Re: [PATCH v3 5/5] linux/const.h: move BIT(_ULL) to linux/const.h for use in assembly

From: Masahiro Yamada
Date: Sun Feb 25 2018 - 21:13:56 EST


Hi test robot,


2018-02-24 14:00 GMT+09:00 kbuild test robot <lkp@xxxxxxxxx>:
> Hi Masahiro,
>
> I love your patch! Perhaps something to improve:
>
> [auto build test WARNING on linus/master]
> [also build test WARNING on v4.16-rc2 next-20180223]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/Masahiro-Yamada/linux-const-h-cleanups-of-macros-such-as-UL-_BITUL-BIT-etc/20180224-110702
> config: i386-allmodconfig (attached as .config)
> compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
> reproduce:
> # save the attached .config to linux build tree
> make ARCH=i386


I think this is a false positive report
because I see the same warning in the mainline.


The cause of the problem is
#define BNXT_RE_MAX_MR_SIZE_HIGH BIT(39)
in drivers/infiniband/hw/bnxt_re/bnxt_re.h


This causes -Wshift-count-overflow warning
if you compile test it on 32 bit arches.


I did not change the BIT() definition,
so this is not my fault.



> All warnings (new ones prefixed by >>):
>
> In file included from include/linux/const.h:4:0,
> from include/linux/bitops.h:4,
> from include/linux/kernel.h:11,
> from include/linux/interrupt.h:6,
> from drivers/infiniband/hw/bnxt_re/ib_verbs.c:39:
> drivers/infiniband/hw/bnxt_re/ib_verbs.c: In function 'bnxt_re_query_device':
>>> include/uapi/linux/const.h:28:27: warning: left shift count >= width of type [-Wshift-count-overflow]
> #define _BITUL(x) (_UL(1) << (x))
> ^
>>> include/linux/const.h:9:18: note: in expansion of macro '_BITUL'
> #define BIT(x) (_BITUL(x))
> ^~~~~~
> drivers/infiniband/hw/bnxt_re/bnxt_re.h:61:34: note: in expansion of macro 'BIT'
> #define BNXT_RE_MAX_MR_SIZE_HIGH BIT(39)
> ^~~
> drivers/infiniband/hw/bnxt_re/bnxt_re.h:62:30: note: in expansion of macro 'BNXT_RE_MAX_MR_SIZE_HIGH'
> #define BNXT_RE_MAX_MR_SIZE BNXT_RE_MAX_MR_SIZE_HIGH
> ^~~~~~~~~~~~~~~~~~~~~~~~
> drivers/infiniband/hw/bnxt_re/ib_verbs.c:149:25: note: in expansion of macro 'BNXT_RE_MAX_MR_SIZE'
> ib_attr->max_mr_size = BNXT_RE_MAX_MR_SIZE;
> ^~~~~~~~~~~~~~~~~~~
> drivers/infiniband/hw/bnxt_re/ib_verbs.c: In function 'bnxt_re_reg_user_mr':
>>> include/uapi/linux/const.h:28:27: warning: left shift count >= width of type [-Wshift-count-overflow]
> #define _BITUL(x) (_UL(1) << (x))
> ^
>>> include/linux/const.h:9:18: note: in expansion of macro '_BITUL'
> #define BIT(x) (_BITUL(x))
> ^~~~~~
> drivers/infiniband/hw/bnxt_re/bnxt_re.h:61:34: note: in expansion of macro 'BIT'
> #define BNXT_RE_MAX_MR_SIZE_HIGH BIT(39)
> ^~~
> drivers/infiniband/hw/bnxt_re/bnxt_re.h:62:30: note: in expansion of macro 'BNXT_RE_MAX_MR_SIZE_HIGH'
> #define BNXT_RE_MAX_MR_SIZE BNXT_RE_MAX_MR_SIZE_HIGH
> ^~~~~~~~~~~~~~~~~~~~~~~~
> drivers/infiniband/hw/bnxt_re/ib_verbs.c:3588:15: note: in expansion of macro 'BNXT_RE_MAX_MR_SIZE'
> if (length > BNXT_RE_MAX_MR_SIZE) {
> ^~~~~~~~~~~~~~~~~~~
>>> include/uapi/linux/const.h:28:27: warning: left shift count >= width of type [-Wshift-count-overflow]
> #define _BITUL(x) (_UL(1) << (x))
> ^
>>> include/linux/const.h:9:18: note: in expansion of macro '_BITUL'
> #define BIT(x) (_BITUL(x))
> ^~~~~~
> drivers/infiniband/hw/bnxt_re/bnxt_re.h:61:34: note: in expansion of macro 'BIT'
> #define BNXT_RE_MAX_MR_SIZE_HIGH BIT(39)
> ^~~
> drivers/infiniband/hw/bnxt_re/bnxt_re.h:62:30: note: in expansion of macro 'BNXT_RE_MAX_MR_SIZE_HIGH'
> #define BNXT_RE_MAX_MR_SIZE BNXT_RE_MAX_MR_SIZE_HIGH
> ^~~~~~~~~~~~~~~~~~~~~~~~
> drivers/infiniband/hw/bnxt_re/ib_verbs.c:3590:12: note: in expansion of macro 'BNXT_RE_MAX_MR_SIZE'
> length, BNXT_RE_MAX_MR_SIZE);
> ^~~~~~~~~~~~~~~~~~~
>
> vim +28 include/uapi/linux/const.h
>
> 5289f87f3 Masahiro Yamada 2018-02-22 27
> 4fac4e1b2 Masahiro Yamada 2018-02-22 @28 #define _BITUL(x) (_UL(1) << (x))
> 4fac4e1b2 Masahiro Yamada 2018-02-22 29 #define _BITULL(x) (_ULL(1) << (x))
> 2fc016c5b H. Peter Anvin 2013-04-27 30
>
> :::::: The code at line 28 was first introduced by commit
> :::::: 4fac4e1b26bc6cfec630fb48920c391d99a44940 linux/const.h: refactor _BITUL and _BITULL a bit
>
> :::::: TO: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> :::::: CC: 0day robot <fengguang.wu@xxxxxxxxx>
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation



--
Best Regards
Masahiro Yamada