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>

3 files changed, 17 insertions, 12 deletions

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index dcfdcb3..2f6cfd4 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);
 }
 
diff --git a/arch/s390/kernel/os_info.c b/arch/s390/kernel/os_info.c
index f2fe18f..95fa5ac 100644
--- a/arch/s390/kernel/os_info.c
+++ b/arch/s390/kernel/os_info.c
@@ -60,7 +60,7 @@ void __init os_info_init(void)
 	os_info.version_minor = OS_INFO_VERSION_MINOR;
 	os_info.magic = OS_INFO_MAGIC;
 	os_info.csum = os_info_csum(&os_info);
-	copy_to_absolute_zero(&S390_lowcore.os_info, &ptr, sizeof(ptr));
+	memcpy_absolute(&S390_lowcore.os_info, &ptr, sizeof(ptr));
 }
 
 #ifdef CONFIG_CRASH_DUMP
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 06264ae..489d1d8 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -428,10 +428,12 @@ static void __init setup_lowcore(void)
 	lc->restart_fn = (unsigned long) do_restart;
 	lc->restart_data = 0;
 	lc->restart_source = -1UL;
-	memcpy(&S390_lowcore.restart_stack, &lc->restart_stack,
-	       4*sizeof(unsigned long));
-	copy_to_absolute_zero(&S390_lowcore.restart_psw,
-			      &lc->restart_psw, sizeof(psw_t));
+
+	/* Setup absolute zero lowcore */
+	memcpy_absolute(&S390_lowcore.restart_stack, &lc->restart_stack,
+			4 * sizeof(unsigned long));
+	memcpy_absolute(&S390_lowcore.restart_psw, &lc->restart_psw,
+			sizeof(lc->restart_psw));
 
 	set_prefix((u32)(unsigned long) lc);
 	lowcore_ptr[0] = lc;
@@ -598,7 +600,7 @@ static void __init setup_vmcoreinfo(void)
 #ifdef CONFIG_KEXEC
 	unsigned long ptr = paddr_vmcoreinfo_note();
 
-	copy_to_absolute_zero(&S390_lowcore.vmcore_info, &ptr, sizeof(ptr));
+	memcpy_absolute(&S390_lowcore.vmcore_info, &ptr, sizeof(ptr));
 #endif
 }