2020-04-16 00:15:09

by Christophe Leroy

Subject: [PATCH] powerpc/uaccess: Don't set KUEP by default on book3s/32

On book3s/32, KUEP is an heavy process as it requires to
set/unset the NX bit in each of the 12 user segments
everytime the kernel is entered/exited from/to user space.

Don't select KUEP by default on book3s/32.

Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/platforms/Kconfig.cputype | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 0c7151c98b56..11412078e732 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -377,7 +377,7 @@ config PPC_HAVE_KUEP
config PPC_KUEP
bool "Kernel Userspace Execution Prevention"
depends on PPC_HAVE_KUEP
- default y
+ default y if !PPC_BOOK3S_32
help
Enable support for Kernel Userspace Execution Prevention (KUEP)

--
2.25.0

2020-06-09 05:31:08

by Michael Ellerman

Subject: Re: [PATCH] powerpc/uaccess: Don't set KUEP by default on book3s/32

On Wed, 15 Apr 2020 14:57:11 +0000 (UTC), Christophe Leroy wrote:
> On book3s/32, KUEP is an heavy process as it requires to
> set/unset the NX bit in each of the 12 user segments
> everytime the kernel is entered/exited from/to user space.
>
> Don't select KUEP by default on book3s/32.

Applied to powerpc/next.

[1/1] powerpc/uaccess: Don't set KUEP by default on book3s/32
https://git.kernel.org/powerpc/c/c3ba4dbbd1d05b49ec01efe098e0a78857d3ce22

cheers