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* Re: [PATCH] x86/config: Make the x86 defconfigs a bit more usable
       [not found]                 ` <YkHXQTKImf7Wr+Sk@dev-arch.thelio-3990X>
@ 2022-09-02  8:50                   ` Ingo Molnar
  2022-09-02  9:18                     ` Masahiro Yamada
  0 siblings, 1 reply; 6+ messages in thread
From: Ingo Molnar @ 2022-09-02  8:50 UTC (permalink / raw)
  To: Nathan Chancellor, Masahiro Yamada, linux-kbuild
  Cc: Linus Torvalds, Borislav Petkov, Linux Kernel Mailing List,
	Peter Zijlstra, Will Deacon, Waiman Long, Boqun Feng,
	Thomas Gleixner, Andrew Morton, Sebastian Andrzej Siewior


* Nathan Chancellor <nathan@kernel.org> wrote:

> On Sun, Mar 27, 2022 at 09:03:14PM +0200, Ingo Molnar wrote:
> > Yeah, good catch! ...
> > 
> > I use defconfigs by explicitly adding in the architecture:
> > 
> >   kepler:~/tip> make ARCH=i386 defconfig
> > 
> >   kepler:~/tip> kconfig-arch
> >   i386
> > 
> > ... so never I noticed this bug.
> 
> Ah, good point!
> 
> > I fixed this in the latest version (attached).
> > 
> > Arguably 'make ARCH=i386 savedefconfig' should preserve this, so that 
> > refreshing defconfigs on bi-arch architectures is idempotent, but that's no 
> > excuse to regress the existing defconfig behavior.
> 
> Hmmm, I thought that it would, but I think the behavior of savedefconfig
> is actually correct with regards to how it handles CONFIG_64BIT in the
> presence of an explicit ARCH value, based on how CONFIG_64BIT is
> defined:
> 
> config 64BIT
> 	bool "64-bit kernel" if "$(ARCH)" = "x86"
> 	default "$(ARCH)" != "i386"
> 	help
> 	  Say yes to build a 64-bit kernel - formerly known as x86_64
> 	  Say no to build a 32-bit kernel - formerly known as i386
> 
> As the default is no when ARCH == i386 and there is no prompt in that
> situation, "# CONFIG_64BIT is not set" gets dropped, as that is the
> default. Using savedefconfig without the ARCH variable would do the
> right thing.
> 
> I tried playing around with these Kconfig symbols to see if I could get
> something that would work for savedefconfig with or without ARCH, but I
> could not really come up with anything. I did not try super hard though,
> it might still be possible.

Unfortunately, even without the ARCH=i386 'make savedefconfig' doesn't seem 
to be doing the right thing & is dropping the '# CONFIG_64BIT is not set' 
line:

 kepler:~/tip> make ARCH=i386 defconfig
 *** Default configuration is based on 'i386_defconfig'
 #
 # configuration written to .config
 #
 kepler:~/tip> make savedefconfig
 kepler:~/tip> diff -up arch/x86/configs/i386_defconfig defconfig
 --- arch/x86/configs/i386_defconfig	2022-09-02 10:45:43.117430882 +0200
 +++ defconfig	2022-09-02 10:46:56.663864901 +0200
 @@ -282,4 +282,3 @@ CONFIG_PROVIDE_OHCI1394_DMA_INIT=y
  CONFIG_EARLY_PRINTK_DBGP=y
  CONFIG_DEBUG_BOOT_PARAMS=y
  CONFIG_UNWINDER_FRAME_POINTER=y
 -# CONFIG_64BIT is not set
 kepler:~/tip> 

This is annoying in that every time I modify the i386 defconfig and use 
'make savedefconfig', I have to manually revert that change ...

This reduces the usability of 'make savedefconfig' quite a bit.

Maybe Masahiro-san can tell me how I'm doing this wrong?

