84 lines
2.0 KiB
C
84 lines
2.0 KiB
C
/* Copyright (c) 2013, The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/kernel.h>
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#include <mach/scm.h>
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#include <asm/io.h>
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#include <asm/cacheflush.h>
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#define TZ_SVC_CRYPTO 10
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#define PRNG_CMD_ID 0x01
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static int use_arch_random = 1;
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struct tz_prng_data {
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uint8_t *out_buf;
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uint32_t out_buf_sz;
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} __packed;
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DEFINE_SCM_BUFFER(common_scm_buf)
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DEFINE_MUTEX(arch_random_lock);
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#define RANDOM_BUFFER_SIZE PAGE_SIZE
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char random_buffer[RANDOM_BUFFER_SIZE] __aligned(PAGE_SIZE);
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int arch_get_random_common(void *v, size_t size)
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{
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struct tz_prng_data data;
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int ret;
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u32 resp;
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if (!use_arch_random)
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return 0;
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if (size > sizeof(random_buffer))
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return 0;
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mutex_lock(&arch_random_lock);
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data.out_buf = (uint8_t *) virt_to_phys(random_buffer);
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data.out_buf_sz = size;
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ret = scm_call_noalloc(TZ_SVC_CRYPTO, PRNG_CMD_ID, &data,
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sizeof(data), &resp, sizeof(resp),
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common_scm_buf, SCM_BUFFER_SIZE(common_scm_buf));
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if (!ret) {
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dmac_inv_range(random_buffer, random_buffer +
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RANDOM_BUFFER_SIZE);
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outer_inv_range(
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(unsigned long) virt_to_phys(random_buffer),
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(unsigned long) virt_to_phys(random_buffer) +
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RANDOM_BUFFER_SIZE);
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memcpy(v, random_buffer, size);
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}
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mutex_unlock(&arch_random_lock);
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return !ret;
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}
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int arch_get_random_long(unsigned long *v)
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{
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return arch_get_random_common(v, sizeof(unsigned long));
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}
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int arch_get_random_int(unsigned int *v)
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{
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return arch_get_random_common(v, sizeof(unsigned int));
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}
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int arch_random_init(void)
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{
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use_arch_random = 0;
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return 0;
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}
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module_init(arch_random_init);
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