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Atmosphere/libraries/libvapours/include/vapours/util/util_tinymt.hpp
Michael Scire f66b41c027 exo2: Initial work on the exosphere rewrite.
exo2: Implement uncompressor stub and boot code up to Main().

exo2: implement some more init (uart/gic)

exo2: implement more of init

exo2: improve reg api, add keyslot flag setters

exo2: implement se aes decryption/enc

exo2: fix bugs in loader stub/mmu mappings

exo2: start skeletoning bootconfig/global context types

arch: fix makefile flags

exo2: implement through master key derivation

exo2: implement device master keygen

exo2: more init through start of SetupSocSecurity

exo2: implement pmc secure scratch management

se: implement sticky bit validation

libexosphere: fix building for arm32

libexo: fix makefile flags

libexo: support building for arm64/arm

sc7fw: skeleton binary

sc7fw: skeleton a little more

sc7fw: implement all non-dram functionality

exo2: fix DivideUp error

sc7fw: implement more dram code, fix reg library errors

sc7fw: complete sc7fw impl.

exo2: skeleton the rest of SetupSocSecurity

exo2: implement fiq interrupt handler

exo2: implement all exception handlers

exo2: skeleton the entire smc api, implement the svc invoker

exo2: implement rest of SetupSocSecurity

exo2: correct slave security errors

exo2: fix register definition

exo2: minor fixes
2020-06-14 22:07:45 -07:00

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/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <vapours/common.hpp>
#include <vapours/assert.hpp>
namespace ams::util {
/* Implementation of TinyMT (mersenne twister RNG). */
/* Like Nintendo, we will use the sample parameters. */
class TinyMT {
public:
static constexpr size_t NumStateWords = 4;
struct State {
u32 data[NumStateWords];
};
private:
static constexpr u32 ParamMat1 = 0x8F7011EE;
static constexpr u32 ParamMat2 = 0xFC78FF1F;
static constexpr u32 ParamTmat = 0x3793FDFF;
static constexpr u32 ParamMult = 0x6C078965;
static constexpr u32 ParamPlus = 0x0019660D;
static constexpr u32 ParamXor = 0x5D588B65;
static constexpr u32 TopBitmask = 0x7FFFFFFF;
static constexpr int MinimumInitIterations = 8;
static constexpr int NumDiscardedInitOutputs = 8;
static constexpr inline u32 XorByShifted27(u32 value) {
return value ^ (value >> 27);
}
static constexpr inline u32 XorByShifted30(u32 value) {
return value ^ (value >> 30);
}
private:
State state;
private:
/* Internal API. */
void FinalizeInitialization() {
const u32 state0 = this->state.data[0] & TopBitmask;
const u32 state1 = this->state.data[1];
const u32 state2 = this->state.data[2];
const u32 state3 = this->state.data[3];
if (state0 == 0 && state1 == 0 && state2 == 0 && state3 == 0) {
this->state.data[0] = 'T';
this->state.data[1] = 'I';
this->state.data[2] = 'N';
this->state.data[3] = 'Y';
}
for (int i = 0; i < NumDiscardedInitOutputs; i++) {
this->GenerateRandomU32();
}
}
u32 GenerateRandomU24() { return (this->GenerateRandomU32() >> 8); }
static void GenerateInitialValuePlus(TinyMT::State *state, int index, u32 value) {
u32 &state0 = state->data[(index + 0) % NumStateWords];
u32 &state1 = state->data[(index + 1) % NumStateWords];
u32 &state2 = state->data[(index + 2) % NumStateWords];
u32 &state3 = state->data[(index + 3) % NumStateWords];
const u32 x = XorByShifted27(state0 ^ state1 ^ state3) * ParamPlus;
const u32 y = x + index + value;
state0 = y;
state1 += x;
state2 += y;
}
static void GenerateInitialValueXor(TinyMT::State *state, int index) {
u32 &state0 = state->data[(index + 0) % NumStateWords];
u32 &state1 = state->data[(index + 1) % NumStateWords];
u32 &state2 = state->data[(index + 2) % NumStateWords];
u32 &state3 = state->data[(index + 3) % NumStateWords];
const u32 x = XorByShifted27(state0 + state1 + state3) * ParamXor;
const u32 y = x - index;
state0 = y;
state1 ^= x;
state2 ^= y;
}
public:
constexpr TinyMT() : state() { /* ... */ }
/* Public API. */
/* Initialization. */
