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kern: split out GetInstructionDataUserMode in exception handler

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Michael Scire 2023-10-11 09:51:40 -07:00 committed by SciresM
parent 3737151a2f
commit 4ddfb6183c
1 changed files with 44 additions and 6 deletions
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44
libraries/libmesosphere/source/arch/arm64/kern_exception_handlers.cpp
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@ -59,7 +59,9 @@ namespace ams::kern::arch::arm64 {
EsrEc_BrkInstruction = 0b111100,
};
constexpr u32 GetInstructionData(const KExceptionContext *context, u64 esr) {
u32 GetInstructionDataSupervisorMode(const KExceptionContext *context, u64 esr) {
/* Check for THUMB usermode */
if ((context->psr & 0x3F) == 0x30) {
u32 insn = *reinterpret_cast<u16 *>(context->pc & ~0x1);
@ -74,6 +76,37 @@ namespace ams::kern::arch::arm64 {
}
}
u32 GetInstructionDataUserMode(const KExceptionContext *context) {
/* Check for THUMB usermode */
u32 insn = 0;
if ((context->psr & 0x3F) == 0x30) {
u16 insn_high = 0;
if (UserspaceAccess::CopyMemoryFromUser(std::addressof(insn_high), reinterpret_cast<u16 *>(context->pc & ~0x1), sizeof(insn_high))) {
insn = insn_high;
/* Check if the instruction was a THUMB mode branch prefix. */
if (((insn >> 11) & 0b11110) == 0b11110) {
u16 insn_low = 0;
if (UserspaceAccess::CopyMemoryFromUser(std::addressof(insn_low), reinterpret_cast<u16 *>((context->pc & ~0x1) + sizeof(u16)), sizeof(insn_low))) {
insn = (static_cast<u32>(insn_high) << 16) | (static_cast<u32>(insn_low) << 0);
} else {
insn = 0;
}
}
} else {
insn = 0;
}
} else {
u32 insn_value = 0;
if (UserspaceAccess::CopyMemoryFromUser(std::addressof(insn_value), reinterpret_cast<u32 *>(context->pc), sizeof(insn_value))) {
insn = insn_value;
} else {
insn = 0;
}
}
return insn;
}
void HandleUserException(KExceptionContext *context, u64 esr, u64 far, u64 afsr0, u64 afsr1, u32 data) {
KProcess &cur_process = GetCurrentProcess();
bool should_process_user_exception = KTargetSystem::IsUserExceptionHandlersEnabled();
@ -501,6 +534,7 @@ namespace ams::kern::arch::arm64 {
MESOSPHERE_ASSERT(!KInterruptManager::AreInterruptsEnabled());
/* Retrieve information about the exception. */
const bool is_user_mode = (context->psr & 0xF) == 0;
const u64 esr = cpu::GetEsrEl1();
const u64 afsr0 = cpu::GetAfsr0El1();
const u64 afsr1 = cpu::GetAfsr1El1();
@ -514,7 +548,12 @@ namespace ams::kern::arch::arm64 {
case EsrEc_BkptInstruction:
case EsrEc_BrkInstruction:
far = context->pc;
data = GetInstructionData(context, esr);
/* NOTE: Nintendo always calls GetInstructionDataUserMode. */
if (is_user_mode) {
data = GetInstructionDataUserMode(context);
} else {
data = GetInstructionDataSupervisorMode(context, esr);
}
break;
case EsrEc_Svc32:
if (context->psr & 0x20) {
@ -543,7 +582,6 @@ namespace ams::kern::arch::arm64 {
/* Verify that spsr's M is allowable (EL0t). */
{
const bool is_user_mode = (context->psr & 0xF) == 0;
if (is_user_mode) {
/* If the user disable count is set, we may need to pin the current thread. */
if (GetCurrentThread().GetUserDisableCount() != 0 && GetCurrentProcess().GetPinnedThread(GetCurrentCoreId()) == nullptr) {