Add install check for OpenMP{,-V}

See: https://lkml.org/lkml/2025/4/9/1709

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1767634882,
-        "narHash": "sha256-2GffSfQxe3sedHzK+sTKlYo/NTIAGzbFCIsNMUPAAnk=",
+        "lastModified": 1764522689,
+        "narHash": "sha256-SqUuBFjhl/kpDiVaKLQBoD8TLD+/cTUzzgVFoaHrkqY=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "3c9db02515ef1d9b6b709fc60ba9a540957f661c",
+        "rev": "8bb5646e0bed5dbd3ab08c7a7cc15b75ab4e1d0f",
         "type": "github"
       },
       "original": {

m/apex/configuration.nix

@@ -57,18 +57,6 @@
     };
   };
 
-  services.fail2ban = {
-    enable = true;
-    maxretry = 5;
-    bantime-increment = {
-      enable = true; # Double ban time on each attack
-      maxtime = "7d"; # Ban up to a week
-    };
-  };
-
-  # Disable SSH login with password, allow only keypair
-  services.openssh.settings.PasswordAuthentication = false;
-
   networking.firewall = {
     extraCommands = ''
       # Blackhole BSC vulnerability scanner (OpenVAS) as it is spamming our

m/bay/configuration.nix

@@ -24,7 +24,7 @@
       address = "10.0.40.40";
       prefixLength = 24;
     } ];
-    interfaces.ibs785.ipv4.addresses = [ {
+    interfaces.ibp5s0.ipv4.addresses = [ {
       address = "10.0.42.40";
       prefixLength = 24;
     } ];

m/common/base/users.nix

@@ -139,7 +139,6 @@
         openssh.authorizedKeys.keys = [
           "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKGt0ESYxekBiHJQowmKpfdouw0hVm3N7tUMtAaeLejK vincent@varch"
         ];
-        shell = pkgs.zsh;
       };
 
       pmartin1 = {

m/eudy/kernel/perf.nix

@@ -1,6 +1,11 @@
-{ pkgs, lib, ... }:
+{ config, pkgs, lib, ... }:
 
 {
+  # add the perf tool
+  environment.systemPackages = with pkgs; [
+    config.boot.kernelPackages.perf
+  ];
+
   # allow non-root users to read tracing data from the kernel
   boot.kernel.sysctl."kernel.perf_event_paranoid" = -2;
   boot.kernel.sysctl."kernel.kptr_restrict" = 0;

m/hut/configuration.nix

@@ -45,7 +45,7 @@
       address = "10.0.40.7";
       prefixLength = 24;
     } ];
-    interfaces.ibs785.ipv4.addresses = [ {
+    interfaces.ibp5s0.ipv4.addresses = [ {
       address = "10.0.42.7";
       prefixLength = 24;
     } ];

m/lake2/configuration.nix

@@ -46,7 +46,7 @@
       address = "10.0.40.42";
       prefixLength = 24;
     } ];
-    interfaces.ibs785.ipv4.addresses = [ {
+    interfaces.ibp5s0.ipv4.addresses = [ {
       address = "10.0.42.42";
       prefixLength = 24;
     } ];

m/owl1/configuration.nix

@@ -20,7 +20,7 @@
       address = "10.0.40.1";
       prefixLength = 24;
     } ];
-    interfaces.ibs785.ipv4.addresses = [ {
+    interfaces.ibp5s0.ipv4.addresses = [ {
       address = "10.0.42.1";
       prefixLength = 24;
     } ];

m/owl2/configuration.nix

@@ -21,7 +21,7 @@
       prefixLength = 24;
     } ];
     # Watch out! The OmniPath device is not in the same place here:
-    interfaces.ibs801.ipv4.addresses = [ {
+    interfaces.ibp129s0.ipv4.addresses = [ {
       address = "10.0.42.2";
       prefixLength = 24;
     } ];

m/tent/gitea.nix

@@ -27,7 +27,4 @@
       };
     };
   };
-
-  # Allow gitea user to send mail
-  users.users.gitea.extraGroups = [ "mail-robot" ];
 }

