diff --git a/lib/systems/platforms.nix b/lib/systems/platforms.nix
index e230888d9fcb..b80ed1efc8e8 100644
--- a/lib/systems/platforms.nix
+++ b/lib/systems/platforms.nix
@@ -632,6 +632,15 @@ rec {
     else if platform.isPower64 then
       if platform.isLittleEndian then powernv else ppc64
 
+    else if platform.isSh4 then
+      {
+        linux-kernel = {
+          target = "vmlinux";
+          # SH arch doesn't have a 'make install' target.
+          installTarget = "vmlinux";
+        };
+      }
+
     else
       { };
 }
diff --git a/pkgs/development/compilers/gcc/common/builder.nix b/pkgs/development/compilers/gcc/common/builder.nix
index 1e90828a6643..edd28a26ce95 100644
--- a/pkgs/development/compilers/gcc/common/builder.nix
+++ b/pkgs/development/compilers/gcc/common/builder.nix
@@ -278,106 +278,117 @@ originalAttrs:
           makeCompatibilitySymlink lib $targetConfig/lib64
         '';
 
-    postInstall = ''
-      # Clean up our compatibility symlinks (see above)
-      for link in "''${compatibilitySymlinks[@]}"; do
-        echo "Removing compatibility symlink: $link"
-        rm -f "$link"
-      done
-
-      # Move target runtime libraries to lib output.
-      # For non-cross, they're in $out/lib; for cross, they're in $out/$targetConfig/lib.
-      targetLibDir="''${targetConfig+$targetConfig/}lib"
-
-      moveToOutput "$targetLibDir/lib*.so*" "''${!outputLib}"
-      moveToOutput "$targetLibDir/lib*.dylib" "''${!outputLib}"
-      moveToOutput "$targetLibDir/lib*.dll.a" "''${!outputLib}"
-      moveToOutput "$targetLibDir/lib*.dll" "''${!outputLib}"
-      moveToOutput "share/gcc-*/python" "''${!outputLib}"
-
-      if [ -z "$enableShared" ]; then
-          moveToOutput "$targetLibDir/lib*.a" "''${!outputLib}"
-      fi
-
-      for i in "''${!outputLib}"/$targetLibDir/*.py; do
-          substituteInPlace "$i" --replace "$out" "''${!outputLib}"
-      done
-
-      # Multilib and cross can't exist at the same time, so just use lib64 here
-      if [ -n "$enableMultilib" ]; then
-          moveToOutput "lib64/lib*.so*" "''${!outputLib}"
-          moveToOutput "lib64/lib*.dylib" "''${!outputLib}"
-          moveToOutput "lib64/lib*.dll.a" "''${!outputLib}"
-          moveToOutput "lib64/lib*.dll" "''${!outputLib}"
-
-          for i in "''${!outputLib}"/lib64/*.py; do
-              substituteInPlace "$i" --replace "$out" "''${!outputLib}"
-          done
-      fi
-
-      # Remove `fixincl' to prevent a retained dependency on the
-      # previous gcc.
-      rm -rf $out/libexec/gcc/*/*/install-tools
-      rm -rf $out/lib/gcc/*/*/install-tools
-
-      # More dependencies with the previous gcc or some libs (gccbug stores the build command line)
-      rm -rf $out/bin/gccbug
-
-      # Remove .la files, they're not adjusted for the makeCompatibilitySymlink magic,
-      # which confuses libtool and leads to weird linking errors.
-      # Removing the files just makes libtool link .so files directly, which is usually
-      # what we want anyway.
-      find $out -name '*.la' -delete
-
-      if type "install_name_tool"; then
-          for i in "''${!outputLib}"/lib/*.*.dylib "''${!outputLib}"/lib/*.so.[0-9]; do
-              install_name_tool -id "$i" "$i" || true
-              for old_path in $(otool -L "$i" | grep "$out" | awk '{print $1}'); do
-                new_path=`echo "$old_path" | sed "s,$out,''${!outputLib},"`
-                install_name_tool -change "$old_path" "$new_path" "$i" || true
-              done
-          done
-      fi
-
-      # Get rid of some "fixed" header files
-      rm -rfv $out/lib/gcc/*/*/include-fixed/{root,linux,sys/mount.h,bits/statx.h,pthread.h}
-
-      # Replace hard links for i686-pc-linux-gnu-gcc etc. with symlinks.
