Commit Graph

601715 Commits

Author SHA1 Message Date
Andrey Smirnov
0a553cbabd rtc: rtctest: Change no IRQ detection for RTC_IRQP_SET
A call to ioctl(..., RTC_IRQP_SET, ...) should never result in
ENOTTY. All new style RTC drivers implement it and all of the old style
drivers return EINVAL when they don't support periodic IRQs.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-26 23:43:54 +02:00
Andrey Smirnov
519efa9805 rtc: rtctest: Change no IRQ detection for RTC_IRQP_READ
A call to ioctl(..., RTC_IRQP_READ, ...) should never result in
ENOTTY. All new style RTC drivers implement it and all of the old style
drivers return EINVAL when they don't support periodic IRQs.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-26 23:43:49 +02:00
Andrey Smirnov
cd26fca202 rtc: rtctest: Change alarm IRQ support detection
For old style drivers, call a call to ioctl(..., RTC_ALM_SET, ...):

    - char/ds1302.c will always return -EINVAL
    - char/genrtc.c: will always return -EINVAL
    - char/rtc.c will succeed regardless if IRQs are supported or not
    - char/efirtc.c will always return -EINVAL
    - input/misc/hp_sdc_rtc.c ... that ioctl code is a good lesson about
      ifdefing code out and punting implementation ... and it will
      always return -EINVAL

For new style rtc drivers, a call to ioctl(..., RTC_ALM_SET, ...) never
results in a call to __rtc_set_alarm, since struct rtc_wkalarm passed to
rtc_set_alarm has 'enabled' field set to 0. This means that
rtc->ops->set_alarm driver hook is never called in that ioctl. Since no
driver code interaction happens as a part of that call, using its
results to ascertain properties of the driver is not going to work. To
remedy this - use the result of RTC_AIE_ON to make the judgement.

This patch also changes ENOTTY to EINVAL as an error code value that
would tell us that IRQs are not supported. There are three reason for
this:

 - As mentioned above old style driver never returns ENOTTY for this
   ioctl

 - In it's code __rtc_set_alarm() returns -EINVAL if rtc->ops->set_alarm
   method is not provided by the driver, so one reason for change is to
   be consistent with that code path.

 - A call to ioctl(..., RTC_UIE_ON, ...) will result in a call to
   rtc_update_irq_enable() and then __rtc_set_alarm(), which, if IRQs
   are not supported by the driver, will result in a non-zero error
   code. Returning ENOTTY in that case would:

   	 a) Not be consistent with other codepaths of
   	 rtc_update_irq_enable, for example the check of
   	 rtc->uie_unsupported

	 b) Would break update IRQ emulation code since that codpath
	 expects EINVAL

	 c) Would break test's logic for feature support detection in
	 the case of RTC_UIE_ON ioctl

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-26 23:43:44 +02:00
Alexandre Belloni
cde0fe2acd rtc: rv8803: broaden workaround
The previous workaround may still fail as there are actually 4 retries to
be done to ensure the communication succeed. Also, some I2C adapter drivers
may return -EIO instead of -ENXIO.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-26 01:26:16 +02:00
Arnd Bergmann
d6faca40f4 rtc: move mc146818 helper functions out-of-line
The mc146818_get_time/mc146818_set_time functions are rather large
inline functions in a global header file and are used in several
drivers and in x86 specific code.

Here we move them into a separate .c file that is compiled whenever
any of the users require it. This also lets us remove the linux/acpi.h
header inclusion from mc146818rtc.h, which in turn avoids some
warnings about duplicate definition of the TRUE/FALSE macros.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-26 01:20:08 +02:00
Arnd Bergmann
5ee98ab3a8 mn10300: use RTC_DRV_CMOS instead of CONFIG_RTC
nn10300 has a dependency on mc146818_get_time/mc146818_set_time,
which we want to move from the mc146818rtc.h header into the
rtc subsystem, which in turn is not usable on mn10300.

