Commit Graph

16 Commits

Author SHA1 Message Date
Alexey Dobriyan
be5f3c7774 lib/kstrtox.c: use "unsigned int" more
gcc does generates stupid code sign extending data back and forth.  Help
by using "unsigned int".

	add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-61 (-61)
	function                                     old     new   delta
	_parse_integer                               128     123      -5

It _still_ does generate useless MOVSX but I don't know how to delete it:

0000000000000070 <_parse_integer>:
			...
  a0:   89 c2                   mov    edx,eax
  a2:   83 e8 30                sub    eax,0x30
  a5:   83 f8 09                cmp    eax,0x9
  a8:   76 11                   jbe    bb <_parse_integer+0x4b>
  aa:   83 ca 20                or     edx,0x20
  ad:   0f be c2      ===>      movsx  eax,dl         <===
			useless
  b0:   8d 50 9f                lea    edx,[rax-0x61]
  b3:   83 fa 05                cmp    edx,0x5

Patch also helps on embedded archs which generally only like "int".  On
arm "and 0xff" is generated which is waste because all values used in
comparisons are positive.

Link: http://lkml.kernel.org/r/20170514194720.GB32563@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:34 -07:00
Alexey Dobriyan
512750ef8b lib/kstrtox.c: delete end-of-string test
Standard "while (*s)" test is unnecessary because NUL won't pass
valid-digit test anyway.  Save one branch per parsed character.

Link: http://lkml.kernel.org/r/20170514193756.GA32563@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:34 -07:00
Linus Torvalds
7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Alexey Dobriyan
8cfd56d479 lib/kstrtox.c: smaller _parse_integer()
Set "overflow" bit upon encountering it instead of postponing to the end
of the conversion. Somehow gcc unwedges itself and generates better code:

	$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux
	_parse_integer                      177     139     -38

Inspired by patch from Zhaoxiu Zeng.

Link: http://lkml.kernel.org/r/20160826221920.GA1909@p183.telecom.by
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:30 -07:00
Kees Cook
a81a5a17d4 lib: add "on"/"off" support to kstrtobool
Add support for "on" and "off" when converting to boolean.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Amitkumar Karwar <akarwar@marvell.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Joe Perches <joe@perches.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nishant Sarmukadam <nishants@marvell.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Kees Cook
ef95159907 lib: move strtobool() to kstrtobool()
Create the kstrtobool_from_user() helper and move strtobool() logic into
the new kstrtobool() (matching all the other kstrto* functions).
Provides an inline wrapper for existing strtobool() callers.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Joe Perches <joe@perches.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Amitkumar Karwar <akarwar@marvell.com>
Cc: Nishant Sarmukadam <nishants@marvell.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Steve French <sfrench@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Alexey Dobriyan
2d2e4715a6 kstrto*: accept "-0" for signed conversion
strtol(3) et al accept "-0", so should we.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 13:29:01 -07:00
Felipe Contreras
ae2924a2bd lib/kstrtox.c: remove redundant cleanup
We can't reach the cleanup code unless the flag KSTRTOX_OVERFLOW is not
set, so there's not no point in clearing a bit that we know is not set.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Acked-by: Levente Kurusa <levex@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23 16:36:57 -08:00
Eldad Zack
4c925d6031 kstrto*: add documentation
As Bruce Fields pointed out, kstrto* is currently lacking kerneldoc
comments.  This patch adds kerneldoc comments to common variants of
kstrto*: kstrto(u)l, kstrto(u)ll and kstrto(u)int.

Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Joe Perches <joe@perches.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-17 17:15:22 -08:00
Paul Gortmaker
8bc3bcc93a lib: reduce the use of module.h wherever possible
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include.  Fix up any implicit
include dependencies that were being masked by module.h along
the way.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-03-07 15:04:04 -05:00
David Howells
690d137f44 Reduce the number of expensive division instructions done by _parse_integer()
_parse_integer() does one or two division instructions (which are slow)
per digit parsed to perform the overflow check.

