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  1. 21 1月, 2013 1 次提交
  3. 21 12月, 2012 1 次提交
    • G
      linux/kernel.h: fix DIV_ROUND_CLOSEST with unsigned divisors · c4e18497
      由 Guenter Roeck 提交于 
      Commit 263a523d ("linux/kernel.h: Fix warning seen with W=1 due to
change in DIV_ROUND_CLOSEST") fixes a warning seen with W=1 due to
change in DIV_ROUND_CLOSEST.

Unfortunately, the C compiler converts divide operations with unsigned
divisors to unsigned, even if the dividend is signed and negative (for
example, -10 / 5U = 858993457).  The C standard says "If one operand has
unsigned int type, the other operand is converted to unsigned int", so
the compiler is not to blame.  As a result, DIV_ROUND_CLOSEST(0, 2U) and
similar operations now return bad values, since the automatic conversion
of expressions such as "0 - 2U/2" to unsigned was not taken into
account.

Fix by checking for the divisor variable type when deciding which
operation to perform.  This fixes DIV_ROUND_CLOSEST(0, 2U), but still
returns bad values for negative dividends divided by unsigned divisors.
Mark the latter case as unsupported.

One observed effect of this problem is that the s2c_hwmon driver reports
a value of 4198403 instead of 0 if the ADC reads 0.

Other impact is unpredictable.  Problem is seen if the divisor is an
unsigned variable or constant and the dividend is less than (divisor/2).
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Reported-by: NJuergen Beisert <jbe@pengutronix.de>
Tested-by: NJuergen Beisert <jbe@pengutronix.de>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: <stable@vger.kernel.org>	[3.7.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c4e18497
  5. 18 12月, 2012 1 次提交
  7. 12 12月, 2012 2 次提交
  9. 03 12月, 2012 1 次提交
    • J
      linux/kernel.h: define SYMBOL_PREFIX · cbdbf2ab
      由 James Hogan 提交于 
      Define SYMBOL_PREFIX to be the same as CONFIG_SYMBOL_PREFIX if set by
the architecture, or "" otherwise. This avoids the need for ugly #ifdefs
whenever symbols are referenced in asm blocks.
Signed-off-by: NJames Hogan <james.hogan@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Joe Perches <joe@perches.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      cbdbf2ab
  11. 01 11月, 2012 1 次提交
  13. 13 10月, 2012 1 次提交
  15. 19 9月, 2012 1 次提交
    • G
      linux/kernel.h: Fix warning seen with W=1 due to change in DIV_ROUND_CLOSEST · 263a523d
      由 Guenter Roeck 提交于 
      After commit b6d86d3d (Fix DIV_ROUND_CLOSEST to support negative dividends),
the following warning is seen if the kernel is compiled with W=1 (-Wextra):

warning: comparison of unsigned expression >= 0 is always true

The warning is due to the test '((typeof(x))-1) >= 0', which is used to detect
if the variable type is unsigned. Research on the web suggests that the warning
disappears if '>' instead of '>=' is used for the comparison.

Tests after changing the macro along that line show that the warning is gone,
and that the result is still correct:

i=-4: DIV_ROUND_CLOSEST(i, 2)=-2
i=-3: DIV_ROUND_CLOSEST(i, 2)=-2
i=-2: DIV_ROUND_CLOSEST(i, 2)=-1
i=-1: DIV_ROUND_CLOSEST(i, 2)=-1
i=0: DIV_ROUND_CLOSEST(i, 2)=0
i=1: DIV_ROUND_CLOSEST(i, 2)=1
i=2: DIV_ROUND_CLOSEST(i, 2)=1
i=3: DIV_ROUND_CLOSEST(i, 2)=2
i=4: DIV_ROUND_CLOSEST(i, 2)=2

Code size is the same as before.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Acked-by: NJean Delvare <khali@linux-fr.org>
      263a523d
  17. 02 9月, 2012 1 次提交
  19. 22 7月, 2012 1 次提交
  21. 01 6月, 2012 1 次提交
  23. 25 5月, 2012 1 次提交
  25. 24 4月, 2012 1 次提交
    • S
      tracing: Add percpu buffers for trace_printk() · 07d777fe
      由 Steven Rostedt 提交于 
      Currently, trace_printk() uses a single buffer to write into
to calculate the size and format needed to save the trace. To
do this safely in an SMP environment, a spin_lock() is taken
to only allow one writer at a time to the buffer. But this could
also affect what is being traced, and add synchronization that
would not be there otherwise.

Ideally, using percpu buffers would be useful, but since trace_printk()
is only used in development, having per cpu buffers for something
never used is a waste of space. Thus, the use of the trace_bprintk()
format section is changed to be used for static fmts as well as dynamic ones.
Then at boot up, we can check if the section that holds the trace_printk
formats is non-empty, and if it does contain something, then we
know a trace_printk() has been added to the kernel. At this time
the trace_printk per cpu buffers are allocated. A check is also
done at module load time in case a module is added that contains a
trace_printk().

