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
8 #define DEBUG 1
9
10 static struct iommu_table_entry * __init
find_dependents_of(struct iommu_table_entry * start,struct iommu_table_entry * finish,struct iommu_table_entry * q)11 find_dependents_of(struct iommu_table_entry *start,
12 struct iommu_table_entry *finish,
13 struct iommu_table_entry *q)
14 {
15 struct iommu_table_entry *p;
16
17 if (!q)
18 return NULL;
19
20 for (p = start; p < finish; p++)
21 if (p->detect == q->depend)
22 return p;
23
24 return NULL;
25 }
26
27
sort_iommu_table(struct iommu_table_entry * start,struct iommu_table_entry * finish)28 void __init sort_iommu_table(struct iommu_table_entry *start,
29 struct iommu_table_entry *finish) {
30
31 struct iommu_table_entry *p, *q, tmp;
32
33 for (p = start; p < finish; p++) {
34 again:
35 q = find_dependents_of(start, finish, p);
36 /* We are bit sneaky here. We use the memory address to figure
37 * out if the node we depend on is past our point, if so, swap.
38 */
39 if (q > p) {
40 tmp = *p;
41 memmove(p, q, sizeof(*p));
42 *q = tmp;
43 goto again;
44 }
45 }
46
47 }
48
49 #ifdef DEBUG
check_iommu_entries(struct iommu_table_entry * start,struct iommu_table_entry * finish)50 void __init check_iommu_entries(struct iommu_table_entry *start,
51 struct iommu_table_entry *finish)
52 {
53 struct iommu_table_entry *p, *q, *x;
54
55 /* Simple cyclic dependency checker. */
56 for (p = start; p < finish; p++) {
57 q = find_dependents_of(start, finish, p);
58 x = find_dependents_of(start, finish, q);
59 if (p == x) {
60 printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %pS depends on %pS and vice-versa. BREAKING IT.\n",
61 p->detect, q->detect);
62 /* Heavy handed way..*/
63 x->depend = NULL;
64 }
65 }
66
67 for (p = start; p < finish; p++) {
68 q = find_dependents_of(p, finish, p);
69 if (q && q > p) {
70 printk(KERN_ERR "EXECUTION ORDER INVALID! %pS should be called before %pS!\n",
71 p->detect, q->detect);
72 }
73 }
74 }
75 #else
check_iommu_entries(struct iommu_table_entry * start,struct iommu_table_entry * finish)76 void __init check_iommu_entries(struct iommu_table_entry *start,
77 struct iommu_table_entry *finish)
78 {
79 }
80 #endif
81
