| /* binder_alloc.c |
| * |
| * Android IPC Subsystem |
| * |
| * Copyright (C) 2007-2017 Google, Inc. |
| * |
| * 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. |
| * |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <asm/cacheflush.h> |
| #include <linux/list.h> |
| #include <linux/sched/mm.h> |
| #include <linux/module.h> |
| #include <linux/rtmutex.h> |
| #include <linux/rbtree.h> |
| #include <linux/seq_file.h> |
| #include <linux/vmalloc.h> |
| #include <linux/slab.h> |
| #include <linux/sched.h> |
| #include <linux/list_lru.h> |
| #include <linux/uaccess.h> |
| #include <linux/highmem.h> |
| #include "binder_alloc.h" |
| #include "binder_trace.h" |
| |
| struct list_lru binder_alloc_lru; |
| |
| static DEFINE_MUTEX(binder_alloc_mmap_lock); |
| |
| enum { |
| BINDER_DEBUG_OPEN_CLOSE = 1U << 1, |
| BINDER_DEBUG_BUFFER_ALLOC = 1U << 2, |
| BINDER_DEBUG_BUFFER_ALLOC_ASYNC = 1U << 3, |
| }; |
| static uint32_t binder_alloc_debug_mask; |
| |
| module_param_named(debug_mask, binder_alloc_debug_mask, |
| uint, 0644); |
| |
| #define binder_alloc_debug(mask, x...) \ |
| do { \ |
| if (binder_alloc_debug_mask & mask) \ |
| pr_info(x); \ |
| } while (0) |
| |
| static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer) |
| { |
| return list_entry(buffer->entry.next, struct binder_buffer, entry); |
| } |
| |
| static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer) |
| { |
| return list_entry(buffer->entry.prev, struct binder_buffer, entry); |
| } |
| |
| static size_t binder_alloc_buffer_size(struct binder_alloc *alloc, |
| struct binder_buffer *buffer) |
| { |
| if (list_is_last(&buffer->entry, &alloc->buffers)) |
| return alloc->buffer + alloc->buffer_size - buffer->user_data; |
| return binder_buffer_next(buffer)->user_data - buffer->user_data; |
| } |
| |
| static void binder_insert_free_buffer(struct binder_alloc *alloc, |
| struct binder_buffer *new_buffer) |
| { |
| struct rb_node **p = &alloc->free_buffers.rb_node; |
| struct rb_node *parent = NULL; |
| struct binder_buffer *buffer; |
| size_t buffer_size; |
| size_t new_buffer_size; |
| |
| BUG_ON(!new_buffer->free); |
| |
| new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer); |
| |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: add free buffer, size %zd, at %pK\n", |
| alloc->pid, new_buffer_size, new_buffer); |
| |
| while (*p) { |
| parent = *p; |
| buffer = rb_entry(parent, struct binder_buffer, rb_node); |
| BUG_ON(!buffer->free); |
| |
| buffer_size = binder_alloc_buffer_size(alloc, buffer); |
| |
| if (new_buffer_size < buffer_size) |
| p = &parent->rb_left; |
| else |
| p = &parent->rb_right; |
| } |
| rb_link_node(&new_buffer->rb_node, parent, p); |
| rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers); |
| } |
| |
| static void binder_insert_allocated_buffer_locked( |
| struct binder_alloc *alloc, struct binder_buffer *new_buffer) |
| { |
| struct rb_node **p = &alloc->allocated_buffers.rb_node; |
| struct rb_node *parent = NULL; |
| struct binder_buffer *buffer; |
| |
| BUG_ON(new_buffer->free); |
| |
| while (*p) { |
| parent = *p; |
| buffer = rb_entry(parent, struct binder_buffer, rb_node); |
| BUG_ON(buffer->free); |
| |
| if (new_buffer->user_data < buffer->user_data) |
| p = &parent->rb_left; |
| else if (new_buffer->user_data > buffer->user_data) |
| p = &parent->rb_right; |
| else |
| BUG(); |
| } |
| rb_link_node(&new_buffer->rb_node, parent, p); |
| rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers); |
| } |
| |
| static struct binder_buffer *binder_alloc_prepare_to_free_locked( |
| struct binder_alloc *alloc, |
| uintptr_t user_ptr) |
| { |
| struct rb_node *n = alloc->allocated_buffers.rb_node; |
| struct binder_buffer *buffer; |
| void __user *uptr; |
| |
| uptr = (void __user *)user_ptr; |
| |
| while (n) { |
| buffer = rb_entry(n, struct binder_buffer, rb_node); |
| BUG_ON(buffer->free); |
| |
| if (uptr < buffer->user_data) |
| n = n->rb_left; |
| else if (uptr > buffer->user_data) |
| n = n->rb_right; |
| else { |
| /* |
| * Guard against user threads attempting to |
| * free the buffer when in use by kernel or |
| * after it's already been freed. |
| */ |
| if (!buffer->allow_user_free) |
| return ERR_PTR(-EPERM); |
| buffer->allow_user_free = 0; |
| return buffer; |
