryiko .ret_type = RET_INTEGER, 475457f4436SAndrii Nakryiko .arg1_type = ARG_CONST_MAP_PTR, 476457f4436SAndrii Nakryiko .arg2_type = ARG_ANYTHING, 477457f4436SAndrii Nakryiko }; 478