Cafe OS Syscalls

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Syscalls

Cafe OS syscalls are issued by doing the following:

li r0, 0x0100 # load syscall value->r0
sc            # syscall instruction
blr           # return control to program

When you send a call to the kernel, it goes to 0xFFF00C00, which then jumps to 0xFFF021A0 + (fastcall << 5).

Normal syscalls are divisible by 0x100, so all of them will jump to 0xFFF0021A0 itself, which is a jump to the table dispatcher.

The dispatcher uses a RAMPID and the syscall dispatch tables at 0xFFEAAA40 (user table in 5.5.1) and 0xFFE84850 (loader table in 5.5.1) to get the secondary table each RAMPID is able to access.

RAMPIDs 0 (Kernel), 2, and 3 all use an empty table, while RAMPID 1 (root.rpx) has its own table with a few unique calls. RAMPIDs 4 (background app), 5 (home menu), and 6 (error display) share the same table and RAMPID 7 (foreground app) has it's own. See Cafe OS wiki page for more info.

Below is a list of what all of them, as well as the loader which has its own bare-bones table, have access to call. (sp) indicates that the loader uses a separate function for that syscall. Additionally, the loader uses the same function for IPCKDriver_Open/Close.

# Name root Sys App Ldr
0x0000 ConsoleWrite X X X X (sp)
0x0100 AppPanic X X X X
0x0200 EffectiveToPhysical X X X
0x0300 PhysicalToEffectiveCached X X X
0x0400 PhysicalToEffectiveUncached X X X
0x0500 ValidateAddrRange X X X X
0x0600 UpdateCoreTime X X X
0x0800 SetUserModeExHandler X X X
0x0B00 AllocateTimer X X X
0x0C00 FreeTimer X X X
0x0D00 PrimeTimer X X X
0x0E00 StopTimer X X X
0x0F00 DumpModuleList X X X
0x1000 SetInterruptHandler X X X
0x1100 GetInterruptHandler X X X
0x1200 DisableInterrupt X X X
0x1300 EnableInterrupt X X X
0x1400 ClearAndEnableInterrupt X X X
0x1500 GetInterruptStatus X X X
0x1600 ClearInterruptStatus X X X
0x1700 FindClosestSymbol X X X X (sp)
0x1900 Exit/Halt X X X
0x1A00 GetInfo X X X
0x1B00 SetInfo X X X
0x1C00 ReleaseCore X X X
0x1D00 SendICI X X X
0x1E00 IPCKDriver_{Loader|User}Open X X X X (sp)
0x1F00 IPCKDriver_{Loader|User}Close X X X X (sp)
0x2000 IPCKDriver_SubmitRequest X X X X (sp)
0x2200 GetEnvironmentVariable X X X
0x2700 GetNotifyTarget X X X
0x2800 ProcCtrl X X X
0x2900 GetForegroundBucket X X X
0x2A00 RequestSwitch X X X
0x2B00 LaunchTitleArgvStr X X X
0x2C00 ProcYield X X X
0x2E00 GetSystemMessage X X X
0x2F00 GetCallArgs X X X
0x3000 GetAbsoluteSystemTimeInternal X X X
0x3100 SetAbsoluteSystemTimeInternal X X X
0x3200 Driver_Register X X X
0x3300 Driver_Deregister X X X
0x3800 AllocVirtAddr X X X
0x3900 FreeVirtAddr X X X
0x3A00 GetMapVirtAddrRange X X X
0x3B00 GetDataPhysAddrRange X X X
0x3C00 GetAvailPhysAddrRange X X X
0x3D00 MapMemory X X X
0x3E00 UnmapMemory X X X
0x3F00 LogBuffer X X X X
0x4000 LogArgs X X X X