overlay.nix

@@ -12,9 +12,9 @@ let
     bench6 = callPackage ./pkgs/bench6/default.nix { };
     bigotes = callPackage ./pkgs/bigotes/default.nix { };
     clangOmpss2 = callPackage ./pkgs/llvm-ompss2/default.nix { };
-    clangOmpss2Nanos6 = callPackage ./pkgs/llvm-ompss2/default.nix { useNanos6 = true; };
-    clangOmpss2Nodes = callPackage ./pkgs/llvm-ompss2/default.nix { useNodes = true; useOpenmp = true; };
-    clangOmpss2NodesOmpv = callPackage ./pkgs/llvm-ompss2/default.nix { useNodes = true; useOpenmpV = true; };
+    clangOmpss2Nanos6 = callPackage ./pkgs/llvm-ompss2/default.nix { ompss2rt = final.nanos6; };
+    clangOmpss2Nodes = callPackage ./pkgs/llvm-ompss2/default.nix { ompss2rt = final.nodes; openmp = final.openmp; };
+    clangOmpss2NodesOmpv = callPackage ./pkgs/llvm-ompss2/default.nix { ompss2rt = final.nodes; openmp = final.openmpv; };
     clangOmpss2Unwrapped = callPackage ./pkgs/llvm-ompss2/clang.nix { };
     cudainfo = prev.callPackage ./pkgs/cudainfo/default.nix { };
     #extrae = callPackage ./pkgs/extrae/default.nix { }; # Broken and outdated
@@ -56,10 +56,10 @@ let
     #psmpi = callPackage ./pkgs/parastation/psmpi.nix { }; # Unmaintaned
     slurm = import ./pkgs/slurm/default.nix { slurm = prev.slurm; };
     sonar = callPackage ./pkgs/sonar/default.nix { };
-    stdenvClangOmpss2 = final.stdenv.override { cc = final.buildPackages.clangOmpss2; allowedRequisites = null; };
-    stdenvClangOmpss2Nanos6 = final.stdenv.override { cc = final.buildPackages.clangOmpss2Nanos6; allowedRequisites = null; };
-    stdenvClangOmpss2Nodes = final.stdenv.override { cc = final.buildPackages.clangOmpss2Nodes; allowedRequisites = null; };
-    stdenvClangOmpss2NodesOmpv = final.stdenv.override { cc = final.buildPackages.clangOmpss2NodesOmpv; allowedRequisites = null; };
+    stdenvClangOmpss2 = final.stdenv.override { cc = final.clangOmpss2; allowedRequisites = null; };
+    stdenvClangOmpss2Nanos6 = final.stdenv.override { cc = final.clangOmpss2Nanos6; allowedRequisites = null; };
+    stdenvClangOmpss2Nodes = final.stdenv.override { cc = final.clangOmpss2Nodes; allowedRequisites = null; };
+    stdenvClangOmpss2NodesOmpv = final.stdenv.override { cc = final.clangOmpss2NodesOmpv; allowedRequisites = null; };
     tagaspi = callPackage ./pkgs/tagaspi/default.nix { };
     tampi = callPackage ./pkgs/tampi/default.nix { };
     upc-qaire-exporter = prev.callPackage ./pkgs/upc-qaire-exporter/default.nix { };

pkgs/llvm-ompss2/clang.nix

@@ -1,9 +1,9 @@
 {
-  stdenv
-, llvmPackages_latest
+  llvmPackages_latest
 , lib
 , fetchFromGitHub
 , cmake
+, bash
 , python3
 , perl
 , which
@@ -11,6 +11,7 @@
 , libffi
 , zlib
 , pkg-config
+, gcc # needed to set the rpath of libstdc++ for clang-tblgen
 , enableDebug ? false
 , useGit ? false
 , gitUrl ? "ssh://git@bscpm04.bsc.es/llvm-ompss/llvm-mono.git"
@@ -19,10 +20,7 @@
 }:
 
 let
-  llvmPackages = llvmPackages_latest;
-  llvmStdenv = llvmPackages.stdenv;
-  # needed to set the rpath of libstdc++ for clang-tblgen
-  gcc = stdenv.cc;
+  stdenv = llvmPackages_latest.stdenv;
 
   release = rec {
     version = "2025.11";
@@ -45,7 +43,7 @@ let
 
   source = if (useGit) then git else release;
 
-in llvmStdenv.mkDerivation {
+in stdenv.mkDerivation {
   pname = "clang-ompss2";
   inherit (source) src version;
 