| } |
| } |
| return NULL; |
| } |
| |
| /** |
| * binder_alloc_buffer_lookup() - get buffer given user ptr |
| * @alloc: binder_alloc for this proc |
| * @user_ptr: User pointer to buffer data |
| * |
| * Validate userspace pointer to buffer data and return buffer corresponding to |
| * that user pointer. Search the rb tree for buffer that matches user data |
| * pointer. |
| * |
| * Return: Pointer to buffer or NULL |
| */ |
| struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc, |
| uintptr_t user_ptr) |
| { |
| struct binder_buffer *buffer; |
| |
| mutex_lock(&alloc->mutex); |
| buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr); |
| mutex_unlock(&alloc->mutex); |
| return buffer; |
| } |
| |
| static int binder_update_page_range(struct binder_alloc *alloc, int allocate, |
| void __user *start, void __user *end) |
| { |
| void __user *page_addr; |
| unsigned long user_page_addr; |
| struct binder_lru_page *page; |
| struct vm_area_struct *vma = NULL; |
| struct mm_struct *mm = NULL; |
| bool need_mm = false; |
| |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: %s pages %pK-%pK\n", alloc->pid, |
| allocate ? "allocate" : "free", start, end); |
| |
| if (end <= start) |
| return 0; |
| |
| trace_binder_update_page_range(alloc, allocate, start, end); |
| |
| if (allocate == 0) |
| goto free_range; |
| |
| for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) { |
| page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE]; |
| if (!page->page_ptr) { |
| need_mm = true; |
| break; |
| } |
| } |
| |
| if (need_mm && mmget_not_zero(alloc->vma_vm_mm)) |
| mm = alloc->vma_vm_mm; |
| |
| if (mm) { |
| down_read(&mm->mmap_sem); |
| vma = alloc->vma; |
| } |
| |
| if (!vma && need_mm) { |
| pr_err("%d: binder_alloc_buf failed to map pages in userspace, no vma\n", |
| alloc->pid); |
| goto err_no_vma; |
| } |
| |
| for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) { |
| int ret; |
| bool on_lru; |
| size_t index; |
| |
| index = (page_addr - alloc->buffer) / PAGE_SIZE; |
| page = &alloc->pages[index]; |
| |
| if (page->page_ptr) { |
| trace_binder_alloc_lru_start(alloc, index); |
| |
| on_lru = list_lru_del(&binder_alloc_lru, &page->lru); |
| WARN_ON(!on_lru); |
| |
| trace_binder_alloc_lru_end(alloc, index); |
| continue; |
| } |
| |
| if (WARN_ON(!vma)) |
| goto err_page_ptr_cleared; |
| |
| trace_binder_alloc_page_start(alloc, index); |
| page->page_ptr = alloc_page(GFP_KERNEL | |
| __GFP_HIGHMEM | |
| __GFP_ZERO); |
| if (!page->page_ptr) { |
| pr_err("%d: binder_alloc_buf failed for page at %pK\n", |
| alloc->pid, page_addr); |
| goto err_alloc_page_failed; |
| } |
| page->alloc = alloc; |
| INIT_LIST_HEAD(&page->lru); |
| |
| user_page_addr = (uintptr_t)page_addr; |
| ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr); |
| if (ret) { |
| pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n", |
| alloc->pid, user_page_addr); |
| goto err_vm_insert_page_failed; |
| } |
| |
| if (index + 1 > alloc->pages_high) |
| alloc->pages_high = index + 1; |
| |
| trace_binder_alloc_page_end(alloc, index); |
| /* vm_insert_page does not seem to increment the refcount */ |
| } |
| if (mm) { |
| up_read(&mm->mmap_sem); |
| mmput(mm); |
| } |
| return 0; |
| |
| free_range: |
| for (page_addr = end - PAGE_SIZE; page_addr >= start; |
| page_addr -= PAGE_SIZE) { |
| bool ret; |
| size_t index; |
| |
| index = (page_addr - alloc->buffer) / PAGE_SIZE; |
| page = &alloc->pages[index]; |
| |
| trace_binder_free_lru_start(alloc, index); |
| |
| ret = list_lru_add(&binder_alloc_lru, &page->lru); |
| WARN_ON(!ret); |
| |
| trace_binder_free_lru_end(alloc, index); |
| continue; |
| |
| err_vm_insert_page_failed: |
| __free_page(page->page_ptr); |
| page->page_ptr = NULL; |
| err_alloc_page_failed: |
| err_page_ptr_cleared: |
| ; |
| } |
| err_no_vma: |
| if (mm) { |
| up_read(&mm->mmap_sem); |
| mmput(mm); |
| } |
| return vma ? -ENOMEM : -ESRCH; |
| } |
| |
| static inline void binder_alloc_set_vma(struct binder_alloc *alloc, |
| struct vm_area_struct *vma) |
| { |
| if (vma) |
| alloc->vma_vm_mm = vma->vm_mm; |
| /* |
| * If we see alloc->vma is not NULL, buffer data structures set up |
| * completely. Look at smp_rmb side binder_alloc_get_vma. |
