// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#include <cinttypes>
#include <memory>
#include "common/signal_chain.h"
#include "core/arm/nce/arm_nce.h"
#include "core/arm/nce/patch.h"
#include "core/core.h"
#include "core/memory.h"
#include "core/hle/kernel/k_process.h"
#include <signal.h>
#include <sys/syscall.h>
#include <unistd.h>
namespace Core {
namespace {
struct sigaction g_orig_action;
// Verify assembly offsets.
using NativeExecutionParameters = Kernel::KThread::NativeExecutionParameters;
static_assert(offsetof(NativeExecutionParameters, native_context) == TpidrEl0NativeContext);
static_assert(offsetof(NativeExecutionParameters, lock) == TpidrEl0Lock);
static_assert(offsetof(NativeExecutionParameters, magic) == TpidrEl0TlsMagic);
fpsimd_context* GetFloatingPointState(mcontext_t& host_ctx) {
_aarch64_ctx* header = reinterpret_cast<_aarch64_ctx*>(&host_ctx.__reserved);
while (header->magic != FPSIMD_MAGIC) {
header = reinterpret_cast<_aarch64_ctx*>(reinterpret_cast<char*>(header) + header->size);
}
return reinterpret_cast<fpsimd_context*>(header);
}
} // namespace
void* ARM_NCE::RestoreGuestContext(void* raw_context) {
// Retrieve the host context.
auto& host_ctx = static_cast<ucontext_t*>(raw_context)->uc_mcontext;
// Thread-local parameters will be located in x9.
auto* tpidr = reinterpret_cast<NativeExecutionParameters*>(host_ctx.regs[9]);
auto* guest_ctx = static_cast<GuestContext*>(tpidr->native_context);
// Retrieve the host floating point state.
auto* fpctx = GetFloatingPointState(host_ctx);
// Save host callee-saved registers.
std::memcpy(guest_ctx->host_ctx.host_saved_vregs.data(), &fpctx->vregs[8],
sizeof(guest_ctx->host_ctx.host_saved_vregs));
std::memcpy(guest_ctx->host_ctx.host_saved_regs.data(), &host_ctx.regs[19],
sizeof(guest_ctx->host_ctx.host_saved_regs));
// Save stack pointer.
guest_ctx->host_ctx.host_sp = host_ctx.sp;
// Restore all guest state except tpidr_el0.
host_ctx.sp = guest_ctx->sp;
host_ctx.pc = guest_ctx->pc;
host_ctx.pstate = guest_ctx->pstate;
fpctx->fpcr = guest_ctx->fpcr;
fpctx->fpsr = guest_ctx->fpsr;
std::memcpy(host_ctx.regs, guest_ctx->cpu_registers.data(), sizeof(host_ctx.regs));
std::memcpy(fpctx->vregs, guest_ctx->vector_registers.data(), sizeof(fpctx->vregs));
// Return the new thread-local storage pointer.
return tpidr;
}
void ARM_NCE::SaveGuestContext(GuestContext* guest_ctx, void* raw_context) {
// Retrieve the host context.
auto& host_ctx = static_cast<ucontext_t*>(raw_context)->uc_mcontext;
// Retrieve the host floating point state.
auto* fpctx = GetFloatingPointState(host_ctx);
// Save all guest registers except tpidr_el0.
std::memcpy(guest_ctx->cpu_registers.data(), host_ctx.regs, sizeof(host_ctx.regs));
std::memcpy(guest_ctx->vector_registers.data(), fpctx->vregs, sizeof(fpctx->vregs));
guest_ctx->fpsr = fpctx->fpsr;
guest_ctx->fpcr = fpctx->fpcr;
guest_ctx->pstate = static_cast<u32>(host_ctx.pstate);
guest_ctx->pc = host_ctx.pc;
guest_ctx->sp = host_ctx.sp;
// Restore stack pointer.
host_ctx.sp = guest_ctx->host_ctx.host_sp;
// Restore host callee-saved registers.
std::memcpy(&host_ctx.regs[19], guest_ctx->host_ctx.host_saved_regs.data(),
sizeof(guest_ctx->host_ctx.host_saved_regs));
std::memcpy(&fpctx->vregs[8], guest_ctx->host_ctx.host_saved_vregs.data(),
sizeof(guest_ctx->host_ctx.host_saved_vregs));
// Return from the call on exit by setting pc to x30.
host_ctx.pc = guest_ctx->host_ctx.host_saved_regs[11];
// Clear esr_el1 and return it.
host_ctx.regs[0] = guest_ctx->esr_el1.exchange(0);
}
bool ARM_NCE::HandleGuestFault(GuestContext* guest_ctx, void* raw_info, void* raw_context) {
auto& host_ctx = static_cast<ucontext_t*>(raw_context)->uc_mcontext;
auto* info = static_cast<siginfo_t*>(raw_info);
// Try to handle an invalid access.
