linux-kernel - Re: commit 4dd1837d7589f468ed109556513f476e7a7f9121 breaks build

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Message-ID: <20161120172248.GW1041@n2100.armlinux.org.uk>
Date:   Sun, 20 Nov 2016 17:22:48 +0000
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Nicolas Pitre <nicolas.pitre@...aro.org>
Cc:     Tobias Jakobi <tjakobi@...h.uni-bielefeld.de>,
        linux-samsung-soc <linux-samsung-soc@...r.kernel.org>,
        viro@...iv.linux.org.uk,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: commit 4dd1837d7589f468ed109556513f476e7a7f9121 breaks build

On Sun, Nov 20, 2016 at 12:03:50PM -0500, Nicolas Pitre wrote:
> On Sun, 20 Nov 2016, Russell King - ARM Linux wrote:
> 
> > On Sun, Nov 20, 2016 at 01:56:16PM +0100, Tobias Jakobi wrote:
> > > Hey Russell,
> > > 
> > > thanks for the quick reply and looking into this!
> > > 
> > > Added Nicolas Pitre to Cc since the ksym trim stuff came from him.
> > 
> > Arnd's patch "kbuild: provide include/asm/asm-prototypes.h for ARM" fixes
> > it, but I think it's a mixture of fixes, and partially dependent on some
> > other patches.  I don't know what the status of his patch is, but my
> > feeling is that it consists of more than a single fix, and needs
> > splitting.  Certainly the asm-prototypes.h is not relevant to this
> > problem, but the rest of it seems to be.
> 
> Well... the problem for the current breakage was identified a while ago:
> 
> https://lkml.org/lkml/2016/2/10/686
> 
> I'm surprised that Al didn't fold my patch into his.  Now that this has 
> hit mainline, CONFIG_TRIM_UNUSED_KSYMS is now broken on ARM.
> 
> And I don't see how the asm-prototypes.h is going to fix it either (if 
> anything, at the moment it looks like it might be another source of 
> breakage).
> 
> So I think the folowing patch should go into mainline:

... which looks the same as Arnd's patch with the following changes:

- no asm-prototypes.h
- adding asm/export.h to each file using EXPORT_SYMBOL() instead of
   bitops.h
- not touching:
	arch/arm/lib/csumpartialcopy.S
	arch/arm/lib/csumpartialcopygeneric.S
	arch/arm/lib/csumpartialcopyuser.S

other than that, it's doing the same thing.

I think Arnd's changes to the csumpartial code are unnecessary, and
yours is, although larger, puts the asm/export.h include in the right
place.  So please drop yours into the patch system so we can move
forward fixing some of the problems created during the last merge
window.

