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Merge pull request #11399 from JosJuice/jit-one-stack 

Jit: Don't use a second stack
This commit is contained in:
JosJuice 2023-03-03 22:27:16 +01:00 committed by GitHub
parent a93b5a4a35 b6256a57ef
commit 95ce41ac56
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
12 changed files with 248 additions and 258 deletions
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26
Source/Android/jni/MainAndroid.cpp
View File

@ -195,26 +195,18 @@ std::unique_ptr<GBAHostInterface> Host_CreateGBAHost(std::weak_ptr<HW::GBA::Core
static bool MsgAlert(const char* caption, const char* text, bool yes_no, Common::MsgType style)
{
// If a panic alert happens very early in the execution of a game, we can crash here with
// the error "JNI NewString called with pending exception java.lang.StackOverflowError".
// As a workaround, let's put the call on a new thread with a brand new stack.
JNIEnv* env = IDCache::GetEnvForThread();
jboolean result;
jstring j_caption = ToJString(env, caption);
jstring j_text = ToJString(env, text);
std::thread([&] {
JNIEnv* env = IDCache::GetEnvForThread();
// Execute the Java method.
jboolean result = env->CallStaticBooleanMethod(
IDCache::GetNativeLibraryClass(), IDCache::GetDisplayAlertMsg(), j_caption, j_text, yes_no,
style == Common::MsgType::Warning, s_need_nonblocking_alert_msg);
jstring j_caption = ToJString(env, caption);
jstring j_text = ToJString(env, text);
// Execute the Java method.
result = env->CallStaticBooleanMethod(
IDCache::GetNativeLibraryClass(), IDCache::GetDisplayAlertMsg(), j_caption, j_text, yes_no,
style == Common::MsgType::Warning, s_need_nonblocking_alert_msg);
env->DeleteLocalRef(j_caption);
env->DeleteLocalRef(j_text);
}).join();
env->DeleteLocalRef(j_caption);
env->DeleteLocalRef(j_text);
return result != JNI_FALSE;
}

36
Source/Core/Common/Thread.cpp
View File

@ -7,6 +7,7 @@
#include <Windows.h>
#include <processthreadsapi.h>
#else
#include <pthread.h>
#include <unistd.h>
#endif
@ -185,6 +186,41 @@ void SetCurrentThreadName(const char* name)
#endif
}
std::tuple<void*, size_t> GetCurrentThreadStack()
{
void* stack_addr;
size_t stack_size;
pthread_t self = pthread_self();
#ifdef __APPLE__
stack_size = pthread_get_stacksize_np(self);
stack_addr = reinterpret_cast<u8*>(pthread_get_stackaddr_np(self)) - stack_size;
#elif defined __OpenBSD__
stack_t stack;
pthread_stackseg_np(self, &stack);
stack_addr = reinterpret_cast<u8*>(stack->ss_sp) - stack->ss_size;
stack_size = stack->ss_size;
#else
pthread_attr_t attr;
#ifdef __FreeBSD__
pthread_attr_init(&attr);
pthread_attr_get_np(self, &attr);
#else
// Linux and NetBSD
pthread_getattr_np(self, &attr);
#endif
pthread_attr_getstack(&attr, &stack_addr, &stack_size);
pthread_attr_destroy(&attr);
#endif
return std::make_tuple(stack_addr, stack_size);
}
#endif
} // namespace Common

9
Source/Core/Common/Thread.h
View File

@ -5,6 +5,10 @@
#include <thread>
#ifndef _WIN32
#include <tuple>
#endif
// Don't include Common.h here as it will break LogManager
#include "Common/CommonTypes.h"
@ -35,4 +39,9 @@ inline void YieldCPU()
void SetCurrentThreadName(const char* name);
#ifndef _WIN32
// Returns the lowest address of the stack and the size of the stack
std::tuple<void*, size_t> GetCurrentThreadStack();
#endif
} // namespace Common

