mapper.cpp revision bd80b38f2945ac918f66fb336c149b28b9dd030e 
1/*
2 * Copyright (C) 2008 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#include <limits.h>
18#include <errno.h>
19#include <pthread.h>
20#include <unistd.h>
21#include <string.h>
22
23#include <sys/mman.h>
24#include <sys/stat.h>
25#include <sys/types.h>
26
27#include <cutils/log.h>
28#include <cutils/atomic.h>
29
30#include <hardware/hardware.h>
31#include <hardware/gralloc.h>
32
33#include "gralloc_priv.h"
34
35
36// we need this for now because pmem cannot mmap at an offset
37#define PMEM_HACK   1
38
39/* desktop Linux needs a little help with gettid() */
40#if defined(ARCH_X86) && !defined(HAVE_ANDROID_OS)
41#define __KERNEL__
42# include <linux/unistd.h>
43pid_t gettid() { return syscall(__NR_gettid);}
44#undef __KERNEL__
45#endif
46
47/*****************************************************************************/
48
49static int gralloc_map(gralloc_module_t const* module,
50        buffer_handle_t handle,
51        void** vaddr)
52{
53    private_handle_t* hnd = (private_handle_t*)handle;
54    if (!(hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER)) {
55        size_t size = hnd->size;
56#if PMEM_HACK
57        size += hnd->offset;
58#endif
59        void* mappedAddress = mmap(0, size,
60                PROT_READ|PROT_WRITE, MAP_SHARED, hnd->fd, 0);
61        if (mappedAddress == MAP_FAILED) {
62            LOGE("Could not mmap %s", strerror(errno));
63            return -errno;
64        }
65        hnd->base = intptr_t(mappedAddress) + hnd->offset;
66        //LOGD("gralloc_map() succeeded fd=%d, off=%d, size=%d, vaddr=%p",
67        //        hnd->fd, hnd->offset, hnd->size, mappedAddress);
68    }
69    *vaddr = (void*)hnd->base;
70    return 0;
71}
72
73static int gralloc_unmap(gralloc_module_t const* module,
74        buffer_handle_t handle)
75{
76    private_handle_t* hnd = (private_handle_t*)handle;
77    if (!(hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER)) {
78        void* base = (void*)hnd->base;
79        size_t size = hnd->size;
80#if PMEM_HACK
81        base = (void*)(intptr_t(base) - hnd->offset);
82        size += hnd->offset;
83#endif
84        //LOGD("unmapping from %p, size=%d", base, size);
85        if (munmap(base, size) < 0) {
86            LOGE("Could not unmap %s", strerror(errno));
87        }
88    }
89    hnd->base = 0;
90    return 0;
91}
92
93/*****************************************************************************/
94
95static pthread_mutex_t sMapLock = PTHREAD_MUTEX_INITIALIZER;
96
97/*****************************************************************************/
98
99int gralloc_register_buffer(gralloc_module_t const* module,
100        buffer_handle_t handle)
101{
102    if (private_handle_t::validate(handle) < 0)
103        return -EINVAL;
104
105    // In this implementation, we don't need to do anything here
106
107    /* NOTE: we need to initialize the buffer as not mapped/not locked
108     * because it shouldn't when this function is called the first time
109     * in a new process. Ideally these flags shouldn't be part of the
110     * handle, but instead maintained in the kernel or at least
111     * out-of-line
112     */
113
114    // if this handle was created in this process, then we keep it as is.
115    private_handle_t* hnd = (private_handle_t*)handle;
116    if (hnd->pid != getpid()) {
117        hnd->base = 0;
118        hnd->lockState  = 0;
119        hnd->writeOwner = 0;
120    }
121    return 0;
122}
123
124int gralloc_unregister_buffer(gralloc_module_t const* module,
125        buffer_handle_t handle)
126{
127    if (private_handle_t::validate(handle) < 0)
128        return -EINVAL;
129
130    /*
131     * If the buffer has been mapped during a lock operation, it's time
132     * to un-map it. It's an error to be here with a locked buffer.
133     * NOTE: the framebuffer is handled differently and is never unmapped.
134     */
135
136    private_handle_t* hnd = (private_handle_t*)handle;
137
138    LOGE_IF(hnd->lockState & private_handle_t::LOCK_STATE_READ_MASK,
139            "handle %p still locked (state=%08x)",
140            hnd, hnd->lockState);
141
142    // never unmap buffers that were created in this process
143    if (hnd->pid != getpid()) {
144        if (hnd->lockState & private_handle_t::LOCK_STATE_MAPPED) {
145            gralloc_unmap(module, handle);
146        }
147        hnd->base = 0;
148        hnd->lockState  = 0;
149        hnd->writeOwner = 0;
150    }
151    return 0;
152}
153
154int terminateBuffer(gralloc_module_t const* module,
155        private_handle_t* hnd)
156{
157    /*
158     * If the buffer has been mapped during a lock operation, it's time
159     * to un-map it. It's an error to be here with a locked buffer.
