Hi Toshi, On 2018/3/31 1:41, Kani, Toshi wrote: > On Fri, 2018-03-30 at 12:49 +0800, Yisheng Xie wrote: >> Zhou reported a bug on Hisilicon arm64 D06 platform with 64KB page size: > : >> The cause is the size of PCI IO resource is 32KB, which is 4K aligned but >> not 64KB aligned, so when do ioremap_pte_range(), its incoming end is not >> PAGE_ALIGN on 64KB page size system, but ioremap_pte_range increase the >> addr by PAGE_SIZE, which makes addr != end until trigger BUG_ON. >> >> This patch introduces pte_addr_end(addr, end) to resolve this problem, just >> as what pmd_addr_end do. When end is not PAGE_ALIGN, it will return end >> instead of addr + PAGE_SIZE, therefore ioremap_pte_range() can break out >> when real end is coming. > > ioremap_pte_range() assumes that addr and end are aligned by PAGE_SIZE. > While some improvement can be made in the range check and documentation, > I do not think it is safe for letting this library function to map > outside of a requested range blindly. > > Can you change the caller of ioremap_page_range() to align the request > by PAGE_SIZE so that the caller is aware of what it's asking for? Sure, as the name of ioremap_*page*_range(), the caller should make sure align the request by PAGE_SIZE. Thanks Yisheng > > Thanks, > -Toshi >