| * We also want to guarantee new alloc->vma_vm_mm is always visible |
| * if alloc->vma is set. |
| */ |
| smp_wmb(); |
| alloc->vma = vma; |
| } |
| |
| static inline struct vm_area_struct *binder_alloc_get_vma( |
| struct binder_alloc *alloc) |
| { |
| struct vm_area_struct *vma = NULL; |
| |
| if (alloc->vma) { |
| /* Look at description in binder_alloc_set_vma */ |
| smp_rmb(); |
| vma = alloc->vma; |
| } |
| return vma; |
| } |
| |
| static struct binder_buffer *binder_alloc_new_buf_locked( |
| struct binder_alloc *alloc, |
| size_t data_size, |
| size_t offsets_size, |
| size_t extra_buffers_size, |
| int is_async) |
| { |
| struct rb_node *n = alloc->free_buffers.rb_node; |
| struct binder_buffer *buffer; |
| size_t buffer_size; |
| struct rb_node *best_fit = NULL; |
| void __user *has_page_addr; |
| void __user *end_page_addr; |
| size_t size, data_offsets_size; |
| int ret; |
| |
| if (!binder_alloc_get_vma(alloc)) { |
| pr_err("%d: binder_alloc_buf, no vma\n", |
| alloc->pid); |
| return ERR_PTR(-ESRCH); |
| } |
| |
| data_offsets_size = ALIGN(data_size, sizeof(void *)) + |
| ALIGN(offsets_size, sizeof(void *)); |
| |
| if (data_offsets_size < data_size || data_offsets_size < offsets_size) { |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: got transaction with invalid size %zd-%zd\n", |
| alloc->pid, data_size, offsets_size); |
| return ERR_PTR(-EINVAL); |
| } |
| size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *)); |
| if (size < data_offsets_size || size < extra_buffers_size) { |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: got transaction with invalid extra_buffers_size %zd\n", |
| alloc->pid, extra_buffers_size); |
| return ERR_PTR(-EINVAL); |
| } |
| if (is_async && |
| alloc->free_async_space < size + sizeof(struct binder_buffer)) { |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: binder_alloc_buf size %zd failed, no async space left\n", |
| alloc->pid, size); |
| return ERR_PTR(-ENOSPC); |
| } |
| |
| /* Pad 0-size buffers so they get assigned unique addresses */ |
| size = max(size, sizeof(void *)); |
| |
| while (n) { |
| buffer = rb_entry(n, struct binder_buffer, rb_node); |
| BUG_ON(!buffer->free); |
| buffer_size = binder_alloc_buffer_size(alloc, buffer); |
| |
| if (size < buffer_size) { |
| best_fit = n; |
| n = n->rb_left; |
| } else if (size > buffer_size) |
| n = n->rb_right; |
| else { |
| best_fit = n; |
| break; |
| } |
| } |
| if (best_fit == NULL) { |
| size_t allocated_buffers = 0; |
| size_t largest_alloc_size = 0; |
| size_t total_alloc_size = 0; |
| size_t free_buffers = 0; |
| size_t largest_free_size = 0; |
| size_t total_free_size = 0; |
| |
| for (n = rb_first(&alloc->allocated_buffers); n != NULL; |
| n = rb_next(n)) { |
| buffer = rb_entry(n, struct binder_buffer, rb_node); |
| buffer_size = binder_alloc_buffer_size(alloc, buffer); |
| allocated_buffers++; |
| total_alloc_size += buffer_size; |
| if (buffer_size > largest_alloc_size) |
| largest_alloc_size = buffer_size; |
| } |
| for (n = rb_first(&alloc->free_buffers); n != NULL; |
| n = rb_next(n)) { |
| buffer = rb_entry(n, struct binder_buffer, rb_node); |
| buffer_size = binder_alloc_buffer_size(alloc, buffer); |
| free_buffers++; |
| total_free_size += buffer_size; |
| if (buffer_size > largest_free_size) |
| largest_free_size = buffer_size; |
| } |
| pr_err("%d: binder_alloc_buf size %zd failed, no address space\n", |
| alloc->pid, size); |
| pr_err("allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n", |
| total_alloc_size, allocated_buffers, largest_alloc_size, |
| total_free_size, free_buffers, largest_free_size); |
| return ERR_PTR(-ENOSPC); |
| } |
| if (n == NULL) { |
| buffer = rb_entry(best_fit, struct binder_buffer, rb_node); |
| buffer_size = binder_alloc_buffer_size(alloc, buffer); |
| } |
| |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n", |
| alloc->pid, size, buffer, buffer_size); |
| |
| has_page_addr = (void __user *) |
| (((uintptr_t)buffer->user_data + buffer_size) & PAGE_MASK); |
| WARN_ON(n && buffer_size != size); |
| end_page_addr = |
| (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data + size); |
| if (end_page_addr > has_page_addr) |
| end_page_addr = has_page_addr; |
| ret = binder_update_page_range(alloc, 1, (void __user *) |
