powerpc/fsl: Add macro to flush the branch predictor

commit 1cbf8990d79ff69da8ad09e8a3df014e1494462b upstream.

The BUCSR register can be used to invalidate the entries in the
branch prediction mechanisms.
Signed-off-by: NDiana Craciun <diana.craciun@nxp.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/powerpc/include/asm/ppc_asm.h

@@ -821,4 +821,14 @@ END_FTR_SECTION_IFCLR(CPU_FTR_601)
 	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 */