From 56f1bd12c92806fd18337ba4cd3c0a8d714d0e94 Mon Sep 17 00:00:00 2001
From: Andreas Arnez <arnez@linux.ibm.com>
Date: Thu, 15 Jun 2023 17:24:53 +0200
Subject: [PATCH] Bug 470978 - s390x: Link the tools with -Wl,--s390-pgste

Programs that require the PGSTE mode to be enabled may currently fail
under Valgrind.  In particular this affects qemu-kvm.

While it is also possible to enable the PGSTE mode globally with

  sysctl vm.allocate_psgte=1

the problem can more easily be prevented by linking the Valgrind tools
with -Wl,--s390-pgste.  Add a configure check if the linker supports this,
and activate the flag if it does.

To verify the intended result, the following shell command can be used to
list the executables having this flag set:

  find . -type f -perm -u+x -execdir \
       /bin/sh -c 'readelf -lW $0 2>/dev/null | grep PGSTE' {} \; -print
---
 Makefile.tool.am |  2 +-
 configure.ac     | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/Makefile.tool.am b/Makefile.tool.am
index df9502913..4ce6d5ab0 100644
--- a/Makefile.tool.am
+++ b/Makefile.tool.am
@@ -78,7 +78,7 @@ TOOL_LDFLAGS_ARM64_LINUX = \
 	$(TOOL_LDFLAGS_COMMON_LINUX) @FLAG_M64@
 
 TOOL_LDFLAGS_S390X_LINUX = \
-	$(TOOL_LDFLAGS_COMMON_LINUX) @FLAG_M64@
+	$(TOOL_LDFLAGS_COMMON_LINUX) @FLAG_M64@ @FLAG_S390_PGSTE@
 
 TOOL_LDFLAGS_X86_DARWIN = \
 	$(TOOL_LDFLAGS_COMMON_DARWIN) -arch i386
diff --git a/configure.ac b/configure.ac
index 0cf84a1c0..1d4164a7d 100755
--- a/configure.ac
+++ b/configure.ac
@@ -3096,6 +3096,26 @@ AC_SUBST([FLAG_NO_BUILD_ID], [""])
 fi
 CFLAGS=$safe_CFLAGS
 
+# On s390x, if the linker supports -Wl,--s390-pgste, then we build the
+# tools with that flag.  This enables running programs that need it, such
+# as qemu-kvm.
+if test x$VGCONF_PLATFORM_PRI_CAPS = xS390X_LINUX; then
+AC_MSG_CHECKING([if the linker accepts -Wl,--s390-pgste])
+safe_CFLAGS=$CFLAGS
+CFLAGS="-Wl,--s390-pgste"
+
+AC_LINK_IFELSE(
+[AC_LANG_PROGRAM([ ], [return 0;])],
+[
+  AC_SUBST([FLAG_S390_PGSTE], ["-Wl,--s390-pgste"])
+  AC_MSG_RESULT([yes])
+], [
+  AC_SUBST([FLAG_S390_PGSTE], [""])
+  AC_MSG_RESULT([no])
+])
+CFLAGS=$safe_CFLAGS
+fi
+
 # does the ppc assembler support "mtocrf" et al?
 AC_MSG_CHECKING([if ppc32/64 as supports mtocrf/mfocrf])
 
-- 
2.40.1