| PAGE_ALIGN((uintptr_t)buffer->user_data), end_page_addr); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| if (buffer_size != size) { |
| struct binder_buffer *new_buffer; |
| |
| new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); |
| if (!new_buffer) { |
| pr_err("%s: %d failed to alloc new buffer struct\n", |
| __func__, alloc->pid); |
| goto err_alloc_buf_struct_failed; |
| } |
| new_buffer->user_data = (u8 __user *)buffer->user_data + size; |
| list_add(&new_buffer->entry, &buffer->entry); |
| new_buffer->free = 1; |
| binder_insert_free_buffer(alloc, new_buffer); |
| } |
| |
| rb_erase(best_fit, &alloc->free_buffers); |
| buffer->free = 0; |
| buffer->allow_user_free = 0; |
| binder_insert_allocated_buffer_locked(alloc, buffer); |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: binder_alloc_buf size %zd got %pK\n", |
| alloc->pid, size, buffer); |
| buffer->data_size = data_size; |
| buffer->offsets_size = offsets_size; |
| buffer->async_transaction = is_async; |
| buffer->extra_buffers_size = extra_buffers_size; |
| if (is_async) { |
| alloc->free_async_space -= size + sizeof(struct binder_buffer); |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC, |
| "%d: binder_alloc_buf size %zd async free %zd\n", |
| alloc->pid, size, alloc->free_async_space); |
| } |
| return buffer; |
| |
| err_alloc_buf_struct_failed: |
| binder_update_page_range(alloc, 0, (void __user *) |
| PAGE_ALIGN((uintptr_t)buffer->user_data), |
| end_page_addr); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| /** |
| * binder_alloc_new_buf() - Allocate a new binder buffer |
| * @alloc: binder_alloc for this proc |
| * @data_size: size of user data buffer |
| * @offsets_size: user specified buffer offset |
| * @extra_buffers_size: size of extra space for meta-data (eg, security context) |
| * @is_async: buffer for async transaction |
| * |
| * Allocate a new buffer given the requested sizes. Returns |
| * the kernel version of the buffer pointer. The size allocated |
| * is the sum of the three given sizes (each rounded up to |
| * pointer-sized boundary) |
| * |
| * Return: The allocated buffer or %NULL if error |
| */ |
| struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc, |
| size_t data_size, |
| size_t offsets_size, |
| size_t extra_buffers_size, |
| int is_async) |
| { |
| struct binder_buffer *buffer; |
| |
| mutex_lock(&alloc->mutex); |
| buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size, |
| extra_buffers_size, is_async); |
| mutex_unlock(&alloc->mutex); |
| return buffer; |
| } |
| |
| static void __user *buffer_start_page(struct binder_buffer *buffer) |
| { |
| return (void __user *)((uintptr_t)buffer->user_data & PAGE_MASK); |
| } |
| |
| static void __user *prev_buffer_end_page(struct binder_buffer *buffer) |
| { |
| return (void __user *) |
| (((uintptr_t)(buffer->user_data) - 1) & PAGE_MASK); |
| } |
| |
| static void binder_delete_free_buffer(struct binder_alloc *alloc, |
| struct binder_buffer *buffer) |
| { |
| struct binder_buffer *prev, *next = NULL; |
| bool to_free = true; |
| BUG_ON(alloc->buffers.next == &buffer->entry); |
| prev = binder_buffer_prev(buffer); |
| BUG_ON(!prev->free); |
| if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) { |
| to_free = false; |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: merge free, buffer %pK share page with %pK\n", |
| alloc->pid, buffer->user_data, |
| prev->user_data); |
| } |
| |
| if (!list_is_last(&buffer->entry, &alloc->buffers)) { |
| next = binder_buffer_next(buffer); |
| if (buffer_start_page(next) == buffer_start_page(buffer)) { |
| to_free = false; |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: merge free, buffer %pK share page with %pK\n", |
| alloc->pid, |
| buffer->user_data, |
| next->user_data); |
| } |
| } |
| |
| if (PAGE_ALIGNED(buffer->user_data)) { |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: merge free, buffer start %pK is page aligned\n", |
| alloc->pid, buffer->user_data); |
| to_free = false; |
| } |
| |
| if (to_free) { |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: merge free, buffer %pK do not share page with %pK or %pK\n", |
| alloc->pid, buffer->user_data, |
| prev->user_data, |
| next ? next->user_data : NULL); |
| binder_update_page_range(alloc, 0, buffer_start_page(buffer), |
