From 590e8a082a5772071d7bcfea2b8e5a2453cecad2 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com>
Date: Wed, 2 Jun 2021 16:37:01 +0100
Subject: CFI: Move function_nocfi() into compiler.h

Currently the common definition of function_nocfi() is provided by
<linux/mm.h>, and architectures are expected to provide a definition in
<asm/memory.h>. Due to header dependencies, this can make it hard to use
function_nocfi() in low-level headers.

As function_nocfi() has no dependency on any mm code, nor on any memory
definitions, it doesn't need to live in <linux/mm.h> or <asm/memory.h>.
Generally, it would make more sense for it to live in
<linux/compiler.h>, where an architecture can override it in
<asm/compiler.h>.

Move the definitions accordingly.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210602153701.35957-1-mark.rutland@arm.com
---
 include/linux/compiler.h | 10 ++++++++++
 include/linux/mm.h       | 10 ----------
 2 files changed, 10 insertions(+), 10 deletions(-)

(limited to 'include/linux')

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index df5b405e6305..099e529a5d25 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -213,6 +213,16 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 	__v;								\
 })
 
+/*
+ * With CONFIG_CFI_CLANG, the compiler replaces function addresses in
+ * instrumented C code with jump table addresses. Architectures that
+ * support CFI can define this macro to return the actual function address
+ * when needed.
+ */
+#ifndef function_nocfi
+#define function_nocfi(x) (x)
+#endif
+
 #endif /* __KERNEL__ */
 
 /*
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c274f75efcf9..b8c28b10f25d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -124,16 +124,6 @@ extern int mmap_rnd_compat_bits __read_mostly;
 #define lm_alias(x)	__va(__pa_symbol(x))
 #endif
 
-/*
- * With CONFIG_CFI_CLANG, the compiler replaces function addresses in
- * instrumented C code with jump table addresses. Architectures that
- * support CFI can define this macro to return the actual function address
- * when needed.
- */
-#ifndef function_nocfi
-#define function_nocfi(x) (x)
-#endif
-
 /*
  * To prevent common memory management code establishing
  * a zero page mapping on a read fault.
-- 
cgit