Re: Compiling with old gcc breaks when CONFIG_RETPOLINE is off

From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: zhenzhong.duan@oracle.com
Cc: Meelis Roos <mroos@linux.ee>,
	Thomas Gleixner <tglx@linutronix.de>,
	David Woodhouse <dwmw@amazon.co.uk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Compiling with old gcc breaks when CONFIG_RETPOLINE is off
Date: Wed, 5 Dec 2018 12:00:41 +0900	[thread overview]
Message-ID: <CAK7LNASqynzpsrx1CCZmaSGK2K6owwkR0=FugkqDJVLDyQ7Q0w@mail.gmail.com> (raw)
In-Reply-To: <3f72d5fa-cfed-e1a0-4f6c-90f8d1de1ace@oracle.com>

On Wed, Dec 5, 2018 at 10:31 AM Zhenzhong Duan
<zhenzhong.duan@oracle.com> wrote:
>
> Hi Meelis,
>
> Could you try below change? It force syncconfig for  any 'make *config"
>
> so that autoconf.h and auto.conf are always updated.

NACK.

syncconfig should happen only when you are about to build something.

This patch let "make *config" touch include/config/* around
unnecessarily.

> diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
> index 98e0c7a..802875b 100644
> --- a/scripts/kconfig/conf.c
> +++ b/scripts/kconfig/conf.c
> @@ -38,7 +38,7 @@ enum input_mode {
>
>   static int indent = 1;
>   static int tty_stdio;
> -static int sync_kconfig;
> +static int sync_kconfig = 1;
>   static int conf_cnt;
>   static char line[PATH_MAX];
>   static struct menu *rootEntry;
> @@ -506,11 +506,11 @@ int main(int ac, char **av)
>                           * Suppress distracting "configuration written
> to ..."
>                           */
>                          conf_set_message_callback(NULL);
> -                       sync_kconfig = 1;
>                          break;
>                  case defconfig:
>                  case savedefconfig:
>                          defconfig_file = optarg;
> +                       sync_kconfig = 0;
>                          break;
>                  case randconfig:
>                  {
> @@ -537,13 +537,15 @@ int main(int ac, char **av)
>                          srand(seed);
>                          break;
>                  }
> +               case listnewconfig:
> +                       sync_kconfig = 0;
> +                       /* fall through */
>                  case oldaskconfig:
>                  case oldconfig:
>                  case allnoconfig:
>                  case allyesconfig:
>                  case allmodconfig:
>                  case alldefconfig:
> -               case listnewconfig:
>                  case olddefconfig:
>                          break;
>                  case '?':
>
> Thanks
>
> Zhenzhong
>
> On 2018/12/4 17:58, Meelis Roos wrote:
> > Just tried 4.20-rc5 on an old K6-2 PC with gcc 5.3.1, got an error
> > about non-retpoline compiler,
> > turned CONFIG_RETPOLINE off and retried.
> >
> > To my surprise, compilation still breaks with
> > arch/x86/Makefile:224: *** You are building kernel with non-retpoline
> > compiler, please update your compiler..  Stop.
> >
> > As I read the Makefile, it should error only when CONFIG_RETPOLINE is
> > enabled, but it still breaks.
> >
> > $ grep -r CONFIG_RETPOLINE .config
> > # CONFIG_RETPOLINE is not set
> >
> > $ grep -r CONFIG_RETPOLINE include/
> > include/generated/autoconf.h:#define CONFIG_RETPOLINE 1
> > include/config/auto.conf:CONFIG_RETPOLINE=y
> >
> > So the headers have not been updated yet, maybe?
> >

-- 
Best Regards
Masahiro Yamada