From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/kernel/bpf/arraymap.c | 678 +++++++++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 620 insertions(+), 58 deletions(-)
diff --git a/kernel/kernel/bpf/arraymap.c b/kernel/kernel/bpf/arraymap.c
index 0c17aab..f241bda 100644
--- a/kernel/kernel/bpf/arraymap.c
+++ b/kernel/kernel/bpf/arraymap.c
@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
* Copyright (c) 2016,2017 Facebook
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
*/
#include <linux/bpf.h>
#include <linux/btf.h>
@@ -18,11 +10,13 @@
#include <linux/filter.h>
#include <linux/perf_event.h>
#include <uapi/linux/btf.h>
+#include <linux/rcupdate_trace.h>
#include "map_in_map.h"
#define ARRAY_CREATE_FLAG_MASK \
- (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
+ (BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
+ BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
static void bpf_array_free_percpu(struct bpf_array *array)
{
@@ -63,7 +57,16 @@
if (attr->max_entries == 0 || attr->key_size != 4 ||
attr->value_size == 0 ||
attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
+ !bpf_map_flags_access_ok(attr->map_flags) ||
(percpu && numa_node != NUMA_NO_NODE))
+ return -EINVAL;
+
+ if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
+ attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
+ return -EINVAL;
+
+ if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
+ attr->map_flags & BPF_F_PRESERVE_ELEMS)
return -EINVAL;
if (attr->value_size > KMALLOC_MAX_SIZE)
@@ -80,8 +83,9 @@
bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
int ret, numa_node = bpf_map_attr_numa_node(attr);
u32 elem_size, index_mask, max_entries;
- bool unpriv = !capable(CAP_SYS_ADMIN);
+ bool bypass_spec_v1 = bpf_bypass_spec_v1();
u64 cost, array_size, mask64;
+ struct bpf_map_memory mem;
struct bpf_array *array;
elem_size = round_up(attr->value_size, 8);
@@ -97,7 +101,7 @@
mask64 -= 1;
index_mask = mask64;
- if (unpriv) {
+ if (!bypass_spec_v1) {
/* round up array size to nearest power of 2,
* since cpu will speculate within index_mask limits
*/
@@ -108,39 +112,58 @@
}
array_size = sizeof(*array);
- if (percpu)
+ if (percpu) {
array_size += (u64) max_entries * sizeof(void *);
- else
- array_size += (u64) max_entries * elem_size;
+ } else {
+ /* rely on vmalloc() to return page-aligned memory and
+ * ensure array->value is exactly page-aligned
+ */
+ if (attr->map_flags & BPF_F_MMAPABLE) {
+ array_size = PAGE_ALIGN(array_size);
+ array_size += PAGE_ALIGN((u64) max_entries * elem_size);
+ } else {
+ array_size += (u64) max_entries * elem_size;
+ }
+ }
/* make sure there is no u32 overflow later in round_up() */
cost = array_size;
- if (cost >= U32_MAX - PAGE_SIZE)
- return ERR_PTR(-ENOMEM);
- if (percpu) {
+ if (percpu)
cost += (u64)attr->max_entries * elem_size * num_possible_cpus();
- if (cost >= U32_MAX - PAGE_SIZE)
- return ERR_PTR(-ENOMEM);
- }
- cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
- ret = bpf_map_precharge_memlock(cost);
+ ret = bpf_map_charge_init(&mem, cost);
if (ret < 0)
return ERR_PTR(ret);
/* allocate all map elements and zero-initialize them */
- array = bpf_map_area_alloc(array_size, numa_node);
- if (!array)
+ if (attr->map_flags & BPF_F_MMAPABLE) {
+ void *data;
+
+ /* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
+ data = bpf_map_area_mmapable_alloc(array_size, numa_node);
+ if (!data) {
+ bpf_map_charge_finish(&mem);
+ return ERR_PTR(-ENOMEM);
+ }
+ array = data + PAGE_ALIGN(sizeof(struct bpf_array))
+ - offsetof(struct bpf_array, value);
+ } else {
+ array = bpf_map_area_alloc(array_size, numa_node);
+ }
+ if (!array) {
+ bpf_map_charge_finish(&mem);
return ERR_PTR(-ENOMEM);
+ }
array->index_mask = index_mask;
- array->map.unpriv_array = unpriv;
+ array->map.bypass_spec_v1 = bypass_spec_v1;
/* copy mandatory map attributes */
bpf_map_init_from_attr(&array->map, attr);
- array->map.pages = cost;
+ bpf_map_charge_move(&array->map.memory, &mem);
array->elem_size = elem_size;
if (percpu && bpf_array_alloc_percpu(array)) {
+ bpf_map_charge_finish(&array->map.memory);
