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Reference for this info : offset 0x448 ccapi.prx in ccapi 2.80 rev5 this is the function called to use ccsc(command id, ... );


This is how you can create CCAPI syscall functions.<br>
This is how you can create CCAPI syscall functions.<br>
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== How does the custom CPU instruction work? ==
This is a writeup by PHTNC, I can't say if this is the exact way on how it works, I assume this is how it works.<br>
Some people might be wondering, how did Enstone implement a custom CPU instruction that the CPU actually understands?<br>
While the PS3 OS is closed source and seems to look like to be a completely different OS than what we know today (Linux, BSD, macOS, Windows)<br>
CellOS (PS3 OS Name) is actually a fork of Free- and NetBSD. So it contains stuff that are also present in different Unix OS'.<br>
You have to imagine it like that, the OS and CPU communicate with each other and tell each other on what's valid and what's invalid running on the CPU.<br>
This also goes for instructions. That means, when for example the CPU reads an (for the CPU) invalid instruction in kernel or process space, it tells the OS that it has no clue what this is,<br>
it proceeds to "ask" the OS if the OS knows what the instruction means. In normal cases, the OS doesn't know either what the read instruction means.<br>
At this point, it depends on what OS you're on. In regular Unix systems like Linux or BSD, a system exception called SIGILL (SIGnal ILLegal instruction) is raised.<br>
The OS sends a SIGILL Signal to the affected process, this causes the process to terminate itself immediately, signals like that cannot be caught by the process.<br>
CCAPI probably hooks a function in the area, where the SIGILL signal is handled and checks if the invalid instruction is 0xEF455314.<br>
If the hooked function sees, that the CPU hit 0xEF455314, then it proceeds to read a value from register R3 and makes a switch on that value.<br>
Then it starts executing a CCAPI function and proceeds with the normal code execution once CCAPI finished executing its own functions.<br>
If the hooked function sees another invalid instruction other than 0xEF455314, it will send a SIGILL signal to the affected process.


Reference for this info : offset 0x448 ccapi.prx in ccapi 2.80 rev5 this is the function called to use ccsc(command id, ... );


{{Reverse engineering}}<noinclude>[[Category:Main]]</noinclude>
{{Reverse engineering}}<noinclude>[[Category:Main]]</noinclude>
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