diff mbox series

[7/7,v4] sh: mcount.S: fix build error when PRINTK is not enabled

Message ID	20230306040037.20350-8-rdunlap@infradead.org
State	New
Headers	Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; From: Randy Dunlap <rdunlap@infradead.org> To: linux-kernel@vger.kernel.org Cc: Randy Dunlap <rdunlap@infradead.org>, John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>, Yoshinori Sato <ysato@users.sourceforge.jp>, Rich Felker <dalias@libc.org>, Geert Uytterhoeven <geert@linux-m68k.org>, stable@vger.kernel.org Subject: [PATCH 7/7 v4] sh: mcount.S: fix build error when PRINTK is not enabled Date: Sun, 5 Mar 2023 20:00:37 -0800 Message-Id: <20230306040037.20350-8-rdunlap@infradead.org> In-Reply-To: <20230306040037.20350-1-rdunlap@infradead.org> References: <20230306040037.20350-1-rdunlap@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	sh: various doc, build, init fixes \| [0/7,v4] sh: various doc, build, init fixes [1/7,v4] sh: SH2007: drop the bad URL info [2/7,v4] sh: nmi_debug: fix return value of __setup handler [3/7,v4] sh: init: use OF_EARLY_FLATTREE for early init [4/7,v4] sh: math-emu: fix macro redefined warning [5/7,v4] sh: remove sh5/sh64 last fragments [6/7,v4] sh: fix Kconfig entry for NUMA => SMP [7/7,v4] sh: mcount.S: fix build error when PRINTK is not enabled

Commit Message

Randy Dunlap March 6, 2023, 4 a.m. UTC

  Fix a build error in mcount.S when CONFIG_PRINTK is not enabled.
Fixes this build error:

sh2-linux-ld: arch/sh/lib/mcount.o: in function `stack_panic':
(.text+0xec): undefined reference to `dump_stack'

Fixes: e460ab27b6c3 ("sh: Fix up stack overflow check with ftrace disabled.")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org
---
v2: add PRINTK to STACK_DEBUG dependency (thanks, Geert)
v3: skipped
v4: refresh & resend

 arch/sh/Kconfig.debug |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

John Paul Adrian Glaubitz March 19, 2023, 8:49 p.m. UTC | #1

On Sun, 2023-03-05 at 20:00 -0800, Randy Dunlap wrote:
> Fix a build error in mcount.S when CONFIG_PRINTK is not enabled.
> Fixes this build error:
> 
> sh2-linux-ld: arch/sh/lib/mcount.o: in function `stack_panic':
> (.text+0xec): undefined reference to `dump_stack'
> 
> Fixes: e460ab27b6c3 ("sh: Fix up stack overflow check with ftrace disabled.")
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: Rich Felker <dalias@libc.org>
> Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: stable@vger.kernel.org
> ---
> v2: add PRINTK to STACK_DEBUG dependency (thanks, Geert)
> v3: skipped
> v4: refresh & resend
> 
>  arch/sh/Kconfig.debug |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff -- a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
> --- a/arch/sh/Kconfig.debug
> +++ b/arch/sh/Kconfig.debug
> @@ -15,7 +15,7 @@ config SH_STANDARD_BIOS
>  
>  config STACK_DEBUG
>  	bool "Check for stack overflows"
> -	depends on DEBUG_KERNEL
> +	depends on DEBUG_KERNEL && PRINTK
>  	help
>  	  This option will cause messages to be printed if free stack space
>  	  drops below a certain limit. Saying Y here will add overhead to

I can't really test this change as the moment I am enabling CONFIG_STACK_DEBUG,
the build fails with:

  CC      scripts/mod/devicetable-offsets.s
sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
make[1]: *** [scripts/Makefile.build:252: scripts/mod/empty.o] Error 1
make[1]: *** Waiting for unfinished jobs....
sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
make[1]: *** [scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 1
make: *** [Makefile:1286: prepare0] Error 2

So, I assume we need to strip -fomit-frame-pointer from KBUILD_CFLAGS, correct?

I tried this change, but that doesn't fix it for me:

diff --git a/arch/sh/Makefile b/arch/sh/Makefile
index 5c8776482530..83f535b73835 100644
--- a/arch/sh/Makefile
+++ b/arch/sh/Makefile
@@ -173,6 +173,7 @@ KBUILD_AFLAGS               += $(cflags-y)
 
 ifeq ($(CONFIG_MCOUNT),y)
   KBUILD_CFLAGS += -pg
+  KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS))
 endif
 
 ifeq ($(CONFIG_DWARF_UNWINDER),y)

Any ideas?

