1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3  * Copyright (c) 2016,2017 Facebook
4  */
5 #include <linux/bpf.h>
6 #include <linux/btf.h>
7 #include <linux/err.h>
8 #include <linux/slab.h>
9 #include <linux/mm.h>
10 #include <linux/filter.h>
11 #include <linux/perf_event.h>
12 #include <uapi/linux/btf.h>
13 #include <linux/rcupdate_trace.h>
14 #include <linux/btf_ids.h>
15 
16 #include "map_in_map.h"
17 
18 #define ARRAY_CREATE_FLAG_MASK \
19 	(BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
20 	 BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
21 
bpf_array_free_percpu(struct bpf_array * array)22 static void bpf_array_free_percpu(struct bpf_array *array)
23 {
24 	int i;
25 
26 	for (i = 0; i < array->map.max_entries; i++) {
27 		free_percpu(array->pptrs[i]);
28 		cond_resched();
29 	}
30 }
31 
bpf_array_alloc_percpu(struct bpf_array * array)32 static int bpf_array_alloc_percpu(struct bpf_array *array)
33 {
34 	void __percpu *ptr;
35 	int i;
36 
37 	for (i = 0; i < array->map.max_entries; i++) {
38 		ptr = bpf_map_alloc_percpu(&array->map, array->elem_size, 8,
39 					   GFP_USER | __GFP_NOWARN);
40 		if (!ptr) {
41 			bpf_array_free_percpu(array);
42 			return -ENOMEM;
43 		}
44 		array->pptrs[i] = ptr;
45 		cond_resched();
46 	}
47 
48 	return 0;
49 }
50 
51 /* Called from syscall */
array_map_alloc_check(union bpf_attr * attr)52 int array_map_alloc_check(union bpf_attr *attr)
53 {
54 	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
55 	int numa_node = bpf_map_attr_numa_node(attr);
56 
57 	/* check sanity of attributes */
58 	if (attr->max_entries == 0 || attr->key_size != 4 ||
59 	    attr->value_size == 0 ||
60 	    attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
61 	    !bpf_map_flags_access_ok(attr->map_flags) ||
62 	    (percpu && numa_node != NUMA_NO_NODE))
63 		return -EINVAL;
64 
65 	if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
66 	    attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
67 		return -EINVAL;
68 
69 	if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
70 	    attr->map_flags & BPF_F_PRESERVE_ELEMS)
71 		return -EINVAL;
72 
73 	/* avoid overflow on round_up(map->value_size) */
74 	if (attr->value_size > INT_MAX)
75 		return -E2BIG;
76 
77 	return 0;
78 }
79 
array_map_alloc(union bpf_attr * attr)80 static struct bpf_map *array_map_alloc(union bpf_attr *attr)
81 {
82 	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
83 	int numa_node = bpf_map_attr_numa_node(attr);
84 	u32 elem_size, index_mask, max_entries;
85 	bool bypass_spec_v1 = bpf_bypass_spec_v1();
86 	u64 array_size, mask64;
87 	struct bpf_array *array;
88 
89 	elem_size = round_up(attr->value_size, 8);
90 
91 	max_entries = attr->max_entries;
92 
93 	/* On 32 bit archs roundup_pow_of_two() with max_entries that has
94 	 * upper most bit set in u32 space is undefined behavior due to
95 	 * resulting 1U << 32, so do it manually here in u64 space.
96 	 */
97 	mask64 = fls_long(max_entries - 1);
98 	mask64 = 1ULL << mask64;
99 	mask64 -= 1;
100 
101 	index_mask = mask64;
102 	if (!bypass_spec_v1) {
103 		/* round up array size to nearest power of 2,
104 		 * since cpu will speculate within index_mask limits
105 		 */
106 		max_entries = index_mask + 1;
107 		/* Check for overflows. */
108 		if (max_entries < attr->max_entries)
109 			return ERR_PTR(-E2BIG);
110 	}
111 
112 	array_size = sizeof(*array);
113 	if (percpu) {
114 		array_size += (u64) max_entries * sizeof(void *);
115 	} else {
116 		/* rely on vmalloc() to return page-aligned memory and
117 		 * ensure array->value is exactly page-aligned
118 		 */
119 		if (attr->map_flags & BPF_F_MMAPABLE) {
120 			array_size = PAGE_ALIGN(array_size);
121 			array_size += PAGE_ALIGN((u64) max_entries * elem_size);
122 		} else {
123 			array_size += (u64) max_entries * elem_size;
124 		}
125 	}
126 
127 	/* allocate all map elements and zero-initialize them */
128 	if (attr->map_flags & BPF_F_MMAPABLE) {
129 		void *data;
130 
131 		/* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
132 		data = bpf_map_area_mmapable_alloc(array_size, numa_node);
133 		if (!data)
134 			return ERR_PTR(-ENOMEM);
135 		array = data + PAGE_ALIGN(sizeof(struct bpf_array))
136 			- offsetof(struct bpf_array, value);
137 	} else {
138 		array = bpf_map_area_alloc(array_size, numa_node);
139 	}
140 	if (!array)
141 		return ERR_PTR(-ENOMEM);
142 	array->index_mask = index_mask;
143 	array->map.bypass_spec_v1 = bypass_spec_v1;
144 
145 	/* copy mandatory map attributes */
146 	bpf_map_init_from_attr(&array->map, attr);
147 	array->elem_size = elem_size;
148 
149 	if (percpu && bpf_array_alloc_percpu(array)) {
150 		bpf_map_area_free(array);
151 		return ERR_PTR(-ENOMEM);
152 	}
153 
154 	return &array->map;
155 }
156 
array_map_elem_ptr(struct bpf_array * array,u32 index)157 static void *array_map_elem_ptr(struct bpf_array* array, u32 index)
158 {
159 	return array->value + (u64)array->elem_size * index;
160 }
161 
162 /* Called from syscall or from eBPF program */
array_map_lookup_elem(struct bpf_map * map,void * key)163 static void *array_map_lookup_elem(struct bpf_map *map, void *key)
164 {
165 	struct bpf_array *array = container_of(map, struct bpf_array, map);
166 	u32 index = *(u32 *)key;
167 
168 	if (unlikely(index >= array->map.max_entries))
169 		return NULL;
170 
171 	return array->value + (u64)array->elem_size * (index & array->index_mask);
172 }
173 
array_map_direct_value_addr(const struct bpf_map * map,u64 * imm,u32 off)174 static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
175 				       u32 off)
176 {
177 	struct bpf_array *array = container_of(map, struct bpf_array, map);
178 
179 	if (map->max_entries != 1)