This changes mn10300 to use the modern rtc-cmos driver instead
of the old RTC driver, and that in turn lets us completely
remove the read_persistent_clock/update_persistent_clock callbacks.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-26 01:20:08 +02:00
Arnd Bergmann
c361db5c2c x86: include linux/ratelimit.h in nmi.c
When building random configurations, we now occasionally get a new
build error:

   In file included from include/linux/kernel.h:13:0,
                    from include/linux/list.h:8,
                    from include/linux/preempt.h:10,
                    from include/linux/spinlock.h:50,
                    from arch/x86/kernel/nmi.c:13:
   arch/x86/kernel/nmi.c: In function 'nmi_max_handler':
   include/linux/printk.h:375:9: error: type defaults to 'int' in declaration of 'DEFINE_RATELIMIT_STATE' [-Werror=implicit-int]
     static DEFINE_RATELIMIT_STATE(_rs,    \
            ^
   arch/x86/kernel/nmi.c:110:2: note: in expansion of macro 'printk_ratelimited'
     printk_ratelimited(KERN_INFO
     ^~~~~~~~~~~~~~~~~~

This was working before the rtc rework series because linux/ratelimit.h
was included implictly through asm/mach_traps.h -> asm/mc146818rtc.h
-> linux/mc146818rtc.h -> linux/rtc.h -> linux/device.h.

We clearly shouldn't rely on this indirect inclusion, so this adds
an explicit #include in the file that needs it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Fixes: 5ab788d738 ("rtc: cmos: move mc146818rtc code out of asm-generic/rtc.h")
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-06 17:10:15 +02:00
Alexander Graf
7368c69c03 rtc: efi: Fail probing if RTC reads don't work
While the EFI spec mandates an RTC, not every implementation actually adheres
to that rule (or can adhere to it - some systems just don't have an RTC).

For those, we really don't want to probe the EFI RTC driver at all, because if
we do we'd get a non-functional driver that does nothing useful but only spills
our kernel log with warnings.

Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-06 17:07:33 +02:00
Venkat Prashanth B U
06776c8921 rtc: add support for Maxim max6916
Add support for Maxim max6916 RTC.

Signed-off-by: Venkat Prashanth B U <venkat.prashanth2498@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 16:05:59 +02:00
Martin Kepplinger
82df3e045d rtc: pcf2123: use sign_extend32() for sign extension
Use sign_extend32() instead of open coding sign extension.

Signed-off-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 15:50:44 +02:00
Heinrich Schuchardt
c5776dec8f rtc: ds1685: correct day of month checking
The day of month is checked in ds1685_rtc_read_alarm
and ds1685_rtc_set_alarm.

Multiple errors exist in the day of month check.

Operator ! has a higher priority than &&.
(!(mday >= 1) && (mday <= 31)) is false for mday == 32.

When verifying the day of month the binary and the BCD mode
have to be considered.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 15:46:08 +02:00
Colin Ian King
2b2f5ff00f rtc: interface: ignore expired timers when enqueuing new timers
This patch fixes a RTC wakealarm issue, namely, the event fires during
hibernate and is not cleared from the list, causing hwclock to block.

The current enqueuing does not trigger an alarm if any expired timers
already exist on the timerqueue. This can occur when a RTC wake alarm
is used to wake a machine out of hibernate and the resumed state has
old expired timers that have not been removed from the timer queue.
This fix skips over any expired timers and triggers an alarm if there
are no pending timers on the timerqueue. Note that the skipped expired
timer will get reaped later on, so there is no need to clean it up
immediately.

The issue can be reproduced by putting a machine into hibernate and
waking it with the RTC wakealarm.  Running the example RTC test program
from tools/testing/selftests/timers/rtctest.c after the hibernate will
block indefinitely.  With the fix, it no longer blocks after the
hibernate resume.

BugLink: http://bugs.launchpad.net/bugs/1333569

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 15:43:22 +02:00
Arnd Bergmann
279da1495d sparc32: remove stale RTC_PORT definition
sparc32:allmodconfig fails to build in next-20160602 as follows.

In file included from drivers/block/floppy.c:185:0:
include/linux/mc146818rtc.h: In function 'mc146818_is_updating':
include/linux/mc146818rtc.h:138:9: error: 'rtc_port' undeclared (first use in this function)
include/linux/mc146818rtc.h:138:9: note: each undeclared identifier is reported only once for each function it appears in
include/linux/mc146818rtc.h: In function 'mc146818_get_time':
include/linux/mc146818rtc.h:172:17: error: 'rtc_port' undeclared (first use in this function)
include/linux/mc146818rtc.h: In function 'mc146818_set_time':
include/linux/mc146818rtc.h:278:8: error: 'rtc_port' undeclared (first use in this function)
scripts/Makefile.build:295: recipe for target 'drivers/block/floppy.o' failed

The reason is a duplicate definition of the RTC_PORT macro. The
one in arch/sparc/include/asm/io_32.h was apparently used a long time
ago for the drivers/char/rtc.c driver that is not available on SPARC
any more, since we now select 'RTC_CLASS' unconditionally.

