Christophe Leroy ca8afd4046 powerpc/hugetlb: fix page rights verification in gup_hugepte() ... gup_hugepte() checks if pages are present and readable, and when 'write' is set, also checks if the pages are writable. Initially this was done by checking if _PAGE_PRESENT and _PAGE_READ were set. In addition, _PAGE_WRITE was verified for write accesses. The problem is that we have to handle the three following cases: 1/ The target defines __PAGE_READ and __PAGE_WRITE 2/ The target defines __PAGE_RW 3/ The target defines __PAGE_RO In case 1/, this is obvious In case 2/, __PAGE_READ is defined as 0 and __PAGE_WRITE as __PAGE_RW so it works as well. But in case 3, __PAGE_RW is defined as 0, which means __PAGE_WRITE is 0 and then the test returns true (page writable) in all cases. A first correction was attempted in commit 6b8cb66a6a ("powerpc: Fix usage of _PAGE_RO in hugepage"), but that fix is wrong: instead of checking that the page is writable when write is requested, it checks that the page is NOT writable when write is NOT requested. This patch adds a new pte_read() helper to check whether a page is readable or not. This avoids handling all possible cases in gup_hugepte(). Then gup_hugepte() is modified to use pte_present(), pte_read() and pte_write() instead of the raw flags. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>		2017-08-15 22:55:58 +10:00
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32	powerpc/mm: declare some local functions static	2017-08-15 22:55:57 +10:00
64	powerpc/mm/book(e)(3s)/64: Add page table accounting	2017-06-05 19:03:10 +10:00
pgalloc.h	powerpc/mm: Copy pgalloc (part 2)	2016-05-11 21:53:49 +10:00
pgtable.h	powerpc/hugetlb: fix page rights verification in gup_hugepte()	2017-08-15 22:55:58 +10:00
pte-book3e.h	powerpc/booke: Move nohash headers	2015-12-14 15:19:09 +11:00