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Xenia-Canary/src/xenia/cpu/mmio_handler.cc

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/**
******************************************************************************
* Xenia : Xbox 360 Emulator Research Project *
******************************************************************************
* Copyright 2014 Ben Vanik. All rights reserved. *
* Released under the BSD license - see LICENSE in the root for more details. *
******************************************************************************
*/
#include "xenia/cpu/mmio_handler.h"
#include "xenia/base/assert.h"
#include "xenia/base/byte_order.h"
#include "xenia/base/exception_handler.h"
#include "xenia/base/logging.h"
#include "xenia/base/math.h"
#include "xenia/base/memory.h"
namespace xe {
namespace cpu {
MMIOHandler* MMIOHandler::global_handler_ = nullptr;
std::unique_ptr<MMIOHandler> MMIOHandler::Install(uint8_t* virtual_membase,
uint8_t* physical_membase,
uint8_t* membase_end) {
// There can be only one handler at a time.
assert_null(global_handler_);
if (global_handler_) {
return nullptr;
}
auto handler = std::unique_ptr<MMIOHandler>(
new MMIOHandler(virtual_membase, physical_membase, membase_end));
// Install the exception handler directed at the MMIOHandler.
ExceptionHandler::Install(ExceptionCallbackThunk, handler.get());
global_handler_ = handler.get();
return handler;
}
MMIOHandler::~MMIOHandler() {
ExceptionHandler::Uninstall(ExceptionCallbackThunk, this);
assert_true(global_handler_ == this);
global_handler_ = nullptr;
}
bool MMIOHandler::RegisterRange(uint32_t virtual_address, uint32_t mask,
uint32_t size, void* context,
MMIOReadCallback read_callback,
MMIOWriteCallback write_callback) {
mapped_ranges_.push_back({
virtual_address, mask, size, context, read_callback, write_callback,
});
return true;
}
MMIORange* MMIOHandler::LookupRange(uint32_t virtual_address) {
for (auto& range : mapped_ranges_) {
if ((virtual_address & range.mask) == range.address) {
return &range;
}
}
return nullptr;
}
bool MMIOHandler::CheckLoad(uint32_t virtual_address, uint32_t* out_value) {
for (const auto& range : mapped_ranges_) {
if ((virtual_address & range.mask) == range.address) {
*out_value = static_cast<uint32_t>(
range.read(nullptr, range.callback_context, virtual_address));
return true;
}
}
return false;
}
bool MMIOHandler::CheckStore(uint32_t virtual_address, uint32_t value) {
for (const auto& range : mapped_ranges_) {
if ((virtual_address & range.mask) == range.address) {
range.write(nullptr, range.callback_context, virtual_address, value);
return true;
}
}
return false;
}
uintptr_t MMIOHandler::AddPhysicalAccessWatch(uint32_t guest_address,
size_t length, WatchType type,
AccessWatchCallback callback,
void* callback_context,
void* callback_data) {
uint32_t base_address = guest_address & 0x1FFFFFFF;
// Can only protect sizes matching system page size.
// This means we need to round up, which will cause spurious access
// violations and invalidations.
// TODO(benvanik): only invalidate if actually within the region?
length = xe::round_up(length + (base_address % xe::memory::page_size()),
xe::memory::page_size());
base_address = base_address - (base_address % xe::memory::page_size());
auto lock = global_critical_region_.Acquire();
// Fire any access watches that overlap this region.
for (auto it = access_watches_.begin(); it != access_watches_.end();) {
// Case 1: 2222222|222|11111111
// Case 2: 1111111|222|22222222
// Case 3: 1111111|222|11111111 (fragmentation)
// Case 4: 2222222|222|22222222 (complete overlap)
bool hit = false;
auto entry = *it;
if (base_address < (*it)->address &&
base_address + length > (*it)->address) {
hit = true;
} else if ((*it)->address < base_address &&
(*it)->address + (*it)->length > base_address) {
hit = true;
} else if ((*it)->address < base_address &&
(*it)->address + (*it)->length > base_address + length) {
hit = true;
} else if ((*it)->address > base_address &&
(*it)->address + (*it)->length < base_address + length) {
hit = true;
}
if (hit) {
FireAccessWatch(*it);
it = access_watches_.erase(it);
delete entry;
continue;
}
++it;
}
// Add to table. The slot reservation may evict a previous watch, which
// could include our target, so we do it first.
