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Add documentation for the ingenic-battery driver, used on JZ47xx SoCs.
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Merge immutable branch containing the IIO changes required
for the new Ingenic JZ47xx battery fuel gauge driver.
Signed-off-by: Sebastian Reichel <sre@kernel.org>
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This adds support for AXP813 PMIC. It is almost the same as AXP22X but
has a different current limit.
Signed-off-by: Quentin Schulz <quentin.schulz@bootlin.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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To prepare for a new PMIC, factor out the code responsible of returning
the maximum current to axp20x_get_current_max.
Signed-off-by: Quentin Schulz <quentin.schulz@bootlin.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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On AXP221 and later AXP PMICs that have the N_VBUSEN pin, when this pin
is high, either due to the PMIC driving it high or as an input, the VBUS
detection related interrupt mechanisms are disabled.
Previously this was worked around in the phy-sun4i-usb driver, which
needed to sense VBUS changes and report them to the musb driver in a
timely matter. However this workaround was only for the A31 and A33 type
USB PHYs. To support newer platforms we would have to enable it for
almost all the post-A31 SoCs.
However, since this is actually the result of the PMIC's behavior, the
workaround would be better if done in the PMIC driver, in this case the
VBUS power supply driver.
Add the same workqueue-based polling to the VBUS power supply driver.
The polling interval is chosen to be the debounce interval from the USB
PHY driver, as this short interval is needed in some cases, but the
power supply driver would not know when.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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The VBUS current limit value macros have VBUS typed as VBUC, while
the bitmask macro is named correctly. Fix it.
Fixes: 69fb4dcada77 ("power: Add an axp20x-usb-power driver")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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This adds the "x-powers,axp813-usb-power-supply" to the list of
compatibles for AXP20X VBUS power supply driver.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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The call to of_parse_phandle returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.
Detected by coccinelle with the following warnings:
./drivers/power/supply/power_supply_core.c:601:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 595, but without a corresponding object release within this function.
./drivers/power/supply/power_supply_core.c:604:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 595, but without a corresponding object release within this function.
./drivers/power/supply/power_supply_core.c:632:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 595, but without a corresponding object release within this function.
./drivers/power/supply/power_supply_core.c:635:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 595, but without a corresponding object release within this function.
./drivers/power/supply/power_supply_core.c:653:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 595, but without a corresponding object release within this function.
./drivers/power/supply/power_supply_core.c:664:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 595, but without a corresponding object release within this function.
./drivers/power/supply/power_supply_core.c:673:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 595, but without a corresponding object release within this function.
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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The call to of_parse_phandle returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.
492 int ab8500_bm_of_probe(struct device *dev,
493 struct device_node *np,
494 struct abx500_bm_data *bm)
495 {
496 const struct batres_vs_temp *tmp_batres_tbl;
497 struct device_node *battery_node;
...
501 /* get phandle to 'battery-info' node */
502 battery_node = of_parse_phandle(np, "battery", 0);
...
509 if (!btech) {
510 dev_warn(dev, "missing property battery-name/type\n");
511 return -EINVAL; ---> leaked here
512 }
...
540 of_node_put(battery_node); ---> released here
541
542 return 0;
543 }
Detected by coccinelle with the following warnings:
./drivers/power/supply/ab8500_bmdata.c:511:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 502, but without a corresponding object release within this function.
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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With loadable modules we may get the following during init:
could not initialize VBUS or ID IIO: -517
Let's not print any pointless error messages for deferred probe.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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With loadable modules we may get the following during init:
could not initialize VBUS or ID IIO: -517
Let's not print any pointless error messages for deferred probe.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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We should not use measured current value for average since we have proper
coulomb counter values available. Using measured current value should
be only used when the value is queried at a higher rate than the 250 ms
rate the coulomb counter is configured to run at.
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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The coulomb counter calibration is not CCO, it's CCM. And the CCM is
nine bits wide signed register, so let's use sign_extend32() for it.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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The accumulator sample register is signed 32-bits wide register on
droid 4. And only the earlier version of cpcap has a signed 24-bits
wide register. We're currently passing it around as unsigned, so
let's fix that and use sign_extend32() for the earlier revision.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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We need to check current instead of the charge counter to see if
a charger is connected. The charge counter shows the cumulated value
instead of the current charge current and can be negative or positive.
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Merge fixes branch into next branch for cpcap-battery
patches.
Signed-off-by: Sebastian Reichel <sre@collabora.com>
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Introduce optional support of POWER_SUPPLY_PROP_STATUS for chargers
which provide charging status GPIO.
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Add documentation for the "charge-status-gpios" property.
Update the "gpios" property with a valid example.
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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There is a spelling mistake in ps_get_cur_charge_cntl_limit function so
replace 'chrage' for 'charge'.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Convert "iio_read_avail_channel_raw" over to a wrapper around
"iio_read_avail_channel_attribute".
With the introduction of "iio_read_avail_channel_attribute",
the necessity of having a separate call to read raw channel values
became redundant.
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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Extend the inkern API with a function for reading available
attribute values of iio channels.
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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If called fast enough so samples do not increment, we can get
division by zero in kernel:
__div0
cpcap_battery_cc_raw_div
cpcap_battery_get_property
power_supply_get_property.part.1
power_supply_get_property
power_supply_show_property
power_supply_uevent
Fixes: 874b2adbed12 ("power: supply: cpcap-battery: Add a battery driver")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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rename only - no functional changes
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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There never was a device called LTC3651, it always was just LT3651.
This circumstance makes it pretty difficult to identify what this
driver is meant to control.channges since
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Explicitly cancel/sync the irq_work delayed work, otherwise
there's a chance that it will run after the device is removed,
which would result in a use-after-free.
