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→ARM11 User-land memory regions
All userland memory is mapped with RW permissions for privileged-mode. However, normally the ARM11 kernel only uses userland read/write instructions(or checks that the memory can be written from userland first) for accessing memory specified by [[SVC|SVCs]].
All userland memory is mapped with RW permissions for privileged-mode. However, normally the ARM11 kernel only uses userland read/write instructions(or checks that the memory can be written from userland first) for accessing memory specified by [[SVC|SVCs]].
The virtual memory located below 0x20000000 is process-unique, processes can't directly access memory for other processes. The virtual memory starting at 0x20000000 is only accessible in privileged-mode. When service [[Services API|commands]] are used, the kernel maps memory in the destination process for input/output buffers, where the addresses in the command received by the process is replaced by this mapped memory. When this is an input buffer, the buffer data is copied to the mapped memory. When this is an output buffer, the data stored in the mapped memory is copied to the destination buffer specified in the command.