[PATCH] x86: select ARCH_WANT_FRAME_POINTERS again when UNWINDER_FRAME_POINTER=y

[PATCH] x86: select ARCH_WANT_FRAME_POINTERS again when UNWINDER_FRAME_POINTER=y

[Masahiro Yamada]

It took me some time to understand the purpose of the tricky code at
the end of arch/x86/Kconfig.debug.

Without it, the following would be shown:

  WARNING: unmet direct dependencies detected for FRAME_POINTER

because commit 81d387190039 ("x86/kconfig: Consolidate unwinders into
multiple choice selection") removed 'select ARCH_WANT_FRAME_POINTERS'.

The correct and more straightforward approach should have been to move
it where 'select FRAME_POINTER' is located.

Several architectures properly handle the conditional selection of
ARCH_WANT_FRAME_POINTERS. For example, 'config UNWINDER_FRAME_POINTER'
in arch/arm/Kconfig.debug.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 arch/x86/Kconfig.debug | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index c5d614d28a75..74777a97e394 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -248,6 +248,7 @@ config UNWINDER_ORC
 
 config UNWINDER_FRAME_POINTER
 	bool "Frame pointer unwinder"
+	select ARCH_WANT_FRAME_POINTERS
 	select FRAME_POINTER
 	help
 	  This option enables the frame pointer unwinder for unwinding kernel
@@ -271,7 +272,3 @@ config UNWINDER_GUESS
 	  overhead.
 
 endchoice
-
-config FRAME_POINTER
-	depends on !UNWINDER_ORC && !UNWINDER_GUESS
-	bool
-- 
2.40.1

Re: [PATCH] x86: select ARCH_WANT_FRAME_POINTERS again when UNWINDER_FRAME_POINTER=y

[Masahiro Yamada]

Ping?


On Sun, Feb 4, 2024 at 9:20 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> It took me some time to understand the purpose of the tricky code at
> the end of arch/x86/Kconfig.debug.
>
> Without it, the following would be shown:
>
>   WARNING: unmet direct dependencies detected for FRAME_POINTER
>
> because commit 81d387190039 ("x86/kconfig: Consolidate unwinders into
> multiple choice selection") removed 'select ARCH_WANT_FRAME_POINTERS'.
>
> The correct and more straightforward approach should have been to move
> it where 'select FRAME_POINTER' is located.
>
> Several architectures properly handle the conditional selection of
> ARCH_WANT_FRAME_POINTERS. For example, 'config UNWINDER_FRAME_POINTER'
> in arch/arm/Kconfig.debug.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
>
>  arch/x86/Kconfig.debug | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
> index c5d614d28a75..74777a97e394 100644
> --- a/arch/x86/Kconfig.debug
> +++ b/arch/x86/Kconfig.debug
> @@ -248,6 +248,7 @@ config UNWINDER_ORC
>
>  config UNWINDER_FRAME_POINTER
>         bool "Frame pointer unwinder"
> +       select ARCH_WANT_FRAME_POINTERS
>         select FRAME_POINTER
>         help
>           This option enables the frame pointer unwinder for unwinding kernel
> @@ -271,7 +272,3 @@ config UNWINDER_GUESS
>           overhead.
>
>  endchoice
> -
> -config FRAME_POINTER
> -       depends on !UNWINDER_ORC && !UNWINDER_GUESS
> -       bool
> --
> 2.40.1
>


-- 
Best Regards
Masahiro Yamada

Re: [PATCH] x86: select ARCH_WANT_FRAME_POINTERS again when UNWINDER_FRAME_POINTER=y

[Masahiro Yamada]

Hi, x86 maintainers


Please check this.


And, please also note the current code is incorrect,
and it may get broken with future Kconfig refactoring.





