Commit Graph

6 Commits

Author SHA1 Message Date
Qian Cai
cbedfe1134 asm-generic: fix -Wtype-limits compiler warnings
Commit d66acc39c7 ("bitops: Optimise get_order()") introduced a
compilation warning because "rx_frag_size" is an "ushort" while
PAGE_SHIFT here is 16.

The commit changed the get_order() to be a multi-line macro where
compilers insist to check all statements in the macro even when
__builtin_constant_p(rx_frag_size) will return false as "rx_frag_size"
is a module parameter.

In file included from ./arch/powerpc/include/asm/page_64.h:107,
                 from ./arch/powerpc/include/asm/page.h:242,
                 from ./arch/powerpc/include/asm/mmu.h:132,
                 from ./arch/powerpc/include/asm/lppaca.h:47,
                 from ./arch/powerpc/include/asm/paca.h:17,
                 from ./arch/powerpc/include/asm/current.h:13,
                 from ./include/linux/thread_info.h:21,
                 from ./arch/powerpc/include/asm/processor.h:39,
                 from ./include/linux/prefetch.h:15,
                 from drivers/net/ethernet/emulex/benet/be_main.c:14:
drivers/net/ethernet/emulex/benet/be_main.c: In function 'be_rx_cqs_create':
./include/asm-generic/getorder.h:54:9: warning: comparison is always
true due to limited range of data type [-Wtype-limits]
   (((n) < (1UL << PAGE_SHIFT)) ? 0 :  \
         ^
drivers/net/ethernet/emulex/benet/be_main.c:3138:33: note: in expansion
of macro 'get_order'
  adapter->big_page_size = (1 << get_order(rx_frag_size)) * PAGE_SIZE;
                                 ^~~~~~~~~

Fix it by moving all of this multi-line macro into a proper function,
and killing __get_order() off.

[akpm@linux-foundation.org: remove __get_order() altogether]
[cai@lca.pw: v2]
  Link: http://lkml.kernel.org/r/1564000166-31428-1-git-send-email-cai@lca.pw
Link: http://lkml.kernel.org/r/1563914986-26502-1-git-send-email-cai@lca.pw
Fixes: d66acc39c7 ("bitops: Optimise get_order()")
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: James Y Knight <jyknight@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-03 07:02:01 -07:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Joerg Roedel
b893485db9 bitops: Add missing parentheses to new get_order macro
The new get_order macro introcuded in commit

	d66acc39c7

does not use parentheses around all uses of the parameter n.
This causes new compile warnings, for example in the
amd_iommu_init.c function:

drivers/iommu/amd_iommu_init.c:561:6: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses]
drivers/iommu/amd_iommu_init.c:561:6: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses]

Fix those warnings by adding the missing parentheses.

Reported-by: Ingo Molnar <mingo@elte.hu>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Link: http://lkml.kernel.org/r/1330088295-28732-1-git-send-email-joerg.roedel@amd.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2012-02-24 10:39:27 -08:00
David Howells
d66acc39c7 bitops: Optimise get_order()
Optimise get_order() to use bit scanning instructions if such exist rather than
a loop.  Also, make it possible to use get_order() in static initialisations
too by building it on top of ilog2() in the constant parameter case.

This has been tested for i386 and x86_64 using the following userspace program,
and for FRV by making appropriate substitutions for fls() and fls64().  It will
abort if the case for get_order() deviates from the original except for the
order of 0, for which get_order() produces an undefined result.  This program
tests both dynamic and static parameters.

	#include <stdlib.h>
	#include <stdio.h>

	#ifdef __x86_64__
	#define BITS_PER_LONG 64
	#else
	#define BITS_PER_LONG 32
	#endif

	#define PAGE_SHIFT 12

	typedef unsigned long long __u64, u64;
	typedef unsigned int __u32, u32;
	#define noinline	__attribute__((noinline))

	static inline int fls(int x)
	{
		int bitpos = -1;

		asm("bsrl %1,%0"
		    : "+r" (bitpos)
		    : "rm" (x));
		return bitpos + 1;
	}

	static __always_inline int fls64(__u64 x)
	{
	#if BITS_PER_LONG == 64
		long bitpos = -1;

		asm("bsrq %1,%0"
		    : "+r" (bitpos)
		    : "rm" (x));
		return bitpos + 1;
	#else
		__u32 h = x >> 32, l = x;
		int bitpos = -1;

		asm("bsrl	%1,%0	\n"
		    "subl	%2,%0	\n"
		    "bsrl	%3,%0	\n"
		    : "+r" (bitpos)
		    : "rm" (l), "i"(32), "rm" (h));

		return bitpos + 33;
	#endif
	}

	static inline __attribute__((const))
	int __ilog2_u32(u32 n)
	{
		return fls(n) - 1;
	}

	static inline __attribute__((const))
	int __ilog2_u64(u64 n)
	{
		return fls64(n) - 1;
	}

	extern __attribute__((const, noreturn))
	int ____ilog2_NaN(void);