Thanks,

	Ingo

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] x86/config: Make the x86 defconfigs a bit more usable
  2022-09-02  8:50                   ` [PATCH] x86/config: Make the x86 defconfigs a bit more usable Ingo Molnar
@ 2022-09-02  9:18                     ` Masahiro Yamada
  2022-09-04  9:48                       ` Ingo Molnar
  0 siblings, 1 reply; 6+ messages in thread
From: Masahiro Yamada @ 2022-09-02  9:18 UTC (permalink / raw)
  To: Ingo Molnar
  Cc: Nathan Chancellor, Linux Kbuild mailing list, Linus Torvalds,
	Borislav Petkov, Linux Kernel Mailing List, Peter Zijlstra,
	Will Deacon, Waiman Long, Boqun Feng, Thomas Gleixner,
	Andrew Morton, Sebastian Andrzej Siewior

On Fri, Sep 2, 2022 at 5:50 PM Ingo Molnar <mingo@kernel.org> wrote:
>
>
> * Nathan Chancellor <nathan@kernel.org> wrote:
>
> > On Sun, Mar 27, 2022 at 09:03:14PM +0200, Ingo Molnar wrote:
> > > Yeah, good catch! ...
> > >
> > > I use defconfigs by explicitly adding in the architecture:
> > >
> > >   kepler:~/tip> make ARCH=i386 defconfig
> > >
> > >   kepler:~/tip> kconfig-arch
> > >   i386
> > >
> > > ... so never I noticed this bug.
> >
> > Ah, good point!
> >
> > > I fixed this in the latest version (attached).
> > >
> > > Arguably 'make ARCH=i386 savedefconfig' should preserve this, so that
> > > refreshing defconfigs on bi-arch architectures is idempotent, but that's no
> > > excuse to regress the existing defconfig behavior.
> >
> > Hmmm, I thought that it would, but I think the behavior of savedefconfig
> > is actually correct with regards to how it handles CONFIG_64BIT in the
> > presence of an explicit ARCH value, based on how CONFIG_64BIT is
> > defined:
> >
> > config 64BIT
> >       bool "64-bit kernel" if "$(ARCH)" = "x86"
> >       default "$(ARCH)" != "i386"
> >       help
> >         Say yes to build a 64-bit kernel - formerly known as x86_64
> >         Say no to build a 32-bit kernel - formerly known as i386
> >
> > As the default is no when ARCH == i386 and there is no prompt in that
> > situation, "# CONFIG_64BIT is not set" gets dropped, as that is the
> > default. Using savedefconfig without the ARCH variable would do the
> > right thing.
> >
> > I tried playing around with these Kconfig symbols to see if I could get
> > something that would work for savedefconfig with or without ARCH, but I
> > could not really come up with anything. I did not try super hard though,
> > it might still be possible.
>
> Unfortunately, even without the ARCH=i386 'make savedefconfig' doesn't seem
> to be doing the right thing & is dropping the '# CONFIG_64BIT is not set'
> line:


Oh, really?

Without ARCH=i386, it works correctly for me.



masahiro@zoe:~/ref/linux$ make i386_defconfig savedefconfig
#
# No change to .config
#
masahiro@zoe:~/ref/linux$ grep CONFIG_64BIT defconfig
# CONFIG_64BIT is not set




I guess you gave ARCH=i386 somewhere.







>  kepler:~/tip> make ARCH=i386 defconfig
>  *** Default configuration is based on 'i386_defconfig'
>  #
>  # configuration written to .config
>  #
>  kepler:~/tip> make savedefconfig
>  kepler:~/tip> diff -up arch/x86/configs/i386_defconfig defconfig
>  --- arch/x86/configs/i386_defconfig    2022-09-02 10:45:43.117430882 +0200
>  +++ defconfig  2022-09-02 10:46:56.663864901 +0200
>  @@ -282,4 +282,3 @@ CONFIG_PROVIDE_OHCI1394_DMA_INIT=y
>   CONFIG_EARLY_PRINTK_DBGP=y
>   CONFIG_DEBUG_BOOT_PARAMS=y
>   CONFIG_UNWINDER_FRAME_POINTER=y
>  -# CONFIG_64BIT is not set
>  kepler:~/tip>
>
> This is annoying in that every time I modify the i386 defconfig and use
> 'make savedefconfig', I have to manually revert that change ...
>
> This reduces the usability of 'make savedefconfig' quite a bit.
>
> Maybe Masahiro-san can tell me how I'm doing this wrong?
>
> Thanks,
>
>         Ingo