180 		return -ENOTSUPP;
181 	if (off >= map->value_size)
182 		return -EINVAL;
183 
184 	*imm = (unsigned long)array->value;
185 	return 0;
186 }
187 
array_map_direct_value_meta(const struct bpf_map * map,u64 imm,u32 * off)188 static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
189 				       u32 *off)
190 {
191 	struct bpf_array *array = container_of(map, struct bpf_array, map);
192 	u64 base = (unsigned long)array->value;
193 	u64 range = array->elem_size;
194 
195 	if (map->max_entries != 1)
196 		return -ENOTSUPP;
197 	if (imm < base || imm >= base + range)
198 		return -ENOENT;
199 
200 	*off = imm - base;
201 	return 0;
202 }
203 
204 /* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
array_map_gen_lookup(struct bpf_map * map,struct bpf_insn * insn_buf)205 static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
206 {
207 	struct bpf_array *array = container_of(map, struct bpf_array, map);
208 	struct bpf_insn *insn = insn_buf;
209 	u32 elem_size = array->elem_size;
210 	const int ret = BPF_REG_0;
211 	const int map_ptr = BPF_REG_1;
212 	const int index = BPF_REG_2;
213 
214 	if (map->map_flags & BPF_F_INNER_MAP)
215 		return -EOPNOTSUPP;
216 
217 	*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
218 	*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
219 	if (!map->bypass_spec_v1) {
220 		*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
221 		*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
222 	} else {
223 		*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
224 	}
225 
226 	if (is_power_of_2(elem_size)) {
227 		*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
228 	} else {
229 		*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
230 	}
231 	*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
232 	*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
233 	*insn++ = BPF_MOV64_IMM(ret, 0);
234 	return insn - insn_buf;
235 }
236 
237 /* Called from eBPF program */
percpu_array_map_lookup_elem(struct bpf_map * map,void * key)238 static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
239 {
240 	struct bpf_array *array = container_of(map, struct bpf_array, map);
241 	u32 index = *(u32 *)key;
242 
243 	if (unlikely(index >= array->map.max_entries))
244 		return NULL;
245 
246 	return this_cpu_ptr(array->pptrs[index & array->index_mask]);
247 }
248 
percpu_array_map_lookup_percpu_elem(struct bpf_map * map,void * key,u32 cpu)249 static void *percpu_array_map_lookup_percpu_elem(struct bpf_map *map, void *key, u32 cpu)
250 {
251 	struct bpf_array *array = container_of(map, struct bpf_array, map);
252 	u32 index = *(u32 *)key;
253 
254 	if (cpu >= nr_cpu_ids)
255 		return NULL;
256 
257 	if (unlikely(index >= array->map.max_entries))
258 		return NULL;
259 
260 	return per_cpu_ptr(array->pptrs[index & array->index_mask], cpu);
261 }
262 
bpf_percpu_array_copy(struct bpf_map * map,void * key,void * value)263 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
264 {
265 	struct bpf_array *array = container_of(map, struct bpf_array, map);
266 	u32 index = *(u32 *)key;
267 	void __percpu *pptr;
268 	int cpu, off = 0;
269 	u32 size;
270 
271 	if (unlikely(index >= array->map.max_entries))
272 		return -ENOENT;
273 
274 	/* per_cpu areas are zero-filled and bpf programs can only
275 	 * access 'value_size' of them, so copying rounded areas
276 	 * will not leak any kernel data
277 	 */
278 	size = array->elem_size;
279 	rcu_read_lock();
280 	pptr = array->pptrs[index & array->index_mask];
281 	for_each_possible_cpu(cpu) {
282 		copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu));
283 		check_and_init_map_value(map, value + off);
284 		off += size;
285 	}
286 	rcu_read_unlock();
287 	return 0;
288 }
289 
290 /* Called from syscall */
array_map_get_next_key(struct bpf_map * map,void * key,void * next_key)291 static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
292 {
293 	struct bpf_array *array = container_of(map, struct bpf_array, map);
294 	u32 index = key ? *(u32 *)key : U32_MAX;
295 	u32 *next = (u32 *)next_key;
296 
297 	if (index >= array->map.max_entries) {
298 		*next = 0;
299 		return 0;
300 	}
301 
302 	if (index == array->map.max_entries - 1)
303 		return -ENOENT;
304 
305 	*next = index + 1;
306 	return 0;
307 }
308 
check_and_free_fields(struct bpf_array * arr,void * val)309 static void check_and_free_fields(struct bpf_array *arr, void *val)
310 {
311 	if (map_value_has_timer(&arr->map))
312 		bpf_timer_cancel_and_free(val + arr->map.timer_off);
313 	if (map_value_has_kptrs(&arr->map))
314 		bpf_map_free_kptrs(&arr->map, val);
315 }
316 
317 /* Called from syscall or from eBPF program */
array_map_update_elem(struct bpf_map * map,void * key,void * value,u64 map_flags)318 static int array_map_update_elem(struct bpf_map *map, void *key, void *value,
319 				 u64 map_flags)
320 {
321 	struct bpf_array *array = container_of(map, struct bpf_array, map);
322 	u32 index = *(u32 *)key;
323 	char *val;
324 
325 	if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
326 		/* unknown flags */
327 		return -EINVAL;
328 
329 	if (unlikely(index >= array->map.max_entries))
330 		/* all elements were pre-allocated, cannot insert a new one */
331 		return -E2BIG;
332 
333 	if (unlikely(map_flags & BPF_NOEXIST))
334 		/* all elements already exist */
335 		return -EEXIST;
336 
337 	if (unlikely((map_flags & BPF_F_LOCK) &&
338 		     !map_value_has_spin_lock(map)))
339 		return -EINVAL;
340 
341 	if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
342 		val = this_cpu_ptr(array->pptrs[index & array->index_mask]);
343 		copy_map_value(map, val, value);
344 		check_and_free_fields(array, val);
345 	} else {
346 		val = array->value +