Removing the macro fixes the build problem, and for consistency,
this also removes the RTC_ALWAYS_BCD macro and the comment for both.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Fixes: fd09cc80165c ("rtc: cmos: move mc146818rtc code out of asm-generic/rtc.h")
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 15:43:15 +02:00
Arnd Bergmann
6705fdb34c char/genrtc: remove the rest of the driver
No architecture uses the genrtc driver any more, so let's kill it off
for good. This now also includes asm-generic/rtc.h, which is otherwise
completely unused.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:36 +02:00
Arnd Bergmann
f9a8097a83 char/genrtc: remove asm-generic/rtc.h from mips
arch/mips/sni/time.c includes asm-generic/rtc.h for no apparent reason,
and it works fine without that header, so lets remove the inclusion
in preparation of deleting the file.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:36 +02:00
Arnd Bergmann
4273b49a52 rtc: generic: remove get_rtc_time/set_rtc_time wrappers
All architectures using this driver are now converted to
provide their own operations, so this one can be turned
into a trivial stub driver relying on its platform data.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:35 +02:00
Arnd Bergmann
835ea93e9d char/genrtc: remove powerpc support
PowerPC is the last architecture using the GEN_RTC driver on some
machines, but we can migrate them all to using the RTC_DRV_GENERIC
driver instead now.

This moves over the CONFIG_GEN_RTC option from drivers/char into
arch/powerpc/platforms/Kconfig and makes it just select the
replacement driver instead, for the only reason of not breaking
existing defconfig and .config files that users may have.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:35 +02:00
Arnd Bergmann
169047f447 rtc: powerpc: provide rtc_class_ops directly
The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and powerpc has another abstraction on top, which is a bit
silly.

This changes the powerpc rtc-generic device to provide its
rtc_class_ops directly, to reduce the number of layers
by one.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:34 +02:00
Arnd Bergmann
084b3600e2 char/genrtc: remove m68k support
The asm/rtc.h header is only used for the old gen_rtc driver
that has been replaced by rtc-generic. According to Geert
Uytterhoeven, nobody has used the old driver on m68k for
a long time, so we can now just remove the header file
and disallow the driver in Kconfig.

All files that used to include asm/rtc.h are now changed so
they include the headers that were used implicitly through
asm/rtc.h.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:28 +02:00
Arnd Bergmann
598e8a1fb5 rtc: m68k: provide ioctl for q40
The q40 platform is the only machine in the kernel that provides
RTC_PLL_GET/RTC_PLL_SET ioctl commands in its rtc through the
mach_get_rtc_pll/mach_set_rtc_pll callbacks.

However, this currenctly works only in the old-style genrtc
driver, not the (somewhat) modern rtc-generic driver replacing
it. This adds an ioctl implementation to the m68k generic_rtc_ops
in order to let both drivers provide the same API.

After this, we should be able to remove support for genrtc
from the m68k architecture.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:22 +02:00
Arnd Bergmann
923c904c33 rtc: m68k: provide rtc_class_ops directly
The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and m68k has another abstraction on top, which is a bit
silly.

This changes the m68k rtc-generic device to provide its
rtc_class_ops directly, to reduce the number of layers
by one.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:05 +02:00
Arnd Bergmann
8bbe6b6f00 char/genrtc: remove parisc support
This architecture selects RTC_CLASS unconditionally, so the GEN_RTC
has not worked here for a long time.

Now we can remove both the asm/rtc.h header and the Kconfig dependency
for CONFIG_GEN_RTC.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:04 +02:00
Arnd Bergmann
ca6da80187 rtc: parisc: provide rtc_class_ops directly
The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and on pa-risc, that is implemented using an open-coded
version of rtc_time_to_tm/rtc_tm_to_time.

This changes the parisc rtc-generic device to provide its
rtc_class_ops directly, using the normal helper functions,
which makes this y2038 safe (on 32-bit) and simplifies
the implementation.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:04 +02:00
Arnd Bergmann
7ee942179f char/genrtc: remove mn10300 support
The genrtc driver serves no purpose on mn10300 because it drives the
same hardware as the original rtc.c driver, and the newer rtc-generic.c
or rtc-cmos.c drivers on architectures that use the asm-generic/rtc.h
header.

