{	struct pt_regs *regs = (struct pt_regs *)(ctx->regs);	struct perf_event *event = ctx->event;	struct perf_callchain_entry *trace;	bool kernel, user;	int err = -EINVAL;	__u64 nr_kernel; 	if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))		return __bpf_get_stack(regs, NULL, NULL, buf, size, flags); 	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |			       BPF_F_USER_BUILD_ID)))		goto clear; 	user = flags & BPF_F_USER_STACK;	kernel = !user; 	err = -EFAULT;	trace = ctx->data->callchain;	if (unlikely(!trace))		goto clear; 	nr_kernel = count_kernel_ip(trace); 	if (kernel) {		__u64 nr = trace->nr; 		trace->nr = nr_kernel;		err = __bpf_get_stack(regs, NULL, trace, buf, size, flags); 		/* restore nr */		trace->nr = nr;	} else { /* user */		u64 skip = flags & BPF_F_SKIP_FIELD_MASK; 		skip += nr_kernel;		if (skip > BPF_F_SKIP_FIELD_MASK)			goto clear; 		flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip;		err = __bpf_get_stack(regs, NULL, trace, buf, size, flags);	}	return err; clear:	memset(buf, 0, size);	return err; } const struct bpf_func_proto bpf_get_stack_proto_pe = {	.func		= bpf_get_stack_pe,	.gpl_only	= true,	.ret_type	= RET_INTEGER,	.arg1_type	= ARG_PTR_TO_CTX,	.arg2_type	= ARG_PTR_TO_UNINIT_MEM,	.arg3_type	= ARG_CONST_SIZE_OR_ZERO,	.arg4_type	= ARG_ANYTHING,}; /* Called from eBPF program */static void *stack_map_lookup_elem(struct bpf_map *map, void *key){	return ERR_PTR(-EOPNOTSUPP);} /* Called from syscall */int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value){	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);	struct stack_map_bucket *bucket, *old_bucket;	u32 id = *(u32 *)key, trace_len; 	if (unlikely(id >= smap->n_buckets))		return -ENOENT; 	bucket = xchg(&smap->buckets[id], NULL);	if (!bucket)		return -ENOENT; 	trace_len = bucket->nr * stack_map_data_size(map);	memcpy(value, bucket->data, trace_len);	memset(value + trace_len, 0, map->value_size - trace_len); 	old_bucket = xchg(&smap->buckets[id], bucket);	if (old_bucket)		pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);	return 0;} static int stack_map_get_next_key(struct bpf_map *map, void *key,				  void *next_key){	struct bpf_stack_map *smap = container_of(map,						  struct bpf_stack_map, map);	u32 id; 	WARN_ON_ONCE(!rcu_read_lock_held()); 	if (!key) {		id = 0;	} else {		id = *(u32 *)key;		if (id >= smap->n_buckets || !smap->buckets[id])			id = 0;		else			id++;	} 	while (id < smap->n_buckets && !smap->buckets[id])		id++; 	if (id >= smap->n_buckets)		return -ENOENT; 	*(u32 *)next_key = id;	return 0;} static int stack_map_update_elem(struct bpf_map *map, void *key, void *value,				 u64 map_flags){	return -EINVAL;} /* Called from syscall or from eBPF program */static int stack_map_delete_elem(struct bpf_map *map, void *key){	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);	struct stack_map_bucket *old_bucket;	u32 id = *(u32 *)key; 	if (unlikely(id >= smap->n_buckets))		return -E2BIG; 	old_bucket = xchg(&smap->buckets[id], NULL);	if (old_bucket) {		pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);		return 0;	} else {		return -ENOENT;	}} /* Called when map->refcnt goes to zero, either from workqueue or from syscall */static void stack_map_free(struct bpf_map *map){	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 	bpf_map_area_free(smap->elems);	pcpu_freelist_destroy(&smap->freelist);	bpf_map_area_free(smap);	put_callchain_buffers();} BTF_ID_LIST_SINGLE(stack_trace_map_btf_ids, struct, bpf_stack_map)const struct bpf_map_ops stack_trace_map_ops = {	.map_meta_equal = bpf_map_meta_equal,	.map_alloc = stack_map_alloc,	.map_free = stack_map_free,	.map_get_next_key = stack_map_get_next_key,	.map_lookup_elem = stack_map_lookup_elem,	.map_update_elem = stack_map_update_elem,	.map_delete_elem = stack_map_delete_elem,	.map_check_btf = map_check_no_btf,	.map_btf_id = &stack_trace_map_btf_ids[0],};

Lines 501–668 of 668. Previous lines