bpf_map_area_free(array);
return ERR_PTR(-ENOMEM);
}
@@ -160,8 +183,38 @@
return array->value + array->elem_size * (index & array->index_mask);
}
+static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
+ u32 off)
+{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+
+ if (map->max_entries != 1)
+ return -ENOTSUPP;
+ if (off >= map->value_size)
+ return -EINVAL;
+
+ *imm = (unsigned long)array->value;
+ return 0;
+}
+
+static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
+ u32 *off)
+{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+ u64 base = (unsigned long)array->value;
+ u64 range = array->elem_size;
+
+ if (map->max_entries != 1)
+ return -ENOTSUPP;
+ if (imm < base || imm >= base + range)
+ return -ENOENT;
+
+ *off = imm - base;
+ return 0;
+}
+
/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
-static u32 array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
+static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
struct bpf_insn *insn = insn_buf;
@@ -170,9 +223,12 @@
const int map_ptr = BPF_REG_1;
const int index = BPF_REG_2;
+ if (map->map_flags & BPF_F_INNER_MAP)
+ return -EOPNOTSUPP;
+
*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
- if (map->unpriv_array) {
+ if (!map->bypass_spec_v1) {
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
} else {
@@ -253,8 +309,9 @@
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
+ char *val;
- if (unlikely(map_flags > BPF_EXIST))
+ if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
/* unknown flags */
return -EINVAL;
@@ -262,17 +319,25 @@
/* all elements were pre-allocated, cannot insert a new one */
return -E2BIG;
- if (unlikely(map_flags == BPF_NOEXIST))
+ if (unlikely(map_flags & BPF_NOEXIST))
/* all elements already exist */
return -EEXIST;
- if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
+ if (unlikely((map_flags & BPF_F_LOCK) &&
+ !map_value_has_spin_lock(map)))
+ return -EINVAL;
+
+ if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
memcpy(this_cpu_ptr(array->pptrs[index & array->index_mask]),
value, map->value_size);
- else
- memcpy(array->value +
- array->elem_size * (index & array->index_mask),
- value, map->value_size);
+ } else {
+ val = array->value +
+ array->elem_size * (index & array->index_mask);
+ if (map_flags & BPF_F_LOCK)
+ copy_map_value_locked(map, val, value, false);
+ else
+ copy_map_value(map, val, value);
+ }
return 0;
}
@@ -320,22 +385,23 @@
return -EINVAL;
}
+static void *array_map_vmalloc_addr(struct bpf_array *array)
+{
+ return (void *)round_down((unsigned long)array, PAGE_SIZE);
+}
+
/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
static void array_map_free(struct bpf_map *map)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
- /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
- * so the programs (can be more than one that used this map) were
- * disconnected from events. Wait for outstanding programs to complete
- * and free the array
- */
- synchronize_rcu();
-
if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
bpf_array_free_percpu(array);
- bpf_map_area_free(array);
+ if (array->map.map_flags & BPF_F_MMAPABLE)
+ bpf_map_area_free(array_map_vmalloc_addr(array));
+ else
+ bpf_map_area_free(array);
}
static void array_map_seq_show_elem(struct bpf_map *map, void *key,
@@ -351,18 +417,55 @@
return;
}
- seq_printf(m, "%u: ", *(u32 *)key);
+ if (map->btf_key_type_id)
+ seq_printf(m, "%u: ", *(u32 *)key);
btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
seq_puts(m, "\n");
rcu_read_unlock();
}
+static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
+ struct seq_file *m)
+{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+ u32 index = *(u32 *)key;
+ void __percpu *pptr;
+ int cpu;
+
+ rcu_read_lock();
+
+ seq_printf(m, "%u: {\n", *(u32 *)key);
+ pptr = array->pptrs[index & array->index_mask];
+ for_each_possible_cpu(cpu) {
+ seq_printf(m, "\tcpu%d: ", cpu);
+ btf_type_seq_show(map->btf, map->btf_value_type_id,
+ per_cpu_ptr(pptr, cpu), m);
+ seq_puts(m, "\n");
+ }
+ seq_puts(m, "}\n");
+
+ rcu_read_unlock();
+}
+
