| /* mm/ashmem.c |
| ** |
| ** Anonymous Shared Memory Subsystem, ashmem |
| ** |
| ** Copyright (C) 2008 Google, Inc. |
| ** |
| ** Robert Love <rlove@google.com> |
| ** |
| ** This software is licensed under the terms of the GNU General Public |
| ** License version 2, as published by the Free Software Foundation, and |
| ** may be copied, distributed, and modified under those terms. |
| ** |
| ** This program is distributed in the hope that it will be useful, |
| ** but WITHOUT ANY WARRANTY; without even the implied warranty of |
| ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| ** GNU General Public License for more details. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/file.h> |
| #include <linux/fs.h> |
| #include <linux/miscdevice.h> |
| #include <linux/security.h> |
| #include <linux/mm.h> |
| #include <linux/mman.h> |
| #include <linux/uaccess.h> |
| #include <linux/personality.h> |
| #include <linux/bitops.h> |
| #include <linux/mutex.h> |
| #include <linux/shmem_fs.h> |
| #include <linux/ashmem.h> |
| #include <asm/cacheflush.h> |
| |
| #define ASHMEM_NAME_PREFIX "dev/ashmem/" |
| #define ASHMEM_NAME_PREFIX_LEN (sizeof(ASHMEM_NAME_PREFIX) - 1) |
| #define ASHMEM_FULL_NAME_LEN (ASHMEM_NAME_LEN + ASHMEM_NAME_PREFIX_LEN) |
| |
| /* |
| * ashmem_area - anonymous shared memory area |
| * Lifecycle: From our parent file's open() until its release() |
| * Locking: Protected by `ashmem_mutex' |
| * Big Note: Mappings do NOT pin this structure; it dies on close() |
| */ |
| struct ashmem_area { |
| char name[ASHMEM_FULL_NAME_LEN]; /* optional name in /proc/pid/maps */ |
| struct list_head unpinned_list; /* list of all ashmem areas */ |
| struct file *file; /* the shmem-based backing file */ |
| size_t size; /* size of the mapping, in bytes */ |
| unsigned long vm_start; /* Start address of vm_area |
| * which maps this ashmem */ |
| unsigned long prot_mask; /* allowed prot bits, as vm_flags */ |
| }; |
| |
| /* |
| * ashmem_range - represents an interval of unpinned (evictable) pages |
| * Lifecycle: From unpin to pin |
| * Locking: Protected by `ashmem_mutex' |
| */ |
| struct ashmem_range { |
| struct list_head lru; /* entry in LRU list */ |
| struct list_head unpinned; /* entry in its area's unpinned list */ |
| struct ashmem_area *asma; /* associated area */ |
| size_t pgstart; /* starting page, inclusive */ |
| size_t pgend; /* ending page, inclusive */ |
| unsigned int purged; /* ASHMEM_NOT or ASHMEM_WAS_PURGED */ |
| }; |
| |
| /* LRU list of unpinned pages, protected by ashmem_mutex */ |
| static LIST_HEAD(ashmem_lru_list); |
| |
| /* Count of pages on our LRU list, protected by ashmem_mutex */ |
| static unsigned long lru_count; |
| |
| /* |
| * ashmem_mutex - protects the list of and each individual ashmem_area |
| * |
| * Lock Ordering: ashmex_mutex -> i_mutex -> i_alloc_sem |
| */ |
| static DEFINE_MUTEX(ashmem_mutex); |
| |
| static struct kmem_cache *ashmem_area_cachep __read_mostly; |
| static struct kmem_cache *ashmem_range_cachep __read_mostly; |
| |
| #define range_size(range) \ |
| ((range)->pgend - (range)->pgstart + 1) |
| |
