1// SPDX-License-Identifier: GPL-2.0
2/*
3 * DMABUF System heap exporter
4 *
5 * Copyright (C) 2011 Google, Inc.
6 * Copyright (C) 2019 Linaro Ltd.
7 */
8
9#include <linux/dma-buf.h>
10#include <linux/dma-mapping.h>
11#include <linux/dma-heap.h>
12#include <linux/err.h>
13#include <linux/highmem.h>
14#include <linux/mm.h>
15#include <linux/module.h>
16#include <linux/scatterlist.h>
17#include <linux/slab.h>
18#include <linux/sched/signal.h>
19#include <asm/page.h>
20
21#include "heap-helpers.h"
22
23struct dma_heap *sys_heap;
24
25static void system_heap_free(struct heap_helper_buffer *buffer)
26{
27	pgoff_t pg;
28
29	for (pg = 0; pg < buffer->pagecount; pg++)
30		__free_page(buffer->pages[pg]);
31	kfree(buffer->pages);
32	kfree(buffer);
33}
34
35static int system_heap_allocate(struct dma_heap *heap,
36				unsigned long len,
37				unsigned long fd_flags,
38				unsigned long heap_flags)
39{
40	struct heap_helper_buffer *helper_buffer;
41	struct dma_buf *dmabuf;
42	int ret = -ENOMEM;
43	pgoff_t pg;
44
45	helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
46	if (!helper_buffer)
47		return -ENOMEM;
48
49	init_heap_helper_buffer(helper_buffer, system_heap_free);
50	helper_buffer->heap = heap;
51	helper_buffer->size = len;
52
53	helper_buffer->pagecount = len / PAGE_SIZE;
54	helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
55					     sizeof(*helper_buffer->pages),
56					     GFP_KERNEL);
57	if (!helper_buffer->pages) {
58		ret = -ENOMEM;
59		goto err0;
60	}
61
62	for (pg = 0; pg < helper_buffer->pagecount; pg++) {
63		/*
64		 * Avoid trying to allocate memory if the process
65		 * has been killed by by SIGKILL
66		 */
67		if (fatal_signal_pending(current))
68			goto err1;
69
70		helper_buffer->pages[pg] = alloc_page(GFP_KERNEL | __GFP_ZERO);
71		if (!helper_buffer->pages[pg])
72			goto err1;
73	}
74
75	/* create the dmabuf */
76	dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
77	if (IS_ERR(dmabuf)) {
78		ret = PTR_ERR(dmabuf);
79		goto err1;
80	}
81
82	helper_buffer->dmabuf = dmabuf;
83
84	ret = dma_buf_fd(dmabuf, fd_flags);
85	if (ret < 0) {
86		dma_buf_put(dmabuf);
87		/* just return, as put will call release and that will free */
88		return ret;
89	}
90
91	return ret;
92
93err1:
94	while (pg > 0)
95		__free_page(helper_buffer->pages[--pg]);
96	kfree(helper_buffer->pages);
97err0:
98	kfree(helper_buffer);
99
100	return ret;
101}
102
103static const struct dma_heap_ops system_heap_ops = {
104	.allocate = system_heap_allocate,
105};
106
107static int system_heap_create(void)
108{
109	struct dma_heap_export_info exp_info;
110	int ret = 0;
111
112	exp_info.name = "system";
113	exp_info.ops = &system_heap_ops;
114	exp_info.priv = NULL;
115
116	sys_heap = dma_heap_add(&exp_info);
117	if (IS_ERR(sys_heap))
118		ret = PTR_ERR(sys_heap);
119
120	return ret;
121}
122module_init(system_heap_create);
123MODULE_LICENSE("GPL v2");
124