SVC
System calls
Id | Name | In | Out |
---|---|---|---|
0x1 | #svcSetHeapSize | W1=size | W0=result, X1=outaddr |
0x2 | #svcSetMemoryPermission | X0=addr, X1=size, W2=prot | W0=result |
0x3 | #svcSetMemoryAttribute | X0=addr, X1=size, W2=state0, W3=state1 | W0=result |
0x4 | #svcMapMemory | X0=dstaddr, X1=srcaddr, X2=size | W0=result |
0x5 | #svcUnmapMemory | X0=dstaddr, X1=srcaddr, X2=size | W0=result |
0x6 | #svcQueryMemory | X0=MemoryInfo*, X2=addr | W0=result, W1=PageInfo |
0x7 | #svcExitProcess | None | |
0x8 | #svcCreateThread | X1=entry, X2=thread_context, X3=stacktop, W4=prio, W5=processor_id | W0=result, W1=handle |
0x9 | #svcStartThread | W0=thread_handle | W0=result |
0xA | #svcExitThread | None | |
0xB | #svcSleepThread | X0=nano | W0=result |
0xC | #svcGetThreadPriority | W1=thread_handle | W0=result, W1=prio |
0xD | #svcSetThreadPriority | W0=thread_handle, W1=prio | W0=result |
0xE | #svcGetThreadCoreMask | W2=thread_handle | W0=result, W1=out, X2=out |
0xF | #svcSetThreadCoreMask | W0=thread_handle, W1=in, X2=in2 | W0=result |
0x10 | #svcGetCurrentProcessorNumber | None | W0/X0=cpuid |
0x11 | svcSignalEvent | W0=wevent_handle | W0=result |
0x12 | svcClearEvent | W0=wevent_or_revent_handle | W0=result |
0x13 | #svcMapSharedMemory | W0=shmem_handle, X1=addr, X2=size, W3=perm | W0=result |
0x14 | svcUnmapSharedMemory | W0=shmem_handle, X1=addr, X2=size | W0=result |
0x15 | #svcCreateTransferMemory | X1=addr, X2=size, W3=perm | W0=result, W1=tmem_handle |
0x16 | svcCloseHandle | W0=handle | W0=result |
0x17 | svcResetSignal | W0=revent_or_process_handle | W0=result |
0x18 | #svcWaitSynchronization | X1=handles_ptr, W2=num_handles. X3=timeout | W0=result, W1=handle_idx |
0x19 | svcCancelSynchronization | W0=thread_handle | W0=result |
0x1A | svcArbitrateLock | W0=cur_thread_handle, X1=ptr, W2=req_thread_handle | |
0x1B | svcArbitrateUnlock | X0=ptr | |
0x1C | svcWaitProcessWideKeyAtomic | X0=ptr0, X1=ptr, W2=thread_handle, X3=timeout | W0=result |
0x1D | svcSignalProcessWideKey | X0=ptr, W1=value | W0=result |
0x1E | svcGetSystemTick | None | X0={value of cntpct_el0} |
0x1F | svcConnectToNamedPort | X1=port_name_str | W0=result, W1=handle |
0x20 | svcSendSyncRequestLight | W0=light_session_handle, X1=? | W0=result |
0x21 | svcSendSyncRequest | X0=normal_session_handle | W0=result |
0x22 | #svcSendSyncRequestWithUserBuffer | X0=cmdbufptr, X1=size, X2=handle | W0=result |
0x23 | svcSendAsyncRequestWithUserBuffer | X1=cmdbufptr, X2=size, X3=handle | W0=result, W1=event_handle |
0x24 | svcGetProcessId | W1=thread_or_process_or_debug_handle | W0=result, X1=pid |
0x25 | svcGetThreadId | W0=thread_handle | W0=result, X1=out |
0x26 | #svcBreak | X0=break_reason,X1,X2=info | ? |
0x27 | svcOutputDebugString | X0=str, X1=size | W0=result |
0x28 | svcReturnFromException | X0=result | |
0x29 | #svcGetInfo | X1=info_id, X2=handle, X3=info_sub_id | W0=result, X1=out |
0x2A | svcFlushEntireDataCache | None | None |
0x2B | svcFlushDataCache | X0=addr, X1=size | W0=result |
0x2C | [3.0.0+] #svcMapPhysicalMemory | X0=addr, X1=size | W0=result |
0x2D | [3.0.0+] svcUnmapPhysicalMemory | X0=addr, X1=size | W0=result |
0x2F | svcGetLastThreadInfo | None | W0=result, W1,W2,W3,W4=unk, W5=truncated_u64, W6=bool |
0x30 | svcGetResourceLimitLimitValue | W1=reslimit_handle, W2=#LimitableResource | W0=result, X1=value |
0x31 | svcGetResourceLimitCurrentValue | W1=reslimit_handle, W2=#LimitableResource | W0=result, X1=value |
0x32 | svcSetThreadActivity | W0=thread_handle, W1=bool | W0=result |
0x33 | svcGetThreadContext3 | W0=thread_handle, W1=#ThreadContext* | W0=result |
0x34 | [4.0.0+] | X0=ptr, W1=type, X2=? X3=timeout | |
0x35 | [4.0.0+] | X0=ptr, W1=type, X2=? W3=? | |
0x3C | #svcDumpInfo | ||
0x3D | [4.0.0+] svcDumpInfoNew | ||
0x40 | svcCreateSession | W2=is_light, X3=? | W0=result, W1=server_handle, W2=client_handle |
0x41 | #svcAcceptSession | W1=port_handle | W0=result, W1=session_handle |
0x42 | svcReplyAndReceiveLight | W0=light_session_handle | W0=result, W1,W2,W3,W4,W5,W6,W7=out |
0x43 | #svcReplyAndReceive | X1=ptr_handles, W2=num_handles, X3=replytarget_handle(0=none), X4=timeout | W0=result, W1=handle_idx |
0x44 | svcReplyAndReceiveWithUserBuffer | X1=buf, X2=sz, X3=ptr_handles, W4=num_handles, X5=replytarget_handle(0=none), X6=timeout | W0=result, W1=handle_idx |
0x45 | svcCreateEvent | None | W0=result, W1=client_handle ?, W2=server_handle ? |
0x4B | [4.0.0+] #svcCreateJitMemory | X1=addr, X2=size | W0=result, W1=jit_handle |
0x4C | [4.0.0+] #svcMapJitMemory | W0=jit_handle, W1=#MapJitOperation, X2=dstaddr, X3=size, W4=perm | W0=result |
0x4D | svcSleepSystem | None | None |
