Christophe Leroy b6cb20fdc2 powerpc/book3e: Fix set_memory_x() and set_memory_nx() ... set_memory_x() calls pte_mkexec() which sets _PAGE_EXEC. set_memory_nx() calls pte_exprotec() which clears _PAGE_EXEC. Book3e has 2 bits, UX and SX, which defines the exec rights resp. for user (PR=1) and for kernel (PR=0). _PAGE_EXEC is defined as UX only. An executable kernel page is set with either _PAGE_KERNEL_RWX or _PAGE_KERNEL_ROX, which both have SX set and UX cleared. So set_memory_nx() call for an executable kernel page does nothing because UX is already cleared. And set_memory_x() on a non-executable kernel page makes it executable for the user and keeps it non-executable for kernel. Also, pte_exec() always returns 'false' on kernel pages, because it checks _PAGE_EXEC which doesn't include SX, so for instance the W+X check doesn't work. To fix this: - change tlb_low_64e.S to use _PAGE_BAP_UX instead of _PAGE_USER - sets both UX and SX in _PAGE_EXEC so that pte_exec() returns true whenever one of the two bits is set and pte_exprotect() clears both bits. - Define a book3e specific version of pte_mkexec() which sets either SX or UX based on UR. Fixes: 1f9ad21c3b ("powerpc/mm: Implement set_memory() routines") Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/c41100f9c144dc5b62e5a751b810190c6b5d42fd.1635226743.git.christophe.leroy@csgroup.eu		2021-10-28 00:41:29 +11:00
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pgalloc.h	powerpc: add support for folded p4d page tables	2020-06-04 19:06:21 -07:00
pgtable-4k.h	mm: rename p4d_page_vaddr to p4d_pgtable and make it return pud_t *	2021-07-08 11:48:22 -07:00
pgtable.h	powerpc/book3e: Fix set_memory_x() and set_memory_nx()	2021-10-28 00:41:29 +11:00