diff --git a/lib/systems/doubles.nix b/lib/systems/doubles.nix
index c6d90ba9850d..61ba7dad7cc7 100644
--- a/lib/systems/doubles.nix
+++ b/lib/systems/doubles.nix
@@ -96,5 +96,5 @@ in {
 
   embedded      = filterDoubles predicates.isNone;
 
-  mesaPlatforms = ["i686-linux" "x86_64-linux" "x86_64-darwin" "armv5tel-linux" "armv6l-linux" "armv7l-linux" "armv7a-linux" "aarch64-linux" "powerpc64-linux" "powerpc64le-linux" "aarch64-darwin"];
+  mesaPlatforms = ["i686-linux" "x86_64-linux" "x86_64-darwin" "armv5tel-linux" "armv6l-linux" "armv7l-linux" "armv7a-linux" "aarch64-linux" "powerpc64-linux" "powerpc64le-linux" "aarch64-darwin" "riscv64-linux"];
 }
diff --git a/pkgs/applications/networking/mailreaders/claws-mail/default.nix b/pkgs/applications/networking/mailreaders/claws-mail/default.nix
index 4a13cf68a882..e28680c245fb 100644
--- a/pkgs/applications/networking/mailreaders/claws-mail/default.nix
+++ b/pkgs/applications/networking/mailreaders/claws-mail/default.nix
@@ -21,7 +21,7 @@
 , enableLdap ? true, openldap
 , enableNetworkManager ? true, networkmanager
 , enableLibetpan ? true, libetpan
-, enableValgrind ? true, valgrind
+, enableValgrind ? !stdenv.isDarwin && lib.meta.availableOn stdenv.hostPlatform valgrind, valgrind
 , enableSvg ? true, librsvg
 
 # Configure claws-mail's plugins
diff --git a/pkgs/development/interpreters/php/generic.nix b/pkgs/development/interpreters/php/generic.nix
index 558fa45a1fd9..d64349eaa937 100644
--- a/pkgs/development/interpreters/php/generic.nix
+++ b/pkgs/development/interpreters/php/generic.nix
@@ -28,7 +28,7 @@ let
     , embedSupport ? false
     , ipv6Support ? true
     , systemdSupport ? stdenv.isLinux
-    , valgrindSupport ? !stdenv.isDarwin
+    , valgrindSupport ? !stdenv.isDarwin && lib.meta.availableOn stdenv.hostPlatform valgrind
     , ztsSupport ? apxs2Support
     }@args:
 
diff --git a/pkgs/development/libraries/libpsl/default.nix b/pkgs/development/libraries/libpsl/default.nix
index e68219f63485..85afe93ea7a7 100644
--- a/pkgs/development/libraries/libpsl/default.nix
+++ b/pkgs/development/libraries/libpsl/default.nix
@@ -14,7 +14,9 @@
 , publicsuffix-list
 }:
 
-stdenv.mkDerivation rec {
+let
+  enableValgrindTests = !stdenv.isDarwin && lib.meta.availableOn stdenv.hostPlatform valgrind;
+in stdenv.mkDerivation rec {
   pname = "libpsl";
   version = "0.21.0";
 
@@ -32,7 +34,7 @@ stdenv.mkDerivation rec {
     pkg-config
     python3
     libxslt
-  ] ++ lib.optionals (!stdenv.isDarwin) [
+  ] ++ lib.optionals enableValgrindTests [
     valgrind
   ];
 
@@ -60,7 +62,7 @@ stdenv.mkDerivation rec {
     "--with-psl-distfile=${publicsuffix-list}/share/publicsuffix/public_suffix_list.dat"
     "--with-psl-file=${publicsuffix-list}/share/publicsuffix/public_suffix_list.dat"
     "--with-psl-testfile=${publicsuffix-list}/share/publicsuffix/test_psl.txt"
-  ] ++ lib.optionals (!stdenv.isDarwin) [
+  ] ++ lib.optionals enableValgrindTests [
     "--enable-valgrind-tests"
   ];
 
diff --git a/pkgs/development/libraries/mesa/default.nix b/pkgs/development/libraries/mesa/default.nix
index 3c7ea16b26ae..0e24d27b0d79 100644
--- a/pkgs/development/libraries/mesa/default.nix
+++ b/pkgs/development/libraries/mesa/default.nix
@@ -10,7 +10,7 @@
 , vulkanDrivers ? ["auto"]
 , eglPlatforms ? [ "x11" ] ++ lib.optionals stdenv.isLinux [ "wayland" ]
 , OpenGL, Xplugin
-, withValgrind ? stdenv.hostPlatform.isLinux && !stdenv.hostPlatform.isAarch32, valgrind-light
+, withValgrind ? !stdenv.isDarwin && lib.meta.availableOn stdenv.hostPlatform valgrind-light, valgrind-light
 , enableGalliumNine ? stdenv.isLinux
 , enableOSMesa ? stdenv.isLinux
 }:
@@ -64,6 +64,11 @@ self = stdenv.mkDerivation {
       url = "https://gitlab.freedesktop.org/mesa/mesa/commit/aebbf819df6d1e.patch";
       sha256 = "17248hyzg43d73c86p077m4lv1pkncaycr3l27hwv9k4ija9zl8q";
     })
+    (fetchpatch {
+      name = "add-riscv-default-selections.patch";
+      url = "https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11346.patch";
+      sha256 = "1nwqslr1g6m83i0r40710havkyf03yxkgaiwgxz2zlw2xkbrnzw0";
+    })
   ] ++ optionals (stdenv.isDarwin && stdenv.isAarch64) [
     # Fix aarch64-darwin build, remove when upstreaam supports it out of the box.
     # See: https://gitlab.freedesktop.org/mesa/mesa/-/issues/1020
diff --git a/pkgs/top-level/php-packages.nix b/pkgs/top-level/php-packages.nix
index 5575c1d429cf..744e40c95dd2 100644
--- a/pkgs/top-level/php-packages.nix
+++ b/pkgs/top-level/php-packages.nix
@@ -364,7 +364,7 @@ lib.makeScope pkgs.newScope (self: with self; {
       # oci8 (7.4, 7.3, 7.2)
       # odbc (7.4, 7.3, 7.2)
       { name = "opcache";
-        buildInputs = [ pcre2 ] ++ lib.optionals (!stdenv.isDarwin && lib.versionAtLeast php.version "8.0") [
+        buildInputs = [ pcre2 ] ++ lib.optionals (lib.versionAtLeast php.version "8.0" && !stdenv.isDarwin && lib.meta.availableOn stdenv.hostPlatform valgrind) [
           valgrind.dev
         ];
         patches = lib.optionals (lib.versionOlder php.version "7.4") [