diff mbox

[v2,4/5] powerpc/kbuild: Use flags variables rather than overriding LD/CC/AS

Message ID 20180510051659.15356-5-npiggin@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Nicholas Piggin May 10, 2018, 5:16 a.m. UTC
The powerpc toolchain can compile combinations of 32/64 bit and
big/little endian, so it's convenient to consider, e.g.,

  `CC -m64 -mbig-endian`

To be the C compiler for the purpose of invoking it to build target
artifacts. So overriding the the CC variable to include thse flags
works for this purpose.

Unfortunately that is not compatible with the way the proposed new
Kconfig macro language will work.

After previous patches in this series, these flags can be carefully
passed in using flags instead.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/Makefile   | 16 +++++++++-------
 scripts/recordmcount.pl |  8 ++++++++
 2 files changed, 17 insertions(+), 7 deletions(-)

Comments

Michael Ellerman May 10, 2018, 1:03 p.m. UTC | #1
Nicholas Piggin <npiggin@gmail.com> writes:

> The powerpc toolchain can compile combinations of 32/64 bit and
> big/little endian, so it's convenient to consider, e.g.,
>
>   `CC -m64 -mbig-endian`
>
> To be the C compiler for the purpose of invoking it to build target
> artifacts. So overriding the the CC variable to include thse flags
> works for this purpose.
>
> Unfortunately that is not compatible with the way the proposed new
> Kconfig macro language will work.
>
> After previous patches in this series, these flags can be carefully
> passed in using flags instead.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  arch/powerpc/Makefile   | 16 +++++++++-------
>  scripts/recordmcount.pl |  8 ++++++++

We should probably at least Cc Rostedt on the recordmcount.pl change.

> diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
> index 191eb949d52c..919711dd9d6c 100755
> --- a/scripts/recordmcount.pl
> +++ b/scripts/recordmcount.pl
> @@ -274,6 +274,14 @@ if ($arch eq "x86_64") {

Despite what the above says you're patching the powerpc entry AFAICS, so
I guess that's pretty harmless.

>      if ($bits == 64) {
>  	$type = ".quad";
>      }
> +    $ld .= " -EB ";
> +    if ($endian eq "big") {
> +	    $cc .= " -mbig-endian ";
> +	    $ld .= " -EB ";

Don't we end up with two "-EB"s for the big endian case?

Or do I understand perl even less than I thought I did?

> +    } else {
> +	    $cc .= " -mlittle-endian ";
> +	    $ld .= " -EL ";
> +    }
>  
>  } elsif ($arch eq "arm") {
>      $alignment = 2;

cheers
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Nicholas Piggin May 10, 2018, 1:11 p.m. UTC | #2
On Thu, 10 May 2018 23:03:08 +1000
Michael Ellerman <mpe@ellerman.id.au> wrote:

> Nicholas Piggin <npiggin@gmail.com> writes:
> 
> > The powerpc toolchain can compile combinations of 32/64 bit and
> > big/little endian, so it's convenient to consider, e.g.,
> >
> >   `CC -m64 -mbig-endian`
> >
> > To be the C compiler for the purpose of invoking it to build target
> > artifacts. So overriding the the CC variable to include thse flags
> > works for this purpose.
> >
> > Unfortunately that is not compatible with the way the proposed new
> > Kconfig macro language will work.
> >
> > After previous patches in this series, these flags can be carefully
> > passed in using flags instead.
> >
> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> > ---
> >  arch/powerpc/Makefile   | 16 +++++++++-------
> >  scripts/recordmcount.pl |  8 ++++++++  
> 
> We should probably at least Cc Rostedt on the recordmcount.pl change.

Sure I'll send another iteration after some more time for reviews and
cc him on it.

> 
> > diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
> > index 191eb949d52c..919711dd9d6c 100755
> > --- a/scripts/recordmcount.pl
> > +++ b/scripts/recordmcount.pl
> > @@ -274,6 +274,14 @@ if ($arch eq "x86_64") {  
> 
> Despite what the above says you're patching the powerpc entry AFAICS, so
> I guess that's pretty harmless.

Yeah I didn't think it was worth a separate patch.

> 
> >      if ($bits == 64) {
> >  	$type = ".quad";
> >      }
> > +    $ld .= " -EB ";
> > +    if ($endian eq "big") {
> > +	    $cc .= " -mbig-endian ";
> > +	    $ld .= " -EB ";  
> 
> Don't we end up with two "-EB"s for the big endian case?
> 
> Or do I understand perl even less than I thought I did?

No I was testing things and that's leaked into the commit. Good eye. I
think it worked for le because the next -EL will override the first -EB,
but I'll take that out.

Thanks,
Nick
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diff mbox

Patch

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index a40f59ca2afe..5f3ec8029e50 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -70,13 +70,15 @@  endif
 endif
 
 ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)
-override LD	+= -EL
+KBUILD_CFLAGS	+= -mlittle-endian
+LDFLAGS		+= -EL
 LDEMULATION	:= lppc
 GNUTARGET	:= powerpcle
 MULTIPLEWORD	:= -mno-multiple
 KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-save-toc-indirect)
 else
-override LD	+= -EB
+KBUILD_CFLAGS += $(call cc-option,-mbig-endian)
+LDFLAGS		+= -EB
 LDEMULATION	:= ppc
 GNUTARGET	:= powerpc
 MULTIPLEWORD	:= -mmultiple
@@ -89,19 +91,19 @@  aflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mabi=elfv1)
 aflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mabi=elfv2
 endif
 
-cflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mlittle-endian
-cflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mbig-endian)
 ifneq ($(cc-name),clang)
   cflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mno-strict-align
 endif
 
+cflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mbig-endian)
+cflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mlittle-endian
 aflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mbig-endian)
 aflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mlittle-endian
 
 ifeq ($(HAS_BIARCH),y)
-override AS	+= -a$(BITS)
-override LD	+= -m elf$(BITS)$(LDEMULATION)
-override CC	+= -m$(BITS)
+KBUILD_CFLAGS	+= -m$(BITS)
+KBUILD_AFLAGS	+= -m$(BITS) -Wl,-a$(BITS)
+LDFLAGS		+= -m elf$(BITS)$(LDEMULATION)
 KBUILD_ARFLAGS	+= --target=elf$(BITS)-$(GNUTARGET)
 endif
 
diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index 191eb949d52c..919711dd9d6c 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -274,6 +274,14 @@  if ($arch eq "x86_64") {
     if ($bits == 64) {
 	$type = ".quad";
     }
+    $ld .= " -EB ";
+    if ($endian eq "big") {
+	    $cc .= " -mbig-endian ";
+	    $ld .= " -EB ";
+    } else {
+	    $cc .= " -mlittle-endian ";
+	    $ld .= " -EL ";
+    }
 
 } elsif ($arch eq "arm") {
     $alignment = 2;