0x4E | #svcReadWriteRegister | X1=reg_addr, W2=rw_mask, W3=in_val | W0=result, W1=out_val |
0x4F | svcSetProcessActivity | W0=process_handle, W1=bool | W0=result |
0x50 | #svcCreateSharedMemory | W1=size, W2=myperm, W3=otherperm | W0=result, W1=shmem_handle |
0x51 | #svcMapTransferMemory | X0=tmem_handle, X1=addr, X2=size, W3=perm | W0=result |
0x52 | #svcUnmapTransferMemory | W0=tmemhandle, X1=addr, X2=size | W0=result |
0x53 | svcCreateInterruptEvent | X1=irq_num, W2=flag | W0=result, W1=handle |
0x54 | #svcQueryPhysicalAddress | X1=addr | W0=result, X1=physaddr, X2=kerneladdr, X3=size |
0x55 | #svcQueryIoMapping | X1=physaddr, X2=size | W0=result, X1=virtaddr |
0x56 | #svcCreateDeviceAddressSpace | X1=dev_as_start_addr, X2=dev_as_end_addr | W0=result, W1=dev_as_handle |
0x57 | #svcAttachDeviceAddressSpace | W0=device, X1=dev_as_handle | W0=result |
0x58 | #svcDetachDeviceAddressSpace | W0=device, X1=dev_as_handle | W0=result |
0x59 | #svcMapDeviceAddressSpaceByForce | W0=dev_as_handle, W1=proc_handle, X2=dev_map_addr, X3=dev_as_size, X4=dev_as_addr, W5=perm | W0=result |
0x5A | #svcMapDeviceAddressSpaceAligned | W0=dev_as_handle, W1=proc_handle, X2=dev_map_addr, X3=dev_as_size, X4=dev_as_addr, W5=perm | W0=result |
0x5B | svcMapDeviceAddressSpace | ||
0x5C | #svcUnmapDeviceAddressSpace | W0=dev_as_handle, W1=proc_handle, X2=dev_map_addr, X3=dev_as_size, X4=dev_as_addr | W0=result |
0x5D | svcInvalidateProcessDataCache | W0=process_handle, X1=addr, X2=size | W0=size |
0x5E | svcStoreProcessDataCache | W0=process_handle, X1=addr, X2=size | W0=size |
0x5F | svcFlushProcessDataCache | W0=process_handle, X1=addr, X2=size | W0=size |
0x60 | svcDebugActiveProcess | X1=pid | W0=result, W1=debug_handle |
0x61 | svcBreakDebugProcess | W0=debug_handle | W0=result |
0x62 | svcTerminateDebugProcess | W0=debug_handle | W0=result |
0x63 | svcGetDebugEvent | X0=DebugEventInfo*, W1=debug_handle | W0=result |
0x64 | svcContinueDebugEvent | W0=debug_handle, W1=#ContinueDebugFlags, X2=thread_id | W0=result |
0x65 | svcGetProcessList | X1=pids_out_ptr, W2=max_out | W0=result, W1=num_out |
0x66 | svcGetThreadList | X1=tids_out_ptr, W2=max_out, W3=debug_handle_or_zero | W0=result, X1=num_out |
0x67 | svcGetDebugThreadContext | X0=ThreadContext*, X1=debug_handle, X2=thread_id, W3=#ThreadContextFlags | W0=result |
0x68 | svcSetDebugThreadContext | W0=debug_handle, W1=#ThreadContextFlags, X2=ThreadContext* | W0=result |
0x69 | svcQueryDebugProcessMemory | X0=#MemoryInfo*, X2=debug_handle, X3=addr | W0=result, W1=PageInfo |
0x6A | svcReadDebugProcessMemory | X0=buffer*, X1=debug_handle, X2=src_addr, X3=size | W0=result |
0x6B | svcWriteDebugProcessMemory | X0=debug_handle, X1=buffer*, X2=dst_addr, X3=size | W0=result |
0x6C | svcSetHardwareBreakPoint | W0=HardwareBreakpointId, X1=watchpoint_flags, X2=watchpoint_value/debug_handle? | |
0x6D | svcGetDebugThreadParam | X2=debug_handle, X3=thread_id, W4=#DebugThreadParam | W0=result, X1=out0, W2=out1 |
0x70 | svcCreatePort | W2=max_sessions, W3=unk_bool, X4=name_ptr | W0=result, W1=clientport_handle, W2=serverport_handle |
0x71 | svcManageNamedPort | X1=name_ptr, W2=max_sessions | W0=result, W1=serverport_handle |
0x72 | svcConnectToPort | W1=clientport_handle | W0=result, W1=session_handle |
0x73 | #svcSetProcessMemoryPermission | W0=process_handle, X1=addr, X2=size, W3=perm | W0=result |
0x74 | #svcMapProcessMemory | X0=srcaddr, W1=process_handle, X2=dstaddr, X3=size | W0=result |
0x75 | #svcUnmapProcessMemory | W0=process_handle, X1=dstaddr, X2=srcaddr, X3=size | W0=result |
0x76 | #svcQueryProcessMemory | X0=meminfo_ptr, W2=process_handle, X3=addr | W0=result, W1=pageinfo |
0x77 | #svcMapProcessCodeMemory | W0=process_handle, X2=dstaddr, X2=srcaddr, X3=size | W0=result |
0x78 | #svcUnmapProcessCodeMemory | W0=process_handle, X1=dstaddr, X2=srcaddr, X3=size | W0=result |
0x79 | #svcCreateProcess | X1=procinfo_ptr, X2=caps_ptr, W3=cap_num | W0=result, W1=process_handle |
0x7A | svcStartProcess | W0=process_handle, W1=main_thread_prio, W2=default_cpuid, W3=main_thread_stacksz | W0=result |
0x7B | svcTerminateProcess | W0=process_handle | W0=result |
0x7C | #svcGetProcessInfo | W0=process_handle | W0=result, X1=#ProcessState |
0x7D | svcCreateResourceLimit | None | W0=result, W1=reslimit_handle |
0x7E | svcSetResourceLimitLimitValue | W0=reslimit_handle, W1=#LimitableResource, X2=value | W0=result |
0x7F | svcCallSecureMonitor | X0=smc_sub_id, X1,X2,X3,X4,X5,X6,X7=smc_args | X0,X1,X2,X3,X4,X5,X6,X7=result |
svcSetHeapSize
Argument | Type | Name |
---|---|---|
(In) W1 | u64 | Size |
(Out) W0 | #Result | Ret |
(Out) X1 | u64 | OutAddr |
Description: Set the process heap to a given Size. It can both extend and shrink the heap.
