-#endif
-
-#define setipl(__new_ipl) \
- __asm__ __volatile__("wrpr %0, %%pil" : : "r" (__new_ipl) : "memory")
-
-#define local_irq_disable() \
- __asm__ __volatile__("wrpr 15, %%pil" : : : "memory")
-
-#define local_irq_enable() \
- __asm__ __volatile__("wrpr 0, %%pil" : : : "memory")
-
-#define getipl() \
-({ unsigned long retval; __asm__ __volatile__("rdpr %%pil, %0" : "=r" (retval)); retval; })
-
-#define swap_pil(__new_pil) \
-({ unsigned long retval; \
- __asm__ __volatile__("rdpr %%pil, %0\n\t" \
- "wrpr %1, %%pil" \
- : "=&r" (retval) \
- : "r" (__new_pil) \
- : "memory"); \
- retval; \
-})
-
-#define read_pil_and_cli() \
-({ unsigned long retval; \
- __asm__ __volatile__("rdpr %%pil, %0\n\t" \
- "wrpr 15, %%pil" \
- : "=r" (retval) \
- : : "memory"); \
- retval; \
-})
-
-#define local_save_flags(flags) ((flags) = getipl())
-#define local_irq_save(flags) ((flags) = read_pil_and_cli())
-#define local_irq_restore(flags) setipl((flags))
-
-/* On sparc64 IRQ flags are the PIL register. A value of zero
- * means all interrupt levels are enabled, any other value means
- * only IRQ levels greater than that value will be received.
- * Consequently this means that the lowest IRQ level is one.
+/* These are here in an effort to more fully work around Spitfire Errata
+ * #51. Essentially, if a memory barrier occurs soon after a mispredicted
+ * branch, the chip can stop executing instructions until a trap occurs.
+ * Therefore, if interrupts are disabled, the chip can hang forever.
+ *
+ * It used to be believed that the memory barrier had to be right in the
+ * delay slot, but a case has been traced recently wherein the memory barrier
+ * was one instruction after the branch delay slot and the chip still hung.
+ * The offending sequence was the following in sym_wakeup_done() of the
+ * sym53c8xx_2 driver:
+ *
+ * call sym_ccb_from_dsa, 0
+ * movge %icc, 0, %l0
+ * brz,pn %o0, .LL1303
+ * mov %o0, %l2
+ * membar #LoadLoad
+ *
+ * The branch has to be mispredicted for the bug to occur. Therefore, we put
+ * the memory barrier explicitly into a "branch always, predicted taken"
+ * delay slot to avoid the problem case.