/**************************************************************************** * mm/tlsf/mm_tlsf.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you 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. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "tlsf/tlsf.h" #include "kasan/kasan.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #if UINTPTR_MAX <= UINT32_MAX # define MM_PTR_FMT_WIDTH 11 #elif UINTPTR_MAX <= UINT64_MAX # define MM_PTR_FMT_WIDTH 19 #endif /**************************************************************************** * Private Types ****************************************************************************/ struct mm_delaynode_s { FAR struct mm_delaynode_s *flink; }; struct mm_heap_s { /* Mutually exclusive access to this data set is enforced with * the following un-named mutex. */ mutex_t mm_lock; /* This is the size of the heap provided to mm */ size_t mm_heapsize; /* This is the first and last of the heap */ FAR void *mm_heapstart[CONFIG_MM_REGIONS]; FAR void *mm_heapend[CONFIG_MM_REGIONS]; #if CONFIG_MM_REGIONS > 1 int mm_nregions; #endif tlsf_t mm_tlsf; /* The tlfs context */ /* Free delay list, for some situation can't do free immdiately */ #ifdef CONFIG_SMP struct mm_delaynode_s *mm_delaylist[CONFIG_SMP_NCPUS]; #else struct mm_delaynode_s *mm_delaylist[1]; #endif #if defined(CONFIG_FS_PROCFS) && !defined(CONFIG_FS_PROCFS_EXCLUDE_MEMINFO) struct procfs_meminfo_entry_s mm_procfs; #endif }; struct memdump_info_s { pid_t pid; int blks; int size; }; #if CONFIG_MM_BACKTRACE >= 0 struct memdump_backtrace_s { pid_t pid; /* The pid for caller */ #if CONFIG_MM_BACKTRACE > 0 FAR void *backtrace[CONFIG_MM_BACKTRACE]; /* The backtrace buffer for caller */ #endif }; #endif /**************************************************************************** * Private Functions ****************************************************************************/ #if CONFIG_MM_BACKTRACE >= 0 /**************************************************************************** * Name: memdump_backtrace ****************************************************************************/ static void memdump_backtrace(FAR struct mm_heap_s *heap, FAR struct memdump_backtrace_s *dump) { dump->pid = getpid(); # if CONFIG_MM_BACKTRACE > 0 if (heap->mm_procfs.backtrace) { int ret = backtrace(dump->backtrace, CONFIG_MM_BACKTRACE); while (ret < CONFIG_MM_BACKTRACE) { dump->backtrace[ret++] = NULL; } } # endif } #endif /**************************************************************************** * Name: add_delaylist ****************************************************************************/ static void add_delaylist(FAR struct mm_heap_s *heap, FAR void *mem) { #if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__) FAR struct mm_delaynode_s *tmp = mem; irqstate_t flags; /* Delay the deallocation until a more appropriate time. */ flags = enter_critical_section(); tmp->flink = heap->mm_delaylist[up_cpu_index()]; heap->mm_delaylist[up_cpu_index()] = tmp; leave_critical_section(flags); #endif } /**************************************************************************** * Name: free_delaylist ****************************************************************************/ static void free_delaylist(FAR struct mm_heap_s *heap) { #if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__) FAR struct mm_delaynode_s *tmp; irqstate_t flags; /* Move the delay list to local */ flags = enter_critical_section(); tmp = heap->mm_delaylist[up_cpu_index()]; heap->mm_delaylist[up_cpu_index()] = NULL; leave_critical_section(flags); /* Test if the delayed is empty */ while (tmp) { FAR void *address; /* Get the first delayed deallocation */ address = tmp; tmp = tmp->flink; /* The address should always be non-NULL since that was checked in the * 'while' condition above. */ mm_free(heap, address); } #endif } /**************************************************************************** * Name: mallinfo_handler ****************************************************************************/ static void mallinfo_handler(FAR void *ptr, size_t size, int used, FAR void *user) { FAR struct mallinfo *info = user; if (!used) { info->ordblks++; info->fordblks += size; if (size > info->mxordblk) { info->mxordblk = size; } } else { info->aordblks++; } } #if CONFIG_MM_BACKTRACE >= 0 /**************************************************************************** * Name: mallinfo_task_handler ****************************************************************************/ static void mallinfo_task_handler(FAR void *ptr, size_t size, int used, FAR void *user) { FAR struct memdump_backtrace_s *dump; FAR struct mallinfo_task *info = user; size -= sizeof(struct memdump_backtrace_s); dump = ptr + size; if (used && dump->pid == info->pid) { info->aordblks++; info->uordblks += size; } } #endif /**************************************************************************** * Name: mm_lock * * Description: * Take the MM mutex. This may be called from the OS in certain conditions * when it is impossible to wait on a mutex: * 1.The idle process performs the memory corruption check. * 2.The task/thread free the memory in the exiting process. * * Input Parameters: * heap - heap instance want to take mutex * * Returned Value: * 0 if the lock can be taken, otherwise negative errno. * ****************************************************************************/ static int mm_lock(FAR struct mm_heap_s *heap) { #if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__) /* Check current environment */ if (up_interrupt_context()) { #if !defined(CONFIG_SMP) /* Check the mutex value, if held by someone, then return false. * Or, touch the heap internal data directly. */ return nxmutex_is_locked(&heap->mm_lock) ? -EAGAIN : 0; #else /* Can't take mutex in SMP interrupt handler */ return -EAGAIN; #endif } else #endif /* gettid() returns the task ID of the task at the head of the ready-to- * run task list. mm_lock() may be called during context * switches. There are certain situations during context switching when * the OS data structures are in flux and then can't be freed immediately * (e.g. the running thread stack). * * This is handled by gettid() to return the special value -ESRCH to * indicate this special situation. */ if (gettid() < 0) { return -ESRCH; } else { return nxmutex_lock(&heap->mm_lock); } } /**************************************************************************** * Name: mm_unlock * * Description: * Release the MM mutex when it is not longer needed. * ****************************************************************************/ static void mm_unlock(FAR struct mm_heap_s *heap) { #if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__) if (up_interrupt_context()) { return; } #endif DEBUGVERIFY(nxmutex_unlock(&heap->mm_lock)); } /**************************************************************************** * Name: memdump_handler ****************************************************************************/ static void memdump_handler(FAR void *ptr, size_t size, int used, FAR void *user) { FAR struct memdump_info_s *info = user; #if CONFIG_MM_BACKTRACE >= 0 FAR struct memdump_backtrace_s *dump; size -= sizeof(struct memdump_backtrace_s); dump = ptr + size; #endif if (used) { #if CONFIG_MM_BACKTRACE < 0 if (info->pid == -1) #else if (info->pid == -1 || dump->pid == info->pid) #endif { #if CONFIG_MM_BACKTRACE < 0 syslog(LOG_INFO, "%12zu%*p\n", size, MM_PTR_FMT_WIDTH, ptr); #else # if CONFIG_MM_BACKTRACE > 0 int i; FAR const char *format = " %0*p"; # endif char buf[CONFIG_MM_BACKTRACE * MM_PTR_FMT_WIDTH + 1]; buf[0] = '\0'; # if CONFIG_MM_BACKTRACE > 0 for (i = 0; i < CONFIG_MM_BACKTRACE && dump->backtrace[i]; i++) { sprintf(buf + i * MM_PTR_FMT_WIDTH, format, MM_PTR_FMT_WIDTH - 1, dump->backtrace[i]); } # endif syslog(LOG_INFO, "%6d%12zu%*p%s\n", (int)dump->pid, size, MM_PTR_FMT_WIDTH, ptr, buf); #endif info->blks++; info->size += size; } } else if (info->pid <= -2) { info->blks++; info->size += size; syslog(LOG_INFO, "%12zu%*p\n", size, MM_PTR_FMT_WIDTH, ptr); } } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: mm_addregion * * Description: * This function adds a region of contiguous memory to the selected heap. * * Input Parameters: * heap - The selected heap * heapstart - Start of the heap region * heapsize - Size of the heap region * * Returned Value: * None * * Assumptions: * ****************************************************************************/ void mm_addregion(FAR struct mm_heap_s *heap, FAR void *heapstart, size_t heapsize) { #if CONFIG_MM_REGIONS > 1 int idx; idx = heap->mm_nregions; /* Writing past CONFIG_MM_REGIONS would have catastrophic consequences */ DEBUGASSERT(idx < CONFIG_MM_REGIONS); if (idx >= CONFIG_MM_REGIONS) { return; } #else # define idx 0 #endif /* Register to KASan for access check */ kasan_register(heapstart, &heapsize); DEBUGVERIFY(mm_lock(heap)); minfo("Region %d: base=%p size=%zu\n", idx + 1, heapstart, heapsize); /* Add the size of this region to the total size of the heap */ heap->mm_heapsize += heapsize; /* Save the start and end of the heap */ heap->mm_heapstart[idx] = heapstart; heap->mm_heapend[idx] = heapstart + heapsize; #undef idx #if CONFIG_MM_REGIONS > 1 heap->mm_nregions++; #endif /* Add memory to the tlsf pool */ tlsf_add_pool(heap->mm_tlsf, heapstart, heapsize); mm_unlock(heap); } /**************************************************************************** * Name: mm_brkaddr * * Description: * Return the break address of a heap region. Zero is returned if the * memory region is not initialized. * ****************************************************************************/ FAR void *mm_brkaddr(FAR struct mm_heap_s *heap, int region) { #if CONFIG_MM_REGIONS > 1 DEBUGASSERT(region >= 0 && region < heap->mm_nregions); #else DEBUGASSERT(region == 0); #endif return heap->mm_heapend[region]; } /**************************************************************************** * Name: mm_calloc * * Descriptor: * mm_calloc() calculates the size of the allocation and calls mm_zalloc() * ****************************************************************************/ FAR void *mm_calloc(FAR struct mm_heap_s *heap, size_t n, size_t elem_size) { FAR void *ret = NULL; /* Verify input parameters */ if (n > 0 && elem_size > 0) { /* Assure that the following multiplication cannot overflow the size_t * type, i.e., that: SIZE_MAX >= n * elem_size * * Refer to SEI CERT C Coding Standard. */ if (n <= (SIZE_MAX / elem_size)) { ret = mm_zalloc(heap, n * elem_size); } } return ret; } #ifdef CONFIG_DEBUG_MM /**************************************************************************** * Name: mm_checkcorruption * * Description: * mm_checkcorruption is used to check whether memory heap is normal. * ****************************************************************************/ void mm_checkcorruption(FAR struct mm_heap_s *heap) { #if CONFIG_MM_REGIONS > 1 int region; #else # define region 0 #endif /* Visit each region */ #if CONFIG_MM_REGIONS > 1 for (region = 0; region < heap->mm_nregions; region++) #endif { /* Retake the mutex for each region to reduce latencies */ if (mm_lock(heap) < 0) { return; } /* Check tlsf control block in the first pass */ if (region == 0) { tlsf_check(heap->mm_tlsf); } /* Check tlsf pool in each iteration temporarily */ tlsf_check_pool(heap->mm_heapstart[region]); /* Release the mutex */ mm_unlock(heap); } #undef region } #endif /**************************************************************************** * Name: mm_extend * * Description: * Extend a heap region by add a block of (virtually) contiguous memory * to the end of the heap. * ****************************************************************************/ void mm_extend(FAR struct mm_heap_s *heap, FAR void *mem, size_t size, int region) { size_t oldsize; /* Make sure that we were passed valid parameters */ #if CONFIG_MM_REGIONS > 1 DEBUGASSERT(region >= 0 && region < heap->mm_nregions); #else DEBUGASSERT(region == 0); #endif