Size must be a multiple of 0x200000.
On success, the heap base-address (which is fixed by kernel, aslr'd) is written to OutAddr.
[2.0.0+] Size must be less than 0x18000000.
svcSetMemoryPermission
Argument | Type | Name |
---|---|---|
(In) X0 | void* | Addr |
(In) X1 | u64 | Size |
(In) W2 | #Permission | Prot |
(Out) W0 | #Result | Ret |
Description: Change permission of page-aligned memory region.
Bit2 of permission (exec) is not allowed. Setting write-only is not allowed either (bit1).
This can be used to move back and forth between ---, r-- and rw-.
svcSetMemoryAttribute
Argument | Type | Name |
---|---|---|
(In) X0 | void* | Addr |
(In) X1 | u64 | Size |
(In) W2 | u32 | State0 |
(In) W3 | u32 | State1 |
(Out) W0 | #Result | Ret |
Description: Change attribute of page-aligned memory region.
This is used to turn on/off caching for a given memory area. Useful when talking to devices such as the GPU.
What happens "under the hood" is the "Memory Attribute Indirection Register" index is changed from 2 to 3 in the MMU descriptor.
State0 | State1 | Action |
---|---|---|
0 | 0 | Clear bit3 in #MemoryAttribute. |
8 | 0 | Clear bit3 in #MemoryAttribute. |
8 | 8 | Set bit3 in #MemoryAttribute. |
svcMapMemory
Argument | Type | Name |
---|---|---|
(In) X0 | void* | DstAddr |
(In) X1 | void* | SrcAddr |
(In) X2 | u64 | Size |
(Out) W0 | #Result | Ret |
Description: Maps a memory range into a different range.
Mainly used for adding guard pages around stack.
Source range gets reprotected to --- (it can no longer be accessed), and bit0 is set in the source #MemoryAttribute.
If dstaddr >= LowerTreshold, the dst-range is enforced to be within the process' "MapRegion". Code can get the range of this region from #svcGetInfo id0=2,3.
In this case, the mapped memory will have state 0x5C3C0B.
As long as (dstaddr+size) < LowerThreshold, then you can map anywhere but the mapped memory will have state 0x482907 instead.
LowerTreshold is 0x80000000 for 36-bit address spaces, and 0x40000000 for 32-bit ones.
[2.0.0+] Support for the 0x482907 mappings outside the "MapRegion" were removed.
svcUnmapMemory
Argument | Type | Name |
---|---|---|
(In) X0 | void* | DstAddr |
(In) X1 | void* | SrcAddr |
(In) X2 | u64 | Size |
(Out) W0 | #Result | Ret |
Description: Unmaps a region that was previously mapped with #svcMapMemory.
It's possible to unmap ranges partially, you don't need to unmap the entire range "in one go".
The srcaddr/dstaddr must match what was given when the pages were originally mapped.
svcQueryMemory
Argument | Type | Name |
---|---|---|
(In) X0 | #MemoryInfo* | MemInfo |
(In) X2 | void* | Addr |
(Out) W0 | #Result | Ret |
(Out) W1 | PageInfo | PageInfo |
Description: Query information about an address. Will always fetch the lowest page-aligned mapping that contains the provided address.
Outputs a #MemoryInfo struct.
svcExitProcess
Argument | Type | Name |
---|---|---|
(In) None | ||
(Out) None |
Description: Exits the current process.
svcCreateThread
Argument | Type | Name |
---|---|---|
(In) X1 | void(*)(void*) | Entry |
(In) X2 | void* | ThreadContext |
(In) X3 | void* | StackTop |
(In) W4 | u32 | Priority |
(In) W5 | u32 | ProcessorId |
(Out) W0 | #Result | Ret |
(Out) W1 | Handle<Thread> | Handle |
Description: Create a thread in the current process.
Processor_id must be 0,1,2,3 or -2, where -2 uses the default cpuid for process.
svcStartThread
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<Thread> | Handle |
(Out) None |
Description: Starts the thread for the provided handle.
svcExitThread
Argument | Type | Name |
---|---|---|
(In) None | ||
(Out) None |
Description: Exits the current thread.
svcSleepThread
Argument | Type | Name |
---|---|---|
(In) X0 | u64 | Nano |
(Out) W0 | #Result | Ret |
Description: Sleep for a specified amount of time, or yield thread.
Setting nano=0 means "yield thread".
svcGetThreadPriority
Argument | Type | Name |
---|---|---|
(In) W1 | Handle<Thread> | Handle |
(Out) W0 | #Result | Ret |
(Out) W1 | u64 | Priority |
Description: Get priority of provided thread handle.
svcSetThreadPriority
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<Thread> | Handle |
(In) W1 | u32 | Priority |
(Out) W0 | #Result | Ret |
Description: Set priority of provided thread handle.
Priority is a number 0-0x3F. Lower value means higher priority.
svcGetThreadCoreMask
Argument | Type | Name |
---|---|---|
(In) W2 | Handle<Thread> | Handle |
(Out) W0 | #Result | Ret |
(Out) W1 | u32 | Out0 |
(Out) X2 | u64 | Out1 |
Description: Get affinity mask of provided thread handle.
svcSetThreadCoreMask
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<Thread> | Handle |
(In) W1 | u32 | In0 |
(In) X2 | u64 | In1 |
(Out) W0 | #Result | Ret |
Description: Set affinity mask of provided thread handle.
svcGetCurrentProcessorNumber
Argument | Type | Name |
---|---|---|
(In) None | ||
(Out) W0/X0 | u64 | CpuId |
Description: Get which cpu is executing the current thread.
Cpu-id is an integer in the range 0-3.
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<SharedMemory> | MemHandle |
(In) X1 | void* | Addr |
(In) X2 | u64 | Size |
(In) W3 | #Permission | Permissions |
(Out) W0 | #Result | Ret |
Maps the block supplied by the handle. The required permissions are different for the process that created the handle and all other processes.
