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SVC

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[edit] System calls

Id NATIVE_FIRM ARM11 kernel notes Enabled for the TWL_FIRM ARM11 kernel Description
0x01 No Result ControlMemory(u32* outaddr, u32 addr0, u32 addr1, u32 size, u32 operation, u32 permissions) (outaddr is usually the same as the input addr0)
0x02 No Result QueryMemory(MemoryInfo* info, PageInfo* out, u32 Addr)
0x03 No void ExitProcess(void)
0x04 No Result GetProcessAffinityMask(u8* affinitymask, Handle process, s32 processorcount)
0x05 No Result SetProcessAffinityMask(Handle process, u8* affinitymask, s32 processorcount)
0x06 No Result GetProcessIdealProcessor(s32 *idealprocessor, Handle process)
0x07 No Result SetProcessIdealProcessor(Handle process, s32 idealprocessor)
0x08 Yes Result CreateThread(Handle* thread, func entrypoint, u32 arg, u32 stacktop, s32 threadpriority, s32 processorid)
0x09 Yes void ExitThread(void)
0x0A Yes void SleepThread(s64 nanoseconds)
0x0B Yes Result GetThreadPriority(s32* priority, Handle thread)
0x0C Yes Result SetThreadPriority(Handle thread, s32 priority)
0x0D No Result GetThreadAffinityMask(u8* affinitymask, Handle thread, s32 processorcount)
0x0E Stubbed beginning with 8.0.0-18. No Result SetThreadAffinityMask(Handle thread, u8* affinitymask, s32 processorcount)
0x0F No Result GetThreadIdealProcessor(s32* processorid, Handle thread)
0x10 Stubbed beginning with 8.0.0-18. No Result SetThreadIdealProcessor(Handle thread, s32 processorid)
0x11 No s32 GetCurrentProcessorNumber(void)
0x12 No Result Run(Handle process, StartupInfo* info) (This starts the main() thread. Buf+0 is main-thread priority, Buf+4 is main-thread stack-size.)
0x13 Yes Result CreateMutex(Handle* mutex, bool initialLocked)
0x14 Yes Result ReleaseMutex(Handle mutex)
0x15 Yes Result CreateSemaphore(Handle* semaphore, s32 initialCount, s32 maxCount)
0x16 Yes Result ReleaseSemaphore(s32* count, Handle semaphore, s32 releaseCount)
0x17 Yes Result CreateEvent(Handle* event, ResetType resettype)
0x18 Yes Result SignalEvent(Handle event)
0x19 Yes Result ClearEvent(Handle event)
0x1A Yes Result CreateTimer(Handle* timer, ResetType resettype)
0x1B Yes Result SetTimer(Handle timer, s64 initial, s64 interval)
0x1C Yes Result CancelTimer(Handle timer)
0x1D Yes Result ClearTimer(Handle timer)
0x1E No Result CreateMemoryBlock(Handle* memblock, u32 addr, u32 size, u32 mypermission, u32 otherpermission)
0x1F No Result MapMemoryBlock(Handle memblock, u32 addr, u32 mypermissions, u32 otherpermission)
0x20 No Result UnmapMemoryBlock(Handle memblock, u32 addr)
0x21 Yes Result CreateAddressArbiter(Handle* arbiter)
0x22 Yes Result ArbitrateAddress(Handle arbiter, u32 addr, ArbitrationType type, s32 value, s64 nanoseconds)
0x23 Yes Result CloseHandle(Handle handle)
0x24 Yes Result WaitSynchronization1(Handle handle, s64 nanoseconds)
0x25 Yes Result WaitSynchronizationN(s32* out, Handle* handles, s32 handlecount, bool waitAll, s64 nanoseconds)
0x26 No Result SignalAndWait(s32* out, Handle signal, Handle* handles, s32 handleCount, bool waitAll, s64 nanoseconds)
0x27 Yes Result DuplicateHandle(Handle* out, Handle original)
0x28 Yes s64 GetSystemTick(void) (This returns the total CPU ticks elapsed since the CPU was powered-on)
0x29 No Result GetHandleInfo(s64* out, Handle handle, HandleInfoType type)
0x2A Yes Result GetSystemInfo(s64* out, SystemInfoType type, s32 param)
0x2B Yes Result GetProcessInfo(s64* out, Handle process, ProcessInfoType type)
0x2C Yes Result GetThreadInfo(s64* out, Handle thread, ThreadInfoType type)
0x2D No Result ConnectToPort(Handle* out, const char* portName)
0x2E Stubbed No Result SendSyncRequest1(Handle session)
0x2F Stubbed No Result SendSyncRequest2(Handle session)
0x30 Stubbed No Result SendSyncRequest3(Handle session)
0x31 Stubbed No Result SendSyncRequest4(Handle session)
0x32 No Result SendSyncRequest(Handle session)
0x33 No Result OpenProcess(Handle* process, u32 processId)
0x34 No Result OpenThread(Handle* thread, Handle process, u32 threadId)
0x35 Yes Result GetProcessId(u32* processId, Handle process)
0x36 No Result GetProcessIdOfThread(u32* processId, Handle thread)
0x37 Yes Result GetThreadId(u32* threadId, Handle thread)
0x38 No Result GetResourceLimit(Handle* resourceLimit, Handle process)
0x39 No Result GetResourceLimitLimitValues(s64* values, Handle resourceLimit, LimitableResource* names, s32 nameCount)
