[PATCH] powerpc/wrapper: add "-z rodynamic" when using LLD

From: Bill Wendling <morbo@google.com>
To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@lists.ozlabs.org
Cc: Nick Desaulniers <ndesaulniers@google.com>,
	Bill Wendling <morbo@google.com>,
	Fangrui Song <maskray@google.com>, Alan Modra <amodra@gmail.com>
Subject: [PATCH] powerpc/wrapper: add "-z rodynamic" when using LLD
Date: Wed, 18 Nov 2020 14:39:10 -0800	[thread overview]
Message-ID: <20201118223910.2711337-1-morbo@google.com> (raw)
In-Reply-To: <20201017000151.150788-1-morbo@google.com>

Normally all read-only sections precede SHF_WRITE sections. .dynamic and
.got have the SHF_WRITE flag; .dynamic probably because of DT_DEBUG. LLD
emits an error when this happens, so use "-z rodynamic" to mark .dynamic
as read-only.

Cc: Fangrui Song <maskray@google.com>
Cc: Alan Modra <amodra@gmail.com>
Signed-off-by: Bill Wendling <morbo@google.com>
---
 arch/powerpc/boot/wrapper | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/wrapper b/arch/powerpc/boot/wrapper
index cd58a62e810d..e1194955adbb 100755
--- a/arch/powerpc/boot/wrapper
+++ b/arch/powerpc/boot/wrapper
@@ -46,6 +46,7 @@ compression=.gz
 uboot_comp=gzip
 pie=
 format=
+rodynamic=
 
 # cross-compilation prefix
 CROSS=
@@ -353,6 +354,7 @@ epapr)
     platformo="$object/pseries-head.o $object/epapr.o $object/epapr-wrapper.o"
     link_address='0x20000000'
     pie=-pie
+    rodynamic=$(if ${CROSS}ld -V 2>&1 | grep -q LLD ; then echo "-z rodynamic"; fi)
     ;;
 mvme5100)
     platformo="$object/fixed-head.o $object/mvme5100.o"
@@ -493,7 +495,7 @@ if [ "$platform" != "miboot" ]; then
         text_start="-Ttext $link_address"
     fi
 #link everything
-    ${CROSS}ld -m $format -T $lds $text_start $pie $nodl -o "$ofile" $map \
+    ${CROSS}ld -m $format -T $lds $text_start $pie $nodl $rodynamic -o "$ofile" $map \
 	$platformo $tmp $object/wrapper.a
     rm $tmp
 fi
-- 
2.29.2.454.gaff20da3a2-goog

