diff -rupN linux-2.4.33-pre1/arch/i386/config.in linux-2.4.33-pre1.i386-emu-rdtsc/arch/i386/config.in
--- linux-2.4.33-pre1/arch/i386/config.in	2004-11-17 18:36:41.000000000 +0100
+++ linux-2.4.33-pre1.i386-emu-rdtsc/arch/i386/config.in	2005-12-29 21:55:00.000000000 +0100
@@ -222,6 +222,10 @@ if [ "$CONFIG_HIGHMEM" = "y" ]; then
    bool 'HIGHMEM I/O support' CONFIG_HIGHIO
 fi
 
+if [ "$CONFIG_X86_HAS_TSC" != "y" ]; then
+   bool "Kernel emulation of user-space RDTSC instructions" CONFIG_X86_EMU_RDTSC
+fi
+
 bool 'Math emulation' CONFIG_MATH_EMULATION
 bool 'MTRR (Memory Type Range Register) support' CONFIG_MTRR
 bool 'Symmetric multi-processing support' CONFIG_SMP
diff -rupN linux-2.4.33-pre1/arch/i386/kernel/irq.c linux-2.4.33-pre1.i386-emu-rdtsc/arch/i386/kernel/irq.c
--- linux-2.4.33-pre1/arch/i386/kernel/irq.c	2003-11-29 00:28:10.000000000 +0100
+++ linux-2.4.33-pre1.i386-emu-rdtsc/arch/i386/kernel/irq.c	2005-12-29 21:55:00.000000000 +0100
@@ -179,6 +179,12 @@ int show_interrupts(struct seq_file *p, 
 	seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
 #endif
 #endif
+#ifdef CONFIG_X86_EMU_RDTSC
+	{
+		extern unsigned int invalid_op_counter;
+		seq_printf(p, "ILL: %10u\n", invalid_op_counter);
+	}
+#endif
 
 	return 0;
 }
diff -rupN linux-2.4.33-pre1/arch/i386/kernel/traps.c linux-2.4.33-pre1.i386-emu-rdtsc/arch/i386/kernel/traps.c
--- linux-2.4.33-pre1/arch/i386/kernel/traps.c	2005-11-17 13:27:30.000000000 +0100
+++ linux-2.4.33-pre1.i386-emu-rdtsc/arch/i386/kernel/traps.c	2005-12-29 21:55:00.000000000 +0100
@@ -388,7 +388,58 @@ DO_VM86_ERROR_INFO( 0, SIGFPE,  "divide 
 DO_VM86_ERROR( 3, SIGTRAP, "int3", int3)
 DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow)
 DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds)
+
+#ifdef CONFIG_X86_EMU_RDTSC
+unsigned int invalid_op_counter;
+static int handle_invalid_op(struct pt_regs *regs)
+{
+	unsigned char *eip;
+	unsigned char op[2];
+
+	++invalid_op_counter;
+
+	if (!user_mode(regs)) {
+		printk(KERN_ERR "%s: illegal opcode while in kernel mode\n",
+		       __FUNCTION__);
+		return 0;
+	}
+	eip = (unsigned char*)regs->eip;
+	if (get_user(op[0], eip+0) || get_user(op[1], eip+1)) {
+		printk(KERN_ERR "%s: unable to read opcode\n",
+		       __FUNCTION__);
+		return 0;
+	}
+	/* rpmq in Fedora Core 1 executes RDTSC :-( */
+	if (op[0] == 0x0F && op[1] == 0x31) {
+		static unsigned int fake_tsc_low;
+		regs->eax = ++fake_tsc_low;
+		regs->edx = 0;
+		regs->eip = (unsigned long)eip+2;
+		//printk(KERN_ERR "%s: RDTSC in pid %d (comm %s)\n",
+		//       __FUNCTION__, current->pid, current->comm);
+		return 1;
+	}
+	printk(KERN_ERR "%s: illegal opcode 0x%02X 0x%02X in pid %d (comm %s)\n",
+	       __FUNCTION__, op[0], op[1], current->pid, current->comm);
+	return 0;
+}
+
+asmlinkage void do_invalid_op(struct pt_regs *regs, long error_code)
+{
+	siginfo_t info;
+
+	if (handle_invalid_op(regs))
+		return;
+	info.si_signo = SIGILL;
+	info.si_errno = 0;
+	info.si_code = ILL_ILLOPN;
+	info.si_addr = (void *)regs->eip;
+	do_trap(6, SIGILL, "invalid operand", 0, regs, error_code, &info);
+}
+#else
 DO_ERROR_INFO( 6, SIGILL,  "invalid operand", invalid_op, ILL_ILLOPN, regs->eip)
+#endif
+
 DO_VM86_ERROR( 7, SIGSEGV, "device not available", device_not_available)
 DO_ERROR( 8, SIGSEGV, "double fault", double_fault)
 DO_ERROR( 9, SIGFPE,  "coprocessor segment overrun", coprocessor_segment_overrun)