160     */
161
162    LOGE_IF(hnd->lockState & private_handle_t::LOCK_STATE_READ_MASK,
163            "handle %p still locked (state=%08x)",
164            hnd, hnd->lockState);
165
166    if (hnd->lockState & private_handle_t::LOCK_STATE_MAPPED) {
167        // this buffer was mapped, unmap it now
168        if ((hnd->flags & private_handle_t::PRIV_FLAGS_USES_PMEM) &&
169            (hnd->pid == getpid())) {
170            // ... unless it's a "master" pmem buffer, that is a buffer
171            // mapped in the process it's been allocated.
172            // (see gralloc_alloc_buffer())
173        } else {
174            gralloc_unmap(module, hnd);
175        }
176    }
177
178    return 0;
179}
180
181int gralloc_lock(gralloc_module_t const* module,
182        buffer_handle_t handle, int usage,
183        int l, int t, int w, int h,
184        void** vaddr)
185{
186    if (private_handle_t::validate(handle) < 0)
187        return -EINVAL;
188
189    int err = 0;
190    private_handle_t* hnd = (private_handle_t*)handle;
191    int32_t current_value, new_value;
192    int retry;
193
194    do {
195        current_value = hnd->lockState;
196        new_value = current_value;
197
198        if (current_value & private_handle_t::LOCK_STATE_WRITE) {
199            // already locked for write
200            LOGE("handle %p already locked for write", handle);
201            return -EBUSY;
202        } else if (current_value & private_handle_t::LOCK_STATE_READ_MASK) {
203            // already locked for read
204            if (usage & (GRALLOC_USAGE_SW_WRITE_MASK | GRALLOC_USAGE_HW_RENDER)) {
205                LOGE("handle %p already locked for read", handle);
206                return -EBUSY;
207            } else {
208                // this is not an error
209                //LOGD("%p already locked for read... count = %d",
210                //        handle, (current_value & ~(1<<31)));
211            }
212        }
213
214        // not currently locked
215        if (usage & (GRALLOC_USAGE_SW_WRITE_MASK | GRALLOC_USAGE_HW_RENDER)) {
216            // locking for write
217            new_value |= private_handle_t::LOCK_STATE_WRITE;
218        }
219        new_value++;
220
221        retry = android_atomic_cmpxchg(current_value, new_value,
222                (volatile int32_t*)&hnd->lockState);
223    } while (retry);
224
225    if (new_value & private_handle_t::LOCK_STATE_WRITE) {
226        // locking for write, store the tid
227        hnd->writeOwner = gettid();
228    }
229
230    if (usage & (GRALLOC_USAGE_SW_READ_MASK | GRALLOC_USAGE_SW_WRITE_MASK)) {
231        if (!(current_value & private_handle_t::LOCK_STATE_MAPPED)) {
232            // we need to map for real
233            pthread_mutex_t* const lock = &sMapLock;
234            pthread_mutex_lock(lock);
235            if (!(hnd->lockState & private_handle_t::LOCK_STATE_MAPPED)) {
236                err = gralloc_map(module, handle, vaddr);
237                if (err == 0) {
238                    android_atomic_or(private_handle_t::LOCK_STATE_MAPPED,
239                            (volatile int32_t*)&(hnd->lockState));
240                }
241            }
242            pthread_mutex_unlock(lock);
243        }
244        *vaddr = (void*)hnd->base;
245    }
246
247    return err;
248}
249
250int gralloc_unlock(gralloc_module_t const* module,
251        buffer_handle_t handle)
252{
253    if (private_handle_t::validate(handle) < 0)
254        return -EINVAL;
255
256    private_handle_t* hnd = (private_handle_t*)handle;
257    int32_t current_value, new_value;
258
259    do {
260        current_value = hnd->lockState;
261        new_value = current_value;
262
263        if (current_value & private_handle_t::LOCK_STATE_WRITE) {
264            // locked for write
265            if (hnd->writeOwner == gettid()) {
266                hnd->writeOwner = 0;
267                new_value &= ~private_handle_t::LOCK_STATE_WRITE;
268            }
269        }
270
271        if ((new_value & private_handle_t::LOCK_STATE_READ_MASK) == 0) {
272            LOGE("handle %p not locked", handle);
273            return -EINVAL;
274        }
275
276        new_value--;
277
278    } while (android_atomic_cmpxchg(current_value, new_value,
279            (volatile int32_t*)&hnd->lockState));
280
281    return 0;
282}
283