| #define range_on_lru(range) \ |
| ((range)->purged == ASHMEM_NOT_PURGED) |
| |
| #define page_range_subsumes_range(range, start, end) \ |
| (((range)->pgstart >= (start)) && ((range)->pgend <= (end))) |
| |
| #define page_range_subsumed_by_range(range, start, end) \ |
| (((range)->pgstart <= (start)) && ((range)->pgend >= (end))) |
| |
| #define page_in_range(range, page) \ |
| (((range)->pgstart <= (page)) && ((range)->pgend >= (page))) |
| |
| #define page_range_in_range(range, start, end) \ |
| (page_in_range(range, start) || page_in_range(range, end) || \ |
| page_range_subsumes_range(range, start, end)) |
| |
| #define range_before_page(range, page) \ |
| ((range)->pgend < (page)) |
| |
| #define PROT_MASK (PROT_EXEC | PROT_READ | PROT_WRITE) |
| |
| static inline void lru_add(struct ashmem_range *range) |
| { |
| list_add_tail(&range->lru, &ashmem_lru_list); |
| lru_count += range_size(range); |
| } |
| |
| static inline void lru_del(struct ashmem_range *range) |
| { |
| list_del(&range->lru); |
| lru_count -= range_size(range); |
| } |
| |
| /* |
| * range_alloc - allocate and initialize a new ashmem_range structure |
| * |
| * 'asma' - associated ashmem_area |
| * 'prev_range' - the previous ashmem_range in the sorted asma->unpinned list |
| * 'purged' - initial purge value (ASMEM_NOT_PURGED or ASHMEM_WAS_PURGED) |
| * 'start' - starting page, inclusive |
| * 'end' - ending page, inclusive |
| * |
| * Caller must hold ashmem_mutex. |
| */ |
| static int range_alloc(struct ashmem_area *asma, |
| struct ashmem_range *prev_range, unsigned int purged, |
| size_t start, size_t end) |
| { |
| struct ashmem_range *range; |
| |
| range = kmem_cache_zalloc(ashmem_range_cachep, GFP_KERNEL); |
| if (unlikely(!range)) |
| return -ENOMEM; |
| |
| range->asma = asma; |
| range->pgstart = start; |
| range->pgend = end; |
| range->purged = purged; |
| |
| list_add_tail(&range->unpinned, &prev_range->unpinned); |
| |
| if (range_on_lru(range)) |
| lru_add(range); |
| |
| return 0; |
| } |
| |
| static void range_del(struct ashmem_range *range) |
| { |
| list_del(&range->unpinned); |
| if (range_on_lru(range)) |
| lru_del(range); |
| kmem_cache_free(ashmem_range_cachep, range); |
| } |
| |
| /* |
| * range_shrink - shrinks a range |
| * |
| * Caller must hold ashmem_mutex. |
| */ |
| static inline void range_shrink(struct ashmem_range *range, |
| size_t start, size_t end) |
| { |
| size_t pre = range_size(range); |
| |
| range->pgstart = start; |
| range->pgend = end; |
| |
| if (range_on_lru(range)) |
| lru_count -= pre - range_size(range); |
| } |
| |
| static int ashmem_open(struct inode *inode, struct file *file) |
| { |
| struct ashmem_area *asma; |
| int ret; |
| |
| ret = generic_file_open(inode, file); |
| if (unlikely(ret)) |
| return ret; |
| |
| asma = kmem_cache_zalloc(ashmem_area_cachep, GFP_KERNEL); |
| if (unlikely(!asma)) |
| return -ENOMEM; |
| |
| INIT_LIST_HEAD(&asma->unpinned_list); |
| memcpy(asma->name, ASHMEM_NAME_PREFIX, ASHMEM_NAME_PREFIX_LEN); |
| asma->prot_mask = PROT_MASK; |
| file->private_data = asma; |
| |
| return 0; |
| } |
| |
