arm64: add support to dump the kernel page tables

In a similar manner to arm, it's useful to be able to dump the page
tables to verify permissions and memory types. Add a debugfs file
to check the page tables.

Acked-by: Steve Capper <steve.capper@linaro.org>
Tested-by: Steve Capper <steve.capper@linaro.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
[will: s/BUFFERABLE/NORMAL-NC/]
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index 0a12933e50ed..5fdd6dce8061 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug
@@ -6,6 +6,18 @@ config FRAME_POINTER
         bool
         default y
 
+config ARM64_PTDUMP
+        bool "Export kernel pagetable layout to userspace via debugfs"
+        depends on DEBUG_KERNEL
+        select DEBUG_FS
+        help
+          Say Y here if you want to show the kernel pagetable layout in a
+          debugfs file. This information is only useful for kernel developers
+          who are working in architecture specific areas of the kernel.
+          It is probably not a good idea to enable this feature in a production
+          kernel.
+          If in doubt, say "N"
+
 config STRICT_DEVMEM
         bool "Filter access to /dev/mem"
         depends on MMU