> ----- >8
> >From 3225f625c116a350c54f361df491bf3e1c6d32b3 Mon Sep 17 00:00:00 2001
> From: Nicolas Pitre <nicolas.pitre@...aro.org>
> Date: Wed, 10 Feb 2016 17:40:04 -0500
> Subject: [PATCH] ARM: don't use assembler macro arguments with EXPORT_SYMBOL()
> 
> Committ 4dd1837d75 ("arm: move exports to definitions") added
> EXPORT_SYMBOL(\name) to bitops.h. Here \name is an assembler macro
> argument which is not subject to preprocessor substitutions. And the
> assembler doesn't handle preprocessor macros either. That has the effect
> of breaking CONFIG_TRIM_UNUSED_KSYMS=y.
> 
> Signed-off-by: Nicolas Pitre <nico@...aro.org>
> 
> diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h
> index df06638b32..7d807cfd8e 100644
> --- a/arch/arm/lib/bitops.h
> +++ b/arch/arm/lib/bitops.h
> @@ -1,6 +1,5 @@
>  #include <asm/assembler.h>
>  #include <asm/unwind.h>
> -#include <asm/export.h>
>  
>  #if __LINUX_ARM_ARCH__ >= 6
>  	.macro	bitop, name, instr
> @@ -26,7 +25,6 @@ UNWIND(	.fnstart	)
>  	bx	lr
>  UNWIND(	.fnend		)
>  ENDPROC(\name		)
> -EXPORT_SYMBOL(\name	)
>  	.endm
>  
>  	.macro	testop, name, instr, store
> @@ -57,7 +55,6 @@ UNWIND(	.fnstart	)
>  2:	bx	lr
>  UNWIND(	.fnend		)
>  ENDPROC(\name		)
> -EXPORT_SYMBOL(\name	)
>  	.endm
>  #else
>  	.macro	bitop, name, instr
> @@ -77,7 +74,6 @@ UNWIND(	.fnstart	)
>  	ret	lr
>  UNWIND(	.fnend		)
>  ENDPROC(\name		)
> -EXPORT_SYMBOL(\name	)
>  	.endm
>  
>  /**
> @@ -106,6 +102,5 @@ UNWIND(	.fnstart	)
>  	ret	lr
>  UNWIND(	.fnend		)
>  ENDPROC(\name		)
> -EXPORT_SYMBOL(\name	)
>  	.endm
>  #endif
> diff --git a/arch/arm/lib/changebit.S b/arch/arm/lib/changebit.S
> index f402786217..1cfdb138d2 100644
> --- a/arch/arm/lib/changebit.S
> +++ b/arch/arm/lib/changebit.S
> @@ -9,7 +9,10 @@
>   */
>  #include <linux/linkage.h>
>  #include <asm/assembler.h>
> +#include <asm/export.h>
>  #include "bitops.h"
>                  .text
>  
>  bitop	_change_bit, eor
> +
> +EXPORT_SYMBOL(_change_bit)
> diff --git a/arch/arm/lib/clearbit.S b/arch/arm/lib/clearbit.S
> index f6b75fb64d..e901ca5af0 100644
> --- a/arch/arm/lib/clearbit.S
> +++ b/arch/arm/lib/clearbit.S
> @@ -9,7 +9,10 @@
>   */
>  #include <linux/linkage.h>
>  #include <asm/assembler.h>
> +#include <asm/export.h>
>  #include "bitops.h"
>                  .text
>  
>  bitop	_clear_bit, bic
> +
> +EXPORT_SYMBOL(_clear_bit)
> diff --git a/arch/arm/lib/setbit.S b/arch/arm/lib/setbit.S
> index 618fedae4b..3c8b11240f 100644
> --- a/arch/arm/lib/setbit.S
> +++ b/arch/arm/lib/setbit.S
> @@ -9,7 +9,10 @@
>   */
>  #include <linux/linkage.h>
>  #include <asm/assembler.h>
> +#include <asm/export.h>
>  #include "bitops.h"
>  		.text
>  
>  bitop	_set_bit, orr
> +
> +EXPORT_SYMBOL(_set_bit)
> diff --git a/arch/arm/lib/testchangebit.S b/arch/arm/lib/testchangebit.S
> index 4becdc3a59..e3d19b87fb 100644
> --- a/arch/arm/lib/testchangebit.S
> +++ b/arch/arm/lib/testchangebit.S
> @@ -9,7 +9,10 @@
>   */
>  #include <linux/linkage.h>
>  #include <asm/assembler.h>
> +#include <asm/export.h>
>  #include "bitops.h"
>                  .text
>  
>  testop	_test_and_change_bit, eor, str
> +
> +EXPORT_SYMBOL(_test_and_change_bit)
> diff --git a/arch/arm/lib/testclearbit.S b/arch/arm/lib/testclearbit.S
> index 918841dcce..d247e6f70f 100644
> --- a/arch/arm/lib/testclearbit.S
> +++ b/arch/arm/lib/testclearbit.S
> @@ -9,7 +9,10 @@
>   */
>  #include <linux/linkage.h>
>  #include <asm/assembler.h>
> +#include <asm/export.h>
>  #include "bitops.h"
>                  .text
>  
>  testop	_test_and_clear_bit, bicne, strne
> +
> +EXPORT_SYMBOL(_test_and_clear_bit)
> diff --git a/arch/arm/lib/testsetbit.S b/arch/arm/lib/testsetbit.S
> index 8d1b2fe9e4..76800ff601 100644
> --- a/arch/arm/lib/testsetbit.S
> +++ b/arch/arm/lib/testsetbit.S
> @@ -9,7 +9,10 @@
>   */
>  #include <linux/linkage.h>
>  #include <asm/assembler.h>
> +#include <asm/export.h>
>  #include "bitops.h"
>                  .text
>  
>  testop	_test_and_set_bit, orreq, streq
> +
> +EXPORT_SYMBOL(_test_and_set_bit)

-- 
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