2008-03-05 12:01:48

by Martin Schwidefsky

[permalink] [raw]
Subject: [patch 03/10] Get rid of memcpy gcc warning workaround.

From: Heiko Carstens <[email protected]>

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 <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---

arch/s390/kernel/Makefile | 5 +++++
arch/s390/kernel/smp.c | 10 ++--------
2 files changed, 7 insertions(+), 8 deletions(-)

Index: quilt-2.6/arch/s390/kernel/Makefile
===================================================================
--- quilt-2.6.orig/arch/s390/kernel/Makefile
+++ quilt-2.6/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
Index: quilt-2.6/arch/s390/kernel/smp.c
===================================================================
--- quilt-2.6.orig/arch/s390/kernel/smp.c
+++ quilt-2.6/arch/s390/kernel/smp.c
@@ -629,14 +629,8 @@ static int __cpuinit smp_alloc_lowcore(i
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;


--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.