| buffer_start_page(buffer) + PAGE_SIZE); |
| } |
| list_del(&buffer->entry); |
| kfree(buffer); |
| } |
| |
| static void binder_free_buf_locked(struct binder_alloc *alloc, |
| struct binder_buffer *buffer) |
| { |
| size_t size, buffer_size; |
| |
| buffer_size = binder_alloc_buffer_size(alloc, buffer); |
| |
| size = ALIGN(buffer->data_size, sizeof(void *)) + |
| ALIGN(buffer->offsets_size, sizeof(void *)) + |
| ALIGN(buffer->extra_buffers_size, sizeof(void *)); |
| |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%d: binder_free_buf %pK size %zd buffer_size %zd\n", |
| alloc->pid, buffer, size, buffer_size); |
| |
| BUG_ON(buffer->free); |
| BUG_ON(size > buffer_size); |
| BUG_ON(buffer->transaction != NULL); |
| BUG_ON(buffer->user_data < alloc->buffer); |
| BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size); |
| |
| if (buffer->async_transaction) { |
| alloc->free_async_space += size + sizeof(struct binder_buffer); |
| |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC, |
| "%d: binder_free_buf size %zd async free %zd\n", |
| alloc->pid, size, alloc->free_async_space); |
| } |
| |
| binder_update_page_range(alloc, 0, |
| (void __user *)PAGE_ALIGN((uintptr_t)buffer->user_data), |
| (void __user *)(((uintptr_t) |
| buffer->user_data + buffer_size) & PAGE_MASK)); |
| |
| rb_erase(&buffer->rb_node, &alloc->allocated_buffers); |
| buffer->free = 1; |
| if (!list_is_last(&buffer->entry, &alloc->buffers)) { |
| struct binder_buffer *next = binder_buffer_next(buffer); |
| |
| if (next->free) { |
| rb_erase(&next->rb_node, &alloc->free_buffers); |
| binder_delete_free_buffer(alloc, next); |
| } |
| } |
| if (alloc->buffers.next != &buffer->entry) { |
| struct binder_buffer *prev = binder_buffer_prev(buffer); |
| |
| if (prev->free) { |
| binder_delete_free_buffer(alloc, buffer); |
| rb_erase(&prev->rb_node, &alloc->free_buffers); |
| buffer = prev; |
| } |
| } |
| binder_insert_free_buffer(alloc, buffer); |
| } |
| |
| /** |
| * binder_alloc_free_buf() - free a binder buffer |
| * @alloc: binder_alloc for this proc |
| * @buffer: kernel pointer to buffer |
| * |
| * Free the buffer allocated via binder_alloc_new_buffer() |
| */ |
| void binder_alloc_free_buf(struct binder_alloc *alloc, |
| struct binder_buffer *buffer) |
| { |
| mutex_lock(&alloc->mutex); |
| binder_free_buf_locked(alloc, buffer); |
| mutex_unlock(&alloc->mutex); |
| } |
| |
| /** |
| * binder_alloc_mmap_handler() - map virtual address space for proc |
| * @alloc: alloc structure for this proc |
| * @vma: vma passed to mmap() |
| * |
| * Called by binder_mmap() to initialize the space specified in |
| * vma for allocating binder buffers |
| * |
| * Return: |
| * 0 = success |
| * -EBUSY = address space already mapped |
| * -ENOMEM = failed to map memory to given address space |
| */ |
| int binder_alloc_mmap_handler(struct binder_alloc *alloc, |
| struct vm_area_struct *vma) |
| { |
| int ret; |
| const char *failure_string; |
| struct binder_buffer *buffer; |
| |
| mutex_lock(&binder_alloc_mmap_lock); |
| if (alloc->buffer) { |
| ret = -EBUSY; |
| failure_string = "already mapped"; |
| goto err_already_mapped; |
| } |
| |
| alloc->buffer = (void __user *)vma->vm_start; |
| mutex_unlock(&binder_alloc_mmap_lock); |
| |
| alloc->pages = kzalloc(sizeof(alloc->pages[0]) * |
| ((vma->vm_end - vma->vm_start) / PAGE_SIZE), |
| GFP_KERNEL); |
| if (alloc->pages == NULL) { |
| ret = -ENOMEM; |
| failure_string = "alloc page array"; |
| goto err_alloc_pages_failed; |
| } |
| alloc->buffer_size = vma->vm_end - vma->vm_start; |
| |
| buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); |
| if (!buffer) { |
| ret = -ENOMEM; |
| failure_string = "alloc buffer struct"; |
| goto err_alloc_buf_struct_failed; |
| } |
| |
| buffer->user_data = alloc->buffer; |
| list_add(&buffer->entry, &alloc->buffers); |
| buffer->free = 1; |
| binder_insert_free_buffer(alloc, buffer); |
| alloc->free_async_space = alloc->buffer_size / 2; |
| binder_alloc_set_vma(alloc, vma); |
| mmgrab(alloc->vma_vm_mm); |
| |
| return 0; |
| |
| err_alloc_buf_struct_failed: |
| kfree(alloc->pages); |
| alloc->pages = NULL; |
| err_alloc_pages_failed: |
| mutex_lock(&binder_alloc_mmap_lock); |
| alloc->buffer = NULL; |
