[S390] Use alternative user-copy operations for new hardware.

This introduces new user-copy operations which are optimized for
copying more than 256 Bytes on new hardware.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 18 insertions, 1 deletions

diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index 1ebaa338aa7e..a8bdd96494c7 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -250,6 +250,19 @@ startup_continue:
         oi      7(%r12),0x80            # set IDTE flag
 0:
 
+#
+# find out if we have the MVCOS instruction
+#
+        la      %r1,0f-.LPG1(%r13)      # set program check address
+        stg     %r1,__LC_PGM_NEW_PSW+8
+        .short  0xc800                  # mvcos 0(%r0),0(%r0),%r0
+        .short  0x0000
+        .short  0x0000
+0:      tm      0x8f,0x13               # special-operation exception?
+        bno     1f-.LPG1(%r13)          # if yes, MVCOS is present
+        oi      6(%r12),2               # set MVCOS flag
+1:
+
         lpswe .Lentry-.LPG1(13)         # jump to _stext in primary-space,
                                         # virtual and never return ...
         .align 16
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index e229af59976c..e3d9325f6022 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -647,7 +647,11 @@ setup_arch(char **cmdline_p)
 
         memory_end = memory_size;
 
-        memcpy(&uaccess, &uaccess_std, sizeof(uaccess));
+        if (MACHINE_HAS_MVCOS)
+                memcpy(&uaccess, &uaccess_mvcos, sizeof(uaccess));
+        else
+                memcpy(&uaccess, &uaccess_std, sizeof(uaccess));
+
         parse_early_param();
 
 #ifndef CONFIG_64BIT