[S390] Get rid of memcpy gcc warning workaround.

Compile smp.o with -Wno-nonnull so gcc stops warning about memcpy
being used with a null parameter. Also remove the workaround code
and use a char * cast instead of a void * cast to do computations.

Cc: Bastian Blank <bastian@waldi.eu.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index b3b650a93c7c752f6d95c5b789beef5cfbd99589..4d3e38392cb1486dd11db7868098ec30c22808b4 100644 (file)
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -4,6 +4,11 @@
 
 EXTRA_AFLAGS   := -traditional
 
+#
+# Passing null pointers is ok for smp code, since we access the lowcore here.
+#
+CFLAGS_smp.o   := -Wno-nonnull
+
 obj-y  :=  bitmap.o traps.o time.o process.o base.o early.o \
             setup.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o \
            semaphore.o s390_ext.o debug.o irq.o ipl.o dis.o diag.o

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 818bd09c0260e05fb3a58eb2764f88e8f055a585..8f894d380a626316c68aeb073043f027abdcfee6 100644 (file)
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -629,14 +629,8 @@ static int __cpuinit smp_alloc_lowcore(int cpu)
        panic_stack = __get_free_page(GFP_KERNEL);
        if (!panic_stack || !async_stack)
                goto out;
-       /*
-        * Only need to copy the first 512 bytes from address 0. But since
-        * the compiler emits a warning if src == NULL for memcpy use copy_page
-        * instead. Copies more than needed but this code is not performance
-        * critical.
-        */
-       copy_page(lowcore, &S390_lowcore);
-       memset((void *)lowcore + 512, 0, sizeof(*lowcore) - 512);
+       memcpy(lowcore, &S390_lowcore, 512);
+       memset((char *)lowcore + 512, 0, sizeof(*lowcore) - 512);
        lowcore->async_stack = async_stack + ASYNC_SIZE;
        lowcore->panic_stack = panic_stack + PAGE_SIZE;