* [PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP()
@ 2023-05-01 21:34 Nathan Chancellor
2023-05-01 21:37 ` Nathan Chancellor
2023-05-03 1:24 ` Stephen Boyd
0 siblings, 2 replies; 5+ messages in thread
From: Nathan Chancellor @ 2023-05-01 21:34 UTC (permalink / raw)
To: qinjian, mturquette, sboyd
Cc: ndesaulniers, trix, linux-arm-kernel, linux-clk, llvm, patches,
Nathan Chancellor
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@kernel.org>
---
drivers/clk/clk-sp7021.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/clk-sp7021.c b/drivers/clk/clk-sp7021.c
index 8fec14120105..11d22043ddd7 100644
--- a/drivers/clk/clk-sp7021.c
+++ b/drivers/clk/clk-sp7021.c
@@ -41,7 +41,7 @@ enum {
/* HIWORD_MASK FIELD_PREP */
#define HWM_FIELD_PREP(mask, value) \
({ \
- u32 _m = mask; \
+ u64 _m = mask; \
(_m << 16) | FIELD_PREP(_m, value); \
})
---
base-commit: d54c1fd4a51e8fbc7f9da86b0cd338a4f7cd2bb2
change-id: 20230501-sp7021-field_prep-warning-223f17aeea8e
Best regards,
--
Nathan Chancellor <nathan@kernel.org>
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP()
2023-05-01 21:34 [PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP() Nathan Chancellor
@ 2023-05-01 21:37 ` Nathan Chancellor
2023-05-01 22:03 ` Nick Desaulniers
2023-05-03 1:24 ` Stephen Boyd
1 sibling, 1 reply; 5+ messages in thread
From: Nathan Chancellor @ 2023-05-01 21:37 UTC (permalink / raw)
To: qinjian, mturquette, sboyd
Cc: ndesaulniers, trix, linux-arm-kernel, linux-clk, llvm, patches
On Mon, May 01, 2023 at 02:34:47PM -0700, Nathan Chancellor wrote:
> 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.
Gah, I forgot:
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/202303221947.pXP2v4xJ-lkp@intel.com/
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
> drivers/clk/clk-sp7021.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk-sp7021.c b/drivers/clk/clk-sp7021.c
> index 8fec14120105..11d22043ddd7 100644
> --- a/drivers/clk/clk-sp7021.c
> +++ b/drivers/clk/clk-sp7021.c
> @@ -41,7 +41,7 @@ enum {
> /* HIWORD_MASK FIELD_PREP */
> #define HWM_FIELD_PREP(mask, value) \
> ({ \
> - u32 _m = mask; \
> + u64 _m = mask; \
> (_m << 16) | FIELD_PREP(_m, value); \
> })
>
>
> ---
> base-commit: d54c1fd4a51e8fbc7f9da86b0cd338a4f7cd2bb2
> change-id: 20230501-sp7021-field_prep-warning-223f17aeea8e
>
> Best regards,
> --
> Nathan Chancellor <nathan@kernel.org>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP()
2023-05-01 21:37 ` Nathan Chancellor
@ 2023-05-01 22:03 ` Nick Desaulniers
2023-05-01 22:15 ` Nick Desaulniers
0 siblings, 1 reply; 5+ messages in thread
From: Nick Desaulniers @ 2023-05-01 22:03 UTC (permalink / raw)
To: Nathan Chancellor
Cc: qinjian, mturquette, sboyd, trix, linux-arm-kernel, linux-clk,
llvm, patches, Arnd Bergmann
On Mon, May 1, 2023 at 2:37 PM Nathan Chancellor <nathan@kernel.org> wrote:
>
> On Mon, May 01, 2023 at 02:34:47PM -0700, Nathan Chancellor wrote:
> > 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
s/tyoes/types/
Thanks for the patch!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Nathan, do you think anything can be done in FIELD_PREP or even
__BF_FIELD_CHECK using _Static_assert (or static_assert from
include/linux/build_bug.h) to help elucidate to developers that their
mask is too small? I guess the line 71 of include/linux/bitfield.h
that is trying to warn via BUILD_BUG_ON is itself triggering a
-Wtautological-constant-out-of-range-compare warning that is perhaps
distracting from what the issue is?