| err_already_mapped: |
| mutex_unlock(&binder_alloc_mmap_lock); |
| pr_err("%s: %d %lx-%lx %s failed %d\n", __func__, |
| alloc->pid, vma->vm_start, vma->vm_end, failure_string, ret); |
| return ret; |
| } |
| |
| |
| void binder_alloc_deferred_release(struct binder_alloc *alloc) |
| { |
| struct rb_node *n; |
| int buffers, page_count; |
| struct binder_buffer *buffer; |
| |
| buffers = 0; |
| mutex_lock(&alloc->mutex); |
| BUG_ON(alloc->vma); |
| |
| while ((n = rb_first(&alloc->allocated_buffers))) { |
| buffer = rb_entry(n, struct binder_buffer, rb_node); |
| |
| /* Transaction should already have been freed */ |
| BUG_ON(buffer->transaction); |
| |
| binder_free_buf_locked(alloc, buffer); |
| buffers++; |
| } |
| |
| while (!list_empty(&alloc->buffers)) { |
| buffer = list_first_entry(&alloc->buffers, |
| struct binder_buffer, entry); |
| WARN_ON(!buffer->free); |
| |
| list_del(&buffer->entry); |
| WARN_ON_ONCE(!list_empty(&alloc->buffers)); |
| kfree(buffer); |
| } |
| |
| page_count = 0; |
| if (alloc->pages) { |
| int i; |
| |
| for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) { |
| void __user *page_addr; |
| bool on_lru; |
| |
| if (!alloc->pages[i].page_ptr) |
| continue; |
| |
| on_lru = list_lru_del(&binder_alloc_lru, |
| &alloc->pages[i].lru); |
| page_addr = alloc->buffer + i * PAGE_SIZE; |
| binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC, |
| "%s: %d: page %d at %pK %s\n", |
| __func__, alloc->pid, i, page_addr, |
| on_lru ? "on lru" : "active"); |
| __free_page(alloc->pages[i].page_ptr); |
| page_count++; |
| } |
| kfree(alloc->pages); |
| } |
| mutex_unlock(&alloc->mutex); |
| if (alloc->vma_vm_mm) |
| mmdrop(alloc->vma_vm_mm); |
| |
| binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE, |
| "%s: %d buffers %d, pages %d\n", |
| __func__, alloc->pid, buffers, page_count); |
| } |
| |
| static void print_binder_buffer(struct seq_file *m, const char *prefix, |
| struct binder_buffer *buffer) |
| { |
| seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n", |
| prefix, buffer->debug_id, buffer->user_data, |
| buffer->data_size, buffer->offsets_size, |
| buffer->extra_buffers_size, |
| buffer->transaction ? "active" : "delivered"); |
| } |
| |
| /** |
| * binder_alloc_print_allocated() - print buffer info |
| * @m: seq_file for output via seq_printf() |
| * @alloc: binder_alloc for this proc |
| * |
| * Prints information about every buffer associated with |
| * the binder_alloc state to the given seq_file |
| */ |
| void binder_alloc_print_allocated(struct seq_file *m, |
| struct binder_alloc *alloc) |
| { |
| struct rb_node *n; |
| |
| mutex_lock(&alloc->mutex); |
| for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n)) |
| print_binder_buffer(m, " buffer", |
| rb_entry(n, struct binder_buffer, rb_node)); |
| mutex_unlock(&alloc->mutex); |
| } |
| |
| /** |
| * binder_alloc_print_pages() - print page usage |
| * @m: seq_file for output via seq_printf() |
| * @alloc: binder_alloc for this proc |
| */ |
| void binder_alloc_print_pages(struct seq_file *m, |
| struct binder_alloc *alloc) |
| { |
| struct binder_lru_page *page; |
| int i; |
| int active = 0; |
| int lru = 0; |
| int free = 0; |
| |
| mutex_lock(&alloc->mutex); |
| for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) { |
| page = &alloc->pages[i]; |
| if (!page->page_ptr) |
| free++; |
| else if (list_empty(&page->lru)) |
| active++; |
| else |
| lru++; |
| } |
| mutex_unlock(&alloc->mutex); |
| seq_printf(m, " pages: %d:%d:%d\n", active, lru, free); |
| seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high); |
| } |
| |
| /** |
| * binder_alloc_get_allocated_count() - return count of buffers |
| * @alloc: binder_alloc for this proc |
| * |
| * Return: count of allocated buffers |
| */ |
| int binder_alloc_get_allocated_count(struct binder_alloc *alloc) |
| { |
| struct rb_node *n; |
| int count = 0; |
| |
| mutex_lock(&alloc->mutex); |
| for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n)) |
| count++; |
| mutex_unlock(&alloc->mutex); |
| return count; |
| } |
| |
| |
| /** |
| * binder_alloc_vma_close() - invalidate address space |
| * @alloc: binder_alloc for this proc |
| * |
| * Called from binder_vma_close() when releasing address space. |
