x86: add testcases for RODATA and NX protections/attributes

Latest update; I now have 4 NX tests, but 2 fail so they're #if 0'd.
I also cleaned up the NX test code quite a bit, and got rid of the ugly
exception table sorting stuff.

From: Arjan van de Ven <arjan@linux.intel.com>

This patch adds testcases for the CONFIG_DEBUG_RODATA configuration option
as well as the NX CPU feature/mappings. Both testcases can move to tests/
once that patch gets merged into mainline.
(I'm half considering moving the rodata test into mm/init.c but I'll
wait with that until init.c is unified)

As part of this I had to fix a not-quite-right alignment in the vmlinux.lds.h
for the RODATA sections, which lead to 1 page less being marked read only.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 8 insertions, 0 deletions

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 76df771be585..f784d2f34149 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -184,6 +184,7 @@
                 VMLINUX_SYMBOL(__start___param) = .;                    \
                 *(__param)                                              \
                 VMLINUX_SYMBOL(__stop___param) = .;                     \
+                . = ALIGN((align));                                     \
                 VMLINUX_SYMBOL(__end_rodata) = .;                       \
         }                                                               \
         . = ALIGN((align));
diff --git a/include/asm-x86/cacheflush.h b/include/asm-x86/cacheflush.h
index 157da0206ccc..3e74aff90809 100644
--- a/include/asm-x86/cacheflush.h
+++ b/include/asm-x86/cacheflush.h
@@ -47,5 +47,12 @@ void clflush_cache_range(void *addr, int size);
 #ifdef CONFIG_DEBUG_RODATA
 void mark_rodata_ro(void);
 #endif
+#ifdef CONFIG_DEBUG_RODATA_TEST
+void rodata_test(void);
+#else
+static inline void rodata_test(void)
+{
+}
+#endif
 
 #endif