static int array_map_check_btf(const struct bpf_map *map,
+ const struct btf *btf,
const struct btf_type *key_type,
const struct btf_type *value_type)
{
u32 int_data;
+
+ /* One exception for keyless BTF: .bss/.data/.rodata map */
+ if (btf_type_is_void(key_type)) {
+ if (map->map_type != BPF_MAP_TYPE_ARRAY ||
+ map->max_entries != 1)
+ return -EINVAL;
+
+ if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
+ return -EINVAL;
+
+ return 0;
+ }
if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
return -EINVAL;
@@ -377,7 +480,176 @@
return 0;
}
+static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
+{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+ pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
+
+ if (!(map->map_flags & BPF_F_MMAPABLE))
+ return -EINVAL;
+
+ if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
+ PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
+ return -EINVAL;
+
+ return remap_vmalloc_range(vma, array_map_vmalloc_addr(array),
+ vma->vm_pgoff + pgoff);
+}
+
+static bool array_map_meta_equal(const struct bpf_map *meta0,
+ const struct bpf_map *meta1)
+{
+ if (!bpf_map_meta_equal(meta0, meta1))
+ return false;
+ return meta0->map_flags & BPF_F_INNER_MAP ? true :
+ meta0->max_entries == meta1->max_entries;
+}
+
+struct bpf_iter_seq_array_map_info {
+ struct bpf_map *map;
+ void *percpu_value_buf;
+ u32 index;
+};
+
+static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ struct bpf_iter_seq_array_map_info *info = seq->private;
+ struct bpf_map *map = info->map;
+ struct bpf_array *array;
+ u32 index;
+
+ if (info->index >= map->max_entries)
+ return NULL;
+
+ if (*pos == 0)
+ ++*pos;
+ array = container_of(map, struct bpf_array, map);
+ index = info->index & array->index_mask;
+ if (info->percpu_value_buf)
+ return array->pptrs[index];
+ return array->value + array->elem_size * index;
+}
+
+static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct bpf_iter_seq_array_map_info *info = seq->private;
+ struct bpf_map *map = info->map;
+ struct bpf_array *array;
+ u32 index;
+
+ ++*pos;
+ ++info->index;
+ if (info->index >= map->max_entries)
+ return NULL;
+
+ array = container_of(map, struct bpf_array, map);
+ index = info->index & array->index_mask;
+ if (info->percpu_value_buf)
+ return array->pptrs[index];
+ return array->value + array->elem_size * index;
+}
+
+static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
+{
+ struct bpf_iter_seq_array_map_info *info = seq->private;
+ struct bpf_iter__bpf_map_elem ctx = {};
+ struct bpf_map *map = info->map;
+ struct bpf_iter_meta meta;
+ struct bpf_prog *prog;
+ int off = 0, cpu = 0;
+ void __percpu **pptr;
+ u32 size;
+
+ meta.seq = seq;
+ prog = bpf_iter_get_info(&meta, v == NULL);
+ if (!prog)
+ return 0;
+
+ ctx.meta = &meta;
+ ctx.map = info->map;
+ if (v) {
+ ctx.key = &info->index;
+
+ if (!info->percpu_value_buf) {
+ ctx.value = v;
+ } else {
+ pptr = v;
+ size = round_up(map->value_size, 8);
+ for_each_possible_cpu(cpu) {
+ bpf_long_memcpy(info->percpu_value_buf + off,
+ per_cpu_ptr(pptr, cpu),
+ size);
+ off += size;
+ }
+ ctx.value = info->percpu_value_buf;
+ }
+ }
+
+ return bpf_iter_run_prog(prog, &ctx);
+}
+
+static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
+{
+ return __bpf_array_map_seq_show(seq, v);
+}
+
+static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
+{
+ if (!v)
+ (void)__bpf_array_map_seq_show(seq, NULL);
+}
+
+static int bpf_iter_init_array_map(void *priv_data,
+ struct bpf_iter_aux_info *aux)
+{
+ struct bpf_iter_seq_array_map_info *seq_info = priv_data;
+ struct bpf_map *map = aux->map;
+ void *value_buf;
+ u32 buf_size;
+
+ if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
+ buf_size = round_up(map->value_size, 8) * num_possible_cpus();
+ value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
+ if (!value_buf)
+ return -ENOMEM;
+
+ seq_info->percpu_value_buf = value_buf;
+ }
+
+ /* bpf_iter_attach_map() acquires a map uref, and the uref may be
+ * released before or in the middle of iterating map elements, so
+ * acquire an extra map uref for iterator.
