kern: SvcReturnFromException

This commit is contained in:
Michael Scire 2020-07-31 05:52:59 -07:00 committed by SciresM
parent 8cd81b3092
commit 5d462c626c
11 changed files with 647 additions and 56 deletions

View file

@ -15,10 +15,52 @@
*/
#include <mesosphere.hpp>
namespace ams::kern::svc {
void RestoreContext(uintptr_t sp);
}
namespace ams::kern::arch::arm64 {
namespace {
constexpr inline u32 El0PsrMask = 0xFF0FFE20;
enum EsrEc : u32 {
EsrEc_Unknown = 0b000000,
EsrEc_WaitForInterruptOrEvent = 0b000001,
EsrEc_Cp15McrMrc = 0b000011,
EsrEc_Cp15McrrMrrc = 0b000100,
EsrEc_Cp14McrMrc = 0b000101,
EsrEc_FpAccess = 0b000111,
EsrEc_Cp14Mrrc = 0b001100,
EsrEc_BranchTarget = 0b001101,
EsrEc_IllegalExecution = 0b001110,
EsrEc_Svc32 = 0b010001,
EsrEc_Svc64 = 0b010101,
EsrEc_SystemInstruction64 = 0b011000,
EsrEc_SveZen = 0b011001,
EsrEc_PointerAuthInstruction = 0b011100,
EsrEc_InstructionAbortEl0 = 0b100000,
EsrEc_InstructionAbortEl1 = 0b100001,
EsrEc_PcAlignmentFault = 0b100010,
EsrEc_DataAbortEl0 = 0b100100,
EsrEc_DataAbortEl1 = 0b100101,
EsrEc_SpAlignmentFault = 0b100110,
EsrEc_FpException32 = 0b101000,
EsrEc_FpException64 = 0b101100,
EsrEc_SErrorInterrupt = 0b101111,
EsrEc_BreakPointEl0 = 0b110000,
EsrEc_BreakPointEl1 = 0b110001,
EsrEc_SoftwareStepEl0 = 0b110010,
EsrEc_SoftwareStepEl1 = 0b110011,
EsrEc_WatchPointEl0 = 0b110100,
EsrEc_WatchPointEl1 = 0b110101,
EsrEc_BkptInstruction = 0b111000,
EsrEc_BrkInstruction = 0b111100,
};
constexpr u32 GetInstructionData(const KExceptionContext *context, u64 esr) {
/* Check for THUMB usermode */
if ((context->psr & 0x3F) == 0x30) {
@ -35,61 +77,234 @@ namespace ams::kern::arch::arm64 {
}
void HandleUserException(KExceptionContext *context, u64 esr, u64 far, u64 afsr0, u64 afsr1, u32 data) {
KProcess *cur_process = GetCurrentProcessPointer();
KProcess &cur_process = GetCurrentProcess();
bool should_process_user_exception = KTargetSystem::IsUserExceptionHandlersEnabled();
MESOSPHERE_LOG("User Exception occurred in %s\n", cur_process->GetName());
for (size_t i = 0; i < 31; i++) {
MESOSPHERE_LOG("X[%02zu] = %016lx\n", i, context->x[i]);
}
MESOSPHERE_LOG("PC = %016lx\n", context->pc);
MESOSPHERE_LOG("SP = %016lx\n", context->sp);
/* Dump the page tables. */
/* GetCurrentProcess().GetPageTable().DumpTable(); */
GetCurrentProcess().GetPageTable().DumpMemoryBlocks();
MESOSPHERE_PANIC("Unhandled Exception in User Mode\n");
const u64 ec = (esr >> 26) & 0x3F;
switch (ec) {
case 0x0: /* Unknown */
case 0xE: /* Illegal Execution State */
case 0x11: /* SVC instruction from Aarch32 */
case 0x15: /* SVC instruction from Aarch64 */
case 0x22: /* PC Misalignment */
case 0x26: /* SP Misalignment */
case 0x2F: /* SError */
case 0x30: /* Breakpoint from lower EL */
case 0x32: /* SoftwareStep from lower EL */
case 0x34: /* Watchpoint from lower EL */
case 0x38: /* BKPT instruction */
case 0x3C: /* BRK instruction */
case EsrEc_Unknown:
case EsrEc_IllegalExecution:
case EsrEc_Svc32:
case EsrEc_Svc64:
case EsrEc_PcAlignmentFault:
case EsrEc_SpAlignmentFault:
case EsrEc_SErrorInterrupt:
case EsrEc_BreakPointEl0:
case EsrEc_SoftwareStepEl0:
case EsrEc_WatchPointEl0:
case EsrEc_BkptInstruction:
case EsrEc_BrkInstruction:
break;
default:
{
MESOSPHERE_TODO("Get memory state.");
/* If state is KMemoryState_Code and the user can't read it, set should_process_user_exception = true; */
/* If the fault address's state is KMemoryState_Code and the user can't read the address, force processing exception. */
KMemoryInfo info;
ams::svc::PageInfo pi;
if (R_SUCCEEDED(cur_process.GetPageTable().QueryInfo(std::addressof(info), std::addressof(pi), far))) {
if (info.GetState() == KMemoryState_Code && ((info.GetPermission() & KMemoryPermission_UserRead) != KMemoryPermission_UserRead)) {
should_process_user_exception = true;
}
}
}
break;
}
if (should_process_user_exception) {
MESOSPHERE_TODO("Process the user exception.");
/* If we should process the user exception (and it's not a breakpoint), try to enter. */
const bool is_software_break = (ec == EsrEc_Unknown || ec == EsrEc_IllegalExecution || ec == EsrEc_BkptInstruction || ec == EsrEc_BrkInstruction);
const bool is_breakpoint = (ec == EsrEc_BreakPointEl0 || ec == EsrEc_SoftwareStepEl0 || ec == EsrEc_WatchPointEl0);
if ((should_process_user_exception) &&
!(is_software_break && cur_process.IsAttachedToDebugger() && KDebug::IsBreakInstruction(data, context->psr)) &&
!(is_breakpoint))
{
if (cur_process.EnterUserException()) {
/* Fill out the exception info. */
const bool is_aarch64 = (context->psr & 0x10) == 0;
if (is_aarch64) {
/* 64-bit. */
ams::svc::aarch64::ExceptionInfo *info = std::addressof(GetPointer<ams::svc::aarch64::ProcessLocalRegion>(cur_process.GetProcessLocalRegionAddress())->exception_info);
for (size_t i = 0; i < util::size(info->r); ++i) {
info->r[i] = context->x[i];
}
info->sp = context->sp;
info->lr = context->x[30];
info->pc = context->pc;
info->pstate = (context->psr & El0PsrMask);
info->afsr0 = afsr0;
info->afsr1 = afsr1;
info->esr = esr;
info->far = far;
} else {
/* 32-bit. */
ams::svc::aarch32::ExceptionInfo *info = std::addressof(GetPointer<ams::svc::aarch32::ProcessLocalRegion>(cur_process.GetProcessLocalRegionAddress())->exception_info);
for (size_t i = 0; i < util::size(info->r); ++i) {
info->r[i] = context->x[i];
}
info->sp = context->x[13];
info->lr = context->x[14];
info->pc = context->pc;
info->flags = 1;
info->status_64.pstate = (context->psr & El0PsrMask);
info->status_64.afsr0 = afsr0;
info->status_64.afsr1 = afsr1;
info->status_64.esr = esr;
info->status_64.far = far;
}
/* Save the debug parameters to the current thread. */
GetCurrentThread().SaveDebugParams(far, esr, data);
/* Get the exception type. */
u32 type;
switch (ec) {
case EsrEc_Unknown:
case EsrEc_IllegalExecution:
case EsrEc_Cp15McrMrc:
case EsrEc_Cp15McrrMrrc:
case EsrEc_Cp14McrMrc:
case EsrEc_Cp14Mrrc:
case EsrEc_SystemInstruction64:
case EsrEc_BkptInstruction:
case EsrEc_BrkInstruction:
type = ams::svc::ExceptionType_InstructionAbort;
break;
case EsrEc_PcAlignmentFault:
type = ams::svc::ExceptionType_UnalignedInstruction;
break;
case EsrEc_SpAlignmentFault:
type = ams::svc::ExceptionType_UnalignedData;