auto entry = new AccessWatchEntry();
entry->address = base_address;
entry->length = uint32_t(length);
entry->type = type;
entry->callback = callback;
entry->callback_context = callback_context;
entry->callback_data = callback_data;
access_watches_.push_back(entry);
auto page_access = memory::PageAccess::kNoAccess;
switch (type) {
case kWatchWrite:
page_access = memory::PageAccess::kReadOnly;
break;
case kWatchReadWrite:
page_access = memory::PageAccess::kNoAccess;
break;
default:
assert_unhandled_case(type);
break;
}
// Protect the range under all address spaces
memory::Protect(physical_membase_ + entry->address, entry->length,
page_access, nullptr);
memory::Protect(virtual_membase_ + 0xA0000000 + entry->address, entry->length,
page_access, nullptr);
memory::Protect(virtual_membase_ + 0xC0000000 + entry->address, entry->length,
page_access, nullptr);
memory::Protect(virtual_membase_ + 0xE0000000 + entry->address, entry->length,
page_access, nullptr);
return reinterpret_cast<uintptr_t>(entry);
}
void MMIOHandler::FireAccessWatch(AccessWatchEntry* entry) {
ClearAccessWatch(entry);
entry->callback(entry->callback_context, entry->callback_data,
entry->address);
}
void MMIOHandler::ClearAccessWatch(AccessWatchEntry* entry) {
memory::Protect(physical_membase_ + entry->address, entry->length,
xe::memory::PageAccess::kReadWrite, nullptr);
memory::Protect(virtual_membase_ + 0xA0000000 + entry->address, entry->length,
xe::memory::PageAccess::kReadWrite, nullptr);
memory::Protect(virtual_membase_ + 0xC0000000 + entry->address, entry->length,
xe::memory::PageAccess::kReadWrite, nullptr);
memory::Protect(virtual_membase_ + 0xE0000000 + entry->address, entry->length,
xe::memory::PageAccess::kReadWrite, nullptr);
}
void MMIOHandler::CancelAccessWatch(uintptr_t watch_handle) {
auto entry = reinterpret_cast<AccessWatchEntry*>(watch_handle);
auto lock = global_critical_region_.Acquire();
// Allow access to the range again.
ClearAccessWatch(entry);
// Remove from table.
auto it = std::find(access_watches_.begin(), access_watches_.end(), entry);
assert_false(it == access_watches_.end());
if (it != access_watches_.end()) {
access_watches_.erase(it);
}
delete entry;
}
void MMIOHandler::InvalidateRange(uint32_t physical_address, size_t length) {
auto lock = global_critical_region_.Acquire();
for (auto it = access_watches_.begin(); it != access_watches_.end();) {
auto entry = *it;
if ((entry->address <= physical_address &&
entry->address + entry->length > physical_address) ||
(entry->address >= physical_address &&
entry->address < physical_address + length)) {
// This watch lies within the range. End it.
FireAccessWatch(entry);
it = access_watches_.erase(it);
delete entry;
continue;
}
++it;
}
}
bool MMIOHandler::IsRangeWatched(uint32_t physical_address, size_t length) {
auto lock = global_critical_region_.Acquire();
for (auto it = access_watches_.begin(); it != access_watches_.end(); ++it) {
auto entry = *it;
if ((entry->address <= physical_address &&
entry->address + entry->length > physical_address) ||
(entry->address >= physical_address &&
entry->address < physical_address + length)) {
// This watch lies within the range.
return true;
}
}
return false;
}
bool MMIOHandler::CheckAccessWatch(uint32_t physical_address) {
auto lock = global_critical_region_.Acquire();
bool hit = false;
for (auto it = access_watches_.begin(); it != access_watches_.end();) {
auto entry = *it;
if (entry->address <= physical_address &&
entry->address + entry->length > physical_address) {
// Hit! Remove the watch.
hit = true;
FireAccessWatch(entry);
it = access_watches_.erase(it);
delete entry;
continue;
}
++it;
}
if (!hit) {
// Rethrow access violation - range was not being watched.
return false;
}
// Range was watched, so lets eat this access violation.
return true;
}
struct DecodedMov {
size_t length;
// Inidicates this is a load (or conversely a store).
bool is_load;
// Indicates the memory must be swapped.
bool byte_swap;
// Source (for store) or target (for load) register.