Increases reference count for the KSharedMemory object. Thus in order to release the memory associated with the object, all handles to it must be closed and all mappings must be unmapped.
svcCreateTransferMemory
Argument | Type | Name |
---|---|---|
(In) X1 | void* | Addr |
(In) X2 | u64 | Size |
(In) W3 | #Permission | Permissions |
(Out) W0 | #Result | Ret |
(Out) W1 | Handle<TransferMemory> | Handle |
This one reprotects the src block with perms you give it. It also sets bit0 into #MemoryAttribute.
Executable bit perm not allowed.
Closing all handles automatically causes the bit0 in #MemoryAttribute to clear, and the permission to reset.
svcWaitSynchronization
Argument | Type | Name |
---|---|---|
(In) X1 | Handle* | HandlesPtr |
(In) W2 | u64 | HandlesNum |
(In) X3 | u64 | Timeout |
(Out) W0 | #Result | Ret |
(Out) W1 | u64 | HandleIndex |
Works with num_handles <= 0x40, error on num_handles == 0.
Does not accept 0xFFFF8001 or 0xFFFF8000 as handles.
Object types
Port: signals when there is an incoming connection waiting to be accepted.
Session (server-side): signals when there is an incoming message waiting to be received or the pipe is closed.
Result codes
0x0: Success. One of the objects was signalled before the timeout expired. Handle index is updated to indicate which object signalled.
0xe401: Invalid handle. Returned when one of the handles passed is invalid. Handle index is not updated.
0xea01: Timeout. Returned when no objects have been signalled within the timeout. Handle index is not updated.
svcSendSyncRequestWithUserBuffer
Argument | Type | Name |
---|---|---|
(In) X0 | void* | CmdPtr |
(In) X1 | u64 | Size |
(In) W2 | Handle<Session> | Handle |
(Out) W0 | #Result | Ret |
Size must be 0x1000-aligned.
svcBreak
Argument | Type | Name |
---|---|---|
(In) X0 | u64 | Break Reason |
(In) X1 | u64 | |
(In) X2 | u64 | Info |
(Out)Â ? | ? | ? |
When used on retail where inx0 bit31 is clear, the system will throw a fatal-error. Otherwise when bit31 is set, it will return 0 and notify the debugger?
svcGetInfo
Argument | Type | Name |
---|---|---|
(In) X1 | u64 | InfoId |
(In) W2 | Handle | Handle |
(In) X3 | u64 | InfoSubId |
(Out) W0 | #Result | Ret |
(Out) X1 | u64 | Out |
Handle type | Id0 | Id1 | Description |
---|---|---|---|
Process | 0 | 0 | AllowedCpuIdBitmask |
Process | 1 | 0 | AllowedThreadPrioBitmask |
Process | 2 | 0 | MapRegionBaseAddr |
Process | 3 | 0 | MapRegionSize |
Process | 4 | 0 | HeapRegionBaseAddr |
Process | 5 | 0 | HeapRegionSize |
Process | 6 | 0 | TotalMemoryAvailable. Total memory available(free+used). |
Process | 7 | 0 | TotalMemoryUsage. Total used size of codebin memory + main-thread stack + allocated heap. |
Zero | 8 | 0 | IsCurrentProcessBeingDebugged |
Zero | 9 | 0 | Returns ResourceLimit handle for current process. Used by PM. |
Zero | 10 | -1, {current coreid} | IdleTickCount |
Zero | 11 | 0-3 | RandomEntropy from current process. TRNG. Used to seed usermode PRNGs. |
Process | 12 | 0 | [2.0.0+] AddressSpaceBaseAddr |
Process | 13 | 0 | [2.0.0+] AddressSpaceSize |
Process | 14 | 0 | [2.0.0+] NewMapRegionBaseAddr |
Process | 15 | 0 | [2.0.0+] NewMapRegionSize |
Process | 16 | 0 | [3.0.0+] IsVirtualAddressMemoryEnabled |
Process | 17 | 0 | [3.0.0+] Some size in bytes. |
Process | 18 | 0 | [3.0.0+] TitleId |
Zero | 19 | 0 | [4.0.0+] PrivilegedProcessId_LowerBound |
Zero | 19 | 1 | [4.0.0+] PrivilegedProcessId_UpperBound |
Thread | 0xF0000002 | 0 | Performance counter related. |
svcMapPhysicalMemory
This is like svcSetHeapSize except you can allocate heap at any address you'd like.
svcDumpInfo
Argument | Type | Name |
---|---|---|
(In) None | ||
(Out) None |
Does nothing, just returns with registers set to all-zero.
svcAcceptSession
Argument | Type | Name |
---|---|---|
(In) W1 | Handle<Port> | Port |
(Out) W0 | #Result | Result |
(Out) W1 | Handle<ServerSession> | Session |
Result codes
0xf201: No session waiting to be accepted
svcReplyAndReceive
Argument | Type | Name |
---|---|---|
(In) W1 | *Handle<Port or ServerSession> | Handles |
(In) W2 | u32 | NumHandles |
(In) W3 | Handle<ServerSession> | ReplyTarget |
(In) X4 | u64 (nanoseconds) | Timeout |
(Out) W0 | #Result | Result |
(Out) W1 | u32 | HandleIndex |
If ReplyTarget is not zero, a reply from the TLS will be sent to that session. Then it will wait until either of the passed sessions has an incoming message, is closed, a passed port has an incoming connection, or the timeout expires. If there is an incoming message, it is copied to the TLS.
After being validated, passed handles will be enumerated in order; even if a session has been closed, if one that appears earlier in the list has an incoming message, it will take priority and a result code of 0x0 will be returned.
Result codes
0x0: Success. Either a session has an incoming message or a port has an incoming connection. HandleIndex is set appropriately.
0xea01: Timeout. No handles were signalled before the timeout expired. HandleIndex is not updated.
0xf601: Port remote dead. One of the sessions has been closed. HandleIndex is set appropriately.
svcCreateJitMemory
Takes an address range with backing memory to create the JIT memory object.
The memory is initially memset to 0xFF after being locked.
svcMapJitMemory
Maps the backing memory for a JIT memory object into the current process.
For MapJitOperation_MapOwner, memory permission must be RW-.
For MapJitOperation_MapSlave, memory permission must be R-- or R-X.
