Re: [PATCH v2 2/2] powerpc/mm: Warn if W+X pages found on boot
From: Joel Stanley <joel@jms.id.au>
Date: 2019-05-03 00:40:49
On Thu, 2 May 2019 at 07:42, Russell Currey [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Implement code to walk all pages and warn if any are found to be both writable and executable. Depends on STRICT_KERNEL_RWX enabled, and is behind the DEBUG_WX config option. This only runs on boot and has no runtime performance implications. Very heavily influenced (and in some cases copied verbatim) from the ARM64 code written by Laura Abbott (thanks!), since our ptdump infrastructure is similar. Signed-off-by: Russell Currey <redacted> --- v2: A myriad of fixes and cleanups thanks to Christophe Leroy arch/powerpc/Kconfig.debug | 19 ++++++++++++++ arch/powerpc/include/asm/pgtable.h | 6 +++++ arch/powerpc/mm/pgtable_32.c | 3 +++ arch/powerpc/mm/pgtable_64.c | 3 +++ arch/powerpc/mm/ptdump/ptdump.c | 41 +++++++++++++++++++++++++++++- 5 files changed, 71 insertions(+), 1 deletion(-)diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug index 4e00cb0a5464..9e8bcddd8b8f 100644 --- a/arch/powerpc/Kconfig.debug +++ b/arch/powerpc/Kconfig.debug@@ -361,6 +361,25 @@ config PPC_PTDUMP If you are unsure, say N. +config PPC_DEBUG_WX
The other architectures call this DEBUG_WX, in case you wanted to name it the same.
+ bool "Warn on W+X mappings at boot" + select PPC_PTDUMP + help + Generate a warning if any W+X mappings are found at boot.