-      for i in $out/bin/*-gcc*; do
-          if cmp -s $out/bin/gcc $i; then
-              ln -sfn gcc $i
+    postInstall =
+      # SH installs libraries into a multilib subdirectory (e.g. lib/!m4/)
+      # even with --disable-multilib; move them to the expected location.
+      lib.optionalString stdenv.targetPlatform.isSh4 ''
+        for _mdir in $out/''${targetConfig+$targetConfig/}lib/!*/; do
+          if [ -d "$_mdir" ]; then
+            mv "$_mdir"/* $out/''${targetConfig+$targetConfig/}lib/
+            rmdir "$_mdir"
           fi
-      done
+        done
+      ''
+      + ''
+        # Clean up our compatibility symlinks (see above)
+        for link in "''${compatibilitySymlinks[@]}"; do
+          echo "Removing compatibility symlink: $link"
+          rm -f "$link"
+        done
 
-      for i in $out/bin/c++ $out/bin/*-c++* $out/bin/*-g++*; do
-          if cmp -s $out/bin/g++ $i; then
-              ln -sfn g++ $i
-          fi
-      done
+        # Move target runtime libraries to lib output.
+        # For non-cross, they're in $out/lib; for cross, they're in $out/$targetConfig/lib.
+        targetLibDir="''${targetConfig+$targetConfig/}lib"
 
-      # Two identical man pages are shipped (moving and compressing is done later)
-      for i in "$out"/share/man/man1/*g++.1; do
-          if test -e "$i"; then
-              man_prefix=`echo "$i" | sed "s,.*/\(.*\)g++.1,\1,"`
-              ln -sf "$man_prefix"gcc.1 "$i"
-          fi
-      done
-    ''
-    + lib.optionalString stdenv.targetPlatform.isCygwin ''
-      targetBinDir="''${targetConfig+$targetConfig/}bin"
-      for i in "''${!outputBin}/$targetLibDir"/cyg*.dll; do
-        mkdir -p "''${!outputLib}/$targetBinDir"
-        mv "$i" "''${!outputLib}/$targetBinDir"/
-      done
-    ''
-    # if cross-compiling, link from $lib/lib to $lib/${targetConfig}.
-    # since native-compiles have $lib/lib as a directory (not a
-    # symlink), this ensures that in every case we can assume that
-    # $lib/lib contains the .so files
-    + lib.optionalString isCross ''
-      if [ -e "$lib/$targetConfig/lib" ]; then
-        ln -s "$lib/$targetConfig/lib" "$lib/lib"
-      fi
-    '';
+        moveToOutput "$targetLibDir/lib*.so*" "''${!outputLib}"
+        moveToOutput "$targetLibDir/lib*.dylib" "''${!outputLib}"
+        moveToOutput "$targetLibDir/lib*.dll.a" "''${!outputLib}"
+        moveToOutput "$targetLibDir/lib*.dll" "''${!outputLib}"
+        moveToOutput "share/gcc-*/python" "''${!outputLib}"
+
+        if [ -z "$enableShared" ]; then
+            moveToOutput "$targetLibDir/lib*.a" "''${!outputLib}"
+        fi
+
+        for i in "''${!outputLib}"/$targetLibDir/*.py; do
+            substituteInPlace "$i" --replace "$out" "''${!outputLib}"
+        done
+
+        # Multilib and cross can't exist at the same time, so just use lib64 here
+        if [ -n "$enableMultilib" ]; then
+            moveToOutput "lib64/lib*.so*" "''${!outputLib}"
+            moveToOutput "lib64/lib*.dylib" "''${!outputLib}"
+            moveToOutput "lib64/lib*.dll.a" "''${!outputLib}"
+            moveToOutput "lib64/lib*.dll" "''${!outputLib}"
+
+            for i in "''${!outputLib}"/lib64/*.py; do
+                substituteInPlace "$i" --replace "$out" "''${!outputLib}"
+            done
+        fi
+
+        # Remove `fixincl' to prevent a retained dependency on the
+        # previous gcc.
+        rm -rf $out/libexec/gcc/*/*/install-tools
+        rm -rf $out/lib/gcc/*/*/install-tools
+
+        # More dependencies with the previous gcc or some libs (gccbug stores the build command line)
+        rm -rf $out/bin/gccbug
+
+        # Remove .la files, they're not adjusted for the makeCompatibilitySymlink magic,
+        # which confuses libtool and leads to weird linking errors.