128
Source/Core/Core/PowerPC/Jit64/Jit.cpp
View File

@ -19,7 +19,6 @@
#include "Common/GekkoDisassembler.h"
#include "Common/IOFile.h"
#include "Common/Logging/Log.h"
#include "Common/MemoryUtil.h"
#include "Common/PerformanceCounter.h"
#include "Common/StringUtil.h"
#include "Common/Swap.h"
@ -117,108 +116,21 @@ using namespace PowerPC;
and such, but it's currently limited to integer ops only. This can definitely be made better.
*/
// The BLR optimization is nice, but it means that JITted code can overflow the
// native stack by repeatedly running BL. (The chance of this happening in any
// retail game is close to 0, but correctness is correctness...) Also, the
// overflow might not happen directly in the JITted code but in a C++ function
// called from it, so we can't just adjust RSP in the case of a fault.
// Instead, we have to have extra stack space preallocated under the fault
// point which allows the code to continue, after wiping the JIT cache so we
// can reset things at a safe point. Once this condition trips, the
// optimization is permanently disabled, under the assumption this will never
// happen in practice.
// On Unix, we just mark an appropriate region of the stack as PROT_NONE and
// handle it the same way as fastmem faults. It's safe to take a fault with a
// bad RSP, because on Linux we can use sigaltstack and on OS X we're already
// on a separate thread.
// Windows is... under-documented.
// It already puts guard pages so it can automatically grow the stack and it
// doesn't look like there is a way to hook into a guard page fault and implement
// our own logic.
// But when windows reaches the last guard page, it raises a "Stack Overflow"
// exception which we can hook into, however by default it leaves you with less
// than 4kb of stack. So we use SetThreadStackGuarantee to trigger the Stack
// Overflow early while we still have 512kb of stack remaining.
// After resetting the stack to the top, we call _resetstkoflw() to restore
// the guard page at the 512kb mark.
enum
{
STACK_SIZE = 2 * 1024 * 1024,
SAFE_STACK_SIZE = 512 * 1024,
GUARD_SIZE = 0x10000, // two guards - bottom (permanent) and middle (see above)
GUARD_OFFSET = STACK_SIZE - SAFE_STACK_SIZE - GUARD_SIZE,
};
Jit64::Jit64() : QuantizedMemoryRoutines(*this)
{
}
Jit64::~Jit64() = default;
void Jit64::AllocStack()
{
#ifndef _WIN32
m_stack = static_cast<u8*>(Common::AllocateMemoryPages(STACK_SIZE));
Common::ReadProtectMemory(m_stack, GUARD_SIZE);
Common::ReadProtectMemory(m_stack + GUARD_OFFSET, GUARD_SIZE);
#else
// For windows we just keep using the system stack and reserve a large amount of memory at the end
// of the stack.
ULONG reserveSize = SAFE_STACK_SIZE;
SetThreadStackGuarantee(&reserveSize);
#endif
}
void Jit64::FreeStack()
{
#ifndef _WIN32
if (m_stack)
{
Common::FreeMemoryPages(m_stack, STACK_SIZE);
m_stack = nullptr;
}
#endif
}
bool Jit64::HandleStackFault()
{
// It's possible the stack fault might have been caused by something other than
// the BLR optimization. If the fault was triggered from another thread, or
// when BLR optimization isn't enabled then there is nothing we can do about the fault.
