#include <linux/filter.h>
#include <linux/ftrace.h>
#include <linux/rbtree_latch.h>
+#include <linux/perf_event.h>
/* dummy _ops. The verifier will operate on target program's ops. */
const struct bpf_verifier_ops bpf_extension_verifier_ops = {
#define TRAMPOLINE_TABLE_SIZE (1 << TRAMPOLINE_HASH_BITS)
static struct hlist_head trampoline_table[TRAMPOLINE_TABLE_SIZE];
-static struct latch_tree_root image_tree __cacheline_aligned;
-/* serializes access to trampoline_table and image_tree */
+/* serializes access to trampoline_table */
static DEFINE_MUTEX(trampoline_mutex);
-static void *bpf_jit_alloc_exec_page(void)
+void *bpf_jit_alloc_exec_page(void)
{
void *image;
return image;
}
-static __always_inline bool image_tree_less(struct latch_tree_node *a,
- struct latch_tree_node *b)
+void bpf_image_ksym_add(void *data, struct bpf_ksym *ksym)
{
- struct bpf_image *ia = container_of(a, struct bpf_image, tnode);
- struct bpf_image *ib = container_of(b, struct bpf_image, tnode);
-
- return ia < ib;
-}
-
-static __always_inline int image_tree_comp(void *addr, struct latch_tree_node *n)
-{
- void *image = container_of(n, struct bpf_image, tnode);
-
- if (addr < image)
- return -1;
- if (addr >= image + PAGE_SIZE)
- return 1;
-
- return 0;
-}
-
-static const struct latch_tree_ops image_tree_ops = {
- .less = image_tree_less,
- .comp = image_tree_comp,
-};
-
-static void *__bpf_image_alloc(bool lock)
-{
- struct bpf_image *image;
-
- image = bpf_jit_alloc_exec_page();
- if (!image)
- return NULL;
-
- if (lock)
- mutex_lock(&trampoline_mutex);
- latch_tree_insert(&image->tnode, &image_tree, &image_tree_ops);
- if (lock)
- mutex_unlock(&trampoline_mutex);
- return image->data;
+ ksym->start = (unsigned long) data;
+ ksym->end = ksym->start + PAGE_SIZE;
+ bpf_ksym_add(ksym);
+ perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start,
+ PAGE_SIZE, false, ksym->name);
}
-void *bpf_image_alloc(void)
+void bpf_image_ksym_del(struct bpf_ksym *ksym)
{
- return __bpf_image_alloc(true);
+ bpf_ksym_del(ksym);
+ perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, ksym->start,
+ PAGE_SIZE, true, ksym->name);
}
-bool is_bpf_image_address(unsigned long addr)
+static void bpf_trampoline_ksym_add(struct bpf_trampoline *tr)
{
- bool ret;
-
- rcu_read_lock();
- ret = latch_tree_find((void *) addr, &image_tree, &image_tree_ops) != NULL;
- rcu_read_unlock();
+ struct bpf_ksym *ksym = &tr->ksym;
- return ret;
+ snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu", tr->key);
+ bpf_image_ksym_add(tr->image, ksym);
}
struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
goto out;
/* is_root was checked earlier. No need for bpf_jit_charge_modmem() */
- image = __bpf_image_alloc(false);
+ image = bpf_jit_alloc_exec_page();
if (!image) {
kfree(tr);
tr = NULL;
for (i = 0; i < BPF_TRAMP_MAX; i++)
INIT_HLIST_HEAD(&tr->progs_hlist[i]);
tr->image = image;
+ INIT_LIST_HEAD_RCU(&tr->ksym.lnode);
+ bpf_trampoline_ksym_add(tr);
out:
mutex_unlock(&trampoline_mutex);
return tr;
return ret;
}
-/* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50
- * bytes on x86. Pick a number to fit into BPF_IMAGE_SIZE / 2
- */
-#define BPF_MAX_TRAMP_PROGS 40
+static struct bpf_tramp_progs *
+bpf_trampoline_get_progs(const struct bpf_trampoline *tr, int *total)
+{
+ const struct bpf_prog_aux *aux;
+ struct bpf_tramp_progs *tprogs;
+ struct bpf_prog **progs;
+ int kind;
+
+ *total = 0;
+ tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL);
+ if (!tprogs)
+ return ERR_PTR(-ENOMEM);
+
+ for (kind = 0; kind < BPF_TRAMP_MAX; kind++) {
+ tprogs[kind].nr_progs = tr->progs_cnt[kind];
+ *total += tr->progs_cnt[kind];
+ progs = tprogs[kind].progs;
+
+ hlist_for_each_entry(aux, &tr->progs_hlist[kind], tramp_hlist)
+ *progs++ = aux->prog;
