s390/kernel: Introduce memcpy_absolute() function

This patch introduces the new function memcpy_absolute() that allows to
copy memory using absolute addressing. This means that the prefix swap
does not apply when this function is used.

With this patch also all s390 kernel code that accesses absolute zero
now uses the new memcpy_absolute() function. The old and less generic
copy_to_absolute_zero() function is removed.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index dcfdcb3ea163..2f6cfd460cb6 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1528,12 +1528,15 @@ static struct shutdown_action __refdata dump_action = {
 
 static void dump_reipl_run(struct shutdown_trigger *trigger)
 {
-        u32 csum;
-
-        csum = csum_partial(reipl_block_actual, reipl_block_actual->hdr.len, 0);
-        copy_to_absolute_zero(&S390_lowcore.ipib_checksum, &csum, sizeof(csum));
-        copy_to_absolute_zero(&S390_lowcore.ipib, &reipl_block_actual,
-                              sizeof(reipl_block_actual));
+        struct {
+                void    *addr;
+                __u32   csum;
+        } __packed ipib;
+
+        ipib.csum = csum_partial(reipl_block_actual,
+                                 reipl_block_actual->hdr.len, 0);
+        ipib.addr = reipl_block_actual;
+        memcpy_absolute(&S390_lowcore.ipib, &ipib, sizeof(ipib));
         dump_run(trigger);
 }