[PATCH 0/2] Bugs fix up for DEBUG_WX

[PATCH 0/2] Bugs fix up for DEBUG_WX

[Zong Li]

These patches fix some bugs of DEBUG_WX. The first one is removing the
name of arm64 page talbe use. The second one is adding MMU dependency,
otherwise, it causes build error on NOMMU system, which reported by
kbuild test.

Zong Li (2):
  mm: remove the specific name of arm64
  mm: add MMU dependency for DEBUG_WX

 mm/Kconfig.debug | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

-- 
2.26.2

[PATCH 1/2] mm: remove the specific name of arm64

[Zong Li]

UXN is the name of arm64 page-table descriptors.

Signed-off-by: Zong Li <zong.li@sifive.com>
CC: Will Deacon <will@kernel.org>
---
 mm/Kconfig.debug | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index e19f94c6df90..b8cbe035247f 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -130,8 +130,6 @@ config DEBUG_WX
 
 	  This is useful for discovering cases where the kernel is leaving W+X
 	  mappings after applying NX, as such mappings are a security risk.
-	  This check also includes UXN, which should be set on all kernel
-	  mappings.
 
 	  Look for a message in dmesg output like this:
 
-- 
2.26.2

[PATCH 2/2] mm: add MMU dependency for DEBUG_WX

[Zong Li]

DEBUG_WX should be enabled on MMU system. It had got build error when
enabling DEBUG_WX on NOMMU.

Signed-off-by: Zong Li <zong.li@sifive.com>
Reported-by: kbuild test robot <lkp@intel.com>
---
 mm/Kconfig.debug | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index b8cbe035247f..2409f7fc1567 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -124,6 +124,7 @@ config ARCH_HAS_DEBUG_WX
 config DEBUG_WX
 	bool "Warn on W+X mappings at boot"
 	depends on ARCH_HAS_DEBUG_WX
+	depends on MMU
 	select PTDUMP_CORE
 	help
 	  Generate a warning if any W+X mappings are found at boot.
-- 
2.26.2

Re: [PATCH 1/2] mm: remove the specific name of arm64

[Will Deacon]

On Mon, May 11, 2020 at 02:28:19PM +0800, Zong Li wrote:
> UXN is the name of arm64 page-table descriptors.
> 
> Signed-off-by: Zong Li <zong.li@sifive.com>
> CC: Will Deacon <will@kernel.org>
> ---
>  mm/Kconfig.debug | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
> index e19f94c6df90..b8cbe035247f 100644
> --- a/mm/Kconfig.debug
> +++ b/mm/Kconfig.debug
> @@ -130,8 +130,6 @@ config DEBUG_WX
>  
>  	  This is useful for discovering cases where the kernel is leaving W+X
>  	  mappings after applying NX, as such mappings are a security risk.
> -	  This check also includes UXN, which should be set on all kernel
> -	  mappings.
>  
>  	  Look for a message in dmesg output like this:

Acked-by: Will Deacon <will@kernel.org>

The commit message needs help, but I'm assuming Andrew will just fold this
into the other patch so it doesn't matter.

Will