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122 lines
2.5 KiB
122 lines
2.5 KiB
/* Copyright (C) 2005 - 2008 Jeff Dike <jdike@{linux.intel,addtoit}.com> */ |
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/* Much of this ripped from drivers/char/hw_random.c, see there for other |
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* copyright. |
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* |
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* This software may be used and distributed according to the terms |
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* of the GNU General Public License, incorporated herein by reference. |
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*/ |
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#include <linux/sched/signal.h> |
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#include <linux/module.h> |
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#include <linux/fs.h> |
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#include <linux/interrupt.h> |
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#include <linux/miscdevice.h> |
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#include <linux/hw_random.h> |
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#include <linux/delay.h> |
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#include <linux/uaccess.h> |
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#include <init.h> |
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#include <irq_kern.h> |
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#include <os.h> |
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/* |
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* core module information |
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*/ |
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#define RNG_MODULE_NAME "hw_random" |
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/* Changed at init time, in the non-modular case, and at module load |
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* time, in the module case. Presumably, the module subsystem |
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* protects against a module being loaded twice at the same time. |
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*/ |
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static int random_fd = -1; |
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static struct hwrng hwrng = { 0, }; |
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static DECLARE_COMPLETION(have_data); |
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static int rng_dev_read(struct hwrng *rng, void *buf, size_t max, bool block) |
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{ |
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int ret; |
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for (;;) { |
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ret = os_read_file(random_fd, buf, max); |
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if (block && ret == -EAGAIN) { |
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add_sigio_fd(random_fd); |
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ret = wait_for_completion_killable(&have_data); |
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ignore_sigio_fd(random_fd); |
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deactivate_fd(random_fd, RANDOM_IRQ); |
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if (ret < 0) |
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break; |
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} else { |
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break; |
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} |
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} |
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return ret != -EAGAIN ? ret : 0; |
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} |
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static irqreturn_t random_interrupt(int irq, void *data) |
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{ |
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complete(&have_data); |
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return IRQ_HANDLED; |
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} |
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/* |
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* rng_init - initialize RNG module |
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*/ |
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static int __init rng_init (void) |
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{ |
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int err; |
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err = os_open_file("/dev/random", of_read(OPENFLAGS()), 0); |
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if (err < 0) |
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goto out; |
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random_fd = err; |
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err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt, |
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0, "random", NULL); |
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if (err < 0) |
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goto err_out_cleanup_hw; |
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sigio_broken(random_fd); |
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hwrng.name = RNG_MODULE_NAME; |
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hwrng.read = rng_dev_read; |
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hwrng.quality = 1024; |
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err = hwrng_register(&hwrng); |
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if (err) { |
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pr_err(RNG_MODULE_NAME " registering failed (%d)\n", err); |
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goto err_out_cleanup_hw; |
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} |
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out: |
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return err; |
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err_out_cleanup_hw: |
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os_close_file(random_fd); |
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random_fd = -1; |
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goto out; |
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} |
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/* |
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* rng_cleanup - shutdown RNG module |
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*/ |
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static void cleanup(void) |
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{ |
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free_irq_by_fd(random_fd); |
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os_close_file(random_fd); |
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} |
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static void __exit rng_cleanup(void) |
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{ |
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hwrng_unregister(&hwrng); |
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os_close_file(random_fd); |
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} |
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module_init (rng_init); |
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module_exit (rng_cleanup); |
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__uml_exitcall(cleanup); |
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MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver"); |
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MODULE_LICENSE("GPL");
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