--
Best Regards
Masahiro Yamada

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] x86/config: Make the x86 defconfigs a bit more usable
  2022-09-02  9:18                     ` Masahiro Yamada
@ 2022-09-04  9:48                       ` Ingo Molnar
  2022-09-05  2:16                         ` Masahiro Yamada
  0 siblings, 1 reply; 6+ messages in thread
From: Ingo Molnar @ 2022-09-04  9:48 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: Nathan Chancellor, Linux Kbuild mailing list, Linus Torvalds,
	Borislav Petkov, Linux Kernel Mailing List, Peter Zijlstra,
	Will Deacon, Waiman Long, Boqun Feng, Thomas Gleixner,
	Andrew Morton, Sebastian Andrzej Siewior


* Masahiro Yamada <masahiroy@kernel.org> wrote:

> > Unfortunately, even without the ARCH=i386 'make savedefconfig' doesn't 
> > seem to be doing the right thing & is dropping the '# CONFIG_64BIT is 
> > not set' line:
> 
> 
> Oh, really?
> 
> Without ARCH=i386, it works correctly for me.
> 
> 
> 
> masahiro@zoe:~/ref/linux$ make i386_defconfig savedefconfig
> #
> # No change to .config
> #
> masahiro@zoe:~/ref/linux$ grep CONFIG_64BIT defconfig
> # CONFIG_64BIT is not set

Yeah, so why do these two seemingly identical commands produce two 
different .config's:

  $ make ARCH=i386 defconfig
  *** Default configuration is based on 'i386_defconfig'

  $ make i386_defconfig

?

Basically the canonical way to generate a defconfig is to provide an ARCH, 
then use the common 'defconfig' target:

   make ARCH=i386      defconfig
   make ARCH=x86       defconfig
   make ARCH=arm       defconfig
   make ARCH=arm64     defconfig
   make ARCH=powerpc   defconfig
   make ARCH=s390      defconfig
   make ARCH=sparc     defconfig
   make ARCH=sparc64   defconfig
   ...

This is what my build test scripts are using to quick-test cross-arch 
builds. It's a straightforward way to generate defconfigs without knowing 
the details of the myriads of random defconfig targets some architectures 
have, such as:

  kepler:~/tip> ls arch/arm/configs/
  am200epdkit_defconfig     gemini_defconfig         multi_v5_defconfig    s5pv210_defconfig
  aspeed_g4_defconfig       h3600_defconfig          multi_v7_defconfig    sama5_defconfig
  aspeed_g5_defconfig       h5000_defconfig          mv78xx0_defconfig     sama7_defconfig
  assabet_defconfig         hackkit_defconfig        mvebu_v5_defconfig    shannon_defconfig
  at91_dt_defconfig         hisi_defconfig           mvebu_v7_defconfig    shmobile_defconfig
  axm55xx_defconfig         imxrt_defconfig          mxs_defconfig         simpad_defconfig
  badge4_defconfig          imx_v4_v5_defconfig      neponset_defconfig    socfpga_defconfig
  bcm2835_defconfig         imx_v6_v7_defconfig      netwinder_defconfig   sp7021_defconfig
  cerfcube_defconfig        integrator_defconfig     nhk8815_defconfig     spear13xx_defconfig
  clps711x_defconfig        iop32x_defconfig         omap1_defconfig       spear3xx_defconfig
  cm_x300_defconfig         ixp4xx_defconfig         omap2plus_defconfig   spear6xx_defconfig
  cns3420vb_defconfig       jornada720_defconfig     orion5x_defconfig     spitz_defconfig
  colibri_pxa270_defconfig  keystone_defconfig       oxnas_v6_defconfig    stm32_defconfig
  colibri_pxa300_defconfig  lart_defconfig           palmz72_defconfig     sunxi_defconfig
  collie_defconfig          lpc18xx_defconfig        pcm027_defconfig      tct_hammer_defconfig
  corgi_defconfig           lpc32xx_defconfig        pleb_defconfig        tegra_defconfig
  davinci_all_defconfig     lpd270_defconfig         pxa168_defconfig      trizeps4_defconfig
  dove_defconfig            lubbock_defconfig        pxa255-idp_defconfig  u8500_defconfig
  dram_0x00000000.config    magician_defconfig       pxa3xx_defconfig      versatile_defconfig
  dram_0xc0000000.config    mainstone_defconfig      pxa910_defconfig      vexpress_defconfig
  dram_0xd0000000.config    milbeaut_m10v_defconfig  pxa_defconfig         vf610m4_defconfig
  ep93xx_defconfig          mini2440_defconfig       qcom_defconfig        viper_defconfig
  eseries_pxa_defconfig     mmp2_defconfig           realview_defconfig    vt8500_v6_v7_defconfig
  exynos_defconfig          moxart_defconfig         rpc_defconfig         xcep_defconfig
  ezx_defconfig             mps2_defconfig           s3c2410_defconfig     zeus_defconfig
  footbridge_defconfig      multi_v4t_defconfig      s3c6400_defconfig