If you're able to reproduce the issue locally still, does this seem to work?
```
diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index ebfa12f69501..762a27b5ae15 100644
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -62,15 +62,15 @@
#define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx) \
({ \
+ static_assert(__bf_cast_unsigned(_mask, _mask) <= \
+ __bf_cast_unsigned(_reg, ~0ull), \
+ _pfx "type of reg too small for mask"); \
BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask), \
_pfx "mask is not constant"); \
BUILD_BUG_ON_MSG((_mask) == 0, _pfx "mask is zero"); \
BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \
_pfx "value too large for the field"); \
- BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \
- __bf_cast_unsigned(_reg, ~0ull), \
- _pfx "type of reg too small for mask"); \
__BUILD_BUG_ON_NOT_POWER_OF_2((_mask) + \
(1ULL << __bf_shf(_mask))); \
})
```
> > 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.
>
> Gah, I forgot:
>
> Reported-by: kernel test robot <lkp@intel.com>
> Link: https://lore.kernel.org/202303221947.pXP2v4xJ-lkp@intel.com/
>
> > Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> > ---
> > drivers/clk/clk-sp7021.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/clk/clk-sp7021.c b/drivers/clk/clk-sp7021.c
> > index 8fec14120105..11d22043ddd7 100644
> > --- a/drivers/clk/clk-sp7021.c
> > +++ b/drivers/clk/clk-sp7021.c
> > @@ -41,7 +41,7 @@ enum {
> > /* HIWORD_MASK FIELD_PREP */
> > #define HWM_FIELD_PREP(mask, value) \
> > ({ \
> > - u32 _m = mask; \
> > + u64 _m = mask; \
> > (_m << 16) | FIELD_PREP(_m, value); \
> > })
> >
> >
> > ---
> > base-commit: d54c1fd4a51e8fbc7f9da86b0cd338a4f7cd2bb2
> > change-id: 20230501-sp7021-field_prep-warning-223f17aeea8e
> >
> > Best regards,
> > --
> > Nathan Chancellor <nathan@kernel.org>
> >
--
Thanks,
~Nick Desaulniers
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP()
2023-05-01 22:03 ` Nick Desaulniers
@ 2023-05-01 22:15 ` Nick Desaulniers
0 siblings, 0 replies; 5+ messages in thread
From: Nick Desaulniers @ 2023-05-01 22:15 UTC (permalink / raw)
To: Nathan Chancellor
Cc: qinjian, mturquette, sboyd, trix, linux-arm-kernel, linux-clk,
llvm, patches, Arnd Bergmann
On Mon, May 1, 2023 at 3:03 PM Nick Desaulniers <ndesaulniers@google.com> wrote:
>
> On Mon, May 1, 2023 at 2:37 PM Nathan Chancellor <nathan@kernel.org> wrote:
> >
> > On Mon, May 01, 2023 at 02:34:47PM -0700, Nathan Chancellor wrote:
> > > 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
>
> s/tyoes/types/
>
> Thanks for the patch!
>
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
>
> Nathan, do you think anything can be done in FIELD_PREP or even
> __BF_FIELD_CHECK using _Static_assert (or static_assert from
> include/linux/build_bug.h) to help elucidate to developers that their
> mask is too small? I guess the line 71 of include/linux/bitfield.h
> that is trying to warn via BUILD_BUG_ON is itself triggering a
> -Wtautological-constant-out-of-range-compare warning that is perhaps
> distracting from what the issue is?
>
> If you're able to reproduce the issue locally still, does this seem to work?
