powerpc: Context switch the new EBB SPRs

This context switches the new Event Based Branching (EBB) SPRs.  The three new
SPRs are:
  - Event Based Branch Handler Register (EBBHR)
  - Event Based Branch Return Register (EBBRR)
  - Branch Event Status and Control Register (BESCR)
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/processor.h

@@ -281,6 +281,9 @@ struct thread_struct {
 #endif
 #ifdef CONFIG_PPC_BOOK3S_64
 	unsigned long	tar;
+	unsigned long	ebbrr;
+	unsigned long	ebbhr;
+	unsigned long	bescr;
 #endif
 };
 

arch/powerpc/include/asm/reg.h

@@ -663,6 +663,9 @@
 #define SPRN_MMCRH	316	/* Hypervisor monitor mode control register */
 #define SPRN_MMCRS	894	/* Supervisor monitor mode control register */
 #define SPRN_MMCRC	851	/* Core monitor mode control register */
+#define SPRN_EBBHR	804	/* Event based branch handler register */
+#define SPRN_EBBRR	805	/* Event based branch return register */
+#define SPRN_BESCR	806	/* Branch event status and control register */
 
 #define SPRN_PMC1	787
 #define SPRN_PMC2	788

arch/powerpc/kernel/asm-offsets.c

@@ -124,6 +124,9 @@ int main(void)
 
 #ifdef CONFIG_PPC_BOOK3S_64
 	DEFINE(THREAD_TAR, offsetof(struct thread_struct, tar));
+	DEFINE(THREAD_BESCR, offsetof(struct thread_struct, bescr));
+	DEFINE(THREAD_EBBHR, offsetof(struct thread_struct, ebbhr));
+	DEFINE(THREAD_EBBRR, offsetof(struct thread_struct, ebbrr));
 #endif
 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 	DEFINE(PACATMSCRATCH, offsetof(struct paca_struct, tm_scratch));

arch/powerpc/kernel/entry_64.S

@@ -458,6 +458,14 @@ BEGIN_FTR_SECTION
 	 */
 	mfspr	r0,SPRN_TAR
 	std	r0,THREAD_TAR(r3)
+
+	/* Event based branch registers */
+	mfspr	r0, SPRN_BESCR
+	std	r0, THREAD_BESCR(r3)
+	mfspr	r0, SPRN_EBBHR
+	std	r0, THREAD_EBBHR(r3)
+	mfspr	r0, SPRN_EBBRR
+	std	r0, THREAD_EBBRR(r3)
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 #endif
 
@@ -545,6 +553,14 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
 
 #ifdef CONFIG_PPC_BOOK3S_64
 BEGIN_FTR_SECTION
+	/* Event based branch registers */
+	ld	r0, THREAD_BESCR(r4)
+	mtspr	SPRN_BESCR, r0
+	ld	r0, THREAD_EBBHR(r4)
+	mtspr	SPRN_EBBHR, r0
+	ld	r0, THREAD_EBBRR(r4)
+	mtspr	SPRN_EBBRR, r0
+
 	ld	r0,THREAD_TAR(r4)
 	mtspr	SPRN_TAR,r0
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)