@@ -63,12 +61,13 @@ in llvmStdenv.mkDerivation {
   };
 
   nativeBuildInputs = [
+    bash
     cmake
     elfutils
-    llvmPackages.lld
-    perl
+    llvmPackages_latest.lld
     pkg-config
     python3
+    perl
     which
     zlib
   ];
@@ -99,13 +98,8 @@ in llvmStdenv.mkDerivation {
     cd build
     cmakeDir="../llvm"
     cmakeFlagsArray=(
-      "-DLLVM_HOST_TRIPLE=${llvmStdenv.targetPlatform.config}"
-    '' + (if "${llvmStdenv.targetPlatform.config}" == "riscv64-unknown-linux-gnu" then ''
-      "-DLLVM_DEFAULT_TARGET_TRIPLE=riscv64-unknown-linux-gnu"
-      "-DLLVM_TARGETS_TO_BUILD=RISCV"
-    '' else ''
+      "-DLLVM_HOST_TRIPLE=${stdenv.targetPlatform.config}"
       "-DLLVM_TARGETS_TO_BUILD=host"
-    '') + ''
       "-DLLVM_BUILD_LLVM_DYLIB=ON"
       "-DLLVM_LINK_LLVM_DYLIB=ON"
       # Required to run clang-ast-dump and clang-tblgen during build
@@ -114,8 +108,7 @@ in llvmStdenv.mkDerivation {
       "-DCMAKE_CXX_FLAGS_DEBUG=-g -ggnu-pubnames"
       "-DCMAKE_EXE_LINKER_FLAGS_DEBUG=-Wl,--gdb-index"
       "-DLLVM_LIT_ARGS=-sv --xunit-xml-output=xunit.xml"
-      "-DLLVM_ENABLE_PROJECTS=clang;lld"
-      "-DLLVM_ENABLE_RUNTIMES=compiler-rt"
+      "-DLLVM_ENABLE_PROJECTS=clang;compiler-rt;lld"
       "-DLLVM_ENABLE_ASSERTIONS=ON"
       "-DLLVM_INSTALL_TOOLCHAIN_ONLY=ON"
       "-DCMAKE_INSTALL_BINDIR=bin"

pkgs/llvm-ompss2/default.nix

@@ -3,42 +3,25 @@
 , lib
 , gcc
 , clangOmpss2Unwrapped
-
-, openmp
-, useOpenmp  ? false
-, openmpv
-, useOpenmpV ? false
-, nanos6
-, useNanos6 ? false
-, nodes
-, useNodes ? false
-
+, openmp ? null
 , wrapCCWith
 , llvmPackages_latest
+, ompss2rt ? null
 }:
 
 with lib;
 
 let
-  getSplice = target: pkg: if pkg ? "__spliced" && pkg.__spliced ? target then pkg.__spliced."${target}" else pkg;
-  getSpliceTargetTarget = getSplice "targetTarget";
-  omp = if useOpenmp then openmp else if useOpenmpV then openmpv else null;
-  ompss2rtUnspliced = if useNanos6 then nanos6 else if useNodes then nodes else null;
-  ompss2rt = getSpliceTargetTarget ompss2rtUnspliced;
-  usingNodesAndOmpv = omp != null && ompss2rt != null && (omp.pname == "openmp-v" && ompss2rt.pname == "nodes");
-  sameNosvUnspliced = omp != null && ompss2rtUnspliced != null && omp.nosv == ompss2rtUnspliced.nosv;
-  sameNosvSpliced = (getSpliceTargetTarget omp.nosv) == ompss2rt.nosv;
+  usingNodesAndOmpv = (openmp.pname == "openmp-v" && ompss2rt.pname == "nodes");
+  sameNosv = openmp.nosv == ompss2rt.nosv;
 in
 
-assert assertMsg (usingNodesAndOmpv -> sameNosvUnspliced) "OpenMP-V and NODES must share the same nOS-V before splice";
-assert assertMsg (usingNodesAndOmpv -> sameNosvSpliced) "OpenMP-V and NODES must share the same nOS-V after splice";
-assert assertMsg (useOpenmp -> !useOpenmpV) "Either OpenMP or OpenMP-V may be enabled, but not both";
-assert assertMsg (useNanos6 -> !useNodes) "Either Nanos6 or NODES may be enabled, but not both";
+assert assertMsg (usingNodesAndOmpv -> sameNosv) "OpenMP-V and NODES must share the same nOS-V";
 
 let
   homevar = if ompss2rt.pname == "nanos6" then "NANOS6_HOME" else "NODES_HOME";
   rtname  = if ompss2rt.pname == "nanos6" then "libnanos6" else "libnodes";
-  ompname = if omp.pname == "openmp-v" then  "libompv" else "libomp";
+  ompname = if openmp.pname == "openmp-v" then  "libompv" else "libomp";
 