break;
case EsrEc_Svc32:
case EsrEc_Svc64:
type = ams::svc::ExceptionType_InvalidSystemCall;
break;
case EsrEc_SErrorInterrupt:
type = ams::svc::ExceptionType_MemorySystemError;
break;
case EsrEc_InstructionAbortEl0:
type = ams::svc::ExceptionType_InstructionAbort;
break;
case EsrEc_DataAbortEl0:
default:
type = ams::svc::ExceptionType_DataAbort;
break;
}
/* We want to enter at the process entrypoint, with x0 = type. */
context->pc = GetInteger(cur_process.GetEntryPoint());
context->x[0] = type;
if (is_aarch64) {
context->x[1] = GetInteger(cur_process.GetProcessLocalRegionAddress() + __builtin_offsetof(ams::svc::aarch64::ProcessLocalRegion, exception_info));
auto *plr = GetPointer<ams::svc::aarch64::ProcessLocalRegion>(cur_process.GetProcessLocalRegionAddress());
context->sp = util::AlignDown(reinterpret_cast<uintptr_t>(plr->data) + sizeof(plr->data), 0x10);
context->psr = 0;
} else {
context->x[1] = GetInteger(cur_process.GetProcessLocalRegionAddress() + __builtin_offsetof(ams::svc::aarch32::ProcessLocalRegion, exception_info));
auto *plr = GetPointer<ams::svc::aarch32::ProcessLocalRegion>(cur_process.GetProcessLocalRegionAddress());
context->x[13] = util::AlignDown(reinterpret_cast<uintptr_t>(plr->data) + sizeof(plr->data), 0x10);
context->psr = 0x10;
}
/* Set exception SVC permissions. */
cur_process.CopyEnterExceptionSvcPermissionsTo(GetCurrentThread().GetStackParametersForExceptionSvcPermission());
return;
}
}
{
MESOSPHERE_TODO("Process for KDebug.");
/* Collect additional information based on the ec. */
ams::svc::DebugException exception;
uintptr_t param2 = 0;
uintptr_t param3 = 0;
switch (ec) {
case EsrEc_Unknown:
case EsrEc_IllegalExecution:
case EsrEc_BkptInstruction:
case EsrEc_BrkInstruction:
{
exception = ams::svc::DebugException_UndefinedInstruction;
param2 = far;
param3 = data;
}
break;
case EsrEc_PcAlignmentFault:
case EsrEc_SpAlignmentFault:
{
exception = ams::svc::DebugException_AlignmentFault;
param2 = far;
}
break;
case EsrEc_Svc32:
case EsrEc_Svc64:
{
exception = ams::svc::DebugException_UndefinedSystemCall;
param2 = far;
param3 = (esr & 0xFF);
}
break;
case EsrEc_BreakPointEl0:
case EsrEc_SoftwareStepEl0:
{
exception = ams::svc::DebugException_BreakPoint;
param2 = far;
param3 = ams::svc::BreakPointType_HardwareInstruction;
}
break;
case EsrEc_WatchPointEl0:
{
exception = ams::svc::DebugException_BreakPoint;
param2 = far;
param3 = ams::svc::BreakPointType_HardwareInstruction;
}
break;
case EsrEc_SErrorInterrupt:
{
exception = ams::svc::DebugException_MemorySystemError;
param2 = far;
}
break;
case EsrEc_InstructionAbortEl0:
{
exception = ams::svc::DebugException_InstructionAbort;
param2 = far;
}
break;
case EsrEc_DataAbortEl0:
default:
{
exception = ams::svc::DebugException_DataAbort;
param2 = far;
}
break;
}
MESOSPHERE_TODO("cur_process->GetProgramId()");
MESOSPHERE_RELEASE_LOG("Exception occurred. %016lx\n", 0ul);
/* Process the debug event. */
Result result = KDebug::OnDebugEvent(ams::svc::DebugEvent_Exception, exception, param2, param3);
