[PATCH] ia64: infinite loop in ia64_mca_wakeup_ipi_wait

This bugfix has been hiding inside the MCA TLB patches.

There is an infinite loop in ia64_mca_wakeup_ipi_wait() because
the compiler optimizes away the test at the bottom of the while
loop.  It does this because IA64_MCA_WAKEUP_VECTOR is 0xf0, so
irr_bit is known to be the constant 0x30, a.k.a. 48 in decimal.
So when the compiler looks at the expression:


It observes that 1' as unsigned
long.

arch/ia64/kernel/mca.c

@@ -828,7 +828,7 @@ ia64_mca_wakeup_ipi_wait(void)
 			irr = ia64_getreg(_IA64_REG_CR_IRR3);
 			break;
 		}
-	} while (!(irr & (1 << irr_bit))) ;
+	} while (!(irr & (1UL << irr_bit))) ;
 }
 
 /*