+ */
+ bpf_map_inc_with_uref(map);
+ seq_info->map = map;
+ return 0;
+}
+
+static void bpf_iter_fini_array_map(void *priv_data)
+{
+ struct bpf_iter_seq_array_map_info *seq_info = priv_data;
+
+ bpf_map_put_with_uref(seq_info->map);
+ kfree(seq_info->percpu_value_buf);
+}
+
+static const struct seq_operations bpf_array_map_seq_ops = {
+ .start = bpf_array_map_seq_start,
+ .next = bpf_array_map_seq_next,
+ .stop = bpf_array_map_seq_stop,
+ .show = bpf_array_map_seq_show,
+};
+
+static const struct bpf_iter_seq_info iter_seq_info = {
+ .seq_ops = &bpf_array_map_seq_ops,
+ .init_seq_private = bpf_iter_init_array_map,
+ .fini_seq_private = bpf_iter_fini_array_map,
+ .seq_priv_size = sizeof(struct bpf_iter_seq_array_map_info),
+};
+
+static int array_map_btf_id;
const struct bpf_map_ops array_map_ops = {
+ .map_meta_equal = array_map_meta_equal,
.map_alloc_check = array_map_alloc_check,
.map_alloc = array_map_alloc,
.map_free = array_map_free,
@@ -386,11 +658,21 @@
.map_update_elem = array_map_update_elem,
.map_delete_elem = array_map_delete_elem,
.map_gen_lookup = array_map_gen_lookup,
+ .map_direct_value_addr = array_map_direct_value_addr,
+ .map_direct_value_meta = array_map_direct_value_meta,
+ .map_mmap = array_map_mmap,
.map_seq_show_elem = array_map_seq_show_elem,
.map_check_btf = array_map_check_btf,
+ .map_lookup_batch = generic_map_lookup_batch,
+ .map_update_batch = generic_map_update_batch,
+ .map_btf_name = "bpf_array",
+ .map_btf_id = &array_map_btf_id,
+ .iter_seq_info = &iter_seq_info,
};
+static int percpu_array_map_btf_id;
const struct bpf_map_ops percpu_array_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = array_map_alloc_check,
.map_alloc = array_map_alloc,
.map_free = array_map_free,
@@ -398,13 +680,20 @@
.map_lookup_elem = percpu_array_map_lookup_elem,
.map_update_elem = array_map_update_elem,
.map_delete_elem = array_map_delete_elem,
+ .map_seq_show_elem = percpu_array_map_seq_show_elem,
.map_check_btf = array_map_check_btf,
+ .map_btf_name = "bpf_array",
+ .map_btf_id = &percpu_array_map_btf_id,
+ .iter_seq_info = &iter_seq_info,
};
static int fd_array_map_alloc_check(union bpf_attr *attr)
{
/* only file descriptors can be stored in this type of map */
if (attr->value_size != sizeof(u32))
+ return -EINVAL;
+ /* Program read-only/write-only not supported for special maps yet. */
+ if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
return -EINVAL;
return array_map_alloc_check(attr);
}
@@ -413,8 +702,6 @@
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
int i;
-
- synchronize_rcu();
/* make sure it's empty */
for (i = 0; i < array->map.max_entries; i++)
@@ -425,7 +712,7 @@
static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
{
- return NULL;
+ return ERR_PTR(-EOPNOTSUPP);
}
/* only called from syscall */
@@ -467,10 +754,17 @@
if (IS_ERR(new_ptr))
return PTR_ERR(new_ptr);
- old_ptr = xchg(array->ptrs + index, new_ptr);
+ if (map->ops->map_poke_run) {
+ mutex_lock(&array->aux->poke_mutex);
+ old_ptr = xchg(array->ptrs + index, new_ptr);
+ map->ops->map_poke_run(map, index, old_ptr, new_ptr);
+ mutex_unlock(&array->aux->poke_mutex);
+ } else {
+ old_ptr = xchg(array->ptrs + index, new_ptr);
+ }
+
if (old_ptr)
map->ops->map_fd_put_ptr(old_ptr);
-
return 0;
}
@@ -483,7 +777,15 @@
if (index >= array->map.max_entries)
return -E2BIG;
- old_ptr = xchg(array->ptrs + index, NULL);