0x3A No Result GetResourceLimitCurrentValues(s64* values, Handle resourceLimit, LimitableResource* names, s32 nameCount)
0x3B No Result GetThreadContext(ThreadContext* context, Handle thread) (Stubbed)
0x3C Yes Break(BreakReason)
0x3D Yes OutputDebugString(void const, int) (Does nothing on non-debug units)
0x3E No ControlPerformanceCounter(unsigned long long, int, unsigned int, unsigned long long)
0x47 No Result CreatePort(Handle* portServer, Handle* portClient, const char* name, s32 maxSessions)
0x48 No Result CreateSessionToPort(Handle* session, Handle port)
0x49 No Result CreateSession(Handle* sessionServer, Handle* sessionClient)
0x4A No Result AcceptSession(Handle* session, Handle port)
0x4B No Result ReplyAndReceive1(s32* index, Handle* handles, s32 handleCount, Handle replyTarget) (Stubbed)
0x4C No Result ReplyAndReceive2(s32* index, Handle* handles, s32 handleCount, Handle replyTarget) (Stubbed)
0x4D No Result ReplyAndReceive3(s32* index, Handle* handles, s32 handleCount, Handle replyTarget) (Stubbed)
0x4E No Result ReplyAndReceive4(s32* index, Handle* handles, s32 handleCount, Handle replyTarget) (Stubbed)
0x4F No Result ReplyAndReceive(s32* index, Handle* handles, s32 handleCount, Handle replyTarget)
0x50 Yes Result BindInterrupt(Interrupt name, Handle syncObject, s32 priority, bool isManualClear)
0x51 Yes Result UnbindInterrupt(Interrupt name, Handle syncObject)
0x52 Yes Result InvalidateProcessDataCache(Handle process, void* addr, u32 size)
0x53 Yes Result StoreProcessDataCache(Handle process, void const* addr, u32 size)
0x54 Yes Result FlushProcessDataCache(Handle process, void const* addr, u32 size)
0x55 Yes Result StartInterProcessDma(Handle* dma, Handle dstProcess, void* dst, Handle srcProcess, const void* src, u32 size, const DmaConfig& config )
0x56 Yes Result StopDma(Handle dma)
0x57 Yes Result GetDmaState(DmaState* state, Handle dma)
0x58 Yes RestartDma(nn::Handle, void *, void const*, unsigned int, signed char)
0x60 No Result DebugActiveProcess(Handle* debug, u32 processID)
0x61 No Result BreakDebugProcess(Handle debug)
0x62 No Result TerminateDebugProcess(Handle debug)
0x63 No Result GetProcessDebugEvent(DebugEventInfo* info, Handle debug)
0x64 No Result ContinueDebugEvent(Handle debug, u32 flags)
0x65 No Result GetProcessList(s32* processCount, u32* processIds, s32 processIdMaxCount)
0x66 No Result GetThreadList(s32* threadCount, u32* threadIds, s32 threadIdMaxCount, Handle domain)
0x67 No Result GetDebugThreadContext(ThreadContext* context, Handle debug, u32 threadId, u32 controlFlags)
0x68 No Result SetDebugThreadContext(Handle debug, u32 threadId, ThreadContext* context, u32 controlFlags)
0x69 No Result QueryDebugProcessMemory(MemoryInfo* blockInfo, PageInfo* pageInfo, Handle process, u32 addr)
0x6A No Result ReadProcessMemory(void* buffer, Handle debug, u32 addr, u32 size)
0x6B No Result WriteProcessMemory(Handle debug, void const* buffer, u32 addr, u32 size)
0x6C No Result SetHardwareBreakPoint(s32 registerId, u32 control, u32 value)
0x6D No GetDebugThreadParam(long long *, int *, nn::Handle, unsigned int, nn::dmnt::DebugThreadParam) (Disabled on regular kernel)
0x70 No ControlProcessMemory(Handle KProcess, unsigned int Addr0, unsigned int Addr1, unsigned int Size, unsigned int Type, unsigned int Permissions)
0x71 No MapProcessMemory(Handle KProcess, unsigned int StartAddr, unsigned int EndAddr)
0x72 No UnmapProcessMemory(Handle KProcess, unsigned int StartAddr, unsigned int EndAddr)
0x73 No CreateProcess(Handle* HandleInfo_out, struct CreateProcessInfo, u32 code_ptr, u32 ro_ptr, u32 data_ptr)
0x74 Stubbed No
0x75 No SetupProcess(Handle* KProcess_out, Handle HandleInfo_in, u32 arm11kernelcaps_ptr, u32 arm11kernelcaps_num)
0x76 No TerminateProcess(Handle)
0x77 No (Handle KProcess, Handle KResourceLimit)
0x78 No CreateResourceLimit(Handle *KResourceLimit)
0x79 No  ?
0x7A Stubbed beginning with 2.0.0-2 Yes AddCodeSegment? (unsigned int Addr, unsigned int Size)
0x7B Available(normally not accessible due to SVC-access-control). No Backdoor(unsigned int CodeAddress) This is used/accessible by Process9.
0x7C Yes KernelSetState(unsigned int Type, unsigned int Param0, unsigned int Param1, unsigned int Param2) (The Type determines the usage of each param)
0x7D No QueryProcessMemory(MemInfo *Info, unsigned int *Out, Handle KProcess, unsigned int Addr)
0xFF Yes Debug related (The Syscall access control mask doesn't apply for this SVC)

