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");