| static int ashmem_release(struct inode *ignored, struct file *file) |
| { |
| struct ashmem_area *asma = file->private_data; |
| struct ashmem_range *range, *next; |
| |
| mutex_lock(&ashmem_mutex); |
| list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) |
| range_del(range); |
| mutex_unlock(&ashmem_mutex); |
| |
| if (asma->file) |
| fput(asma->file); |
| kmem_cache_free(ashmem_area_cachep, asma); |
| |
| return 0; |
| } |
| |
| static ssize_t ashmem_read(struct file *file, char __user *buf, |
| size_t len, loff_t *pos) |
| { |
| struct ashmem_area *asma = file->private_data; |
| int ret = 0; |
| |
| mutex_lock(&ashmem_mutex); |
| |
| /* If size is not set, or set to 0, always return EOF. */ |
| if (asma->size == 0) |
| goto out; |
| |
| if (!asma->file) { |
| ret = -EBADF; |
| goto out; |
| } |
| |
| ret = asma->file->f_op->read(asma->file, buf, len, pos); |
| if (ret < 0) |
| goto out; |
| |
| /** Update backing file pos, since f_ops->read() doesn't */ |
| asma->file->f_pos = *pos; |
| |
| out: |
| mutex_unlock(&ashmem_mutex); |
| return ret; |
| } |
| |
| static loff_t ashmem_llseek(struct file *file, loff_t offset, int origin) |
| { |
| struct ashmem_area *asma = file->private_data; |
| int ret; |
| |
| mutex_lock(&ashmem_mutex); |
| |
| if (asma->size == 0) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (!asma->file) { |
| ret = -EBADF; |
| goto out; |
| } |
| |
| ret = asma->file->f_op->llseek(asma->file, offset, origin); |
| if (ret < 0) |
| goto out; |
| |
| /** Copy f_pos from backing file, since f_ops->llseek() sets it */ |
| file->f_pos = asma->file->f_pos; |
| |
| out: |
| mutex_unlock(&ashmem_mutex); |
| return ret; |
| } |
| |
| static inline unsigned long calc_vm_may_flags(unsigned long prot) |
| { |
| return _calc_vm_trans(prot, PROT_READ, VM_MAYREAD) | |
| _calc_vm_trans(prot, PROT_WRITE, VM_MAYWRITE) | |
| _calc_vm_trans(prot, PROT_EXEC, VM_MAYEXEC); |
| } |
| |
| static int ashmem_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| struct ashmem_area *asma = file->private_data; |
| int ret = 0; |
| |
| mutex_lock(&ashmem_mutex); |
| |
| /* user needs to SET_SIZE before mapping */ |
| if (unlikely(!asma->size)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| /* requested protection bits must match our allowed protection mask */ |
| if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask)) & |
| calc_vm_prot_bits(PROT_MASK))) { |
| ret = -EPERM; |
| goto out; |
| } |
| vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask); |
| |
| if (!asma->file) { |
| char *name = ASHMEM_NAME_DEF; |
| struct file *vmfile; |
| |
| if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') |
| name = asma->name; |
| |
| /* ... and allocate the backing shmem file */ |
| vmfile = shmem_file_setup(name, asma->size, vma->vm_flags); |
| if (unlikely(IS_ERR(vmfile))) { |
| ret = PTR_ERR(vmfile); |
| goto out; |
| } |
| asma->file = vmfile; |
| } |
| get_file(asma->file); |
| |
| if (vma->vm_flags & VM_SHARED) |
| shmem_set_file(vma, asma->file); |
| else { |
| if (vma->vm_file) |
| fput(vma->vm_file); |
| vma->vm_file = asma->file; |
| } |
| vma->vm_flags |= VM_CAN_NONLINEAR; |