But this doesn't seem to be working reliably on i386:

  kepler:~/tip> make i386_defconfig
  #
  # configuration written to .config
  #
  kepler:~/tip> /bin/cp .config .config.i386_defconfig.1

  kepler:~/tip> make ARCH=i386 defconfig
  *** Default configuration is based on 'i386_defconfig'
  #
  # configuration written to .config
  #
  kepler:~/tip> /bin/cp .config .config.i386_defconfig.2

  kepler:~/tip> diff -up .config.i386_defconfig.1 .config.i386_defconfig.2
  --- .config.i386_defconfig.1	2022-09-04 11:34:48.253202205 +0200
  +++ .config.i386_defconfig.2	2022-09-04 11:35:04.268758331 +0200
  @@ -1,6 +1,6 @@
   #
   # Automatically generated file; DO NOT EDIT.
  -# Linux/x86 6.0.0-rc3 Kernel Configuration
  +# Linux/i386 6.0.0-rc3 Kernel Configuration
   #
   CONFIG_CC_VERSION_TEXT="gcc (Ubuntu 12-20220319-1ubuntu1) 12.0.1 20220319 (experimental) [master r12-7719-g8ca61ad148f]"
   CONFIG_CC_IS_GCC=y
  @@ -261,7 +261,6 @@ CONFIG_PROFILING=y
   CONFIG_TRACEPOINTS=y
   # end of General setup
   
  -# CONFIG_64BIT is not set
   CONFIG_X86_32=y
   CONFIG_X86=y
   CONFIG_INSTRUCTION_DECODER=y

Note how in the ARCH=i386 case the build system claims to use i386_defconfig:

  *** Default configuration is based on 'i386_defconfig'

But that doesn't seem to be identical with when we specify i386_defconfig 
directly as a target...

What am I missing?

Thanks,

	Ingo

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] x86/config: Make the x86 defconfigs a bit more usable
  2022-09-04  9:48                       ` Ingo Molnar
@ 2022-09-05  2:16                         ` Masahiro Yamada
  2022-09-05  9:54                           ` Ingo Molnar
  0 siblings, 1 reply; 6+ messages in thread
From: Masahiro Yamada @ 2022-09-05  2:16 UTC (permalink / raw)
  To: Ingo Molnar
  Cc: Nathan Chancellor, Linux Kbuild mailing list, Linus Torvalds,
	Borislav Petkov, Linux Kernel Mailing List, Peter Zijlstra,
	Will Deacon, Waiman Long, Boqun Feng, Thomas Gleixner,
	Andrew Morton, Sebastian Andrzej Siewior

On Sun, Sep 4, 2022 at 6:48 PM Ingo Molnar <mingo@kernel.org> wrote:
>
>
> * Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> > > Unfortunately, even without the ARCH=i386 'make savedefconfig' doesn't
> > > seem to be doing the right thing & is dropping the '# CONFIG_64BIT is
> > > not set' line:
> >
> >
> > Oh, really?
> >
> > Without ARCH=i386, it works correctly for me.
> >
> >
> >
> > masahiro@zoe:~/ref/linux$ make i386_defconfig savedefconfig
> > #
> > # No change to .config
> > #
> > masahiro@zoe:~/ref/linux$ grep CONFIG_64BIT defconfig
> > # CONFIG_64BIT is not set
>
> Yeah, so why do these two seemingly identical commands produce two
> different .config's:
>
>   $ make ARCH=i386 defconfig
>   *** Default configuration is based on 'i386_defconfig'
>
>   $ make i386_defconfig
>
> ?





