On Monday 20 February 2017 02:35 AM, Benjamin Herrenschmidt wrote:
On Sun, 2017-02-19 at 15:48 +0530, Aneesh Kumar K.V wrote:+#ifdef CONFIG_PPC_BOOK3S_64 + /* + * We need to make sure that for different page sizes reported by + * firmware we only add hugetlb support for page sizes that can be + * supported by linux page table layout. + * For now we have + * Radix: 2M + * Hash: 16M and 16G + */ + if (radix_enabled()) { + if (mmu_psize != MMU_PAGE_2M) + return -EINVAL; + } else { + if (mmu_psize != MMU_PAGE_16M && mmu_psize != MMU_PAGE_16G) + return -EINVAL; + }Hash could support others...
On book3s 64 ? I had the above within #ifdef.
Same with radix and PUD level pages.
Yes, but gigantic hugepage is not yet supported. Once we add that we will add MMU_PAGE_1G here.
Why do we need that ? Won't FW provide separate properties for hash and radix page sizes anyway ?
To avoid crashes like the one reported in the commit message due to buggy firmware ? Also It can serve as an easy way to understand what hugepage sizes are supported by different platforms. I am yet to figure out what the FSL_BOOK3E and PPC_8xx #ifdef above that hunk is all about. Having
the supported hugepage size clearly verified against makes it easy ? -aneesh
