diff mbox series

[v5,11/17] kbuild: Add generic hook for architectures to use before the final vmlinux link

Message ID 20240915205648.830121-12-hbathini@linux.ibm.com (mailing list archive)
State Superseded
Headers show
Series powerpc: Core ftrace rework, support for ftrace direct and bpf trampolines | expand

Commit Message

Hari Bathini Sept. 15, 2024, 8:56 p.m. UTC 
From: Naveen N Rao <naveen@kernel.org>

On powerpc, we would like to be able to make a pass on vmlinux.o and
generate a new object file to be linked into vmlinux. Add a generic pass
in Makefile.vmlinux that architectures can use for this purpose.

Architectures need to select CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX and must
provide arch/<arch>/tools/Makefile with .arch.vmlinux.o target, which
will be invoked prior to the final vmlinux link step.

Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---

Changes in v5:
* Intermediate files named .vmlinux.arch.* instead of .arch.vmlinux.*


 arch/Kconfig             | 6 ++++++
 scripts/Makefile.vmlinux | 7 +++++++
 scripts/link-vmlinux.sh  | 7 ++++++-
 3 files changed, 19 insertions(+), 1 deletion(-)

Comments

Masahiro Yamada Oct. 9, 2024, 3:23 p.m. UTC | #1 
On Mon, Sep 16, 2024 at 5:58 AM Hari Bathini <hbathini@linux.ibm.com> wrote:
>
> From: Naveen N Rao <naveen@kernel.org>
>
> On powerpc, we would like to be able to make a pass on vmlinux.o and
> generate a new object file to be linked into vmlinux. Add a generic pass
> in Makefile.vmlinux that architectures can use for this purpose.
>
> Architectures need to select CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX and must
> provide arch/<arch>/tools/Makefile with .arch.vmlinux.o target, which
> will be invoked prior to the final vmlinux link step.
>
> Signed-off-by: Naveen N Rao <naveen@kernel.org>
> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
> ---
>
> Changes in v5:
> * Intermediate files named .vmlinux.arch.* instead of .arch.vmlinux.*
>
>
>  arch/Kconfig             | 6 ++++++
>  scripts/Makefile.vmlinux | 7 +++++++
>  scripts/link-vmlinux.sh  | 7 ++++++-
>  3 files changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 975dd22a2dbd..ef868ff8156a 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -1643,4 +1643,10 @@ config CC_HAS_SANE_FUNCTION_ALIGNMENT
>  config ARCH_NEED_CMPXCHG_1_EMU
>         bool
>
> +config ARCH_WANTS_PRE_LINK_VMLINUX
> +       def_bool n


Redundant default. This line should be "bool".






> +       help
> +         An architecture can select this if it provides arch/<arch>/tools/Makefile
> +         with .arch.vmlinux.o target to be linked into vmlinux.
> +
>  endmenu
> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
> index 49946cb96844..edf6fae8d960 100644
> --- a/scripts/Makefile.vmlinux
> +++ b/scripts/Makefile.vmlinux
> @@ -22,6 +22,13 @@ targets += .vmlinux.export.o
>  vmlinux: .vmlinux.export.o
>  endif
>
> +ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX
> +vmlinux: arch/$(SRCARCH)/tools/.vmlinux.arch.o

If you move this to arch/*/tools/, there is no reason
to make it a hidden file.


vmlinux: arch/$(SRCARCH)/tools/vmlinux.arch.o




> +arch/$(SRCARCH)/tools/.vmlinux.arch.o: vmlinux.o

FORCE is missing.


arch/$(SRCARCH)/tools/vmlinux.arch.o: vmlinux.o FORCE



> +       $(Q)$(MAKE) $(build)=arch/$(SRCARCH)/tools $@
> +endif
> +
>  ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
>
>  # Final link of vmlinux with optional arch pass after final link
> diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
> index f7b2503cdba9..b3a940c0e6c2 100755
> --- a/scripts/link-vmlinux.sh
> +++ b/scripts/link-vmlinux.sh
> @@ -100,7 +100,7 @@ vmlinux_link()
>         ${ld} ${ldflags} -o ${output}                                   \
>                 ${wl}--whole-archive ${objs} ${wl}--no-whole-archive    \
>                 ${wl}--start-group ${libs} ${wl}--end-group             \
> -               ${kallsymso} ${btf_vmlinux_bin_o} ${ldlibs}
> +               ${kallsymso} ${btf_vmlinux_bin_o} ${arch_vmlinux_o} ${ldlibs}
>  }
>
>  # generate .BTF typeinfo from DWARF debuginfo
> @@ -214,6 +214,11 @@ fi
>
>  ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o
>
> +arch_vmlinux_o=""
> +if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then
> +       arch_vmlinux_o=arch/${SRCARCH}/tools/.vmlinux.arch.o


arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.o



> +fi
> +
>  btf_vmlinux_bin_o=
>  kallsymso=
>  strip_debug=
> --
> 2.46.0
>


--
Best Regards
Masahiro Yamada
Hari Bathini Oct. 10, 2024, 9:56 a.m. UTC | #2 
On 09/10/24 8:53 pm, Masahiro Yamada wrote:
> On Mon, Sep 16, 2024 at 5:58 AM Hari Bathini <hbathini@linux.ibm.com> wrote:
>>
>> From: Naveen N Rao <naveen@kernel.org>
>>
>> On powerpc, we would like to be able to make a pass on vmlinux.o and
>> generate a new object file to be linked into vmlinux. Add a generic pass
>> in Makefile.vmlinux that architectures can use for this purpose.
>>
>> Architectures need to select CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX and must
>> provide arch/<arch>/tools/Makefile with .arch.vmlinux.o target, which
>> will be invoked prior to the final vmlinux link step.
>>
>> Signed-off-by: Naveen N Rao <naveen@kernel.org>
>> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
>> ---
>>
>> Changes in v5:
>> * Intermediate files named .vmlinux.arch.* instead of .arch.vmlinux.*
>>
>>
>>   arch/Kconfig             | 6 ++++++
>>   scripts/Makefile.vmlinux | 7 +++++++
>>   scripts/link-vmlinux.sh  | 7 ++++++-
>>   3 files changed, 19 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/Kconfig b/arch/Kconfig
>> index 975dd22a2dbd..ef868ff8156a 100644
>> --- a/arch/Kconfig
>> +++ b/arch/Kconfig
>> @@ -1643,4 +1643,10 @@ config CC_HAS_SANE_FUNCTION_ALIGNMENT
>>   config ARCH_NEED_CMPXCHG_1_EMU
>>          bool
>>
>> +config ARCH_WANTS_PRE_LINK_VMLINUX
>> +       def_bool n
> 
> 
> Redundant default. This line should be "bool".
> 
> 
> 
> 
> 
> 
>> +       help
>> +         An architecture can select this if it provides arch/<arch>/tools/Makefile
>> +         with .arch.vmlinux.o target to be linked into vmlinux.
>> +
>>   endmenu
>> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
>> index 49946cb96844..edf6fae8d960 100644
>> --- a/scripts/Makefile.vmlinux
>> +++ b/scripts/Makefile.vmlinux
>> @@ -22,6 +22,13 @@ targets += .vmlinux.export.o
>>   vmlinux: .vmlinux.export.o
>>   endif
>>
>> +ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX
>> +vmlinux: arch/$(SRCARCH)/tools/.vmlinux.arch.o
> 
> If you move this to arch/*/tools/, there is no reason
> to make it a hidden file.

Thanks for reviewing and the detailed comments, Masahiro.

> 
> 
> vmlinux: arch/$(SRCARCH)/tools/vmlinux.arch.o
> 
> 
> 
> 
>> +arch/$(SRCARCH)/tools/.vmlinux.arch.o: vmlinux.o
> 
> FORCE is missing.


I dropped FORCE as it was rebuilding vmlinux on every invocation
of `make` irrespective of whether vmlinux.o changed or not..
Just curious if the changes you suggested makes FORCE necessary
or FORCE was expected even without the other changes you suggested?

