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From: "Luis R. Rodriguez" <mcgrof@kernel.org>
To: andi@firstfloor.org
Cc: hpa@zytor.com, linux-kernel@vger.kernel.org, x86@kernel.org,
	bp@alien8.de, luto@amacapital.net,
	"Luis R. Rodriguez" <mcgrof@kernel.org>
Subject: [PATCH v2] x86: remove LTO_REFERENCE_INITCALL()
Date: Thu,  7 Jul 2016 09:01:49 -0700	[thread overview]
Message-ID: <1467907309-6678-1-git-send-email-mcgrof@kernel.org> (raw)
In-Reply-To: <20160707015500.GQ13997@two.firstfloor.org>

The setup for LTO never made it upstream, and although this has
some users, this is now really old stuff for a gcc 4.7 LTO problem.
We know that at least LTO_REFERENCE_INITCALL() work around can
be removed if LTO is not supported on v4.7 anymore.

As per Andi the DISABLE_LTO and LTO_CFLAGS are still neeeded though.

Tested-by: 0-day
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
---
 include/linux/init.h | 20 +-------------------
 1 file changed, 1 insertion(+), 19 deletions(-)

diff --git a/include/linux/init.h b/include/linux/init.h
index 1e5c131d5c9a..aa662ad80d9c 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -151,23 +151,6 @@ extern bool initcall_debug;
 
 #ifndef __ASSEMBLY__
 
-#ifdef CONFIG_LTO
-/* Work around a LTO gcc problem: when there is no reference to a variable
- * in a module it will be moved to the end of the program. This causes
- * reordering of initcalls which the kernel does not like.
- * Add a dummy reference function to avoid this. The function is
- * deleted by the linker.
- */
-#define LTO_REFERENCE_INITCALL(x) \
-	; /* yes this is needed */			\
-	static __used __exit void *reference_##x(void)	\
-	{						\
-		return &x;				\
-	}
-#else
-#define LTO_REFERENCE_INITCALL(x)
-#endif
-
 /* initcalls are now grouped by functionality into separate 
  * subsections. Ordering inside the subsections is determined
  * by link order. 
@@ -180,8 +163,7 @@ extern bool initcall_debug;
 
 #define __define_initcall(fn, id) \
 	static initcall_t __initcall_##fn##id __used \
-	__attribute__((__section__(".initcall" #id ".init"))) = fn; \
-	LTO_REFERENCE_INITCALL(__initcall_##fn##id)
+	__attribute__((__section__(".initcall" #id ".init"))) = fn;
 
 /*
  * Early initcalls run before initializing SMP.
-- 
2.8.4

  reply	other threads:[~2016-07-07 16:02 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-23 23:34 Is LTO_REFERENCE_INITCALL() still needed? Luis R. Rodriguez
2016-06-24 21:07 ` Andi Kleen
2016-06-28  0:47   ` Luis R. Rodriguez
2016-07-07  0:22     ` [PATCH] x86: remove LTO flags Luis R. Rodriguez
2016-07-07  1:55       ` Andi Kleen
2016-07-07 16:01         ` Luis R. Rodriguez [this message]
2016-07-07 16:32           ` [PATCH v2] x86: remove LTO_REFERENCE_INITCALL() Andi Kleen
2016-07-21 19:00             ` Luis R. Rodriguez

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