// Return false so the regular stack overflow handler can trigger (which crashes)
if (!m_enable_blr_optimization || !Core::IsCPUThread())
return false;
WARN_LOG_FMT(POWERPC, "BLR cache disabled due to excessive BL in the emulated program.");
m_enable_blr_optimization = false;
#ifndef _WIN32
// Windows does this automatically.
Common::UnWriteProtectMemory(m_stack + GUARD_OFFSET, GUARD_SIZE);
#endif
// We're going to need to clear the whole cache to get rid of the bad
// CALLs, but we can't yet. Fake the downcount so we're forced to the
// dispatcher (no block linking), and clear the cache so we're sent to
// Jit. In the case of Windows, we will also need to call _resetstkoflw()
// to reset the guard page.
// Yeah, it's kind of gross.
GetBlockCache()->InvalidateICache(0, 0xffffffff, true);
Core::System::GetInstance().GetCoreTiming().ForceExceptionCheck(0);
m_cleanup_after_stackfault = true;
return true;
}
bool Jit64::HandleFault(uintptr_t access_address, SContext* ctx)
{
uintptr_t stack = (uintptr_t)m_stack;
uintptr_t diff = access_address - stack;
const uintptr_t stack_guard = reinterpret_cast<uintptr_t>(m_stack_guard);
// In the trap region?
if (m_enable_blr_optimization && diff >= GUARD_OFFSET && diff < GUARD_OFFSET + GUARD_SIZE)
if (m_enable_blr_optimization && access_address >= stack_guard &&
access_address < stack_guard + GUARD_SIZE)
{
return HandleStackFault();
}
// This generates some fairly heavy trampolines, but it doesn't really hurt.
// Only instructions that access I/O will get these, and there won't be that
@ -365,17 +277,10 @@ void Jit64::Init()
m_const_pool.Init(AllocChildCodeSpace(constpool_size), constpool_size);
ResetCodePtr();
// BLR optimization has the same consequences as block linking, as well as
// depending on the fault handler to be safe in the event of excessive BL.
m_enable_blr_optimization = jo.enableBlocklink && m_fastmem_enabled && !m_enable_debugging;
m_cleanup_after_stackfault = false;
m_stack = nullptr;
if (m_enable_blr_optimization)
AllocStack();
m_stack_guard = nullptr;
blocks.Init();
asm_routines.Init(m_stack ? (m_stack + STACK_SIZE) : nullptr);
asm_routines.Init();
// important: do this *after* generating the global asm routines, because we can't use farcode in
// them.
@ -415,7 +320,6 @@ void Jit64::ResetFreeMemoryRanges()
void Jit64::Shutdown()
{
FreeStack();
FreeCodeSpace();
auto& system = Core::System::GetInstance();
@ -735,14 +639,22 @@ void Jit64::WriteExternalExceptionExit()
void Jit64::Run()
{
ProtectStack();
CompiledCode pExecAddr = (CompiledCode)asm_routines.enter_code;
pExecAddr();
UnprotectStack();
}
void Jit64::SingleStep()
{
ProtectStack();
CompiledCode pExecAddr = (CompiledCode)asm_routines.enter_code;
pExecAddr();
UnprotectStack();
}
void Jit64::Trace()
@ -779,15 +691,7 @@ void Jit64::Jit(u32 em_address)
void Jit64::Jit(u32 em_address, bool clear_cache_and_retry_on_failure)
{
if (m_cleanup_after_stackfault)
{
ClearCache();
m_cleanup_after_stackfault = false;
#ifdef _WIN32
// The stack is in an invalid state with no guard page, reset it.
_resetstkoflw();
#endif
}
CleanUpAfterStackFault();
if (trampolines.IsAlmostFull() || SConfig::GetInstance().bJITNoBlockCache)
{