| * Clears alloc->vma to prevent new incoming transactions from |
| * allocating more buffers. |
| */ |
| void binder_alloc_vma_close(struct binder_alloc *alloc) |
| { |
| binder_alloc_set_vma(alloc, NULL); |
| } |
| |
| /** |
| * binder_alloc_free_page() - shrinker callback to free pages |
| * @item: item to free |
| * @lock: lock protecting the item |
| * @cb_arg: callback argument |
| * |
| * Called from list_lru_walk() in binder_shrink_scan() to free |
| * up pages when the system is under memory pressure. |
| */ |
| enum lru_status binder_alloc_free_page(struct list_head *item, |
| struct list_lru_one *lru, |
| spinlock_t *lock, |
| void *cb_arg) |
| { |
| struct mm_struct *mm = NULL; |
| struct binder_lru_page *page = container_of(item, |
| struct binder_lru_page, |
| lru); |
| struct binder_alloc *alloc; |
| uintptr_t page_addr; |
| size_t index; |
| struct vm_area_struct *vma; |
| |
| alloc = page->alloc; |
| if (!mutex_trylock(&alloc->mutex)) |
| goto err_get_alloc_mutex_failed; |
| |
| if (!page->page_ptr) |
| goto err_page_already_freed; |
| |
| index = page - alloc->pages; |
| page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE; |
| vma = binder_alloc_get_vma(alloc); |
| if (vma) { |
| if (!mmget_not_zero(alloc->vma_vm_mm)) |
| goto err_mmget; |
| mm = alloc->vma_vm_mm; |
| if (!down_write_trylock(&mm->mmap_sem)) |
| goto err_down_write_mmap_sem_failed; |
| } |
| |
| list_lru_isolate(lru, item); |
| spin_unlock(lock); |
| |
| if (vma) { |
| trace_binder_unmap_user_start(alloc, index); |
| |
| zap_page_range(vma, page_addr, PAGE_SIZE); |
| |
| trace_binder_unmap_user_end(alloc, index); |
| |
| up_write(&mm->mmap_sem); |
| mmput(mm); |
| } |
| |
| trace_binder_unmap_kernel_start(alloc, index); |
| |
| __free_page(page->page_ptr); |
| page->page_ptr = NULL; |
| |
| trace_binder_unmap_kernel_end(alloc, index); |
| |
| spin_lock(lock); |
| mutex_unlock(&alloc->mutex); |
| return LRU_REMOVED_RETRY; |
| |
| err_down_write_mmap_sem_failed: |
| mmput_async(mm); |
| err_mmget: |
| err_page_already_freed: |
| mutex_unlock(&alloc->mutex); |
| err_get_alloc_mutex_failed: |
| return LRU_SKIP; |
| } |
| |
| static unsigned long |
| binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc) |
| { |
| unsigned long ret = list_lru_count(&binder_alloc_lru); |
| return ret; |
| } |
| |
| static unsigned long |
| binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) |
| { |
| unsigned long ret; |
| |
| ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page, |
| NULL, sc->nr_to_scan); |
| return ret; |
| } |
| |
| static struct shrinker binder_shrinker = { |
| .count_objects = binder_shrink_count, |
| .scan_objects = binder_shrink_scan, |
| .seeks = DEFAULT_SEEKS, |
| }; |
| |
| /** |
| * binder_alloc_init() - called by binder_open() for per-proc initialization |
| * @alloc: binder_alloc for this proc |
| * |
| * Called from binder_open() to initialize binder_alloc fields for |
| * new binder proc |
| */ |
| void binder_alloc_init(struct binder_alloc *alloc) |
| { |
| alloc->pid = current->group_leader->pid; |
| mutex_init(&alloc->mutex); |
| INIT_LIST_HEAD(&alloc->buffers); |
| } |
| |
| int binder_alloc_shrinker_init(void) |
| { |
| int ret = list_lru_init(&binder_alloc_lru); |
| |
| if (ret == 0) { |
| ret = register_shrinker(&binder_shrinker); |
| if (ret) |
| list_lru_destroy(&binder_alloc_lru); |
| } |
| return ret; |
| } |
| |
| /** |
| * check_buffer() - verify that buffer/offset is safe to access |
| * @alloc: binder_alloc for this proc |
| * @buffer: binder buffer to be accessed |
| * @offset: offset into @buffer data |
| * @bytes: bytes to access from offset |
| * |
| * Check that the @offset/@bytes are within the size of the given |
| * @buffer and that the buffer is currently active and not freeable. |
| * Offsets must also be multiples of sizeof(u32). The kernel is |
| * allowed to touch the buffer in two cases: |
| * |
| * 1) when the buffer is being created: |
| * (buffer->free == 0 && buffer->allow_user_free == 0) |
| * 2) when the buffer is being torn down: |
| * (buffer->free == 0 && buffer->transaction == NULL). |
| * |
| * Return: true if the buffer is safe to access |
| */ |
| static inline bool check_buffer(struct binder_alloc *alloc, |
| struct binder_buffer *buffer, |
| binder_size_t offset, size_t bytes) |
