Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1286 insertions, 0 deletions

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
new file mode 100644
index 0000000000..34c27223cb
--- /dev/null
+++ b/drivers/android/binder_alloc.c
@@ -0,0 +1,1286 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* binder_alloc.c
+ *
+ * Android IPC Subsystem
+ *
+ * Copyright (C) 2007-2017 Google, Inc.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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/ratelimit.h>
+#include <asm/cacheflush.h>
+#include <linux/uaccess.h>
+#include <linux/highmem.h>
+#include <linux/sizes.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_USER_ERROR             = 1U << 0,
+	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 = BINDER_DEBUG_USER_ERROR;
+
+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_ratelimited(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_prepare_to_free() - 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->mm))
+		mm = alloc->mm;
+
+	if (mm) {
+		mmap_write_lock(mm);
+		vma = alloc->vma;
+	}
+
+	if (!vma && need_mm) {
+		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
+				   "%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);
+	}
+	if (mm) {
+		mmap_write_unlock(mm);
+		mmput_async(mm);
+	}
+	return 0;
+
+free_range:
+	for (page_addr = end - PAGE_SIZE; 1; 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);
+		if (page_addr == start)
+			break;
+		continue;
+
+err_vm_insert_page_failed:
+		__free_page(page->page_ptr);
+		page->page_ptr = NULL;
+err_alloc_page_failed:
+err_page_ptr_cleared:
+		if (page_addr == start)
+			break;
+	}
+err_no_vma:
+	if (mm) {
+		mmap_write_unlock(mm);
+		mmput_async(mm);
+	}
+	return vma ? -ENOMEM : -ESRCH;
+}
+
+static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
+		struct vm_area_struct *vma)
+{
+	/* pairs with smp_load_acquire in binder_alloc_get_vma() */
+	smp_store_release(&alloc->vma, vma);
+}
+
+static inline struct vm_area_struct *binder_alloc_get_vma(
+		struct binder_alloc *alloc)
+{
+	/* pairs with smp_store_release in binder_alloc_set_vma() */
+	return smp_load_acquire(&alloc->vma);
+}
+
+static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
+{
+	/*
+	 * Find the amount and size of buffers allocated by the current caller;
+	 * The idea is that once we cross the threshold, whoever is responsible
+	 * for the low async space is likely to try to send another async txn,
+	 * and at some point we'll catch them in the act. This is more efficient
+	 * than keeping a map per pid.
+	 */
+	struct rb_node *n;
+	struct binder_buffer *buffer;
+	size_t total_alloc_size = 0;
+	size_t num_buffers = 0;
+
+	for (n = rb_first(&alloc->allocated_buffers); n != NULL;
+		 n = rb_next(n)) {
+		buffer = rb_entry(n, struct binder_buffer, rb_node);
+		if (buffer->pid != pid)
+			continue;
+		if (!buffer->async_transaction)
+			continue;
+		total_alloc_size += binder_alloc_buffer_size(alloc, buffer);
+		num_buffers++;
+	}
+
+	/*
+	 * Warn if this pid has more than 50 transactions, or more than 50% of
+	 * async space (which is 25% of total buffer size). Oneway spam is only
+	 * detected when the threshold is exceeded.
+	 */
+	if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
+		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
+			     "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
+			      alloc->pid, pid, num_buffers, total_alloc_size);
+		if (!alloc->oneway_spam_detected) {
+			alloc->oneway_spam_detected = true;
+			return true;
+		}
+	}
+	return false;
+}
+
+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,
+				int pid)
+{
+	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;
+
+	/* Check binder_alloc is fully initialized */
+	if (!binder_alloc_get_vma(alloc)) {
+		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
+				   "%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);
+	}
+
+	/* Pad 0-size buffers so they get assigned unique addresses */
+	size = max(size, sizeof(void *));
+
+	if (is_async && alloc->free_async_space < size) {
+		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);
+	}
+
+	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;
+		}
+		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
+				   "%d: binder_alloc_buf size %zd failed, no address space\n",
+				   alloc->pid, size);
+		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
+				   "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;
+	buffer->pid = pid;
+	buffer->oneway_spam_suspect = false;
+	if (is_async) {
+		alloc->free_async_space -= size;
+		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);
+		if (alloc->free_async_space < alloc->buffer_size / 10) {
+			/*
+			 * Start detecting spammers once we have less than 20%
+			 * of async space left (which is less than 10% of total
+			 * buffer size).
+			 */
+			buffer->oneway_spam_suspect = debug_low_async_space_locked(alloc, pid);
+		} else {
+			alloc->oneway_spam_detected = false;
+		}
+	}
+	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
+ * @pid:				pid to attribute allocation to (used for debugging)
+ *
+ * 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 %ERR_PTR(-errno) 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,
+					   int pid)
+{
+	struct binder_buffer *buffer;
+
+	mutex_lock(&alloc->mutex);
+	buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
+					     extra_buffers_size, is_async, pid);
+	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 += buffer_size;
+		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);
+}
+
+static void binder_alloc_clear_buf(struct binder_alloc *alloc,
+				   struct binder_buffer *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_buf()
+ */
+void binder_alloc_free_buf(struct binder_alloc *alloc,
+			    struct binder_buffer *buffer)
+{
+	/*
+	 * We could eliminate the call to binder_alloc_clear_buf()
+	 * from binder_alloc_deferred_release() by moving this to
+	 * binder_free_buf_locked(). However, that could
+	 * increase contention for the alloc mutex if clear_on_free
+	 * is used frequently for large buffers. The mutex is not
+	 * needed for correctness here.
