| /* |
| * Copyright (C) 2016 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifdef LOG_TAG |
| #undef LOG_TAG |
| #endif |
| #define LOG_TAG "VSoCGrallocRegionRegistry" |
| // Ensure verbose messages appear even on release builds |
| #define LOG_NDEBUG 0 |
| |
| #include <limits.h> |
| #include <errno.h> |
| #include <pthread.h> |
| #include <unistd.h> |
| #include <string.h> |
| |
| #include <sys/mman.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| |
| #include <cutils/hashmap.h> |
| #include <log/log.h> |
| #include <cutils/atomic.h> |
| |
| #include <linux/ashmem.h> |
| |
| #include <hardware/hardware.h> |
| #include <hardware/gralloc.h> |
| #include <system/graphics.h> |
| |
| #include "gralloc_vsoc_priv.h" |
| |
| #include <deque> |
| #include <map> |
| #include <mutex> |
| |
| static const bool g_log_maps = false; |
| static const bool g_log_refs = false; |
| |
| struct GrallocRegion { |
| void* base_; |
| int num_references_; |
| |
| GrallocRegion() : base_(0), num_references_(0) { } |
| // Copy constructors are ok. |
| }; |
| |
| |
| static const char* get_buffer_name( |
| const private_handle_t* hnd, char output[ASHMEM_NAME_LEN]) { |
| output[0] = '\0'; |
| if (!hnd) { |
| ALOGE("Attempted to log gralloc name hnd=NULL"); |
| return output; |
| } |
| if (hnd->fd == -1) { |
| ALOGE("Attempted to log gralloc name hnd=%p with fd == -1", hnd); |
| return output; |
| } |
| int rval = ioctl(hnd->fd, ASHMEM_GET_NAME, output); |
| if (rval == -1) { |
| output[0] = '\0'; |
| } |
| return output; |
| } |
| |
| |
| static int str_hash(void* str) { |
| return hashmapHash(str, strlen(reinterpret_cast<const char*>(str))); |
| } |
| |
| |
| static bool str_equal(void* a, void* b) { |
| return strcmp( |
| reinterpret_cast<const char*>(a), |
| reinterpret_cast<const char*>(b)) == 0; |
| } |
| |
| |
| static Hashmap* get_regions() { |
| static Hashmap* regionMap = hashmapCreate(19, str_hash, str_equal); |
| return regionMap; |
| } |
| |
| |
| static GrallocRegion* lock_region_for_handle( |
| const private_handle_t* hnd, char region_name[ASHMEM_NAME_LEN]) { |
| region_name[0] = '\0'; |
| get_buffer_name(hnd, region_name); |
| Hashmap* hash = get_regions(); |
| hashmapLock(hash); |
| GrallocRegion* region = reinterpret_cast<GrallocRegion*>( |
| hashmapGet(hash, region_name)); |
| if (!region) { |
| region = new GrallocRegion; |
| hashmapPut(hash, strdup(region_name), region); |
| } |
| return region; |
| } |
| |
| |
| /* The current implementation uses only a single lock for all regions. |
| * This method takes a region to simplfy the refactoring if we go to |
| * finer-grained locks. |
| */ |
| static inline void unlock_region(GrallocRegion* ) { |
| hashmapUnlock(get_regions()); |
| } |
| |
| |
| /* |
| * surface_flinger can drop its last reference to a gralloc buffer (from the |
| * gralloc HAL's point of view) even though it also has work in flight to the |
| * GPU for that target. This causes segfaults in the swiftshader code. |
| * |
| * We create a compromise solution. On unmap we release the pages by mmaping |
| * anonymous memory over the range, but we don't release the address space. |
| * Instead we mark the address space for recycling into a new gralloc buffer. |
| * This means that the shaders can still write, that the writes won't land in |
| * the gralloc buffer, and the gralloc buffer memory can be released. |
| * |
| * When we're preparing to mmap a new gralloc buffer we see if we can recycle |
| * address space from a prior gralloc buffer. |
| * |
| * The protects the application layer from stray memory writes and pointer |
| * references to freed memory. It does mean that bad pixel data can land in |
| * a buffer in the case of a fast map-unmap-map sequence. However, that |