Note that "stubbed" here means that the SVC only returns an error.

[edit] CreateThread

R0=s32 threadpriority
R1=func entrypoint
R2=u32 arg
R3=u32 stacktop
R4=s32 processorid
Result result=R0
Handle* thread=R1

This processorid is a bitmask for which processors the thread can be run on. Bit value zero enables thread execution for this CPUID, bit value one disables thread execution for this CPUID. Bit0-bit1 are for CPUID0-CPUID1. The s32 processorid must be <=2. The thread priority value must be in the following range: 0x0..0x3F.

The stacktop must be aligned to 0x8-bytes, otherwise when not aligned to 0x8-bytes the ARM11 kernel clears the low 3-bits of the stacktop address.

[edit] Types and structures

[edit] enum MemoryState

Memory state flags Bit
FREE 0
RESERVED 1
IO 2
STATIC 3
CODE 4
PRIVATE 5
SHARED 6
CONTINUOUS 7
ALIASED 8
ALIAS 9
ALIAS CODE 10
LOCKED 11

[edit] enum PageFlags

Page flags Bit
LOCKED 0
CHANGED 1

[edit] enum MemoryOperation

Memory operation Id
FREE 1
RESERVE 2
COMMIT 3
MAP 4
UNMAP 5
PROTECT 6
REGION APP 0x100
REGION SYSTEM 0x200
REGION BASE 0x300
LINEAR 0x10000

The LINEAR memory-operation indicates that the mapped physical address is always MappedVAddr+0x0C000000, thus this memory can be used for hardware devices' DMA(such as the GPU). Addr0+size for this must be within the 0x14000000-0x1C000000 range when Addr0 is non-zero(Addr1 must be zero), Addr0 isn't actually used by svcControlMemory for mapping memory: Addr0 is not used by the kernel after doing address-range checks. The kernel determines what physical-address to use by allocating memory from FCRAM(about the same way as other memory), which is then used to determine the virtual-address.

8.0.0-18 added a new memory mapping(0x30000000-0x38000000) for LINEAR memory, this replaces the original mapping for newer titles. The kernel uses the new mapping when the process memory-region is BASE, or when the process kernel-release-version field is >=0x022c(2.44 / system-version 8.0.0-18).

The input mem-region value for svcControlMemory is only used(when non-zero) when the PID is value 1, for the FIRM ARM11 "loader" module.

