* [U-Boot] [PATCH 1/1] include: update log2 header from the Linux kernel
@ 2018-04-30 7:09 Heinrich Schuchardt
2018-04-30 9:35 ` [U-Boot] Fwd: " Heinrich Schuchardt
0 siblings, 1 reply; 2+ messages in thread
From: Heinrich Schuchardt @ 2018-04-30 7:09 UTC (permalink / raw)
To: u-boot
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 <xypron.glpk@gmx.de>
---
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 (dhowells at redhat.com)
*
- * 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 */
--
2.17.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [U-Boot] Fwd: [PATCH 1/1] include: update log2 header from the Linux kernel
2018-04-30 7:09 [U-Boot] [PATCH 1/1] include: update log2 header from the Linux kernel Heinrich Schuchardt
@ 2018-04-30 9:35 ` Heinrich Schuchardt
0 siblings, 0 replies; 2+ messages in thread
From: Heinrich Schuchardt @ 2018-04-30 9:35 UTC (permalink / raw)
To: u-boot
Cc: Fabio Estevam <fabio.estevam@nxp.com>
(Fabio Estevam <fabio.estevam@freescale.com> 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 <xypron.glpk@gmx.de>
> ---
> 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 (dhowells at redhat.com)
> *
> - * 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 */
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2018-04-30 9:35 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-04-30 7:09 [U-Boot] [PATCH 1/1] include: update log2 header from the Linux kernel Heinrich Schuchardt
2018-04-30 9:35 ` [U-Boot] Fwd: " Heinrich Schuchardt
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.