On Thu, Mar 21, 2024 at 12:30 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> Ping?
>
>
> On Sun, Feb 4, 2024 at 9:20 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
> >
> > It took me some time to understand the purpose of the tricky code at
> > the end of arch/x86/Kconfig.debug.
> >
> > Without it, the following would be shown:
> >
> >   WARNING: unmet direct dependencies detected for FRAME_POINTER
> >
> > because commit 81d387190039 ("x86/kconfig: Consolidate unwinders into
> > multiple choice selection") removed 'select ARCH_WANT_FRAME_POINTERS'.
> >
> > The correct and more straightforward approach should have been to move
> > it where 'select FRAME_POINTER' is located.
> >
> > Several architectures properly handle the conditional selection of
> > ARCH_WANT_FRAME_POINTERS. For example, 'config UNWINDER_FRAME_POINTER'
> > in arch/arm/Kconfig.debug.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> > ---
> >
> >  arch/x86/Kconfig.debug | 5 +----
> >  1 file changed, 1 insertion(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
> > index c5d614d28a75..74777a97e394 100644
> > --- a/arch/x86/Kconfig.debug
> > +++ b/arch/x86/Kconfig.debug
> > @@ -248,6 +248,7 @@ config UNWINDER_ORC
> >
> >  config UNWINDER_FRAME_POINTER
> >         bool "Frame pointer unwinder"
> > +       select ARCH_WANT_FRAME_POINTERS
> >         select FRAME_POINTER
> >         help
> >           This option enables the frame pointer unwinder for unwinding kernel
> > @@ -271,7 +272,3 @@ config UNWINDER_GUESS
> >           overhead.
> >
> >  endchoice
> > -
> > -config FRAME_POINTER
> > -       depends on !UNWINDER_ORC && !UNWINDER_GUESS
> > -       bool
> > --
> > 2.40.1
> >
>
>
> --
> Best Regards
> Masahiro Yamada



--
Best Regards
Masahiro Yamada

Re: [PATCH] x86: select ARCH_WANT_FRAME_POINTERS again when UNWINDER_FRAME_POINTER=y

[Josh Poimboeuf]

On Sun, Feb 04, 2024 at 09:20:03PM +0900, Masahiro Yamada wrote:
> It took me some time to understand the purpose of the tricky code at
> the end of arch/x86/Kconfig.debug.
> 
> Without it, the following would be shown:
> 
>   WARNING: unmet direct dependencies detected for FRAME_POINTER
> 
> because commit 81d387190039 ("x86/kconfig: Consolidate unwinders into
> multiple choice selection") removed 'select ARCH_WANT_FRAME_POINTERS'.
> 
> The correct and more straightforward approach should have been to move
> it where 'select FRAME_POINTER' is located.
> 
> Several architectures properly handle the conditional selection of
> ARCH_WANT_FRAME_POINTERS. For example, 'config UNWINDER_FRAME_POINTER'
> in arch/arm/Kconfig.debug.
> 
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Looks good, thanks for fixing that!

Fixes: 81d387190039 ("x86/kconfig: Consolidate unwinders into multiple choice selection")
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>

-- 
Josh

[tip: x86/urgent] x86/kconfig: Select ARCH_WANT_FRAME_POINTERS again when UNWINDER_FRAME_POINTER=y

[tip-bot2 for Masahiro Yamada]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     66ee3636eddcc82ab82b539d08b85fb5ac1dff9b
Gitweb:        https://git.kernel.org/tip/66ee3636eddcc82ab82b539d08b85fb5ac1dff9b
Author:        Masahiro Yamada <masahiroy@kernel.org>
AuthorDate:    Sun, 04 Feb 2024 21:20:03 +09:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Mon, 20 May 2024 11:37:23 +02:00

x86/kconfig: Select ARCH_WANT_FRAME_POINTERS again when UNWINDER_FRAME_POINTER=y

It took me some time to understand the purpose of the tricky code at
the end of arch/x86/Kconfig.debug.

Without it, the following would be shown:

  WARNING: unmet direct dependencies detected for FRAME_POINTER

because

  81d387190039 ("x86/kconfig: Consolidate unwinders into multiple choice selection")

removed 'select ARCH_WANT_FRAME_POINTERS'.

The correct and more straightforward approach should have been to move
it where 'select FRAME_POINTER' is located.

Several architectures properly handle the conditional selection of
ARCH_WANT_FRAME_POINTERS. For example, 'config UNWINDER_FRAME_POINTER'
in arch/arm/Kconfig.debug.

Fixes: 81d387190039 ("x86/kconfig: Consolidate unwinders into multiple choice selection")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20240204122003.53795-1-masahiroy@kernel.org
---
 arch/x86/Kconfig.debug | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index c5d614d..74777a9 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -248,6 +248,7 @@ config UNWINDER_ORC
 
 config UNWINDER_FRAME_POINTER
 	bool "Frame pointer unwinder"
+	select ARCH_WANT_FRAME_POINTERS
 	select FRAME_POINTER
 	help
 	  This option enables the frame pointer unwinder for unwinding kernel
@@ -271,7 +272,3 @@ config UNWINDER_GUESS
 	  overhead.
 
 endchoice
-
-config FRAME_POINTER
-	depends on !UNWINDER_ORC && !UNWINDER_GUESS
-	bool