// TODO: handle accesses which split a page?
const Common::ProcessAddress addr =
(reinterpret_cast<u64>(info->si_addr) & ~Memory::YUZU_PAGEMASK);
if (guest_ctx->system->ApplicationMemory().InvalidateNCE(addr, Memory::YUZU_PAGESIZE)) {
// We handled the access successfully and are returning to guest code.
return true;
}
// We can't handle the access, so determine why we crashed.
const bool is_prefetch_abort = host_ctx.pc == reinterpret_cast<u64>(info->si_addr);
// For data aborts, skip the instruction and return to guest code.
// This will allow games to continue in many scenarios where they would otherwise crash.
if (!is_prefetch_abort) {
host_ctx.pc += 4;
return true;
}
// This is a prefetch abort.
guest_ctx->esr_el1.fetch_or(static_cast<u64>(HaltReason::PrefetchAbort));
// Forcibly mark the context as locked. We are still running.
// We may race with SignalInterrupt here:
// - If we lose the race, then SignalInterrupt will send us a signal we are masking,
// and it will do nothing when it is unmasked, as we have already left guest code.
// - If we win the race, then SignalInterrupt will wait for us to unlock first.
auto& thread_params = guest_ctx->parent->running_thread->GetNativeExecutionParameters();
thread_params.lock.store(SpinLockLocked);
// Return to host.
SaveGuestContext(guest_ctx, raw_context);
return false;
}
void ARM_NCE::HandleHostFault(int sig, void* raw_info, void* raw_context) {
return g_orig_action.sa_sigaction(sig, static_cast<siginfo_t*>(raw_info), raw_context);
}
HaltReason ARM_NCE::RunJit() {
// Get the thread parameters.
// TODO: pass the current thread down from ::Run
auto* thread = Kernel::GetCurrentThreadPointer(system.Kernel());
auto* thread_params = &thread->GetNativeExecutionParameters();
{
// Lock our core context.
std::scoped_lock lk{lock};
// We should not be running.
ASSERT(running_thread == nullptr);
// Check if we need to run. If we have already been halted, we are done.
u64 halt = guest_ctx.esr_el1.exchange(0);
if (halt != 0) {
return static_cast<HaltReason>(halt);
}
// Mark that we are running.
running_thread = thread;
// Acquire the lock on the thread parameters.
// This allows us to force synchronization with SignalInterrupt.
LockThreadParameters(thread_params);
}
// Assign current members.
guest_ctx.parent = this;
thread_params->native_context = &guest_ctx;
thread_params->tpidr_el0 = guest_ctx.tpidr_el0;
thread_params->tpidrro_el0 = guest_ctx.tpidrro_el0;
thread_params->is_running = true;
HaltReason halt{};
// TODO: finding and creating the post handler needs to be locked
// to deal with dynamic loading of NROs.
const auto& post_handlers = system.ApplicationProcess()->GetPostHandlers();
if (auto it = post_handlers.find(guest_ctx.pc); it != post_handlers.end()) {
halt = ReturnToRunCodeByTrampoline(thread_params, &guest_ctx, it->second);
} else {
halt = ReturnToRunCodeByExceptionLevelChange(thread_id, thread_params);
}
// Unload members.
// The thread does not change, so we can persist the old reference.
guest_ctx.tpidr_el0 = thread_params->tpidr_el0;
thread_params->native_context = nullptr;
thread_params->is_running = false;
// Unlock the thread parameters.
UnlockThreadParameters(thread_params);
{
// Lock the core context.
std::scoped_lock lk{lock};
// On exit, we no longer have an active thread.
running_thread = nullptr;
}
// Return the halt reason.
return halt;
}
HaltReason ARM_NCE::StepJit() {
return HaltReason::StepThread;
}
u32 ARM_NCE::GetSvcNumber() const {
return guest_ctx.svc_swi;
}
ARM_NCE::ARM_NCE(System& system_, bool uses_wall_clock_, std::size_t core_index_)
: ARM_Interface{system_, uses_wall_clock_}, core_index{core_index_} {
guest_ctx.system = &system_;
}
ARM_NCE::~ARM_NCE() = default;
void ARM_NCE::Initialize() {
thread_id = gettid();
// Setup our signals
static std::once_flag flag;
std::call_once(flag, [] {
using HandlerType = decltype(sigaction::sa_sigaction);
sigset_t signal_mask;
sigemptyset(&signal_mask);
sigaddset(&signal_mask, ReturnToRunCodeByExceptionLevelChangeSignal);
sigaddset(&signal_mask, BreakFromRunCodeSignal);
sigaddset(&signal_mask, GuestFaultSignal);
struct sigaction return_to_run_code_action {};
return_to_run_code_action.sa_flags = SA_SIGINFO | SA_ONSTACK;
return_to_run_code_action.sa_sigaction = reinterpret_cast<HandlerType>(
&ARM_NCE::ReturnToRunCodeByExceptionLevelChangeSignalHandler);
return_to_run_code_action.sa_mask = signal_mask;
Common::SigAction(ReturnToRunCodeByExceptionLevelChangeSignal, &return_to_run_code_action,
nullptr);
struct sigaction break_from_run_code_action {};
break_from_run_code_action.sa_flags = SA_SIGINFO | SA_ONSTACK;
break_from_run_code_action.sa_sigaction =
reinterpret_cast<HandlerType>(&ARM_NCE::BreakFromRunCodeSignalHandler);
break_from_run_code_action.sa_mask = signal_mask;
Common::SigAction(BreakFromRunCodeSignal, &break_from_run_code_action, nullptr);
struct sigaction fault_action {};
fault_action.sa_flags = SA_SIGINFO | SA_ONSTACK | SA_RESTART;
fault_action.sa_sigaction =
reinterpret_cast<HandlerType>(&ARM_NCE::GuestFaultSignalHandler);
fault_action.sa_mask = signal_mask;
Common::SigAction(GuestFaultSignal, &fault_action, &g_orig_action);
// Simplify call for g_orig_action.
