[PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP()
Stephen Boyd
sboyd at kernel.org
Tue May 2 18:24:44 PDT 2023
Quoting Nathan Chancellor (2023-05-01 14:34:47)
> When building with clang + W=1, there is a warning around an internal
> comparison check within the FIELD_PREP() macro, due to a 32-bit variable
> comparison against ~0ull:
>
> drivers/clk/clk-sp7021.c:316:8: error: result of comparison of constant 18446744073709551615 with expression of type 'typeof (_Generic((_m), ...' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
> r0 |= HWM_FIELD_PREP(MASK_SEL_FRA, clk->p[SEL_FRA]);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/clk/clk-sp7021.c:45:15: note: expanded from macro 'HWM_FIELD_PREP'
> (_m << 16) | FIELD_PREP(_m, value); \
> ^~~~~~~~~~~~~~~~~~~~~
> include/linux/bitfield.h:114:3: note: expanded from macro 'FIELD_PREP'
> __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/bitfield.h:71:53: note: expanded from macro '__BF_FIELD_CHECK'
> BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
> note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
> include/linux/compiler_types.h:397:22: note: expanded from macro 'compiletime_assert'
> _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/compiler_types.h:385:23: note: expanded from macro '_compiletime_assert'
> __compiletime_assert(condition, msg, prefix, suffix)
> ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> include/linux/compiler_types.h:377:9: note: expanded from macro '__compiletime_assert'
> if (!(condition)) \
> ^~~~~~~~~
>
> This is expected given the tyoes of the input. Increase the size of the
> temporary variable in HWM_FIELD_PREP() to eliminate the warning, which
> follows the logic of commit cfd6fb45cfaf ("crypto: ccree - avoid
> out-of-range warnings from clang") for the same reasons.
>
> Signed-off-by: Nathan Chancellor <nathan at kernel.org>
> ---
Applied to clk-next
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