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UserspaceEmulator: Start sketching out a SoftMMU class :^)

This Emulator sub-object will keep track of all active memory regions
and handle memory read/write operations from the CPU.

A memory region is currently represented by a virtual Region object
that can implement arbitrary behavior by overriding read/write ops.
This commit is contained in:
Andreas Kling 2020-07-09 16:18:47 +02:00
parent 3a73fdd244
commit d5c46cf528
4 changed files with 145 additions and 0 deletions

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@ -1,5 +1,6 @@
set(SOURCES
SoftCPU.cpp
SoftMMU.cpp
Emulator.cpp
main.cpp
)

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@ -27,6 +27,7 @@
#pragma once
#include "SoftCPU.h"
#include "SoftMMU.h"
#include <AK/Types.h>
#include <LibX86/Instruction.h>
#include <sys/types.h>
@ -40,9 +41,14 @@ public:
int exec(X86::SimpleInstructionStream&, u32 base);
u32 virt_syscall(u32 function, u32 arg1, u32 arg2, u32 arg3);
SoftMMU& mmu() { return m_mmu; }
private:
SoftMMU m_mmu;
SoftCPU m_cpu;
void setup_stack();
uid_t virt$getuid();
void virt$exit(int);

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@ -0,0 +1,67 @@
/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* 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 "SoftMMU.h"
namespace UserspaceEmulator {
SoftMMU::Region* SoftMMU::find_region(u32 address)
{
for (auto& region : m_regions) {
if (region.contains(address))
return &region;
}
return nullptr;
}
void SoftMMU::add_region(NonnullOwnPtr<Region> region)
{
ASSERT(!find_region(region->base()));
// FIXME: More sanity checks pls
m_regions.append(move(region));
}
u32 SoftMMU::read32(u32 address)
{
auto* region = find_region(address);
if (!region) {
TODO();
}
return region->read32(address - region->base());
}
void SoftMMU::write32(u32 address, u32 value)
{
auto* region = find_region(address);
if (!region) {
TODO();
}
region->write32(address - region->base(), value);
}
}

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@ -0,0 +1,71 @@
/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* 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.
*/
#pragma once
#include <AK/NonnullOwnPtrVector.h>
#include <AK/Types.h>
namespace UserspaceEmulator {
class SoftMMU {
public:
class Region {
public:
virtual ~Region() { }
u32 base() const { return m_base; }
u32 size() const { return m_size; }
u32 end() const { return m_base + m_size; }
bool contains(u32 address) const { return address >= base() && address < end(); }
virtual void write32(u32 offset, u32 value) = 0;
virtual u32 read32(u32 offset) = 0;
protected:
Region(u32 base, u32 size)
: m_base(base)
, m_size(size)
{
}
private:
u32 m_base { 0 };
u32 m_size { 0 };
};
u32 read32(u32 address);
void write32(u32 address, u32 value);
Region* find_region(u32 address);
void add_region(NonnullOwnPtr<Region>);
private:
NonnullOwnPtrVector<Region> m_regions;
};
}