As Nathan explained in this thread,
the prompt of CONFIG_64BIT is hidden
when ARCH=i386.


config 64BIT
        bool "64-bit kernel" if "$(ARCH)" = "x86"
        default "$(ARCH)" != "i386"
        help
          Say yes to build a 64-bit kernel - formerly known as x86_64
          Say no to build a 32-bit kernel - formerly known as i386




[1] "make ARCH=i386 defconfig"

ARCH is i386, so the Kconfig snippet becomes as follows:


  config 64BIT
          bool
          default n




[2] "make i386_defconfig"


ARCH is x86, so the Kconfig snippet becomes as follows:


  config 64BIT
          bool "64-bit kernel"
          default y







"# ... is not set" is output when
the prompt is visible and the user did not enable it.












> Basically the canonical way to generate a defconfig is to provide an ARCH,
> then use the common 'defconfig' target:



I do not know what you mean by "canonical", but
there are only 3 architectures (x86, sparc, sh) that
allow two ways for configuration.

This is somewhat related to a historical reason
(commit 8c4d9b145ba3 mentioned this a little).

After arch/i386/ and arch/x86_64/ were merged into arch/x86,
ARCH=i386 and ARCH=x86_64 became a subset of ARCH=x86.






>
>    make ARCH=i386      defconfig
>    make ARCH=x86       defconfig
>    make ARCH=arm       defconfig
>    make ARCH=arm64     defconfig
>    make ARCH=powerpc   defconfig
>    make ARCH=s390      defconfig
>    make ARCH=sparc     defconfig
>    make ARCH=sparc64   defconfig
>    ...
>
> This is what my build test scripts are using to quick-test cross-arch
> builds. It's a straightforward way to generate defconfigs without knowing
> the details of the myriads of random defconfig targets some architectures
> have, such as:
>
>   kepler:~/tip> ls arch/arm/configs/
>   am200epdkit_defconfig     gemini_defconfig         multi_v5_defconfig    s5pv210_defconfig
>   aspeed_g4_defconfig       h3600_defconfig          multi_v7_defconfig    sama5_defconfig
>   aspeed_g5_defconfig       h5000_defconfig          mv78xx0_defconfig     sama7_defconfig
>   assabet_defconfig         hackkit_defconfig        mvebu_v5_defconfig    shannon_defconfig
>   at91_dt_defconfig         hisi_defconfig           mvebu_v7_defconfig    shmobile_defconfig
>   axm55xx_defconfig         imxrt_defconfig          mxs_defconfig         simpad_defconfig
>   badge4_defconfig          imx_v4_v5_defconfig      neponset_defconfig    socfpga_defconfig
>   bcm2835_defconfig         imx_v6_v7_defconfig      netwinder_defconfig   sp7021_defconfig
>   cerfcube_defconfig        integrator_defconfig     nhk8815_defconfig     spear13xx_defconfig
>   clps711x_defconfig        iop32x_defconfig         omap1_defconfig       spear3xx_defconfig
>   cm_x300_defconfig         ixp4xx_defconfig         omap2plus_defconfig   spear6xx_defconfig
>   cns3420vb_defconfig       jornada720_defconfig     orion5x_defconfig     spitz_defconfig
>   colibri_pxa270_defconfig  keystone_defconfig       oxnas_v6_defconfig    stm32_defconfig
>   colibri_pxa300_defconfig  lart_defconfig           palmz72_defconfig     sunxi_defconfig
>   collie_defconfig          lpc18xx_defconfig        pcm027_defconfig      tct_hammer_defconfig