I assume it was initially only added for completeness when the
mn10300 port was done, but the older rtc.c driver was always used
instead.

We can also stop include asm-generic/rtc.h now, because we
just call mc146818_set_time() directly.

It would be nice to change the architecture to use the rtc-cmos driver
next, and remove support for the old rtc driver as well.

[linux@roeck-us.net: Add missing include file to proc-init.c]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:03 +02:00
Arnd Bergmann
1cb1e35327 char/genrtc: remove alpha support
The genrtc driver serves no purpose on Alpha because it drives the
same hardware as the original rtc.c driver, and the newer rtc-generic.c
or rtc-cmos.c drivers on architectures that use the asm-generic/rtc.h
header.

The defconfig uses CONFIG_RTC=y, so this driver is not used by default.
At one point it was used to abstract a quirk for the "Marvel" platform,
but it does not do this any more after the code was moved into yet
another driver in arch/alpha/kernel/rtc.c.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:23:02 +02:00
Arnd Bergmann
d4db68741d rtc: sh: provide rtc_class_ops directly
The rtc-generic driver provides an architecture specific
wrapper on top of the generic rtc_class_ops abstraction,
and on sh, that goes through another indirection using
the rtc_sh_get_time/rtc_sh_set_time functions.

This changes the sh rtc-generic device to provide its
rtc_class_ops directly, skipping one of the abstraction
levels.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rich Felker <dalias@libc.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:22:46 +02:00
Arnd Bergmann
463a86304c char/genrtc: x86: remove remnants of asm/rtc.h
Commit 3195ef59cb ("x86: Do full rtc synchronization with ntp") had
the side-effect of unconditionally enabling the RTC_LIB symbol on x86,
which in turn disables the selection of the CONFIG_RTC and
CONFIG_GEN_RTC drivers that contain a two older implementations of
the CONFIG_RTC_DRV_CMOS driver.

This removes x86 from the list for genrtc, and changes all references
to the asm/rtc.h header to instead point to the interfaces
from linux/mc146818rtc.h.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:20:07 +02:00
Arnd Bergmann
5ab788d738 rtc: cmos: move mc146818rtc code out of asm-generic/rtc.h
Drivers should not really include stuff from asm-generic directly,
and the PC-style cmos rtc driver does this in order to reuse the
mc146818 implementation of get_rtc_time/set_rtc_time rather than
the architecture specific one for the architecture it gets built for.

To make it more obvious what is going on, this moves and renames the
two functions into include/linux/mc146818rtc.h, which holds the
other mc146818 specific code. Ideally it would be in a .c file,
but that would require extra infrastructure as the functions are
called by multiple drivers with conflicting dependencies.

With this change, the asm-generic/rtc.h header also becomes much
more generic, so it can be reused more easily across any architecture
that still relies on the genrtc driver.

The only caller of the internal __get_rtc_time/__set_rtc_time
functions is in arch/alpha/kernel/rtc.c, and we just change those
over to the new naming.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:20:00 +02:00
Arnd Bergmann
f09c5142ee rtc: cmos: remove empty asm/mc146818rtc.h files
Nothing on these architectures ever includes the asm/mc146818rtc.h
file, the drivers that used to do this have been fixed long ago,
and the remaining users are all PC-specific.

This removes the files for good.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-06-04 00:19:04 +02:00
Geert Uytterhoeven
7af6a2e1c2 MAINTAINERS: Add file patterns for rtc device tree bindings
Submitters of device tree binding documentation may forget to CC
the subsystem maintainer if this is missing.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: rtc-linux@googlegroups.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-05-30 01:40:32 +02:00
Uwe Kleine-König
d68778b80d rtc: initialize output parameter for read alarm to "uninitialized"
rtc drivers are supposed to set values they don't support to -1. To
simplify this for drivers and also make it harder for them to get it
wrong initialize the values to -1.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-05-30 01:37:11 +02:00
Linus Torvalds
1a695a905c Linux 4.7-rc1 2016-05-29 09:29:24 -07:00
George Spelvin
e0ab7af9bd hash_string: Fix zero-length case for !DCACHE_WORD_ACCESS
The self-test was updated to cover zero-length strings; the function
needs to be updated, too.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Fixes: fcfd2fbf22 ("fs/namei.c: Add hashlen_string() function")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-29 07:33:47 -07:00
George Spelvin
f2a031b66e Rename other copy of hash_string to hashlen_string
The original name was simply hash_string(), but that conflicted with a
function with that name in drivers/base/power/trace.c, and I decided
that calling it "hashlen_" was better anyway.