 
   # We need to replace the lld linker from bintools with our linker just built,
@@ -54,10 +37,10 @@ let
   inherit gcc;
   cc = clangOmpss2Unwrapped;
   gccVersion = with versions; let v = gcc.version; in concatStringsSep "." [(major v) (minor v) (patch v)];
-in (wrapCCWith {
+in wrapCCWith {
   inherit cc bintools;
   # extraPackages adds packages to depsTargetTargetPropagated
-  extraPackages = optional (omp != null) omp;
+  extraPackages = optional (openmp != null) openmp;
   extraBuildCommands = ''
     echo "-target ${targetConfig}" >> $out/nix-support/cc-cflags
     echo "-B${gcc.cc}/lib/gcc/${targetConfig}/${gccVersion}" >> $out/nix-support/cc-cflags
@@ -73,15 +56,15 @@ in (wrapCCWith {
 
     echo "--gcc-toolchain=${gcc}" >> $out/nix-support/cc-cflags
 
-    wrap ${targetConfig}clang++  $wrapper $ccPath/clang++
-    wrap ${targetConfig}clang    $wrapper $ccPath/clang
+    wrap clang++  $wrapper $ccPath/clang++
 
-  '' + optionalString (omp != null) ''
+  '' + optionalString (openmp != null) ''
     echo "export OPENMP_RUNTIME=${ompname}" >> $out/nix-support/cc-wrapper-hook
   '' + optionalString (ompss2rt != null) ''
     echo "export OMPSS2_RUNTIME=${rtname}" >> $out/nix-support/cc-wrapper-hook
     echo "export ${homevar}=${ompss2rt}"   >> $out/nix-support/cc-wrapper-hook
   '' + optionalString (ompss2rt != null && ompss2rt.pname == "nodes") ''
-    echo "export NOSV_HOME=${ompss2rt}" >> $out/nix-support/cc-wrapper-hook
+    echo "export NOSV_HOME=${ompss2rt.nosv}" >> $out/nix-support/cc-wrapper-hook
   '';
-}).overrideAttrs (prev: { passthru = (prev.passthru or {}) // { inherit ompss2rt; }; })
+}
+

pkgs/nanos6/check-papi-version-with-pkgconfig.patch

@@ -0,0 +1,67 @@
+diff --git a/m4/papi.m4 b/m4/papi.m4
+--- a/m4/papi.m4
++++ b/m4/papi.m4
+@@ -24,12 +24,13 @@ AC_DEFUN([AC_CHECK_PAPI],
+ 		else
+ 			PKG_CHECK_MODULES(
+ 				[papi],
+-				[papi],
++				[papi >= 5.6.0],
+ 				[
+ 					AC_MSG_CHECKING([the PAPI installation prefix])
+ 					AC_MSG_RESULT([retrieved from pkg-config])
+ 					papi_CPPFLAGS="${papi_CFLAGS}"
+ 					ac_use_papi=yes
++					ac_papi_version_correct=yes
+ 				], [
+ 					AC_MSG_CHECKING([the PAPI installation prefix])
+ 					AC_MSG_RESULT([not available])
+@@ -67,27 +68,29 @@ AC_DEFUN([AC_CHECK_PAPI],
+ 		fi
+ 
+ 		if test x"${ac_use_papi}" = x"yes" ; then
+-			if test x"${ac_cv_use_papi_prefix}" != x"" ; then
+-				papiBinary=${ac_cv_use_papi_prefix}/bin/papi_version
+-			else
+-				papiBinary=papi_version
+-			fi
+-			papiVersion=`$papiBinary | sed 's/[[^0-9.]]*\([[0-9.]]*\).*/\1/'`
++			if test x"${ac_papi_version_correct}" != x"yes" ; then
++				if test x"${ac_cv_use_papi_prefix}" != x"" ; then
++					papiBinary=${ac_cv_use_papi_prefix}/bin/papi_version
++				else
++					papiBinary=papi_version
++				fi
++				papiVersion=`$papiBinary | sed 's/[[^0-9.]]*\([[0-9.]]*\).*/\1/'`
+ 
+-			AX_COMPARE_VERSION(
+-				[[${papiVersion}]],
+-				[[ge]],
+-				[[5.6.0]],
+-				[[ac_papi_version_correct=yes]],
+-				[[ac_papi_version_correct=no]]
+-			)
++				AX_COMPARE_VERSION(
++					[[${papiVersion}]],
++					[[ge]],
++					[[5.6.0]],
++					[[ac_papi_version_correct=yes]],
++					[[ac_papi_version_correct=no]]
++				)
+ 
+-			if test x"${ac_papi_version_correct}" != x"yes" ; then
+-				AC_MSG_ERROR([PAPI version must be >= 5.6.0.])
+-				ac_use_papi=no
+-			else
+-				AC_MSG_CHECKING([if the PAPI version >= 5.6.0.])
+-				AC_MSG_RESULT([${ac_papi_version_correct}])
++				if test x"${ac_papi_version_correct}" != x"yes" ; then
++					AC_MSG_ERROR([PAPI version must be >= 5.6.0.])
++					ac_use_papi=no
++				else
++					AC_MSG_CHECKING([if the PAPI version >= 5.6.0.])
++					AC_MSG_RESULT([${ac_papi_version_correct}])
++				fi
+ 			fi
+ 		fi
+ 