// AX CX DX BX SP BP SI DI // REX.R=0
// R8 R9 R10 R11 R12 R13 R14 R15 // REX.R=1
uint32_t value_reg;
// [base + (index * scale) + displacement]
bool mem_has_base;
uint8_t mem_base_reg;
bool mem_has_index;
uint8_t mem_index_reg;
uint8_t mem_scale;
int32_t mem_displacement;
bool is_constant;
int32_t constant;
};
bool TryDecodeMov(const uint8_t* p, DecodedMov* mov) {
uint8_t i = 0; // Current byte decode index.
uint8_t rex = 0;
if ((p[i] & 0xF0) == 0x40) {
rex = p[0];
++i;
}
if (p[i] == 0x0F && p[i + 1] == 0x38 && p[i + 2] == 0xF1) {
// MOVBE m32, r32 (store)
// http://www.tptp.cc/mirrors/siyobik.info/instruction/MOVBE.html
// 44 0f 38 f1 a4 02 00 movbe DWORD PTR [rdx+rax*1+0x0],r12d
// 42 0f 38 f1 8c 22 00 movbe DWORD PTR [rdx+r12*1+0x0],ecx
// 0f 38 f1 8c 02 00 00 movbe DWORD PTR [rdx + rax * 1 + 0x0], ecx
mov->is_load = false;
mov->byte_swap = true;
i += 3;
} else if (p[i] == 0x0F && p[i + 1] == 0x38 && p[i + 2] == 0xF0) {
// MOVBE r32, m32 (load)
// http://www.tptp.cc/mirrors/siyobik.info/instruction/MOVBE.html
// 44 0f 38 f0 a4 02 00 movbe r12d,DWORD PTR [rdx+rax*1+0x0]
// 42 0f 38 f0 8c 22 00 movbe ecx,DWORD PTR [rdx+r12*1+0x0]
// 46 0f 38 f0 a4 22 00 movbe r12d,DWORD PTR [rdx+r12*1+0x0]
// 0f 38 f0 8c 02 00 00 movbe ecx,DWORD PTR [rdx+rax*1+0x0]
// 0F 38 F0 1C 02 movbe ebx,dword ptr [rdx+rax]
mov->is_load = true;
mov->byte_swap = true;
i += 3;
} else if (p[i] == 0x89) {
// MOV m32, r32 (store)
// http://www.tptp.cc/mirrors/siyobik.info/instruction/MOV.html
// 44 89 24 02 mov DWORD PTR[rdx + rax * 1], r12d
// 42 89 0c 22 mov DWORD PTR[rdx + r12 * 1], ecx
// 89 0c 02 mov DWORD PTR[rdx + rax * 1], ecx
mov->is_load = false;
mov->byte_swap = false;
++i;
} else if (p[i] == 0x8B) {
// MOV r32, m32 (load)
// http://www.tptp.cc/mirrors/siyobik.info/instruction/MOV.html
// 44 8b 24 02 mov r12d, DWORD PTR[rdx + rax * 1]
// 42 8b 0c 22 mov ecx, DWORD PTR[rdx + r12 * 1]
// 46 8b 24 22 mov r12d, DWORD PTR[rdx + r12 * 1]
// 8b 0c 02 mov ecx, DWORD PTR[rdx + rax * 1]
mov->is_load = true;
mov->byte_swap = false;
++i;
} else if (p[i] == 0xC7) {
// MOV m32, simm32
// http://www.asmpedia.org/index.php?title=MOV
// C7 04 02 02 00 00 00 mov dword ptr [rdx+rax],2
mov->is_load = false;
mov->byte_swap = false;
mov->is_constant = true;
++i;
} else {
return false;
}
uint8_t rex_b = rex & 0b0001;
uint8_t rex_x = rex & 0b0010;
uint8_t rex_r = rex & 0b0100;
uint8_t rex_w = rex & 0b1000;
// http://www.sandpile.org/x86/opc_rm.htm
// http://www.sandpile.org/x86/opc_sib.htm
uint8_t modrm = p[i++];
uint8_t mod = (modrm & 0b11000000) >> 6;
uint8_t reg = (modrm & 0b00111000) >> 3;
uint8_t rm = (modrm & 0b00000111);
mov->value_reg = reg + (rex_r ? 8 : 0);
mov->mem_has_base = false;
mov->mem_base_reg = 0;
mov->mem_has_index = false;
mov->mem_index_reg = 0;
mov->mem_scale = 1;
mov->mem_displacement = 0;
bool has_sib = false;
switch (rm) {
case 0b100: // SIB
has_sib = true;
break;
case 0b101:
if (mod == 0b00) {
// RIP-relative not supported.
return false;
}
mov->mem_has_base = true;
mov->mem_base_reg = rm + (rex_b ? 8 : 0);
break;
default:
mov->mem_has_base = true;
mov->mem_base_reg = rm + (rex_b ? 8 : 0);
break;
}
if (has_sib) {
uint8_t sib = p[i++];
mov->mem_scale = 1 << ((sib & 0b11000000) >> 8);
uint8_t sib_index = (sib & 0b00111000) >> 3;
uint8_t sib_base = (sib & 0b00000111);
switch (sib_index) {
case 0b100:
// No index.
