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2021-01-12csky: Add memory layout 2.5G(user):1.5G(kernel)Guo Ren1-2/+8
There are two ways for translating va to pa for csky: - Use TLB(Translate Lookup Buffer) and PTW (Page Table Walk) - Use SSEG0/1 (Simple Segment Mapping) We use tlb mapping 0-2G and 3G-4G virtual address area and SSEG0/1 are for 2G-2.5G and 2.5G-3G translation. We could disable SSEG0 to use 2G-2.5G as TLB user mapping. Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
2020-04-03csky: Fixup cpu speculative execution to IO areaGuo Ren1-0/+5
For the memory size ( > 512MB, < 1GB), the MSA setting is: - SSEG0: PHY_START , PHY_START + 512MB - SSEG1: PHY_START + 512MB, PHY_START + 1GB But the real memory is no more than 1GB, there is a gap between the end size of memory and border of 1GB. CPU could speculatively execute to that gap and if the gap of the bus couldn't respond to the CPU request, then the crash will happen. Now make the setting with: - SSEG0: PHY_START , PHY_START + 512MB (no change) - SSEG1: Disabled (We use highmem to use the memory of 512MB~1GB) We also deprecated zhole_szie[] settings, it's only used by arm style CPUs. All memory gap should use Reserved setting of dts in csky system. Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
2019-04-22csky: Support vmlinux bootup with MMU offGuo Ren1-53/+7
Modify SETUP_MMU macro to fit on both MMU-on or MMU-off enviornment and vmlinux could bootup from MMU off enviornment for some cases. Unify the style of _start and _start_smp_secondary in head.S to make head.S looks more concise and easy to understand. Signed-off-by: Guo Ren <ren_guo@c-sky.com> Cc: Arnd Bergmann <arnd@arndb.de>
2018-10-25csky: Kernel bootingGuo Ren1-0/+77
This patch add boot code. Thx boot params is all in dtb and it's the only way to let kernel get bootloader param information. Signed-off-by: Guo Ren <ren_guo@c-sky.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de>