+ if (map->ops->map_poke_run) {
+ mutex_lock(&array->aux->poke_mutex);
+ old_ptr = xchg(array->ptrs + index, NULL);
+ map->ops->map_poke_run(map, index, old_ptr, NULL);
+ mutex_unlock(&array->aux->poke_mutex);
+ } else {
+ old_ptr = xchg(array->ptrs + index, NULL);
+ }
+
if (old_ptr) {
map->ops->map_fd_put_ptr(old_ptr);
return 0;
@@ -529,18 +831,257 @@
fd_array_map_delete_elem(map, &i);
}
+static void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
+ struct seq_file *m)
+{
+ void **elem, *ptr;
+ u32 prog_id;
+
+ rcu_read_lock();
+
+ elem = array_map_lookup_elem(map, key);
+ if (elem) {
+ ptr = READ_ONCE(*elem);
+ if (ptr) {
+ seq_printf(m, "%u: ", *(u32 *)key);
+ prog_id = prog_fd_array_sys_lookup_elem(ptr);
+ btf_type_seq_show(map->btf, map->btf_value_type_id,
+ &prog_id, m);
+ seq_puts(m, "\n");
+ }
+ }
+
+ rcu_read_unlock();
+}
+
+struct prog_poke_elem {
+ struct list_head list;
+ struct bpf_prog_aux *aux;
+};
+
+static int prog_array_map_poke_track(struct bpf_map *map,
+ struct bpf_prog_aux *prog_aux)
+{
+ struct prog_poke_elem *elem;
+ struct bpf_array_aux *aux;
+ int ret = 0;
+
+ aux = container_of(map, struct bpf_array, map)->aux;
+ mutex_lock(&aux->poke_mutex);
+ list_for_each_entry(elem, &aux->poke_progs, list) {
+ if (elem->aux == prog_aux)
+ goto out;
+ }
+
+ elem = kmalloc(sizeof(*elem), GFP_KERNEL);
+ if (!elem) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ INIT_LIST_HEAD(&elem->list);
+ /* We must track the program's aux info at this point in time
+ * since the program pointer itself may not be stable yet, see
+ * also comment in prog_array_map_poke_run().
+ */
+ elem->aux = prog_aux;
+
+ list_add_tail(&elem->list, &aux->poke_progs);
+out:
+ mutex_unlock(&aux->poke_mutex);
+ return ret;
+}
+
+static void prog_array_map_poke_untrack(struct bpf_map *map,
+ struct bpf_prog_aux *prog_aux)
+{
+ struct prog_poke_elem *elem, *tmp;
+ struct bpf_array_aux *aux;
+
+ aux = container_of(map, struct bpf_array, map)->aux;
+ mutex_lock(&aux->poke_mutex);
+ list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
+ if (elem->aux == prog_aux) {
+ list_del_init(&elem->list);
+ kfree(elem);
+ break;
+ }
+ }
+ mutex_unlock(&aux->poke_mutex);
+}
+
+static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
+ struct bpf_prog *old,
+ struct bpf_prog *new)
+{
+ u8 *old_addr, *new_addr, *old_bypass_addr;
+ struct prog_poke_elem *elem;
+ struct bpf_array_aux *aux;
+
+ aux = container_of(map, struct bpf_array, map)->aux;
+ WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
+
+ list_for_each_entry(elem, &aux->poke_progs, list) {
+ struct bpf_jit_poke_descriptor *poke;
+ int i, ret;
+
+ for (i = 0; i < elem->aux->size_poke_tab; i++) {
+ poke = &elem->aux->poke_tab[i];
+
+ /* Few things to be aware of:
+ *
+ * 1) We can only ever access aux in this context, but
+ * not aux->prog since it might not be stable yet and
+ * there could be danger of use after free otherwise.
+ * 2) Initially when we start tracking aux, the program
+ * is not JITed yet and also does not have a kallsyms
+ * entry. We skip these as poke->tailcall_target_stable
+ * is not active yet. The JIT will do the final fixup
+ * before setting it stable. The various
+ * poke->tailcall_target_stable are successively
+ * activated, so tail call updates can arrive from here
+ * while JIT is still finishing its final fixup for
+ * non-activated poke entries.
