Fix nanos6 cross-compilation for riscv

Even if we do an override to papi get the proper configure flags for
cross-compiling, the memory fences are not defined for risc-v:

mb.h:67:2: error: #error Need to define rmb for this architecture!

m/common/base.nix

@@ -11,6 +11,7 @@
     ./base/hw.nix
     ./base/net.nix
     ./base/nix.nix
+    ./base/sys-devices.nix
     ./base/ntp.nix
     ./base/rev.nix
     ./base/ssh.nix

m/common/base/sys-devices.nix

@@ -0,0 +1,9 @@
+{
+  nix.settings.system-features = [ "sys-devices" ];
+
+  programs.nix-required-mounts.enable = true;
+  programs.nix-required-mounts.allowedPatterns.sys-devices.paths = [
+    "/sys/devices/system/cpu"
+    "/sys/devices/system/node"
+  ];
+}

overlay.nix

@@ -62,7 +62,7 @@ let
   };
 
   tests = rec {
-    #hwloc = callPackage ./test/bugs/hwloc.nix { }; # Broken, no /sys
+    hwloc = callPackage ./test/bugs/hwloc.nix { };
     #sigsegv = callPackage ./test/reproducers/sigsegv.nix { };
     hello-c = callPackage ./test/compilers/hello-c.nix { };
     hello-cpp = callPackage ./test/compilers/hello-cpp.nix { };

pkgs/lmbench/default.nix

@@ -22,11 +22,7 @@ stdenv.mkDerivation rec {
   '';
 
   buildInputs = [ libtirpc ];
-  patches = [
-    ./fix-install.patch
-    ./gcc-14.patch
-    ./fix-cross.patch
-  ];
+  patches = [ ./fix-install.patch ./gcc-14.patch ];
 
   hardeningDisable = [ "all" ];
 
@@ -39,8 +35,8 @@ stdenv.mkDerivation rec {
       CFLAGS=-Wno-implicit-int
       CPPFLAGS=-I${libtirpc.dev}/include/tirpc
       LDFLAGS=-ltirpc
-      CC=${stdenv.cc.targetPrefix}cc
-      AR=${stdenv.cc.targetPrefix}ar
+      CC=$CC
+      AR=$AR
     )
   '';
 

pkgs/lmbench/fix-cross.patch

@@ -1,13 +0,0 @@
-diff --git a/src/Makefile b/src/Makefile
-index 2555014..356eeb3 100644
---- a/src/Makefile
-+++ b/src/Makefile
-@@ -36,7 +36,7 @@ SHELL=/bin/sh
- 
- CC=`../scripts/compiler`
- MAKE=`../scripts/make`
--AR=ar
-+AR?=ar
- ARCREATE=cr
- 
- # base of installation location

pkgs/nanos6/default.nix

@@ -78,6 +78,8 @@ in
     ] ++
       (optional enableJemalloc "--with-jemalloc=${jemallocNanos6}") ++
       (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");
 
     postConfigure = lib.optionalString (!enableDebug) ''

test/bugs/hwloc.nix

@@ -6,6 +6,7 @@
 
 stdenv.mkDerivation {
   name = "hwloc-test";
+  requiredSystemFeatures = [ "sys-devices" ];
 
   src = ./.;
 
@@ -14,7 +15,7 @@ stdenv.mkDerivation {
   buildPhase = ''
     ls -l /sys
     gcc -lhwloc hwloc.c -o hwloc
-    strace ./hwloc
+    strace ./hwloc > $out
   '';
 
 }

test/compilers/clang-openmp-ld.nix

@@ -23,9 +23,8 @@ in stdenv.mkDerivation {
   dontUnpack = true;
   dontConfigure = true;
 
-  # nOS-V requires access to /sys/devices to request NUMA information. It will
-  # fail to run otherwise, so we disable the sandbox for this test.
-  __noChroot = true;
+  # nOS-V requires access to /sys/devices to request NUMA information
+  requiredSystemFeatures = [ "sys-devices" ];
 
   buildInputs = [ openmp ];
 

test/compilers/clang-openmp-nosv.nix

@@ -36,9 +36,8 @@ in stdenv.mkDerivation {
   dontUnpack = true;
   dontConfigure = true;
 
-  # nOS-V requires access to /sys/devices to request NUMA information. It will
-  # fail to run otherwise, so we disable the sandbox for this test.
-  __noChroot = true;
+  # nOS-V requires access to /sys/devices to request NUMA information
+  requiredSystemFeatures = [ "sys-devices" ];
 
   buildInputs = [ nosv ];
 

test/compilers/clang-openmp.nix

@@ -24,9 +24,8 @@ in stdenv.mkDerivation {
   dontUnpack = true;
   dontConfigure = true;
 
-  # nOS-V requires access to /sys/devices to request NUMA information. It will
-  # fail to run otherwise, so we disable the sandbox for this test.
-  __noChroot = true;
+  # nOS-V requires access to /sys/devices to request NUMA information
+  requiredSystemFeatures = [ "sys-devices" ];
 
   buildPhase = ''
     set -x

test/compilers/ompss2.nix

@@ -25,9 +25,10 @@ stdenv.mkDerivation rec {
   hardeningDisable = [ "all" ];
   #NIX_DEBUG = 1;
   buildInputs = [ ]; #strace gdb;
-  # NODES requires access to /sys/devices to request NUMA information. It will
-  # fail to run otherwise, so we disable the sandbox for this test.
-  __noChroot = true;
+
+  # NODES requires access to /sys/devices to request NUMA information
+  requiredSystemFeatures = [ "sys-devices" ];
+
   buildPhase = ''
     set -x
     #$CC -v