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DolphinQt: Properly lock CPU before accessing emulated memory

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This fixes a problem I was having where using frame advance with the
debugger open would frequently cause panic alerts about invalid addresses
due to the CPU thread changing MSR.DR while the host thread was trying
to access memory.

To aid in tracking down all the places where we weren't properly locking
the CPU, I've created a new type (in Core.h) that you have to pass as a
reference or pointer to functions that require running as the CPU thread.
This commit is contained in:
JosJuice
2023-02-12 11:07:11 +01:00
parent efed037c4a
commit 7cecb28bdf
79 changed files with 1796 additions and 1184 deletions
Download Patch File Download Diff File Expand all files Collapse all files

50
Source/Core/Core/PatchEngine.cpp
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@ -28,6 +28,7 @@
#include "Core/CheatCodes.h"
#include "Core/Config/SessionSettings.h"
#include "Core/ConfigManager.h"
#include "Core/Core.h"
#include "Core/Debugger/PPCDebugInterface.h"
#include "Core/GeckoCode.h"
#include "Core/GeckoCodeConfig.h"
@ -230,7 +231,7 @@ void LoadPatches()
LoadSpeedhacks("Speedhacks", merged);
}
static void ApplyPatches(const std::vector<Patch>& patches)
static void ApplyPatches(const Core::CPUThreadGuard& guard, const std::vector<Patch>& patches)
{
for (const Patch& patch : patches)
{
@ -244,16 +245,17 @@ static void ApplyPatches(const std::vector<Patch>& patches)
switch (entry.type)
{
case PatchType::Patch8Bit:
if (!entry.conditional || PowerPC::HostRead_U8(addr) == static_cast<u8>(comparand))
PowerPC::HostWrite_U8(static_cast<u8>(value), addr);
if (!entry.conditional || PowerPC::HostRead_U8(guard, addr) == static_cast<u8>(comparand))
PowerPC::HostWrite_U8(guard, static_cast<u8>(value), addr);
break;
case PatchType::Patch16Bit:
if (!entry.conditional || PowerPC::HostRead_U16(addr) == static_cast<u16>(comparand))
PowerPC::HostWrite_U16(static_cast<u16>(value), addr);
if (!entry.conditional ||
PowerPC::HostRead_U16(guard, addr) == static_cast<u16>(comparand))
PowerPC::HostWrite_U16(guard, static_cast<u16>(value), addr);
break;
case PatchType::Patch32Bit:
if (!entry.conditional || PowerPC::HostRead_U32(addr) == comparand)
PowerPC::HostWrite_U32(value, addr);
if (!entry.conditional || PowerPC::HostRead_U32(guard, addr) == comparand)
PowerPC::HostWrite_U32(guard, value, addr);
break;
default:
// unknown patchtype
@ -264,19 +266,20 @@ static void ApplyPatches(const std::vector<Patch>& patches)
}
}
static void ApplyMemoryPatches(std::span<const std::size_t> memory_patch_indices)
static void ApplyMemoryPatches(const Core::CPUThreadGuard& guard,
std::span<const std::size_t> memory_patch_indices)
{
std::lock_guard lock(s_on_frame_memory_mutex);
for (std::size_t index : memory_patch_indices)
{
PowerPC::debug_interface.ApplyExistingPatch(index);
PowerPC::debug_interface.ApplyExistingPatch(guard, index);
}
}
// Requires MSR.DR, MSR.IR
// There's no perfect way to do this, it's just a heuristic.
// We require at least 2 stack frames, if the stack is shallower than that then it won't work.
static bool IsStackSane()
static bool IsStackValid(const Core::CPUThreadGuard& guard)
{
auto& system = Core::System::GetInstance();
auto& ppc_state = system.GetPPCState();
@ -285,19 +288,19 @@ static bool IsStackSane()
// Check the stack pointer
u32 SP = ppc_state.gpr[1];
if (!PowerPC::HostIsRAMAddress(SP))
if (!PowerPC::HostIsRAMAddress(guard, SP))
return false;
// Read the frame pointer from the stack (find 2nd frame from top), assert that it makes sense
u32 next_SP = PowerPC::HostRead_U32(SP);
if (next_SP <= SP || !PowerPC::HostIsRAMAddress(next_SP) ||
!PowerPC::HostIsRAMAddress(next_SP + 4))
u32 next_SP = PowerPC::HostRead_U32(guard, SP);
if (next_SP <= SP || !PowerPC::HostIsRAMAddress(guard, next_SP) ||
!PowerPC::HostIsRAMAddress(guard, next_SP + 4))
return false;
// Check the link register makes sense (that it points to a valid IBAT address)
const u32 address = PowerPC::HostRead_U32(next_SP + 4);
return PowerPC::HostIsInstructionRAMAddress(address) &&
0 != PowerPC::HostRead_Instruction(address);
const u32 address = PowerPC::HostRead_U32(guard, next_SP + 4);
return PowerPC::HostIsInstructionRAMAddress(guard, address) &&
0 != PowerPC::HostRead_Instruction(guard, address);
}
void AddMemoryPatch(std::size_t index)
@ -318,11 +321,14 @@ bool ApplyFramePatches()
auto& system = Core::System::GetInstance();
auto& ppc_state = system.GetPPCState();
ASSERT(Core::IsCPUThread());
Core::CPUThreadGuard guard;
// Because we're using the VI Interrupt to time this instead of patching the game with a
// callback hook we can end up catching the game in an exception vector.
// We deal with this by returning false so that SystemTimers will reschedule us in a few cycles
// where we can try again after the CPU hopefully returns back to the normal instruction flow.
if (!ppc_state.msr.DR || !ppc_state.msr.IR || !IsStackSane())
if (!ppc_state.msr.DR || !ppc_state.msr.IR || !IsStackValid(guard))
{
DEBUG_LOG_FMT(ACTIONREPLAY,
"Need to retry later. CPU configuration is currently incorrect. PC = {:#010x}, "
@ -331,12 +337,12 @@ bool ApplyFramePatches()
return false;
}
ApplyPatches(s_on_frame);
ApplyMemoryPatches(s_on_frame_memory);
ApplyPatches(guard, s_on_frame);
ApplyMemoryPatches(guard, s_on_frame_memory);
// Run the Gecko code handler
Gecko::RunCodeHandler();
ActionReplay::RunAllActive();
Gecko::RunCodeHandler(guard);
ActionReplay::RunAllActive(guard);
return true;
}