+ * 3) On program teardown, the program's kallsym entry gets
+ * removed out of RCU callback, but we can only untrack
+ * from sleepable context, therefore bpf_arch_text_poke()
+ * might not see that this is in BPF text section and
+ * bails out with -EINVAL. As these are unreachable since
+ * RCU grace period already passed, we simply skip them.
+ * 4) Also programs reaching refcount of zero while patching
+ * is in progress is okay since we're protected under
+ * poke_mutex and untrack the programs before the JIT
+ * buffer is freed. When we're still in the middle of
+ * patching and suddenly kallsyms entry of the program
+ * gets evicted, we just skip the rest which is fine due
+ * to point 3).
+ * 5) Any other error happening below from bpf_arch_text_poke()
+ * is a unexpected bug.
+ */
+ if (!READ_ONCE(poke->tailcall_target_stable))
+ continue;
+ if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
+ continue;
+ if (poke->tail_call.map != map ||
+ poke->tail_call.key != key)
+ continue;
+
+ old_bypass_addr = old ? NULL : poke->bypass_addr;
+ old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
+ new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
+
+ if (new) {
+ ret = bpf_arch_text_poke(poke->tailcall_target,
+ BPF_MOD_JUMP,
+ old_addr, new_addr);
+ BUG_ON(ret < 0 && ret != -EINVAL);
+ if (!old) {
+ ret = bpf_arch_text_poke(poke->tailcall_bypass,
+ BPF_MOD_JUMP,
+ poke->bypass_addr,
+ NULL);
+ BUG_ON(ret < 0 && ret != -EINVAL);
+ }
+ } else {
+ ret = bpf_arch_text_poke(poke->tailcall_bypass,
+ BPF_MOD_JUMP,
+ old_bypass_addr,
+ poke->bypass_addr);
+ BUG_ON(ret < 0 && ret != -EINVAL);
+ /* let other CPUs finish the execution of program
+ * so that it will not possible to expose them
+ * to invalid nop, stack unwind, nop state
+ */
+ if (!ret)
+ synchronize_rcu();
+ ret = bpf_arch_text_poke(poke->tailcall_target,
+ BPF_MOD_JUMP,
+ old_addr, NULL);
+ BUG_ON(ret < 0 && ret != -EINVAL);
+ }
+ }
+ }
+}
+
+static void prog_array_map_clear_deferred(struct work_struct *work)
+{
+ struct bpf_map *map = container_of(work, struct bpf_array_aux,
+ work)->map;
+ bpf_fd_array_map_clear(map);
+ bpf_map_put(map);
+}
+
+static void prog_array_map_clear(struct bpf_map *map)
+{
+ struct bpf_array_aux *aux = container_of(map, struct bpf_array,
+ map)->aux;
+ bpf_map_inc(map);
+ schedule_work(&aux->work);
+}
+
+static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
+{
+ struct bpf_array_aux *aux;
+ struct bpf_map *map;
+
+ aux = kzalloc(sizeof(*aux), GFP_KERNEL);
+ if (!aux)
+ return ERR_PTR(-ENOMEM);
+
+ INIT_WORK(&aux->work, prog_array_map_clear_deferred);
+ INIT_LIST_HEAD(&aux->poke_progs);
+ mutex_init(&aux->poke_mutex);
+ spin_lock_init(&aux->owner.lock);
+
+ map = array_map_alloc(attr);
+ if (IS_ERR(map)) {
+ kfree(aux);
+ return map;
+ }
+
+ container_of(map, struct bpf_array, map)->aux = aux;
+ aux->map = map;
+
+ return map;
+}
+
+static void prog_array_map_free(struct bpf_map *map)
+{
+ struct prog_poke_elem *elem, *tmp;
+ struct bpf_array_aux *aux;
+
+ aux = container_of(map, struct bpf_array, map)->aux;
+ list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
+ list_del_init(&elem->list);
+ kfree(elem);
+ }
+ kfree(aux);
+ fd_array_map_free(map);
+}
+
+/* prog_array->aux->{type,jited} is a runtime binding.
+ * Doing static check alone in the verifier is not enough.