// These fields occupy the same space in memory, so this should be a no-op in practice.
if (!(g_orig_action.sa_flags & SA_SIGINFO)) {
g_orig_action.sa_sigaction =
reinterpret_cast<decltype(g_orig_action.sa_sigaction)>(g_orig_action.sa_handler);
}
});
}
void ARM_NCE::SetPC(u64 pc) {
guest_ctx.pc = pc;
}
u64 ARM_NCE::GetPC() const {
return guest_ctx.pc;
}
u64 ARM_NCE::GetSP() const {
return guest_ctx.sp;
}
u64 ARM_NCE::GetReg(int index) const {
return guest_ctx.cpu_registers[index];
}
void ARM_NCE::SetReg(int index, u64 value) {
guest_ctx.cpu_registers[index] = value;
}
u128 ARM_NCE::GetVectorReg(int index) const {
return guest_ctx.vector_registers[index];
}
void ARM_NCE::SetVectorReg(int index, u128 value) {
guest_ctx.vector_registers[index] = value;
}
u32 ARM_NCE::GetPSTATE() const {
return guest_ctx.pstate;
}
void ARM_NCE::SetPSTATE(u32 pstate) {
guest_ctx.pstate = pstate;
}
u64 ARM_NCE::GetTlsAddress() const {
return guest_ctx.tpidrro_el0;
}
void ARM_NCE::SetTlsAddress(u64 address) {
guest_ctx.tpidrro_el0 = address;
}
u64 ARM_NCE::GetTPIDR_EL0() const {
return guest_ctx.tpidr_el0;
}
void ARM_NCE::SetTPIDR_EL0(u64 value) {
guest_ctx.tpidr_el0 = value;
}
void ARM_NCE::SaveContext(ThreadContext64& ctx) const {
ctx.cpu_registers = guest_ctx.cpu_registers;
ctx.sp = guest_ctx.sp;
ctx.pc = guest_ctx.pc;
ctx.pstate = guest_ctx.pstate;
ctx.vector_registers = guest_ctx.vector_registers;
ctx.fpcr = guest_ctx.fpcr;
ctx.fpsr = guest_ctx.fpsr;
ctx.tpidr = guest_ctx.tpidr_el0;
}
void ARM_NCE::LoadContext(const ThreadContext64& ctx) {
guest_ctx.cpu_registers = ctx.cpu_registers;
guest_ctx.sp = ctx.sp;
guest_ctx.pc = ctx.pc;
guest_ctx.pstate = ctx.pstate;
guest_ctx.vector_registers = ctx.vector_registers;
guest_ctx.fpcr = ctx.fpcr;
guest_ctx.fpsr = ctx.fpsr;
guest_ctx.tpidr_el0 = ctx.tpidr;
}
void ARM_NCE::SignalInterrupt() {
// Lock core context.
std::scoped_lock lk{lock};
// Add break loop condition.
guest_ctx.esr_el1.fetch_or(static_cast<u64>(HaltReason::BreakLoop));
// If there is no thread running, we are done.
if (running_thread == nullptr) {
return;
}
// Lock the thread context.
auto* params = &running_thread->GetNativeExecutionParameters();
LockThreadParameters(params);
if (params->is_running) {
// We should signal to the running thread.
// The running thread will unlock the thread context.
syscall(SYS_tkill, thread_id, BreakFromRunCodeSignal);
} else {
// If the thread is no longer running, we have nothing to do.
UnlockThreadParameters(params);
}
}
void ARM_NCE::ClearInterrupt() {
guest_ctx.esr_el1 = {};
}
void ARM_NCE::ClearInstructionCache() {
// TODO: This is not possible to implement correctly on Linux because
// we do not have any access to ic iallu.
// Require accesses to complete.
std::atomic_thread_fence(std::memory_order_seq_cst);
}
void ARM_NCE::InvalidateCacheRange(u64 addr, std::size_t size) {
this->ClearInstructionCache();
}
void ARM_NCE::ClearExclusiveState() {
// No-op.
}
void ARM_NCE::PageTableChanged(Common::PageTable& page_table,
std::size_t new_address_space_size_in_bits) {
// No-op. Page table is never used.
}
} // namespace Core