	#define ilog2(n)				\
	(						\
		__builtin_constant_p(n) ? (		\
			(n) < 1 ? ____ilog2_NaN() :	\
			(n) & (1ULL << 63) ? 63 :	\
			(n) & (1ULL << 62) ? 62 :	\
			(n) & (1ULL << 61) ? 61 :	\
			(n) & (1ULL << 60) ? 60 :	\
			(n) & (1ULL << 59) ? 59 :	\
			(n) & (1ULL << 58) ? 58 :	\
			(n) & (1ULL << 57) ? 57 :	\
			(n) & (1ULL << 56) ? 56 :	\
			(n) & (1ULL << 55) ? 55 :	\
			(n) & (1ULL << 54) ? 54 :	\
			(n) & (1ULL << 53) ? 53 :	\
			(n) & (1ULL << 52) ? 52 :	\
			(n) & (1ULL << 51) ? 51 :	\
			(n) & (1ULL << 50) ? 50 :	\
			(n) & (1ULL << 49) ? 49 :	\
			(n) & (1ULL << 48) ? 48 :	\
			(n) & (1ULL << 47) ? 47 :	\
			(n) & (1ULL << 46) ? 46 :	\
			(n) & (1ULL << 45) ? 45 :	\
			(n) & (1ULL << 44) ? 44 :	\
			(n) & (1ULL << 43) ? 43 :	\
			(n) & (1ULL << 42) ? 42 :	\
			(n) & (1ULL << 41) ? 41 :	\
			(n) & (1ULL << 40) ? 40 :	\
			(n) & (1ULL << 39) ? 39 :	\
			(n) & (1ULL << 38) ? 38 :	\
			(n) & (1ULL << 37) ? 37 :	\
			(n) & (1ULL << 36) ? 36 :	\
			(n) & (1ULL << 35) ? 35 :	\
			(n) & (1ULL << 34) ? 34 :	\
			(n) & (1ULL << 33) ? 33 :	\
			(n) & (1ULL << 32) ? 32 :	\
			(n) & (1ULL << 31) ? 31 :	\
			(n) & (1ULL << 30) ? 30 :	\
			(n) & (1ULL << 29) ? 29 :	\
			(n) & (1ULL << 28) ? 28 :	\
			(n) & (1ULL << 27) ? 27 :	\
			(n) & (1ULL << 26) ? 26 :	\
			(n) & (1ULL << 25) ? 25 :	\
			(n) & (1ULL << 24) ? 24 :	\
			(n) & (1ULL << 23) ? 23 :	\
			(n) & (1ULL << 22) ? 22 :	\
			(n) & (1ULL << 21) ? 21 :	\
			(n) & (1ULL << 20) ? 20 :	\
			(n) & (1ULL << 19) ? 19 :	\
			(n) & (1ULL << 18) ? 18 :	\
			(n) & (1ULL << 17) ? 17 :	\
			(n) & (1ULL << 16) ? 16 :	\
			(n) & (1ULL << 15) ? 15 :	\
			(n) & (1ULL << 14) ? 14 :	\
			(n) & (1ULL << 13) ? 13 :	\
			(n) & (1ULL << 12) ? 12 :	\
			(n) & (1ULL << 11) ? 11 :	\
			(n) & (1ULL << 10) ? 10 :	\
			(n) & (1ULL <<  9) ?  9 :	\
			(n) & (1ULL <<  8) ?  8 :	\
			(n) & (1ULL <<  7) ?  7 :	\
			(n) & (1ULL <<  6) ?  6 :	\
			(n) & (1ULL <<  5) ?  5 :	\
			(n) & (1ULL <<  4) ?  4 :	\
			(n) & (1ULL <<  3) ?  3 :	\
			(n) & (1ULL <<  2) ?  2 :	\
			(n) & (1ULL <<  1) ?  1 :	\
			(n) & (1ULL <<  0) ?  0 :	\
			____ilog2_NaN()			\
					   ) :		\
		(sizeof(n) <= 4) ?			\
		__ilog2_u32(n) :			\
		__ilog2_u64(n)				\
	 )

	static noinline __attribute__((const))
	int old_get_order(unsigned long size)
	{
		int order;

		size = (size - 1) >> (PAGE_SHIFT - 1);
		order = -1;
		do {
			size >>= 1;
			order++;
		} while (size);
		return order;
	}

	static noinline __attribute__((const))
	int __get_order(unsigned long size)
	{
		int order;
		size--;
		size >>= PAGE_SHIFT;
	#if BITS_PER_LONG == 32
		order = fls(size);
	#else
		order = fls64(size);
	#endif
		return order;
	}

