powerpc/fsl: Add macro to flush the branch predictor

BugLink: https://bugs.launchpad.net/bugs/1838116
commit 1cbf8990d79ff69da8ad09e8a3df014e1494462b 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index 13f7f4c0e1eae8f57abf5ef075c7e8b06f06b3ae..17f6b07568a2ea451cdcedc6b2eb9219b8b67d9f 100644 (file)
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -822,4 +822,14 @@ 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 */