Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c
new file mode 100644
index 0000000..1e4bf23
--- /dev/null
+++ b/kernel/bpf/ringbuf.c
@@ -0,0 +1,496 @@
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/err.h>
+#include <linux/irq_work.h>
+#include <linux/slab.h>
+#include <linux/filter.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/kmemleak.h>
+#include <uapi/linux/btf.h>
+
+#define RINGBUF_CREATE_FLAG_MASK (BPF_F_NUMA_NODE)
+
+/* non-mmap()'able part of bpf_ringbuf (everything up to consumer page) */
+#define RINGBUF_PGOFF \
+ (offsetof(struct bpf_ringbuf, consumer_pos) >> PAGE_SHIFT)
+/* consumer page and producer page */
+#define RINGBUF_POS_PAGES 2
+
+#define RINGBUF_MAX_RECORD_SZ (UINT_MAX/4)
+
+/* Maximum size of ring buffer area is limited by 32-bit page offset within
+ * record header, counted in pages. Reserve 8 bits for extensibility, and take
+ * into account few extra pages for consumer/producer pages and
+ * non-mmap()'able parts. This gives 64GB limit, which seems plenty for single
+ * ring buffer.
+ */
+#define RINGBUF_MAX_DATA_SZ \
+ (((1ULL << 24) - RINGBUF_POS_PAGES - RINGBUF_PGOFF) * PAGE_SIZE)
+
+struct bpf_ringbuf {
+ wait_queue_head_t waitq;
+ struct irq_work work;
+ u64 mask;
+ struct page **pages;
+ int nr_pages;
+ spinlock_t spinlock ____cacheline_aligned_in_smp;
+ /* Consumer and producer counters are put into separate pages to allow
+ * mapping consumer page as r/w, but restrict producer page to r/o.
+ * This protects producer position from being modified by user-space
+ * application and ruining in-kernel position tracking.
+ */
+ unsigned long consumer_pos __aligned(PAGE_SIZE);
+ unsigned long producer_pos __aligned(PAGE_SIZE);
+ char data[] __aligned(PAGE_SIZE);
+};
+
+struct bpf_ringbuf_map {
+ struct bpf_map map;
+ struct bpf_map_memory memory;
+ struct bpf_ringbuf *rb;
+};
+
+/* 8-byte ring buffer record header structure */
+struct bpf_ringbuf_hdr {
+ u32 len;
+ u32 pg_off;
+};
+
+static struct bpf_ringbuf *bpf_ringbuf_area_alloc(size_t data_sz, int numa_node)
+{
+ const gfp_t flags = GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN |
+ __GFP_ZERO;
+ int nr_meta_pages = RINGBUF_PGOFF + RINGBUF_POS_PAGES;
+ int nr_data_pages = data_sz >> PAGE_SHIFT;
+ int nr_pages = nr_meta_pages + nr_data_pages;
+ struct page **pages, *page;
+ struct bpf_ringbuf *rb;
+ size_t array_size;
+ int i;
+
+ /* Each data page is mapped twice to allow "virtual"
+ * continuous read of samples wrapping around the end of ring
+ * buffer area:
+ * ------------------------------------------------------
+ * | meta pages | real data pages | same data pages |
+ * ------------------------------------------------------
+ * | | 1 2 3 4 5 6 7 8 9 | 1 2 3 4 5 6 7 8 9 |
+ * ------------------------------------------------------
+ * | | TA DA | TA DA |
+ * ------------------------------------------------------
+ * ^^^^^^^
+ * |
+ * Here, no need to worry about special handling of wrapped-around
+ * data due to double-mapped data pages. This works both in kernel and
+ * when mmap()'ed in user-space, simplifying both kernel and
+ * user-space implementations significantly.
