powerpc/fsl: Add macro to flush the branch predictor

commit 1cbf8990d7 upstream.

The BUCSR register can be used to invalidate the entries in the
branch prediction mechanisms.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

arch/powerpc/include/asm/ppc_asm.h

@@ -780,4 +780,25 @@ END_FTR_SECTION_IFCLR(CPU_FTR_601)
 	.long 0x2400004c  /* rfid				*/
 #endif /* !CONFIG_PPC_BOOK3E */
 #endif /*  __ASSEMBLY__ */
+
+/*
+ * Helper macro for exception table entries
+ */
+#define EX_TABLE(_fault, _target)		\
+	stringify_in_c(.section __ex_table,"a";)\
+	stringify_in_c(.balign 4;)		\
+	stringify_in_c(.long (_fault) - . ;)	\
+	stringify_in_c(.long (_target) - . ;)	\
+	stringify_in_c(.previous)
+
+#ifdef CONFIG_PPC_FSL_BOOK3E
+#define BTB_FLUSH(reg)			\
+	lis reg,BUCSR_INIT@h;		\
+	ori reg,reg,BUCSR_INIT@l;	\
+	mtspr SPRN_BUCSR,reg;		\
+	isync;
+#else
+#define BTB_FLUSH(reg)
+#endif /* CONFIG_PPC_FSL_BOOK3E */
+
 #endif /* _ASM_POWERPC_PPC_ASM_H */