Ben Avison
authored
Add a new reason code, OS_Memory 22, equivalent to OS_Memory 14, but accepting a 64-bit physical address in r1/r2. Current ARM architectures can only express 40-bit or 32-bit physical addresses in their page tables (depending on whether they feature the LPAE extension or not) so unlike OS_Memory 14, OS_Memory 22 can return an error if an invalid physical address has been supplied. OS_Memory 15 should still be used to release a temporary mapping, whether you claimed it using OS_Memory 14 or OS_Memory 22. The logical memory map has had to change to accommodate supersection mapping of the physical access window, which needs to be 16MB wide and aligned to a 16MB boundary. This results in there being 16MB less logical address space available for dynamic areas on all platforms (sorry) and there is now a 1MB hole spare in the system address range (above IO). The internal function RISCOS_AccessPhysicalAddress has been changed to accept a 64-bit physical address. This function has been a candidate for adding to the kernel entry points from the HAL for a long time - enough that it features in the original HAL documentation - but has not been so added (at least not yet) so there are no API compatibility issues there. Requires RiscOS/Sources/Programmer/HdrSrc!2