DEBUGASSERT(mem == heap->mm_heapend[region]); /* Take the memory manager mutex */ DEBUGVERIFY(mm_lock(heap)); /* Extend the tlsf pool */ oldsize = heap->mm_heapend[region] - heap->mm_heapstart[region]; tlsf_extend_pool(heap->mm_tlsf, heap->mm_heapstart[region], oldsize, size); /* Save the new size */ heap->mm_heapsize += size; heap->mm_heapend[region] += size; mm_unlock(heap); } /**************************************************************************** * Name: mm_free * * Description: * Returns a chunk of memory to the list of free nodes, merging with * adjacent free chunks if possible. * ****************************************************************************/ void mm_free(FAR struct mm_heap_s *heap, FAR void *mem) { int ret; UNUSED(ret); minfo("Freeing %p\n", mem); /* Protect against attempts to free a NULL reference */ if (!mem) { return; } if (mm_lock(heap) == 0) { kasan_poison(mem, mm_malloc_size(mem)); /* Pass, return to the tlsf pool */ tlsf_free(heap->mm_tlsf, mem); mm_unlock(heap); } else { /* Add to the delay list(see the comment in mm_lock) */ add_delaylist(heap, mem); } } /**************************************************************************** * Name: mm_heapmember * * Description: * Check if an address lies in the heap. * * Parameters: * heap - The heap to check * mem - The address to check * * Return Value: * true if the address is a member of the heap. false if not * not. If the address is not a member of the heap, then it * must be a member of the user-space heap (unchecked) * ****************************************************************************/ bool mm_heapmember(FAR struct mm_heap_s *heap, FAR void *mem) { #if CONFIG_MM_REGIONS > 1 int i; /* A valid address from the heap for this region would have to lie * between the region's two guard nodes. */ for (i = 0; i < heap->mm_nregions; i++) { if (mem >= heap->mm_heapstart[i] && mem < heap->mm_heapend[i]) { return true; } } /* The address does not like any any region assigned to the heap */ return false; #else /* A valid address from the heap would have to lie between the * two guard nodes. */ if (mem >= heap->mm_heapstart[0] && mem < heap->mm_heapend[0]) { return true; } /* Otherwise, the address does not lie in the heap */ return false; #endif } /**************************************************************************** * Name: mm_initialize * * Description: * Initialize the selected heap data structures, providing the initial * heap region. * * Input Parameters: * heap - The selected heap * heapstart - Start of the initial heap region * heapsize - Size of the initial heap region * * Returned Value: * None * * Assumptions: * ****************************************************************************/ FAR struct mm_heap_s *mm_initialize(FAR const char *name, FAR void *heapstart, size_t heapsize) { FAR struct mm_heap_s *heap; minfo("Heap: name=%s start=%p size=%zu\n", name, heapstart, heapsize); /* Reserve a block space for mm_heap_s context */ DEBUGASSERT(heapsize > sizeof(struct mm_heap_s)); heap = (FAR struct mm_heap_s *)heapstart; memset(heap, 0, sizeof(struct mm_heap_s)); heapstart += sizeof(struct mm_heap_s); heapsize -= sizeof(struct mm_heap_s); /* Allocate and create TLSF context */ DEBUGASSERT(heapsize > tlsf_size()); heap->mm_tlsf = tlsf_create(heapstart); heapstart += tlsf_size(); heapsize -= tlsf_size(); /* Initialize the malloc mutex (to support one-at- * a-time access to private data sets). */ nxmutex_init(&heap->mm_lock); /* Add the initial region of memory to the heap */ mm_addregion(heap, heapstart, heapsize); #if defined(CONFIG_FS_PROCFS) && !defined(CONFIG_FS_PROCFS_EXCLUDE_MEMINFO) #if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__) heap->mm_procfs.name = name; heap->mm_procfs.heap = heap; # ifdef CONFIG_MM_BACKTRACE_DEFAULT heap->mm_procfs.backtrace = true; # endif procfs_register_meminfo(&heap->mm_procfs); #endif #endif return heap; } /**************************************************************************** * Name: mm_mallinfo * * Description: * mallinfo returns a copy of updated current heap information. * ****************************************************************************/ int mm_mallinfo(FAR struct mm_heap_s *heap, FAR struct mallinfo *info) { #if CONFIG_MM_REGIONS > 1 int region; #else # define region 0 #endif DEBUGASSERT(info); memset(info, 0, sizeof(struct mallinfo)); /* Visit each region */ #if CONFIG_MM_REGIONS > 1 for (region = 0; region < heap->mm_nregions; region++) #endif { /* Retake the mutex for each region to reduce latencies */ DEBUGVERIFY(mm_lock(heap)); tlsf_walk_pool(heap->mm_heapstart[region], mallinfo_handler, info); mm_unlock(heap); } #undef region info->arena = heap->mm_heapsize; info->uordblks = info->arena - info->fordblks; return OK; } #if CONFIG_MM_BACKTRACE >= 0 int mm_mallinfo_task(FAR struct mm_heap_s *heap, FAR struct mallinfo_task *info) { #if CONFIG_MM_REGIONS > 1 int region; #else #define region 0 #endif DEBUGASSERT(info); info->uordblks = 0; info->aordblks = 0; #if CONFIG_MM_REGIONS > 1 for (region = 0; region < heap->mm_nregions; region++) #endif { /* Retake the mutex for each region to reduce latencies */ DEBUGVERIFY(mm_lock(heap)); tlsf_walk_pool(heap->mm_heapstart[region], mallinfo_task_handler, info); mm_unlock(heap); } #undef region return OK; } #endif /**************************************************************************** * Name: mm_memdump * * Description: * mm_memdump returns a memory info about specified pid of task/thread. * if pid equals -1, this function will dump all allocated node and output * backtrace for every allocated node for this heap, if pid equals -2, this * function will dump all free node for this heap, and if pid is greater * than or equal to 0, will dump pid allocated node and output backtrace. ****************************************************************************/ void mm_memdump(FAR struct mm_heap_s *heap, pid_t pid) { #if CONFIG_MM_REGIONS > 1 int region; #else # define region 0 #endif struct memdump_info_s info; if (pid >= -1) { syslog(LOG_INFO, "Dump all used memory node info:\n"); #if CONFIG_MM_BACKTRACE < 0 syslog(LOG_INFO, "%12s%*s\n", "Size", MM_PTR_FMT_WIDTH, "Address"); #else syslog(LOG_INFO, "%6s%12s%*s %s\n", "PID", "Size", MM_PTR_FMT_WIDTH, "Address", "Backtrace"); #endif } else { syslog(LOG_INFO, "Dump all free memory node info:\n"); syslog(LOG_INFO, "%12s%*s\n", "Size", MM_PTR_FMT_WIDTH, "Address"); } info.blks = 0; info.size = 0; info.pid = pid; #if CONFIG_MM_REGIONS > 1 for (region = 0; region < heap->mm_nregions; region++) #endif { DEBUGVERIFY(mm_lock(heap)); tlsf_walk_pool(heap->mm_heapstart[region], memdump_handler, &info); mm_unlock(heap); } #undef region syslog(LOG_INFO, "%12s%12s\n", "Total Blks", "Total Size"); syslog(LOG_INFO, "%12d%12d\n", info.blks, info.size); } /**************************************************************************** * Name: mm_malloc_size ****************************************************************************/ size_t mm_malloc_size(FAR void *mem) { #if CONFIG_MM_BACKTRACE >= 0 return tlsf_block_size(mem) - sizeof(struct memdump_backtrace_s); #else return tlsf_block_size(mem); #endif } /**************************************************************************** * Name: mm_malloc * * Description: * Find the smallest chunk that satisfies the request. Take the memory from * that chunk, save the remaining, smaller chunk (if any). * * 8-byte alignment of the allocated data is assured. * ****************************************************************************/ FAR void *mm_malloc(FAR struct mm_heap_s *heap, size_t size) { FAR void *ret; /* Free the delay list first */ free_delaylist(heap); /* Allocate from the tlsf pool */ DEBUGVERIFY(mm_lock(heap)); #if CONFIG_MM_BACKTRACE >= 0 ret = tlsf_malloc(heap->mm_tlsf, size + sizeof(struct memdump_backtrace_s)); #else ret = tlsf_malloc(heap->mm_tlsf, size); #endif mm_unlock(heap); if (ret) { #if CONFIG_MM_BACKTRACE >= 0 FAR struct memdump_backtrace_s *dump = ret + mm_malloc_size(ret); memdump_backtrace(heap, dump); #endif kasan_unpoison(ret, mm_malloc_size(ret)); } return ret; } /**************************************************************************** * Name: mm_memalign * * Description: * memalign requests more than enough space from malloc, finds a region * within that chunk that meets the alignment request and then frees any * leading or trailing space. * * The alignment argument must be a power of two (not checked). 