0x4100 LogFunc X X X X
0x4200 LogReportKernel X X X X
0x4300 LogRetrieve X X X X
0x4400 (unknown) X X X
0x4500 (unknown) X X X
0x4600 save_fpu X X X
0x4700 Driver_CopyFromSaveArea X X X
0x4800 Driver_CopyToSaveArea X X X
0x4900 SavesDone_ReadyToRelease X X X
0x4A00 SetAlarm X X X
0x4B00 SetDABR X X X
0x4C00 SetIABR X X X
0x4D00 GetProcessInfo X X X
0x4E00 GetCodegenVirtAddrRange X X X
0x4F00 LoaderCall X X X
0x5000 RPLLoaderResumeContext X
0x5200 WaitIopComplete X
0x5300 FlushCode X
0x5400 FlushData X
0x5500 UpdateHeartbeat X
0x5600 LogEntry X
0x5700 FastClearMemory X
0x5800 GetBusClockSpeed X
0x5900 GetSharedArea X X X
0x5A00 SendPolicy X X X
0x5B00 GetProcessIndex X
0x5C00 IPCKDriver_PollLoaderCompletion X
0x5D00 BlockLogSave X X X
0x5E00 FinishInitandPreload X
0x5F00 ContinueStartProcess X
0x6000 OpenMCP X
0x6100 QuerySwitchReady X X X
0x6200 launch_title X X X
0x6300 call_title X X X
0x6400 SetTimeInternal X
0x6500 do_nothing (blr) X X X
0x6600 ProfileEntry (blr) X
0x6700 RequestFastExit X X X
0x6800 CoreInitDone X X X
0x6900 GetSwitchTarget X X X
0x6A00 AcquireDone X X X
0x6B00 GetBuiltSDKVersion X X X
0x6C00 SystemFatal X X X
0x6E00 SwitchSecCodeGenMode X X X
0x6F00 IopShell_RegisterCallback X X X
0x7000 GetTitleVersion X X X
0x7100 IsTestKernel X X X
0x7200 ForceFullRelaunch X X X
0x7300 Recycle X
0x7400 get_mode_flags X X X X
0x7500 QueryVirtAddr X X X
0x7600 GetCodegenCore X X X
0x7700 GetSecCodeGenMode X X X
0x7800 CodegenCopy X X X
0x7900 LoadShared X
0x7A00 SetExceptionCallback X X X
0x7B00 IopShell_InjectCommand X X X
0x7C00 Kill X X X
0x7D00 EnableOverlayArena X X X
0x7E00 DisableOverlayArena X X X
0x7F00 GetSystemMode X X X
0x8000 SystemMode_RegisterCallback X X X
0x8100 ZeroProcessMemory X
0x8200 HandleIopPowerEvents X
0x8300 ConsoleTimestamp X X X X
0x8400 ValidateOverlayRange X
0x8500 BadSysCall (jump to null on purpose) X X X X

Fastcalls

Fastcalls, on the other hand, are system calls that aren't routed through the dispatcher and can be accessed by any RAMPID. Attempting to access an unimplemented fastcall will redirect the code flow to syscall 0x0100 (AppPanic).

Below is a list of all the currently supported fastcalls.

# Name
0x0000 (default branch to syscall dispatcher)
0x0001 SyncEIEIO
0x0006 LoadContext
0x0007 SaveContext
0x0008 SetCurrentContext
0x0009 GetCurrentFPUContext
0x000A SetCurrentFPUContext
0x000B CompareAndSwapCurrentFPUContext
0x000C WriteGatherInit
0x000D SetPerformanceMonitor
0x000E FlushDMAQueue
0x000F do_nothing (rfi)
0x0010 DisableFPU (???)
0x0011 ReadRegister32Ex
0x0012 WriteRegister32Ex
0x0013 Unknown (FPU?)
0x0014 Unknown (FPU?)
0x0015 Unknown (FPU?)
0x0016 Unknown (FPU?)
0x0017 WriteGatherGetPtr
0x0018 EnableFPU (???)
0x0019 GetSecurityLevel (always zero)
0x001A BadFastCall (jump to error on purpose)

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