1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Written by Pekka Paalanen, 2008-2009 <pq@iki.fi> |
4 | */ |
5 | |
6 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
7 | |
8 | #include <linux/module.h> |
9 | #include <linux/io.h> |
10 | #include <linux/mmiotrace.h> |
11 | #include <linux/security.h> |
12 | |
13 | static unsigned long mmio_address; |
14 | module_param_hw(mmio_address, ulong, iomem, 0); |
15 | MODULE_PARM_DESC(mmio_address, " Start address of the mapping of 16 kB " |
16 | "(or 8 MB if read_far is non-zero)." ); |
17 | |
18 | static unsigned long read_far = 0x400100; |
19 | module_param(read_far, ulong, 0); |
20 | MODULE_PARM_DESC(read_far, " Offset of a 32-bit read within 8 MB " |
21 | "(default: 0x400100)." ); |
22 | |
23 | static unsigned v16(unsigned i) |
24 | { |
25 | return i * 12 + 7; |
26 | } |
27 | |
28 | static unsigned v32(unsigned i) |
29 | { |
30 | return i * 212371 + 13; |
31 | } |
32 | |
33 | static void do_write_test(void __iomem *p) |
34 | { |
35 | unsigned int i; |
36 | pr_info("write test.\n" ); |
37 | mmiotrace_printk(fmt: "Write test.\n" ); |
38 | |
39 | for (i = 0; i < 256; i++) |
40 | iowrite8(i, p + i); |
41 | |
42 | for (i = 1024; i < (5 * 1024); i += 2) |
43 | iowrite16(v16(i), p + i); |
44 | |
45 | for (i = (5 * 1024); i < (16 * 1024); i += 4) |
46 | iowrite32(v32(i), p + i); |
47 | } |
48 | |
49 | static void do_read_test(void __iomem *p) |
50 | { |
51 | unsigned int i; |
52 | unsigned errs[3] = { 0 }; |
53 | pr_info("read test.\n" ); |
54 | mmiotrace_printk(fmt: "Read test.\n" ); |
55 | |
56 | for (i = 0; i < 256; i++) |
57 | if (ioread8(p + i) != i) |
58 | ++errs[0]; |
59 | |
60 | for (i = 1024; i < (5 * 1024); i += 2) |
61 | if (ioread16(p + i) != v16(i)) |
62 | ++errs[1]; |
63 | |
64 | for (i = (5 * 1024); i < (16 * 1024); i += 4) |
65 | if (ioread32(p + i) != v32(i)) |
66 | ++errs[2]; |
67 | |
68 | mmiotrace_printk(fmt: "Read errors: 8-bit %d, 16-bit %d, 32-bit %d.\n" , |
69 | errs[0], errs[1], errs[2]); |
70 | } |
71 | |
72 | static void do_read_far_test(void __iomem *p) |
73 | { |
74 | pr_info("read far test.\n" ); |
75 | mmiotrace_printk(fmt: "Read far test.\n" ); |
76 | |
77 | ioread32(p + read_far); |
78 | } |
79 | |
80 | static void do_test(unsigned long size) |
81 | { |
82 | void __iomem *p = ioremap(offset: mmio_address, size); |
83 | if (!p) { |
84 | pr_err("could not ioremap, aborting.\n" ); |
85 | return; |
86 | } |
87 | mmiotrace_printk(fmt: "ioremap returned %p.\n" , p); |
88 | do_write_test(p); |
89 | do_read_test(p); |
90 | if (read_far && read_far < size - 4) |
91 | do_read_far_test(p); |
92 | iounmap(addr: p); |
93 | } |
94 | |
95 | /* |
96 | * Tests how mmiotrace behaves in face of multiple ioremap / iounmaps in |
97 | * a short time. We had a bug in deferred freeing procedure which tried |
98 | * to free this region multiple times (ioremap can reuse the same address |
99 | * for many mappings). |
100 | */ |
101 | static void do_test_bulk_ioremapping(void) |
102 | { |
103 | void __iomem *p; |
104 | int i; |
105 | |
106 | for (i = 0; i < 10; ++i) { |
107 | p = ioremap(offset: mmio_address, PAGE_SIZE); |
108 | if (p) |
109 | iounmap(addr: p); |
110 | } |
111 | |
112 | /* Force freeing. If it will crash we will know why. */ |
113 | synchronize_rcu(); |
114 | } |
115 | |
116 | static int __init init(void) |
117 | { |
118 | unsigned long size = (read_far) ? (8 << 20) : (16 << 10); |
119 | int ret = security_locked_down(what: LOCKDOWN_MMIOTRACE); |
120 | |
121 | if (ret) |
122 | return ret; |
123 | |
124 | if (mmio_address == 0) { |
125 | pr_err("you have to use the module argument mmio_address.\n" ); |
126 | pr_err("DO NOT LOAD THIS MODULE UNLESS YOU REALLY KNOW WHAT YOU ARE DOING!\n" ); |
127 | return -ENXIO; |
128 | } |
129 | |
130 | pr_warn("WARNING: mapping %lu kB @ 0x%08lx in PCI address space, " |
131 | "and writing 16 kB of rubbish in there.\n" , |
132 | size >> 10, mmio_address); |
133 | do_test(size); |
134 | do_test_bulk_ioremapping(); |
135 | pr_info("All done.\n" ); |
136 | return 0; |
137 | } |
138 | |
139 | static void __exit cleanup(void) |
140 | { |
141 | pr_debug("unloaded.\n" ); |
142 | } |
143 | |
144 | module_init(init); |
145 | module_exit(cleanup); |
146 | MODULE_LICENSE("GPL" ); |
147 | |