powerpc: Add helper functions for transactional memory context switching

Here we add the helper functions to be used when context switching.  These
allow us to fully reclaim and recheckpoint a transaction.

We introduce a new paca field called tm_scratch to help us store away register
values when doing the low level tm reclaim register save.

Signed-off-by: Matt Evans <[email protected]>
Signed-off-by: Michael Neuling <[email protected]>
Signed-off-by: Benjamin Herrenschmidt <[email protected]>

arch/powerpc/include/asm/reg.h

@@ -797,7 +797,7 @@
  *        HV mode in which case it is HSPRG0
  *
  * 64-bit server:
- *	- SPRG0 unused (reserved for HV on Power4)
+ *	- SPRG0 scratch for TM recheckpoint/reclaim (reserved for HV on Power4)
  *	- SPRG2 scratch for exception vectors
  *	- SPRG3 CPU and NUMA node for VDSO getcpu (user visible)
  *      - HSPRG0 stores PACA in HV mode

arch/powerpc/include/asm/tm.h

@@ -0,0 +1,20 @@
+/*
+ * Transactional memory support routines to reclaim and recheckpoint
+ * transactional process state.
+ *
+ * Copyright 2012 Matt Evans & Michael Neuling, IBM Corporation.
+ */
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+extern void do_load_up_transact_fpu(struct thread_struct *thread);
+extern void do_load_up_transact_altivec(struct thread_struct *thread);
+#endif
+
+extern void tm_enable(void);
+extern void tm_reclaim(struct thread_struct *thread,
+		       unsigned long orig_msr, uint8_t cause);
+extern void tm_recheckpoint(struct thread_struct *thread,
+			    unsigned long orig_msr);
+extern void tm_abort(uint8_t cause);
+extern void tm_save_sprs(struct thread_struct *thread);
+extern void tm_restore_sprs(struct thread_struct *thread);

arch/powerpc/kernel/Makefile

@@ -121,6 +121,8 @@ ifneq ($(CONFIG_PPC_INDIRECT_IO),y)
 obj-y				+= iomap.o
 endif
 
+obj64-$(CONFIG_PPC_TRANSACTIONAL_MEM)	+= tm.o
+
 obj-$(CONFIG_PPC64)		+= $(obj64-y)
 obj-$(CONFIG_PPC32)		+= $(obj32-y)