On 01/27/2014 06:52 PM, Russell King - ARM Linux wrote: > On Mon, Jan 27, 2014 at 06:45:50PM +0100, Michal Simek wrote: >> Why 0x4000? IRC Linux for ARM is using space for any purpose. >> Russell knows this much better than I. > > Probably because as the kernel is loaded at 0x8000, it will place the > swapper page table at 0x4000, thus covering from 0x4000 upwards. Ah yeah swapper. > > Thus, the majority of your un-DMA-able memory will be kernel text or > swapper page tables. Yes, exactly. 0x0 - 0x4000 - reserving not to be used by DMA 0x4000 - 0x8000 swapper page table 0x8000 - 0x80000 kernel text + up Thanks, Michal -- Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91 w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/ Maintainer of Linux kernel - Xilinx Zynq ARM architecture Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform
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