[edit] enum MemoryPermission

Memory permission Id
NONE 0
READ 1
WRITE 2
READWRITE 3
DONTCARE 0x10000000


[edit] enum ResetType

Reset type Id
ONESHOT 0
STICKY 1
PULSE 2

[edit] struct MemoryInfo

Type Field
u32 Base address
u32 Size
u32 Permission
enum MemoryState State

[edit] struct PageInfo

Type Field
u32 Flags

[edit] struct StartupInfo

Type Field
s32 Priority
u32 Stack size
s32 argc
s16* argv
s16* envp


[edit] Processes

Each process can only use SVCs which are enabled in the exheader for this process. The ARM11 kernel SVC handler checks whether the SVC is enabled in the syscall access control mask stored on the SVC-mode stack, when the SVC isn't enabled a kernelpanic() is triggered. Each process has a separate SVC-mode stack, this stack and the syscall access mask stored here is initialized when the process is started. Applications normally only have access to SVCs <=0x3D, however not all SVCs <=0x3D are accessible to the application. The majority of the SVCs accessible to applications are unused by the application.

Each process has a separate handle-table, the size of this table is stored in the exheader. The handles in a handle-table can't be used in the context of other processes, since those handles don't exist in other handle-tables.

0xFFFF8001 is a handle alias for the current KProcess, and 0xFFFF8000 is a handle alias for the current KThread.

Calling svcBreak on retail will only terminate the process which called this SVC.

[edit] Threads

For svcCreateThread the input address used for Entrypoint_Param and StackTop are normally the same, however these can be arbitrary. For the main thread the Entrypoint_Param is value 0.

Using CloseHandle() with a KThread handle will terminate the specified thread.

[edit] Memory Mapping

ControlMemory and MapMemoryBlock can be used to map memory pages, these two SVCs only support mapping execute-never R/W pages. The input permissions parameter for these SVCs must be <=3, where value zero is used when un-mapping memory. Bitmask 0xf00 for ControlMemory parameter MemoryType is the memory-type, when this is zero the memory-type is loaded from the kernel flags stored in the exheader ARM11 kernel descriptors, for the process using the SVC. ControlMemory parameter MemoryType with value 0x10003 is used for mapping the GSP heap. The low 8-bits are the type: 1 is for un-mapping memory, 3 for mapping memory. Type4 is used to mirror the RW memory at Addr1, to Addr0. Type4 will return an error if Addr1 is located in read-only memory. Addr1 is not used for type1 and type3.

The ARM11 kernel does not allow processes to create shared memory blocks via svcCreateMemoryBlock, when the process memorytype(from the kernel flags stored in the exheader kernel descriptor) is the application memorytype, and when addr=0. It's unknown how the kernel handles addr=0 when the memorytype is not the application memorytype. When addr is non-zero, it must be located in memory which is already mapped.

ControlProcessMemory maps memory in the specified process, this is the only SVC which allows mapping executable memory. Format of the permissions field for memory mapping SVCs: bit0=R, bit1=W, bit2=X. Type6 sets the Addr0 memory permissions to the input permissions, for already mapped memory. Type is the MemoryOperation enum, without the memory-type/memory-region. ControlProcessMemory only supports type4, type5, and type6. ControlProcessMemory does not support using the current KProcess handle alias.

MapProcessMemory maps RW memory starting at address 0x00100000 in the specified KProcess, at the specified StartAddr in the current process. MapProcessMemory then maps 0x08000000 in the specified process, to StartAddr+0x7f00000 in the current process. UnmapProcessMemory unmaps the memory which was mapped by MapProcessMemory.

Note that with the MAP MemoryOperation, the kernel will refuse to MAP memory for the specified addr1, when addr1 was already used with another MAP operation as addr1. The kernel also doesn't allow memory to be freed via the FREE MemoryOperation, when other virtual-memory is mapped to this same memory(when the MAP MemoryOperation was used with this memory with addr1).

[edit] DMA

The CTRSDK code for using svcStartInterProcessDma will execute svcBreak when svcStartInterProcessDma returns an error(except for certain error value(s)). Therefore on retail, triggering a svcStartInterProcessDma via a system-module which results in an error from svcStartInterProcessDma will result in the system-module terminating.

[edit] Debugging

DebugActiveProcess is used to attach to a process for debugging. This SVC can only be used when the target process' ARM11 descriptors stored in the exheader have the kernel flag for "Enable debug" set. Otherwise when that flag is clear, the kernel flags for the process using this SVC must have the "Force debug" flag set.