8
Source/Core/Core/PowerPC/Jit64/Jit.h
View File

@ -50,7 +50,6 @@ public:
void Shutdown() override;
bool HandleFault(uintptr_t access_address, SContext* ctx) override;
bool HandleStackFault() override;
bool BackPatch(SContext* ctx);
void EnableOptimization();
@ -255,9 +254,6 @@ private:
bool HandleFunctionHooking(u32 address);
void AllocStack();
void FreeStack();
void ResetFreeMemoryRanges();
JitBlockCache blocks{*this};
@ -268,10 +264,6 @@ private:
Jit64AsmRoutineManager asm_routines{*this};
bool m_enable_blr_optimization = false;
bool m_cleanup_after_stackfault = false;
u8* m_stack = nullptr;
HyoutaUtilities::RangeSizeSet<u8*> m_free_ranges_near;
HyoutaUtilities::RangeSizeSet<u8*> m_free_ranges_far;
};

28
Source/Core/Core/PowerPC/Jit64/JitAsm.cpp
View File

@ -24,10 +24,9 @@ Jit64AsmRoutineManager::Jit64AsmRoutineManager(Jit64& jit) : CommonAsmRoutines(j
{
}
void Jit64AsmRoutineManager::Init(u8* stack_top)
void Jit64AsmRoutineManager::Init()
{
m_const_pool.Init(AllocChildCodeSpace(4096), 4096);
m_stack_top = stack_top;
Generate();
WriteProtect();
}
@ -50,17 +49,8 @@ void Jit64AsmRoutineManager::Generate()
// MOV(64, R(RMEM), Imm64((u64)Memory::physical_base));
MOV(64, R(RPPCSTATE), Imm64((u64)&PowerPC::ppcState + 0x80));
if (m_stack_top)
{
// Pivot the stack to our custom one.
MOV(64, R(RSCRATCH), R(RSP));
MOV(64, R(RSP), ImmPtr(m_stack_top - 0x20));
MOV(64, MDisp(RSP, 0x18), R(RSCRATCH));
}
else
{
MOV(64, PPCSTATE(stored_stack_pointer), R(RSP));
}
MOV(64, PPCSTATE(stored_stack_pointer), R(RSP));
// something that can't pass the BLR test
MOV(64, MDisp(RSP, 8), Imm32((u32)-1));
@ -209,12 +199,9 @@ void Jit64AsmRoutineManager::Generate()
if (enable_debugging)
SetJumpTarget(dbg_exit);
// Reset the stack pointer, since the BLR optimization may have pushed things onto the stack
// without popping them.
ResetStack(*this);
if (m_stack_top)
{
ADD(64, R(RSP), Imm8(0x18));
POP(RSP);
}
ABI_PopRegistersAndAdjustStack(ABI_ALL_CALLEE_SAVED, 8, 16);
RET();
@ -226,10 +213,7 @@ void Jit64AsmRoutineManager::Generate()
void Jit64AsmRoutineManager::ResetStack(X64CodeBlock& emitter)
{
if (m_stack_top)
emitter.MOV(64, R(RSP), Imm64((u64)m_stack_top - 0x20));
else
emitter.MOV(64, R(RSP), PPCSTATE(stored_stack_pointer));
emitter.MOV(64, R(RSP), PPCSTATE(stored_stack_pointer));
}
void Jit64AsmRoutineManager::GenerateCommon()

3
Source/Core/Core/PowerPC/Jit64/JitAsm.h
View File

@ -36,7 +36,7 @@ public:
explicit Jit64AsmRoutineManager(Jit64& jit);
void Init(u8* stack_top);
void Init();
void ResetStack(Gen::X64CodeBlock& emitter);
@ -44,6 +44,5 @@ private:
void Generate();
void GenerateCommon();
u8* m_stack_top = nullptr;
JitBase& m_jit;
};

