Is the NVRAM on Intel Macs mapped in memory? If so, where is the address that it is located at? Apologies if this question is not strictly a ‘programming’ question.
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Is the NVRAM on Intel Macs mapped in memory? If so, where is the address that it is located at? Apologies if this question is not strictly a ‘programming’ question.
I don’t know, but the kernel doesn’t access NVRAM that way, so likely neither should you. Short of exhaustively searching memory or figuring out a way to debug/disassemble the EFI implementation, I don’t think this is particularly doable.
Access to NVRAM is provided by EFI Variable Services. (U)EFI doesn’t provide an interface to get at the nonvolatile storage for variables.
Going up a level, the kext that implements the NVRAM interface by setting/getting EFI variables is
/System/Library/Extensions/AppleEFIRuntime.kext/Contents/PlugIns/AppleEFINVRAM.kext. It is not open source.There are APIs available for manipulating NVRAM contents, and the
nvramtool itself is open source.