Adrian

Geert Uytterhoeven March 20, 2023, 8:16 a.m. UTC | #2

Hi Adrian,

On Sun, Mar 19, 2023 at 9:49 PM John Paul Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> wrote:
> On Sun, 2023-03-05 at 20:00 -0800, Randy Dunlap wrote:
> > Fix a build error in mcount.S when CONFIG_PRINTK is not enabled.
> > Fixes this build error:
> >
> > sh2-linux-ld: arch/sh/lib/mcount.o: in function `stack_panic':
> > (.text+0xec): undefined reference to `dump_stack'
> >
> > Fixes: e460ab27b6c3 ("sh: Fix up stack overflow check with ftrace disabled.")
> > Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> > Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> > Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> > Cc: Rich Felker <dalias@libc.org>
> > Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > Cc: stable@vger.kernel.org
> > ---
> > v2: add PRINTK to STACK_DEBUG dependency (thanks, Geert)
> > v3: skipped
> > v4: refresh & resend
> >
> >  arch/sh/Kconfig.debug |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff -- a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
> > --- a/arch/sh/Kconfig.debug
> > +++ b/arch/sh/Kconfig.debug
> > @@ -15,7 +15,7 @@ config SH_STANDARD_BIOS
> >
> >  config STACK_DEBUG
> >       bool "Check for stack overflows"
> > -     depends on DEBUG_KERNEL
> > +     depends on DEBUG_KERNEL && PRINTK
> >       help
> >         This option will cause messages to be printed if free stack space
> >         drops below a certain limit. Saying Y here will add overhead to
>
> I can't really test this change as the moment I am enabling CONFIG_STACK_DEBUG,
> the build fails with:
>
>   CC      scripts/mod/devicetable-offsets.s
> sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> make[1]: *** [scripts/Makefile.build:252: scripts/mod/empty.o] Error 1
> make[1]: *** Waiting for unfinished jobs....
> sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> make[1]: *** [scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 1
> make: *** [Makefile:1286: prepare0] Error 2
>
> So, I assume we need to strip -fomit-frame-pointer from KBUILD_CFLAGS, correct?
>
> I tried this change, but that doesn't fix it for me:
>
> diff --git a/arch/sh/Makefile b/arch/sh/Makefile
> index 5c8776482530..83f535b73835 100644
> --- a/arch/sh/Makefile
> +++ b/arch/sh/Makefile
> @@ -173,6 +173,7 @@ KBUILD_AFLAGS               += $(cflags-y)
>
>  ifeq ($(CONFIG_MCOUNT),y)
>    KBUILD_CFLAGS += -pg
> +  KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS))
>  endif
>
>  ifeq ($(CONFIG_DWARF_UNWINDER),y)
>
> Any ideas?

Please try with "+=" instead of ":=".

Gr{oetje,eeting}s,

                        Geert

John Paul Adrian Glaubitz March 20, 2023, 9:13 a.m. UTC | #3

Hi Geert!

On Mon, 2023-03-20 at 09:16 +0100, Geert Uytterhoeven wrote:
> Hi Adrian,
> 
> On Sun, Mar 19, 2023 at 9:49 PM John Paul Adrian Glaubitz
> <glaubitz@physik.fu-berlin.de> wrote:
> > On Sun, 2023-03-05 at 20:00 -0800, Randy Dunlap wrote:
> > > Fix a build error in mcount.S when CONFIG_PRINTK is not enabled.
> > > Fixes this build error:
> > > 
> > > sh2-linux-ld: arch/sh/lib/mcount.o: in function `stack_panic':
> > > (.text+0xec): undefined reference to `dump_stack'
> > > 
> > > Fixes: e460ab27b6c3 ("sh: Fix up stack overflow check with ftrace disabled.")
> > > Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> > > Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> > > Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> > > Cc: Rich Felker <dalias@libc.org>
> > > Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > > Cc: stable@vger.kernel.org
> > > ---
> > > v2: add PRINTK to STACK_DEBUG dependency (thanks, Geert)
> > > v3: skipped
> > > v4: refresh & resend
> > > 
> > >  arch/sh/Kconfig.debug |    2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff -- a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
> > > --- a/arch/sh/Kconfig.debug
> > > +++ b/arch/sh/Kconfig.debug
> > > @@ -15,7 +15,7 @@ config SH_STANDARD_BIOS
> > > 
> > >  config STACK_DEBUG
> > >       bool "Check for stack overflows"
> > > -     depends on DEBUG_KERNEL
> > > +     depends on DEBUG_KERNEL && PRINTK
> > >       help
> > >         This option will cause messages to be printed if free stack space
> > >         drops below a certain limit. Saying Y here will add overhead to
> > 
> > I can't really test this change as the moment I am enabling CONFIG_STACK_DEBUG,
> > the build fails with:
> > 
> >   CC      scripts/mod/devicetable-offsets.s
> > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> > make[1]: *** [scripts/Makefile.build:252: scripts/mod/empty.o] Error 1
> > make[1]: *** Waiting for unfinished jobs....
> > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> > make[1]: *** [scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 1
> > make: *** [Makefile:1286: prepare0] Error 2
> > 
> > So, I assume we need to strip -fomit-frame-pointer from KBUILD_CFLAGS, correct?
> > 
> > I tried this change, but that doesn't fix it for me:
> > 
> > diff --git a/arch/sh/Makefile b/arch/sh/Makefile
> > index 5c8776482530..83f535b73835 100644
> > --- a/arch/sh/Makefile
> > +++ b/arch/sh/Makefile
> > @@ -173,6 +173,7 @@ KBUILD_AFLAGS               += $(cflags-y)
> > 
> >  ifeq ($(CONFIG_MCOUNT),y)
> >    KBUILD_CFLAGS += -pg
> > +  KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS))
> >  endif
> > 
> >  ifeq ($(CONFIG_DWARF_UNWINDER),y)
> > 
> > Any ideas?
> 
> Please try with "+=" instead of ":=".