>   corgi_defconfig           lpc32xx_defconfig        pleb_defconfig        tegra_defconfig
>   davinci_all_defconfig     lpd270_defconfig         pxa168_defconfig      trizeps4_defconfig
>   dove_defconfig            lubbock_defconfig        pxa255-idp_defconfig  u8500_defconfig
>   dram_0x00000000.config    magician_defconfig       pxa3xx_defconfig      versatile_defconfig
>   dram_0xc0000000.config    mainstone_defconfig      pxa910_defconfig      vexpress_defconfig
>   dram_0xd0000000.config    milbeaut_m10v_defconfig  pxa_defconfig         vf610m4_defconfig
>   ep93xx_defconfig          mini2440_defconfig       qcom_defconfig        viper_defconfig
>   eseries_pxa_defconfig     mmp2_defconfig           realview_defconfig    vt8500_v6_v7_defconfig
>   exynos_defconfig          moxart_defconfig         rpc_defconfig         xcep_defconfig
>   ezx_defconfig             mps2_defconfig           s3c2410_defconfig     zeus_defconfig
>   footbridge_defconfig      multi_v4t_defconfig      s3c6400_defconfig
>
> But this doesn't seem to be working reliably on i386:
>
>   kepler:~/tip> make i386_defconfig
>   #
>   # configuration written to .config
>   #
>   kepler:~/tip> /bin/cp .config .config.i386_defconfig.1
>
>   kepler:~/tip> make ARCH=i386 defconfig
>   *** Default configuration is based on 'i386_defconfig'
>   #
>   # configuration written to .config
>   #
>   kepler:~/tip> /bin/cp .config .config.i386_defconfig.2
>
>   kepler:~/tip> diff -up .config.i386_defconfig.1 .config.i386_defconfig.2
>   --- .config.i386_defconfig.1  2022-09-04 11:34:48.253202205 +0200
>   +++ .config.i386_defconfig.2  2022-09-04 11:35:04.268758331 +0200
>   @@ -1,6 +1,6 @@
>    #
>    # Automatically generated file; DO NOT EDIT.
>   -# Linux/x86 6.0.0-rc3 Kernel Configuration
>   +# Linux/i386 6.0.0-rc3 Kernel Configuration
>    #
>    CONFIG_CC_VERSION_TEXT="gcc (Ubuntu 12-20220319-1ubuntu1) 12.0.1 20220319 (experimental) [master r12-7719-g8ca61ad148f]"
>    CONFIG_CC_IS_GCC=y
>   @@ -261,7 +261,6 @@ CONFIG_PROFILING=y
>    CONFIG_TRACEPOINTS=y
>    # end of General setup
>
>   -# CONFIG_64BIT is not set
>    CONFIG_X86_32=y
>    CONFIG_X86=y
>    CONFIG_INSTRUCTION_DECODER=y
>
> Note how in the ARCH=i386 case the build system claims to use i386_defconfig:
>
>   *** Default configuration is based on 'i386_defconfig'
>
> But that doesn't seem to be identical with when we specify i386_defconfig
> directly as a target...
>
> What am I missing?
>
> Thanks,
>
>         Ingo





-- 
Best Regards
Masahiro Yamada

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] x86/config: Make the x86 defconfigs a bit more usable
  2022-09-05  2:16                         ` Masahiro Yamada
@ 2022-09-05  9:54                           ` Ingo Molnar
       [not found]                             ` <CAK7LNAQyiNpbLuVjjQ8-GOQECtfQZqsNS8xH0E2ZkLAHYtXt7A@mail.gmail.com>
  0 siblings, 1 reply; 6+ messages in thread
From: Ingo Molnar @ 2022-09-05  9:54 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: Nathan Chancellor, Linux Kbuild mailing list, Linus Torvalds,
	Borislav Petkov, Linux Kernel Mailing List, Peter Zijlstra,
	Will Deacon, Waiman Long, Boqun Feng, Thomas Gleixner,
	Andrew Morton, Sebastian Andrzej Siewior


* Masahiro Yamada <masahiroy@kernel.org> wrote:

