jlaitine commented on code in PR #8026: URL: https://github.com/apache/nuttx/pull/8026#discussion_r1063431469
########## mm/map/mm_map.c: ########## @@ -0,0 +1,325 @@ +/**************************************************************************** + * mm/map/mm_map.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 <nuttx/mm/map.h> +#include <stdbool.h> +#include <stddef.h> +#include <nuttx/sched.h> +#include <nuttx/kmalloc.h> +#include <assert.h> + +#if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__) + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +static bool in_range(FAR const void *start, size_t length, + FAR const void *range_start, size_t range_length) +{ + char *u_start = (char *)start; + char *u_end = u_start + length; + char *r_start = (char *)range_start; + char *r_end = r_start + range_length; + + return (u_start >= r_start && u_start < r_end && /* start is in range */ + u_end >= r_start && u_end <= r_end); /* end is in range */ +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: mm_map_lock + * + * Description: + * Get exclusive access to task_group's mm_map + * + ****************************************************************************/ + +int mm_map_lock(FAR struct task_group_s *group) +{ + return nxrmutex_lock(&group->tg_mm_map.mm_map_mutex); +} + +/**************************************************************************** + * Name: mm_map_unlock + * + * Description: + * Relinquish exclusive access to task_group's mm_map + * + ****************************************************************************/ + +void mm_map_unlock(FAR struct task_group_s *group) +{ + DEBUGVERIFY(nxrmutex_unlock(&group->tg_mm_map.mm_map_mutex)); +} + +/**************************************************************************** + * Name: mm_map_initialize + * + * Description: + * Allocates a task group specific mm_map stucture. Called when the group + * is initialized + * + ****************************************************************************/ + +void mm_map_initialize(FAR struct mm_map_s *mm) +{ + sq_init(&mm->mm_map_sq); + nxrmutex_init(&mm->mm_map_mutex); +} + +/**************************************************************************** + * Name: mm_map_destroy + * + * Description: + * De-allocates a task group specific mm_map stucture and the mm_map_mutex + * + ****************************************************************************/ + +void mm_map_destroy(FAR struct mm_map_s *mm) +{ + FAR struct mm_map_entry_s *map; + + while ((map = (FAR struct mm_map_entry_s *)sq_remfirst(&mm->mm_map_sq))) + { + /* Pass null as group argument to indicate that actual MMU mappings + * must not be touched. The process is being deleted and we don't + * know in which context we are. Only kernel memory allocations + * need to be freed by drivers + */ + + /* Unmap the whole region */ + + if (!map->munmap || + map->munmap(NULL, map, map->vaddr, map->length) < 0) + { + /* The driver doesn't support unmap, or unmap failed. Just free + * the entry. + * A call to drivers munmap failing here would be a bug in the + * driver. The driver should be able to unmap at least the full + * area, which it has mapped + */ + + kmm_free(map); + } + } + + nxrmutex_destroy(&mm->mm_map_mutex); +} + +/**************************************************************************** + * Name: mm_map_add + * + * Description: + * Add a mapping to task group's mm_map list + * + ****************************************************************************/ + +int mm_map_add(FAR struct mm_map_entry_s *entry) +{ + FAR struct tcb_s *tcb = nxsched_self(); + FAR struct task_group_s *group = tcb->group; + FAR struct mm_map_s *mm = &group->tg_mm_map; + FAR struct mm_map_entry_s *map; + int ret; + + if (!entry) + { + return -EINVAL; + } + + /* Copy the provided mapping and add to the list */ + + map = kmm_malloc(sizeof(struct mm_map_entry_s)); + if (!map) + { + return -EINVAL; + } + + *map = *entry; + + ret = mm_map_lock(group); + if (ret < 0) + { + kmm_free(map); + return ret; + } + + sq_addfirst((sq_entry_t *)map, &mm->mm_map_sq); + + mm_map_unlock(group); + + return OK; +} + +/**************************************************************************** + * Name: mm_map_next + * + * Description: + * Returns the next mapping in the list. + * + ****************************************************************************/ + +FAR struct mm_map_entry_s *mm_map_next( + FAR const struct mm_map_entry_s *entry) +{ + FAR struct tcb_s *tcb = nxsched_self(); + FAR struct task_group_s *group = tcb->group; + FAR struct mm_map_s *mm = &group->tg_mm_map; + FAR struct mm_map_entry_s *map = NULL; + + if (mm_map_lock(group) == OK) + { + if (entry == NULL) + { + map = (struct mm_map_entry_s *)sq_peek(&mm->mm_map_sq); + } + else + { + map = (struct mm_map_entry_s *)sq_next(((sq_entry_t *)entry)); + } + + mm_map_unlock(group); + } + + return map; +} + +/**************************************************************************** + * Name: mm_map_find + * + * Description: + * Find the first mapping containing the range from the task group's list + * + ****************************************************************************/ + +FAR struct mm_map_entry_s *mm_map_find(FAR const void *vaddr, size_t length) +{ + FAR struct tcb_s *tcb = nxsched_self(); + FAR struct task_group_s *group = tcb->group; + FAR struct mm_map_s *mm = &group->tg_mm_map; + FAR struct mm_map_entry_s *map = NULL; + + if (mm_map_lock(group) == OK) + { + map = (struct mm_map_entry_s *)sq_peek(&mm->mm_map_sq); + + while (map && !in_range(vaddr, length, map->vaddr, map->length)) + { + map = (struct mm_map_entry_s *)sq_next(((sq_entry_t *)map)); + } + + mm_map_unlock(group); + } + + return map; +} + +/**************************************************************************** + * Name: mm_map_remove + * + * Description: + * Remove a mapping from the task group's list + * + ****************************************************************************/ + +int mm_map_remove(FAR struct task_group_s *group, + FAR struct mm_map_entry_s **map) +{ + FAR struct mm_map_entry_s *prev; + FAR struct mm_map_entry_s *r = NULL; + FAR struct mm_map_s *mm; + + if (!group) + { + /* We end up in here only through mm_map_destroy. The address + * environment is being destroyed and the group is not valid. + * just delete the entry + */ + + goto free_mem; + } + + mm = &group->tg_mm_map; + + int ret = mm_map_lock(group); + if (ret < 0) + { + return ret; + } + + prev = (struct mm_map_entry_s *)sq_peek(&mm->mm_map_sq); + + /* Check if the list was empty */ + + if (!prev) + { + mm_map_unlock(group); + return -ENOENT; + } + + /* Check if removing the first item */ + + if (*map == prev) + { + sq_remfirst(&mm->mm_map_sq); + *map = NULL; + r = prev; + } + else + { + /* Loop through the remaining items to find the one to be removed */ + + while ((r = (struct mm_map_entry_s *)sq_next(((sq_entry_t *)prev)))) + { + if (*map == r) + { + sq_remafter((sq_entry_t *)prev, &mm->mm_map_sq); + *map = prev; Review Comment: And yes, you are absolutely right. These two shouldn't be mixed. I want to stick to 2., but have an exception for mm_map_remove for the practical reason that process exit case cannot be handled without some extra argument indicating that the context is not valid But this argument doesn't need to be "group", it could as well be a boolean flag "on_process_exit" or such, if you prefer -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: commits-unsubscr...@nuttx.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
