x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option

This removes the CONFIG_DEBUG_RODATA option and makes it always enabled.

This simplifies the code and also makes it clearer that read-only mapped
memory is just as fundamental a security feature in kernel-space as it is
in user-space.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Brown <david.brown@linaro.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-arch <linux-arch@vger.kernel.org>
Link: http://lkml.kernel.org/r/1455748879-21872-4-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 0 insertions, 5 deletions

diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h
index c8cff75..61518cf 100644
--- a/arch/x86/include/asm/cacheflush.h
+++ b/arch/x86/include/asm/cacheflush.h
@@ -91,15 +91,10 @@ void clflush_cache_range(void *addr, unsigned int size);
 
 #define mmio_flush_range(addr, size) clflush_cache_range(addr, size)
 
-#ifdef CONFIG_DEBUG_RODATA
 extern const int rodata_test_data;
 extern int kernel_set_to_readonly;
 void set_kernel_text_rw(void);
 void set_kernel_text_ro(void);
-#else
-static inline void set_kernel_text_rw(void) { }
-static inline void set_kernel_text_ro(void) { }
-#endif
 
 #ifdef CONFIG_DEBUG_RODATA_TEST
 int rodata_test(void);