Cc: Fabio Estevam <[email protected]> (Fabio Estevam <[email protected]> is not valid anymore)
On 04/30/2018 09:09 AM, Heinrich Schuchardt wrote: > Without the patch gcc 8 produces: > warning: ignoring attribute ‘noreturn’ because it conflicts with > attribute ‘const’ [-Wattributes] > int ____ilog2_NaN(void); > > So let's update the include from Linux kernel v4.16. > > This removes static checks of ilog2() arguments. > > Signed-off-by: Heinrich Schuchardt <[email protected]> > --- > include/linux/log2.h | 63 +++++++++++++++++++++++++------------------- > 1 file changed, 36 insertions(+), 27 deletions(-) > > diff --git a/include/linux/log2.h b/include/linux/log2.h > index aa1de63090..41a1ae0109 100644 > --- a/include/linux/log2.h > +++ b/include/linux/log2.h > @@ -3,7 +3,10 @@ > * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved. > * Written by David Howells ([email protected]) > * > - * SPDX-License-Identifier: GPL-2.0+ > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * as published by the Free Software Foundation; either version > + * 2 of the License, or (at your option) any later version. > */ > > #ifndef _LINUX_LOG2_H > @@ -12,12 +15,6 @@ > #include <linux/types.h> > #include <linux/bitops.h> > > -/* > - * deal with unrepresentable constant logarithms > - */ > -extern __attribute__((const, noreturn)) > -int ____ilog2_NaN(void); > - > /* > * non-constant log of base 2 calculators > * - the arch may override these in asm/bitops.h if they can be implemented > @@ -40,19 +37,23 @@ int __ilog2_u64(u64 n) > } > #endif > > -/* > - * Determine whether some value is a power of two, where zero is > +/** > + * is_power_of_2() - check if a value is a power of two > + * @n: the value to check > + * > + * Determine whether some value is a power of two, where zero is > * *not* considered a power of two. > + * Return: true if @n is a power of 2, otherwise false. > */ > - > static inline __attribute__((const)) > bool is_power_of_2(unsigned long n) > { > return (n != 0 && ((n & (n - 1)) == 0)); > } > > -/* > - * round up to nearest power of two > +/** > + * __roundup_pow_of_two() - round up to nearest power of two > + * @n: value to round up > */ > static inline __attribute__((const)) > unsigned long __roundup_pow_of_two(unsigned long n) > @@ -60,8 +61,9 @@ unsigned long __roundup_pow_of_two(unsigned long n) > return 1UL << fls_long(n - 1); > } > > -/* > - * round down to nearest power of two > +/** > + * __rounddown_pow_of_two() - round down to nearest power of two > + * @n: value to round down > */ > static inline __attribute__((const)) > unsigned long __rounddown_pow_of_two(unsigned long n) > @@ -70,19 +72,19 @@ unsigned long __rounddown_pow_of_two(unsigned long n) > } > > /** > - * ilog2 - log of base 2 of 32-bit or a 64-bit unsigned value > - * @n - parameter > + * ilog2 - log base 2 of 32-bit or a 64-bit unsigned value > + * @n: parameter > * > * constant-capable log of base 2 calculation > * - this can be used to initialise global variables from constant data, > hence > - * the massive ternary operator construction > + * the massive ternary operator construction > * > * selects the appropriately-sized optimised version depending on sizeof(n) > */ > #define ilog2(n) \ > ( \ > __builtin_constant_p(n) ? ( \ > - (n) < 1 ? ____ilog2_NaN() : \ > + (n) < 2 ? 0 : \ > (n) & (1ULL << 63) ? 63 : \ > (n) & (1ULL << 62) ? 62 : \ > (n) & (1ULL << 61) ? 61 : \ > @@ -145,10 +147,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n) > (n) & (1ULL << 4) ? 4 : \ > (n) & (1ULL << 3) ? 3 : \ > (n) & (1ULL << 2) ? 2 : \ > - (n) & (1ULL << 1) ? 1 : \ > - (n) & (1ULL << 0) ? 0 : \ > - ____ilog2_NaN() \ > - ) : \ > + 1) : \ > (sizeof(n) <= 4) ? \ > __ilog2_u32(n) : \ > __ilog2_u64(n) \ > @@ -156,7 +155,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n) > > /** > * roundup_pow_of_two - round the given value up to nearest power of two > - * @n - parameter > + * @n: parameter > * > * round the given value up to the nearest power of two > * - the result is undefined when n == 0 > @@ -173,7 +172,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n) > > /** > * rounddown_pow_of_two - round the given value down to nearest power of two > - * @n - parameter > + * @n: parameter > * > * round the given value down to the nearest power of two > * - the result is undefined when n == 0 > @@ -186,6 +185,12 @@ unsigned long __rounddown_pow_of_two(unsigned long n) > __rounddown_pow_of_two(n) \ > ) > > +static inline __attribute_const__ > +int __order_base_2(unsigned long n) > +{ > + return n > 1 ? ilog2(n - 1) + 1 : 0; > +} > + > /** > * order_base_2 - calculate the (rounded up) base 2 order of the argument > * @n: parameter > @@ -199,7 +204,11 @@ unsigned long __rounddown_pow_of_two(unsigned long n) > * ob2(5) = 3 > * ... and so on. > */ > - > -#define order_base_2(n) ilog2(roundup_pow_of_two(n)) > - > +#define order_base_2(n) \ > +( \ > + __builtin_constant_p(n) ? ( \ > + ((n) == 0 || (n) == 1) ? 0 : \ > + ilog2((n) - 1) + 1) : \ > + __order_base_2(n) \ > +) > #endif /* _LINUX_LOG2_H */ > _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