That doesn't work either. I tried the following, but that didn't strip -fomit-frame-pointer:

diff --git a/arch/sh/Makefile b/arch/sh/Makefile
index 5c8776482530..9eef6f6ffc8b 100644
--- a/arch/sh/Makefile
+++ b/arch/sh/Makefile
@@ -172,7 +172,7 @@ KBUILD_CPPFLAGS             += $(cflags-y)
 KBUILD_AFLAGS          += $(cflags-y)
 
 ifeq ($(CONFIG_MCOUNT),y)
-  KBUILD_CFLAGS += -pg
+  KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS)) -pg
 endif
 
 ifeq ($(CONFIG_DWARF_UNWINDER),y)

I will have to do some more digging tonight.

Adrian

Geert Uytterhoeven March 20, 2023, 12:42 p.m. UTC | #4

Hi Adrian,

On Mon, Mar 20, 2023 at 10:13 AM John Paul Adrian Glaubitz
<glaubitz@physik.fu-berlin.de> wrote:
> On Mon, 2023-03-20 at 09:16 +0100, Geert Uytterhoeven wrote:
> > On Sun, Mar 19, 2023 at 9:49 PM John Paul Adrian Glaubitz
> > <glaubitz@physik.fu-berlin.de> wrote:
> > > On Sun, 2023-03-05 at 20:00 -0800, Randy Dunlap wrote:
> > > > Fix a build error in mcount.S when CONFIG_PRINTK is not enabled.
> > > > Fixes this build error:
> > > >
> > > > sh2-linux-ld: arch/sh/lib/mcount.o: in function `stack_panic':
> > > > (.text+0xec): undefined reference to `dump_stack'
> > > >
> > > > Fixes: e460ab27b6c3 ("sh: Fix up stack overflow check with ftrace disabled.")
> > > > Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> > > > Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> > > > Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> > > > Cc: Rich Felker <dalias@libc.org>
> > > > Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > > > Cc: stable@vger.kernel.org
> > > > ---
> > > > v2: add PRINTK to STACK_DEBUG dependency (thanks, Geert)
> > > > v3: skipped
> > > > v4: refresh & resend
> > > >
> > > >  arch/sh/Kconfig.debug |    2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff -- a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
> > > > --- a/arch/sh/Kconfig.debug
> > > > +++ b/arch/sh/Kconfig.debug
> > > > @@ -15,7 +15,7 @@ config SH_STANDARD_BIOS
> > > >
> > > >  config STACK_DEBUG
> > > >       bool "Check for stack overflows"
> > > > -     depends on DEBUG_KERNEL
> > > > +     depends on DEBUG_KERNEL && PRINTK
> > > >       help
> > > >         This option will cause messages to be printed if free stack space
> > > >         drops below a certain limit. Saying Y here will add overhead to
> > >
> > > I can't really test this change as the moment I am enabling CONFIG_STACK_DEBUG,
> > > the build fails with:
> > >
> > >   CC      scripts/mod/devicetable-offsets.s
> > > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> > > make[1]: *** [scripts/Makefile.build:252: scripts/mod/empty.o] Error 1
> > > make[1]: *** Waiting for unfinished jobs....
> > > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> > > make[1]: *** [scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 1
> > > make: *** [Makefile:1286: prepare0] Error 2
> > >
> > > So, I assume we need to strip -fomit-frame-pointer from KBUILD_CFLAGS, correct?
> > >
> > > I tried this change, but that doesn't fix it for me:
> > >
> > > diff --git a/arch/sh/Makefile b/arch/sh/Makefile
> > > index 5c8776482530..83f535b73835 100644
> > > --- a/arch/sh/Makefile
> > > +++ b/arch/sh/Makefile
> > > @@ -173,6 +173,7 @@ KBUILD_AFLAGS               += $(cflags-y)
> > >
> > >  ifeq ($(CONFIG_MCOUNT),y)
> > >    KBUILD_CFLAGS += -pg
> > > +  KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS))
> > >  endif
> > >
> > >  ifeq ($(CONFIG_DWARF_UNWINDER),y)
> > >
> > > Any ideas?
> >
> > Please try with "+=" instead of ":=".
>
> That doesn't work either. I tried the following, but that didn't strip -fomit-frame-pointer:

Oops, obviously all of that happened before my morning coffee ;-)

Makefile has:

    ifdef CONFIG_FRAME_POINTER
    KBUILD_CFLAGS   += -fno-omit-frame-pointer -fno-optimize-sibling-calls
    KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y
    else
    # Some targets (ARM with Thumb2, for example), can't be built with frame
    # pointers.  For those, we don't have FUNCTION_TRACER automatically
    # select FRAME_POINTER.  However, FUNCTION_TRACER adds -pg, and this is
    # incompatible with -fomit-frame-pointer with current GCC, so we don't use
    # -fomit-frame-pointer with FUNCTION_TRACER.
    # In the Rust target specification, "frame-pointer" is set explicitly
    # to "may-omit".
    ifndef CONFIG_FUNCTION_TRACER
    KBUILD_CFLAGS   += -fomit-frame-pointer
    endif
    endif

Your config probably has CONFIG_FRAME_POINTER set?

    arch/sh/Kconfig.debug=config DWARF_UNWINDER
    arch/sh/Kconfig.debug-  bool "Enable the DWARF unwinder for stacktraces"
    arch/sh/Kconfig.debug-  depends on DEBUG_KERNEL
    arch/sh/Kconfig.debug:  select FRAME_POINTER

You should make sure that cannot happen when CONFIG_FUNCTION_TRACER
is enabled. I.e. make DWARF_UNWINDER depend on !FUNCTION_TRACER?

Other architectures do something similar:

    arch/sparc/Kconfig.debug:config FRAME_POINTER
    arch/sparc/Kconfig.debug-       bool
    arch/sparc/Kconfig.debug-       depends on MCOUNT

    arch/x86/Kconfig.debug:config FRAME_POINTER
    arch/x86/Kconfig.debug- depends on !UNWINDER_ORC && !UNWINDER_GUESS
    arch/x86/Kconfig.debug- bool

Probably you need to adjust the following, too:

    lib/Kconfig.debug:config FRAME_POINTER
    lib/Kconfig.debug-      bool "Compile the kernel with frame pointers"
    lib/Kconfig.debug-      depends on DEBUG_KERNEL && (M68K || UML ||
SUPERH) || ARCH_WANT_FRAME_POINTERS
    lib/Kconfig.debug-      default y if (DEBUG_INFO && UML) ||
ARCH_WANT_FRAME_POINTERS

i.e. drop SUPERH from the list above, and select ARCH_WANT_FRAME_POINTERS
if !FUNCTION_TRACER.

