s390: run user space and KVM guests with modified branch prediction
Define TIF_ISOLATE_BP and TIF_ISOLATE_BP_GUEST and add the necessary
plumbing in entry.S to be able to run user space and KVM guests with
limited branch prediction.
To switch a user space process to limited branch prediction the
s390_isolate_bp() function has to be call, and to run a vCPU of a KVM
guest associated with the current task with limited branch prediction
call s390_isolate_bp_guest().
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 5f37f9c..7f2953c 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -378,6 +378,9 @@ extern void memcpy_absolute(void *, void *, size_t);
memcpy_absolute(&(dest), &__tmp, sizeof(__tmp)); \
} while (0)
+extern int s390_isolate_bp(void);
+extern int s390_isolate_bp_guest(void);
+
#endif /* __ASSEMBLY__ */
#endif /* __ASM_S390_PROCESSOR_H */