+ * Thus, prog_array_map cannot be used as an inner_map
+ * and map_meta_equal is not implemented.
+ */
+static int prog_array_map_btf_id;
const struct bpf_map_ops prog_array_map_ops = {
.map_alloc_check = fd_array_map_alloc_check,
- .map_alloc = array_map_alloc,
- .map_free = fd_array_map_free,
+ .map_alloc = prog_array_map_alloc,
+ .map_free = prog_array_map_free,
+ .map_poke_track = prog_array_map_poke_track,
+ .map_poke_untrack = prog_array_map_poke_untrack,
+ .map_poke_run = prog_array_map_poke_run,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = fd_array_map_lookup_elem,
.map_delete_elem = fd_array_map_delete_elem,
.map_fd_get_ptr = prog_fd_array_get_ptr,
.map_fd_put_ptr = prog_fd_array_put_ptr,
.map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
- .map_release_uref = bpf_fd_array_map_clear,
- .map_check_btf = map_check_no_btf,
+ .map_release_uref = prog_array_map_clear,
+ .map_seq_show_elem = prog_array_map_seq_show_elem,
+ .map_btf_name = "bpf_array",
+ .map_btf_id = &prog_array_map_btf_id,
};
static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
@@ -610,6 +1151,9 @@
struct bpf_event_entry *ee;
int i;
+ if (map->map_flags & BPF_F_PRESERVE_ELEMS)
+ return;
+
rcu_read_lock();
for (i = 0; i < array->map.max_entries; i++) {
ee = READ_ONCE(array->ptrs[i]);
@@ -619,10 +1163,19 @@
rcu_read_unlock();
}
+static void perf_event_fd_array_map_free(struct bpf_map *map)
+{
+ if (map->map_flags & BPF_F_PRESERVE_ELEMS)
+ bpf_fd_array_map_clear(map);
+ fd_array_map_free(map);
+}
+
+static int perf_event_array_map_btf_id;
const struct bpf_map_ops perf_event_array_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = fd_array_map_alloc_check,
.map_alloc = array_map_alloc,
- .map_free = fd_array_map_free,
+ .map_free = perf_event_fd_array_map_free,
.map_get_next_key = array_map_get_next_key,
.map_lookup_elem = fd_array_map_lookup_elem,
.map_delete_elem = fd_array_map_delete_elem,
@@ -630,6 +1183,8 @@
.map_fd_put_ptr = perf_event_fd_array_put_ptr,
.map_release = perf_event_fd_array_release,
.map_check_btf = map_check_no_btf,
+ .map_btf_name = "bpf_array",
+ .map_btf_id = &perf_event_array_map_btf_id,
};
#ifdef CONFIG_CGROUPS
@@ -652,7 +1207,9 @@
fd_array_map_free(map);
}
+static int cgroup_array_map_btf_id;
const struct bpf_map_ops cgroup_array_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
.map_alloc_check = fd_array_map_alloc_check,
.map_alloc = array_map_alloc,
.map_free = cgroup_fd_array_free,
@@ -662,6 +1219,8 @@
.map_fd_get_ptr = cgroup_fd_array_get_ptr,
.map_fd_put_ptr = cgroup_fd_array_put_ptr,
.map_check_btf = map_check_no_btf,
+ .map_btf_name = "bpf_array",
+ .map_btf_id = &cgroup_array_map_btf_id,
};
#endif
@@ -704,7 +1263,7 @@
return READ_ONCE(*inner_map);
}
-static u32 array_of_map_gen_lookup(struct bpf_map *map,
+static int array_of_map_gen_lookup(struct bpf_map *map,
struct bpf_insn *insn_buf)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
@@ -716,7 +1275,7 @@
*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
- if (map->unpriv_array) {
+ if (!map->bypass_spec_v1) {
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
} else {
@@ -735,6 +1294,7 @@
return insn - insn_buf;
}
+static int array_of_maps_map_btf_id;
const struct bpf_map_ops array_of_maps_map_ops = {
.map_alloc_check = fd_array_map_alloc_check,
.map_alloc = array_of_map_alloc,
@@ -747,4 +1307,6 @@
.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
.map_gen_lookup = array_of_map_gen_lookup,
.map_check_btf = map_check_no_btf,
+ .map_btf_name = "bpf_array",
+ .map_btf_id = &array_of_maps_map_btf_id,
};
--
Gitblit v1.6.2