Thanks
Hari
Masahiro Yamada Oct. 10, 2024, 11:37 a.m. UTC | #3 
On Thu, Oct 10, 2024 at 6:57 PM Hari Bathini <hbathini@linux.ibm.com> wrote:
>
>
> On 09/10/24 8:53 pm, Masahiro Yamada wrote:
> > On Mon, Sep 16, 2024 at 5:58 AM Hari Bathini <hbathini@linux.ibm.com> wrote:
> >>
> >> From: Naveen N Rao <naveen@kernel.org>
> >>
> >> On powerpc, we would like to be able to make a pass on vmlinux.o and
> >> generate a new object file to be linked into vmlinux. Add a generic pass
> >> in Makefile.vmlinux that architectures can use for this purpose.
> >>
> >> Architectures need to select CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX and must
> >> provide arch/<arch>/tools/Makefile with .arch.vmlinux.o target, which
> >> will be invoked prior to the final vmlinux link step.
> >>
> >> Signed-off-by: Naveen N Rao <naveen@kernel.org>
> >> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
> >> ---
> >>
> >> Changes in v5:
> >> * Intermediate files named .vmlinux.arch.* instead of .arch.vmlinux.*
> >>
> >>
> >>   arch/Kconfig             | 6 ++++++
> >>   scripts/Makefile.vmlinux | 7 +++++++
> >>   scripts/link-vmlinux.sh  | 7 ++++++-
> >>   3 files changed, 19 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/arch/Kconfig b/arch/Kconfig
> >> index 975dd22a2dbd..ef868ff8156a 100644
> >> --- a/arch/Kconfig
> >> +++ b/arch/Kconfig
> >> @@ -1643,4 +1643,10 @@ config CC_HAS_SANE_FUNCTION_ALIGNMENT
> >>   config ARCH_NEED_CMPXCHG_1_EMU
> >>          bool
> >>
> >> +config ARCH_WANTS_PRE_LINK_VMLINUX
> >> +       def_bool n
> >
> >
> > Redundant default. This line should be "bool".
> >
> >
> >
> >
> >
> >
> >> +       help
> >> +         An architecture can select this if it provides arch/<arch>/tools/Makefile
> >> +         with .arch.vmlinux.o target to be linked into vmlinux.
> >> +
> >>   endmenu
> >> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
> >> index 49946cb96844..edf6fae8d960 100644
> >> --- a/scripts/Makefile.vmlinux
> >> +++ b/scripts/Makefile.vmlinux
> >> @@ -22,6 +22,13 @@ targets += .vmlinux.export.o
> >>   vmlinux: .vmlinux.export.o
> >>   endif
> >>
> >> +ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX
> >> +vmlinux: arch/$(SRCARCH)/tools/.vmlinux.arch.o
> >
> > If you move this to arch/*/tools/, there is no reason
> > to make it a hidden file.
>
> Thanks for reviewing and the detailed comments, Masahiro.
>
> >
> >
> > vmlinux: arch/$(SRCARCH)/tools/vmlinux.arch.o
> >
> >
> >
> >
> >> +arch/$(SRCARCH)/tools/.vmlinux.arch.o: vmlinux.o
> >
> > FORCE is missing.
>
>
> I dropped FORCE as it was rebuilding vmlinux on every invocation
> of `make` irrespective of whether vmlinux.o changed or not..


It is because you did not add vmlinux.arch.S to 'targets'

See my comment in 12/17.

  targets += vmlinux.arch.S


> Just curious if the changes you suggested makes FORCE necessary
> or FORCE was expected even without the other changes you suggested?


FORCE is necessary.

arch/powerpc/tools/Makefile must be checked every time.


When arch/powerpc/tools/ftrace-gen-ool-stubs.sh is changed,
vmlinux must be relinked.





> Thanks
> Hari




--
Best Regards
Masahiro Yamada
Hari Bathini Oct. 24, 2024, 5:20 p.m. UTC | #4 
Hello Masahiro,

