Re: [PATCH] kernel.h: Silence sparse warning in lower_32_bits

[Guenter Roeck]

On Fri, Aug 28, 2020 at 05:11:25PM +1000, Herbert Xu wrote:
> I keep getting sparse warnings in crypto such as:
> 

This patch results in the following compile error when compiling 
ppc:mpc85xx_defconfig.

Error log:
In file included from ./include/linux/list.h:9,
                 from ./include/linux/module.h:12,
                 from drivers/dma/fsldma.c:23:
drivers/dma/fsldma.h: In function 'fsl_ioread64':
./include/linux/kernel.h:189:37: error: invalid operands to binary & (have 'const u64 *' {aka 'const long long unsigned int *'} and 'unsigned int')
  189 | #define lower_32_bits(n) ((u32)((n) & 0xffffffff))
      |                                     ^
drivers/dma/fsldma.h:208:17: note: in expansion of macro 'lower_32_bits'
  208 |  u32 fsl_addr = lower_32_bits(addr);
      |                 ^~~~~~~~~~~~~
drivers/dma/fsldma.h: In function 'fsl_ioread64be':
./include/linux/kernel.h:189:37: error: invalid operands to binary & (have 'const u64 *' {aka 'const long long unsigned int *'} and 'unsigned int')
  189 | #define lower_32_bits(n) ((u32)((n) & 0xffffffff))
      |                                     ^
drivers/dma/fsldma.h:222:17: note: in expansion of macro 'lower_32_bits'
  222 |  u32 fsl_addr = lower_32_bits(addr);
      |                 ^~~~~~~~~~~~~
make[2]: *** [drivers/dma/fsldma.o] Error 1

Bisct log attached.

Guenter

---
# bad: [4d41ead6ead97c3730bbd186a601a64828668f01] Merge tag 'block-5.9-2020-08-28' of git://git.kernel.dk/linux-block
# good: [15bc20c6af4ceee97a1f90b43c0e386643c071b4] Merge tag 'tty-5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
git bisect start 'HEAD' '15bc20c6af4c'
# good: [5ec06b5c0d259a8c7c4376b121b2f62dfbfe57ef] Merge tag 'drm-fixes-2020-08-28' of git://anongit.freedesktop.org/drm/drm
git bisect good 5ec06b5c0d259a8c7c4376b121b2f62dfbfe57ef
# bad: [326e311b849426a95cac0149406efb2bbd13fa65] Merge tag 'pm-5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
git bisect bad 326e311b849426a95cac0149406efb2bbd13fa65
# good: [e30942859030199dab5ad73f95faac226133c639] Merge tag 'writeback_for_v5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
git bisect good e30942859030199dab5ad73f95faac226133c639
# bad: [96d454cd2c1668010406ea4c28ab915bcbb747f4] Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
git bisect bad 96d454cd2c1668010406ea4c28ab915bcbb747f4
# good: [e9ee186bb735bfc17fa81dbc9aebf268aee5b41e] KVM: arm64: Add kvm_extable for vaxorcism code
git bisect good e9ee186bb735bfc17fa81dbc9aebf268aee5b41e
# good: [71a7f8cb1ca4ca7214a700b1243626759b6c11d4] KVM: arm64: Set HCR_EL2.PTW to prevent AT taking synchronous exception
git bisect good 71a7f8cb1ca4ca7214a700b1243626759b6c11d4
# bad: [ef91bb196b0db1013ef8705367bc2d7944ef696b] kernel.h: Silence sparse warning in lower_32_bits
git bisect bad ef91bb196b0db1013ef8705367bc2d7944ef696b
# first bad commit: [ef91bb196b0db1013ef8705367bc2d7944ef696b] kernel.h: Silence sparse warning in lower_32_bits