But you have to do it in two places.

[ This caused build errors for architectures that don't define
  CONFIG_DCACHE_WORD_ACCESS   - Linus ]

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Fixes: fcfd2fbf22 ("fs/namei.c: Add hashlen_string() function")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 22:34:33 -07:00
Mikulas Patocka
037369b872 hpfs: implement the show_options method
The HPFS filesystem used generic_show_options to produce string that is
displayed in /proc/mounts.  However, there is a problem that the options
may disappear after remount.  If we mount the filesystem with option1
and then remount it with option2, /proc/mounts should show both option1
and option2, however it only shows option2 because the whole option
string is replaced with replace_mount_options in hpfs_remount_fs.

To fix this bug, implement the hpfs_show_options function that prints
options that are currently selected.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 16:50:24 -07:00
Mikulas Patocka
01d6e08711 affs: fix remount failure when there are no options changed
Commit c8f33d0bec ("affs: kstrdup() memory handling") checks if the
kstrdup function returns NULL due to out-of-memory condition.

However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL.  In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists.  The mount syscall then fails with
ENOMEM.

This patch fixes the bug.  We fail with ENOMEM only if data is non-NULL.

The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).

Fixes: c8f33d0bec ("affs: kstrdup() memory handling")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org	# v4.1+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 16:50:24 -07:00
Mikulas Patocka
44d51706b4 hpfs: fix remount failure when there are no options changed
Commit ce657611ba ("hpfs: kstrdup() out of memory handling") checks if
the kstrdup function returns NULL due to out-of-memory condition.

However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL.  In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists.  The mount syscall then fails with
ENOMEM.

This patch fixes the bug.  We fail with ENOMEM only if data is non-NULL.

The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).

Fixes: ce657611ba ("hpfs: kstrdup() out of memory handling")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 16:50:24 -07:00
Linus Torvalds
4029632c34 Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
Pull more MIPS updates from Ralf Baechle:
 "This is the secondnd batch of MIPS patches for 4.7. Summary:

  CPS:
   - Copy EVA configuration when starting secondary VPs.

  EIC:
   - Clear Status IPL.

  Lasat:
   - Fix a few off by one bugs.

  lib:
   - Mark intrinsics notrace.  Not only are the intrinsics
     uninteresting, it would cause infinite recursion.

  MAINTAINERS:
   - Add file patterns for MIPS BRCM device tree bindings.
   - Add file patterns for mips device tree bindings.

  MT7628:
   - Fix MT7628 pinmux typos.
   - wled_an pinmux gpio.
   - EPHY LEDs pinmux support.

  Pistachio:
   - Enable KASLR

  VDSO:
   - Build microMIPS VDSO for microMIPS kernels.
   - Fix aliasing warning by building with `-fno-strict-aliasing' for
     debugging but also tracing them might result in recursion.

  Misc:
   - Add missing FROZEN hotplug notifier transitions.
   - Fix clk binding example for varioius PIC32 devices.
   - Fix cpu interrupt controller node-names in the DT files.
   - Fix XPA CPU feature separation.
   - Fix write_gc0_* macros when writing zero.
   - Add inline asm encoding helpers.
   - Add missing VZ accessor microMIPS encodings.
   - Fix little endian microMIPS MSA encodings.
   - Add 64-bit HTW fields and fix its configuration.
   - Fix sigreturn via VDSO on microMIPS kernel.
   - Lots of typo fixes.
   - Add definitions of SegCtl registers and use them"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (49 commits)
  MIPS: Add missing FROZEN hotplug notifier transitions
  MIPS: Build microMIPS VDSO for microMIPS kernels
  MIPS: Fix sigreturn via VDSO on microMIPS kernel
  MIPS: devicetree: fix cpu interrupt controller node-names
  MIPS: VDSO: Build with `-fno-strict-aliasing'
  MIPS: Pistachio: Enable KASLR
  MIPS: lib: Mark intrinsics notrace
  MIPS: Fix 64-bit HTW configuration
  MIPS: Add 64-bit HTW fields
  MAINTAINERS: Add file patterns for mips device tree bindings
  MAINTAINERS: Add file patterns for mips brcm device tree bindings
  MIPS: Simplify DSP instruction encoding macros
  MIPS: Add missing tlbinvf/XPA microMIPS encodings
  MIPS: Fix little endian microMIPS MSA encodings
  MIPS: Add missing VZ accessor microMIPS encodings
  MIPS: Add inline asm encoding helpers
  MIPS: Spelling fix lets -> let's
  MIPS: VR41xx: Fix typo
  MIPS: oprofile: Fix typo
  MIPS: math-emu: Fix typo
  ...
2016-05-28 16:41:39 -07:00
Guenter Roeck
d66492bce1 fs: fix binfmt_aout.c build error
Various builds (such as i386:allmodconfig) fail with