Operations MapJitOperation_UnmapOwner/MapJitOperation_UnmapSlave unmap memory that was previously mapped this way.
This allows one "secure JIT" process to map the memory as RW-, and the other "slave" process to map it R-X.
svcReadWriteRegister
Argument | Type | Name |
---|---|---|
(In) X1 | u64 | RegAddr |
(In) W2 | u64 | RwMask |
(In) W3 | u64 | InValue |
(Out) W0 | #Result | Ret |
(Out) W1 | u64 | OutValue |
Read/write IO registers with a hardcoded whitelist. Input address is physical-address and must be aligned to 4.
rw_mask is 0 for reading and 0xffffffff for writing. You can also write individual bits by using a mask value.
You can only write to registers inside physical pages 0x70019000 (MC), 0x7001C000 (MC0), 0x7001D000 (MC1), and they all share the same whitelist.
The whitelist is same for writing as for reading.
The whitelist is:
0x054, 0x090, 0x094, 0x098, 0x09c, 0x0a0, 0x0a4, 0x0a8, 0x0ac, 0x0b0, 0x0b4, 0x0b8, 0x0bc, 0x0c0, 0x0c4, 0x0c8, 0x0d0, 0x0d4, 0x0d8, 0x0dc, 0x0e0, 0x100, 0x108, 0x10c, 0x118, 0x11c, 0x124, 0x128, 0x12c, 0x130, 0x134, 0x138, 0x13c, 0x158, 0x15c, 0x164, 0x168, 0x16c, 0x170, 0x174, 0x178, 0x17c, 0x200, 0x204, 0x2e4, 0x2e8, 0x2ec, 0x2f4, 0x2f8, 0x310, 0x314, 0x320, 0x328, 0x344, 0x348, 0x370, 0x374, 0x37c, 0x380, 0x390, 0x394, 0x398, 0x3ac, 0x3b8, 0x3bc, 0x3c0, 0x3c4, 0x3d8, 0x3e8, 0x41c, 0x420, 0x424, 0x428, 0x42c, 0x430, 0x44c, 0x47c, 0x480, 0x484, 0x50c, 0x554, 0x558, 0x55c, 0x670, 0x674, 0x690, 0x694, 0x698, 0x69c, 0x6a0, 0x6a4, 0x6c0, 0x6c4, 0x6f0, 0x6f4, 0x960, 0x970, 0x974, 0xa20, 0xa24, 0xb88, 0xb8c, 0xbc4, 0xbc8, 0xbcc, 0xbd0, 0xbd4, 0xbd8, 0xbdc, 0xbe0, 0xbe4, 0xbe8, 0xbec, 0xc00, 0xc5c, 0xcac
[2.0.0+] Whitelist was extended with 0x4c4, 0x4c8, 0x4cc, 0x584, 0x588, 0x58c.
[2.0.0+] The IO registers in range 0x7000E400 (PMC) size 0xC00 skip the whitelist, and do a TrustZone call using SMC Id1 0xC3000008(ReadWriteRegister).
[4.0.0+] Access to the Memory Controller (0x70019000) also uses smcReadWriteRegister.
Here is the whitelist imposed by that SMC, relative to the start of the PMC registers:
0x000, 0x00c, 0x010, 0x014, 0x01c, 0x020, 0x02c, 0x030, 0x034, 0x038, 0x03c, 0x040, 0x044, 0x048, 0x0dc, 0x0e0, 0x0e4, 0x160, 0x164, 0x168, 0x170, 0x1a8, 0x1b8, 0x1bc, 0x1c0, 0x1c4, 0x1c8, 0x2b4, 0x2d4, 0x440, 0x4d8
Here is the whitelist imposed by smcReadWriteRegister (checked in addition to the whitelist in svcReadWriteRegister), relative to the start of the MC registers:
0x000, 0x004, 0x008, 0x00C, 0x010, 0x01C, 0x020, 0x030, 0x034, 0x050, 0x054, 0x090, 0x094, 0x098, 0x09C, 0x0A0, 0x0A4, 0x0A8, 0x0AC, 0x0B0, 0x0B4, 0x0B8, 0x0BC, 0x0C0, 0x0C4, 0x0C8, 0x0D0, 0x0D4, 0x0D8, 0x0DC, 0x0E0, 0x100, 0x108, 0x10C, 0x118, 0x11C, 0x124, 0x128, 0x12C, 0x130, 0x134, 0x138, 0x13C, 0x158, 0x15C, 0x164, 0x168, 0x16C, 0x170, 0x174, 0x178, 0x17C, 0x200, 0x204, 0x238, 0x240, 0x244, 0x250, 0x254, 0x258, 0x264, 0x268, 0x26C, 0x270, 0x274, 0x280, 0x284, 0x288, 0x28C, 0x294, 0x2E4, 0x2E8, 0x2EC, 0x2F4, 0x2F8, 0x310, 0x314, 0x320, 0x328, 0x344, 0x348, 0x370, 0x374, 0x37C, 0x380, 0x390, 0x394, 0x398, 0x3AC, 0x3B8, 0x3BC, 0x3C0, 0x3C4, 0x3D8, 0x3E8, 0x41C, 0x420, 0x424, 0x428, 0x42C, 0x430, 0x44C, 0x47C, 0x480, 0x484, 0x4C4, 0x4C8, 0x4CC, 0x50C, 0x554, 0x558, 0x55C, 0x584, 0x588, 0x58C, 0x670, 0x674, 0x690, 0x694, 0x698, 0x69C, 0x6A0, 0x6A4, 0x6C0, 0x6C4, 0x6F0, 0x6F4, 0x960, 0x970, 0x974, 0x9B8, 0xA20, 0xA24, 0xA88, 0xA94, 0xA98, 0xA9C, 0xAA0, 0xAA4, 0xAA8, 0xAAC, 0xAB0, 0xAB4, 0xAB8, 0xABC, 0xAC0, 0xAC4, 0xAC8, 0xACC, 0xAD0, 0xAD4, 0xAD8, 0xADC, 0xAE0, 0xB88, 0xB8C, 0xBC4, 0xBC8, 0xBCC, 0xBD0, 0xBD4, 0xBD8, 0xBDC, 0xBE0, 0xBE4, 0xBE8, 0xBEC, 0xC00, 0xC5C, 0xCAC
Argument | Type | Name |
---|---|---|
(In) W1 | u64 | Size |
(In) W2 | #Permission | LocalPerm |
(In) W3 | #Permission | RemotePerm |
(Out) W0 | #Result | Ret |
(Out) W1 | Handle<SharedMemory> | MemHandle |
Other perm can be used to enforce permission 1, 3, or 0x10000000 if don't care.
svcMapTransferMemory
Argument | Type | Name |
---|---|---|
(In) X0 | Handle<TransferMemory> | MemHandle |
(In) X1 | void* | Addr |
(In) X2 | u64 | Size |
(In) W3 | #Permission | Permissions |
(Out) W0 | #Result | Ret |
The newly mapped pages will have #MemoryState type 0xE.