347 			(u64)array->elem_size * (index & array->index_mask);
348 		if (map_flags & BPF_F_LOCK)
349 			copy_map_value_locked(map, val, value, false);
350 		else
351 			copy_map_value(map, val, value);
352 		check_and_free_fields(array, val);
353 	}
354 	return 0;
355 }
356 
bpf_percpu_array_update(struct bpf_map * map,void * key,void * value,u64 map_flags)357 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
358 			    u64 map_flags)
359 {
360 	struct bpf_array *array = container_of(map, struct bpf_array, map);
361 	u32 index = *(u32 *)key;
362 	void __percpu *pptr;
363 	int cpu, off = 0;
364 	u32 size;
365 
366 	if (unlikely(map_flags > BPF_EXIST))
367 		/* unknown flags */
368 		return -EINVAL;
369 
370 	if (unlikely(index >= array->map.max_entries))
371 		/* all elements were pre-allocated, cannot insert a new one */
372 		return -E2BIG;
373 
374 	if (unlikely(map_flags == BPF_NOEXIST))
375 		/* all elements already exist */
376 		return -EEXIST;
377 
378 	/* the user space will provide round_up(value_size, 8) bytes that
379 	 * will be copied into per-cpu area. bpf programs can only access
380 	 * value_size of it. During lookup the same extra bytes will be
381 	 * returned or zeros which were zero-filled by percpu_alloc,
382 	 * so no kernel data leaks possible
383 	 */
384 	size = array->elem_size;
385 	rcu_read_lock();
386 	pptr = array->pptrs[index & array->index_mask];
387 	for_each_possible_cpu(cpu) {
388 		copy_map_value_long(map, per_cpu_ptr(pptr, cpu), value + off);
389 		check_and_free_fields(array, per_cpu_ptr(pptr, cpu));
390 		off += size;
391 	}
392 	rcu_read_unlock();
393 	return 0;
394 }
395 
396 /* Called from syscall or from eBPF program */
array_map_delete_elem(struct bpf_map * map,void * key)397 static int array_map_delete_elem(struct bpf_map *map, void *key)
398 {
399 	return -EINVAL;
400 }
401 
array_map_vmalloc_addr(struct bpf_array * array)402 static void *array_map_vmalloc_addr(struct bpf_array *array)
403 {
404 	return (void *)round_down((unsigned long)array, PAGE_SIZE);
405 }
406 
array_map_free_timers(struct bpf_map * map)407 static void array_map_free_timers(struct bpf_map *map)
408 {
409 	struct bpf_array *array = container_of(map, struct bpf_array, map);
410 	int i;
411 
412 	/* We don't reset or free kptr on uref dropping to zero. */
413 	if (!map_value_has_timer(map))
414 		return;
415 
416 	for (i = 0; i < array->map.max_entries; i++)
417 		bpf_timer_cancel_and_free(array_map_elem_ptr(array, i) + map->timer_off);
418 }
419 
420 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
array_map_free(struct bpf_map * map)421 static void array_map_free(struct bpf_map *map)
422 {
423 	struct bpf_array *array = container_of(map, struct bpf_array, map);
424 	int i;
425 
426 	if (map_value_has_kptrs(map)) {
427 		if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
428 			for (i = 0; i < array->map.max_entries; i++) {
429 				void __percpu *pptr = array->pptrs[i & array->index_mask];
430 				int cpu;
431 
432 				for_each_possible_cpu(cpu) {
433 					bpf_map_free_kptrs(map, per_cpu_ptr(pptr, cpu));
434 					cond_resched();
435 				}
436 			}
437 		} else {
438 			for (i = 0; i < array->map.max_entries; i++)
439 				bpf_map_free_kptrs(map, array_map_elem_ptr(array, i));
440 		}
441 		bpf_map_free_kptr_off_tab(map);
442 	}
443 
444 	if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
445 		bpf_array_free_percpu(array);
446 
447 	if (array->map.map_flags & BPF_F_MMAPABLE)
448 		bpf_map_area_free(array_map_vmalloc_addr(array));
449 	else
450 		bpf_map_area_free(array);
451 }
452 
array_map_seq_show_elem(struct bpf_map * map,void * key,struct seq_file * m)453 static void array_map_seq_show_elem(struct bpf_map *map, void *key,
454 				    struct seq_file *m)
455 {
456 	void *value;
457 
458 	rcu_read_lock();
459 
460 	value = array_map_lookup_elem(map, key);
461 	if (!value) {
462 		rcu_read_unlock();
463 		return;
464 	}
465 
466 	if (map->btf_key_type_id)
467 		seq_printf(m, "%u: ", *(u32 *)key);
468 	btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
469 	seq_puts(m, "\n");
470 
471 	rcu_read_unlock();
472 }
473 
percpu_array_map_seq_show_elem(struct bpf_map * map,void * key,struct seq_file * m)474 static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
475 					   struct seq_file *m)
476 {
477 	struct bpf_array *array = container_of(map, struct bpf_array, map);
478 	u32 index = *(u32 *)key;
479 	void __percpu *pptr;
480 	int cpu;
481 
482 	rcu_read_lock();
483 
484 	seq_printf(m, "%u: {\n", *(u32 *)key);
485 	pptr = array->pptrs[index & array->index_mask];
486 	for_each_possible_cpu(cpu) {
487 		seq_printf(m, "\tcpu%d: ", cpu);
488 		btf_type_seq_show(map->btf, map->btf_value_type_id,
489 				  per_cpu_ptr(pptr, cpu), m);
490 		seq_puts(m, "\n");
491 	}
492 	seq_puts(m, "}\n");
493 
494 	rcu_read_unlock();
495 }
496 
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)497 static int array_map_check_btf(const struct bpf_map *map,
498 			       const struct btf *btf,
499 			       const struct btf_type *key_type,
500 			       const struct btf_type *value_type)
501 {
502 	u32 int_data;
503 
504 	/* One exception for keyless BTF: .bss/.data/.rodata map */
505 	if (btf_type_is_void(key_type)) {
506 		if (map->map_type != BPF_MAP_TYPE_ARRAY ||
507 		    map->max_entries != 1)
508 			return -EINVAL;
509 
510 		if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
511 			return -EINVAL;
512 
513 		return 0;
514 	}
515 
516 	if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
517 		return -EINVAL;
518 
519 	int_data = *(u32 *)(key_type + 1);
520 	/* bpf array can only take a u32 key. This check makes sure
521 	 * that the btf matches the attr used during map_create.