  fs/binfmt_aout.c:133:2: error: expected identifier or '(' before 'return'
  fs/binfmt_aout.c:134:1: error: expected identifier or '(' before '}' token

[ Oops. My bad, I had stupidly thought that "allmodconfig" covered this
  on x86-64 too, but it obviously doesn't.  Egg on my face.  - Linus ]

Fixes: 5d22fc25d4 ("mm: remove more IS_ERR_VALUE abuses")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-28 16:34:59 -07:00
Linus Torvalds
7e0fb73c52 Merge branch 'hash' of git://ftp.sciencehorizons.net/linux
Pull string hash improvements from George Spelvin:
 "This series does several related things:

   - Makes the dcache hash (fs/namei.c) useful for general kernel use.

     (Thanks to Bruce for noticing the zero-length corner case)

   - Converts the string hashes in <linux/sunrpc/svcauth.h> to use the
     above.

   - Avoids 64-bit multiplies in hash_64() on 32-bit platforms.  Two
     32-bit multiplies will do well enough.

   - Rids the world of the bad hash multipliers in hash_32.

     This finishes the job started in commit 689de1d6ca ("Minimal
     fix-up of bad hashing behavior of hash_64()")

     The vast majority of Linux architectures have hardware support for
     32x32-bit multiply and so derive no benefit from "simplified"
     multipliers.

     The few processors that do not (68000, h8/300 and some models of
     Microblaze) have arch-specific implementations added.  Those
     patches are last in the series.

   - Overhauls the dcache hash mixing.

     The patch in commit 0fed3ac866 ("namei: Improve hash mixing if
     CONFIG_DCACHE_WORD_ACCESS") was an off-the-cuff suggestion.
     Replaced with a much more careful design that's simultaneously
     faster and better.  (My own invention, as there was noting suitable
     in the literature I could find.  Comments welcome!)

   - Modify the hash_name() loop to skip the initial HASH_MIX().  This
     would let us salt the hash if we ever wanted to.

   - Sort out partial_name_hash().

     The hash function is declared as using a long state, even though
     it's truncated to 32 bits at the end and the extra internal state
     contributes nothing to the result.  And some callers do odd things:

      - fs/hfs/string.c only allocates 32 bits of state
      - fs/hfsplus/unicode.c uses it to hash 16-bit unicode symbols not bytes

   - Modify bytemask_from_count to handle inputs of 1..sizeof(long)
     rather than 0..sizeof(long)-1.  This would simplify users other
     than full_name_hash"

  Special thanks to Bruce Fields for testing and finding bugs in v1.  (I
  learned some humbling lessons about "obviously correct" code.)

  On the arch-specific front, the m68k assembly has been tested in a
  standalone test harness, I've been in contact with the Microblaze
  maintainers who mostly don't care, as the hardware multiplier is never
  omitted in real-world applications, and I haven't heard anything from
  the H8/300 world"

* 'hash' of git://ftp.sciencehorizons.net/linux:
  h8300: Add <asm/hash.h>
  microblaze: Add <asm/hash.h>
  m68k: Add <asm/hash.h>
  <linux/hash.h>: Add support for architecture-specific functions
  fs/namei.c: Improve dcache hash function
  Eliminate bad hash multipliers from hash_32() and  hash_64()
  Change hash_64() return value to 32 bits
  <linux/sunrpc/svcauth.h>: Define hash_str() in terms of hashlen_string()
  fs/namei.c: Add hashlen_string() function
  Pull out string hash to <linux/stringhash.h>
2016-05-28 16:15:25 -07:00
George Spelvin
4684fe9530 h8300: Add <asm/hash.h>
This will improve the performance of hash_32() and hash_64(), but due
to complete lack of multi-bit shift instructions on H8, performance will
still be bad in surrounding code.

