On 11.09.2023 19:41, Stephan Gerhold wrote: > At a first glance the MBA memory region on MSM8916 looks intentionally > placed at the fixed address 0x8ea00000. This is what the ELF headers of > the firmware specify as base address, and the typical Qualcomm-specific > bits suggest the binary is not relocatable. > > However, on a closer look this is pointless: Unlike other firmware > images the hardware expects to have the raw ELF image loaded to the MBA > region, including the ELF header (without parsing it at all). This > means that we actually just load the ELF header (not the code!) at > 0x8ea00000. The real LOAD segments follow at arbitrary aligned > addresses depending on the structure of the ELF binary. > > In practice it looks like we can use an arbitrary 1 MiB-aligned region > for MBA. The downstream/vendor kernel just allocates this dynamically > at an arbitrary (aligned) address. > > Drop the pointless fixed address and use the new dynamic reserved > memory mechanism to allocate a region close to the others. This reduces > gaps in the memory map and provides Linux with more contiguous memory. > > Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx> > --- Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> Konrad