+ */
+ array_size = (nr_meta_pages + 2 * nr_data_pages) * sizeof(*pages);
+ if (array_size > PAGE_SIZE)
+ pages = vmalloc_node(array_size, numa_node);
+ else
+ pages = kmalloc_node(array_size, flags, numa_node);
+ if (!pages)
+ return NULL;
+
+ for (i = 0; i < nr_pages; i++) {
+ page = alloc_pages_node(numa_node, flags, 0);
+ if (!page) {
+ nr_pages = i;
+ goto err_free_pages;
+ }
+ pages[i] = page;
+ if (i >= nr_meta_pages)
+ pages[nr_data_pages + i] = page;
+ }
+
+ rb = vmap(pages, nr_meta_pages + 2 * nr_data_pages,
+ VM_MAP | VM_USERMAP, PAGE_KERNEL);
+ if (rb) {
+ kmemleak_not_leak(pages);
+ rb->pages = pages;
+ rb->nr_pages = nr_pages;
+ return rb;
+ }
+
+err_free_pages:
+ for (i = 0; i < nr_pages; i++)
+ __free_page(pages[i]);
+ kvfree(pages);
+ return NULL;
+}
+
+static void bpf_ringbuf_notify(struct irq_work *work)
+{
+ struct bpf_ringbuf *rb = container_of(work, struct bpf_ringbuf, work);
+
+ wake_up_all(&rb->waitq);
+}
+
+static struct bpf_ringbuf *bpf_ringbuf_alloc(size_t data_sz, int numa_node)
+{
+ struct bpf_ringbuf *rb;
+
+ rb = bpf_ringbuf_area_alloc(data_sz, numa_node);
+ if (!rb)
+ return ERR_PTR(-ENOMEM);
+
+ spin_lock_init(&rb->spinlock);
+ init_waitqueue_head(&rb->waitq);
+ init_irq_work(&rb->work, bpf_ringbuf_notify);
+
+ rb->mask = data_sz - 1;
+ rb->consumer_pos = 0;
+ rb->producer_pos = 0;
+
+ return rb;
+}
+
+static struct bpf_map *ringbuf_map_alloc(union bpf_attr *attr)
+{
+ struct bpf_ringbuf_map *rb_map;
+ u64 cost;
+ int err;
+
+ if (attr->map_flags & ~RINGBUF_CREATE_FLAG_MASK)
+ return ERR_PTR(-EINVAL);
+
+ if (attr->key_size || attr->value_size ||
+ !is_power_of_2(attr->max_entries) ||
+ !PAGE_ALIGNED(attr->max_entries))
+ return ERR_PTR(-EINVAL);
+
+#ifdef CONFIG_64BIT
+ /* on 32-bit arch, it's impossible to overflow record's hdr->pgoff */
+ if (attr->max_entries > RINGBUF_MAX_DATA_SZ)
+ return ERR_PTR(-E2BIG);
+#endif
+
+ rb_map = kzalloc(sizeof(*rb_map), GFP_USER);
+ if (!rb_map)
+ return ERR_PTR(-ENOMEM);
+
+ bpf_map_init_from_attr(&rb_map->map, attr);
+
+ cost = sizeof(struct bpf_ringbuf_map) +
+ sizeof(struct bpf_ringbuf) +
+ attr->max_entries;
+ err = bpf_map_charge_init(&rb_map->map.memory, cost);
+ if (err)
+ goto err_free_map;
+
+ rb_map->rb = bpf_ringbuf_alloc(attr->max_entries, rb_map->map.numa_node);
+ if (IS_ERR(rb_map->rb)) {
+ err = PTR_ERR(rb_map->rb);
+ goto err_uncharge;
+ }
+
+ return &rb_map->map;
+
+err_uncharge:
+ bpf_map_charge_finish(&rb_map->map.memory);
+err_free_map:
+ kfree(rb_map);
+ return ERR_PTR(err);
+}
+
+static void bpf_ringbuf_free(struct bpf_ringbuf *rb)
+{
+ /* copy pages pointer and nr_pages to local variable, as we are going
+ * to unmap rb itself with vunmap() below
+ */
+ struct page **pages = rb->pages;
+ int i, nr_pages = rb->nr_pages;
+
+ vunmap(rb);
+ for (i = 0; i < nr_pages; i++)
+ __free_page(pages[i]);
+ kvfree(pages);
+}
+
+static void ringbuf_map_free(struct bpf_map *map)
+{
+ struct bpf_ringbuf_map *rb_map;
+
+ rb_map = container_of(map, struct bpf_ringbuf_map, map);
+ bpf_ringbuf_free(rb_map->rb);
+ kfree(rb_map);
+}
+
+static void *ringbuf_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ return ERR_PTR(-ENOTSUPP);
+}
+
+static int ringbuf_map_update_elem(struct bpf_map *map, void *key, void *value,
+ u64 flags)
+{
+ return -ENOTSUPP;
+}
+
+static int ringbuf_map_delete_elem(struct bpf_map *map, void *key)
+{
+ return -ENOTSUPP;
+}
+
+static int ringbuf_map_get_next_key(struct bpf_map *map, void *key,
+ void *next_key)
+{
+ return -ENOTSUPP;
+}
+
+static int ringbuf_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
