s390: fix initrd corruptions with gcov/kcov instrumented kernels

The early C code within arch/s390/kernel/early.c saves ipl parameters
before the bss section is cleared. When doing that it jumps to code
that is potentially gcov/kcov instrumented. That code in turn will
corrupt an initrd that potentially may reside in the not yet ready to
be used bss section.

Instead of excluding more and more code from gcov/kcov instrumentation
provide an early memmove function which will be used to save ipl
parameters. The verification if these parameters are actually valid
will be done later.

Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 295bfb7124bc..ff3364a067ff 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1991,10 +1991,9 @@ void __init ipl_update_parameters(void)
 		diag308_set_works = 1;
 }
 
-void __init ipl_save_parameters(void)
+void __init ipl_verify_parameters(void)
 {
 	struct cio_iplinfo iplinfo;
-	void *src, *dst;
 
 	if (cio_get_iplinfo(&iplinfo))
 		return;
@@ -2005,10 +2004,6 @@ void __init ipl_save_parameters(void)
 	if (!iplinfo.is_qdio)
 		return;
 	ipl_flags |= IPL_PARMBLOCK_VALID;
-	src = (void *)(unsigned long)S390_lowcore.ipl_parmblock_ptr;
-	dst = (void *)IPL_PARMBLOCK_ORIGIN;
-	memmove(dst, src, PAGE_SIZE);
-	S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
 }
 
 static LIST_HEAD(rcall);