84
Source/Core/Core/PowerPC/JitArm64/Jit.cpp
View File

@ -38,11 +38,6 @@ constexpr size_t CODE_SIZE = 1024 * 1024 * 32;
constexpr size_t FARCODE_SIZE = 1024 * 1024 * 64;
constexpr size_t FARCODE_SIZE_MMU = 1024 * 1024 * 64;
constexpr size_t STACK_SIZE = 2 * 1024 * 1024;
constexpr size_t SAFE_STACK_SIZE = 512 * 1024;
constexpr size_t GUARD_SIZE = 64 * 1024; // two guards - bottom (permanent) and middle (see above)
constexpr size_t GUARD_OFFSET = STACK_SIZE - SAFE_STACK_SIZE - GUARD_SIZE;
JitArm64::JitArm64() : m_float_emit(this)
{
}
@ -71,10 +66,6 @@ void JitArm64::Init()
code_block.m_gpa = &js.gpa;
code_block.m_fpa = &js.fpa;
m_enable_blr_optimization = jo.enableBlocklink && m_fastmem_enabled && !m_enable_debugging;
m_cleanup_after_stackfault = false;
AllocStack();
GenerateAsm();
ResetFreeMemoryRanges();
@ -117,9 +108,8 @@ bool JitArm64::HandleFault(uintptr_t access_address, SContext* ctx)
bool success = false;
// Handle BLR stack faults, may happen in C++ code.
uintptr_t stack = (uintptr_t)m_stack_base;
uintptr_t diff = access_address - stack;
if (diff >= GUARD_OFFSET && diff < GUARD_OFFSET + GUARD_SIZE)
const uintptr_t stack_guard = reinterpret_cast<uintptr_t>(m_stack_guard);
if (access_address >= stack_guard && access_address < stack_guard + GUARD_SIZE)
success = HandleStackFault();
// If the fault is in JIT code space, look for fastmem areas.
@ -156,23 +146,6 @@ bool JitArm64::HandleFault(uintptr_t access_address, SContext* ctx)
return success;
}
bool JitArm64::HandleStackFault()
{
if (!m_enable_blr_optimization)
return false;
ERROR_LOG_FMT(POWERPC, "BLR cache disabled due to excessive BL in the emulated program.");
m_enable_blr_optimization = false;
#ifndef _WIN32
Common::UnWriteProtectMemory(m_stack_base + GUARD_OFFSET, GUARD_SIZE);
#endif
GetBlockCache()->InvalidateICache(0, 0xffffffff, true);
Core::System::GetInstance().GetCoreTiming().ForceExceptionCheck(0);
m_cleanup_after_stackfault = true;
return true;
}
void JitArm64::ClearCache()
{
m_fault_to_handler.clear();
@ -205,7 +178,6 @@ void JitArm64::Shutdown()
memory.ShutdownFastmemArena();
FreeCodeSpace();
blocks.Shutdown();
FreeStack();
}
void JitArm64::FallBackToInterpreter(UGeckoInstruction inst)
@ -337,40 +309,6 @@ void JitArm64::ResetStack()
ADD(ARM64Reg::SP, ARM64Reg::X0, 0);
}
void JitArm64::AllocStack()
{
if (!m_enable_blr_optimization)
return;
#ifndef _WIN32
m_stack_base = static_cast<u8*>(Common::AllocateMemoryPages(STACK_SIZE));
if (!m_stack_base)
{
m_enable_blr_optimization = false;
return;
}
m_stack_pointer = m_stack_base + STACK_SIZE;
Common::ReadProtectMemory(m_stack_base, GUARD_SIZE);
Common::ReadProtectMemory(m_stack_base + GUARD_OFFSET, GUARD_SIZE);
#else
// For windows we just keep using the system stack and reserve a large amount of memory at the end
// of the stack.
ULONG reserveSize = SAFE_STACK_SIZE;
SetThreadStackGuarantee(&reserveSize);
#endif
}
void JitArm64::FreeStack()
{
#ifndef _WIN32
if (m_stack_base)
Common::FreeMemoryPages(m_stack_base, STACK_SIZE);
m_stack_base = nullptr;
m_stack_pointer = nullptr;
#endif
}
void JitArm64::IntializeSpeculativeConstants()
{
// If the block depends on an input register which looks like a gather pipe or MMIO related
@ -696,14 +634,22 @@ void JitArm64::EndTimeProfile(JitBlock* b)
void JitArm64::Run()
{
ProtectStack();
CompiledCode pExecAddr = (CompiledCode)enter_code;
pExecAddr();
UnprotectStack();
}
void JitArm64::SingleStep()
{
ProtectStack();
CompiledCode pExecAddr = (CompiledCode)enter_code;
pExecAddr();
UnprotectStack();
}
void JitArm64::Trace()
@ -740,15 +686,7 @@ void JitArm64::Jit(u32 em_address)
void JitArm64::Jit(u32 em_address, bool clear_cache_and_retry_on_failure)
{
if (m_cleanup_after_stackfault)
{
ClearCache();
m_cleanup_after_stackfault = false;
#ifdef _WIN32
// The stack is in an invalid state with no guard page, reset it.
_resetstkoflw();
#endif
}
CleanUpAfterStackFault();
if (SConfig::GetInstance().bJITNoBlockCache)
ClearCache();

