1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/dma-mapping.h>
3 #include <asm/iommu_table.h>
4 #include <linux/string.h>
5 #include <linux/kallsyms.h>
6
7 static struct iommu_table_entry * __init
find_dependents_of(struct iommu_table_entry * start,struct iommu_table_entry * finish,struct iommu_table_entry * q)8 find_dependents_of(struct iommu_table_entry *start,
9 struct iommu_table_entry *finish,
10 struct iommu_table_entry *q)
11 {
12 struct iommu_table_entry *p;
13
14 if (!q)
15 return NULL;
16
17 for (p = start; p < finish; p++)
18 if (p->detect == q->depend)
19 return p;
20
21 return NULL;
22 }
23
24
sort_iommu_table(struct iommu_table_entry * start,struct iommu_table_entry * finish)25 void __init sort_iommu_table(struct iommu_table_entry *start,
26 struct iommu_table_entry *finish) {
27
28 struct iommu_table_entry *p, *q, tmp;
29
30 for (p = start; p < finish; p++) {
31 again:
32 q = find_dependents_of(start, finish, p);
33 /* We are bit sneaky here. We use the memory address to figure
34 * out if the node we depend on is past our point, if so, swap.
35 */
36 if (q > p) {
37 tmp = *p;
38 memmove(p, q, sizeof(*p));
39 *q = tmp;
40 goto again;
41 }
42 }
43
44 }
45
46 #ifdef DEBUG
check_iommu_entries(struct iommu_table_entry * start,struct iommu_table_entry * finish)47 void __init check_iommu_entries(struct iommu_table_entry *start,
48 struct iommu_table_entry *finish)
49 {
50 struct iommu_table_entry *p, *q, *x;
51
52 /* Simple cyclic dependency checker. */
53 for (p = start; p < finish; p++) {
54 q = find_dependents_of(start, finish, p);
55 x = find_dependents_of(start, finish, q);
56 if (p == x) {
57 printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %pS depends on %pS and vice-versa. BREAKING IT.\n",
58 p->detect, q->detect);
59 /* Heavy handed way..*/
60 x->depend = NULL;
61 }
62 }
63
64 for (p = start; p < finish; p++) {
65 q = find_dependents_of(p, finish, p);
66 if (q && q > p) {
67 printk(KERN_ERR "EXECUTION ORDER INVALID! %pS should be called before %pS!\n",
68 p->detect, q->detect);
69 }
70 }
71 }
72 #else
check_iommu_entries(struct iommu_table_entry * start,struct iommu_table_entry * finish)73 void __init check_iommu_entries(struct iommu_table_entry *start,
74 struct iommu_table_entry *finish)
75 {
76 }
77 #endif
78