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Commit | Line | Data |
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3d88958e JD |
1 | /* Copyright (C) 2005 - 2008 Jeff Dike <jdike@{linux.intel,addtoit}.com> */ |
2 | ||
567b5650 PBG |
3 | /* Much of this ripped from drivers/char/hw_random.c, see there for other |
4 | * copyright. | |
5 | * | |
6 | * This software may be used and distributed according to the terms | |
7 | * of the GNU General Public License, incorporated herein by reference. | |
8 | */ | |
174cd4b1 | 9 | #include <linux/sched/signal.h> |
1da177e4 LT |
10 | #include <linux/module.h> |
11 | #include <linux/fs.h> | |
5d33e4d7 | 12 | #include <linux/interrupt.h> |
1da177e4 | 13 | #include <linux/miscdevice.h> |
72d3e093 | 14 | #include <linux/hw_random.h> |
1da177e4 | 15 | #include <linux/delay.h> |
7c0f6ba6 | 16 | #include <linux/uaccess.h> |
ff6a1798 | 17 | #include <init.h> |
37185b33 AV |
18 | #include <irq_kern.h> |
19 | #include <os.h> | |
1da177e4 LT |
20 | |
21 | /* | |
72d3e093 | 22 | * core module information |
1da177e4 | 23 | */ |
5d33e4d7 | 24 | #define RNG_MODULE_NAME "hw_random" |
1da177e4 | 25 | |
730760e9 JD |
26 | /* Changed at init time, in the non-modular case, and at module load |
27 | * time, in the module case. Presumably, the module subsystem | |
28 | * protects against a module being loaded twice at the same time. | |
29 | */ | |
1da177e4 | 30 | static int random_fd = -1; |
72d3e093 CO |
31 | static struct hwrng hwrng = { 0, }; |
32 | static DECLARE_COMPLETION(have_data); | |
1da177e4 | 33 | |
72d3e093 | 34 | static int rng_dev_read(struct hwrng *rng, void *buf, size_t max, bool block) |
1da177e4 | 35 | { |
72d3e093 | 36 | int ret; |
1da177e4 | 37 | |
72d3e093 CO |
38 | for (;;) { |
39 | ret = os_read_file(random_fd, buf, max); | |
40 | if (block && ret == -EAGAIN) { | |
5d33e4d7 JD |
41 | add_sigio_fd(random_fd); |
42 | ||
72d3e093 | 43 | ret = wait_for_completion_killable(&have_data); |
5d33e4d7 | 44 | |
72d3e093 CO |
45 | ignore_sigio_fd(random_fd); |
46 | deactivate_fd(random_fd, RANDOM_IRQ); | |
5d33e4d7 | 47 | |
72d3e093 CO |
48 | if (ret < 0) |
49 | break; | |
50 | } else { | |
51 | break; | |
3d88958e | 52 | } |
1da177e4 | 53 | } |
1da177e4 | 54 | |
72d3e093 CO |
55 | return ret != -EAGAIN ? ret : 0; |
56 | } | |
1da177e4 | 57 | |
5d33e4d7 JD |
58 | static irqreturn_t random_interrupt(int irq, void *data) |
59 | { | |
72d3e093 | 60 | complete(&have_data); |
5d33e4d7 JD |
61 | |
62 | return IRQ_HANDLED; | |
63 | } | |
64 | ||
1da177e4 LT |
65 | /* |
66 | * rng_init - initialize RNG module | |
67 | */ | |
68 | static int __init rng_init (void) | |
69 | { | |
70 | int err; | |
71 | ||
3d88958e JD |
72 | err = os_open_file("/dev/random", of_read(OPENFLAGS()), 0); |
73 | if (err < 0) | |
74 | goto out; | |
1da177e4 | 75 | |
3d88958e | 76 | random_fd = err; |
5d33e4d7 | 77 | err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt, |
aab94460 | 78 | 0, "random", NULL); |
36d46a59 | 79 | if (err < 0) |
1da177e4 LT |
80 | goto err_out_cleanup_hw; |
81 | ||
2fccfcc0 | 82 | sigio_broken(random_fd); |
72d3e093 CO |
83 | hwrng.name = RNG_MODULE_NAME; |
84 | hwrng.read = rng_dev_read; | |
85 | hwrng.quality = 1024; | |
5d33e4d7 | 86 | |
72d3e093 | 87 | err = hwrng_register(&hwrng); |
1da177e4 | 88 | if (err) { |
72d3e093 | 89 | pr_err(RNG_MODULE_NAME " registering failed (%d)\n", err); |
1da177e4 LT |
90 | goto err_out_cleanup_hw; |
91 | } | |
3d88958e JD |
92 | out: |
93 | return err; | |
1da177e4 | 94 | |
3d88958e | 95 | err_out_cleanup_hw: |
5d33e4d7 | 96 | os_close_file(random_fd); |
3d88958e JD |
97 | random_fd = -1; |
98 | goto out; | |
1da177e4 LT |
99 | } |
100 | ||
101 | /* | |
102 | * rng_cleanup - shutdown RNG module | |
103 | */ | |
ff6a1798 AI |
104 | |
105 | static void cleanup(void) | |
106 | { | |
107 | free_irq_by_fd(random_fd); | |
108 | os_close_file(random_fd); | |
109 | } | |
110 | ||
111 | static void __exit rng_cleanup(void) | |
1da177e4 | 112 | { |
72d3e093 | 113 | hwrng_unregister(&hwrng); |
5d33e4d7 | 114 | os_close_file(random_fd); |
1da177e4 LT |
115 | } |
116 | ||
117 | module_init (rng_init); | |
118 | module_exit (rng_cleanup); | |
ff6a1798 | 119 | __uml_exitcall(cleanup); |
567b5650 PBG |
120 | |
121 | MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver"); | |
122 | MODULE_LICENSE("GPL"); |