Gr{oetje,eeting}s,

                        Geert

Geert Uytterhoeven March 20, 2023, 12:43 p.m. UTC | #5

CC linux-sh

On Mon, Mar 20, 2023 at 1:42 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Mon, Mar 20, 2023 at 10:13 AM John Paul Adrian Glaubitz
> <glaubitz@physik.fu-berlin.de> wrote:
> > On Mon, 2023-03-20 at 09:16 +0100, Geert Uytterhoeven wrote:
> > > On Sun, Mar 19, 2023 at 9:49 PM John Paul Adrian Glaubitz
> > > <glaubitz@physik.fu-berlin.de> wrote:
> > > > On Sun, 2023-03-05 at 20:00 -0800, Randy Dunlap wrote:
> > > > > Fix a build error in mcount.S when CONFIG_PRINTK is not enabled.
> > > > > Fixes this build error:
> > > > >
> > > > > sh2-linux-ld: arch/sh/lib/mcount.o: in function `stack_panic':
> > > > > (.text+0xec): undefined reference to `dump_stack'
> > > > >
> > > > > Fixes: e460ab27b6c3 ("sh: Fix up stack overflow check with ftrace disabled.")
> > > > > Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> > > > > Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> > > > > Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> > > > > Cc: Rich Felker <dalias@libc.org>
> > > > > Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > > > > Cc: stable@vger.kernel.org
> > > > > ---
> > > > > v2: add PRINTK to STACK_DEBUG dependency (thanks, Geert)
> > > > > v3: skipped
> > > > > v4: refresh & resend
> > > > >
> > > > >  arch/sh/Kconfig.debug |    2 +-
> > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > >
> > > > > diff -- a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
> > > > > --- a/arch/sh/Kconfig.debug
> > > > > +++ b/arch/sh/Kconfig.debug
> > > > > @@ -15,7 +15,7 @@ config SH_STANDARD_BIOS
> > > > >
> > > > >  config STACK_DEBUG
> > > > >       bool "Check for stack overflows"
> > > > > -     depends on DEBUG_KERNEL
> > > > > +     depends on DEBUG_KERNEL && PRINTK
> > > > >       help
> > > > >         This option will cause messages to be printed if free stack space
> > > > >         drops below a certain limit. Saying Y here will add overhead to
> > > >
> > > > I can't really test this change as the moment I am enabling CONFIG_STACK_DEBUG,
> > > > the build fails with:
> > > >
> > > >   CC      scripts/mod/devicetable-offsets.s
> > > > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> > > > make[1]: *** [scripts/Makefile.build:252: scripts/mod/empty.o] Error 1
> > > > make[1]: *** Waiting for unfinished jobs....
> > > > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> > > > make[1]: *** [scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 1
> > > > make: *** [Makefile:1286: prepare0] Error 2
> > > >
> > > > So, I assume we need to strip -fomit-frame-pointer from KBUILD_CFLAGS, correct?
> > > >
> > > > I tried this change, but that doesn't fix it for me:
> > > >
> > > > diff --git a/arch/sh/Makefile b/arch/sh/Makefile
> > > > index 5c8776482530..83f535b73835 100644
> > > > --- a/arch/sh/Makefile
> > > > +++ b/arch/sh/Makefile
> > > > @@ -173,6 +173,7 @@ KBUILD_AFLAGS               += $(cflags-y)
> > > >
> > > >  ifeq ($(CONFIG_MCOUNT),y)
> > > >    KBUILD_CFLAGS += -pg
> > > > +  KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS))
> > > >  endif
> > > >
> > > >  ifeq ($(CONFIG_DWARF_UNWINDER),y)
> > > >
> > > > Any ideas?
> > >
> > > Please try with "+=" instead of ":=".
> >
> > That doesn't work either. I tried the following, but that didn't strip -fomit-frame-pointer:
>
> Oops, obviously all of that happened before my morning coffee ;-)
>
> Makefile has:
>
>     ifdef CONFIG_FRAME_POINTER
>     KBUILD_CFLAGS   += -fno-omit-frame-pointer -fno-optimize-sibling-calls
>     KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y
>     else
>     # Some targets (ARM with Thumb2, for example), can't be built with frame
>     # pointers.  For those, we don't have FUNCTION_TRACER automatically
>     # select FRAME_POINTER.  However, FUNCTION_TRACER adds -pg, and this is
>     # incompatible with -fomit-frame-pointer with current GCC, so we don't use
>     # -fomit-frame-pointer with FUNCTION_TRACER.
>     # In the Rust target specification, "frame-pointer" is set explicitly
>     # to "may-omit".
>     ifndef CONFIG_FUNCTION_TRACER
>     KBUILD_CFLAGS   += -fomit-frame-pointer
>     endif
>     endif
>
> Your config probably has CONFIG_FRAME_POINTER set?
>
>     arch/sh/Kconfig.debug=config DWARF_UNWINDER
>     arch/sh/Kconfig.debug-  bool "Enable the DWARF unwinder for stacktraces"
>     arch/sh/Kconfig.debug-  depends on DEBUG_KERNEL
>     arch/sh/Kconfig.debug:  select FRAME_POINTER
>
> You should make sure that cannot happen when CONFIG_FUNCTION_TRACER
> is enabled. I.e. make DWARF_UNWINDER depend on !FUNCTION_TRACER?
>
> Other architectures do something similar:
>
>     arch/sparc/Kconfig.debug:config FRAME_POINTER
>     arch/sparc/Kconfig.debug-       bool
>     arch/sparc/Kconfig.debug-       depends on MCOUNT
>
>     arch/x86/Kconfig.debug:config FRAME_POINTER
>     arch/x86/Kconfig.debug- depends on !UNWINDER_ORC && !UNWINDER_GUESS
>     arch/x86/Kconfig.debug- bool
>
> Probably you need to adjust the following, too:
>
>     lib/Kconfig.debug:config FRAME_POINTER
>     lib/Kconfig.debug-      bool "Compile the kernel with frame pointers"
>     lib/Kconfig.debug-      depends on DEBUG_KERNEL && (M68K || UML ||
> SUPERH) || ARCH_WANT_FRAME_POINTERS
>     lib/Kconfig.debug-      default y if (DEBUG_INFO && UML) ||
> ARCH_WANT_FRAME_POINTERS
>
> i.e. drop SUPERH from the list above, and select ARCH_WANT_FRAME_POINTERS
> if !FUNCTION_TRACER.
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds

John Paul Adrian Glaubitz March 20, 2023, 1:32 p.m. UTC | #6

Hi Geert!

On Mon, 2023-03-20 at 13:42 +0100, Geert Uytterhoeven wrote:
> Oops, obviously all of that happened before my morning coffee ;-)
> 
> Makefile has:
> 
>     ifdef CONFIG_FRAME_POINTER
>     KBUILD_CFLAGS   += -fno-omit-frame-pointer -fno-optimize-sibling-calls
>     KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y
>     else
>     # Some targets (ARM with Thumb2, for example), can't be built with frame
>     # pointers.  For those, we don't have FUNCTION_TRACER automatically
>     # select FRAME_POINTER.  However, FUNCTION_TRACER adds -pg, and this is
>     # incompatible with -fomit-frame-pointer with current GCC, so we don't use
>     # -fomit-frame-pointer with FUNCTION_TRACER.
>     # In the Rust target specification, "frame-pointer" is set explicitly
>     # to "may-omit".
>     ifndef CONFIG_FUNCTION_TRACER
>     KBUILD_CFLAGS   += -fomit-frame-pointer
>     endif
>     endif
> 
> Your config probably has CONFIG_FRAME_POINTER set?
> 
>     arch/sh/Kconfig.debug=config DWARF_UNWINDER
>     arch/sh/Kconfig.debug-  bool "Enable the DWARF unwinder for stacktraces"
>     arch/sh/Kconfig.debug-  depends on DEBUG_KERNEL
>     arch/sh/Kconfig.debug:  select FRAME_POINTER
> 
> You should make sure that cannot happen when CONFIG_FUNCTION_TRACER
> is enabled. I.e. make DWARF_UNWINDER depend on !FUNCTION_TRACER?
> 
> Other architectures do something similar:
> 
>     arch/sparc/Kconfig.debug:config FRAME_POINTER
>     arch/sparc/Kconfig.debug-       bool
>     arch/sparc/Kconfig.debug-       depends on MCOUNT
> 
>     arch/x86/Kconfig.debug:config FRAME_POINTER
>     arch/x86/Kconfig.debug- depends on !UNWINDER_ORC && !UNWINDER_GUESS
>     arch/x86/Kconfig.debug- bool
> 
> Probably you need to adjust the following, too:
> 
>     lib/Kconfig.debug:config FRAME_POINTER
>     lib/Kconfig.debug-      bool "Compile the kernel with frame pointers"
>     lib/Kconfig.debug-      depends on DEBUG_KERNEL && (M68K || UML ||
> SUPERH) || ARCH_WANT_FRAME_POINTERS
>     lib/Kconfig.debug-      default y if (DEBUG_INFO && UML) ||
> ARCH_WANT_FRAME_POINTERS
> 
> i.e. drop SUPERH from the list above, and select ARCH_WANT_FRAME_POINTERS
> if !FUNCTION_TRACER.

Do you think you can send a patch for this change? I can then review and apply
it together with Randy's series in case everything works as expected.

