i386: convert hardware exception 12 to an interrupt gate

Handle stack segment exception with interrupt initially off.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/traps_32.c

@@ -640,7 +640,7 @@ DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip, 0)
 DO_ERROR(9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
 DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
-DO_TRAP(12, SIGBUS, "stack segment", stack_segment)
+DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
 DO_TRAP_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0, 0)
 DO_TRAP_INFO(32, SIGILL, "iret exception", iret_error, ILL_BADSTK, 0, 1)
 
@@ -1272,7 +1272,7 @@ void __init trap_init(void)
 	set_intr_gate(9, &coprocessor_segment_overrun);
 	set_intr_gate(10, &invalid_TSS);
 	set_intr_gate(11, &segment_not_present);
-	set_trap_gate(12, &stack_segment);
+	set_intr_gate(12, &stack_segment);
 	set_trap_gate(13, &general_protection);
 	set_intr_gate(14, &page_fault);
 	set_trap_gate(15, &spurious_interrupt_bug);