linux-stable/arch/arm64
Will Deacon e1dfda9ced arm64: xchg: prevent warning if return value is unused
Some users of xchg() don't bother using the return value, which results
in a compiler warning like the following (from kgdb):

In file included from linux/arch/arm64/include/asm/atomic.h:27:0,
                 from include/linux/atomic.h:4,
                 from include/linux/spinlock.h:402,
                 from include/linux/seqlock.h:35,
                 from include/linux/time.h:5,
                 from include/uapi/linux/timex.h:56,
                 from include/linux/timex.h:56,
                 from include/linux/sched.h:19,
                 from include/linux/pid_namespace.h:4,
                 from kernel/debug/debug_core.c:30:
kernel/debug/debug_core.c: In function ‘kgdb_cpu_enter’:
linux/arch/arm64/include/asm/cmpxchg.h:75:3: warning: value computed is not used [-Wunused-value]
  ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
   ^
linux/arch/arm64/include/asm/atomic.h:132:30: note: in expansion of macro ‘xchg’
 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))

kernel/debug/debug_core.c:504:4: note: in expansion of macro ‘atomic_xchg’
    atomic_xchg(&kgdb_active, cpu);
    ^

This patch makes use of the same trick as we do for cmpxchg, by assigning
the return value to a dummy variable in the xchg() macro itself.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-05-09 17:00:00 +01:00
..
boot arm64: Mark the Applied Micro X-Gene SATA controller as DMA coherent 2014-05-03 22:20:35 +01:00
configs arm64: defconfig: Expand default enabled features 2014-02-07 17:17:28 +00:00
include arm64: xchg: prevent warning if return value is unused 2014-05-09 17:00:00 +01:00
kernel arm64: Clean up the default pgprot setting 2014-05-09 15:53:37 +01:00
kvm Merge tag 'kvm-3.15-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2014-04-02 14:50:10 -07:00
lib arm64: atomics: fix use of acquire + release for full barrier semantics 2014-02-07 16:45:43 +00:00
mm arm64: mm: Create gigabyte kernel logical mappings where possible 2014-05-09 16:10:58 +01:00
xen xen/arm,arm64: enable SWIOTLB_XEN 2013-10-10 13:40:44 +00:00
Kconfig arm64: Implement cache_line_size() based on CTR_EL0.CWG 2014-05-09 15:47:45 +01:00
Kconfig.debug arm64: Add missing Kconfig for CONFIG_STRICT_DEVMEM 2014-04-07 17:33:13 +01:00
Makefile arm64: big-endian: add big-endian support to top-level arch Makefile 2013-10-25 15:59:31 +01:00