522 	 */
523 	if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
524 		return -EINVAL;
525 
526 	return 0;
527 }
528 
array_map_mmap(struct bpf_map * map,struct vm_area_struct * vma)529 static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
530 {
531 	struct bpf_array *array = container_of(map, struct bpf_array, map);
532 	pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
533 
534 	if (!(map->map_flags & BPF_F_MMAPABLE))
535 		return -EINVAL;
536 
537 	if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
538 	    PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
539 		return -EINVAL;
540 
541 	return remap_vmalloc_range(vma, array_map_vmalloc_addr(array),
542 				   vma->vm_pgoff + pgoff);
543 }
544 
array_map_meta_equal(const struct bpf_map * meta0,const struct bpf_map * meta1)545 static bool array_map_meta_equal(const struct bpf_map *meta0,
546 				 const struct bpf_map *meta1)
547 {
548 	if (!bpf_map_meta_equal(meta0, meta1))
549 		return false;
550 	return meta0->map_flags & BPF_F_INNER_MAP ? true :
551 	       meta0->max_entries == meta1->max_entries;
552 }
553 
554 struct bpf_iter_seq_array_map_info {
555 	struct bpf_map *map;
556 	void *percpu_value_buf;
557 	u32 index;
558 };
559 
bpf_array_map_seq_start(struct seq_file * seq,loff_t * pos)560 static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
561 {
562 	struct bpf_iter_seq_array_map_info *info = seq->private;
563 	struct bpf_map *map = info->map;
564 	struct bpf_array *array;
565 	u32 index;
566 
567 	if (info->index >= map->max_entries)
568 		return NULL;
569 
570 	if (*pos == 0)
571 		++*pos;
572 	array = container_of(map, struct bpf_array, map);
573 	index = info->index & array->index_mask;
574 	if (info->percpu_value_buf)
575 	       return array->pptrs[index];
576 	return array_map_elem_ptr(array, index);
577 }
578 
bpf_array_map_seq_next(struct seq_file * seq,void * v,loff_t * pos)579 static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
580 {
581 	struct bpf_iter_seq_array_map_info *info = seq->private;
582 	struct bpf_map *map = info->map;
583 	struct bpf_array *array;
584 	u32 index;
585 
586 	++*pos;
587 	++info->index;
588 	if (info->index >= map->max_entries)
589 		return NULL;
590 
591 	array = container_of(map, struct bpf_array, map);
592 	index = info->index & array->index_mask;
593 	if (info->percpu_value_buf)
594 	       return array->pptrs[index];
595 	return array_map_elem_ptr(array, index);
596 }
597 
__bpf_array_map_seq_show(struct seq_file * seq,void * v)598 static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
599 {
600 	struct bpf_iter_seq_array_map_info *info = seq->private;
601 	struct bpf_iter__bpf_map_elem ctx = {};
602 	struct bpf_map *map = info->map;
603 	struct bpf_array *array = container_of(map, struct bpf_array, map);
604 	struct bpf_iter_meta meta;
605 	struct bpf_prog *prog;
606 	int off = 0, cpu = 0;
607 	void __percpu **pptr;
608 	u32 size;
609 
610 	meta.seq = seq;
611 	prog = bpf_iter_get_info(&meta, v == NULL);
612 	if (!prog)
613 		return 0;
614 
615 	ctx.meta = &meta;
616 	ctx.map = info->map;
617 	if (v) {
618 		ctx.key = &info->index;
619 
620 		if (!info->percpu_value_buf) {
621 			ctx.value = v;
622 		} else {
623 			pptr = v;
624 			size = array->elem_size;
625 			for_each_possible_cpu(cpu) {
626 				copy_map_value_long(map, info->percpu_value_buf + off,
627 						    per_cpu_ptr(pptr, cpu));
628 				check_and_init_map_value(map, info->percpu_value_buf + off);
629 				off += size;
630 			}
631 			ctx.value = info->percpu_value_buf;
632 		}
633 	}
634 
635 	return bpf_iter_run_prog(prog, &ctx);
636 }
637 
bpf_array_map_seq_show(struct seq_file * seq,void * v)638 static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
639 {
640 	return __bpf_array_map_seq_show(seq, v);
641 }
642 
bpf_array_map_seq_stop(struct seq_file * seq,void * v)643 static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
644 {
645 	if (!v)
646 		(void)__bpf_array_map_seq_show(seq, NULL);
647 }
648 
bpf_iter_init_array_map(void * priv_data,struct bpf_iter_aux_info * aux)649 static int bpf_iter_init_array_map(void *priv_data,
650 				   struct bpf_iter_aux_info *aux)
651 {
652 	struct bpf_iter_seq_array_map_info *seq_info = priv_data;
653 	struct bpf_map *map = aux->map;
654 	struct bpf_array *array = container_of(map, struct bpf_array, map);
655 	void *value_buf;
656 	u32 buf_size;
657 
658 	if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
659 		buf_size = array->elem_size * num_possible_cpus();
660 		value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
661 		if (!value_buf)
662 			return -ENOMEM;
663 
664 		seq_info->percpu_value_buf = value_buf;
665 	}
666 
667 	/* bpf_iter_attach_map() acquires a map uref, and the uref may be
668 	 * released before or in the middle of iterating map elements, so
669 	 * acquire an extra map uref for iterator.
670 	 */
671 	bpf_map_inc_with_uref(map);
672 	seq_info->map = map;
673 	return 0;
674 }
675 
bpf_iter_fini_array_map(void * priv_data)676 static void bpf_iter_fini_array_map(void *priv_data)
677 {
678 	struct bpf_iter_seq_array_map_info *seq_info = priv_data;
679 
680 	bpf_map_put_with_uref(seq_info->map);
681 	kfree(seq_info->percpu_value_buf);
682 }
683 
684 static const struct seq_operations bpf_array_map_seq_ops = {
685 	.start	= bpf_array_map_seq_start,
686 	.next	= bpf_array_map_seq_next,
687 	.stop	= bpf_array_map_seq_stop,
688 	.show	= bpf_array_map_seq_show,
689 };
690 
691 static const struct bpf_iter_seq_info iter_seq_info = {
692 	.seq_ops		= &bpf_array_map_seq_ops,
693 	.init_seq_private	= bpf_iter_init_array_map,
694 	.fini_seq_private	= bpf_iter_fini_array_map,
695 	.seq_priv_size		= sizeof(struct bpf_iter_seq_array_map_info),
696 };
697 
bpf_for_each_array_elem(struct bpf_map * map,bpf_callback_t callback_fn,void * callback_ctx,u64 flags)698 static int bpf_for_each_array_elem(struct bpf_map *map, bpf_callback_t callback_fn,
699 				   void *callback_ctx, u64 flags)
700 {
701 	u32 i, key, num_elems = 0;