Adrian

John Paul Adrian Glaubitz March 20, 2023, 8:09 p.m. UTC | #7

On Sun, 2023-03-05 at 20:00 -0800, Randy Dunlap wrote:
> Fix a build error in mcount.S when CONFIG_PRINTK is not enabled.
> Fixes this build error:
> 
> sh2-linux-ld: arch/sh/lib/mcount.o: in function `stack_panic':
> (.text+0xec): undefined reference to `dump_stack'
> 
> Fixes: e460ab27b6c3 ("sh: Fix up stack overflow check with ftrace disabled.")
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: Rich Felker <dalias@libc.org>
> Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: stable@vger.kernel.org
> ---
> v2: add PRINTK to STACK_DEBUG dependency (thanks, Geert)
> v3: skipped
> v4: refresh & resend
> 
>  arch/sh/Kconfig.debug |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff -- a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
> --- a/arch/sh/Kconfig.debug
> +++ b/arch/sh/Kconfig.debug
> @@ -15,7 +15,7 @@ config SH_STANDARD_BIOS
>  
>  config STACK_DEBUG
>  	bool "Check for stack overflows"
> -	depends on DEBUG_KERNEL
> +	depends on DEBUG_KERNEL && PRINTK
>  	help
>  	  This option will cause messages to be printed if free stack space
>  	  drops below a certain limit. Saying Y here will add overhead to

Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

John Paul Adrian Glaubitz March 20, 2023, 8:10 p.m. UTC | #8

Hi Geert!

On Mon, 2023-03-20 at 13:42 +0100, Geert Uytterhoeven wrote:
> Hi Adrian,
> 
> On Mon, Mar 20, 2023 at 10:13 AM John Paul Adrian Glaubitz
> <glaubitz@physik.fu-berlin.de> wrote:
> > On Mon, 2023-03-20 at 09:16 +0100, Geert Uytterhoeven wrote:
> > > On Sun, Mar 19, 2023 at 9:49 PM John Paul Adrian Glaubitz
> > > <glaubitz@physik.fu-berlin.de> wrote:
> > > > On Sun, 2023-03-05 at 20:00 -0800, Randy Dunlap wrote:
> > > > > Fix a build error in mcount.S when CONFIG_PRINTK is not enabled.
> > > > > Fixes this build error:
> > > > > 
> > > > > sh2-linux-ld: arch/sh/lib/mcount.o: in function `stack_panic':
> > > > > (.text+0xec): undefined reference to `dump_stack'
> > > > > 
> > > > > Fixes: e460ab27b6c3 ("sh: Fix up stack overflow check with ftrace disabled.")
> > > > > Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> > > > > Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> > > > > Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> > > > > Cc: Rich Felker <dalias@libc.org>
> > > > > Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> > > > > Cc: stable@vger.kernel.org
> > > > > ---
> > > > > v2: add PRINTK to STACK_DEBUG dependency (thanks, Geert)
> > > > > v3: skipped
> > > > > v4: refresh & resend
> > > > > 
> > > > >  arch/sh/Kconfig.debug |    2 +-
> > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > 
> > > > > diff -- a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
> > > > > --- a/arch/sh/Kconfig.debug
> > > > > +++ b/arch/sh/Kconfig.debug
> > > > > @@ -15,7 +15,7 @@ config SH_STANDARD_BIOS
> > > > > 
> > > > >  config STACK_DEBUG
> > > > >       bool "Check for stack overflows"
> > > > > -     depends on DEBUG_KERNEL
> > > > > +     depends on DEBUG_KERNEL && PRINTK
> > > > >       help
> > > > >         This option will cause messages to be printed if free stack space
> > > > >         drops below a certain limit. Saying Y here will add overhead to
> > > > 
> > > > I can't really test this change as the moment I am enabling CONFIG_STACK_DEBUG,
> > > > the build fails with:
> > > > 
> > > >   CC      scripts/mod/devicetable-offsets.s
> > > > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> > > > make[1]: *** [scripts/Makefile.build:252: scripts/mod/empty.o] Error 1
> > > > make[1]: *** Waiting for unfinished jobs....
> > > > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible
> > > > make[1]: *** [scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 1
> > > > make: *** [Makefile:1286: prepare0] Error 2
> > > > 
> > > > So, I assume we need to strip -fomit-frame-pointer from KBUILD_CFLAGS, correct?
> > > > 
> > > > I tried this change, but that doesn't fix it for me:
> > > > 
> > > > diff --git a/arch/sh/Makefile b/arch/sh/Makefile
> > > > index 5c8776482530..83f535b73835 100644
> > > > --- a/arch/sh/Makefile
> > > > +++ b/arch/sh/Makefile
> > > > @@ -173,6 +173,7 @@ KBUILD_AFLAGS               += $(cflags-y)
> > > > 
> > > >  ifeq ($(CONFIG_MCOUNT),y)
> > > >    KBUILD_CFLAGS += -pg
> > > > +  KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS))
> > > >  endif
> > > > 
> > > >  ifeq ($(CONFIG_DWARF_UNWINDER),y)
> > > > 
> > > > Any ideas?
> > > 
> > > Please try with "+=" instead of ":=".
> > 
> > That doesn't work either. I tried the following, but that didn't strip -fomit-frame-pointer:
> 
> Oops, obviously all of that happened before my morning coffee ;-)
> 
> Makefile has:
> 
>     ifdef CONFIG_FRAME_POINTER
>     KBUILD_CFLAGS   += -fno-omit-frame-pointer -fno-optimize-sibling-calls
>     KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y
>     else
>     # Some targets (ARM with Thumb2, for example), can't be built with frame
>     # pointers.  For those, we don't have FUNCTION_TRACER automatically
>     # select FRAME_POINTER.  However, FUNCTION_TRACER adds -pg, and this is
>     # incompatible with -fomit-frame-pointer with current GCC, so we don't use
>     # -fomit-frame-pointer with FUNCTION_TRACER.
>     # In the Rust target specification, "frame-pointer" is set explicitly
>     # to "may-omit".
>     ifndef CONFIG_FUNCTION_TRACER
>     KBUILD_CFLAGS   += -fomit-frame-pointer
>     endif
>     endif
> 
> Your config probably has CONFIG_FRAME_POINTER set?
> 
>     arch/sh/Kconfig.debug=config DWARF_UNWINDER
>     arch/sh/Kconfig.debug-  bool "Enable the DWARF unwinder for stacktraces"
>     arch/sh/Kconfig.debug-  depends on DEBUG_KERNEL
>     arch/sh/Kconfig.debug:  select FRAME_POINTER
> 
> You should make sure that cannot happen when CONFIG_FUNCTION_TRACER
> is enabled. I.e. make DWARF_UNWINDER depend on !FUNCTION_TRACER?
> 
> Other architectures do something similar:
> 
>     arch/sparc/Kconfig.debug:config FRAME_POINTER
>     arch/sparc/Kconfig.debug-       bool
>     arch/sparc/Kconfig.debug-       depends on MCOUNT
> 
>     arch/x86/Kconfig.debug:config FRAME_POINTER
>     arch/x86/Kconfig.debug- depends on !UNWINDER_ORC && !UNWINDER_GUESS
>     arch/x86/Kconfig.debug- bool
> 
> Probably you need to adjust the following, too:
> 
>     lib/Kconfig.debug:config FRAME_POINTER
>     lib/Kconfig.debug-      bool "Compile the kernel with frame pointers"
>     lib/Kconfig.debug-      depends on DEBUG_KERNEL && (M68K || UML ||
> SUPERH) || ARCH_WANT_FRAME_POINTERS
>     lib/Kconfig.debug-      default y if (DEBUG_INFO && UML) ||
> ARCH_WANT_FRAME_POINTERS
> 
> i.e. drop SUPERH from the list above, and select ARCH_WANT_FRAME_POINTERS
> if !FUNCTION_TRACER.

