powerpc: Add framework for Kernel Userspace Protection

This patch adds a skeleton for Kernel Userspace Protection
functionnalities like Kernel Userspace Access Protection and Kernel
Userspace Execution Prevention

The subsequent implementation of KUAP for radix makes use of a MMU
feature in order to patch out assembly when KUAP is disabled or
unsupported. This won't work unless there's an entry point for KUP
support before the feature magic happens, so for PPC64 setup_kup() is
called early in setup.

On PPC32, feature_fixup() is done too early to allow the same.

Suggested-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

This commit is contained in:

Christophe Leroy

2019-04-18 16:51:18 +10:00

committed by

Michael Ellerman

parent 53a712bae5

commit 69795cabe4

4 changed files with 26 additions and 0 deletions

									
										arch/powerpc/mm/init-common.c
									
		+5
		
												View File
												
				@@ -24,6 +24,11 @@

				#include <linux/string.h>

				#include <asm/pgalloc.h>

				#include <asm/pgtable.h>

				#include <asm/kup.h>

				void __init setup_kup(void)

				{

				}

				#define CTOR(shift) static void ctor_##shift(void *addr) \

				{							\