void Initialize(u32 seed) {
this->state.data[0] = seed;
this->state.data[1] = ParamMat1;
this->state.data[2] = ParamMat2;
this->state.data[3] = ParamTmat;
for (int i = 1; i < MinimumInitIterations; i++) {
const u32 mixed = XorByShifted30(this->state.data[(i - 1) % NumStateWords]);
this->state.data[i % NumStateWords] ^= mixed * ParamMult + i;
}
this->FinalizeInitialization();
}
void Initialize(const u32 *seed, int seed_count) {
this->state.data[0] = 0;
this->state.data[1] = ParamMat1;
this->state.data[2] = ParamMat2;
this->state.data[3] = ParamTmat;
{
const int num_init_iterations = std::max(seed_count + 1, MinimumInitIterations) - 1;
GenerateInitialValuePlus(&this->state, 0, seed_count);
for (int i = 0; i < num_init_iterations; i++) {
GenerateInitialValuePlus(&this->state, (i + 1) % NumStateWords, (i < seed_count) ? seed[i] : 0);
}
for (int i = 0; i < static_cast<int>(NumStateWords); i++) {
GenerateInitialValueXor(&this->state, (i + 1 + num_init_iterations) % NumStateWords);
}
}
this->FinalizeInitialization();
}
/* State management. */
void GetState(TinyMT::State *out) const {
std::memcpy(out->data, this->state.data, sizeof(this->state));
}
void SetState(const TinyMT::State *state) {
std::memcpy(this->state.data, state->data, sizeof(this->state));
}
/* Random generation. */
NOINLINE void GenerateRandomBytes(void *dst, size_t size) {
const uintptr_t start = reinterpret_cast<uintptr_t>(dst);
const uintptr_t end = start + size;
const uintptr_t aligned_start = util::AlignUp(start, 4);
const uintptr_t aligned_end = util::AlignDown(end, 4);
/* Make sure we're aligned. */
if (start < aligned_start) {
const u32 rnd = this->GenerateRandomU32();
std::memcpy(dst, &rnd, aligned_start - start);
}
/* Write as many aligned u32s as we can. */
{
u32 * cur_dst = reinterpret_cast<u32 *>(aligned_start);
u32 * const end_dst = reinterpret_cast<u32 *>(aligned_end);
while (cur_dst < end_dst) {
*(cur_dst++) = this->GenerateRandomU32();
}
}
/* Handle any leftover unaligned data. */
if (aligned_end < end) {
const u32 rnd = this->GenerateRandomU32();
std::memcpy(reinterpret_cast<void *>(aligned_end), &rnd, end - aligned_end);
}
}
NOINLINE u32 GenerateRandomU32() {
/* Advance state. */
const u32 x0 = (this->state.data[0] & TopBitmask) ^ this->state.data[1] ^ this->state.data[2];
const u32 y0 = this->state.data[3];
const u32 x1 = x0 ^ (x0 << 1);
const u32 y1 = y0 ^ (y0 >> 1) ^ x1;
const u32 state0 = this->state.data[1];
u32 state1 = this->state.data[2];
u32 state2 = x1 ^ (y1 << 10);
const u32 state3 = y1;
if ((y1 & 1) != 0) {
state1 ^= ParamMat1;
state2 ^= ParamMat2;
}
this->state.data[0] = state0;
this->state.data[1] = state1;
this->state.data[2] = state2;
this->state.data[3] = state3;
/* Temper. */
const u32 t1 = state0 + (state2 >> 8);
u32 t0 = state3 ^ t1;
if ((t1 & 1) != 0) {
t0 ^= ParamTmat;
}
return t0;
}
inline u64 GenerateRandomU64() {
const u32 lo = this->GenerateRandomU32();
const u32 hi = this->GenerateRandomU32();
return (static_cast<u64>(hi) << 32) | static_cast<u64>(lo);
}
inline float GenerateRandomF32() {
/* Floats have 24 bits of mantissa. */
constexpr int MantissaBits = 24;
return GenerateRandomU24() * (1.0f / (1ul << MantissaBits));
}
inline double GenerateRandomF64() {
/* Doubles have 53 bits of mantissa. */
/* The smart way to generate 53 bits of random would be to use 32 bits */
/* from the first rnd32() call, and then 21 from the second. */
/* Nintendo does not. They use (32 - 5) = 27 bits from the first rnd32() */
/* call, and (32 - 6) bits from the second. We'll do what they do, but */
/* There's not a clear reason why. */
constexpr int MantissaBits = 53;
constexpr int Shift1st = (64 - MantissaBits) / 2;
constexpr int Shift2nd = (64 - MantissaBits) - Shift1st;
const u32 first = (this->GenerateRandomU32() >> Shift1st);
const u32 second = (this->GenerateRandomU32() >> Shift2nd);
return (1.0 * first * (static_cast<u64>(1) << (32 - Shift2nd)) + second) * (1.0 / (static_cast<u64>(1) << MantissaBits));
}
};
}