Designing H8-specific hash algorithms to work around that is a separate
project.  (But if the maintainers would like to get in touch...)

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
2016-05-28 15:48:58 -04:00
George Spelvin
7b13277b68 microblaze: Add <asm/hash.h>
Microblaze is an FPGA soft core that can be configured various ways.

If it is configured without a multiplier, the standard __hash_32()
will require a call to __mulsi3, which is a slow software loop.

Instead, use a shift-and-add sequence for the constant multiply.
GCC knows how to do this, but it's not as clever as some.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Alistair Francis <alistair.francis@xilinx.com>
Cc: Michal Simek <michal.simek@xilinx.com>
2016-05-28 15:48:58 -04:00
George Spelvin
14c44b95b3 m68k: Add <asm/hash.h>
This provides a multiply by constant GOLDEN_RATIO_32 = 0x61C88647
for the original mc68000, which lacks a 32x32-bit multiply instruction.

Yes, the amount of optimization effort put in is excessive. :-)

Shift-add chain found by Yevgen Voronenko's Hcub algorithm at
http://spiral.ece.cmu.edu/mcm/gen.html

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Philippe De Muyter <phdm@macq.eu>
Cc: linux-m68k@lists.linux-m68k.org
2016-05-28 15:48:57 -04:00
George Spelvin
468a942852 <linux/hash.h>: Add support for architecture-specific functions
This is just the infrastructure; there are no users yet.

This is modelled on CONFIG_ARCH_RANDOM; a CONFIG_ symbol declares
the existence of <asm/hash.h>.

That file may define its own versions of various functions, and define
HAVE_* symbols (no CONFIG_ prefix!) to suppress the generic ones.

Included is a self-test (in lib/test_hash.c) that verifies the basics.
It is NOT in general required that the arch-specific functions compute
the same thing as the generic, but if a HAVE_* symbol is defined with
the value 1, then equality is tested.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Philippe De Muyter <phdm@macq.eu>
Cc: linux-m68k@lists.linux-m68k.org
Cc: Alistair Francis <alistai@xilinx.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
2016-05-28 15:48:31 -04:00
George Spelvin
2a18da7a9c fs/namei.c: Improve dcache hash function
Patch 0fed3ac866 improved the hash mixing, but the function is slower
than necessary; there's a 7-instruction dependency chain (10 on x86)
each loop iteration.

Word-at-a-time access is a very tight loop (which is good, because
link_path_walk() is one of the hottest code paths in the entire kernel),
and the hash mixing function must not have a longer latency to avoid
slowing it down.

There do not appear to be any published fast hash functions that:
1) Operate on the input a word at a time, and
2) Don't need to know the length of the input beforehand, and
3) Have a single iterated mixing function, not needing conditional
   branches or unrolling to distinguish different loop iterations.

One of the algorithms which comes closest is Yann Collet's xxHash, but
that's two dependent multiplies per word, which is too much.

The key insights in this design are:

1) Barring expensive ops like multiplies, to diffuse one input bit
   across 64 bits of hash state takes at least log2(64) = 6 sequentially
   dependent instructions.  That is more cycles than we'd like.
2) An operation like "hash ^= hash << 13" requires a second temporary
   register anyway, and on a 2-operand machine like x86, it's three
   instructions.
3) A better use of a second register is to hold a two-word hash state.
   With careful design, no temporaries are needed at all, so it doesn't
   increase register pressure.  And this gets rid of register copying
   on 2-operand machines, so the code is smaller and faster.
4) Using two words of state weakens the requirement for one-round mixing;
   we now have two rounds of mixing before cancellation is possible.
5) A two-word hash state also allows operations on both halves to be
   done in parallel, so on a superscalar processor we get more mixing
   in fewer cycles.

I ended up using a mixing function inspired by the ChaCha and Speck
round functions.  It is 6 simple instructions and 3 cycles per iteration
(assuming multiply by 9 can be done by an "lea" instruction):

		x ^= *input++;
	y ^= x;	x = ROL(x, K1);
	x += y;	y = ROL(y, K2);
	y *= 9;

Not only is this reversible, two consecutive rounds are reversible:
if you are given the initial and final states, but not the intermediate
state, it is possible to compute both input words.  This means that at
least 3 words of input are required to create a collision.

(It also has the property, used by hash_name() to avoid a branch, that
it hashes all-zero to all-zero.)

