On the 8xx, there is absolutely no runtime impact with KUEP. Protection
against execution of user code in kernel mode is set up at boot time
by configuring the groups with contain all user pages as having swapped
protection rights, in extenso EX for user and NA for supervisor.
Configure KUEP at startup and force selection of CONFIG_PPC_KUEP.
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
arch/powerpc/include/asm/nohash/32/mmu-8xx.h | 6 ++----
arch/powerpc/mm/nohash/8xx.c | 5 -----
arch/powerpc/platforms/Kconfig.cputype | 1 +
3 files changed, 3 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
index 997cec973406..0e93a4728c9e 100644
--- a/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/mmu-8xx.h
@@ -39,12 +39,10 @@
* 0 => Kernel => 11 (all accesses performed according as user iaw page
definition)
* 1 => Kernel+Accessed => 01 (all accesses performed according to page
definition)
* 2 => User => 11 (all accesses performed according as user iaw page
definition)
- * 3 => User+Accessed => 00 (all accesses performed as supervisor iaw page
definition) for INIT
- * => 10 (all accesses performed according to swaped page
definition) for KUEP
+ * 3 => User+Accessed => 10 (all accesses performed according to swaped page
definition) for KUEP
* 4-15 => Not Used
*/
-#define MI_APG_INIT 0xdc000000
-#define MI_APG_KUEP 0xde000000
+#define MI_APG_INIT 0xde000000
/* The effective page number register. When read, contains the information
* about the last instruction TLB miss. When MI_RPN is written, bits in
diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
index baa1f8a40af8..e878e8124ee6 100644
--- a/arch/powerpc/mm/nohash/8xx.c
+++ b/arch/powerpc/mm/nohash/8xx.c
@@ -215,12 +215,7 @@ void __init setup_initial_memory_limit(phys_addr_t
first_memblock_base,
#ifdef CONFIG_PPC_KUEP
void setup_kuep(bool disabled)
{
- if (disabled)
- return;
-
pr_info("Activating Kernel Userspace Execution Prevention\n");
-
- mtspr(SPRN_MI_AP, MI_APG_KUEP);
}
#endif
diff --git a/arch/powerpc/platforms/Kconfig.cputype
b/arch/powerpc/platforms/Kconfig.cputype
index a208997ade88..66650ec1c7e6 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -43,6 +43,7 @@ config PPC_8xx
select ARCH_SUPPORTS_HUGETLBFS
select FSL_SOC
select PPC_HAVE_KUEP
+ select PPC_KUEP
select PPC_HAVE_KUAP
select HAVE_ARCH_VMAP_STACK
select HUGETLBFS
--
2.31.1