| { |
| size_t buffer_size = binder_alloc_buffer_size(alloc, buffer); |
| |
| return buffer_size >= bytes && |
| offset <= buffer_size - bytes && |
| IS_ALIGNED(offset, sizeof(u32)) && |
| !buffer->free && |
| (!buffer->allow_user_free || !buffer->transaction); |
| } |
| |
| /** |
| * binder_alloc_get_page() - get kernel pointer for given buffer offset |
| * @alloc: binder_alloc for this proc |
| * @buffer: binder buffer to be accessed |
| * @buffer_offset: offset into @buffer data |
| * @pgoffp: address to copy final page offset to |
| * |
| * Lookup the struct page corresponding to the address |
| * at @buffer_offset into @buffer->user_data. If @pgoffp is not |
| * NULL, the byte-offset into the page is written there. |
| * |
| * The caller is responsible to ensure that the offset points |
| * to a valid address within the @buffer and that @buffer is |
| * not freeable by the user. Since it can't be freed, we are |
| * guaranteed that the corresponding elements of @alloc->pages[] |
| * cannot change. |
| * |
| * Return: struct page |
| */ |
| static struct page *binder_alloc_get_page(struct binder_alloc *alloc, |
| struct binder_buffer *buffer, |
| binder_size_t buffer_offset, |
| pgoff_t *pgoffp) |
| { |
| binder_size_t buffer_space_offset = buffer_offset + |
| (buffer->user_data - alloc->buffer); |
| pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK; |
| size_t index = buffer_space_offset >> PAGE_SHIFT; |
| struct binder_lru_page *lru_page; |
| |
| lru_page = &alloc->pages[index]; |
| *pgoffp = pgoff; |
| return lru_page->page_ptr; |
| } |
| |
| /** |
| * binder_alloc_copy_user_to_buffer() - copy src user to tgt user |
| * @alloc: binder_alloc for this proc |
| * @buffer: binder buffer to be accessed |
| * @buffer_offset: offset into @buffer data |
| * @from: userspace pointer to source buffer |
| * @bytes: bytes to copy |
| * |
| * Copy bytes from source userspace to target buffer. |
| * |
| * Return: bytes remaining to be copied |
| */ |
| unsigned long |
| binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc, |
| struct binder_buffer *buffer, |
| binder_size_t buffer_offset, |
| const void __user *from, |
| size_t bytes) |
| { |
| if (!check_buffer(alloc, buffer, buffer_offset, bytes)) |
| return bytes; |
| |
| while (bytes) { |
| unsigned long size; |
| unsigned long ret; |
| struct page *page; |
| pgoff_t pgoff; |
| void *kptr; |
| |
| page = binder_alloc_get_page(alloc, buffer, |
| buffer_offset, &pgoff); |
| size = min_t(size_t, bytes, PAGE_SIZE - pgoff); |
| kptr = kmap(page) + pgoff; |
| ret = copy_from_user(kptr, from, size); |
| kunmap(page); |
| if (ret) |
| return bytes - size + ret; |
| bytes -= size; |
| from += size; |
| buffer_offset += size; |
| } |
| return 0; |
| } |
| |
| static void binder_alloc_do_buffer_copy(struct binder_alloc *alloc, |
| bool to_buffer, |
| struct binder_buffer *buffer, |
| binder_size_t buffer_offset, |
| void *ptr, |
| size_t bytes) |
| { |
| /* All copies must be 32-bit aligned and 32-bit size */ |
| BUG_ON(!check_buffer(alloc, buffer, buffer_offset, bytes)); |
| |
| while (bytes) { |
| unsigned long size; |
| struct page *page; |
| pgoff_t pgoff; |
| void *tmpptr; |
| void *base_ptr; |
| |
| page = binder_alloc_get_page(alloc, buffer, |
| buffer_offset, &pgoff); |
| size = min_t(size_t, bytes, PAGE_SIZE - pgoff); |
| base_ptr = kmap_atomic(page); |
| tmpptr = base_ptr + pgoff; |
| if (to_buffer) |
| memcpy(tmpptr, ptr, size); |
| else |
| memcpy(ptr, tmpptr, size); |
| /* |
| * kunmap_atomic() takes care of flushing the cache |
| * if this device has VIVT cache arch |
| */ |
| kunmap_atomic(base_ptr); |
| bytes -= size; |
| pgoff = 0; |
| ptr = ptr + size; |
| buffer_offset += size; |
| } |
| } |
| |
| void binder_alloc_copy_to_buffer(struct binder_alloc *alloc, |
| struct binder_buffer *buffer, |
| binder_size_t buffer_offset, |
| void *src, |
| size_t bytes) |
| { |
| binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset, |
| src, bytes); |
| } |
| |
| void binder_alloc_copy_from_buffer(struct binder_alloc *alloc, |
| void *dest, |
| struct binder_buffer *buffer, |
| binder_size_t buffer_offset, |
| size_t bytes) |
| { |
| binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset, |
| dest, bytes); |
| } |
| |