| * could also happen on a physical GPU. |
| * |
| * The alternative to this would be to create an elaborate reference counting |
| * mechanism below both gralloc and SwiftShader. However, we want to keep the |
| * SwiftShader code clean, so that seems undesirable. |
| * |
| * This problem also comes up for physical GPUs b/62267886. Background fo rthis |
| * solution is in b/118777601 |
| */ |
| |
| static std::map<size_t, std::deque<void*>> g_recycled_addrs; |
| std::mutex g_recycled_addrs_mutex; |
| |
| |
| |
| static void* recycle_mmap(void *addr, size_t length, int prot, int flags, |
| int fd, off_t offset) { |
| if (!addr) { |
| std::lock_guard<std::mutex> guard(g_recycled_addrs_mutex); |
| auto it = g_recycled_addrs.find(length); |
| if (it != g_recycled_addrs.end()) { |
| if (it->second.size()) { |
| addr = it->second.front(); |
| flags |= MAP_FIXED; |
| it->second.pop_front(); |
| } |
| } |
| } |
| return mmap(addr, length, prot, flags, fd, offset); |
| } |
| |
| |
| static int recycle_munmap(void *addr, size_t length) { |
| // Do this first so we don't hold the mutex during the syscall |
| if (addr != mmap(addr, length, PROT_READ|PROT_WRITE, |
| MAP_PRIVATE|MAP_ANONYMOUS|MAP_FIXED, -1, 0)) { |
| // Be conservative. Don't recycle here. |
| return -1; |
| } |
| std::lock_guard<std::mutex> guard(g_recycled_addrs_mutex); |
| g_recycled_addrs[length].push_back(addr); |
| return 0; |
| } |
| |
| |
| void* reference_region(const char* op, const private_handle_t* hnd) { |
| char name_buf[ASHMEM_NAME_LEN]; |
| GrallocRegion* region = lock_region_for_handle(hnd, name_buf); |
| if (!region->base_) { |
| void* mappedAddress = recycle_mmap( |
| 0, hnd->total_size, PROT_READ|PROT_WRITE, MAP_SHARED, hnd->fd, 0); |
| if (mappedAddress == MAP_FAILED) { |
| ALOGE("Could not mmap %s", strerror(errno)); |
| unlock_region(region); |
| return NULL; |
| } |
| // Set up the guard pages. The last page is always a guard |
| uintptr_t base = uintptr_t(mappedAddress); |
| uintptr_t addr = base + hnd->total_size - PAGE_SIZE; |
| if (mprotect((void*)addr, PAGE_SIZE, PROT_NONE) == -1) { |
| ALOGE("mprotect base=%p, pg=%p failed (%s)", (void*)base, (void*)addr, |
| strerror(errno)); |
| } |
| region->base_ = mappedAddress; |
| ALOGV_IF(g_log_maps, "Mapped %s hnd=%p fd=%d base=%p format=%s(0x%x) " |
| "width=%d height=%d stride_in_pixels=%d total_size=%d", |
| name_buf, hnd, hnd->fd, region->base_, |
| pixel_format_to_string(hnd->format), hnd->format, |
| hnd->x_res, hnd->y_res, hnd->stride_in_pixels, hnd->total_size); |
| } |
| |
| void* rval = region->base_; |
| ++region->num_references_; |
| ALOGV_IF(g_log_refs, "Referencing name=%s op=%s addr=%p new numRefs=%d", |
| name_buf, op, region->base_, region->num_references_); |
| unlock_region(region); |
| return rval; |
| } |
| |
| |
| int unreference_region(const char* op, const private_handle_t* hnd) { |
| char name_buf[ASHMEM_NAME_LEN]; |
| |
| GrallocRegion* region = lock_region_for_handle(hnd, name_buf); |
| if (!region->base_) { |
| ALOGE("Unmapping region with no map hnd=%p", hnd); |
| unlock_region(region); |
| return -1; |
| } |
| if (region->num_references_ < 1) { |
| ALOGE( |
| "unmap with hnd=%p, numReferences=%d", hnd, region->num_references_); |
| unlock_region(region); |
| return -1; |
| } |
| --region->num_references_; |
| if (!region->num_references_) { |
| ALOGV_IF(g_log_maps, "Unmapped %s hnd=%p fd=%d base=%p", name_buf, hnd, |
| hnd->fd, region->base_); |
| if (recycle_munmap(region->base_, hnd->total_size) < 0) { |
| ALOGE("Could not unmap %s", strerror(errno)); |
| } |
| region->base_ = 0; |
| } |
| ALOGV_IF(g_log_refs, "Unreferencing name=%s op=%s addr=%p new numRefs=%d", |
| name_buf, op, region->base_, region->num_references_); |
| unlock_region(region); |
| return 0; |
| } |