Passing Hash values is using the values of an Hash declared outside a function, to be used inside the function to make changes in that hash, then to return the modified values as required. If you are passing variables to a function there is an array @_ which list all the variables when the function is called.

   #! C:\programfiles\perl\bin\perl
   print "content-type: text/html\n\n";
   %name = ('Tom',26,'Peter',51,'Jones',23,'John',43);
   hash1( \%name);
   sub hash1
   {
    my ($element) = @_;
    foreach $key(sort{$$element{$b}<=>$$element{$a}}keys %$element) 
    {
    $tmp=$key."=>".$$element{$key}."<br>";
    print $tmp;
    }
    }

    Peter=>51
    John=>43
    Tom=>26
    Jones=>23

In the above example the hash "%name" is sorted inside the function "hash1", its sorted element by element then the sorted values are returned to hash indeed.