19fc1ee77c
PR #36996 disabled running mem_protect/stack_random test on qemu_riscv32 platform because of this test consistently failing on said platform. This test starts new threads in equal time intervals, and because of that we get repeating values after performing the modulus operation when calculating the stack pointer address. This can be solved by changing the value of the _RAND32_INC constant that is used to increase the value returned by the timer-based PRNG. This commit decreases the value of the mentioned constant from 1000000013U to 1000000003U. Fixes #37006. Signed-off-by: Filip Kokosinski <fkokosinski@antmicro.com>
78 lines
1.8 KiB
C
78 lines
1.8 KiB
C
/*
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* Copyright (c) 2013-2015 Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief Non-random number generator based on system timer
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*
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* This module provides a non-random implementation of sys_rand32_get(), which
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* is not meant to be used in a final product as a truly random number
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* generator. It was provided to allow testing on a platform that does not (yet)
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* provide a random number generator.
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*/
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#include <random/rand32.h>
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#include <drivers/timer/system_timer.h>
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#include <kernel.h>
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#include <sys/atomic.h>
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#include <string.h>
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#if defined(__GNUC__)
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/*
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* Symbols used to ensure a rapid series of calls to random number generator
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* return different values.
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*/
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static atomic_val_t _rand32_counter;
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#define _RAND32_INC 1000000003U
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/**
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*
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* @brief Get a 32 bit random number
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*
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* The non-random number generator returns values that are based off the
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* target's clock counter, which means that successive calls will return
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* different values.
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*
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* @return a 32-bit number
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*/
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uint32_t z_impl_sys_rand32_get(void)
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{
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return k_cycle_get_32() + atomic_add(&_rand32_counter, _RAND32_INC);
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}
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/**
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*
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* @brief Fill destination buffer with random numbers
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*
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* The non-random number generator returns values that are based off the
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* target's clock counter, which means that successive calls will return
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* different values.
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*
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* @param dst destination buffer to fill
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* @param outlen size of destination buffer to fill
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*
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* @return N/A
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*/
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void z_impl_sys_rand_get(void *dst, size_t outlen)
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{
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uint8_t *udst = dst;
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uint32_t blocksize;
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uint32_t ret;
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while (outlen) {
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ret = sys_rand32_get();
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blocksize = MIN(outlen, sizeof(ret));
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(void)memcpy((void *)udst, &ret, blocksize);
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udst += blocksize;
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outlen -= blocksize;
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}
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}
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#endif /* __GNUC__ */
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