[edit] KernelSetState

Type Enabled for the NATIVE_FIRM ARM11 kernel Enabled for the TWL_FIRM ARM11 kernel Description
0 Yes No This initializes the programID for launching FIRM, then triggers launching FIRM. Param0 and Param2 are unused. Param1 is the programID-low, and the programID-high is 0x00040138.
1 Yes Yes Unknown, does nothing with the TWL_FIRM ARM11 kernel.
2 Yes Yes  ?
3 Yes No This used for initializing the 0x1000-byte buffer used by the launched FIRM. Param2 is unused. When Param0 is value 1, this buffer is copied to the beginning of FCRAM at 0xF0000000, and Param1 is unused. When Param0 is value 0, this kernel buffer is mapped to process address Param1.
4 No Yes Param0-Param3 are unused. This unmaps(?) the following virtual memory by writing value physaddr(where physaddr base is 0x80000000) to the L1 MMU table entries: 0x00300000..0x04300000, 0x08000000..0x0FE00000, and 0x10000000..0xF8000000.
5 Yes Yes  ?
6 Yes No Debug related?
7 Yes No This triggers ARM11 kernel I2C code, Param0-Param3 are unused. This ARM11 kernel I2C code will never return. Device address 0x4a via the second I2C bus is used here. This triggers a hardware system reboot via poking an I2C MCU register: register address 0x20 is written to with value 4.
8 Yes No Alternate unused FIRM launch code-path, with different PXI FIFO word constants.
9 Yes, implemented at some point after system-version v4.5.  ? Unknown

[edit] GetSystemInfo

SystemInfoType value s32 param Description
0 0 This writes the total used memory size in the following memory regions to out: APPLICATION, SYSTEM, and BASE.
0 1 This writes the total used memory size in the APPLICATION memory region to out.
0 2 This writes the total used memory size in the SYSTEM memory region to out.
0 3 This writes the total used memory size in the BASE memory region to out.
26 Unused This writes the total number of processes which were directly launched by the kernel, to out. For the NATIVE_FIRM/SAFE_MODE_FIRM ARM11 kernel, this is normally 5, for processes sm, fs, pm, loader, and pxi.

[edit] GetProcessInfo

ProcessInfoType value Available since system version Description
9-19 8.0.0-18 This only returns error 0xD8E007ED.
20 8.0.0-18 low u32 = (0x20000000 - <LINEAR virtual-memory base for this process>). That is, the output value is the value which can be added to LINEAR memory vaddrs for converting to physical-memory addrs.
21-23 8.0.0-18 This only returns error 0xE0E01BF4.

[edit] CreateProcess

struct CreateProcessInfo {
	// All addresses are given virtual for the process to be created.
	// All sizes/offsets are in given in 0x1000-pages.
	u8  codeset_name[8];
	u32 text_addr;
	u32 text_size;
	u32 ro_addr;
	u32 ro_size;
	u32 data_addr;
	u32 data_size;
	u32 ro_offset;
	u32 data_offset;
	u32 bss_size+data_size;
	u8  program_id[8];
	u32 hmm?[2];
}

[edit] SVC7B Backdoor

This saves SVC-mode SP+LR on the user-mode stack, then sets the SVC-mode SP to the user-mode SP. This then calls the specified code in SVC-mode. Once the called code returns, this pops the saved SP+LR off the stack for restoring the SVC-mode SP, then returns from the svc7b handler. Note that this svc7b handler does not disable IRQs, if any IRQs/context-switches occur while the SVC-mode SP is set to the user-mode one here, the ARM11-kernel will crash(which hangs the whole ARM11-side system).

[edit] Kernel error-codes

See Error codes.

Error-code value Description
0xC860180A Not enough free memory available for memory allocation.
0xC920181A The session was closed due to the other process terminating / calling svcBreak.
0xD8E007F1 This error indicates Misaligned address.
0xD8E007F7 This error indicates that the input handle used with the SVC does not exist in the process handle-table, or that the handle kernel object type does not match the type used by the SVC.
0xD9000402 Invalid memory permissions for input/output buffers, for svcStartInterProcessDma.
0xD92007EA This error is returned when a process attempts to use svcCreateMemoryBlock when the process memorytype is the application memorytype, and when addr=0.
0xF8C007F4 Invalid type/param0-param3 input for svcKernelSetState.
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