1 files changed, 310 insertions, 0 deletions
diff --git a/drivers/android/binder_alloc_selftest.c b/drivers/android/binder_alloc_selftest.c
new file mode 100644
index 000000000000..8bd7bcef967d
--- /dev/null
+++ b/drivers/android/binder_alloc_selftest.c
@@ -0,0 +1,310 @@
+/* binder_alloc_selftest.c
+ *
+ * Android IPC Subsystem
+ *
+ * Copyright (C) 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 <linux/mm_types.h>
+#include <linux/err.h>
+#include "binder_alloc.h"
+
+#define BUFFER_NUM 5
+#define BUFFER_MIN_SIZE (PAGE_SIZE / 8)
+
+static bool binder_selftest_run = true;
+static int binder_selftest_failures;
+static DEFINE_MUTEX(binder_selftest_lock);
+
+/**
+ * enum buf_end_align_type - Page alignment of a buffer
+ * end with regard to the end of the previous buffer.
+ *
+ * In the pictures below, buf2 refers to the buffer we
+ * are aligning. buf1 refers to previous buffer by addr.
+ * Symbol [ means the start of a buffer, ] means the end
+ * of a buffer, and | means page boundaries.
+ */
+enum buf_end_align_type {
+	/**
+	 * @SAME_PAGE_UNALIGNED: The end of this buffer is on
+	 * the same page as the end of the previous buffer and
+	 * is not page aligned. Examples:
+	 * buf1 ][ buf2 ][ ...
+	 * buf1 ]|[ buf2 ][ ...
+	 */
+	SAME_PAGE_UNALIGNED = 0,
+	/**
+	 * @SAME_PAGE_ALIGNED: When the end of the previous buffer
+	 * is not page aligned, the end of this buffer is on the
+	 * same page as the end of the previous buffer and is page
+	 * aligned. When the previous buffer is page aligned, the
+	 * end of this buffer is aligned to the next page boundary.
+	 * Examples:
+	 * buf1 ][ buf2 ]| ...
+	 * buf1 ]|[ buf2 ]| ...
+	 */
+	SAME_PAGE_ALIGNED,
+	/**
+	 * @NEXT_PAGE_UNALIGNED: The end of this buffer is on
+	 * the page next to the end of the previous buffer and
+	 * is not page aligned. Examples:
+	 * buf1 ][ buf2 | buf2 ][ ...
+	 * buf1 ]|[ buf2 | buf2 ][ ...
+	 */
+	NEXT_PAGE_UNALIGNED,
+	/**
+	 * @NEXT_PAGE_ALIGNED: The end of this buffer is on
+	 * the page next to the end of the previous buffer and
+	 * is page aligned. Examples:
+	 * buf1 ][ buf2 | buf2 ]| ...
+	 * buf1 ]|[ buf2 | buf2 ]| ...
+	 */
+	NEXT_PAGE_ALIGNED,
+	/**
+	 * @NEXT_NEXT_UNALIGNED: The end of this buffer is on
+	 * the page that follows the page after the end of the
+	 * previous buffer and is not page aligned. Examples:
+	 * buf1 ][ buf2 | buf2 | buf2 ][ ...
+	 * buf1 ]|[ buf2 | buf2 | buf2 ][ ...
+	 */
+	NEXT_NEXT_UNALIGNED,
+	LOOP_END,
+};
+
+static void pr_err_size_seq(size_t *sizes, int *seq)
+{
+	int i;
+
+	pr_err("alloc sizes: ");
+	for (i = 0; i < BUFFER_NUM; i++)
+		pr_cont("[%zu]", sizes[i]);
+	pr_cont("\n");
+	pr_err("free seq: ");
+	for (i = 0; i < BUFFER_NUM; i++)
+		pr_cont("[%d]", seq[i]);
+	pr_cont("\n");
+}
+
+static bool check_buffer_pages_allocated(struct binder_alloc *alloc,
+					 struct binder_buffer *buffer,
+					 size_t size)
+{
+	void *page_addr, *end;
+	int page_index;
+
+	end = (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
+	page_addr = buffer->data;
+	for (; page_addr < end; page_addr += PAGE_SIZE) {
+		page_index = (page_addr - alloc->buffer) / PAGE_SIZE;
+		if (!alloc->pages[page_index].page_ptr ||
+		    !list_empty(&alloc->pages[page_index].lru)) {
+			pr_err("expect alloc but is %s at page index %d\n",
+			       alloc->pages[page_index].page_ptr ?
+			       "lru" : "free", page_index);
+			return false;
+		}
+	}
+	return true;
+}
+
+static void binder_selftest_alloc_buf(struct binder_alloc *alloc,
+				      struct binder_buffer *buffers[],
+				      size_t *sizes, int *seq)
+{
+	int i;
+
+	for (i = 0; i < BUFFER_NUM; i++) {
+		buffers[i] = binder_alloc_new_buf(alloc, sizes[i], 0, 0, 0);
+		if (IS_ERR(buffers[i]) ||
+		    !check_buffer_pages_allocated(alloc, buffers[i],
+						  sizes[i])) {
+			pr_err_size_seq(sizes, seq);
+			binder_selftest_failures++;
+		}
+	}
+}
+
+static void binder_selftest_free_buf(struct binder_alloc *alloc,
+				     struct binder_buffer *buffers[],
+				     size_t *sizes, int *seq, size_t end)
+{
+	int i;
+
+	for (i = 0; i < BUFFER_NUM; i++)
+		binder_alloc_free_buf(alloc, buffers[seq[i]]);
+
+	for (i = 0; i < end / PAGE_SIZE; i++) {
+		/**
+		 * Error message on a free page can be false positive
+		 * if binder shrinker ran during binder_alloc_free_buf
+		 * calls above.
