linux-kernel - Re: [PATCH] modpost: work correctly with tile coldtext sections

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Message-ID: <87wpyatjrh.fsf@rustcorp.com.au>
Date:	Thu, 09 Jul 2015 07:05:46 +0930
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Chris Metcalf <cmetcalf@...hip.com>,
	Quentin Casasnovas <quentin.casasnovas@...cle.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Mathias Krause <minipli@...glemail.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	linux-kernel@...r.kernel.org
Cc:	Chris Metcalf <cmetcalf@...hip.com>
Subject: Re: [PATCH] modpost: work correctly with tile coldtext sections

Chris Metcalf <cmetcalf@...hip.com> writes:
> The tilegx and tilepro compilers use .coldtext for their unlikely
> executed text section name, so an __attribute__((cold)) function
> will (when compiled with higher optimization levels) land in the
> the .coldtext section.
>
> Modify modpost to add .coldtext to the set of OTHER_TEXT_SECTIONS
> so we don't get warnings about referencing such a section in an
> __ex_table block, and then also modify arch/tile/lib/memcpy_user_64.c
> so that it uses plain ".coldtext" instead of ".coldtext.memcpy".
> The latter naming is a relic of an earlier use of -ffunction-sections,
> which we no longer use by default.
>
> Signed-off-by: Chris Metcalf <cmetcalf@...hip.com>
> ---
> Since this is a tile issue, should I push this through the tile tree?
> Or does someone want to take it into a tree for modpost?  Thanks.

Tile tree seems suitable, so:

Acked-by: Rusty Russell <rusty@...tcorp.com.au>

Thanks,
Rusty.

>
>  arch/tile/lib/memcpy_user_64.c | 4 ++--
>  scripts/mod/modpost.c          | 3 ++-
>  2 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/tile/lib/memcpy_user_64.c b/arch/tile/lib/memcpy_user_64.c
> index 88c7016492c4..97bbb6060b25 100644
> --- a/arch/tile/lib/memcpy_user_64.c
> +++ b/arch/tile/lib/memcpy_user_64.c
> @@ -28,7 +28,7 @@
>  #define _ST(p, inst, v)						\
>  	({							\
>  		asm("1: " #inst " %0, %1;"			\
> -		    ".pushsection .coldtext.memcpy,\"ax\";"	\
> +		    ".pushsection .coldtext,\"ax\";"	\
>  		    "2: { move r0, %2; jrp lr };"		\
>  		    ".section __ex_table,\"a\";"		\
>  		    ".align 8;"					\
> @@ -41,7 +41,7 @@
>  	({							\
>  		unsigned long __v;				\
>  		asm("1: " #inst " %0, %1;"			\
> -		    ".pushsection .coldtext.memcpy,\"ax\";"	\
> +		    ".pushsection .coldtext,\"ax\";"	\
>  		    "2: { move r0, %2; jrp lr };"		\
>  		    ".section __ex_table,\"a\";"		\
>  		    ".align 8;"					\
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 91ee1b2e0f9a..12d3db3bd46b 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -886,7 +886,8 @@ static void check_section(const char *modname, struct elf_info *elf,
>  #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
>  		".kprobes.text"
>  #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
> -		".fixup", ".entry.text", ".exception.text", ".text.*"
> +		".fixup", ".entry.text", ".exception.text", ".text.*", \
> +		".coldtext"
>  
>  #define INIT_SECTIONS      ".init.*"
>  #define MEM_INIT_SECTIONS  ".meminit.*"
> -- 
> 2.1.2
>
> --
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