702 	struct bpf_array *array;
703 	bool is_percpu;
704 	u64 ret = 0;
705 	void *val;
706 
707 	if (flags != 0)
708 		return -EINVAL;
709 
710 	is_percpu = map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
711 	array = container_of(map, struct bpf_array, map);
712 	if (is_percpu)
713 		migrate_disable();
714 	for (i = 0; i < map->max_entries; i++) {
715 		if (is_percpu)
716 			val = this_cpu_ptr(array->pptrs[i]);
717 		else
718 			val = array_map_elem_ptr(array, i);
719 		num_elems++;
720 		key = i;
721 		ret = callback_fn((u64)(long)map, (u64)(long)&key,
722 				  (u64)(long)val, (u64)(long)callback_ctx, 0);
723 		/* return value: 0 - continue, 1 - stop and return */
724 		if (ret)
725 			break;
726 	}
727 
728 	if (is_percpu)
729 		migrate_enable();
730 	return num_elems;
731 }
732 
733 BTF_ID_LIST_SINGLE(array_map_btf_ids, struct, bpf_array)
734 const struct bpf_map_ops array_map_ops = {
735 	.map_meta_equal = array_map_meta_equal,
736 	.map_alloc_check = array_map_alloc_check,
737 	.map_alloc = array_map_alloc,
738 	.map_free = array_map_free,
739 	.map_get_next_key = array_map_get_next_key,
740 	.map_release_uref = array_map_free_timers,
741 	.map_lookup_elem = array_map_lookup_elem,
742 	.map_update_elem = array_map_update_elem,
743 	.map_delete_elem = array_map_delete_elem,
744 	.map_gen_lookup = array_map_gen_lookup,
745 	.map_direct_value_addr = array_map_direct_value_addr,
746 	.map_direct_value_meta = array_map_direct_value_meta,
747 	.map_mmap = array_map_mmap,
748 	.map_seq_show_elem = array_map_seq_show_elem,
749 	.map_check_btf = array_map_check_btf,
750 	.map_lookup_batch = generic_map_lookup_batch,
751 	.map_update_batch = generic_map_update_batch,
752 	.map_set_for_each_callback_args = map_set_for_each_callback_args,
753 	.map_for_each_callback = bpf_for_each_array_elem,
754 	.map_btf_id = &array_map_btf_ids[0],
755 	.iter_seq_info = &iter_seq_info,
756 };
757 
758 const struct bpf_map_ops percpu_array_map_ops = {
759 	.map_meta_equal = bpf_map_meta_equal,
760 	.map_alloc_check = array_map_alloc_check,
761 	.map_alloc = array_map_alloc,
762 	.map_free = array_map_free,
763 	.map_get_next_key = array_map_get_next_key,
764 	.map_lookup_elem = percpu_array_map_lookup_elem,
765 	.map_update_elem = array_map_update_elem,
766 	.map_delete_elem = array_map_delete_elem,
767 	.map_lookup_percpu_elem = percpu_array_map_lookup_percpu_elem,
768 	.map_seq_show_elem = percpu_array_map_seq_show_elem,
769 	.map_check_btf = array_map_check_btf,
770 	.map_lookup_batch = generic_map_lookup_batch,
771 	.map_update_batch = generic_map_update_batch,
772 	.map_set_for_each_callback_args = map_set_for_each_callback_args,
773 	.map_for_each_callback = bpf_for_each_array_elem,
774 	.map_btf_id = &array_map_btf_ids[0],
775 	.iter_seq_info = &iter_seq_info,
776 };
777 
fd_array_map_alloc_check(union bpf_attr * attr)778 static int fd_array_map_alloc_check(union bpf_attr *attr)
779 {
780 	/* only file descriptors can be stored in this type of map */
781 	if (attr->value_size != sizeof(u32))
782 		return -EINVAL;
783 	/* Program read-only/write-only not supported for special maps yet. */
784 	if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
785 		return -EINVAL;
786 	return array_map_alloc_check(attr);
787 }
788 
fd_array_map_free(struct bpf_map * map)789 static void fd_array_map_free(struct bpf_map *map)
790 {
791 	struct bpf_array *array = container_of(map, struct bpf_array, map);
792 	int i;
793 
794 	/* make sure it's empty */
795 	for (i = 0; i < array->map.max_entries; i++)
796 		BUG_ON(array->ptrs[i] != NULL);
797 
798 	bpf_map_area_free(array);
799 }
800 
fd_array_map_lookup_elem(struct bpf_map * map,void * key)801 static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
802 {
803 	return ERR_PTR(-EOPNOTSUPP);
804 }
805 
806 /* only called from syscall */
bpf_fd_array_map_lookup_elem(struct bpf_map * map,void * key,u32 * value)807 int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
808 {
809 	void **elem, *ptr;
810 	int ret =  0;
811 
812 	if (!map->ops->map_fd_sys_lookup_elem)
813 		return -ENOTSUPP;
814 
815 	rcu_read_lock();
816 	elem = array_map_lookup_elem(map, key);
817 	if (elem && (ptr = READ_ONCE(*elem)))
818 		*value = map->ops->map_fd_sys_lookup_elem(ptr);
819 	else
820 		ret = -ENOENT;
821 	rcu_read_unlock();
822 
823 	return ret;
824 }
825 
826 /* only called from syscall */
bpf_fd_array_map_update_elem(struct bpf_map * map,struct file * map_file,void * key,void * value,u64 map_flags)827 int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
828 				 void *key, void *value, u64 map_flags)
829 {
830 	struct bpf_array *array = container_of(map, struct bpf_array, map);
831 	void *new_ptr, *old_ptr;
832 	u32 index = *(u32 *)key, ufd;
833 
834 	if (map_flags != BPF_ANY)
835 		return -EINVAL;
836 
837 	if (index >= array->map.max_entries)
838 		return -E2BIG;
839 
840 	ufd = *(u32 *)value;
841 	new_ptr = map->ops->map_fd_get_ptr(map, map_file, ufd);
842 	if (IS_ERR(new_ptr))
843 		return PTR_ERR(new_ptr);
844 
845 	if (map->ops->map_poke_run) {
846 		mutex_lock(&array->aux->poke_mutex);
847 		old_ptr = xchg(array->ptrs + index, new_ptr);
848 		map->ops->map_poke_run(map, index, old_ptr, new_ptr);
849 		mutex_unlock(&array->aux->poke_mutex);
850 	} else {
851 		old_ptr = xchg(array->ptrs + index, new_ptr);
852 	}
853 
854 	if (old_ptr)
855 		map->ops->map_fd_put_ptr(old_ptr);
856 	return 0;
857 }
858 
fd_array_map_delete_elem(struct bpf_map * map,void * key)859 static int fd_array_map_delete_elem(struct bpf_map *map, void *key)
860 {
861 	struct bpf_array *array = container_of(map, struct bpf_array, map);
862 	void *old_ptr;
863 	u32 index = *(u32 *)key;
864 
865 	if (index >= array->map.max_entries)
866 		return -E2BIG;
867 
868 	if (map->ops->map_poke_run) {
869 		mutex_lock(&array->aux->poke_mutex);
870 		old_ptr = xchg(array->ptrs + index, NULL);
871 		map->ops->map_poke_run(map, index, old_ptr, NULL);
872 		mutex_unlock(&array->aux->poke_mutex);
873 	} else {
