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![]() In sparse vmemmap model, the virtual address of vmemmap is calculated as:
((struct page *)VMEMMAP_START - (phys_ram_base >> PAGE_SHIFT)).
And the struct page's va can be calculated with an offset:
(vmemmap + (pfn)).
However, when initializing struct pages, kernel actually starts from the
first page from the same section that phys_ram_base belongs to. If the
first page's physical address is not (phys_ram_base >> PAGE_SHIFT), then
we get an va below VMEMMAP_START when calculating va for it's struct page.
For example, if phys_ram_base starts from 0x82000000 with pfn 0x82000, the
first page in the same section is actually pfn 0x80000. During
init_unavailable_range(), we will initialize struct page for pfn 0x80000
with virtual address ((struct page *)VMEMMAP_START - 0x2000), which is
below VMEMMAP_START as well as PCI_IO_END.
This commit fixes this bug by introducing a new variable
'vmemmap_start_pfn' which is aligned with memory section size and using
it to calculate vmemmap address instead of phys_ram_base.
Fixes:
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.. | ||
cache-ops.c | ||
cacheflush.c | ||
context.c | ||
dma-noncoherent.c | ||
extable.c | ||
fault.c | ||
hugetlbpage.c | ||
init.c | ||
kasan_init.c | ||
Makefile | ||
pageattr.c | ||
pgtable.c | ||
physaddr.c | ||
pmem.c | ||
ptdump.c | ||
tlbflush.c |