You must pass same size and permissions as given in svcCreateMemoryMirror, otherwise error.
svcUnmapTransferMemory
Argument | Type | Name |
---|---|---|
(In) X0 | Handle<TransferMemory> | MemHandle |
(In) X1 | void* | Addr |
(In) X2 | u64 | Size |
(Out) W0 | #Result | Ret |
Size must match size given in map syscall, otherwise there's an invalid-size error.
svcQueryPhysicalAddress
Argument | Type | Name |
---|---|---|
(In) X1 | u64 | Addr |
(Out) W0 | #Result | Ret |
(Out) X1 | u64 | PhysAddr |
(Out) X2 | u64 | KernelAddr |
(Out) X3 | u64 | Size |
svcQueryIoMapping
Argument | Type | Name |
---|---|---|
(In) X1 | u64 | PhysAddr |
(In) X2 | u64 | Size |
(Out) W0 | #Result | Ret |
(Out) X1 | void* | VirtAddr |
Description: Returns a virtual address mapped to a given IO range.
svcCreateDeviceAddressSpace
Argument | Type | Name |
---|---|---|
(In) X1 | u64 | StartAddr |
(In) X2 | u64 | EndAddr |
(Out) W0 | #Result | Ret |
(Out) W1 | Handle<DeviceAddressSpace> | AddressSpaceHandle |
Description: Creates a virtual address space for binding device address spaces and returns a handle.
dev_as_start_addr is normally set to 0 and dev_as_end_addr is normally set to 0xFFFFFFFF.
svcAttachDeviceAddressSpace
Argument | Type | Name |
---|---|---|
(In) W0 | #DeviceName | DeviceId |
(In) X1 | Handle<DeviceAddressSpace> | DeviceAsHandle |
(Out) W0 | #Result | Ret |
Description: Attaches a device address space to a device.
svcDetachDeviceAddressSpace
Argument | Type | Name |
---|---|---|
(In) W0 | #DeviceName | DeviceId |
(In) X1 | Handle<DeviceAddressSpace> | DeviceAsHandle |
(Out) W0 | #Result | Ret |
Description: Detaches a device address space from a device.
svcMapDeviceAddressSpaceByForce
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<DeviceAddressSpace> | DeviceAsHandle |
(In) W1 | Handle<Process> | ProcessHandle |
(In) X2 | void* | SrcAddr |
(In) X3 | u64 | DeviceAsSize |
(In) X4 | u64 | DeviceAsAddr |
(In) W5 | #Permission | Permissions |
(Out) W0 | #Result | Ret |
Description: Maps an attached device address space to an userspace address.
dev_map_addr is the userspace destination address, while dev_as_addr is the source address between dev_as_start_addr and dev_as_end_addr (passed to #svcCreateDeviceAddressSpace).
The userspace destination address must have the MapDeviceAllowed bit set. Bit IsDeviceMapped will be set after mapping.
svcMapDeviceAddressSpaceAligned
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<DeviceAddressSpace> | DeviceAsHandle |
(In) W1 | Handle<Process> | ProcessHandle |
(In) X2 | void* | SrcAddr |
(In) X3 | u64 | DeviceAsSize |
(In) X4 | u64 | DeviceAsAddr |
(In) W5 | #Permission | Permissions |
(Out) W0 | #Result | Ret |
Description: Maps an attached device address space to an userspace address.
Same as #svcMapDeviceAddressSpaceByForce, but the userspace destination address must have the MapDeviceAlignedAllowed bit set instead.
svcUnmapDeviceAddressSpace
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<DeviceAddressSpace> | DeviceAsHandle |
(In) W1 | Handle<Process> | ProcessHandle |
(In) X2 | void* | SrcAddr |
(In) X3 | u64 | DeviceAsSize |
(In) X4 | u64 | DeviceAsAddr |
(Out) W0 | #Result | Ret |
Description: Unmaps an attached device address space from an userspace address.
svcSetProcessMemoryPermission
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<Process> | ProcessHandle |
(In) X1 | u64 | Addr |
(In) X2 | u64 | Size |
(In) W3 | void* | Perm |
(Out) W0 | #Result | Ret |
This sets the memory permissions for the specified memory with the supplied process handle.
This throws an error(0xD801) when the input perm is >0x5, hence -WX and RWX are not allowed.
svcMapProcessMemory
Argument | Type | Name |
---|---|---|
(In) X0 | u64 | SrcAddr |
(In) W1 | Handle<Process> | ProcessHandle |
(In) X2 | void* | DstAddr |
(In) X3 | u64 | Size |
(Out) W0 | #Result | Ret |
Maps the src address from the supplied process handle into the current process.
This allows mapping code and rodata with RW- permission.
svcUnmapProcessMemory
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<Process> | ProcessHandle |
(In) X1 | void* | DstAddr |
(In) X2 | u64 | SrcAddr |
(In) X3 | u64 | Size |
(Out) W0 | #Result | Ret |
Unmaps what was mapped by #svcMapProcessMemory.
svcQueryProcessMemory
Argument | Type | Name |
---|---|---|
(In) X0 | #MemoryInfo* | MemInfoPtr |
(In) W2 | Handle<Process> | ProcessHandle |
(In) X3 | u64 | Addr |
(Out) W0 | #Result | Ret |
(Out) W1 | PageInfo | PageInfo |
Equivalent to #svcQueryMemory except takes a process handle.
svcMapProcessCodeMemory
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<Process> | ProcessHandle |
(In) X1 | u64 | DstAddr |
(In) X2 | u64 | SrcAddr |
(In) X3 | u64 | Size |
(Out) W0 | #Result | Ret |
Takes a process handle, and maps normal heap in that process as executable code in that process. Used when loading NROs. This does not support using the current-process handle alias.