pkgs/nanos6/default.nix

@@ -80,8 +80,7 @@ in
       (optional enableGlibcxxDebug "CXXFLAGS=-D_GLIBCXX_DEBUG") ++
       # Most nanos6 api symbols are resolved at runtime, so prefer
       # ifunc by default
-      (optional isCross "--with-symbol-resolution=ifunc") ++
-      (optional enablePapi "--with-papi=${papi}");
+      (optional isCross "--with-symbol-resolution=ifunc");
 
     postConfigure = lib.optionalString (!enableDebug) ''
       # Disable debug
@@ -97,6 +96,7 @@ in
     separateDebugInfo = true;
 
     strictDeps = true;
+    patches = [ ./check-papi-version-with-pkgconfig.patch ];
 
     nativeBuildInputs = [
       autoconf

pkgs/nosv/check-papi-version-with-pkgconfig.patch

@@ -0,0 +1,68 @@
+diff --git a/m4/papi.m4 b/m4/papi.m4
+index de905848..fa3db9a1 100644
+--- a/m4/papi.m4
++++ b/m4/papi.m4
+@@ -24,12 +24,13 @@ AC_DEFUN([AC_CHECK_PAPI],
+ 		else
+ 			PKG_CHECK_MODULES(
+ 				[papi],
+-				[papi],
++				[papi >= 5.6.0],
+ 				[
+ 					AC_MSG_CHECKING([the PAPI installation prefix])
+ 					AC_MSG_RESULT([retrieved from pkg-config])
+ 					papi_CFLAGS="${papi_CFLAGS}"
+ 					ac_use_papi=yes
++					ac_papi_version_correct=yes
+ 				], [
+ 					AC_MSG_CHECKING([the PAPI installation prefix])
+ 					AC_MSG_RESULT([not available])
+@@ -67,27 +68,29 @@ AC_DEFUN([AC_CHECK_PAPI],
+ 		fi
+ 
+ 		if test x"${ac_use_papi}" = x"yes" ; then
+-			if test x"${ac_cv_use_papi_prefix}" != x"" ; then
+-				papiBinary=${ac_cv_use_papi_prefix}/bin/papi_version
+-			else
+-				papiBinary=papi_version
+-			fi
+-			papiVersion=`$papiBinary | sed 's/[[^0-9.]]*\([[0-9.]]*\).*/\1/'`
++			if test x"${ac_papi_version_correct}" != x"yes" ; then
++				if test x"${ac_cv_use_papi_prefix}" != x"" ; then
++					papiBinary=${ac_cv_use_papi_prefix}/bin/papi_version
++				else
++					papiBinary=papi_version
++				fi
++				papiVersion=`$papiBinary | sed 's/[[^0-9.]]*\([[0-9.]]*\).*/\1/'`
+ 
+-			AX_COMPARE_VERSION(
+-				[[${papiVersion}]],
+-				[[ge]],
+-				[[5.6.0]],
+-				[[ac_papi_version_correct=yes]],
+-				[[ac_papi_version_correct=no]]
+-			)
++				AX_COMPARE_VERSION(
++					[[${papiVersion}]],
++					[[ge]],
++					[[5.6.0]],
++					[[ac_papi_version_correct=yes]],
++					[[ac_papi_version_correct=no]]
++				)
+ 
+-			if test x"${ac_papi_version_correct}" != x"yes" ; then
+-				AC_MSG_ERROR([PAPI version must be >= 5.6.0.])
+-				ac_use_papi=no
+-			else
+-				AC_MSG_CHECKING([if the PAPI version >= 5.6.0.])
+-				AC_MSG_RESULT([${ac_papi_version_correct}])
++				if test x"${ac_papi_version_correct}" != x"yes" ; then
++					AC_MSG_ERROR([PAPI version must be >= 5.6.0.])
++					ac_use_papi=no
++				else
++					AC_MSG_CHECKING([if the PAPI version >= 5.6.0.])
++					AC_MSG_RESULT([${ac_papi_version_correct}])
++				fi
+ 			fi
+ 		fi
+ 