This change fixed it for me:

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 98e43a537826..04d310ee7384 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -55,6 +55,7 @@ config SUPERH
        select HAVE_SOFTIRQ_ON_OWN_STACK if IRQSTACKS
        select HAVE_STACKPROTECTOR
        select HAVE_SYSCALL_TRACEPOINTS
+       select ARCH_WANT_FRAME_POINTERS
        select IRQ_FORCED_THREADING
        select MODULES_USE_ELF_RELA
        select NEED_SG_DMA_LENGTH
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index c8b379e2e9ad..3cf45d8edace 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -523,7 +523,7 @@ config ARCH_WANT_FRAME_POINTERS
 
 config FRAME_POINTER
        bool "Compile the kernel with frame pointers"
-       depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
+       depends on DEBUG_KERNEL && (M68K || UML) || ARCH_WANT_FRAME_POINTERS
        default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
        help
          If you say Y here the resulting kernel image will be slightly

It seems this is also what the other architectures do it seems.

Adrian

diff mbox series

Patch

diff -- a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug
--- a/arch/sh/Kconfig.debug
+++ b/arch/sh/Kconfig.debug
@@ -15,7 +15,7 @@  config SH_STANDARD_BIOS
 
 config STACK_DEBUG
 	bool "Check for stack overflows"
-	depends on DEBUG_KERNEL
+	depends on DEBUG_KERNEL && PRINTK
 	help
 	  This option will cause messages to be printed if free stack space
 	  drops below a certain limit. Saying Y here will add overhead to