The rotate constants K1 and K2 were found by experiment.  The search took
a sample of random initial states (I used 1023) and considered the effect
of flipping each of the 64 input bits on each of the 128 output bits two
rounds later.  Each of the 8192 pairs can be considered a biased coin, and
adding up the Shannon entropy of all of them produces a score.

The best-scoring shifts also did well in other tests (flipping bits in y,
trying 3 or 4 rounds of mixing, flipping all 64*63/2 pairs of input bits),
so the choice was made with the additional constraint that the sum of the
shifts is odd and not too close to the word size.

The final state is then folded into a 32-bit hash value by a less carefully
optimized multiply-based scheme.  This also has to be fast, as pathname
components tend to be short (the most common case is one iteration!), but
there's some room for latency, as there is a fair bit of intervening logic
before the hash value is used for anything.

(Performance verified with "bonnie++ -s 0 -n 1536:-2" on tmpfs.  I need
a better benchmark; the numbers seem to show a slight dip in performance
between 4.6.0 and this patch, but they're too noisy to quote.)

Special thanks to Bruce fields for diligent testing which uncovered a
nasty fencepost error in an earlier version of this patch.

[checkpatch.pl formatting complaints noted and respectfully disagreed with.]

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Tested-by: J. Bruce Fields <bfields@redhat.com>
2016-05-28 15:45:29 -04:00
George Spelvin
ef703f49a6 Eliminate bad hash multipliers from hash_32() and hash_64()
The "simplified" prime multipliers made very bad hash functions, so get rid
of them.  This completes the work of 689de1d6ca.

To avoid the inefficiency which was the motivation for the "simplified"
multipliers, hash_64() on 32-bit systems is changed to use a different
algorithm.  It makes two calls to hash_32() instead.

drivers/media/usb/dvb-usb-v2/af9015.c uses the old GOLDEN_RATIO_PRIME_32
for some horrible reason, so it inherits a copy of the old definition.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Antti Palosaari <crope@iki.fi>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
2016-05-28 15:42:51 -04:00
George Spelvin
92d567740f Change hash_64() return value to 32 bits
That's all that's ever asked for, and it makes the return
type of hash_long() consistent.

It also allows (upcoming patch) an optimized implementation
of hash_64 on 32-bit machines.

I tried adding a BUILD_BUG_ON to ensure the number of bits requested
was never more than 32 (most callers use a compile-time constant), but
adding <linux/bug.h> to <linux/hash.h> breaks the tools/perf compiler
unless tools/perf/MANIFEST is updated, and understanding that code base
well enough to update it is too much trouble.  I did the rest of an
allyesconfig build with such a check, and nothing tripped.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
2016-05-28 15:42:51 -04:00
George Spelvin
917ea166f4 <linux/sunrpc/svcauth.h>: Define hash_str() in terms of hashlen_string()
Finally, the first use of previous two patches: eliminate the
separate ad-hoc string hash functions in the sunrpc code.

Now hash_str() is a wrapper around hash_string(), and hash_mem() is
likewise a wrapper around full_name_hash().

Note that sunrpc code *does* call hash_mem() with a zero length, which
is why the previous patch needed to handle that in full_name_hash().
(Thanks, Bruce, for finding that!)

This also eliminates the only caller of hash_long which asks for
more than 32 bits of output.

The comment about the quality of hashlen_string() and full_name_hash()
is jumping the gun by a few patches; they aren't very impressive now,
but will be improved greatly later in the series.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: linux-nfs@vger.kernel.org
2016-05-28 15:42:50 -04:00
George Spelvin
fcfd2fbf22 fs/namei.c: Add hashlen_string() function
We'd like to make more use of the highly-optimized dcache hash functions
throughout the kernel, rather than have every subsystem create its own,
and a function that hashes basic null-terminated strings is required
for that.

(The name is to emphasize that it returns both hash and length.)

It's actually useful in the dcache itself, specifically d_alloc_name().
Other uses in the next patch.

full_name_hash() is also tweaked to make it more generally useful:
1) Take a "char *" rather than "unsigned char *" argument, to
   be consistent with hash_name().
2) Handle zero-length inputs.  If we want more callers, we don't want
   to make them worry about corner cases.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
2016-05-28 15:42:50 -04:00
George Spelvin
f4bcbe792b Pull out string hash to <linux/stringhash.h>
... so they can be used without the rest of <linux/dcache.h>

The hashlen_* macros will make sense next patch.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
2016-05-28 15:42:40 -04:00