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SubjectRe: [PATCH bpf 1/2] samples/bpf: Set flag __SANE_USERSPACE_TYPES__ for MIPS to fix build warnings
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On 01/14/2021 01:12 AM, Yonghong Song wrote:
>
>
> On 1/13/21 2:57 AM, Tiezhu Yang wrote:
>> MIPS needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
>> 'int-ll64.h' in arch/mips/include/uapi/asm/types.h and avoid compile
>> warnings when printing __u64 with %llu, %llx or %lld.
>
> could you mention which command produces the following warning?

make M=samples/bpf

>
>>
>> printf("0x%02x : %llu\n", key, value);
>> ~~~^ ~~~~~
>> %lu
>> printf("%s/%llx;", sym->name, addr);
>> ~~~^ ~~~~
>> %lx
>> printf(";%s %lld\n", key->waker, count);
>> ~~~^ ~~~~~
>> %ld
>>
>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>> ---
>> samples/bpf/Makefile | 4 ++++
>> tools/include/linux/types.h | 3 +++
>> 2 files changed, 7 insertions(+)
>>
>> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
>> index 26fc96c..27de306 100644
>> --- a/samples/bpf/Makefile
>> +++ b/samples/bpf/Makefile
>> @@ -183,6 +183,10 @@ BPF_EXTRA_CFLAGS := $(ARM_ARCH_SELECTOR)
>> TPROGS_CFLAGS += $(ARM_ARCH_SELECTOR)
>> endif
>> +ifeq ($(ARCH), mips)
>> +TPROGS_CFLAGS += -D__SANE_USERSPACE_TYPES__
>> +endif
>> +
>
> This change looks okay based on description in
> arch/mips/include/uapi/asm/types.h
>
> '''
> /*
> * We don't use int-l64.h for the kernel anymore but still use it for
> * userspace to avoid code changes.
> *
> * However, some user programs (e.g. perf) may not want this. They can
> * flag __SANE_USERSPACE_TYPES__ to get int-ll64.h here.
> */
> '''
>
>> TPROGS_CFLAGS += -Wall -O2
>> TPROGS_CFLAGS += -Wmissing-prototypes
>> TPROGS_CFLAGS += -Wstrict-prototypes
>> diff --git a/tools/include/linux/types.h b/tools/include/linux/types.h
>> index 154eb4e..e9c5a21 100644
>> --- a/tools/include/linux/types.h
>> +++ b/tools/include/linux/types.h
>> @@ -6,7 +6,10 @@
>> #include <stddef.h>
>> #include <stdint.h>
>> +#ifndef __SANE_USERSPACE_TYPES__
>> #define __SANE_USERSPACE_TYPES__ /* For PPC64, to get LL64 types */
>> +#endif
>
> What problem this patch fixed?

If add "TPROGS_CFLAGS += -D__SANE_USERSPACE_TYPES__" in
samples/bpf/Makefile, it appears the following error:

Auto-detecting system features:
... libelf: [ on ]
... zlib: [ on ]
... bpf: [ OFF ]

BPF API too old
make[3]: *** [Makefile:293: bpfdep] Error 1
make[2]: *** [Makefile:156: all] Error 2

With #ifndef __SANE_USERSPACE_TYPES__ in tools/include/linux/types.h,
the above error has gone.

> If this header is used, you can just
> change comment from "PPC64" to "PPC64/MIPS", right?

If include <linux/types.h> in the source files which have compile warnings
when printing __u64 with %llu, %llx or %lld, it has no effect due to
actually
it includes usr/include/linux/types.h instead of
tools/include/linux/types.h,
this is because the include-directories in samples/bpf/Makefile are searched
in the order, -I./usr/include is in the front of -I./tools/include.

So I think define __SANE_USERSPACE_TYPES__ for MIPS in samples/bpf/Makefile
is proper, at the same time, add #ifndef __SANE_USERSPACE_TYPES__ in
tools/include/linux/types.h can avoid build error and have no side effect.

I will send v2 later with mention in the commit message that this is
mips related.

Thanks,
Tiezhu

>
>> +
>> #include <asm/types.h>
>> #include <asm/posix_types.h>
>>

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