> ```
> diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
> index ebfa12f69501..762a27b5ae15 100644
> --- a/include/linux/bitfield.h
> +++ b/include/linux/bitfield.h
> @@ -62,15 +62,15 @@
>
> #define __BF_FIELD_CHECK(_mask, _reg, _val, _pfx) \
> ({ \
> + static_assert(__bf_cast_unsigned(_mask, _mask) <= \
> + __bf_cast_unsigned(_reg, ~0ull), \
> + _pfx "type of reg too small for mask"); \
> BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask), \
> _pfx "mask is not constant"); \
> BUILD_BUG_ON_MSG((_mask) == 0, _pfx "mask is zero"); \
> BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
> ~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \
> _pfx "value too large for the field"); \
> - BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \
> - __bf_cast_unsigned(_reg, ~0ull), \
> - _pfx "type of reg too small for mask"); \
> __BUILD_BUG_ON_NOT_POWER_OF_2((_mask) + \
> (1ULL << __bf_shf(_mask))); \
> })
>
> ```
Hmmm....maybe not:
```
drivers/gpu/drm/i915/i915_hwmon.c:97:14: error: static assertion
expression is not an integral constant expression
reg_value = REG_FIELD_GET(field_msk, reg_value);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/i915/i915_reg_defs.h:87:44: note: expanded from
macro 'REG_FIELD_GET'
#define REG_FIELD_GET(__mask, __val) ((u32)FIELD_GET(__mask, __val))
^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/bitfield.h:154:3: note: expanded from macro 'FIELD_GET'
__BF_FIELD_CHECK(_mask, _reg, 0U, "FIELD_GET: "); \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/bitfield.h:65:17: note: expanded from macro '__BF_FIELD_CHECK'
static_assert(__bf_cast_unsigned(_mask, _mask) <= \
~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/bitfield.h:61:70: note: expanded from macro '__bf_cast_unsigned'
#define __bf_cast_unsigned(type, x) ((__unsigned_scalar_typeof(type))(x))
^
./include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
#define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
#define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
^~~~
```
so there's probably a use of REG_FIELD_GET that is
__builtin_constant_p but not an integral constant expression. That's
too bad...
>
>
> > > 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.
> >
> > Gah, I forgot:
> >
> > Reported-by: kernel test robot <lkp@intel.com>
> > Link: https://lore.kernel.org/202303221947.pXP2v4xJ-lkp@intel.com/
> >
> > > Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> > > ---
> > > drivers/clk/clk-sp7021.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/clk/clk-sp7021.c b/drivers/clk/clk-sp7021.c
> > > index 8fec14120105..11d22043ddd7 100644
> > > --- a/drivers/clk/clk-sp7021.c
> > > +++ b/drivers/clk/clk-sp7021.c
> > > @@ -41,7 +41,7 @@ enum {
> > > /* HIWORD_MASK FIELD_PREP */
> > > #define HWM_FIELD_PREP(mask, value) \
> > > ({ \
> > > - u32 _m = mask; \
> > > + u64 _m = mask; \
> > > (_m << 16) | FIELD_PREP(_m, value); \
> > > })
> > >
> > >
> > > ---
> > > base-commit: d54c1fd4a51e8fbc7f9da86b0cd338a4f7cd2bb2
> > > change-id: 20230501-sp7021-field_prep-warning-223f17aeea8e
> > >
> > > Best regards,
> > > --
> > > Nathan Chancellor <nathan@kernel.org>
> > >
>
>
>
> --
> Thanks,
> ~Nick Desaulniers
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP()
2023-05-01 21:34 [PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP() Nathan Chancellor
2023-05-01 21:37 ` Nathan Chancellor
@ 2023-05-03 1:24 ` Stephen Boyd
1 sibling, 0 replies; 5+ messages in thread
From: Stephen Boyd @ 2023-05-03 1:24 UTC (permalink / raw)
To: Nathan Chancellor, mturquette, qinjian
Cc: ndesaulniers, trix, linux-arm-kernel, linux-clk, llvm, patches,
Nathan Chancellor
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@kernel.org>
> ---
Applied to clk-next
^ permalink raw reply [flat|nested] 5+ messages in thread
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2023-05-01 21:34 [PATCH] clk: sp7021: Adjust width of _m in HWM_FIELD_PREP() Nathan Chancellor
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