9
Source/Core/Core/PowerPC/JitArm64/Jit.h
View File

@ -32,7 +32,6 @@ public:
bool IsInCodeSpace(const u8* ptr) const { return IsInSpace(ptr); }
bool HandleFault(uintptr_t access_address, SContext* ctx) override;
void DoBacktrace(uintptr_t access_address, SContext* ctx);
bool HandleStackFault() override;
bool HandleFastmemFault(SContext* ctx);
void ClearCache() override;
@ -288,8 +287,6 @@ protected:
void DoDownCount();
void Cleanup();
void ResetStack();
void AllocStack();
void FreeStack();
void ResetFreeMemoryRanges();
@ -363,12 +360,6 @@ protected:
u8* m_near_code_end = nullptr;
bool m_near_code_write_failed = false;
bool m_enable_blr_optimization = false;
bool m_cleanup_after_stackfault = false;
u8* m_stack_base = nullptr;
u8* m_stack_pointer = nullptr;
u8* m_saved_stack_pointer = nullptr;
HyoutaUtilities::RangeSizeSet<u8*> m_free_ranges_near;
HyoutaUtilities::RangeSizeSet<u8*> m_free_ranges_far;
};

19
Source/Core/Core/PowerPC/JitArm64/JitAsm.cpp
View File

@ -45,23 +45,14 @@ void JitArm64::GenerateAsm()
MOVP2R(PPC_REG, &PowerPC::ppcState);
// Swap the stack pointer, so we have proper guard pages.
// Store the stack pointer, so we can reset it if the BLR optimization fails.
ADD(ARM64Reg::X0, ARM64Reg::SP, 0);
STR(IndexType::Unsigned, ARM64Reg::X0, ARM64Reg::X1,
MOVPage2R(ARM64Reg::X1, &m_saved_stack_pointer));
LDR(IndexType::Unsigned, ARM64Reg::X0, ARM64Reg::X1, MOVPage2R(ARM64Reg::X1, &m_stack_pointer));
FixupBranch no_fake_stack = CBZ(ARM64Reg::X0);
ADD(ARM64Reg::SP, ARM64Reg::X0, 0);
SetJumpTarget(no_fake_stack);
STR(IndexType::Unsigned, ARM64Reg::X0, PPC_REG, PPCSTATE_OFF(stored_stack_pointer));
// Push {nullptr; -1} as invalid destination on the stack.
MOVI2R(ARM64Reg::X0, 0xFFFFFFFF);
STP(IndexType::Pre, ARM64Reg::ZR, ARM64Reg::X0, ARM64Reg::SP, -16);
// Store the stack pointer, so we can reset it if the BLR optimization fails.
ADD(ARM64Reg::X0, ARM64Reg::SP, 0);
STR(IndexType::Unsigned, ARM64Reg::X0, PPC_REG, PPCSTATE_OFF(stored_stack_pointer));
// The PC will be loaded into DISPATCHER_PC after the call to CoreTiming::Advance().
// Advance() does an exception check so we don't know what PC to use until afterwards.
FixupBranch to_start_of_timing_slice = B();
@ -204,9 +195,9 @@ void JitArm64::GenerateAsm()
if (enable_debugging)
SetJumpTarget(debug_exit);
// Reset the stack pointer, as the BLR optimization have touched it.
LDR(IndexType::Unsigned, ARM64Reg::X0, ARM64Reg::X1,
MOVPage2R(ARM64Reg::X1, &m_saved_stack_pointer));
// Reset the stack pointer, since the BLR optimization may have pushed things onto the stack
// without popping them.
LDR(IndexType::Unsigned, ARM64Reg::X0, PPC_REG, PPCSTATE_OFF(stored_stack_pointer));
ADD(ARM64Reg::SP, ARM64Reg::X0, 0);
m_float_emit.ABI_PopRegisters(regs_to_save_fpr, ARM64Reg::X30);

