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/*
* 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 "Emulator.h"
#include "SoftCPU.h"
#include <AK/LogStream.h>
#include <Kernel/API/Syscall.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
namespace UserspaceEmulator {
static constexpr u32 stack_location = 0x10000000;
static constexpr size_t stack_size = 64 * KB;
class SimpleRegion final : public SoftMMU::Region {
public:
SimpleRegion(u32 base, u32 size)
: Region(base, size)
{
m_data = (u8*)malloc(size);
}
~SimpleRegion()
{
free(m_data);
}
virtual u8 read8(u32 offset) override
{
ASSERT(offset < size());
return *reinterpret_cast<const u8*>(m_data + offset);
}
virtual u16 read16(u32 offset) override
{
ASSERT(offset + 1 < size());
return *reinterpret_cast<const u16*>(m_data + offset);
}
virtual u32 read32(u32 offset) override
{
ASSERT(offset + 3 < size());
return *reinterpret_cast<const u32*>(m_data + offset);
}
virtual void write8(u32 offset, u8 value) override
{
ASSERT(offset < size());
*reinterpret_cast<u8*>(m_data + offset) = value;
}
virtual void write16(u32 offset, u16 value) override
{
ASSERT(offset + 1 < size());
*reinterpret_cast<u16*>(m_data + offset) = value;
}
virtual void write32(u32 offset, u32 value) override
{
ASSERT(offset + 3 < size());
*reinterpret_cast<u32*>(m_data + offset) = value;
}
u8* data() { return m_data; }
private:
u8* m_data { nullptr };
};
Emulator::Emulator()
: m_cpu(*this)
{
setup_stack();
}
void Emulator::setup_stack()
{
auto stack_region = make<SimpleRegion>(stack_location, stack_size);
m_mmu.add_region(move(stack_region));
m_cpu.set_esp(stack_location + stack_size);
m_cpu.push32(0);
m_cpu.push32(0);
m_cpu.push32(0);
m_cpu.push32(0);
}
bool Emulator::load_elf(const ELF::Loader& elf)
{
elf.image().for_each_program_header([&](const ELF::Image::ProgramHeader& program_header) {
if (program_header.type() != PT_LOAD)
return;
auto region = make<SimpleRegion>(program_header.vaddr().get(), program_header.size_in_memory());
memcpy(region->data(), program_header.raw_data(), program_header.size_in_image());
mmu().add_region(move(region));
});
m_cpu.set_eip(elf.image().entry().get());
return true;
}
int Emulator::exec()
{
while (!m_shutdown) {
auto base_eip = m_cpu.eip();
auto insn = X86::Instruction::from_stream(m_cpu, true, true);
out() << (const void*)base_eip << " \033[33;1m" << insn.to_string(base_eip) << "\033[0m";
// FIXME: Remove this hack once it's no longer needed :^)
if (insn.mnemonic() == "RET")
break;
(m_cpu.*insn.handler())(insn);
m_cpu.dump();
}
return m_exit_status;
}
u32 Emulator::virt_syscall(u32 function, u32 arg1, u32 arg2, u32 arg3)
{
(void)arg2;
(void)arg3;
printf("Syscall: %s (%x)\n", Syscall::to_string((Syscall::Function)function), function);
switch (function) {
case SC_getuid:
return virt$getuid();
case SC_exit:
virt$exit((int)arg1);
return 0;
default:
warn() << "Unimplemented syscall!";
TODO();
}
}
uid_t Emulator::virt$getuid()
{
return getuid();
}
void Emulator::virt$exit(int status)
{
out() << "exit(" << status << "), shutting down!";
m_exit_status = status;
m_shutdown = true;
}
}
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