Commit fc2fbc85 authored Dec 04, 2017 by Dave Hansen Committed by Ingo Molnar Dec 23, 2017

x86/mm/pti: Populate user PGD



In clone_pgd_range() copy the init user PGDs which cover the kernel half of
the address space, so a process has all the required kernel mappings
visible.

[ tglx: Split out from the big kaiser dump and folded Andys simplification ]

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent d9e9a641

arch/x86/include/asm/pgtable.h

+8 −1

Original line number	Diff line number	Diff line
		@@ -1120,6 +1120,13 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
		static inline void clone_pgd_range(pgd_t dst, pgd_t src, int count)
		{
		memcpy(dst, src, count * sizeof(pgd_t));
		#ifdef CONFIG_PAGE_TABLE_ISOLATION
		if (!static_cpu_has(X86_FEATURE_PTI))
		return;
		/* Clone the user space pgd as well */
		memcpy(kernel_to_user_pgdp(dst), kernel_to_user_pgdp(src),
		count * sizeof(pgd_t));
		#endif
		}

		#define PTE_SHIFT ilog2(PTRS_PER_PTE)