IPC: Difference between revisions

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= Message Structure =

IPC ~~commands~~ are written to the [[Thread Local Storage]] at offset 0x80 and submitted using [[SVC|svcSendSyncRequest]]. If the kernel was able to dispatch the request, the server reply will be written to TLS+0x80. ~~Often~~ the second word of the response data is ~~the~~ error code (or 0 if success). IPC ~~commands~~ and IPC replies follow the same structure.

IPC requests are written to the [[Thread Local Storage]] at offset 0x80 and submitted using [[SVC|svcSendSyncRequest]]. If the kernel was able to dispatch the request, the server reply will be written to TLS+0x80 before svcSendSyncRequest returns. By convention, the second word of the response data is an error code (or 0 on success). IPC requests and IPC replies follow the same structure.

Every IPC message starts with a u32 header code. Parameters, if any, are written following this header. There are "normal parameters", which are fixed-size words, and there are "translate parameters", which are of flexible size and each of which begins with a header. The entire command has the following structure:

Every IPC message starts with a u32 header code. Parameters (if any) are written following this header. There are "normal parameters", which are fixed-size words, and there are "translate parameters", which are of flexible size and each of which begins with a header. The entire command has the following structure:

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 = Message Structure =
-IPC commands are written to the [[Thread Local Storage]] at offset 0x80 and submitted using [[SVC|svcSendSyncRequest]]. If the kernel was able to dispatch the request, the server reply will be written to TLS+0x80. Often the second word of the response data is the error code (or 0 if success). IPC commands and IPC replies follow the same structure.
+IPC requests are written to the [[Thread Local Storage]] at offset 0x80 and submitted using [[SVC|svcSendSyncRequest]]. If the kernel was able to dispatch the request, the server reply will be written to TLS+0x80 before svcSendSyncRequest returns. By convention, the second word of the response data is an error code (or 0 on success). IPC requests and IPC replies follow the same structure.
-Every IPC message starts with a u32 header code. Parameters, if any, are written following this header. There are "normal parameters", which are fixed-size words, and there are "translate parameters", which are of flexible size and each of which begins with a header. The entire command has the following structure:
+Every IPC message starts with a u32 header code. Parameters (if any) are written following this header. There are "normal parameters", which are fixed-size words, and there are "translate parameters", which are of flexible size and each of which begins with a header. The entire command has the following structure:
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