Fix the kernel-doc markings for div64 functions to point to the header
file instead of the lib/ directory. This avoids having implementation
specific comments in generic documentation. Furthermore, given that
some kernel-doc comments are identical, drop them from lib/math64 and
only keep there comments that add implementation details.
Signed-off-by: Liam Beguin <[email protected]>
Acked-by: Randy Dunlap <[email protected]>
Tested-by: Randy Dunlap <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>
Patch series "math: RATIONAL and RATIONAL_KUNIT_TEST improvements".
This series makes the RATIONAL symbol tristate, so it is not forced
builtin if all users are modular, and makes the RATIONAL_KUNIT_TEST depend
on RATIONAL, to avoid enabling RATIONAL if there are no real users.
This patch (of 2):
All but one symbols that select RATIONAL are tristate, but RATIONAL itself
is bool. Change it to tristate, so the rational fractions support code
can be modular if no builtin code relies on it.
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Cc: Trent Piepho <[email protected]>
Cc: Colin Ian King <[email protected]>
Cc: Brendan Higgins <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
If the input is out of the range of the allowed values, either larger than
the largest value or closer to zero than the smallest non-zero allowed
value, then a division by zero would occur.
In the case of input too large, the division by zero will occur on the
first iteration. The best result (largest allowed value) will be found by
always choosing the semi-convergent and excluding the denominator based
limit when finding it.
In the case of the input too small, the division by zero will occur on the
second iteration. The numerator based semi-convergent should not be
calculated to avoid the division by zero. But the semi-convergent vs
previous convergent test is still needed, which effectively chooses
between 0 (the previous convergent) vs the smallest allowed fraction (best
semi-convergent) as the result.
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 323dd2c3ed ("lib/math/rational.c: fix possible incorrect result from rational fractions helper")
Signed-off-by: Trent Piepho <[email protected]>
Reported-by: Yiyuan Guo <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Cc: Oskar Schirmer <[email protected]>
Cc: Daniel Latypov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Pull MIPS updates from Thomas Bogendoerfer:
- removed get_fs/set_fs
- removed broken/unmaintained MIPS KVM trap and emulate support
- added support for Loongson-2K1000
- fixes and cleanups
* tag 'mips_5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (107 commits)
MIPS: BCM63XX: Use BUG_ON instead of condition followed by BUG.
MIPS: select ARCH_KEEP_MEMBLOCK unconditionally
mips: Do not include hi and lo in clobber list for R6
MIPS:DTS:Correct the license for Loongson-2K
MIPS:DTS:Fix label name and interrupt number of ohci for Loongson-2K
MIPS: Avoid handcoded DIVU in `__div64_32' altogether
lib/math/test_div64: Correct the spelling of "dividend"
lib/math/test_div64: Fix error message formatting
mips/bootinfo:correct some comments of fw_arg
MIPS: Avoid DIVU in `__div64_32' is result would be zero
MIPS: Reinstate platform `__div64_32' handler
div64: Correct inline documentation for `do_div'
lib/math: Add a `do_div' test module
MIPS: Makefile: Replace -pg with CC_FLAGS_FTRACE
MIPS: pci-legacy: revert "use generic pci_enable_resources"
MIPS: Loongson64: Add kexec/kdump support
MIPS: pci-legacy: use generic pci_enable_resources
MIPS: pci-legacy: remove busn_resource field
MIPS: pci-legacy: remove redundant info messages
MIPS: pci-legacy: stop using of_pci_range_to_resource
...
The word is spelt with a final "d" of course. What a massive messup!
Signed-off-by: Maciej W. Rozycki <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>
Align the expected result with one actually produced for easier visual
comparison; this has to take into account what the format specifiers
will actually produce rather than the characters they consist of. E.g.:
test_div64: ERROR: 10000000ab275080 / 00000009 => 01c71c71da20d00e,00000002
test_div64: ERROR: expected value => 0000000013045e47,00000001
(with a failure induced by setting bit #60 of the divident).
Signed-off-by: Maciej W. Rozycki <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>
Implement a module for correctness and performance evaluation for the
`do_div' function, often handled in an optimised manner by platform
code. Use a somewhat randomly generated set of inputs that is supposed
to be representative, using the same set of divisors twice, expressed as
a constant and as a variable each, so as to verify the implementation
for both cases should they be handled by different code execution paths.
Reference results were produced with GNU bc.
At the conclusion output the total execution time elapsed.
Signed-off-by: Maciej W. Rozycki <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>
kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out min()/max()
et al. helpers.
At the same time convert users in header and lib folder to use new header.
Though for time being include new header back to kernel.h to avoid
twisted indirected includes for other existing users.
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
People report that utime and stime from /proc/<pid>/stat become very
wrong when the numbers are big enough, especially if you watch these
counters incrementally.
Specifically, the current implementation of: stime*rtime/total,
results in a saw-tooth function on top of the desired line, where the
teeth grow in size the larger the values become. IOW, it has a
relative error.