| asma->vm_start = vma->vm_start; |
| |
| out: |
| mutex_unlock(&ashmem_mutex); |
| return ret; |
| } |
| |
| /* |
| * ashmem_shrink - our cache shrinker, called from mm/vmscan.c :: shrink_slab |
| * |
| * 'nr_to_scan' is the number of objects (pages) to prune, or 0 to query how |
| * many objects (pages) we have in total. |
| * |
| * 'gfp_mask' is the mask of the allocation that got us into this mess. |
| * |
| * Return value is the number of objects (pages) remaining, or -1 if we cannot |
| * proceed without risk of deadlock (due to gfp_mask). |
| * |
| * We approximate LRU via least-recently-unpinned, jettisoning unpinned partial |
| * chunks of ashmem regions LRU-wise one-at-a-time until we hit 'nr_to_scan' |
| * pages freed. |
| */ |
| static int ashmem_shrink(struct shrinker *s, struct shrink_control *sc) |
| { |
| struct ashmem_range *range, *next; |
| |
| /* We might recurse into filesystem code, so bail out if necessary */ |
| if (sc->nr_to_scan && !(sc->gfp_mask & __GFP_FS)) |
| return -1; |
| if (!sc->nr_to_scan) |
| return lru_count; |
| |
| mutex_lock(&ashmem_mutex); |
| list_for_each_entry_safe(range, next, &ashmem_lru_list, lru) { |
| struct inode *inode = range->asma->file->f_dentry->d_inode; |
| loff_t start = range->pgstart * PAGE_SIZE; |
| loff_t end = (range->pgend + 1) * PAGE_SIZE - 1; |
| |
| vmtruncate_range(inode, start, end); |
| range->purged = ASHMEM_WAS_PURGED; |
| lru_del(range); |
| |
| sc->nr_to_scan -= range_size(range); |
| if (sc->nr_to_scan <= 0) |
| break; |
| } |
| mutex_unlock(&ashmem_mutex); |
| |
| return lru_count; |
| } |
| |
| static struct shrinker ashmem_shrinker = { |
| .shrink = ashmem_shrink, |
| .seeks = DEFAULT_SEEKS * 4, |
| }; |
| |
| static int set_prot_mask(struct ashmem_area *asma, unsigned long prot) |
| { |
| int ret = 0; |
| |
| mutex_lock(&ashmem_mutex); |
| |
| /* the user can only remove, not add, protection bits */ |
| if (unlikely((asma->prot_mask & prot) != prot)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| /* does the application expect PROT_READ to imply PROT_EXEC? */ |
| if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) |
| prot |= PROT_EXEC; |
| |
| asma->prot_mask = prot; |
| |
| out: |
| mutex_unlock(&ashmem_mutex); |
| return ret; |
| } |
| |
| static int set_name(struct ashmem_area *asma, void __user *name) |
| { |
| int ret = 0; |
| |
| mutex_lock(&ashmem_mutex); |
| |
| /* cannot change an existing mapping's name */ |
| if (unlikely(asma->file)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (unlikely(copy_from_user(asma->name + ASHMEM_NAME_PREFIX_LEN, |
| name, ASHMEM_NAME_LEN))) |
| ret = -EFAULT; |
| asma->name[ASHMEM_FULL_NAME_LEN-1] = '\0'; |
| |
| out: |
| mutex_unlock(&ashmem_mutex); |
| |
| return ret; |
| } |
| |
| static int get_name(struct ashmem_area *asma, void __user *name) |
| { |
| int ret = 0; |
| |
| mutex_lock(&ashmem_mutex); |
| if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') { |
| size_t len; |
| |
| /* |
| * Copying only `len', instead of ASHMEM_NAME_LEN, bytes |
| * prevents us from revealing one user's stack to another. |
| */ |