	#define get_order(n)						\
	(								\
		__builtin_constant_p(n) ? (				\
			(n == 0UL) ? BITS_PER_LONG - PAGE_SHIFT :	\
			((n < (1UL << PAGE_SHIFT)) ? 0 :		\
			 ilog2((n) - 1) - PAGE_SHIFT + 1)		\
		) :							\
		__get_order(n)						\
	)

	#define order(N) \
		{ (1UL << N) - 1,	get_order((1UL << N) - 1)	},	\
		{ (1UL << N),		get_order((1UL << N))		},	\
		{ (1UL << N) + 1,	get_order((1UL << N) + 1)	}

	struct order {
		unsigned long n, order;
	};

	static const struct order order_table[] = {
		order(0),
		order(1),
		order(2),
		order(3),
		order(4),
		order(5),
		order(6),
		order(7),
		order(8),
		order(9),
		order(10),
		order(11),
		order(12),
		order(13),
		order(14),
		order(15),
		order(16),
		order(17),
		order(18),
		order(19),
		order(20),
		order(21),
		order(22),
		order(23),
		order(24),
		order(25),
		order(26),
		order(27),
		order(28),
		order(29),
		order(30),
		order(31),
	#if BITS_PER_LONG == 64
		order(32),
		order(33),
		order(34),
		order(35),
	#endif
		{ 0x2929 }
	};

	void check(int loop, unsigned long n)
	{
		unsigned long old, new;

		printf("[%2d]: %09lx | ", loop, n);

		old = old_get_order(n);
		new = get_order(n);

		printf("%3ld, %3ld\n", old, new);
		if (n != 0 && old != new)
			abort();
	}

	int main(int argc, char **argv)
	{
		const struct order *p;
		unsigned long n;
		int loop;

		for (loop = 0; loop <= BITS_PER_LONG - 1; loop++) {
			n = 1UL << loop;
			check(loop, n - 1);
			check(loop, n);
			check(loop, n + 1);
		}

		for (p = order_table; p->n != 0x2929; p++) {
			unsigned long old, new;

			old = old_get_order(p->n);
			new = p->order;
			printf("%09lx\t%3ld, %3ld\n", p->n, old, new);
			if (p->n != 0 && old != new)
				abort();
		}

		return 0;
	}

Disassembling the x86_64 version of the above code shows:

	0000000000400510 <old_get_order>:
	  400510:       48 83 ef 01             sub    $0x1,%rdi
	  400514:       b8 ff ff ff ff          mov    $0xffffffff,%eax
	  400519:       48 c1 ef 0b             shr    $0xb,%rdi
	  40051d:       0f 1f 00                nopl   (%rax)
	  400520:       83 c0 01                add    $0x1,%eax
	  400523:       48 d1 ef                shr    %rdi
	  400526:       75 f8                   jne    400520 <old_get_order+0x10>
	  400528:       f3 c3                   repz retq
	  40052a:       66 0f 1f 44 00 00       nopw   0x0(%rax,%rax,1)

	0000000000400530 <__get_order>:
	  400530:       48 83 ef 01             sub    $0x1,%rdi
	  400534:       48 c7 c0 ff ff ff ff    mov    $0xffffffffffffffff,%rax
	  40053b:       48 c1 ef 0c             shr    $0xc,%rdi
	  40053f:       48 0f bd c7             bsr    %rdi,%rax
	  400543:       83 c0 01                add    $0x1,%eax
	  400546:       c3                      retq
	  400547:       66 0f 1f 84 00 00 00    nopw   0x0(%rax,%rax,1)
	  40054e:       00 00

As can be seen, the new __get_order() function is simpler than the
old_get_order() function.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120220223928.16199.29548.stgit@warthog.procyon.org.uk
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 14:47:02 -08:00
David Howells
e0891a9816 bitops: Adjust the comment on get_order() to describe the size==0 case
Adjust the comment on get_order() to note that the result of passing a size of
0 results in an undefined value.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/20120220223917.16199.9416.stgit@warthog.procyon.org.uk
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2012-02-20 14:46:55 -08:00
Arnd Bergmann
5b17e1cd89 asm-generic: rename page.h and uaccess.h
The current asm-generic/page.h only contains the get_order
function, and asm-generic/uaccess.h only implements
unaligned accesses. This renames the file to getorder.h
and uaccess-unaligned.h to make room for new page.h
and uaccess.h file that will be usable by all simple
(e.g. nommu) architectures.

Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2009-06-11 21:02:17 +02:00