RISC-V: Remove any memblock representing unusable memory area

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.patra@wdc.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
This commit is contained in:
Atish Patra 2020-10-07 14:51:59 -07:00 committed by Palmer Dabbelt
parent 9d750c75bd
commit 1bd14a66ee
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@ -154,9 +154,8 @@ disable:
void __init setup_bootmem(void)
{
phys_addr_t mem_size = 0;
phys_addr_t total_mem = 0;
phys_addr_t mem_start, start, end = 0;
phys_addr_t mem_start = 0;
phys_addr_t start, end = 0;
phys_addr_t vmlinux_end = __pa_symbol(&_end);
phys_addr_t vmlinux_start = __pa_symbol(&_start);
u64 i;
@ -164,21 +163,18 @@ void __init setup_bootmem(void)
/* Find the memory region containing the kernel */
for_each_mem_range(i, &start, &end) {
phys_addr_t size = end - start;
if (!total_mem)
if (!mem_start)
mem_start = start;
if (start <= vmlinux_start && vmlinux_end <= end)
BUG_ON(size == 0);
total_mem = total_mem + 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);