[PATCH 09/15] compiler.h: Make __ADDRESSABLE() symbol truly unique

From: Peter Zijlstra
Date: Wed Jun 05 2019 - 09:28:01 EST

From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

The __ADDRESSABLE() macro uses the __LINE__ macro to create a temporary
symbol which has a unique name. However, if the macro is used multiple
times from within another macro, the line number will always be the
same, resulting in duplicate symbols.

Make the temporary symbols truly unique by using __UNIQUE_ID instead of

Cc: Julia Cartwright <julia@xxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
Cc: Edward Cree <ecree@xxxxxxxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jessica Yu <jeyu@xxxxxxxxxx>
Cc: David Laight <David.Laight@xxxxxxxxxx>
Cc: Nadav Amit <namit@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/8bc857824f82462a296a8a3c4913a11a7f801e74.1547073843.git.jpoimboe@xxxxxxxxxx
include/linux/compiler.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -294,7 +294,7 @@ unsigned long read_word_at_a_time(const
#define __ADDRESSABLE(sym) \
static void * __section(".discard.addressable") __used \
- __PASTE(__addressable_##sym, __LINE__) = (void *)&sym;
+ __UNIQUE_ID(__addressable_##sym) = (void *)&sym;

* offset_to_ptr - convert a relative memory offset to an absolute pointer