| len = strlen(asma->name + ASHMEM_NAME_PREFIX_LEN) + 1; |
| if (unlikely(copy_to_user(name, |
| asma->name + ASHMEM_NAME_PREFIX_LEN, len))) |
| ret = -EFAULT; |
| } else { |
| if (unlikely(copy_to_user(name, ASHMEM_NAME_DEF, |
| sizeof(ASHMEM_NAME_DEF)))) |
| ret = -EFAULT; |
| } |
| mutex_unlock(&ashmem_mutex); |
| |
| return ret; |
| } |
| |
| /* |
| * ashmem_pin - pin the given ashmem region, returning whether it was |
| * previously purged (ASHMEM_WAS_PURGED) or not (ASHMEM_NOT_PURGED). |
| * |
| * Caller must hold ashmem_mutex. |
| */ |
| static int ashmem_pin(struct ashmem_area *asma, size_t pgstart, size_t pgend) |
| { |
| struct ashmem_range *range, *next; |
| int ret = ASHMEM_NOT_PURGED; |
| |
| list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) { |
| /* moved past last applicable page; we can short circuit */ |
| if (range_before_page(range, pgstart)) |
| break; |
| |
| /* |
| * The user can ask us to pin pages that span multiple ranges, |
| * or to pin pages that aren't even unpinned, so this is messy. |
| * |
| * Four cases: |
| * 1. The requested range subsumes an existing range, so we |
| * just remove the entire matching range. |
| * 2. The requested range overlaps the start of an existing |
| * range, so we just update that range. |
| * 3. The requested range overlaps the end of an existing |
| * range, so we just update that range. |
| * 4. The requested range punches a hole in an existing range, |
| * so we have to update one side of the range and then |
| * create a new range for the other side. |
| */ |
| if (page_range_in_range(range, pgstart, pgend)) { |
| ret |= range->purged; |
| |
| /* Case #1: Easy. Just nuke the whole thing. */ |
| if (page_range_subsumes_range(range, pgstart, pgend)) { |
| range_del(range); |
| continue; |
| } |
| |
| /* Case #2: We overlap from the start, so adjust it */ |
| if (range->pgstart >= pgstart) { |
| range_shrink(range, pgend + 1, range->pgend); |
| continue; |
| } |
| |
| /* Case #3: We overlap from the rear, so adjust it */ |
| if (range->pgend <= pgend) { |
| range_shrink(range, range->pgstart, pgstart-1); |
| continue; |
| } |
| |
| /* |
| * Case #4: We eat a chunk out of the middle. A bit |
| * more complicated, we allocate a new range for the |
| * second half and adjust the first chunk's endpoint. |
| */ |
| range_alloc(asma, range, range->purged, |
| pgend + 1, range->pgend); |
| range_shrink(range, range->pgstart, pgstart - 1); |
| break; |
| } |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * ashmem_unpin - unpin the given range of pages. Returns zero on success. |
| * |
| * Caller must hold ashmem_mutex. |
| */ |
| static int ashmem_unpin(struct ashmem_area *asma, size_t pgstart, size_t pgend) |
| { |
| struct ashmem_range *range, *next; |
| unsigned int purged = ASHMEM_NOT_PURGED; |
| |
| restart: |
| list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) { |
| /* short circuit: this is our insertion point */ |
| if (range_before_page(range, pgstart)) |
| break; |
| |
| /* |
| * The user can ask us to unpin pages that are already entirely |
| * or partially pinned. We handle those two cases here. |