pkgs/nosv/default.nix

@@ -47,10 +47,11 @@ in
     dontStrip = true;
     separateDebugInfo = true;
     strictDeps = true;
+    patches = [ ./check-papi-version-with-pkgconfig.patch ];
     configureFlags = [
       "--with-ovni=${ovni}"
       "CACHELINE_WIDTH=${toString cacheline}"
-    ] ++ lib.optionals enablePapi [ "--with-papi=${papi}" ];
+    ];
     nativeBuildInputs = [
       autoreconfHook
       pkg-config
@@ -60,7 +61,6 @@ in
       hwloc
       ovni
     ] ++ lib.optionals enablePapi [ papi ];
-    patches = [ ./fix-papi.patch ];
 
     meta = {
       homepage = "https://gitlab.bsc.es/nos-v/nos-v";

pkgs/nosv/fix-papi.patch

@@ -1,136 +0,0 @@
-Commit ID: c09633f172ce4075e0a05a33f6dcbe8e03e1202a
-Change ID: onmwypnnrysktutwsvotqovzponvwrxs
-Bookmarks: fix/papi fix/papi@git fix/papi@origin
-Author   : Aleix Boné <aleix.boneribo@bsc.es> (2025-12-10 11:14:14)
-Committer: Aleix Boné <aleix.boneribo@bsc.es> (2025-12-12 12:56:48)
-
-    Improve PAPI m4 module for cross compilation
-
-diff --git a/m4/papi.m4 b/m4/papi.m4
-index de90584870..8398f856f5 100644
---- a/m4/papi.m4
-+++ b/m4/papi.m4
-@@ -1,6 +1,6 @@
- #	This file is part of Nanos6 and is licensed under the terms contained in the COPYING file.
- #
--#	Copyright (C) 2021-2022 Barcelona Supercomputing Center (BSC)
-+#	Copyright (C) 2021-2025 Barcelona Supercomputing Center (BSC)
- 
- AC_DEFUN([AC_CHECK_PAPI],
- 	[
-@@ -8,34 +8,38 @@
- 			[papi],
- 			[AS_HELP_STRING([--with-papi=prefix], [specify the installation prefix of PAPI])],
- 			[ ac_cv_use_papi_prefix=$withval ],
--			[ ac_cv_use_papi_prefix="" ]
-+			[ ac_cv_use_papi_prefix="check" ]
- 		)
- 
- 		if test x"${ac_cv_use_papi_prefix}" = x"no"; then
- 			AC_MSG_CHECKING([the PAPI installation prefix])
- 			AC_MSG_RESULT([${ac_cv_use_papi_prefix}])
- 			ac_use_papi=no
--		elif test x"${ac_cv_use_papi_prefix}" != x"" ; then
--			AC_MSG_CHECKING([the PAPI installation prefix])
--			AC_MSG_RESULT([${ac_cv_use_papi_prefix}])
--			papi_LIBS="-L${ac_cv_use_papi_prefix}/lib -lpapi -Wl,-rpath,${ac_cv_use_papi_prefix}/lib"
--			papi_CFLAGS="-I$ac_cv_use_papi_prefix/include"
--			ac_use_papi=yes
--		else
-+		elif test x"${ac_cv_use_papi_prefix}" = x""; then
-+			AC_MSG_RESULT([invalid prefix])
-+			AC_MSG_ERROR([papi prefix specified but empty])
-+		elif test x"${ac_cv_use_papi_prefix}" = x"yes" -o x"${ac_cv_use_papi_prefix}" = x"check"; then
- 			PKG_CHECK_MODULES(
- 				[papi],
--				[papi],
-+				[papi >= 5.6.0],
- 				[
- 					AC_MSG_CHECKING([the PAPI installation prefix])
- 					AC_MSG_RESULT([retrieved from pkg-config])
- 					papi_CFLAGS="${papi_CFLAGS}"
- 					ac_use_papi=yes
-+					ac_papi_version_correct=yes
