Difference between revisions of "IPC"
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| Number of normal parameters (=y) | | Number of normal parameters (=y) | ||
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| − | | 16- | + | | 16-31 |
| Command ID | | Command ID | ||
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| − | |||
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| 0x0000000C <nowiki>|</nowiki> (size<<4) | | 0x0000000C <nowiki>|</nowiki> (size<<4) | ||
| − | | The corresponding value contains a ptr to a buffer of said size. | + | | The corresponding value contains a ptr to a buffer of said size, for PXI(eventually sent to the ARM9) commands' input/output buffers. |
|} | |} | ||
Revision as of 22:31, 28 April 2014
Every RPC command sent to services starts with a u32 header code:
| Bits | Description |
|---|---|
| 0-5 | Number of translate parameters (=x) |
| 6-15 | Number of normal parameters (=y) |
| 16-31 | Command ID |
The entire command has the following structure:
| Word | Size | Description |
|---|---|---|
| 0 | 1 | Header code |
| 1 | x | Normal parameters |
| x | y | Translate parameters |
Translate parameters are modified/translated transparently by the kernel. They are used to transfer handles/buffers between the different processes.
The type of parameter is described by the bits 1-3 in the translation descriptor. Parameter types accepted for sending by the kernel are: 0, 1, 2, 5, 6, 7. Type 0 is used to send handles across processes:
if desc & 0x30 == 0x20:
write process id to value
else:
translate handle
if desc & 0x30 == 0x10:
close handle for caller
For replies, only 0, 1, 5, 6, 7 are allowed. In other words any type 2 fields must be zeroed before calling svcReplyAndReceive on the server-side. For replies type 0, 1, 2 are ignored. Types 5, 6, 7 do something with the mem pointer upon reply. The type 0 descriptor can be used to ignore parameters. The number of parameters covered by a type-0 descriptor is (desc >> 26) + 1.
| Descriptor | Description |
|---|---|
| 0x00000000 | The corresponding value is a KHandle, that should be closed in calling process. |
| 0x00000010 | The corresponding value is a KHandle, that will be shared/duplicated? |
| 0x00000020 | Let kernel set value to calling process ProcessID |
| 0x0000???2 | (size<<14) | The corresponding value contains a ptr to a buffer of said size. |
| 0x0000000A | (size<<4) | The corresponding value contains a ptr to a buffer of said size. |
| 0x0000000C | (size<<4) | The corresponding value contains a ptr to a buffer of said size, for PXI(eventually sent to the ARM9) commands' input/output buffers. |