| */ |
| if (page_range_subsumed_by_range(range, pgstart, pgend)) |
| return 0; |
| if (page_range_in_range(range, pgstart, pgend)) { |
| pgstart = min_t(size_t, range->pgstart, pgstart), |
| pgend = max_t(size_t, range->pgend, pgend); |
| purged |= range->purged; |
| range_del(range); |
| goto restart; |
| } |
| } |
| |
| return range_alloc(asma, range, purged, pgstart, pgend); |
| } |
| |
| /* |
| * ashmem_get_pin_status - Returns ASHMEM_IS_UNPINNED if _any_ pages in the |
| * given interval are unpinned and ASHMEM_IS_PINNED otherwise. |
| * |
| * Caller must hold ashmem_mutex. |
| */ |
| static int ashmem_get_pin_status(struct ashmem_area *asma, size_t pgstart, |
| size_t pgend) |
| { |
| struct ashmem_range *range; |
| int ret = ASHMEM_IS_PINNED; |
| |
| list_for_each_entry(range, &asma->unpinned_list, unpinned) { |
| if (range_before_page(range, pgstart)) |
| break; |
| if (page_range_in_range(range, pgstart, pgend)) { |
| ret = ASHMEM_IS_UNPINNED; |
| break; |
| } |
| } |
| |
| return ret; |
| } |
| |
| static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd, |
| void __user *p) |
| { |
| struct ashmem_pin pin; |
| size_t pgstart, pgend; |
| int ret = -EINVAL; |
| |
| if (unlikely(!asma->file)) |
| return -EINVAL; |
| |
| if (unlikely(copy_from_user(&pin, p, sizeof(pin)))) |
| return -EFAULT; |
| |
| /* per custom, you can pass zero for len to mean "everything onward" */ |
| if (!pin.len) |
| pin.len = PAGE_ALIGN(asma->size) - pin.offset; |
| |
| if (unlikely((pin.offset | pin.len) & ~PAGE_MASK)) |
| return -EINVAL; |
| |
| if (unlikely(((__u32) -1) - pin.offset < pin.len)) |
| return -EINVAL; |
| |
| if (unlikely(PAGE_ALIGN(asma->size) < pin.offset + pin.len)) |
| return -EINVAL; |
| |
| pgstart = pin.offset / PAGE_SIZE; |
| pgend = pgstart + (pin.len / PAGE_SIZE) - 1; |
| |
| mutex_lock(&ashmem_mutex); |
| |
| switch (cmd) { |
| case ASHMEM_PIN: |
| ret = ashmem_pin(asma, pgstart, pgend); |
| break; |
| case ASHMEM_UNPIN: |
| ret = ashmem_unpin(asma, pgstart, pgend); |
| break; |
| case ASHMEM_GET_PIN_STATUS: |
| ret = ashmem_get_pin_status(asma, pgstart, pgend); |
| break; |
| } |
| |
| mutex_unlock(&ashmem_mutex); |
| |
| return ret; |
| } |
| |
| #ifdef CONFIG_OUTER_CACHE |
| static unsigned int virtaddr_to_physaddr(unsigned int virtaddr) |
| { |
| unsigned int physaddr = 0; |
| pgd_t *pgd_ptr = NULL; |
| pud_t *pud_ptr = NULL; |
| pmd_t *pmd_ptr = NULL; |
| pte_t *pte_ptr = NULL, pte; |
| |
| spin_lock(¤t->mm->page_table_lock); |
| pgd_ptr = pgd_offset(current->mm, virtaddr); |
| if (pgd_none(*pgd_ptr) || pgd_bad(*pgd_ptr)) { |
| pr_err("Failed to convert virtaddr %x to pgd_ptr\n", |
| virtaddr); |
| goto done; |
| } |
| |
| pud_ptr = pud_offset(pgd_ptr, virtaddr); |
| if (pud_none(*pud_ptr) || pud_bad(*pud_ptr)) { |
| pr_err("Failed to convert pgd_ptr %p to pud_ptr\n", |
| (void *)pgd_ptr); |
| goto done; |
| } |
| |
| pmd_ptr = pmd_offset(pud_ptr, virtaddr); |
| if (pmd_none(*pmd_ptr) || pmd_bad(*pmd_ptr)) { |
| pr_err("Failed to convert pud_ptr %p to pmd_ptr\n", |
| (void *)pud_ptr); |
| goto done; |
| } |
| |
| pte_ptr = pte_offset_map(pmd_ptr, virtaddr); |