On 10/10/24 5:07 pm, Masahiro Yamada wrote:
> On Thu, Oct 10, 2024 at 6:57 PM Hari Bathini <hbathini@linux.ibm.com> wrote:
>>
>>
>> On 09/10/24 8:53 pm, Masahiro Yamada wrote:
>>> On Mon, Sep 16, 2024 at 5:58 AM Hari Bathini <hbathini@linux.ibm.com> wrote:
>>>>
>>>> From: Naveen N Rao <naveen@kernel.org>
>>>>
>>>> On powerpc, we would like to be able to make a pass on vmlinux.o and
>>>> generate a new object file to be linked into vmlinux. Add a generic pass
>>>> in Makefile.vmlinux that architectures can use for this purpose.
>>>>
>>>> Architectures need to select CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX and must
>>>> provide arch/<arch>/tools/Makefile with .arch.vmlinux.o target, which
>>>> will be invoked prior to the final vmlinux link step.
>>>>
>>>> Signed-off-by: Naveen N Rao <naveen@kernel.org>
>>>> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
>>>> ---
>>>>
>>>> Changes in v5:
>>>> * Intermediate files named .vmlinux.arch.* instead of .arch.vmlinux.*
>>>>
>>>>
>>>>    arch/Kconfig             | 6 ++++++
>>>>    scripts/Makefile.vmlinux | 7 +++++++
>>>>    scripts/link-vmlinux.sh  | 7 ++++++-
>>>>    3 files changed, 19 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/arch/Kconfig b/arch/Kconfig
>>>> index 975dd22a2dbd..ef868ff8156a 100644
>>>> --- a/arch/Kconfig
>>>> +++ b/arch/Kconfig
>>>> @@ -1643,4 +1643,10 @@ config CC_HAS_SANE_FUNCTION_ALIGNMENT
>>>>    config ARCH_NEED_CMPXCHG_1_EMU
>>>>           bool
>>>>
>>>> +config ARCH_WANTS_PRE_LINK_VMLINUX
>>>> +       def_bool n
>>>
>>>
>>> Redundant default. This line should be "bool".
>>>
>>>
>>>
>>>
>>>
>>>
>>>> +       help
>>>> +         An architecture can select this if it provides arch/<arch>/tools/Makefile
>>>> +         with .arch.vmlinux.o target to be linked into vmlinux.
>>>> +
>>>>    endmenu
>>>> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
>>>> index 49946cb96844..edf6fae8d960 100644
>>>> --- a/scripts/Makefile.vmlinux
>>>> +++ b/scripts/Makefile.vmlinux
>>>> @@ -22,6 +22,13 @@ targets += .vmlinux.export.o
>>>>    vmlinux: .vmlinux.export.o
>>>>    endif
>>>>
>>>> +ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX
>>>> +vmlinux: arch/$(SRCARCH)/tools/.vmlinux.arch.o
>>>
>>> If you move this to arch/*/tools/, there is no reason
>>> to make it a hidden file.
>>
>> Thanks for reviewing and the detailed comments, Masahiro.
>>
>>>
>>>
>>> vmlinux: arch/$(SRCARCH)/tools/vmlinux.arch.o
>>>
>>>
>>>
>>>
>>>> +arch/$(SRCARCH)/tools/.vmlinux.arch.o: vmlinux.o
>>>
>>> FORCE is missing.
>>
>>
>> I dropped FORCE as it was rebuilding vmlinux on every invocation
>> of `make` irrespective of whether vmlinux.o changed or not..
> 
> 
> It is because you did not add vmlinux.arch.S to 'targets'
> 
> See my comment in 12/17.
> 
>    targets += vmlinux.arch.S
> 
> 
>> Just curious if the changes you suggested makes FORCE necessary
>> or FORCE was expected even without the other changes you suggested?
> 
> 
> FORCE is necessary.
> 
> arch/powerpc/tools/Makefile must be checked every time.
> 
> 
> When arch/powerpc/tools/ftrace-gen-ool-stubs.sh is changed,
> vmlinux must be relinked.

Thanks for the review and clarifications!
Posted v6 with the changes. Please review:

  
https://lore.kernel.org/all/20241018173632.277333-1-hbathini@linux.ibm.com/

- Hari
diff mbox series

Patch

diff --git a/arch/Kconfig b/arch/Kconfig
index 975dd22a2dbd..ef868ff8156a 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1643,4 +1643,10 @@  config CC_HAS_SANE_FUNCTION_ALIGNMENT
 config ARCH_NEED_CMPXCHG_1_EMU
 	bool
 
+config ARCH_WANTS_PRE_LINK_VMLINUX
+	def_bool n
+	help
+	  An architecture can select this if it provides arch/<arch>/tools/Makefile
+	  with .arch.vmlinux.o target to be linked into vmlinux.
+
 endmenu
diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
index 49946cb96844..edf6fae8d960 100644
--- a/scripts/Makefile.vmlinux
+++ b/scripts/Makefile.vmlinux
@@ -22,6 +22,13 @@  targets += .vmlinux.export.o
 vmlinux: .vmlinux.export.o
 endif
 
+ifdef CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX
+vmlinux: arch/$(SRCARCH)/tools/.vmlinux.arch.o
+
+arch/$(SRCARCH)/tools/.vmlinux.arch.o: vmlinux.o
+	$(Q)$(MAKE) $(build)=arch/$(SRCARCH)/tools $@
+endif
+
 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
 
 # Final link of vmlinux with optional arch pass after final link
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index f7b2503cdba9..b3a940c0e6c2 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -100,7 +100,7 @@  vmlinux_link()
 	${ld} ${ldflags} -o ${output}					\
 		${wl}--whole-archive ${objs} ${wl}--no-whole-archive	\
 		${wl}--start-group ${libs} ${wl}--end-group		\
-		${kallsymso} ${btf_vmlinux_bin_o} ${ldlibs}
+		${kallsymso} ${btf_vmlinux_bin_o} ${arch_vmlinux_o} ${ldlibs}
 }
 
 # generate .BTF typeinfo from DWARF debuginfo
@@ -214,6 +214,11 @@  fi
 
 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o
 
+arch_vmlinux_o=""
+if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then
+	arch_vmlinux_o=arch/${SRCARCH}/tools/.vmlinux.arch.o
+fi
+
 btf_vmlinux_bin_o=
 kallsymso=
 strip_debug=