MESOSPHERE_TODO("if (!svc::ResultNotHandled::Includes(res)) { debug process }.");
/* If we should stop processing the exception, do so. */
if (svc::ResultStopProcessingException::Includes(result)) {
return;
}
/* Print that an exception occurred. */
MESOSPHERE_RELEASE_LOG("Exception occurred. %016lx\n", GetCurrentProcess().GetProgramId());
/* If the SVC is handled, handle it. */
if (!svc::ResultNotHandled::Includes(result)) {
/* If we successfully enter jit debug, stop processing the exception. */
if (cur_process.EnterJitDebug(ams::svc::DebugEvent_Exception, exception, param2, param3)) {
return;
}
}
}
MESOSPHERE_TODO("cur_process->Exit();");
(void)cur_process;
/* Exit the current process. */
cur_process.Exit();
}
}
@ -99,6 +314,149 @@ namespace ams::kern::arch::arm64 {
KThreadContext::FpuContextSwitchHandler(GetCurrentThreadPointer());
}
/* NOTE: This function is called from ASM. */
void ReturnFromException(Result user_result) {
/* Get the current thread. */
KThread *cur_thread = GetCurrentThreadPointer();
/* Get the current exception context. */
KExceptionContext *e_ctx = GetExceptionContext(cur_thread);
/* Get the current process. */
KProcess &cur_process = GetCurrentProcess();
/* Read the exception info that userland put in tls. */
union {
ams::svc::aarch64::ExceptionInfo info64;
ams::svc::aarch32::ExceptionInfo info32;
} info = {};
const bool is_aarch64 = (e_ctx->psr & 0x10) == 0;
if (is_aarch64) {
/* We're 64-bit. */
info.info64 = GetPointer<ams::svc::aarch64::ProcessLocalRegion>(cur_process.GetProcessLocalRegionAddress())->exception_info;
} else {
/* We're 32-bit. */
info.info32 = GetPointer<ams::svc::aarch32::ProcessLocalRegion>(cur_process.GetProcessLocalRegionAddress())->exception_info;
}
/* Try to leave the user exception. */
if (cur_process.LeaveUserException()) {
/* We left user exception. Alter our SVC permissions accordingly. */
cur_process.CopyLeaveExceptionSvcPermissionsTo(cur_thread->GetStackParametersForExceptionSvcPermission());
/* Copy the user context to the thread context. */
if (is_aarch64) {
for (size_t i = 0; i < util::size(info.info64.r); ++i) {
e_ctx->x[i] = info.info64.r[i];
}
e_ctx->x[30] = info.info64.lr;
e_ctx->sp = info.info64.sp;
e_ctx->pc = info.info64.pc;
e_ctx->psr = (info.info64.pstate & El0PsrMask) | (e_ctx->psr & ~El0PsrMask);
} else {
for (size_t i = 0; i < util::size(info.info32.r); ++i) {
e_ctx->x[i] = info.info32.r[i];
}
e_ctx->x[14] = info.info32.lr;
e_ctx->x[13] = info.info32.sp;
e_ctx->pc = info.info32.pc;
e_ctx->psr = (info.info32.status_64.pstate & El0PsrMask) | (e_ctx->psr & ~El0PsrMask);
}
/* Note that PC was adjusted. */
e_ctx->write = 1;
if (R_SUCCEEDED(user_result)) {
/* If result handling succeeded, just restore the context. */
svc::RestoreContext(reinterpret_cast<uintptr_t>(e_ctx));
} else {
/* Restore the debug params for the exception. */
uintptr_t far, esr, data;
GetCurrentThread().RestoreDebugParams(std::addressof(far), std::addressof(esr), std::addressof(data));
/* Collect additional information based on the ec. */
ams::svc::DebugException exception;
uintptr_t param2 = 0;
uintptr_t param3 = 0;