| if (!pte_ptr) { |
| pr_err("Failed to convert pmd_ptr %p to pte_ptr\n", |
| (void *)pmd_ptr); |
| goto done; |
| } |
| pte = *pte_ptr; |
| physaddr = pte_pfn(pte); |
| pte_unmap(pte_ptr); |
| done: |
| spin_unlock(¤t->mm->page_table_lock); |
| physaddr <<= PAGE_SHIFT; |
| return physaddr; |
| } |
| #endif |
| |
| static int ashmem_cache_op(struct ashmem_area *asma, |
| void (*cache_func)(unsigned long vstart, unsigned long length, |
| unsigned long pstart)) |
| { |
| int ret = 0; |
| struct vm_area_struct *vma; |
| #ifdef CONFIG_OUTER_CACHE |
| unsigned long vaddr; |
| #endif |
| if (!asma->vm_start) |
| return -EINVAL; |
| |
| down_read(¤t->mm->mmap_sem); |
| vma = find_vma(current->mm, asma->vm_start); |
| if (!vma) { |
| ret = -EINVAL; |
| goto done; |
| } |
| if (vma->vm_file != asma->file) { |
| ret = -EINVAL; |
| goto done; |
| } |
| if ((asma->vm_start + asma->size) > vma->vm_end) { |
| ret = -EINVAL; |
| goto done; |
| } |
| #ifndef CONFIG_OUTER_CACHE |
| cache_func(asma->vm_start, asma->size, 0); |
| #else |
| for (vaddr = asma->vm_start; vaddr < asma->vm_start + asma->size; |
| vaddr += PAGE_SIZE) { |
| unsigned long physaddr; |
| physaddr = virtaddr_to_physaddr(vaddr); |
| if (!physaddr) |
| return -EINVAL; |
| cache_func(vaddr, PAGE_SIZE, physaddr); |
| } |
| #endif |
| done: |
| up_read(¤t->mm->mmap_sem); |
| if (ret) |
| asma->vm_start = 0; |
| return ret; |
| } |
| |
| static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct ashmem_area *asma = file->private_data; |
| long ret = -ENOTTY; |
| |
| switch (cmd) { |
| case ASHMEM_SET_NAME: |
| ret = set_name(asma, (void __user *) arg); |
| break; |
| case ASHMEM_GET_NAME: |
| ret = get_name(asma, (void __user *) arg); |
| break; |
| case ASHMEM_SET_SIZE: |
| ret = -EINVAL; |
| if (!asma->file) { |
| ret = 0; |
| asma->size = (size_t) arg; |
| } |
| break; |
| case ASHMEM_GET_SIZE: |
| ret = asma->size; |
| break; |
| case ASHMEM_SET_PROT_MASK: |
| ret = set_prot_mask(asma, arg); |
| break; |
| case ASHMEM_GET_PROT_MASK: |
| ret = asma->prot_mask; |
| break; |
| case ASHMEM_PIN: |
| case ASHMEM_UNPIN: |
| case ASHMEM_GET_PIN_STATUS: |
| ret = ashmem_pin_unpin(asma, cmd, (void __user *) arg); |
| break; |
| case ASHMEM_PURGE_ALL_CACHES: |
| ret = -EPERM; |
| if (capable(CAP_SYS_ADMIN)) { |
| struct shrink_control sc = { |
| .gfp_mask = GFP_KERNEL, |
| .nr_to_scan = 0, |
| }; |
| ret = ashmem_shrink(&ashmem_shrinker, &sc); |
| sc.nr_to_scan = ret; |
| ashmem_shrink(&ashmem_shrinker, &sc); |
| } |
| break; |
| case ASHMEM_CACHE_FLUSH_RANGE: |
| ret = ashmem_cache_op(asma, &clean_and_invalidate_caches); |
| break; |
| case ASHMEM_CACHE_CLEAN_RANGE: |
| ret = ashmem_cache_op(asma, &clean_caches); |
| break; |
| case ASHMEM_CACHE_INV_RANGE: |
| ret = ashmem_cache_op(asma, &invalidate_caches); |
| break; |
| } |
| |
| return ret; |
| } |
| |
| static int is_ashmem_file(struct file *file) |
| { |
| char fname[256], *name; |
| name = dentry_path(file->f_dentry, fname, 256); |
| return strcmp(name, "/ashmem") ? 0 : 1; |
| } |
| |
| int get_ashmem_file(int fd, struct file **filp, struct file **vm_file, |
