diff options
Diffstat (limited to 'kernel/bpf/bpf_iter.c')
| -rw-r--r-- | kernel/bpf/bpf_iter.c | 112 |
1 files changed, 87 insertions, 25 deletions
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index b2ee45064e06..5dc307bdeaeb 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -5,6 +5,7 @@ #include <linux/anon_inodes.h> #include <linux/filter.h> #include <linux/bpf.h> +#include <linux/rcupdate_trace.h> struct bpf_iter_target_info { struct list_head list; @@ -67,23 +68,27 @@ static void bpf_iter_done_stop(struct seq_file *seq) iter_priv->done_stop = true; } +static inline bool bpf_iter_target_support_resched(const struct bpf_iter_target_info *tinfo) +{ + return tinfo->reg_info->feature & BPF_ITER_RESCHED; +} + static bool bpf_iter_support_resched(struct seq_file *seq) { struct bpf_iter_priv_data *iter_priv; iter_priv = container_of(seq->private, struct bpf_iter_priv_data, target_private); - return iter_priv->tinfo->reg_info->feature & BPF_ITER_RESCHED; + return bpf_iter_target_support_resched(iter_priv->tinfo); } /* maximum visited objects before bailing out */ #define MAX_ITER_OBJECTS 1000000 /* bpf_seq_read, a customized and simpler version for bpf iterator. - * no_llseek is assumed for this file. * The following are differences from seq_read(): * . fixed buffer size (PAGE_SIZE) - * . assuming no_llseek + * . assuming NULL ->llseek() * . stop() may call bpf program, handling potential overflow there */ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size, @@ -197,6 +202,11 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size, } stop: offs = seq->count; + if (IS_ERR(p)) { + seq->op->stop(seq, NULL); + err = PTR_ERR(p); + goto done; + } /* bpf program called if !p */ seq->op->stop(seq, p); if (!p) { @@ -329,35 +339,34 @@ static void cache_btf_id(struct bpf_iter_target_info *tinfo, bool bpf_iter_prog_supported(struct bpf_prog *prog) { const char *attach_fname = prog->aux->attach_func_name; + struct bpf_iter_target_info *tinfo = NULL, *iter; u32 prog_btf_id = prog->aux->attach_btf_id; const char *prefix = BPF_ITER_FUNC_PREFIX; - struct bpf_iter_target_info *tinfo; int prefix_len = strlen(prefix); - bool supported = false; if (strncmp(attach_fname, prefix, prefix_len)) return false; mutex_lock(&targets_mutex); - list_for_each_entry(tinfo, &targets, list) { - if (tinfo->btf_id && tinfo->btf_id == prog_btf_id) { - supported = true; + list_for_each_entry(iter, &targets, list) { + if (iter->btf_id && iter->btf_id == prog_btf_id) { + tinfo = iter; break; } - if (!strcmp(attach_fname + prefix_len, tinfo->reg_info->target)) { - cache_btf_id(tinfo, prog); - supported = true; + if (!strcmp(attach_fname + prefix_len, iter->reg_info->target)) { + cache_btf_id(iter, prog); + tinfo = iter; break; } } mutex_unlock(&targets_mutex); - if (supported) { + if (tinfo) { prog->aux->ctx_arg_info_size = tinfo->reg_info->ctx_arg_info_size; prog->aux->ctx_arg_info = tinfo->reg_info->ctx_arg_info; } - return supported; + return tinfo != NULL; } const struct bpf_func_proto * @@ -498,12 +507,11 @@ bool bpf_link_is_iter(struct bpf_link *link) int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_prog *prog) { + struct bpf_iter_target_info *tinfo = NULL, *iter; struct bpf_link_primer link_primer; - struct bpf_iter_target_info *tinfo; union bpf_iter_link_info linfo; struct bpf_iter_link *link; u32 prog_btf_id, linfo_len; - bool existed = false; bpfptr_t ulinfo; int err; @@ -529,16 +537,20 @@ int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr, prog_btf_id = prog->aux->attach_btf_id; mutex_lock(&targets_mutex); - list_for_each_entry(tinfo, &targets, list) { - if (tinfo->btf_id == prog_btf_id) { - existed = true; + list_for_each_entry(iter, &targets, list) { + if (iter->btf_id == prog_btf_id) { + tinfo = iter; break; } } mutex_unlock(&targets_mutex); - if (!existed) + if (!tinfo) return -ENOENT; + /* Only allow sleepable program for resched-able iterator */ + if (prog->aux->sleepable && !bpf_iter_target_support_resched(tinfo)) + return -EINVAL; + link = kzalloc(sizeof(*link), GFP_USER | __GFP_NOWARN); if (!link) return -ENOMEM; @@ -546,7 +558,7 @@ int bpf_iter_link_attach(const union bpf_attr *attr, bpfptr_t uattr, bpf_link_init(&link->link, BPF_LINK_TYPE_ITER, &bpf_iter_link_lops, prog); link->tinfo = tinfo; - err = bpf_link_prime(&link->link, &link_primer); + err = bpf_link_prime(&link->link, &link_primer); if (err) { kfree(link); return err; @@ -682,13 +694,27 @@ struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop) int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx) { + struct bpf_run_ctx run_ctx, *old_run_ctx; int ret; - rcu_read_lock(); - migrate_disable(); - ret = bpf_prog_run(prog, ctx); - migrate_enable(); - rcu_read_unlock(); + if (prog->aux->sleepable) { + rcu_read_lock_trace(); + migrate_disable(); + might_fault(); + old_run_ctx = bpf_set_run_ctx(&run_ctx); + ret = bpf_prog_run(prog, ctx); + bpf_reset_run_ctx(old_run_ctx); + migrate_enable(); + rcu_read_unlock_trace(); + } else { + rcu_read_lock(); + migrate_disable(); + old_run_ctx = bpf_set_run_ctx(&run_ctx); + ret = bpf_prog_run(prog, ctx); + bpf_reset_run_ctx(old_run_ctx); + migrate_enable(); + rcu_read_unlock(); + } /* bpf program can only return 0 or 1: * 0 : okay @@ -714,3 +740,39 @@ const struct bpf_func_proto bpf_for_each_map_elem_proto = { .arg3_type = ARG_PTR_TO_STACK_OR_NULL, .arg4_type = ARG_ANYTHING, }; + +BPF_CALL_4(bpf_loop, u32, nr_loops, void *, callback_fn, void *, callback_ctx, + u64, flags) +{ + bpf_callback_t callback = (bpf_callback_t)callback_fn; + u64 ret; + u32 i; + + /* Note: these safety checks are also verified when bpf_loop + * is inlined, be careful to modify this code in sync. See + * function verifier.c:inline_bpf_loop. + */ + if (flags) + return -EINVAL; + if (nr_loops > BPF_MAX_LOOPS) + return -E2BIG; + + for (i = 0; i < nr_loops; i++) { + ret = callback((u64)i, (u64)(long)callback_ctx, 0, 0, 0); + /* return value: 0 - continue, 1 - stop and return */ + if (ret) + return i + 1; + } + + return i; +} + +const struct bpf_func_proto bpf_loop_proto = { + .func = bpf_loop, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_ANYTHING, + .arg2_type = ARG_PTR_TO_FUNC, + .arg3_type = ARG_PTR_TO_STACK_OR_NULL, + .arg4_type = ARG_ANYTHING, +}; |