874 		old_ptr = xchg(array->ptrs + index, NULL);
875 	}
876 
877 	if (old_ptr) {
878 		map->ops->map_fd_put_ptr(old_ptr);
879 		return 0;
880 	} else {
881 		return -ENOENT;
882 	}
883 }
884 
prog_fd_array_get_ptr(struct bpf_map * map,struct file * map_file,int fd)885 static void *prog_fd_array_get_ptr(struct bpf_map *map,
886 				   struct file *map_file, int fd)
887 {
888 	struct bpf_prog *prog = bpf_prog_get(fd);
889 
890 	if (IS_ERR(prog))
891 		return prog;
892 
893 	if (!bpf_prog_map_compatible(map, prog)) {
894 		bpf_prog_put(prog);
895 		return ERR_PTR(-EINVAL);
896 	}
897 
898 	return prog;
899 }
900 
prog_fd_array_put_ptr(void * ptr)901 static void prog_fd_array_put_ptr(void *ptr)
902 {
903 	bpf_prog_put(ptr);
904 }
905 
prog_fd_array_sys_lookup_elem(void * ptr)906 static u32 prog_fd_array_sys_lookup_elem(void *ptr)
907 {
908 	return ((struct bpf_prog *)ptr)->aux->id;
909 }
910 
911 /* decrement refcnt of all bpf_progs that are stored in this map */
bpf_fd_array_map_clear(struct bpf_map * map)912 static void bpf_fd_array_map_clear(struct bpf_map *map)
913 {
914 	struct bpf_array *array = container_of(map, struct bpf_array, map);
915 	int i;
916 
917 	for (i = 0; i < array->map.max_entries; i++)
918 		fd_array_map_delete_elem(map, &i);
919 }
920 
prog_array_map_seq_show_elem(struct bpf_map * map,void * key,struct seq_file * m)921 static void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
922 					 struct seq_file *m)
923 {
924 	void **elem, *ptr;
925 	u32 prog_id;
926 
927 	rcu_read_lock();
928 
929 	elem = array_map_lookup_elem(map, key);
930 	if (elem) {
931 		ptr = READ_ONCE(*elem);
932 		if (ptr) {
933 			seq_printf(m, "%u: ", *(u32 *)key);
934 			prog_id = prog_fd_array_sys_lookup_elem(ptr);
935 			btf_type_seq_show(map->btf, map->btf_value_type_id,
936 					  &prog_id, m);
937 			seq_puts(m, "\n");
938 		}
939 	}
940 
941 	rcu_read_unlock();
942 }
943 
944 struct prog_poke_elem {
945 	struct list_head list;
946 	struct bpf_prog_aux *aux;
947 };
948 
prog_array_map_poke_track(struct bpf_map * map,struct bpf_prog_aux * prog_aux)949 static int prog_array_map_poke_track(struct bpf_map *map,
950 				     struct bpf_prog_aux *prog_aux)
951 {
952 	struct prog_poke_elem *elem;
953 	struct bpf_array_aux *aux;
954 	int ret = 0;
955 
956 	aux = container_of(map, struct bpf_array, map)->aux;
957 	mutex_lock(&aux->poke_mutex);
958 	list_for_each_entry(elem, &aux->poke_progs, list) {
959 		if (elem->aux == prog_aux)
960 			goto out;
961 	}
962 
963 	elem = kmalloc(sizeof(*elem), GFP_KERNEL);
964 	if (!elem) {
965 		ret = -ENOMEM;
966 		goto out;
967 	}
968 
969 	INIT_LIST_HEAD(&elem->list);
970 	/* We must track the program's aux info at this point in time
971 	 * since the program pointer itself may not be stable yet, see
972 	 * also comment in prog_array_map_poke_run().
973 	 */
974 	elem->aux = prog_aux;
975 
976 	list_add_tail(&elem->list, &aux->poke_progs);
977 out:
978 	mutex_unlock(&aux->poke_mutex);
979 	return ret;
980 }
981 
prog_array_map_poke_untrack(struct bpf_map * map,struct bpf_prog_aux * prog_aux)982 static void prog_array_map_poke_untrack(struct bpf_map *map,
983 					struct bpf_prog_aux *prog_aux)
984 {
985 	struct prog_poke_elem *elem, *tmp;
986 	struct bpf_array_aux *aux;
987 
988 	aux = container_of(map, struct bpf_array, map)->aux;
989 	mutex_lock(&aux->poke_mutex);
990 	list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
991 		if (elem->aux == prog_aux) {
992 			list_del_init(&elem->list);
993 			kfree(elem);
994 			break;
995 		}
996 	}
997 	mutex_unlock(&aux->poke_mutex);
998 }
999 
prog_array_map_poke_run(struct bpf_map * map,u32 key,struct bpf_prog * old,struct bpf_prog * new)1000 static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
1001 				    struct bpf_prog *old,
1002 				    struct bpf_prog *new)
1003 {
1004 	u8 *old_addr, *new_addr, *old_bypass_addr;
1005 	struct prog_poke_elem *elem;
1006 	struct bpf_array_aux *aux;
1007 
1008 	aux = container_of(map, struct bpf_array, map)->aux;
1009 	WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
1010 
1011 	list_for_each_entry(elem, &aux->poke_progs, list) {
1012 		struct bpf_jit_poke_descriptor *poke;
1013 		int i, ret;
1014 
1015 		for (i = 0; i < elem->aux->size_poke_tab; i++) {
1016 			poke = &elem->aux->poke_tab[i];
1017 
1018 			/* Few things to be aware of:
1019 			 *
1020 			 * 1) We can only ever access aux in this context, but
1021 			 *    not aux->prog since it might not be stable yet and
1022 			 *    there could be danger of use after free otherwise.
1023 			 * 2) Initially when we start tracking aux, the program
1024 			 *    is not JITed yet and also does not have a kallsyms
1025 			 *    entry. We skip these as poke->tailcall_target_stable
1026 			 *    is not active yet. The JIT will do the final fixup
1027 			 *    before setting it stable. The various
1028 			 *    poke->tailcall_target_stable are successively
1029 			 *    activated, so tail call updates can arrive from here
1030 			 *    while JIT is still finishing its final fixup for
1031 			 *    non-activated poke entries.
1032 			 * 3) On program teardown, the program's kallsym entry gets
1033 			 *    removed out of RCU callback, but we can only untrack
1034 			 *    from sleepable context, therefore bpf_arch_text_poke()
1035 			 *    might not see that this is in BPF text section and
1036 			 *    bails out with -EINVAL. As these are unreachable since
1037 			 *    RCU grace period already passed, we simply skip them.
1038 			 * 4) Also programs reaching refcount of zero while patching
1039 			 *    is in progress is okay since we're protected under
1040 			 *    poke_mutex and untrack the programs before the JIT
1041 			 *    buffer is freed. When we're still in the middle of
1042 			 *    patching and suddenly kallsyms entry of the program
1043 			 *    gets evicted, we just skip the rest which is fine due
1044 			 *    to point 3).
1045 			 * 5) Any other error happening below from bpf_arch_text_poke()
1046 			 *    is a unexpected bug.
