On Thu, 01 Oct 2020 12:05:57 PDT (-0700), Atish Patra wrote:
RISC-V limits the physical memory size by -PAGE_OFFSET. Any memory beyond that size from DRAM start is unusable. Just remove any memblock pointing to those memory region without worrying about computing the maximum size.Signed-off-by: Atish Patra <atish.pa...@wdc.com> Reviewed-by: Mike Rapoport <r...@linux.ibm.com> --- Changes from v2->v3 Updated comment as per Mike's suggestion. --- arch/riscv/mm/init.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index ca03762a3733..564e0be677b7 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -146,8 +146,6 @@ static phys_addr_t dtb_early_pa __initdata; void __init setup_bootmem(void) { struct memblock_region *reg; - phys_addr_t mem_size = 0; - phys_addr_t total_mem = 0; phys_addr_t mem_start, end = 0; phys_addr_t vmlinux_end = __pa_symbol(&_end); phys_addr_t vmlinux_start = __pa_symbol(&_start); @@ -155,21 +153,18 @@ void __init setup_bootmem(void) /* Find the memory region containing the kernel */ for_each_memblock(memory, reg) { end = reg->base + reg->size; - if (!total_mem) + if (!mem_start) mem_start = reg->base; if (reg->base <= vmlinux_start && vmlinux_end <= end) BUG_ON(reg->size == 0); - total_mem = total_mem + reg->size; } /* - * Remove memblock from the end of usable area to the - * end of region + * The maximal physical memory size is -PAGE_OFFSET. + * Make sure that any memory beyond mem_start + (-PAGE_OFFSET) is removed + * as it is unusable by kernel. */ - mem_size = min(total_mem, (phys_addr_t)-PAGE_OFFSET); - if (mem_start + mem_size < end) - memblock_remove(mem_start + mem_size, - end - mem_start - mem_size); + memblock_enforce_memory_limit(mem_start - PAGE_OFFSET); /* Reserve from the start of the kernel to the end of the kernel */ memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
Thanks, this is on for-next.