break;
default:
mov->mem_has_index = true;
mov->mem_index_reg = sib_index + (rex_x ? 8 : 0);
break;
}
switch (sib_base) {
case 0b101:
// Alternate rbp-relative addressing not supported.
assert_zero(mod);
return false;
default:
mov->mem_has_base = true;
mov->mem_base_reg = sib_base + (rex_b ? 8 : 0);
break;
}
}
switch (mod) {
case 0b00: {
mov->mem_displacement += 0;
} break;
case 0b01: {
mov->mem_displacement += int8_t(p[i++]);
} break;
case 0b10: {
mov->mem_displacement += xe::load<int32_t>(p + i);
i += 4;
} break;
}
if (mov->is_constant) {
mov->constant = xe::load<int32_t>(p + i);
i += 4;
}
mov->length = i;
return true;
}
bool MMIOHandler::ExceptionCallbackThunk(Exception* ex, void* data) {
return reinterpret_cast<MMIOHandler*>(data)->ExceptionCallback(ex);
}
bool MMIOHandler::ExceptionCallback(Exception* ex) {
if (ex->code() != Exception::Code::kAccessViolation) {
return false;
}
if (ex->fault_address() < uint64_t(virtual_membase_) ||
ex->fault_address() > uint64_t(memory_end_)) {
// Quick kill anything outside our mapping.
return false;
}
// Access violations are pretty rare, so we can do a linear search here.
// Only check if in the virtual range, as we only support virtual ranges.
const MMIORange* range = nullptr;
if (ex->fault_address() < uint64_t(physical_membase_)) {
for (const auto& test_range : mapped_ranges_) {
if ((static_cast<uint32_t>(ex->fault_address()) & test_range.mask) ==
test_range.address) {
// Address is within the range of this mapping.
range = &test_range;
break;
}
}
}
if (!range) {
auto fault_address = reinterpret_cast<uint8_t*>(ex->fault_address());
uint32_t guest_address = 0;
if (fault_address >= virtual_membase_ &&
fault_address < physical_membase_) {
// Faulting on a virtual address.
guest_address = static_cast<uint32_t>(ex->fault_address()) & 0x1FFFFFFF;
} else {
// Faulting on a physical address.
guest_address = static_cast<uint32_t>(ex->fault_address());
}
// HACK: Recheck if the pages are still protected (race condition - another
// thread clears the writewatch we just hit)
// Do this under the lock so we don't introduce another race condition.
auto lock = global_critical_region_.Acquire();
memory::PageAccess cur_access;
size_t page_length = memory::page_size();
memory::QueryProtect((void*)fault_address, page_length, cur_access);
if (cur_access != memory::PageAccess::kReadOnly &&
cur_access != memory::PageAccess::kNoAccess) {
// Another thread has cleared this write watch. Abort.
return true;
}
// Access is not found within any range, so fail and let the caller handle
// it (likely by aborting).
return CheckAccessWatch(guest_address);
}
auto rip = ex->pc();
auto p = reinterpret_cast<const uint8_t*>(rip);
DecodedMov mov = {0};
bool decoded = TryDecodeMov(p, &mov);
if (!decoded) {
XELOGE("Unable to decode MMIO mov at %p", p);
assert_always("Unknown MMIO instruction type");
return false;
}
if (mov.is_load) {
// Load of a memory value - read from range, swap, and store in the
// register.
uint32_t value = range->read(nullptr, range->callback_context,
static_cast<uint32_t>(ex->fault_address()));
uint64_t* reg_ptr = &ex->thread_context()->int_registers[mov.value_reg];
if (!mov.byte_swap) {
// We swap only if it's not a movbe, as otherwise we are swapping twice.
value = xe::byte_swap(value);
}
*reg_ptr = value;
} else {
// Store of a register value - read register, swap, write to range.
int32_t value;
if (mov.is_constant) {
value = uint32_t(mov.constant);
} else {
uint64_t* reg_ptr = &ex->thread_context()->int_registers[mov.value_reg];
value = static_cast<uint32_t>(*reg_ptr);
if (!mov.byte_swap) {
// We swap only if it's not a movbe, as otherwise we are swapping twice.
value = xe::byte_swap(static_cast<uint32_t>(value));
}
}
range->write(nullptr, range->callback_context,
static_cast<uint32_t>(ex->fault_address()), value);
}
// Advance RIP to the next instruction so that we resume properly.
ex->set_resume_pc(rip + mov.length);
return true;
}
} // namespace cpu
} // namespace xe
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