> On Sun, Sep 4, 2022 at 6:48 PM Ingo Molnar <mingo@kernel.org> wrote:
> >
> >
> > * Masahiro Yamada <masahiroy@kernel.org> wrote:
> >
> > > > Unfortunately, even without the ARCH=i386 'make savedefconfig' doesn't
> > > > seem to be doing the right thing & is dropping the '# CONFIG_64BIT is
> > > > not set' line:
> > >
> > >
> > > Oh, really?
> > >
> > > Without ARCH=i386, it works correctly for me.
> > >
> > >
> > >
> > > masahiro@zoe:~/ref/linux$ make i386_defconfig savedefconfig
> > > #
> > > # No change to .config
> > > #
> > > masahiro@zoe:~/ref/linux$ grep CONFIG_64BIT defconfig
> > > # CONFIG_64BIT is not set
> >
> > Yeah, so why do these two seemingly identical commands produce two
> > different .config's:
> >
> >   $ make ARCH=i386 defconfig
> >   *** Default configuration is based on 'i386_defconfig'
> >
> >   $ make i386_defconfig
> >
> > ?
> 
> 
> 
> As Nathan explained in this thread,
> the prompt of CONFIG_64BIT is hidden
> when ARCH=i386.

Yeah, so my 'why' question was more about why we'd tolerate the UI 
inconsistency in seemingly similar commands generating subtly different 
.config's.

In other words, what should we modify in this Kconfig block, or in other 
parts of the kernel:

> config 64BIT
>         bool "64-bit kernel" if "$(ARCH)" = "x86"
>         default "$(ARCH)" != "i386"
>         help
>           Say yes to build a 64-bit kernel - formerly known as x86_64
>           Say no to build a 32-bit kernel - formerly known as i386

... to not have this Kconfig UI quirk/bug/inconsistency?

I hope we agree that the status quo is not ideal.

Thanks,

	Ingo

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] x86/config: Make the x86 defconfigs a bit more usable
       [not found]                             ` <CAK7LNAQyiNpbLuVjjQ8-GOQECtfQZqsNS8xH0E2ZkLAHYtXt7A@mail.gmail.com>
@ 2022-09-10 17:28                               ` Linus Torvalds
  0 siblings, 0 replies; 6+ messages in thread
From: Linus Torvalds @ 2022-09-10 17:28 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: Ingo Molnar, Nathan Chancellor, Linux Kbuild mailing list,
	Borislav Petkov, Linux Kernel Mailing List, Peter Zijlstra,
	Will Deacon, Waiman Long, Boqun Feng, Thomas Gleixner,
	Andrew Morton, Sebastian Andrzej Siewior

On Fri, Sep 9, 2022 at 6:05 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> If you do not like the inconsistency,
> the support for ARCH=i386 and ARCH=x86_64 must be removed.

Is there any sane alternative for "do cross-architecture test builds"?

I do things like "make ARCH=i386 allmodconfig" myself, and I have to
admit that it's annoying that you have to then remember to do "make
ARCH=ii386" to do the actual build too, because otherwise Kcoinfig
will mess up the architecture, because it didn't make it into the
final simplified .config.

This is probably more noticeable with "defconfig" because then the
"ARCH=xyz" part has *other* effects too (ie it is also what says
*which* defconfig to pick).

So this is a bit of an annoyance, in that it's not trivial to just
"make the config for ARCH xyz" and then "make".

                       Linus

^ permalink raw reply	[flat|nested] 6+ messages in thread

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2022-09-02  8:50                   ` [PATCH] x86/config: Make the x86 defconfigs a bit more usable Ingo Molnar
2022-09-02  9:18                     ` Masahiro Yamada
2022-09-04  9:48                       ` Ingo Molnar
2022-09-05  2:16                         ` Masahiro Yamada
2022-09-05  9:54                           ` Ingo Molnar
     [not found]                             ` <CAK7LNAQyiNpbLuVjjQ8-GOQECtfQZqsNS8xH0E2ZkLAHYtXt7A@mail.gmail.com>
2022-09-10 17:28                               ` Linus Torvalds

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