139
Source/Core/Core/PowerPC/JitCommon/JitBase.cpp
View File

@ -3,15 +3,53 @@
#include "Core/PowerPC/JitCommon/JitBase.h"
#include "Common/Align.h"
#include "Common/CommonTypes.h"
#include "Common/MemoryUtil.h"
#include "Common/Thread.h"
#include "Core/Config/MainSettings.h"
#include "Core/ConfigManager.h"
#include "Core/Core.h"
#include "Core/CoreTiming.h"
#include "Core/HW/CPU.h"
#include "Core/PowerPC/PPCAnalyst.h"
#include "Core/PowerPC/PowerPC.h"
#include "Core/System.h"
#ifdef _WIN32
#include <windows.h>
#include <processthreadsapi.h>
#else
#include <unistd.h>
#endif
// The BLR optimization is nice, but it means that JITted code can overflow the
// native stack by repeatedly running BL. (The chance of this happening in any
// retail game is close to 0, but correctness is correctness...) Also, the
// overflow might not happen directly in the JITted code but in a C++ function
// called from it, so we can't just adjust RSP in the case of a fault.
// Instead, we have to have extra stack space preallocated under the fault
// point which allows the code to continue, after wiping the JIT cache so we
// can reset things at a safe point. Once this condition trips, the
// optimization is permanently disabled, under the assumption this will never
// happen in practice.
// On Unix, we just mark an appropriate region of the stack as PROT_NONE and
// handle it the same way as fastmem faults. It's safe to take a fault with a
// bad RSP, because on Linux we can use sigaltstack and on OS X we're already
// on a separate thread.
// Windows is... under-documented.
// It already puts guard pages so it can automatically grow the stack and it
// doesn't look like there is a way to hook into a guard page fault and implement
// our own logic.
// But when windows reaches the last guard page, it raises a "Stack Overflow"
// exception which we can hook into, however by default it leaves you with less
// than 4kb of stack. So we use SetThreadStackGuarantee to trigger the Stack
// Overflow early while we still have 256kb of stack remaining.
// After resetting the stack to the top, we call _resetstkoflw() to restore
// the guard page at the 256kb mark.
const u8* JitBase::Dispatch(JitBase& jit)
{
return jit.GetBlockCache()->Dispatch();
@ -72,6 +110,107 @@ void JitBase::RefreshConfig()
analyzer.SetDivByZeroExceptionsEnabled(m_enable_div_by_zero_exceptions);
}
void JitBase::InitBLROptimization()
{
m_enable_blr_optimization = jo.enableBlocklink && m_fastmem_enabled && !m_enable_debugging;
m_cleanup_after_stackfault = false;
}
void JitBase::ProtectStack()
{
if (!m_enable_blr_optimization)
return;
#ifdef _WIN32
ULONG reserveSize = SAFE_STACK_SIZE;
SetThreadStackGuarantee(&reserveSize);
#else
auto [stack_addr, stack_size] = Common::GetCurrentThreadStack();
const uintptr_t stack_base_addr = reinterpret_cast<uintptr_t>(stack_addr);
const uintptr_t stack_middle_addr = reinterpret_cast<uintptr_t>(&stack_addr);
if (stack_middle_addr < stack_base_addr || stack_middle_addr >= stack_base_addr + stack_size)
{
PanicAlertFmt("Failed to get correct stack base");
m_enable_blr_optimization = false;
return;
}
const long page_size = sysconf(_SC_PAGESIZE);
if (page_size <= 0)
{
PanicAlertFmt("Failed to get page size");
m_enable_blr_optimization = false;
return;
}
const uintptr_t stack_guard_addr = Common::AlignUp(stack_base_addr + GUARD_OFFSET, page_size);
if (stack_guard_addr >= stack_middle_addr ||
stack_middle_addr - stack_guard_addr < GUARD_SIZE + MIN_UNSAFE_STACK_SIZE)
{
PanicAlertFmt("Stack is too small for BLR optimization (size {:x}, base {:x}, current stack "
"pointer {:x}, alignment {:x})",
stack_size, stack_base_addr, stack_middle_addr, page_size);
m_enable_blr_optimization = false;
return;
}
m_stack_guard = reinterpret_cast<u8*>(stack_guard_addr);
Common::ReadProtectMemory(m_stack_guard, GUARD_SIZE);
#endif
}
void JitBase::UnprotectStack()
{
#ifndef _WIN32
if (m_stack_guard)
{
Common::UnWriteProtectMemory(m_stack_guard, GUARD_SIZE);
m_stack_guard = nullptr;
}
#endif
}
bool JitBase::HandleStackFault()
{
// It's possible the stack fault might have been caused by something other than
// the BLR optimization. If the fault was triggered from another thread, or
// when BLR optimization isn't enabled then there is nothing we can do about the fault.
// Return false so the regular stack overflow handler can trigger (which crashes)
if (!m_enable_blr_optimization || !Core::IsCPUThread())
return false;
WARN_LOG_FMT(POWERPC, "BLR cache disabled due to excessive BL in the emulated program.");
UnprotectStack();
m_enable_blr_optimization = false;
// We're going to need to clear the whole cache to get rid of the bad
// CALLs, but we can't yet. Fake the downcount so we're forced to the
// dispatcher (no block linking), and clear the cache so we're sent to
// Jit. In the case of Windows, we will also need to call _resetstkoflw()
// to reset the guard page.
// Yeah, it's kind of gross.
GetBlockCache()->InvalidateICache(0, 0xffffffff, true);
Core::System::GetInstance().GetCoreTiming().ForceExceptionCheck(0);
m_cleanup_after_stackfault = true;
return true;
}
void JitBase::CleanUpAfterStackFault()
{
if (m_cleanup_after_stackfault)
{
ClearCache();
m_cleanup_after_stackfault = false;
#ifdef _WIN32
// The stack is in an invalid state with no guard page, reset it.
_resetstkoflw();
#endif
}
}
bool JitBase::CanMergeNextInstructions(int count) const
{
if (CPU::IsStepping() || js.instructionsLeft < count)

