mm: add arch-independent testcases for RODATA

This patch makes arch-independent testcases for RODATA.  Both x86 and
x86_64 already have testcases for RODATA, But they are arch-specific
because using inline assembly directly.

And cacheflush.h is not a suitable location for rodata-test related
things.  Since they were in cacheflush.h, If someone change the state of
CONFIG_DEBUG_RODATA_TEST, It cause overhead of kernel build.

To solve the above issues, write arch-independent testcases and move it
to shared location.

[jinb.park7@gmail.com: fix config dependency]
  Link: http://lkml.kernel.org/r/20170209131625.GA16954@pjb1027-Latitude-E5410
Link: http://lkml.kernel.org/r/20170129105436.GA9303@pjb1027-Latitude-E5410
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 4 deletions

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 928d657de829..2b4b53e6793f 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -864,9 +864,6 @@ static noinline int do_test_wp_bit(void)
 	return flag;
 }
 
-const int rodata_test_data = 0xC3;
-EXPORT_SYMBOL_GPL(rodata_test_data);
-
 int kernel_set_to_readonly __read_mostly;
 
 void set_kernel_text_rw(void)
@@ -939,7 +936,6 @@ void mark_rodata_ro(void)
 	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
 	printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
 		size >> 10);
-	rodata_test();
 
 #ifdef CONFIG_CPA_DEBUG
 	printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);