switch ((esr >> 26) & 0x3F) {
case EsrEc_Unknown:
case EsrEc_IllegalExecution:
case EsrEc_BkptInstruction:
case EsrEc_BrkInstruction:
{
exception = ams::svc::DebugException_UndefinedInstruction;
param2 = far;
param3 = data;
}
break;
case EsrEc_PcAlignmentFault:
case EsrEc_SpAlignmentFault:
{
exception = ams::svc::DebugException_AlignmentFault;
param2 = far;
}
break;
case EsrEc_Svc32:
case EsrEc_Svc64:
{
exception = ams::svc::DebugException_UndefinedSystemCall;
param2 = far;
param3 = (esr & 0xFF);
}
break;
case EsrEc_SErrorInterrupt:
{
exception = ams::svc::DebugException_MemorySystemError;
param2 = far;
}
break;
case EsrEc_InstructionAbortEl0:
{
exception = ams::svc::DebugException_InstructionAbort;
param2 = far;
}
break;
case EsrEc_DataAbortEl0:
default:
{
exception = ams::svc::DebugException_DataAbort;
param2 = far;
}
break;
}
/* Process the debug event. */
Result result = KDebug::OnDebugEvent(ams::svc::DebugEvent_Exception, exception, param2, param3);
/* If the SVC is handled, handle it. */
if (!svc::ResultNotHandled::Includes(result)) {
/* If we should stop processing the exception, restore. */
if (svc::ResultStopProcessingException::Includes(result)) {
svc::RestoreContext(reinterpret_cast<uintptr_t>(e_ctx));
}
/* If we successfully enter jit debug, restore. */
if (cur_process.EnterJitDebug(ams::svc::DebugEvent_Exception, exception, param2, param3)) {
svc::RestoreContext(reinterpret_cast<uintptr_t>(e_ctx));
}
}
/* Otherwise, if result debug was returned, restore. */
if (svc::ResultDebug::Includes(result)) {
svc::RestoreContext(reinterpret_cast<uintptr_t>(e_ctx));
}
}
}
/* Print that an exception occurred. */
MESOSPHERE_RELEASE_LOG("Exception occurred. %016lx\n", GetCurrentProcess().GetProgramId());
/* Exit the current process. */
GetCurrentProcess().Exit();
}
/* NOTE: This function is called from ASM. */
void HandleException(KExceptionContext *context) {
MESOSPHERE_ASSERT(!KInterruptManager::AreInterruptsEnabled());
@ -112,14 +470,14 @@ namespace ams::kern::arch::arm64 {
/* Collect far and data based on the ec. */
switch ((esr >> 26) & 0x3F) {
case 0x0: /* Unknown */
case 0xE: /* Illegal Execution State */
case 0x38: /* BKPT instruction */
case 0x3C: /* BRK instruction */
case EsrEc_Unknown:
case EsrEc_IllegalExecution:
case EsrEc_BkptInstruction:
case EsrEc_BrkInstruction:
far = context->pc;
data = GetInstructionData(context, esr);
break;
case 0x11: /* SVC instruction from Aarch32 */
case EsrEc_Svc32:
if (context->psr & 0x20) {
/* Thumb mode. */
context->pc -= 2;
@ -129,11 +487,11 @@ namespace ams::kern::arch::arm64 {
}
far = context->pc;
break;
case 0x15: /* SVC instruction from Aarch64 */
case EsrEc_Svc64:
context->pc -= 4;
far = context->pc;
break;
case 0x30: /* Breakpoint from lower EL */
case EsrEc_BreakPointEl0:
far = context->pc;
break;
default:
@ -143,6 +501,8 @@ namespace ams::kern::arch::arm64 {
/* Note that we're in an exception handler. */
GetCurrentThread().SetInExceptionHandler();
/* Verify that spsr's M is allowable (EL0t). */
{
const bool is_user_mode = (context->psr & 0xF) == 0;
if (is_user_mode) {