| unsigned long *len) |
| { |
| int ret = -1; |
| struct file *file = fget(fd); |
| *filp = NULL; |
| *vm_file = NULL; |
| if (unlikely(file == NULL)) { |
| pr_err("ashmem: %s: requested data from file " |
| "descriptor that doesn't exist.\n", __func__); |
| } else { |
| char currtask_name[FIELD_SIZEOF(struct task_struct, comm) + 1]; |
| pr_debug("filp %p rdev %d pid %u(%s) file %p(%ld)" |
| " dev id: %d\n", filp, |
| file->f_dentry->d_inode->i_rdev, |
| current->pid, get_task_comm(currtask_name, current), |
| file, file_count(file), |
| MINOR(file->f_dentry->d_inode->i_rdev)); |
| if (is_ashmem_file(file)) { |
| struct ashmem_area *asma = file->private_data; |
| *filp = file; |
| *vm_file = asma->file; |
| *len = asma->size; |
| ret = 0; |
| } else { |
| pr_err("file descriptor is not an ashmem " |
| "region fd: %d\n", fd); |
| fput(file); |
| } |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL(get_ashmem_file); |
| |
| void put_ashmem_file(struct file *file) |
| { |
| char currtask_name[FIELD_SIZEOF(struct task_struct, comm) + 1]; |
| pr_debug("rdev %d pid %u(%s) file %p(%ld)" " dev id: %d\n", |
| file->f_dentry->d_inode->i_rdev, current->pid, |
| get_task_comm(currtask_name, current), file, |
| file_count(file), MINOR(file->f_dentry->d_inode->i_rdev)); |
| if (file && is_ashmem_file(file)) |
| fput(file); |
| } |
| EXPORT_SYMBOL(put_ashmem_file); |
| |
| static const struct file_operations ashmem_fops = { |
| .owner = THIS_MODULE, |
| .open = ashmem_open, |
| .release = ashmem_release, |
| .read = ashmem_read, |
| .llseek = ashmem_llseek, |
| .mmap = ashmem_mmap, |
| .unlocked_ioctl = ashmem_ioctl, |
| .compat_ioctl = ashmem_ioctl, |
| }; |
| |
| static struct miscdevice ashmem_misc = { |
| .minor = MISC_DYNAMIC_MINOR, |
| .name = "ashmem", |
| .fops = &ashmem_fops, |
| }; |
| |
| static int __init ashmem_init(void) |
| { |
| int ret; |
| |
| ashmem_area_cachep = kmem_cache_create("ashmem_area_cache", |
| sizeof(struct ashmem_area), |
| 0, 0, NULL); |
| if (unlikely(!ashmem_area_cachep)) { |
| printk(KERN_ERR "ashmem: failed to create slab cache\n"); |
| return -ENOMEM; |
| } |
| |
| ashmem_range_cachep = kmem_cache_create("ashmem_range_cache", |
| sizeof(struct ashmem_range), |
| 0, 0, NULL); |
| if (unlikely(!ashmem_range_cachep)) { |
| printk(KERN_ERR "ashmem: failed to create slab cache\n"); |
| return -ENOMEM; |
| } |
| |
| ret = misc_register(&ashmem_misc); |
| if (unlikely(ret)) { |
| printk(KERN_ERR "ashmem: failed to register misc device!\n"); |
| return ret; |
| } |
| |
| register_shrinker(&ashmem_shrinker); |
| |
| printk(KERN_INFO "ashmem: initialized\n"); |
| |
| return 0; |
| } |
| |
| static void __exit ashmem_exit(void) |
| { |
| int ret; |
| |
| unregister_shrinker(&ashmem_shrinker); |
| |
| ret = misc_deregister(&ashmem_misc); |
| if (unlikely(ret)) |
| printk(KERN_ERR "ashmem: failed to unregister misc device!\n"); |
| |
| kmem_cache_destroy(ashmem_range_cachep); |
| kmem_cache_destroy(ashmem_area_cachep); |
| |
| printk(KERN_INFO "ashmem: unloaded\n"); |
| } |
| |
| module_init(ashmem_init); |
| module_exit(ashmem_exit); |
| |
| MODULE_LICENSE("GPL"); |