mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-12-04 05:20:30 +00:00
4fa6301523
CPUs which support RDRAND do not necessarily support RDSEED. This introduces a flag g_cpu_supports_rdseed which is set appropriately by CPUID. This causes Haswell CPUs in particular (and probably a lot of AMD chips) to now fail to boot with #2634, rather than an illegal instruction. It seems like the KernelRng needs either an initial reseed call or more random events added before the first call to get_good_random, but I don't feel qualified to make that kind of change.
79 lines
2.6 KiB
C++
79 lines
2.6 KiB
C++
/*
|
|
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
|
|
* Copyright (c) 2020, Peter Elliott <pelliott@ualberta.ca>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright notice, this
|
|
* list of conditions and the following disclaimer.
|
|
*
|
|
* 2. Redistributions in binary form must reproduce the above copyright notice,
|
|
* this list of conditions and the following disclaimer in the documentation
|
|
* and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
|
|
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
|
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
|
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <Kernel/Arch/i386/CPU.h>
|
|
#include <Kernel/Devices/RandomDevice.h>
|
|
#include <Kernel/Random.h>
|
|
#include <Kernel/Time/TimeManagement.h>
|
|
|
|
namespace Kernel {
|
|
|
|
static KernelRng* s_the;
|
|
|
|
KernelRng& KernelRng::the()
|
|
{
|
|
if (!s_the) {
|
|
s_the = new KernelRng;
|
|
}
|
|
return *s_the;
|
|
}
|
|
|
|
KernelRng::KernelRng()
|
|
{
|
|
if (g_cpu_supports_rdseed) {
|
|
for (size_t i = 0; i < resource().pool_count * resource().reseed_threshold; ++i) {
|
|
u32 value = 0;
|
|
asm volatile(
|
|
"1:\n"
|
|
"rdseed %0\n"
|
|
"jnc 1b\n"
|
|
: "=r"(value));
|
|
|
|
this->resource().add_random_event(value, i % 32);
|
|
}
|
|
}
|
|
}
|
|
|
|
size_t EntropySource::next_source { 0 };
|
|
|
|
void get_good_random_bytes(u8* buffer, size_t buffer_size)
|
|
{
|
|
// FIXME: What if interrupts are disabled because we're in an interrupt?
|
|
if (are_interrupts_enabled()) {
|
|
LOCKER(KernelRng::the().lock());
|
|
KernelRng::the().resource().get_random_bytes(buffer, buffer_size);
|
|
} else {
|
|
KernelRng::the().resource().get_random_bytes(buffer, buffer_size);
|
|
}
|
|
}
|
|
|
|
void get_fast_random_bytes(u8* buffer, size_t buffer_size)
|
|
{
|
|
return get_good_random_bytes(buffer, buffer_size);
|
|
}
|
|
|
|
}
|