1047 			 */
1048 			if (!READ_ONCE(poke->tailcall_target_stable))
1049 				continue;
1050 			if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
1051 				continue;
1052 			if (poke->tail_call.map != map ||
1053 			    poke->tail_call.key != key)
1054 				continue;
1055 
1056 			old_bypass_addr = old ? NULL : poke->bypass_addr;
1057 			old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
1058 			new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
1059 
1060 			if (new) {
1061 				ret = bpf_arch_text_poke(poke->tailcall_target,
1062 							 BPF_MOD_JUMP,
1063 							 old_addr, new_addr);
1064 				BUG_ON(ret < 0 && ret != -EINVAL);
1065 				if (!old) {
1066 					ret = bpf_arch_text_poke(poke->tailcall_bypass,
1067 								 BPF_MOD_JUMP,
1068 								 poke->bypass_addr,
1069 								 NULL);
1070 					BUG_ON(ret < 0 && ret != -EINVAL);
1071 				}
1072 			} else {
1073 				ret = bpf_arch_text_poke(poke->tailcall_bypass,
1074 							 BPF_MOD_JUMP,
1075 							 old_bypass_addr,
1076 							 poke->bypass_addr);
1077 				BUG_ON(ret < 0 && ret != -EINVAL);
1078 				/* let other CPUs finish the execution of program
1079 				 * so that it will not possible to expose them
1080 				 * to invalid nop, stack unwind, nop state
1081 				 */
1082 				if (!ret)
1083 					synchronize_rcu();
1084 				ret = bpf_arch_text_poke(poke->tailcall_target,
1085 							 BPF_MOD_JUMP,
1086 							 old_addr, NULL);
1087 				BUG_ON(ret < 0 && ret != -EINVAL);
1088 			}
1089 		}
1090 	}
1091 }
1092 
prog_array_map_clear_deferred(struct work_struct * work)1093 static void prog_array_map_clear_deferred(struct work_struct *work)
1094 {
1095 	struct bpf_map *map = container_of(work, struct bpf_array_aux,
1096 					   work)->map;
1097 	bpf_fd_array_map_clear(map);
1098 	bpf_map_put(map);
1099 }
1100 
prog_array_map_clear(struct bpf_map * map)1101 static void prog_array_map_clear(struct bpf_map *map)
1102 {
1103 	struct bpf_array_aux *aux = container_of(map, struct bpf_array,
1104 						 map)->aux;
1105 	bpf_map_inc(map);
1106 	schedule_work(&aux->work);
1107 }
1108 
prog_array_map_alloc(union bpf_attr * attr)1109 static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
1110 {
1111 	struct bpf_array_aux *aux;
1112 	struct bpf_map *map;
1113 
1114 	aux = kzalloc(sizeof(*aux), GFP_KERNEL_ACCOUNT);
1115 	if (!aux)
1116 		return ERR_PTR(-ENOMEM);
1117 
1118 	INIT_WORK(&aux->work, prog_array_map_clear_deferred);
1119 	INIT_LIST_HEAD(&aux->poke_progs);
1120 	mutex_init(&aux->poke_mutex);
1121 
1122 	map = array_map_alloc(attr);
1123 	if (IS_ERR(map)) {
1124 		kfree(aux);
1125 		return map;
1126 	}
1127 
1128 	container_of(map, struct bpf_array, map)->aux = aux;
1129 	aux->map = map;
1130 
1131 	return map;
1132 }
1133 
prog_array_map_free(struct bpf_map * map)1134 static void prog_array_map_free(struct bpf_map *map)
1135 {
1136 	struct prog_poke_elem *elem, *tmp;
1137 	struct bpf_array_aux *aux;
1138 
1139 	aux = container_of(map, struct bpf_array, map)->aux;
1140 	list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
1141 		list_del_init(&elem->list);
1142 		kfree(elem);
1143 	}
1144 	kfree(aux);
1145 	fd_array_map_free(map);
1146 }
1147 
1148 /* prog_array->aux->{type,jited} is a runtime binding.
1149  * Doing static check alone in the verifier is not enough.
1150  * Thus, prog_array_map cannot be used as an inner_map
1151  * and map_meta_equal is not implemented.
1152  */
1153 const struct bpf_map_ops prog_array_map_ops = {
1154 	.map_alloc_check = fd_array_map_alloc_check,
1155 	.map_alloc = prog_array_map_alloc,
1156 	.map_free = prog_array_map_free,
1157 	.map_poke_track = prog_array_map_poke_track,
1158 	.map_poke_untrack = prog_array_map_poke_untrack,
1159 	.map_poke_run = prog_array_map_poke_run,
1160 	.map_get_next_key = array_map_get_next_key,
1161 	.map_lookup_elem = fd_array_map_lookup_elem,
1162 	.map_delete_elem = fd_array_map_delete_elem,
1163 	.map_fd_get_ptr = prog_fd_array_get_ptr,
1164 	.map_fd_put_ptr = prog_fd_array_put_ptr,
1165 	.map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
1166 	.map_release_uref = prog_array_map_clear,
1167 	.map_seq_show_elem = prog_array_map_seq_show_elem,
1168 	.map_btf_id = &array_map_btf_ids[0],
1169 };
1170 
bpf_event_entry_gen(struct file * perf_file,struct file * map_file)1171 static struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
1172 						   struct file *map_file)
1173 {
1174 	struct bpf_event_entry *ee;
1175 
1176 	ee = kzalloc(sizeof(*ee), GFP_ATOMIC);
1177 	if (ee) {
1178 		ee->event = perf_file->private_data;
1179 		ee->perf_file = perf_file;
1180 		ee->map_file = map_file;
1181 	}
1182 
1183 	return ee;
1184 }
1185 
__bpf_event_entry_free(struct rcu_head * rcu)1186 static void __bpf_event_entry_free(struct rcu_head *rcu)
1187 {
1188 	struct bpf_event_entry *ee;
1189 
1190 	ee = container_of(rcu, struct bpf_event_entry, rcu);
1191 	fput(ee->perf_file);
1192 	kfree(ee);
1193 }
1194 
bpf_event_entry_free_rcu(struct bpf_event_entry * ee)1195 static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
1196 {
1197 	call_rcu(&ee->rcu, __bpf_event_entry_free);
1198 }
1199 
perf_event_fd_array_get_ptr(struct bpf_map * map,struct file * map_file,int fd)1200 static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
1201 					 struct file *map_file, int fd)
1202 {
1203 	struct bpf_event_entry *ee;
1204 	struct perf_event *event;
1205 	struct file *perf_file;
1206 	u64 value;
1207 
1208 	perf_file = perf_event_get(fd);
1209 	if (IS_ERR(perf_file))
1210 		return perf_file;
1211 
1212 	ee = ERR_PTR(-EOPNOTSUPP);
1213 	event = perf_file->private_data;
1214 	if (perf_event_read_local(event, &value, NULL, NULL) == -EOPNOTSUPP)
1215 		goto err_out;
1216 
1217 	ee = bpf_event_entry_gen(perf_file, map_file);
1218 	if (ee)
1219 		return ee;
1220 	ee = ERR_PTR(-ENOMEM);
1221 err_out:
1222 	fput(perf_file);
1223 	return ee;
1224 }
1225 
perf_event_fd_array_put_ptr(void * ptr)1226 static void perf_event_fd_array_put_ptr(void *ptr)
1227 {
1228 	bpf_event_entry_free_rcu(ptr);