+{
+ struct bpf_ringbuf_map *rb_map;
+
+ rb_map = container_of(map, struct bpf_ringbuf_map, map);
+
+ if (vma->vm_flags & VM_WRITE) {
+ /* allow writable mapping for the consumer_pos only */
+ if (vma->vm_pgoff != 0 || vma->vm_end - vma->vm_start != PAGE_SIZE)
+ return -EPERM;
+ } else {
+ vma->vm_flags &= ~VM_MAYWRITE;
+ }
+ /* remap_vmalloc_range() checks size and offset constraints */
+ return remap_vmalloc_range(vma, rb_map->rb,
+ vma->vm_pgoff + RINGBUF_PGOFF);
+}
+
+static unsigned long ringbuf_avail_data_sz(struct bpf_ringbuf *rb)
+{
+ unsigned long cons_pos, prod_pos;
+
+ cons_pos = smp_load_acquire(&rb->consumer_pos);
+ prod_pos = smp_load_acquire(&rb->producer_pos);
+ return prod_pos - cons_pos;
+}
+
+static __poll_t ringbuf_map_poll(struct bpf_map *map, struct file *filp,
+ struct poll_table_struct *pts)
+{
+ struct bpf_ringbuf_map *rb_map;
+
+ rb_map = container_of(map, struct bpf_ringbuf_map, map);
+ poll_wait(filp, &rb_map->rb->waitq, pts);
+
+ if (ringbuf_avail_data_sz(rb_map->rb))
+ return EPOLLIN | EPOLLRDNORM;
+ return 0;
+}
+
+static int ringbuf_map_btf_id;
+const struct bpf_map_ops ringbuf_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
+ .map_alloc = ringbuf_map_alloc,
+ .map_free = ringbuf_map_free,
+ .map_mmap = ringbuf_map_mmap,
+ .map_poll = ringbuf_map_poll,
+ .map_lookup_elem = ringbuf_map_lookup_elem,
+ .map_update_elem = ringbuf_map_update_elem,
+ .map_delete_elem = ringbuf_map_delete_elem,
+ .map_get_next_key = ringbuf_map_get_next_key,
+ .map_btf_name = "bpf_ringbuf_map",
+ .map_btf_id = &ringbuf_map_btf_id,
+};
+
+/* Given pointer to ring buffer record metadata and struct bpf_ringbuf itself,
+ * calculate offset from record metadata to ring buffer in pages, rounded
+ * down. This page offset is stored as part of record metadata and allows to
+ * restore struct bpf_ringbuf * from record pointer. This page offset is
+ * stored at offset 4 of record metadata header.
+ */
+static size_t bpf_ringbuf_rec_pg_off(struct bpf_ringbuf *rb,
+ struct bpf_ringbuf_hdr *hdr)
+{
+ return ((void *)hdr - (void *)rb) >> PAGE_SHIFT;
+}
+
+/* Given pointer to ring buffer record header, restore pointer to struct
+ * bpf_ringbuf itself by using page offset stored at offset 4
+ */
+static struct bpf_ringbuf *
+bpf_ringbuf_restore_from_rec(struct bpf_ringbuf_hdr *hdr)
+{
+ unsigned long addr = (unsigned long)(void *)hdr;
+ unsigned long off = (unsigned long)hdr->pg_off << PAGE_SHIFT;
+
+ return (void*)((addr & PAGE_MASK) - off);
+}
+
+static void *__bpf_ringbuf_reserve(struct bpf_ringbuf *rb, u64 size)
+{
+ unsigned long cons_pos, prod_pos, new_prod_pos, flags;
+ u32 len, pg_off;
+ struct bpf_ringbuf_hdr *hdr;
+
+ if (unlikely(size > RINGBUF_MAX_RECORD_SZ))
+ return NULL;
+
+ len = round_up(size + BPF_RINGBUF_HDR_SZ, 8);
+ if (len > rb->mask + 1)
+ return NULL;
+
+ cons_pos = smp_load_acquire(&rb->consumer_pos);
+
+ if (in_nmi()) {
+ if (!spin_trylock_irqsave(&rb->spinlock, flags))
+ return NULL;
+ } else {
+ spin_lock_irqsave(&rb->spinlock, flags);
+ }
+
+ prod_pos = rb->producer_pos;
+ new_prod_pos = prod_pos + len;
+
+ /* check for out of ringbuf space by ensuring producer position
+ * doesn't advance more than (ringbuf_size - 1) ahead
+ */
+ if (new_prod_pos - cons_pos > rb->mask) {
+ spin_unlock_irqrestore(&rb->spinlock, flags);
+ return NULL;
+ }
+
+ hdr = (void *)rb->data + (prod_pos & rb->mask);
+ pg_off = bpf_ringbuf_rec_pg_off(rb, hdr);
+ hdr->len = size | BPF_RINGBUF_BUSY_BIT;
+ hdr->pg_off = pg_off;
+
+ /* pairs with consumer's smp_load_acquire() */