svcUnmapProcessCodeMemory
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<Process> | ProcessHandle |
(In) X1 | u64 | DstAddr |
(In) X2 | u64 | SrcAddr |
(In) X3 | u64 | Size |
(Out) W0 | #Result | Ret |
Unmaps what was mapped by #svcMapProcessCodeMemory.
svcCreateProcess
Argument | Type | Name |
---|---|---|
(In) X1 | #CreateProcessInfo* | InfoPtr |
(In) X2 | u64 | CapabilitiesPtr |
(In) X3 | u64 | CapabilitiesNum |
(Out) W0 | #Result | Ret |
(Out) W1 | Handle<Process> | ProcessHandle |
Takes a #CreateProcessInfo as input.
svcGetProcessInfo
Argument | Type | Name |
---|---|---|
(In) W0 | Handle<Process> | ProcessHandle |
(Out) W0 | #Result | Ret |
(Out) W1 | #ProcessState | State |
Returns an enum with value 0-7.
Debugging
[2.0.0+] Exactly 6 debug SVCs require that IsDebugMode is non-zero. Error 0x4201 is returned otherwise.
- svcBreakDebugProcess
- svcContinueDebugEvent
- svcWriteDebugProcessMemory
- svcSetDebugThreadContext
- svcTerminateDebugProcess
- svcSetHardwareBreakPoint
svcDebugActiveProcess stops execution of the target process, the normal method for resuming it requires svcContinueDebugEvent(see above). Closing the debug handle also results in execution being resumed.
Enum/Structures
ThreadContextRequestFlags
Bitfield of one of more of these:
Bit | Bitmask | Name |
---|---|---|
0 | 1 | NormalContext |
1 | 2 | |
2 | 4 | |
3 | 8 |
DeviceName
Value | Name |
---|---|
0 | DeviceName_AFI |
1 | DeviceName_AVPC |
2 | DeviceName_DC |
3 | DeviceName_DCB |
4 | DeviceName_HC |
5 | DeviceName_HDA |
6 | DeviceName_ISP2 |
7 | DeviceName_MSENCNVENC |
8 | DeviceName_NV |
9 | DeviceName_NV2 |
10 | DeviceName_PPCS |
11 | DeviceName_SATA |
12 | DeviceName_VI |
13 | DeviceName_VIC |
14 | DeviceName_XUSB_HOST |
15 | DeviceName_XUSB_DEV |
16 | DeviceName_TSEC |
17 | DeviceName_PPCS1 |
18 | DeviceName_DC1 |
19 | DeviceName_SDMMC1A |
20 | DeviceName_SDMMC2A |
21 | DeviceName_SDMMC3A |
22 | DeviceName_SDMMC4A |
23 | DeviceName_ISP2B |
24 | DeviceName_GPU |
25 | DeviceName_GPUB |
26 | DeviceName_PPCS2 |
27 | DeviceName_NVDEC |
28 | DeviceName_APE |
29 | DeviceName_SE |
30 | DeviceName_NVJPG |
31 | DeviceName_HC1 |
32 | DeviceName_SE1 |
33 | DeviceName_AXIAP |
34 | DeviceName_ETR |
35 | DeviceName_TSECB |
36 | DeviceName_TSEC1 |
37 | DeviceName_TSECB1 |
38 | DeviceName_NVDEC1 |
MapJitOperation
Value | Name |
---|---|
0 | MapJitOperation_MapOwner |
1 | MapJitOperation_MapSlave |
2 | MapJitOperation_UnmapOwner |
3 | MapJitOperation_UnmapSlave |
LimitableResource
Value | Name |
---|---|
0 | LimitableResource_Memory |
1 | LimitableResource_Threads |
2 | LimitableResource_Events |
3 | LimitableResource_TransferMemories |
4 | LimitableResource_Sessions |
ProcessEvent
Value | Name |
---|---|
0 | ProcessEvent_Created |
1 | ProcessEvent_DebugAttached |
2 | ProcessEvent_DebugDetached |
3 | ProcessEvent_Crashed |
4 | ProcessEvent_Running |
5 | ProcessEvent_Exiting |
6 | ProcessEvent_Exited |
7 | ProcessEvent_DebugSuspended |
DebugThreadParam
Value | Name |
---|---|
0 | DebugThreadParam_ActualPriority |
1 | |
2 | DebugThreadParam_CpuCore |
3 | |
4 | DebugThreadParam_CoreMask |
CreateProcessInfo
Offset | Length | Bits | Description |
---|---|---|---|
0 | 12 | ProcessName (doesn't have to be null-terminated) | |
0 | 4 | ProcessCategory (0: regular title, 1: kernel built-in) | |
0x10 | 8 | TitleId | |
0x18 | 8 | CodeAddr | |
0x20 | 4 | CodeNumPages | |
0x24 | 4 | MmuFlags | |
Bit0 | IsAarch64 | ||
Bit3-1 | #AddressSpaceType | ||
Bit4 | |||
Bit5 | EnableAslr | ||
Bit6 | IsSystem | ||
0x28 | 4 | ResourceLimitHandle | |
0x2C | 4 |
AddressSpaceType
Type | Name | Width | Description |
---|---|---|---|
0 | Normal_32Bit | 32 | |
1 | Normal_36Bit | 36 | |
2 | WithoutMap_32Bit | 32 | Appears to be missing map region [?] |
3 | [2.0.0+] Normal_39Bit | 39 |
MemoryInfo
Offset | Length | Description |
---|---|---|
0 | 8 | BaseAddress |
8 | 8 | Size |
0x10 | 4 | MemoryType: lower 8 bits of #MemoryState |
0x14 | 4 | #MemoryAttribute |
0x18 | 4 | Permission (bit0: R, bit1: W, bit2: X) |
0x1C | 4 | IpcRefCount |
0x20 | 4 | DeviceRefCount |
0x24 | 4 | Padding: always zero |
MemoryAttribute
Bits | Description |
---|---|
0 | IsBorrowed |
1 | IsIpcMapped: when IpcRefCount > 0. |
2 | IsDeviceMapped: when DeviceRefCount > 0. |
3 | IsUncached |
MemoryState
Bits | Description |
---|---|
7-0 | Type |
8 | PermissionChangeAllowed |
9 | ForceReadWritableByDebugSyscalls |
10 | IpcSendAllowed_Type0 |
11 | IpcSendAllowed_Type3 |
12 | IpcSendAllowed_Type1 |
14 | ProcessPermissionChangeAllowed |
15 | MapAllowed |
16 | UnmapProcessCodeMemoryAllowed |
17 | TransferMemoryAllowed |
18 | QueryPhysicalAddressAllowed |