1229 }
1230 
perf_event_fd_array_release(struct bpf_map * map,struct file * map_file)1231 static void perf_event_fd_array_release(struct bpf_map *map,
1232 					struct file *map_file)
1233 {
1234 	struct bpf_array *array = container_of(map, struct bpf_array, map);
1235 	struct bpf_event_entry *ee;
1236 	int i;
1237 
1238 	if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1239 		return;
1240 
1241 	rcu_read_lock();
1242 	for (i = 0; i < array->map.max_entries; i++) {
1243 		ee = READ_ONCE(array->ptrs[i]);
1244 		if (ee && ee->map_file == map_file)
1245 			fd_array_map_delete_elem(map, &i);
1246 	}
1247 	rcu_read_unlock();
1248 }
1249 
perf_event_fd_array_map_free(struct bpf_map * map)1250 static void perf_event_fd_array_map_free(struct bpf_map *map)
1251 {
1252 	if (map->map_flags & BPF_F_PRESERVE_ELEMS)
1253 		bpf_fd_array_map_clear(map);
1254 	fd_array_map_free(map);
1255 }
1256 
1257 const struct bpf_map_ops perf_event_array_map_ops = {
1258 	.map_meta_equal = bpf_map_meta_equal,
1259 	.map_alloc_check = fd_array_map_alloc_check,
1260 	.map_alloc = array_map_alloc,
1261 	.map_free = perf_event_fd_array_map_free,
1262 	.map_get_next_key = array_map_get_next_key,
1263 	.map_lookup_elem = fd_array_map_lookup_elem,
1264 	.map_delete_elem = fd_array_map_delete_elem,
1265 	.map_fd_get_ptr = perf_event_fd_array_get_ptr,
1266 	.map_fd_put_ptr = perf_event_fd_array_put_ptr,
1267 	.map_release = perf_event_fd_array_release,
1268 	.map_check_btf = map_check_no_btf,
1269 	.map_btf_id = &array_map_btf_ids[0],
1270 };
1271 
1272 #ifdef CONFIG_CGROUPS
cgroup_fd_array_get_ptr(struct bpf_map * map,struct file * map_file,int fd)1273 static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
1274 				     struct file *map_file /* not used */,
1275 				     int fd)
1276 {
1277 	return cgroup_get_from_fd(fd);
1278 }
1279 
cgroup_fd_array_put_ptr(void * ptr)1280 static void cgroup_fd_array_put_ptr(void *ptr)
1281 {
1282 	/* cgroup_put free cgrp after a rcu grace period */
1283 	cgroup_put(ptr);
1284 }
1285 
cgroup_fd_array_free(struct bpf_map * map)1286 static void cgroup_fd_array_free(struct bpf_map *map)
1287 {
1288 	bpf_fd_array_map_clear(map);
1289 	fd_array_map_free(map);
1290 }
1291 
1292 const struct bpf_map_ops cgroup_array_map_ops = {
1293 	.map_meta_equal = bpf_map_meta_equal,
1294 	.map_alloc_check = fd_array_map_alloc_check,
1295 	.map_alloc = array_map_alloc,
1296 	.map_free = cgroup_fd_array_free,
1297 	.map_get_next_key = array_map_get_next_key,
1298 	.map_lookup_elem = fd_array_map_lookup_elem,
1299 	.map_delete_elem = fd_array_map_delete_elem,
1300 	.map_fd_get_ptr = cgroup_fd_array_get_ptr,
1301 	.map_fd_put_ptr = cgroup_fd_array_put_ptr,
1302 	.map_check_btf = map_check_no_btf,
1303 	.map_btf_id = &array_map_btf_ids[0],
1304 };
1305 #endif
1306 
array_of_map_alloc(union bpf_attr * attr)1307 static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
1308 {
1309 	struct bpf_map *map, *inner_map_meta;
1310 
1311 	inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
1312 	if (IS_ERR(inner_map_meta))
1313 		return inner_map_meta;
1314 
1315 	map = array_map_alloc(attr);
1316 	if (IS_ERR(map)) {
1317 		bpf_map_meta_free(inner_map_meta);
1318 		return map;
1319 	}
1320 
1321 	map->inner_map_meta = inner_map_meta;
1322 
1323 	return map;
1324 }
1325 
array_of_map_free(struct bpf_map * map)1326 static void array_of_map_free(struct bpf_map *map)
1327 {
1328 	/* map->inner_map_meta is only accessed by syscall which
1329 	 * is protected by fdget/fdput.
1330 	 */
1331 	bpf_map_meta_free(map->inner_map_meta);
1332 	bpf_fd_array_map_clear(map);
1333 	fd_array_map_free(map);
1334 }
1335 
array_of_map_lookup_elem(struct bpf_map * map,void * key)1336 static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
1337 {
1338 	struct bpf_map **inner_map = array_map_lookup_elem(map, key);
1339 
1340 	if (!inner_map)
1341 		return NULL;
1342 
1343 	return READ_ONCE(*inner_map);
1344 }
1345 
array_of_map_gen_lookup(struct bpf_map * map,struct bpf_insn * insn_buf)1346 static int array_of_map_gen_lookup(struct bpf_map *map,
1347 				   struct bpf_insn *insn_buf)
1348 {
1349 	struct bpf_array *array = container_of(map, struct bpf_array, map);
1350 	u32 elem_size = array->elem_size;
1351 	struct bpf_insn *insn = insn_buf;
1352 	const int ret = BPF_REG_0;
1353 	const int map_ptr = BPF_REG_1;
1354 	const int index = BPF_REG_2;
1355 
1356 	*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
1357 	*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
1358 	if (!map->bypass_spec_v1) {
1359 		*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
1360 		*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
1361 	} else {
1362 		*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
1363 	}
1364 	if (is_power_of_2(elem_size))
1365 		*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
1366 	else
1367 		*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
1368 	*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
1369 	*insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
1370 	*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
1371 	*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
1372 	*insn++ = BPF_MOV64_IMM(ret, 0);
1373 
1374 	return insn - insn_buf;
1375 }
1376 
1377 const struct bpf_map_ops array_of_maps_map_ops = {
1378 	.map_alloc_check = fd_array_map_alloc_check,
1379 	.map_alloc = array_of_map_alloc,
1380 	.map_free = array_of_map_free,
1381 	.map_get_next_key = array_map_get_next_key,
1382 	.map_lookup_elem = array_of_map_lookup_elem,
1383 	.map_delete_elem = fd_array_map_delete_elem,
1384 	.map_fd_get_ptr = bpf_map_fd_get_ptr,
1385 	.map_fd_put_ptr = bpf_map_fd_put_ptr,
1386 	.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
1387 	.map_gen_lookup = array_of_map_gen_lookup,
1388 	.map_lookup_batch = generic_map_lookup_batch,
1389 	.map_update_batch = generic_map_update_batch,
1390 	.map_check_btf = map_check_no_btf,
1391 	.map_btf_id = &array_map_btf_ids[0],
1392 };
1393