Hello. On 9/25/2014 1:26 PM, Paul Burton wrote:
The no-op cases of cop2_save & cop2_restore lead to the following warnings being emitted during build with recent versions of gcc (tested using gcc 4.8.3 from the Mentor Sourcery CodeBench 2014.05 toolchain):
In file included from ./arch/mips/include/asm/switch_to.h:18:0, from kernel/sched/core.c:78: kernel/sched/core.c: In function 'finish_task_switch': include/asm-generic/current.h:6:45: warning: value computed is not used [-Wunused-value] #define get_current() (current_thread_info()->task)
^
./arch/mips/include/asm/cop2.h:48:32: note: in definition of macro 'cop2_restore' #define cop2_restore(r) do { (r); } while (0) ^ include/asm-generic/current.h:7:17: note: in expansion of macro 'get_current' #define current get_current() ^ ./arch/mips/include/asm/switch_to.h:114:16: note: in expansion of macro 'current' cop2_restore(current); \ ^ kernel/sched/core.c:2225:2: note: in expansion of macro 'finish_arch_switch' finish_arch_switch(prev); ^
Avoid the warning by "using" the value by casting to void.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx> --- arch/mips/include/asm/cop2.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/mips/include/asm/cop2.h b/arch/mips/include/asm/cop2.h index 51f80bd..63b3468 100644 --- a/arch/mips/include/asm/cop2.h +++ b/arch/mips/include/asm/cop2.h @@ -37,15 +37,15 @@ extern void nlm_cop2_restore(struct nlm_cop2_state *); #define cop2_present 1 #define cop2_lazy_restore 1 -#define cop2_save(r) do { (r); } while (0) -#define cop2_restore(r) do { (r); } while (0) +#define cop2_save(r) do { (void)(r); } while (0) +#define cop2_restore(r) do { (void)(r); } while (0) #else #define cop2_present 0 #define cop2_lazy_restore 0 -#define cop2_save(r) do { (r); } while (0) -#define cop2_restore(r) do { (r); } while (0) +#define cop2_save(r) do { (void)(r); } while (0) +#define cop2_restore(r) do { (void)(r); } while (0) #endif
Looks like the definition are identical between 2 arms of #if, so why not move the macro definition out of #if, perhaps in later cleanup patch?
WBR, Sergei