powerpc/kbuild: Use flags variables rather than overriding LD/CC/AS

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 CC variable to include these 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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/Makefile

@@ -75,13 +75,15 @@ 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 += $(call cc-option,-mbig-endian)
+LDFLAGS		+= -EB
 LDEMULATION	:= ppc
 GNUTARGET	:= powerpc
 MULTIPLEWORD	:= -mmultiple
@@ -94,19 +96,19 @@ aflags-$(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
 

arch/powerpc/tools/gcc-check-mprofile-kernel.sh

@@ -7,17 +7,21 @@ set -o pipefail
 # To debug, uncomment the following line
 # set -x
 
+# -mprofile-kernel is only supported on 64le, so this should not be invoked
+# for other targets. Therefore we can pass in -m64 and -mlittle-endian
+# explicitly, to take care of toolchains defaulting to other targets.
+
 # Test whether the compile option -mprofile-kernel exists and generates
 # profiling code (ie. a call to _mcount()).
 echo "int func() { return 0; }" | \
-    $* -S -x c -O2 -p -mprofile-kernel - -o - 2> /dev/null | \
-    grep -q "_mcount"
+    $* -m64 -mlittle-endian -S -x c -O2 -p -mprofile-kernel - -o - \
+    2> /dev/null | grep -q "_mcount"
 
 # Test whether the notrace attribute correctly suppresses calls to _mcount().
 
 echo -e "#include <linux/compiler.h>\nnotrace int func() { return 0; }" | \
-    $* -S -x c -O2 -p -mprofile-kernel - -o - 2> /dev/null | \
-    grep -q "_mcount" && \
+    $* -m64 -mlittle-endian -S -x c -O2 -p -mprofile-kernel - -o - \
+    2> /dev/null | grep -q "_mcount" && \
     exit 1
 
 echo "OK"

scripts/recordmcount.pl

@@ -266,13 +266,29 @@ if ($arch eq "x86_64") {
     $objcopy .= " -O elf32-sh-linux";
 
 } elsif ($arch eq "powerpc") {
+    my $ldemulation;
+
     $local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
     # See comment in the sparc64 section for why we use '\w'.
     $function_regex = "^([0-9a-fA-F]+)\\s+<(\\.?\\w*?)>:";
     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s\\.?_mcount\$";
 
+    if ($endian eq "big") {
+	    $cc .= " -mbig-endian ";
+	    $ld .= " -EB ";
+	    $ldemulation = "ppc"
+    } else {
+	    $cc .= " -mlittle-endian ";
+	    $ld .= " -EL ";
+	    $ldemulation = "lppc"
+    }
     if ($bits == 64) {
-	$type = ".quad";
+        $type = ".quad";
+        $cc .= " -m64 ";
+        $ld .= " -m elf64".$ldemulation." ";
+    } else {
+        $cc .= " -m32 ";
+        $ld .= " -m elf32".$ldemulation." ";
     }
 
 } elsif ($arch eq "arm") {