Hello Tom,
On Mon, 30 Nov 2015 11:28:53 -0500, Tom Rini trini@konsulko.com wrote:
On Mon, Nov 30, 2015 at 11:03:53AM +0100, Heiko Schocher wrote:
Hello Jeroen,
Am 30.11.2015 um 10:20 schrieb Jeroen Hofstee:
Hello Heiko,
On 30-11-15 08:47, Heiko Schocher wrote:
compiling U-Boot for openrd_base_defconfig with gcc 5.x shows the following warning:
CC fs/ubifs/super.o In file included from fs/ubifs/ubifs.h:35:0, from fs/ubifs/super.c:37: fs/ubifs/super.c: In function 'atomic_inc': ./arch/arm/include/asm/atomic.h:55:2: warning: 'flags' is used uninitialized in this function [-Wuninitialized] local_irq_save(flags); ^ fs/ubifs/super.c: In function 'atomic_dec': ./arch/arm/include/asm/atomic.h:64:2: warning: 'flags' is used uninitialized in this function [-Wuninitialized] local_irq_save(flags); ^ CC fs/ubifs/sb.o [...] CC fs/ubifs/lpt.o In file included from include/linux/bitops.h:123:0, from include/common.h:20, from include/ubi_uboot.h:17, from fs/ubifs/ubifs.h:37, from fs/ubifs/lpt.c:35: fs/ubifs/lpt.c: In function 'test_and_set_bit': ./arch/arm/include/asm/bitops.h:57:2: warning: 'flags' is used uninitialized in this function [-Wuninitialized] local_irq_save(flags); ^ CC fs/ubifs/lpt_commit.o In file included from include/linux/bitops.h:123:0, from include/common.h:20, from include/ubi_uboot.h:17, from fs/ubifs/ubifs.h:37, from fs/ubifs/lpt_commit.c:26: fs/ubifs/lpt_commit.c: In function 'test_and_set_bit': ./arch/arm/include/asm/bitops.h:57:2: warning: 'flags' is used uninitialized in this function [-Wuninitialized] local_irq_save(flags); ^ CC fs/ubifs/scan.o CC fs/ubifs/lprops.o CC fs/ubifs/tnc.o In file included from include/linux/bitops.h:123:0, from include/common.h:20, from include/ubi_uboot.h:17, from fs/ubifs/ubifs.h:37, from fs/ubifs/tnc.c:30: fs/ubifs/tnc.c: In function 'test_and_set_bit': ./arch/arm/include/asm/bitops.h:57:2: warning: 'flags' is used uninitialized in this function [-Wuninitialized] local_irq_save(flags); ^ CC fs/ubifs/tnc_misc.o
Fix it.
Signed-off-by: Heiko Schocher hs@denx.de
arch/arm/include/asm/atomic.h | 14 +++++++------- arch/arm/include/asm/bitops.h | 4 ++-- 2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h index 34c07fe..9b79506 100644 --- a/arch/arm/include/asm/atomic.h +++ b/arch/arm/include/asm/atomic.h @@ -32,7 +32,7 @@ typedef struct { volatile int counter; } atomic_t; static inline void atomic_add(int i, volatile atomic_t *v) {
- unsigned long flags;
- unsigned long flags = 0; local_irq_save(flags); v->counter += i;
@@ -41,7 +41,7 @@ static inline void atomic_add(int i, volatile atomic_t *v)
Since flags is an "out" argument, something else must be wrong. There should be no need to initialize it, since local_irq_save should do that afaik.
yes, you are right, it should be, but gcc 5.x seems to have problems with it ... compiled code size for the openrd_base config is same with my patch ...
Hmm... for the openrd_base compile local_irq_save() is used from: arch/arm/thumb1/include/asm/proc-armv/system.h
with: static inline void local_irq_save( unsigned long flags __attribute__((unused))) { __asm__ __volatile__ ("" : : : "memory"); }
flasg marked as unused ... seems correct to me, but I have no idea, why gcc 5.x prints a warning ... any ideas?
Well, gcc does get more vigerous in its checking now and yeah, it feels like it's flagging false positives. In this case I think the answer is that we need to nop out the various calls a bit harder on ARM. Glancing at the kernel, I think for thumb1 we should just do what we do for non-thumb, or translate that into thumb1 only code.
Not sure I'm following what you mean, both about nop-ing out and about thumb-1. Can you clarify?
Tom
Amicalement,