1 /*
2 * Copyright (C) 2020 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define TLOG_TAG "coverage-common-shm"
18
19 #include <assert.h>
20 #include <lib/coverage/common/cov_shm.h>
21 #include <lk/macros.h>
22 #include <stdlib.h>
23 #include <sys/auxv.h>
24 #include <sys/mman.h>
25 #include <trusty/memref.h>
26 #include <trusty_log.h>
27 #include <uapi/err.h>
28
29 #define PAGE_SIZE getauxval(AT_PAGESZ)
30 #define MMAP_FLAG_PROT_RW (MMAP_FLAG_PROT_READ | MMAP_FLAG_PROT_WRITE)
31
cov_shm_alloc(struct cov_shm * shm,size_t len)32 int cov_shm_alloc(struct cov_shm* shm, size_t len) {
33 int rc;
34 void* base;
35 size_t shm_len;
36
37 shm_len = round_up(len, PAGE_SIZE);
38 base = memalign(PAGE_SIZE, shm_len);
39 if (!base) {
40 TLOGE("failed to allocate %zu bytes of shared memory\n", shm_len);
41 return ERR_NO_MEMORY;
42 }
43
44 rc = memref_create(base, shm_len, MMAP_FLAG_PROT_RW);
45 if (rc < 0) {
46 TLOGE("failed (%d) to create memref\n", rc);
47 free(shm);
48 return rc;
49 }
50
51 shm->memref = (handle_t)rc;
52 shm->base = base;
53 shm->len = shm_len;
54
55 cov_shm_clear(shm);
56 return NO_ERROR;
57 }
58
cov_shm_free(struct cov_shm * shm)59 void cov_shm_free(struct cov_shm* shm) {
60 /*
61 * TODO: HACK: No way to safely deallocate memory that has already been
62 * shared, but works in practice.
63 */
64 free(shm->base);
65 close(shm->memref);
66 shm->memref = INVALID_IPC_HANDLE;
67 shm->base = NULL;
68 shm->len = 0;
69 }
70
cov_shm_mmap(struct cov_shm * shm,handle_t memref,size_t len)71 int cov_shm_mmap(struct cov_shm* shm, handle_t memref, size_t len) {
72 void* base = mmap(0, len, MMAP_FLAG_PROT_RW, 0, memref, 0);
73 if (base == MAP_FAILED) {
74 TLOGE("failed to mmap() shared memory\n");
75 return ERR_BAD_HANDLE;
76 }
77
78 shm->memref = memref;
79 shm->base = base;
80 shm->len = len;
81 return NO_ERROR;
82 }
83
cov_shm_munmap(struct cov_shm * shm)84 void cov_shm_munmap(struct cov_shm* shm) {
85 assert(cov_shm_is_mapped(shm));
86
87 munmap(shm->base, shm->len);
88 close(shm->memref);
89 shm->memref = INVALID_IPC_HANDLE;
90 shm->base = NULL;
91 shm->len = 0;
92 }
93
cov_shm_clear(struct cov_shm * shm)94 void cov_shm_clear(struct cov_shm* shm) {
95 assert(cov_shm_is_mapped(shm));
96
97 for (size_t i = 0; i < shm->len; i++) {
98 WRITE_ONCE(*((uint8_t*)(shm->base) + i), 0);
99 }
100 }
101