Furthermore, these are particularly expensive examples of division
instruction as the number of clock cycles required to complete them may
go up with the position of the most significant set bit in the dividend:

	if (*res > div_u64(ULLONG_MAX - val, base))

which is as maximal as possible.

Worse, on 32-bit arches, more than one of these division instructions
may be required per digit.

So, assuming we don't support a base of more than 16, skip the check if the
top nibble of the result is not set at this point.

Signed-off-by: David Howells <dhowells@redhat.com>
[ Changed it to not dereference the pointer all the time - even if the
  compiler can and does optimize it away, the code just looks cleaner.
  And edited the top nybble test slightly to make the code generated on
  x86-64 better in the loop - test against a hoisted constant instead of
  shifting and testing the result ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-09 10:09:30 -08:00
Alexey Dobriyan
1dff46d698 lib/kstrtox: common code between kstrto*() and simple_strto*() functions
Currently termination logic (\0 or \n\0) is hardcoded in _kstrtoull(),
avoid that for code reuse between kstrto*() and simple_strtoull().
Essentially, make them different only in termination logic.

simple_strtoull() (and scanf(), BTW) ignores integer overflow, that's a
bug we currently don't have guts to fix, making KSTRTOX_OVERFLOW hack
necessary.

Almost forgot: patch shrinks code size by about ~80 bytes on x86_64.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:56 -07:00
Andy Shevchenko
75fb8f2693 lib: make _tolower() public
This function is required by *printf and kstrto* functions that are
located in the different modules.  This patch makes _tolower() public.
However, it's good idea to not use the helper outside of mentioned
functions.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25 20:57:16 -07:00
Alexey Dobriyan
c196e32a11 lib: add kstrto*_from_user()
There is quite a lot of code which does copy_from_user() + strict_strto*()
or simple_strto*() combo in slightly different ways.

Before doing conversions all over tree, let's get final API correct.

Enter kstrtoull_from_user() and friends.

Typical code which uses them looks very simple:

	TYPE val;
	int rv;

	rv = kstrtoTYPE_from_user(buf, count, 0, &val);
	if (rv < 0)
		return rv;
	[use val]
	return count;

There is a tiny semantic difference from the plain kstrto*() API -- the
latter allows any amount of leading zeroes, while the former copies data
into buffer on stack and thus allows leading zeroes as long as it fits
into buffer.

This shouldn't be a problem for typical usecase "echo 42 > /proc/x".

The point is to make reading one integer from userspace _very_ simple and
very bug free.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:52 -07:00
Alexey Dobriyan
78be959e38 kstrtox: simpler code in _kstrtoull()
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-14 16:06:55 -07:00
Alexey Dobriyan
33ee3b2e2e kstrto*: converting strings to integers done (hopefully) right
1. simple_strto*() do not contain overflow checks and crufty,
   libc way to indicate failure.
2. strict_strto*() also do not have overflow checks but the name and
   comments pretend they do.
3. Both families have only "long long" and "long" variants,
   but users want strtou8()
4. Both "simple" and "strict" prefixes are wrong:
   Simple doesn't exactly say what's so simple, strict should not exist
   because conversion should be strict by default.

The solution is to use "k" prefix and add convertors for more types.
Enter
	kstrtoull()
	kstrtoll()
	kstrtoul()
	kstrtol()
	kstrtouint()
	kstrtoint()

	kstrtou64()
	kstrtos64()
	kstrtou32()
	kstrtos32()
	kstrtou16()
	kstrtos16()
	kstrtou8()
	kstrtos8()

Include runtime testsuite (somewhat incomplete) as well.

strict_strto*() become deprecated, stubbed to kstrto*() and
eventually will be removed altogether.

Use kstrto*() in code today!

Note: on some archs _kstrtoul() and _kstrtol() are left in tree, even if
      they'll be unused at runtime. This is temporarily solution,
      because I don't want to hardcode list of archs where these
      functions aren't needed. Current solution with sizeof() and
      __alignof__ at least always works.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:14 -07:00