8-byte * alignment is guaranteed by normal malloc calls. * ****************************************************************************/ FAR void *mm_memalign(FAR struct mm_heap_s *heap, size_t alignment, size_t size) { FAR void *ret; /* Free the delay list first */ free_delaylist(heap); /* Allocate from the tlsf pool */ DEBUGVERIFY(mm_lock(heap)); #if CONFIG_MM_BACKTRACE >= 0 ret = tlsf_memalign(heap->mm_tlsf, alignment, size + sizeof(struct memdump_backtrace_s)); #else ret = tlsf_memalign(heap->mm_tlsf, alignment, size); #endif mm_unlock(heap); if (ret) { #if CONFIG_MM_BACKTRACE >= 0 FAR struct memdump_backtrace_s *dump = ret + mm_malloc_size(ret); memdump_backtrace(heap, dump); #endif kasan_unpoison(ret, mm_malloc_size(ret)); } return ret; } /**************************************************************************** * Name: mm_realloc * * Description: * If the reallocation is for less space, then: * * (1) the current allocation is reduced in size * (2) the remainder at the end of the allocation is returned to the * free list. * * If the request is for more space and the current allocation can be * extended, it will be extended by: * * (1) Taking the additional space from the following free chunk, or * (2) Taking the additional space from the preceding free chunk. * (3) Or both * * If the request is for more space but the current chunk cannot be * extended, then malloc a new buffer, copy the data into the new buffer, * and free the old buffer. * ****************************************************************************/ FAR void *mm_realloc(FAR struct mm_heap_s *heap, FAR void *oldmem, size_t size) { FAR void *newmem; #ifdef CONFIG_MM_KASAN if (oldmem == NULL) { return mm_malloc(heap, size); } if (size == 0) { mm_free(heap, oldmem); return NULL; } newmem = mm_malloc(heap, size); if (newmem) { if (size > mm_malloc_size(oldmem)) { size = mm_malloc_size(oldmem); } memcpy(newmem, oldmem, size); mm_free(heap, oldmem); } #else /* Free the delay list first */ free_delaylist(heap); /* Allocate from the tlsf pool */ DEBUGVERIFY(mm_lock(heap)); #if CONFIG_MM_BACKTRACE >= 0 newmem = tlsf_realloc(heap->mm_tlsf, oldmem, size + sizeof(struct memdump_backtrace_s)); #else newmem = tlsf_realloc(heap->mm_tlsf, oldmem, size); #endif mm_unlock(heap); #if CONFIG_MM_BACKTRACE >= 0 if (newmem) { FAR struct memdump_backtrace_s *dump = newmem + mm_malloc_size(newmem); memdump_backtrace(heap, dump); } #endif #endif return newmem; } /**************************************************************************** * Name: mm_uninitialize * * Description: * Uninitialize the selected heap data structures. * * Input Parameters: * heap - The heap to uninitialize * * Returned Value: * None * ****************************************************************************/ void mm_uninitialize(FAR struct mm_heap_s *heap) { #if defined(CONFIG_FS_PROCFS) && !defined(CONFIG_FS_PROCFS_EXCLUDE_MEMINFO) # if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__) procfs_unregister_meminfo(&heap->mm_procfs); # endif #endif nxmutex_destroy(&heap->mm_lock); tlsf_destroy(&heap->mm_tlsf); } /**************************************************************************** * Name: mm_zalloc * * Description: * mm_zalloc calls mm_malloc, then zeroes out the allocated chunk. * ****************************************************************************/ FAR void *mm_zalloc(FAR struct mm_heap_s *heap, size_t size) { FAR void *alloc = mm_malloc(heap, size); if (alloc) { memset(alloc, 0, size); } return alloc; }