+		 */
+		if (list_empty(&alloc->pages[i].lru)) {
+			pr_err_size_seq(sizes, seq);
+			pr_err("expect lru but is %s at page index %d\n",
+			       alloc->pages[i].page_ptr ? "alloc" : "free", i);
+			binder_selftest_failures++;
+		}
+	}
+}
+
+static void binder_selftest_free_page(struct binder_alloc *alloc)
+{
+	int i;
+	unsigned long count;
+
+	while ((count = list_lru_count(&binder_alloc_lru))) {
+		list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
+			      NULL, count);
+	}
+
+	for (i = 0; i < (alloc->buffer_size / PAGE_SIZE); i++) {
+		if (alloc->pages[i].page_ptr) {
+			pr_err("expect free but is %s at page index %d\n",
+			       list_empty(&alloc->pages[i].lru) ?
+			       "alloc" : "lru", i);
+			binder_selftest_failures++;
+		}
+	}
+}
+
+static void binder_selftest_alloc_free(struct binder_alloc *alloc,
+				       size_t *sizes, int *seq, size_t end)
+{
+	struct binder_buffer *buffers[BUFFER_NUM];
+
+	binder_selftest_alloc_buf(alloc, buffers, sizes, seq);
+	binder_selftest_free_buf(alloc, buffers, sizes, seq, end);
+
+	/* Allocate from lru. */
+	binder_selftest_alloc_buf(alloc, buffers, sizes, seq);
+	if (list_lru_count(&binder_alloc_lru))
+		pr_err("lru list should be empty but is not\n");
+
+	binder_selftest_free_buf(alloc, buffers, sizes, seq, end);
+	binder_selftest_free_page(alloc);
+}
+
+static bool is_dup(int *seq, int index, int val)
+{
+	int i;
+
+	for (i = 0; i < index; i++) {
+		if (seq[i] == val)
+			return true;
+	}
+	return false;
+}
+
+/* Generate BUFFER_NUM factorial free orders. */
+static void binder_selftest_free_seq(struct binder_alloc *alloc,
+				     size_t *sizes, int *seq,
+				     int index, size_t end)
+{
+	int i;
+
+	if (index == BUFFER_NUM) {
+		binder_selftest_alloc_free(alloc, sizes, seq, end);
+		return;
+	}
+	for (i = 0; i < BUFFER_NUM; i++) {
+		if (is_dup(seq, index, i))
+			continue;
+		seq[index] = i;
+		binder_selftest_free_seq(alloc, sizes, seq, index + 1, end);
+	}
+}
+
+static void binder_selftest_alloc_size(struct binder_alloc *alloc,
+				       size_t *end_offset)
+{
+	int i;
+	int seq[BUFFER_NUM] = {0};
+	size_t front_sizes[BUFFER_NUM];
+	size_t back_sizes[BUFFER_NUM];
+	size_t last_offset, offset = 0;
+
+	for (i = 0; i < BUFFER_NUM; i++) {
+		last_offset = offset;
+		offset = end_offset[i];
+		front_sizes[i] = offset - last_offset;
+		back_sizes[BUFFER_NUM - i - 1] = front_sizes[i];
+	}
+	/*
+	 * Buffers share the first or last few pages.
+	 * Only BUFFER_NUM - 1 buffer sizes are adjustable since
+	 * we need one giant buffer before getting to the last page.
+	 */
+	back_sizes[0] += alloc->buffer_size - end_offset[BUFFER_NUM - 1];
+	binder_selftest_free_seq(alloc, front_sizes, seq, 0,
+				 end_offset[BUFFER_NUM - 1]);
+	binder_selftest_free_seq(alloc, back_sizes, seq, 0, alloc->buffer_size);
+}
+
+static void binder_selftest_alloc_offset(struct binder_alloc *alloc,
+					 size_t *end_offset, int index)
+{
+	int align;
+	size_t end, prev;
+
+	if (index == BUFFER_NUM) {
+		binder_selftest_alloc_size(alloc, end_offset);
+		return;
+	}
+	prev = index == 0 ? 0 : end_offset[index - 1];
+	end = prev;
+
+	BUILD_BUG_ON(BUFFER_MIN_SIZE * BUFFER_NUM >= PAGE_SIZE);
+
+	for (align = SAME_PAGE_UNALIGNED; align < LOOP_END; align++) {
+		if (align % 2)
+			end = ALIGN(end, PAGE_SIZE);
+		else
+			end += BUFFER_MIN_SIZE;
+		end_offset[index] = end;
+		binder_selftest_alloc_offset(alloc, end_offset, index + 1);
+	}
+}
+
+/**
+ * binder_selftest_alloc() - Test alloc and free of buffer pages.
+ * @alloc: Pointer to alloc struct.
+ *
+ * Allocate BUFFER_NUM buffers to cover all page alignment cases,
+ * then free them in all orders possible. Check that pages are
+ * correctly allocated, put onto lru when buffers are freed, and
+ * are freed when binder_alloc_free_page is called.
+ */
+void binder_selftest_alloc(struct binder_alloc *alloc)
+{
+	size_t end_offset[BUFFER_NUM];
+
+	if (!binder_selftest_run)
+		return;
+	mutex_lock(&binder_selftest_lock);
+	if (!binder_selftest_run || !alloc->vma)
+		goto done;
+	pr_info("STARTED\n");
+	binder_selftest_alloc_offset(alloc, end_offset, 0);
+	binder_selftest_run = false;
+	if (binder_selftest_failures > 0)
+		pr_info("%d tests FAILED\n", binder_selftest_failures);
+	else
+		pr_info("PASSED\n");
+
+done:
+	mutex_unlock(&binder_selftest_lock);
+}