Once the buffers are allocated, they are never freed. If you use
a trace_printk() then you should know what you are doing.

A buffer is made for each type of context:

  normal
  softirq
  irq
  nmi

The context is checked and the appropriate buffer is used.
This allows for totally lockless usage of trace_printk(),
and they no longer even disable interrupts.
Requested-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      07d777fe
  27. 24 3月, 2012 2 次提交
  29. 21 3月, 2012 1 次提交
  31. 13 3月, 2012 1 次提交
  33. 05 3月, 2012 2 次提交
    • P
      kernel.h: doesn't explicitly use bug.h, so don't include it. · 6c03438e
      由 Paul Gortmaker 提交于 
      This header isn't using bug.h infrastructure, but due to historical
reasons, it was including it.  Removing it revealed several implicit
dependencies (since kernel.h is everywhere) so we've fixed those 1st
before deploying this change.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      6c03438e
    • P
      bug: consolidate BUILD_BUG_ON with other bug code · 35edd910
      由 Paul Gortmaker 提交于 
      The support for BUILD_BUG in linux/kernel.h predates the
addition of linux/bug.h -- with this chunk off separate,
you can run into situations where a person gets a compile
fail even when they've included linux/bug.h, like this:

    CC      lib/string.o
  lib/string.c: In function 'strlcat':
  lib/string.c:225:2: error: implicit declaration of function 'BUILD_BUG_ON'
  make[2]: *** [lib/string.o] Error 1
  $
  $ grep linux/bug.h lib/string.c
  #include <linux/bug.h>
  $

Since the above violates the principle of least surprise, move
the BUG chunks from kernel.h to bug.h so it is all together.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      35edd910
  35. 21 2月, 2012 1 次提交
  37. 13 1月, 2012 3 次提交
  39. 11 1月, 2012 1 次提交
    • D
      kernel.h: add BUILD_BUG() macro · 1399ff86
      由 David Daney 提交于 
      We can place this in definitions that we expect the compiler to remove by
dead code elimination.  If this assertion fails, we get a nice error
message at build time.

The GCC function attribute error("message") was added in version 4.3, so
we define a new macro __linktime_error(message) to expand to this for
GCC-4.3 and later.  This will give us an error diagnostic from the
compiler on the line that fails.  For other compilers
__linktime_error(message) expands to nothing, and we have to be content
with a link time error, but at least we will still get a build error.

BUILD_BUG() expands to the undefined function __build_bug_failed() and
will fail at link time if the compiler ever emits code for it.  On GCC-4.3
and later, attribute((error())) is used so that the failure will be noted
at compile time instead.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: DM <dm.n9107@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1399ff86
  41. 05 12月, 2011 1 次提交
  43. 07 11月, 2011 1 次提交
  45. 01 11月, 2011 3 次提交
  47. 21 9月, 2011 1 次提交
    • M
      lib: add error checking to hex2bin · b7804983
      由 Mimi Zohar 提交于 
      hex2bin converts a hexadecimal string to its binary representation.
The original version of hex2bin did not do any error checking.  This
patch adds error checking and returns the result.

Changelog v1:
- removed unpack_hex_byte()
- changed return code from boolean to int

Changelog:
- use the new unpack_hex_byte()
- add __must_check compiler option (Andy Shevchenko's suggestion)
- change function API to return error checking result
  (based on Tetsuo Handa's initial patch)
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
      b7804983
  49. 26 7月, 2011 3 次提交
  51. 23 6月, 2011 1 次提交
  53. 16 6月, 2011 1 次提交
  55. 25 5月, 2011 2 次提交
  57. 19 5月, 2011 1 次提交
    • S
      ftrace: Allow dynamically allocated function tracers · cdbe61bf
      由 Steven Rostedt 提交于 
      Now that functions may be selected individually, it only makes sense
that we should allow dynamically allocated trace structures to
be traced. This will allow perf to allocate a ftrace_ops structure
at runtime and use it to pick and choose which functions that
structure will trace.

Note, a dynamically allocated ftrace_ops will always be called
indirectly instead of being called directly from the mcount in
entry.S. This is because there's no safe way to prevent mcount
from being preempted before calling the function, unless we
modify every entry.S to do so (not likely). Thus, dynamically allocated
functions will now be called by the ftrace_ops_list_func() that
loops through the ops that are allocated if there are more than
one op allocated at a time. This loop is protected with a
preempt_disable.

To determine if an ftrace_ops structure is allocated or not, a new
util function was added to the kernel/extable.c called
core_kernel_data(), which returns 1 if the address is between
_sdata and _edata.

Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      cdbe61bf
  59. 23 3月, 2011 1 次提交
    • A
      kstrto*: converting strings to integers done (hopefully) right · 33ee3b2e
      由 Alexey Dobriyan 提交于 
      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: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      33ee3b2e