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Commit 76a7d7cf authored by Sami Tolvanen's avatar Sami Tolvanen Committed by Alistair Strachan
Browse files

ANDROID: init: ensure initcall ordering with LTO 



With LTO, LLVM sorts initcalls in a single translation unit alphabetically
based on the name of the function (or actually, the variable stored in
the initcall section). Use __COUNTER__ in the variable name in an attempt
to preserve the intended order.

In addition, LTO requires all initcall variables to have unique names. Use
__LINE__ in the name to reduce the chance of name collisions.

Bug: 62093296
Bug: 67506682
Change-Id: I4fa3cb93cba967a1440ac53328eb6b8ac649ff36
Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
parent e66e4ad1

include/linux/init.h

+16 −2
Original line number Diff line number Diff line
@@ -167,6 +167,20 @@ extern bool initcall_debug; 


#ifndef __ASSEMBLY__



#ifdef CONFIG_LTO_CLANG

  /*

   * Use __COUNTER__ prefix in the variable to help ensure ordering

   * inside a compilation unit that defines multiple initcalls, and

   * __LINE__ to help prevent naming collisions.

   */

  #define ___initcall_name2(c, l, fn, id) __initcall_##c##_##l##_##fn##id

  #define ___initcall_name1(c, l, fn, id) ___initcall_name2(c, l, fn, id)

  #define __initcall_name(fn, id) \

		___initcall_name1(__COUNTER__, __LINE__, fn, id)

#else

  #define __initcall_name(fn, id) 	__initcall_##fn##id

#endif



/*

 * initcalls are now grouped by functionality into separate

 * subsections. Ordering inside the subsections is determined
@@ -187,12 +201,12 @@ extern bool initcall_debug; 
#define ___define_initcall(fn, id, __sec)			\

	__ADDRESSABLE(fn)					\

	asm(".section	\"" #__sec ".init\", \"a\"	\n"	\

	"__initcall_" #fn #id ":			\n"	\

	__stringify(__initcall_name(fn, id)) ":		\n"	\

	    ".long	" #fn " - .			\n"	\

	    ".previous					\n");

#else

#define ___define_initcall(fn, id, __sec) \

	static initcall_t __initcall_##fn##id __used \

	static initcall_t __initcall_name(fn, id) __used \

		__attribute__((__section__(#__sec ".init"))) = fn;

#endif