The result is that, when watching incrementally as time progresses
(for large values), we'll see periods of pure stime or utime increase,
irrespective of the actual ratio we're striving for.
Replace scale_stime() with a math64.h helper: mul_u64_u64_div_u64()
that is far more accurate. This also allows architectures to override
the implementation -- for instance they can opt for the old algorithm
if this new one turns out to be too expensive for them.
Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Pull kselftest updates from Shuah Khan:
"This consists of:
- Several fixes from Masami Hiramatsu to improve coverage for lib and
sysctl tests.
- Clean up to vdso test and a new test for getcpu() from Mark Brown.
- Add new gen_tar selftests Makefile target generate selftest package
running "make gen_tar" in selftests directory from Veronika
Kabatova.
- Other miscellaneous fixes to timens, exec, tpm2 tests"
* tag 'linux-kselftest-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests/sysctl: Make sysctl test driver as a module
selftests/sysctl: Fix to load test_sysctl module
lib: Make test_sysctl initialized as module
lib: Make prime number generator independently selectable
selftests/ftrace: Return unsupported if no error_log file
selftests/ftrace: Use printf for backslash included command
selftests/timens: handle a case when alarm clocks are not supported
Kernel selftests: Add check if TPM devices are supported
selftests: vdso: Add a selftest for vDSO getcpu()
selftests: vdso: Use a header file to prototype parse_vdso API
selftests: vdso: Rename vdso_test to vdso_test_gettimeofday
selftests/exec: Verify execve of non-regular files fail
selftests: introduce gen_tar Makefile target
pr_xxx() functions usually have a newline at the end of the logging
message.
Here, this newline is added via the 'pr_fmt' macro.
In order to be more consistent with other files, use a more standard
convention and put these newlines back in the messages themselves and
remove it from the pr_fmt macro.
While at it, use __func__ instead of hardcoding a function name in the
last message.
Signed-off-by: Christophe JAILLET <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
Make prime number generator independently selectable from
kconfig. This allows us to enable CONFIG_PRIME_NUMBERS=m
and run the tools/testing/selftests/lib/prime_numbers.sh
without other DRM selftest modules.
Signed-off-by: Masami Hiramatsu <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>
Signed-off-by: Shuah Khan <[email protected]>
In some cases the previous algorithm would not return the closest
approximation. This would happen when a semi-convergent was the
closest, as the previous algorithm would only consider convergents.
As an example, consider an initial value of 5/4, and trying to find the
closest approximation with a maximum of 4 for numerator and denominator.
The previous algorithm would return 1/1 as the closest approximation,
while this version will return the correct answer of 4/3.
To do this, the main loop performs effectively the same operations as it
did before. It must now keep track of the last three approximations,
n2/d2 .. n0/d0, while before it only needed the last two.
If an exact answer is not found, the algorithm will now calculate the
best semi-convergent term, t, which is a single expression with two
divisions:
min((max_numerator - n0) / n1, (max_denominator - d0) / d1)
This will be used if it is better than previous convergent. The test
for this is generally a simple comparison, 2*t > a. But in an edge
case, where the convergent's final term is even and the best allowable
semi-convergent has a final term of exactly half the convergent's final
term, the more complex comparison (d0*dp > d1*d) is used.
I also wrote some comments explaining the code. While one still needs
to look up the math elsewhere, they should help a lot to follow how the
code relates to that math.
This routine is used in two places in the video4linux code, but in those
cases it is only used to reduce a fraction to lowest terms, which the
existing code will do correctly. This could be done more efficiently
with a different library routine but it would still be the Euclidean
alogrithm at its heart. So no change.
The remain users are places where a fractional PLL divider is
programmed. What would happen is something asked for a clock of X MHz
but instead gets Y MHz, where Y is close to X but not exactly due to the
hardware limitations. After this change they might, in some cases, get
Y' MHz, where Y' is a little closer to X then Y was.
Users like this are: Three UARTs, in 8250_mid, 8250_lpss, and imx. One
GPU in vp4_hdmi. And three clock drivers, clk-cdce706, clk-si5351, and
clk-fractional-divider. The last is a generic clock driver and so would
have more users referenced via device tree entries.
I think there's a bug in that one, it's limiting an N bit field that is
offset-by-1 to the range 0 .. (1<<N)-2, when it should be (1<<N)-1 as
the upper limit.
I have an IMX system, one of the UARTs using this, so I can provide a
real example. If I request a custom baud rate of 1499978, the driver
will program the PLL to produce a baud rate of 1500000. After this
change, the fractional divider in the UART is programmed to a ratio of
65535/65536, which produces a baud rate of 1499977.0625. Closer to the
requested value.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Trent Piepho <[email protected]>
Cc: Oskar Schirmer <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have MODULE_LICENCE("GPL*") inside which was used in the initial
scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Liam Beguin