+	 */
+	if (buffer->clear_on_free) {
+		binder_alloc_clear_buf(alloc, buffer);
+		buffer->clear_on_free = false;
+	}
+	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;
+
+	if (unlikely(vma->vm_mm != alloc->mm)) {
+		ret = -EINVAL;
+		failure_string = "invalid vma->vm_mm";
+		goto err_invalid_mm;
+	}
+
+	mutex_lock(&binder_alloc_mmap_lock);
+	if (alloc->buffer_size) {
+		ret = -EBUSY;
+		failure_string = "already mapped";
+		goto err_already_mapped;
+	}
+	alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
+				   SZ_4M);
+	mutex_unlock(&binder_alloc_mmap_lock);
+
+	alloc->buffer = (void __user *)vma->vm_start;
+
+	alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
+			       sizeof(alloc->pages[0]),
+			       GFP_KERNEL);
+	if (alloc->pages == NULL) {
+		ret = -ENOMEM;
+		failure_string = "alloc page array";
+		goto err_alloc_pages_failed;
+	}
+
+	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;
+
+	/* Signal binder_alloc is fully initialized */
+	binder_alloc_set_vma(alloc, vma);
+
+	return 0;
+
+err_alloc_buf_struct_failed:
+	kfree(alloc->pages);
+	alloc->pages = NULL;
+err_alloc_pages_failed:
+	alloc->buffer = NULL;
+	mutex_lock(&binder_alloc_mmap_lock);
+	alloc->buffer_size = 0;
+err_already_mapped:
+	mutex_unlock(&binder_alloc_mmap_lock);
+err_invalid_mm:
+	binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
+			   "%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);
+
+		if (buffer->clear_on_free) {
+			binder_alloc_clear_buf(alloc, buffer);
+			buffer->clear_on_free = false;
+		}
+		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->mm)
+		mmdrop(alloc->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);
+	/*
+	 * Make sure the binder_alloc is fully initialized, otherwise we might
+	 * read inconsistent state.
+	 */
+	if (binder_alloc_get_vma(alloc) != NULL) {
+		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)
+	__must_hold(lock)
+{
+	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;
+
+	mm = alloc->mm;
+	if (!mmget_not_zero(mm))
+		goto err_mmget;
+	if (!mmap_read_trylock(mm))
+		goto err_mmap_read_lock_failed;
+	vma = vma_lookup(mm, page_addr);
+	if (vma && vma != binder_alloc_get_vma(alloc))
+		goto err_invalid_vma;
+
+	list_lru_isolate(lru, item);
+	spin_unlock(lock);
+
+	if (vma) {
+		trace_binder_unmap_user_start(alloc, index);
+
+		zap_page_range_single(vma, page_addr, PAGE_SIZE, NULL);
+
+		trace_binder_unmap_user_end(alloc, index);
+	}
+	mmap_read_unlock(mm);
+	mmput_async(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_invalid_vma:
+	mmap_read_unlock(mm);
+err_mmap_read_lock_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)
+{
+	return list_lru_count(&binder_alloc_lru);
+}
+
+static unsigned long
+binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
+{
+	return list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
+			    NULL, sc->nr_to_scan);
+}
+
+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;
+	alloc->mm = current->mm;
+	mmgrab(alloc->mm);
+	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, "android-binder");
+		if (ret)
+			list_lru_destroy(&binder_alloc_lru);
+	}
+	return ret;
+}
+
+void binder_alloc_shrinker_exit(void)
+{
+	unregister_shrinker(&binder_shrinker);
+	list_lru_destroy(&binder_alloc_lru);
+}
+
+/**
+ * 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_clear_buf() - zero out buffer
+ * @alloc: binder_alloc for this proc
+ * @buffer: binder buffer to be cleared
+ *
+ * memset the given buffer to 0
+ */
+static void binder_alloc_clear_buf(struct binder_alloc *alloc,
+				   struct binder_buffer *buffer)
+{
+	size_t bytes = binder_alloc_buffer_size(alloc, buffer);
+	binder_size_t buffer_offset = 0;
+
+	while (bytes) {
+		unsigned long size;
+		struct page *page;
+		pgoff_t pgoff;
+
+		page = binder_alloc_get_page(alloc, buffer,
+					     buffer_offset, &pgoff);
+		size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
+		memset_page(page, pgoff, 0, size);
+		bytes -= size;
+		buffer_offset += size;
+	}
+}
+
+/**
+ * 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_local_page(page) + pgoff;
+		ret = copy_from_user(kptr, from, size);
+		kunmap_local(kptr);
+		if (ret)
+			return bytes - size + ret;
+		bytes -= size;
+		from += size;
+		buffer_offset += size;
+	}
+	return 0;
+}
+
+static int 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 */
+	if (!check_buffer(alloc, buffer, buffer_offset, bytes))
+		return -EINVAL;
+
+	while (bytes) {
+		unsigned long size;
+		struct page *page;
+		pgoff_t pgoff;
+
+		page = binder_alloc_get_page(alloc, buffer,
+					     buffer_offset, &pgoff);
+		size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
+		if (to_buffer)
+			memcpy_to_page(page, pgoff, ptr, size);
+		else
+			memcpy_from_page(ptr, page, pgoff, size);
+		bytes -= size;
+		pgoff = 0;
+		ptr = ptr + size;
+		buffer_offset += size;
+	}
+	return 0;
+}
+
+int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
+				struct binder_buffer *buffer,
+				binder_size_t buffer_offset,
+				void *src,
+				size_t bytes)
+{
+	return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
+					   src, bytes);
+}
+
+int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
+				  void *dest,
+				  struct binder_buffer *buffer,
+				  binder_size_t buffer_offset,
+				  size_t bytes)
+{
+	return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
+					   dest, bytes);
+}
+