+ }
+ return tprogs;
+}
static int bpf_trampoline_update(struct bpf_trampoline *tr)
{
- void *old_image = tr->image + ((tr->selector + 1) & 1) * BPF_IMAGE_SIZE/2;
- void *new_image = tr->image + (tr->selector & 1) * BPF_IMAGE_SIZE/2;
- struct bpf_prog *progs_to_run[BPF_MAX_TRAMP_PROGS];
- int fentry_cnt = tr->progs_cnt[BPF_TRAMP_FENTRY];
- int fexit_cnt = tr->progs_cnt[BPF_TRAMP_FEXIT];
- struct bpf_prog **progs, **fentry, **fexit;
+ void *old_image = tr->image + ((tr->selector + 1) & 1) * PAGE_SIZE/2;
+ void *new_image = tr->image + (tr->selector & 1) * PAGE_SIZE/2;
+ struct bpf_tramp_progs *tprogs;
u32 flags = BPF_TRAMP_F_RESTORE_REGS;
- struct bpf_prog_aux *aux;
- int err;
+ int err, total;
+
+ tprogs = bpf_trampoline_get_progs(tr, &total);
+ if (IS_ERR(tprogs))
+ return PTR_ERR(tprogs);
- if (fentry_cnt + fexit_cnt == 0) {
+ if (total == 0) {
err = unregister_fentry(tr, old_image);
tr->selector = 0;
goto out;
}
- /* populate fentry progs */
- fentry = progs = progs_to_run;
- hlist_for_each_entry(aux, &tr->progs_hlist[BPF_TRAMP_FENTRY], tramp_hlist)
- *progs++ = aux->prog;
-
- /* populate fexit progs */
- fexit = progs;
- hlist_for_each_entry(aux, &tr->progs_hlist[BPF_TRAMP_FEXIT], tramp_hlist)
- *progs++ = aux->prog;
-
- if (fexit_cnt)
+ if (tprogs[BPF_TRAMP_FEXIT].nr_progs ||
+ tprogs[BPF_TRAMP_MODIFY_RETURN].nr_progs)
flags = BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME;
/* Though the second half of trampoline page is unused a task could be
* preempted task. Hence wait for tasks to voluntarily schedule or go
* to userspace.
*/
+
synchronize_rcu_tasks();
- err = arch_prepare_bpf_trampoline(new_image, new_image + BPF_IMAGE_SIZE / 2,
- &tr->func.model, flags,
- fentry, fentry_cnt,
- fexit, fexit_cnt,
+ err = arch_prepare_bpf_trampoline(new_image, new_image + PAGE_SIZE / 2,
+ &tr->func.model, flags, tprogs,
tr->func.addr);
if (err < 0)
goto out;
goto out;
tr->selector++;
out:
+ kfree(tprogs);
return err;
}
switch (t) {
case BPF_TRACE_FENTRY:
return BPF_TRAMP_FENTRY;
+ case BPF_MODIFY_RETURN:
+ return BPF_TRAMP_MODIFY_RETURN;
case BPF_TRACE_FEXIT:
return BPF_TRAMP_FEXIT;
default:
void bpf_trampoline_put(struct bpf_trampoline *tr)
{
- struct bpf_image *image;
-
if (!tr)
return;
mutex_lock(&trampoline_mutex);
goto out;
if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[BPF_TRAMP_FEXIT])))
goto out;
- image = container_of(tr->image, struct bpf_image, data);
- latch_tree_erase(&image->tnode, &image_tree, &image_tree_ops);
+ bpf_image_ksym_del(&tr->ksym);
/* wait for tasks to get out of trampoline before freeing it */
synchronize_rcu_tasks();
- bpf_jit_free_exec(image);
+ bpf_jit_free_exec(tr->image);
hlist_del(&tr->hlist);
kfree(tr);
out:
mutex_unlock(&trampoline_mutex);
}
-/* The logic is similar to BPF_PROG_RUN, but with explicit rcu and preempt that
- * are needed for trampoline. The macro is split into
+/* The logic is similar to BPF_PROG_RUN, but with an explicit
+ * rcu_read_lock() and migrate_disable() which are required
+ * for the trampoline. The macro is split into
* call _bpf_prog_enter
* call prog->bpf_func
* call __bpf_prog_exit
u64 start = 0;
rcu_read_lock();
- preempt_disable();
+ migrate_disable();
if (static_branch_unlikely(&bpf_stats_enabled_key))
start = sched_clock();
return start;
stats->nsecs += sched_clock() - start;
u64_stats_update_end(&stats->syncp);
}
- preempt_enable();
+ migrate_enable();
rcu_read_unlock();
}
int __weak
arch_prepare_bpf_trampoline(void *image, void *image_end,
const struct btf_func_model *m, u32 flags,
- struct bpf_prog **fentry_progs, int fentry_cnt,
- struct bpf_prog **fexit_progs, int fexit_cnt,
+ struct bpf_tramp_progs *tprogs,
void *orig_call)
{
return -ENOTSUPP;
projects / linux-2.6-microblaze.git / blobdiff