// SPDX-License-Identifier: GPL-2.0-only
/* binder_alloc_selftest.c
*
* Android IPC Subsystem
*
* Copyright (C) 2017 Google, Inc.
*/
#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: The number of enum values in &buf_end_align_type.
* It is used for controlling loop termination.
*/
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)
{
unsigned long page_addr;
unsigned long end;
int page_index;
end = PAGE_ALIGN(buffer->user_data + size);
page_addr = buffer->user_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_freelist))) {
list_lru_walk(&binder_freelist, 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_freelist))
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);
}
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