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random: remove rand32_timestamp.c

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This is a copy of rand32_timer.c that uses
z_do_read_cpu_timestamp32() instead of k_cycle_get_32(),
with some logic to ensure different values when called in
rapid succession missing.

Like the other driver, its reported values are not random,
it's a testing generator only.

This appears to have no advantages over rand32_timer.c,
just remove it. In QEMU emulation, the reported TSC values
tend to have the lowest five bits zeroed.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2020-02-19 10:12:39 -08:00 • committed by Anas Nashif
commit 81cfb08f52
4 changed files with 0 additions and 82 deletions
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4
doc/reference/random/index.rst
View file

@ -47,10 +47,6 @@ An override of the default value can be specified in the SOC or board
The random number generators available include:
:option:`CONFIG_X86_TSC_RANDOM_GENERATOR`
enables number generator based on timestamp counter of x86 boards,
obtained with rdtsc instruction.
:option:`CONFIG_TIMER_RANDOM_GENERATOR`
enables number generator based on system timer clock. This number
generator is not random and used for testing only.

2
subsys/random/CMakeLists.txt
View file

@ -2,13 +2,11 @@
if (CONFIG_ENTROPY_DEVICE_RANDOM_GENERATOR OR
CONFIG_TIMER_RANDOM_GENERATOR OR
CONFIG_X86_TSC_RANDOM_GENERATOR OR
CONFIG_XOROSHIRO_RANDOM_GENERATOR)
zephyr_library()
endif()
zephyr_library_sources_ifdef(CONFIG_TIMER_RANDOM_GENERATOR rand32_timer.c)
zephyr_library_sources_ifdef(CONFIG_X86_TSC_RANDOM_GENERATOR rand32_timestamp.c)
zephyr_library_sources_ifdef(CONFIG_XOROSHIRO_RANDOM_GENERATOR rand32_xoroshiro128.c)
zephyr_library_sources_ifdef(CONFIG_CTR_DRBG_CSPRNG_GENERATOR rand32_ctr_drbg.c)

7
subsys/random/Kconfig
View file

@ -26,13 +26,6 @@ choice RNG_GENERATOR_CHOICE
to support random request then select that. Otherwise, select the
XOROSHIRO algorithm
config X86_TSC_RANDOM_GENERATOR
bool "x86 timestamp counter based number generator"
depends on TEST_RANDOM_GENERATOR && X86
help
This options enables number generator based on timestamp counter
of x86 boards, obtained with rdtsc instruction.
config TIMER_RANDOM_GENERATOR
bool "System timer clock based number generator"
depends on TEST_RANDOM_GENERATOR

69
subsys/random/rand32_timestamp.c
View file

@ -1,69 +0,0 @@
/*
* Copyright (c) 2013-2014 Wind River Systems, Inc.
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief Non-random number generator based on x86 CPU timestamp
*
* This module provides a non-random implementation of sys_rand32_get(), which
* is not meant to be used in a final product as a truly random number
* generator. It was provided to allow testing on a platform that does not (yet)
* provide a random number generator.
*/
#include <kernel.h>
#include <arch/cpu.h>
#include <random/rand32.h>
#include <string.h>
/**
*
* @brief Get a 32 bit random number
*
* The non-random number generator returns values that are based off the
* CPU's timestamp counter, which means that successive calls will normally
* display ever-increasing values.
*
* @return a 32-bit number
*/
u32_t sys_rand32_get(void)
{
return z_do_read_cpu_timestamp32();
}
/**
*
* @brief Fill destination buffer with random numbers
*
* The non-random number generator returns values that are based off the
* target's clock counter, which means that successive calls will return
* different values.
*
* @param dst destination buffer to fill
* @param outlen size of destination buffer to fill
*
* @return N/A
*/
void sys_rand_get(void *dst, size_t outlen)
{
u32_t len = 0;
u32_t blocksize = 4;
u32_t ret;
u32_t *udst = (u32_t *)dst;
while (len < outlen) {
ret = sys_rand32_get();
if ((outlen-len) < sizeof(ret)) {
blocksize = len;
(void)memcpy(udst, &ret, blocksize);
} else {
(*udst++) = ret;
}
len += blocksize;
}
}