19 | MapDeviceAllowed (#svcMapDeviceAddressSpace and #svcMapDeviceAddressSpaceByForce) |
20 | MapDeviceAlignedAllowed |
21 | IpcBufferAllowed |
22 | IsPoolAllocated/IsReferenceCounted |
23 | MapProcessAllowed |
24 | AttributeChangeAllowed |
25 | [4.0.0+] JitMemoryAllowed |
Value | Type | Meaning |
---|---|---|
0x00000000 | MemoryType_Unmapped | |
0x00002001 | MemoryType_Io | Mapped by kernel capability parsing in #svcCreateProcess. |
0x00042002 | MemoryType_Normal | Mapped by kernel capability parsing in #svcCreateProcess. |
0x00DC7E03 | MemoryType_CodeStatic | Mapped during #svcCreateProcess. |
[1.0.0+]
0x01FEBD04 [4.0.0+] 0x03FEBD04 |
MemoryType_CodeMutable | Transition from 0xDC7E03 performed by #svcSetProcessMemoryPermission. |
[1.0.0+]
0x017EBD05 [4.0.0+] 0x037EBD05 |
MemoryType_Heap | Mapped using #svcSetHeapSize. |
0x00402006 | MemoryType_SharedMemory | Mapped using #svcMapSharedMemory. |
0x00482907 | [1.0.0] MemoryType_WeirdMappedMemory | Mapped using #svcMapMemory. |
0x00DD7E08 | MemoryType_ModuleCodeStatic | Mapped using #svcMapProcessCodeMemory. |
[1.0.0+]
0x01FFBD09 [4.0.0+] 0x03FFBD09 |
MemoryType_ModuleCodeMutable | Transition from 0xDD7E08 performed by #svcSetProcessMemoryPermission. |
0x005C3C0A | MemoryType_IpcBuffer0 | IPC buffers with descriptor flags=0. |
0x005C3C0B | MemoryType_MappedMemory | Mapped using #svcMapMemory. |
0x0040200C | MemoryType_ThreadLocal | Mapped during #svcCreateThread. |
0x015C3C0D | MemoryType_TransferMemoryIsolated | Mapped using #svcMapTransferMemory when the owning process has perm=0. |
0x005C380E | MemoryType_TransferMemory | Mapped using #svcMapTransferMemory when the owning process has perm!=0. |
0x0040380F | MemoryType_ProcessMemory | Mapped using #svcMapProcessMemory. |
0x00000010 | MemoryType_Reserved | |
0x005C3811 | MemoryType_IpcBuffer1 | IPC buffers with descriptor flags=1. |
0x004C2812 | MemoryType_IpcBuffer3 | IPC buffers with descriptor flags=3. |
0x00002013 | MemoryType_KernelStack | Mapped in kernel during #svcCreateThread. |
0x00402214 | [4.0.0+] MemoryType_JitReadOnly | Mapped in kernel during #svcMapJitMemory. |
0x00402015 | [4.0.0+] MemoryType_JitWritable | Mapped in kernel during #svcMapJitMemory. |
ContinueDebugFlags
Bit | Bitmask | Description |
---|---|---|
0 | 1 | CancelSynchronization (only if ResumeAllThreads is set; cancels with error 0x6C01) |
1 | 2 | SwallowException |
2 | 4 | ResumeAllThreads |
DebugEventInfo
Offset | Length | Description |
---|---|---|
0 | u32 | EventType |
4 | u32 | Flags (bit0: NeedsContinue) |
8 | u64 | ThreadId |
0x10 | PerTypeSpecifics |
AttachProcess specific:
Offset | Length | Description |
---|---|---|
0x10 | u64 | TitleId |
0x18 | u64 | ProcessId |
0x20 | char[12] | ProcessName |
0x2C | u32 | MmuFlags |
AttachThread specific:
Offset | Length | Description |
---|---|---|
0x10 | u64 | ThreadId |
0x18 | u64 | TlsPtr |
0x20 | u64 | Entrypoint |
Exit specific:
Offset | Length | Description |
---|---|---|
0x10 | u64 | Type (0=PausedThread, 1=RunningThread, 2=TerminatedProcess) |
Exception specific:
Offset | Length | Description |
---|---|---|
0x10 | u64 | ExceptionType |
0x18 | u64 | FaultRegister |
0x20 | PerExceptionSpecifics |
DebugEventType
Value | Name |
---|---|
0 | DebugEvent_AttachProcess |
1 | DebugEvent_AttachThread |
2 | |
3 | DebugEvent_Exit |
4 | DebugEvent_Exception |
DebugExceptionType
Value | Name |
---|---|
0 | Exception_UndefinedInstruction |
1 | Exception_InstructionAbort |
2 | Exception_DataAbortMisc |
3 | Exception_PcSpAlignmentFault |
4 | Exception_DebuggerAttached |
5 | Exception_BreakPoint |
6 | Exception_UserBreak |
7 | Exception_DebuggerBreak |
8 | Exception_BadSvcId |
UndefinedInstruction specifics:
Offset | Length | Description |
---|---|---|
0x20 | u32 | Opcode |
BreakPoint specifics:
Offset | Length | Description |
---|---|---|
0x20 | u32 | IsWatchpoint |
UserBreak specifics:
Offset | Length | Description |
---|---|---|
0x20 | u32 | Info0 |
0x28 | u64 | Info1 |
0x30 | u64 | Info2 |
BadSvcId specifics:
Offset | Length | Description |
---|---|---|
0x20 | u32 | SvcId |
Exception handling
There is userland code for handling exceptions, however this doesn't seem to be executed on retail mode.
When a usermode exception occurs, it jumps to the main code binary entrypoint (main_binary_address + 0 == _start).
During normal boot _start is invoked with X0=0 and X1=main_thread_handle (triggering normal crt0 setup). During an usermode exception _start is invoked with X0=exception_info0_ptr and X1=exception_info1_ptr instead.
The _start method determines whether to boot normally or handle an exception if X0 is set to 0 or not.