+        # Removing the files just makes libtool link .so files directly, which is usually
+        # what we want anyway.
+        find $out -name '*.la' -delete
+
+        if type "install_name_tool"; then
+            for i in "''${!outputLib}"/lib/*.*.dylib "''${!outputLib}"/lib/*.so.[0-9]; do
+                install_name_tool -id "$i" "$i" || true
+                for old_path in $(otool -L "$i" | grep "$out" | awk '{print $1}'); do
+                  new_path=`echo "$old_path" | sed "s,$out,''${!outputLib},"`
+                  install_name_tool -change "$old_path" "$new_path" "$i" || true
+                done
+            done
+        fi
+
+        # Get rid of some "fixed" header files
+        rm -rfv $out/lib/gcc/*/*/include-fixed/{root,linux,sys/mount.h,bits/statx.h,pthread.h}
+
+        # Replace hard links for i686-pc-linux-gnu-gcc etc. with symlinks.
+        for i in $out/bin/*-gcc*; do
+            if cmp -s $out/bin/gcc $i; then
+                ln -sfn gcc $i
+            fi
+        done
+
+        for i in $out/bin/c++ $out/bin/*-c++* $out/bin/*-g++*; do
+            if cmp -s $out/bin/g++ $i; then
+                ln -sfn g++ $i
+            fi
+        done
+
+        # Two identical man pages are shipped (moving and compressing is done later)
+        for i in "$out"/share/man/man1/*g++.1; do
+            if test -e "$i"; then
+                man_prefix=`echo "$i" | sed "s,.*/\(.*\)g++.1,\1,"`
+                ln -sf "$man_prefix"gcc.1 "$i"
+            fi
+        done
+      ''
+      + lib.optionalString stdenv.targetPlatform.isCygwin ''
+        targetBinDir="''${targetConfig+$targetConfig/}bin"
+        for i in "''${!outputBin}/$targetLibDir"/cyg*.dll; do
+          mkdir -p "''${!outputLib}/$targetBinDir"
+          mv "$i" "''${!outputLib}/$targetBinDir"/
+        done
+      ''
+      # if cross-compiling, link from $lib/lib to $lib/${targetConfig}.
+      # since native-compiles have $lib/lib as a directory (not a
+      # symlink), this ensures that in every case we can assume that
+      # $lib/lib contains the .so files
+      + lib.optionalString isCross ''
+        if [ -e "$lib/$targetConfig/lib" ]; then
+          ln -s "$lib/$targetConfig/lib" "$lib/lib"
+        fi
+      '';
   }
 ))
diff --git a/pkgs/development/compilers/gcc/common/configure-flags.nix b/pkgs/development/compilers/gcc/common/configure-flags.nix
index 98da0be6322e..e2c735c0751f 100644
--- a/pkgs/development/compilers/gcc/common/configure-flags.nix
+++ b/pkgs/development/compilers/gcc/common/configure-flags.nix
@@ -227,6 +227,9 @@ let
         ]
       else
         [ "--disable-multilib" ]
+        # SH targets need m4 and m4-nofpu variants (the kernel uses -m4-nofpu).
+        # An empty list disables -m4-nofpu entirely.
+        ++ lib.optional targetPlatform.isSh4 "--with-multilib-list=m4,m4-nofpu"
     )
     ++ lib.optional (!enableShared) "--disable-shared"
     ++ lib.singleton (lib.enableFeature enablePlugin "plugin")
diff --git a/pkgs/development/libraries/gcc/libgcc/default.nix b/pkgs/development/libraries/gcc/libgcc/default.nix
index 022b766d9097..6895f555ddc7 100644
--- a/pkgs/development/libraries/gcc/libgcc/default.nix
+++ b/pkgs/development/libraries/gcc/libgcc/default.nix
@@ -94,7 +94,7 @@ stdenv.mkDerivation (finalAttrs: {
         options.h \
         insn-constants.h \
   ''
-  + lib.optionalString stdenv.targetPlatform.isM68k ''
+  + lib.optionalString (stdenv.targetPlatform.isM68k || stdenv.targetPlatform.isSh4) ''
     sysroot-suffix.h \
   ''
   + lib.optionalString stdenv.targetPlatform.isAarch32 ''