- 				], [
- 					AC_MSG_CHECKING([the PAPI installation prefix])
- 					AC_MSG_RESULT([not available])
- 					ac_use_papi=no
- 				]
- 			)
-+		else
-+			AC_MSG_CHECKING([the PAPI installation prefix])
-+			AC_MSG_RESULT([${ac_cv_use_papi_prefix}])
-+			papi_LIBS="-L${ac_cv_use_papi_prefix}/lib -lpapi -Wl,-rpath,${ac_cv_use_papi_prefix}/lib"
-+			papi_CFLAGS="-I$ac_cv_use_papi_prefix/include"
-+			ac_use_papi=yes
- 		fi
- 
- 		if test x"${ac_use_papi}" = x"yes" ; then
-@@ -53,10 +57,10 @@
- 					ac_use_papi=yes
- 				],
- 				[
--					if test x"${ac_cv_use_papi_prefix}" != x"" ; then
--						AC_MSG_ERROR([PAPI cannot be found.])
-+					if test x"${ac_cv_use_papi_prefix}" = x"yes" ; then
-+						AC_MSG_ERROR([PAPI >= 5.6.0 cannot be found.])
- 					else
--						AC_MSG_WARN([PAPI cannot be found.])
-+						AC_MSG_WARN([PAPI >= 5.6.0 not available.])
- 					fi
- 					ac_use_papi=no
- 				]
-@@ -64,30 +68,38 @@
- 
- 			CFLAGS="${ac_save_CFLAGS}"
- 			LIBS="${ac_save_LIBS}"
-+		elif test x"${ac_cv_use_papi_prefix}" = x"yes" ; then
-+			AC_MSG_ERROR([PAPI >= 5.6.0 cannot be found.])
- 		fi
- 
--		if test x"${ac_use_papi}" = x"yes" ; then
--			if test x"${ac_cv_use_papi_prefix}" != x"" ; then
-+		if test x"${ac_use_papi}" = x"yes" -a x"${ac_papi_version_correct}" != x"yes" ; then
-+			if test x"${ac_cv_use_papi_prefix}" != x"yes" -a x"${ac_cv_use_papi_prefix}" != x"check" ; then
- 				papiBinary=${ac_cv_use_papi_prefix}/bin/papi_version
- 			else
- 				papiBinary=papi_version
- 			fi
--			papiVersion=`$papiBinary | sed 's/[[^0-9.]]*\([[0-9.]]*\).*/\1/'`
- 
--			AX_COMPARE_VERSION(
--				[[${papiVersion}]],
--				[[ge]],
--				[[5.6.0]],
--				[[ac_papi_version_correct=yes]],
--				[[ac_papi_version_correct=no]]
--			)
- 
--			if test x"${ac_papi_version_correct}" != x"yes" ; then
--				AC_MSG_ERROR([PAPI version must be >= 5.6.0.])
--				ac_use_papi=no
-+			if test x"$cross_compiling" = x"yes" ; then
-+				AC_MSG_WARN([Cross-compiling detected, skipping PAPI version check])
- 			else
--				AC_MSG_CHECKING([if the PAPI version >= 5.6.0.])
--				AC_MSG_RESULT([${ac_papi_version_correct}])
-+				papiVersion=`$papiBinary | sed 's/[[^0-9.]]*\([[0-9.]]*\).*/\1/'`
-+
-+				AX_COMPARE_VERSION(
-+					[[${papiVersion}]],
-+					[[ge]],
-+					[[5.6.0]],
-+					[[ac_papi_version_correct=yes]],
-+					[[ac_papi_version_correct=no]]
-+				)
-+
-+				if test x"${ac_papi_version_correct}" != x"yes" ; then
-+					AC_MSG_ERROR([PAPI version must be >= 5.6.0.])
-+					ac_use_papi=no
-+				else
-+					AC_MSG_CHECKING([if the PAPI version >= 5.6.0.])
-+					AC_MSG_RESULT([${ac_papi_version_correct}])
-+				fi
- 			fi
- 		fi
-