17
Source/Core/Core/PowerPC/JitCommon/JitBase.h
View File

@ -54,6 +54,12 @@ protected:
#endif
};
static constexpr size_t SAFE_STACK_SIZE = 256 * 1024;
static constexpr size_t MIN_UNSAFE_STACK_SIZE = 192 * 1024;
static constexpr size_t MIN_STACK_SIZE = SAFE_STACK_SIZE + MIN_UNSAFE_STACK_SIZE;
static constexpr size_t GUARD_SIZE = 64 * 1024;
static constexpr size_t GUARD_OFFSET = SAFE_STACK_SIZE - GUARD_SIZE;
struct JitOptions
{
bool enableBlocklink;
@ -138,8 +144,17 @@ protected:
bool m_pause_on_panic_enabled = false;
bool m_accurate_cpu_cache_enabled = false;
bool m_enable_blr_optimization = false;
bool m_cleanup_after_stackfault = false;
u8* m_stack_guard = nullptr;
void RefreshConfig();
void InitBLROptimization();
void ProtectStack();
void UnprotectStack();
void CleanUpAfterStackFault();
bool CanMergeNextInstructions(int count) const;
void UpdateMemoryAndExceptionOptions();
@ -160,7 +175,7 @@ public:
virtual const CommonAsmRoutinesBase* GetAsmRoutines() = 0;
virtual bool HandleFault(uintptr_t access_address, SContext* ctx) = 0;
virtual bool HandleStackFault() { return false; }
bool HandleStackFault();
static constexpr std::size_t code_buffer_size = 32000;