+ smp_store_release(&rb->producer_pos, new_prod_pos);
+
+ spin_unlock_irqrestore(&rb->spinlock, flags);
+
+ return (void *)hdr + BPF_RINGBUF_HDR_SZ;
+}
+
+BPF_CALL_3(bpf_ringbuf_reserve, struct bpf_map *, map, u64, size, u64, flags)
+{
+ struct bpf_ringbuf_map *rb_map;
+
+ if (unlikely(flags))
+ return 0;
+
+ rb_map = container_of(map, struct bpf_ringbuf_map, map);
+ return (unsigned long)__bpf_ringbuf_reserve(rb_map->rb, size);
+}
+
+const struct bpf_func_proto bpf_ringbuf_reserve_proto = {
+ .func = bpf_ringbuf_reserve,
+ .ret_type = RET_PTR_TO_ALLOC_MEM_OR_NULL,
+ .arg1_type = ARG_CONST_MAP_PTR,
+ .arg2_type = ARG_CONST_ALLOC_SIZE_OR_ZERO,
+ .arg3_type = ARG_ANYTHING,
+};
+
+static void bpf_ringbuf_commit(void *sample, u64 flags, bool discard)
+{
+ unsigned long rec_pos, cons_pos;
+ struct bpf_ringbuf_hdr *hdr;
+ struct bpf_ringbuf *rb;
+ u32 new_len;
+
+ hdr = sample - BPF_RINGBUF_HDR_SZ;
+ rb = bpf_ringbuf_restore_from_rec(hdr);
+ new_len = hdr->len ^ BPF_RINGBUF_BUSY_BIT;
+ if (discard)
+ new_len |= BPF_RINGBUF_DISCARD_BIT;
+
+ /* update record header with correct final size prefix */
+ xchg(&hdr->len, new_len);
+
+ /* if consumer caught up and is waiting for our record, notify about
+ * new data availability
+ */
+ rec_pos = (void *)hdr - (void *)rb->data;
+ cons_pos = smp_load_acquire(&rb->consumer_pos) & rb->mask;
+
+ if (flags & BPF_RB_FORCE_WAKEUP)
+ irq_work_queue(&rb->work);
+ else if (cons_pos == rec_pos && !(flags & BPF_RB_NO_WAKEUP))
+ irq_work_queue(&rb->work);
+}
+
+BPF_CALL_2(bpf_ringbuf_submit, void *, sample, u64, flags)
+{
+ bpf_ringbuf_commit(sample, flags, false /* discard */);
+ return 0;
+}
+
+const struct bpf_func_proto bpf_ringbuf_submit_proto = {
+ .func = bpf_ringbuf_submit,
+ .ret_type = RET_VOID,
+ .arg1_type = ARG_PTR_TO_ALLOC_MEM,
+ .arg2_type = ARG_ANYTHING,
+};
+
+BPF_CALL_2(bpf_ringbuf_discard, void *, sample, u64, flags)
+{
+ bpf_ringbuf_commit(sample, flags, true /* discard */);
+ return 0;
+}
+
+const struct bpf_func_proto bpf_ringbuf_discard_proto = {
+ .func = bpf_ringbuf_discard,
+ .ret_type = RET_VOID,
+ .arg1_type = ARG_PTR_TO_ALLOC_MEM,
+ .arg2_type = ARG_ANYTHING,
+};
+
+BPF_CALL_4(bpf_ringbuf_output, struct bpf_map *, map, void *, data, u64, size,
+ u64, flags)
+{
+ struct bpf_ringbuf_map *rb_map;
+ void *rec;
+
+ if (unlikely(flags & ~(BPF_RB_NO_WAKEUP | BPF_RB_FORCE_WAKEUP)))
+ return -EINVAL;
+
+ rb_map = container_of(map, struct bpf_ringbuf_map, map);
+ rec = __bpf_ringbuf_reserve(rb_map->rb, size);
+ if (!rec)
+ return -EAGAIN;
+
+ memcpy(rec, data, size);
+ bpf_ringbuf_commit(rec, flags, false /* discard */);
+ return 0;
+}
+
+const struct bpf_func_proto bpf_ringbuf_output_proto = {
+ .func = bpf_ringbuf_output,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_CONST_MAP_PTR,
+ .arg2_type = ARG_PTR_TO_MEM,
+ .arg3_type = ARG_CONST_SIZE_OR_ZERO,
+ .arg4_type = ARG_ANYTHING,
+};
+
+BPF_CALL_2(bpf_ringbuf_query, struct bpf_map *, map, u64, flags)
+{
+ struct bpf_ringbuf *rb;
+
+ rb = container_of(map, struct bpf_ringbuf_map, map)->rb;
+
+ switch (flags) {
+ case BPF_RB_AVAIL_DATA:
+ return ringbuf_avail_data_sz(rb);
+ case BPF_RB_RING_SIZE:
+ return rb->mask + 1;
+ case BPF_RB_CONS_POS:
+ return smp_load_acquire(&rb->consumer_pos);
+ case BPF_RB_PROD_POS:
+ return smp_load_acquire(&rb->producer_pos);
+ default:
+ return 0;
+ }
+}
+
+const struct bpf_func_proto bpf_ringbuf_query_proto = {
+ .func = bpf_ringbuf_query,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_CONST_MAP_PTR,
+ .arg2_type = ARG_ANYTHING,
+};