Note that cancel/sync should happen:
- after irq's have been disabled, as the isr re-schedules the work
- before the power supply is unregistered, because the work func
uses the power supply handle.
Cc: Alexander Kurz <akurz@blala.de>
Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Call order on probe():
- max14656_hw_init() enables interrupts on the chip
- devm_request_irq() starts processing interrupts, isr
could be called immediately
- isr: schedules delayed work (irq_work)
- irq_work: calls power_supply_changed()
- devm_power_supply_register() registers the power supply
Depending on timing, it's possible that power_supply_changed()
is called on an unregistered power supply structure.
Fix by registering the power supply before requesting the irq.
Cc: Alexander Kurz <akurz@blala.de>
Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Add documentation for SAM9X60 shutdown controller.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Add support for SAM9X60 shutdown controller.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Add RTT wakeup capability.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Fix the example documentation which is missing a semi-colon.
Signed-off-by: Sebastien Bourdelin <sebastien.bourdelin@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Currently there is no check on platform_get_irq() return value
in case it fails, hence never actually reporting any errors and
causing unexpected behavior when using such value as argument
for function regmap_irq_get_virq().
Fix this by adding a proper check, a message reporting any errors
and returning *pirq*
Addresses-Coverity-ID: 1443940 ("Improper use of negative value")
Fixes: 843735b788a4 ("power: axp288_charger: axp288 charger driver")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Commit c08b1f45d7d1 ("power: supply: core: Add power_supply_battery_info
and API") introduced code to parse the simple-battery node and express
battery charging constraints. However, it parsed that node using the
properties constant_charge_current_max_microamp and
constant_charge_voltage_max_microvolt, while the device tree binding for
the simple-battery node uses dashes to separate the words in those
properties (constant-charge-current-max-microamp and
constant-charge-voltage-max-microvolt).
Let's make the code match the binding.
Fixes: c08b1f45d7d1 ("power: supply: core: Add power_supply_battery_info and API")
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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In case create_freezable_workqueue fails, the fix return -ENOMEM
to avoid a potential NULL pointer dereference.
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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Make the syscon-reboot driver accept value and mask instead of
just value.
Prior to this patch, the property name for the value was 'mask'. If
only the mask property is defined on a node, maintain compatibility
by using it as the value.
This patch is based on commit
f2c199db477e ("power: reset: syscon-poweroff: add a mask property")
and does the same change for the syscon-reboot driver.
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull more Kbuild updates from Masahiro Yamada:
- add more Build-Depends to Debian source package
- prefix header search paths with $(srctree)/
- make modpost show verbose section mismatch warnings
- avoid hard-coded CROSS_COMPILE for h8300
- fix regression for Debian make-kpkg command
- add semantic patch to detect missing put_device()
- fix some warnings of 'make deb-pkg'
- optimize NOSTDINC_FLAGS evaluation
- add warnings about redundant generic-y
- clean up Makefiles and scripts
* tag 'kbuild-v5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: remove stale lxdialog/.gitignore
kbuild: force all architectures except um to include mandatory-y
kbuild: warn redundant generic-y
Revert "modsign: Abort modules_install when signing fails"
kbuild: Make NOSTDINC_FLAGS a simply expanded variable
kbuild: deb-pkg: avoid implicit effects
coccinelle: semantic code search for missing put_device()
kbuild: pkg: grep include/config/auto.conf instead of $KCONFIG_CONFIG
kbuild: deb-pkg: introduce is_enabled and if_enabled_echo to builddeb
kbuild: deb-pkg: add CONFIG_ prefix to kernel config options
kbuild: add workaround for Debian make-kpkg
kbuild: source include/config/auto.conf instead of ${KCONFIG_CONFIG}
unicore32: simplify linker script generation for decompressor
h8300: use cc-cross-prefix instead of hardcoding h8300-unknown-linux-
kbuild: move archive command to scripts/Makefile.lib
modpost: always show verbose warning for section mismatch
ia64: prefix header search path with $(srctree)/
libfdt: prefix header search paths with $(srctree)/
deb-pkg: generate correct build dependencies
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Thomas Gleixner:
"Two cleanup patches removing dead conditionals and unused code"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/asm: Remove unused __constant_c_x_memset() macro and inlines
x86/asm: Remove dead __GNUC__ conditionals
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Thomas Gleixner:
"Three fixes for the fallout from the TSX errata workaround:
- Prevent memory corruption caused by a unchecked out of bound array
index.
- Two trivial fixes to address compiler warnings"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Make dev_attr_allow_tsx_force_abort static
perf/x86: Fixup typo in stub functions
perf/x86/intel: Fix memory corruption
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fix from Juergen Gross:
"A fix for a Xen bug introduced by David's series for excluding
ballooned pages in vmcores"
* tag 'for-linus-5.1b-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/balloon: Fix mapping PG_offline pages to user space
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Pull 9p updates from Dominique Martinet:
"Here is a 9p update for 5.1; there honestly hasn't been much.
Two fixes (leak on invalid mount argument and possible deadlock on
i_size update on 32bit smp) and a fall-through warning cleanup"
* tag '9p-for-5.1' of git://github.com/martinetd/linux:
9p/net: fix memory leak in p9_client_create
9p: use inode->i_lock to protect i_size_write() under 32-bit
9p: mark expected switch fall-through
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Fixes: 400816f60c54 ("perf/x86/intel: Implement support for TSX Force Abort")
Signed-off-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: kbuild-all@01.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190313184243.GA10820@lkp-sb-ep06
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When this .gitignore was added, lxdialog was an independent hostprogs-y.
Now that all objects in lxdialog/ are directly linked to mconf, the
lxdialog is no longer generated.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Currently, every arch/*/include/uapi/asm/Kbuild explicitly includes
the common Kbuild.asm file. Factor out the duplicated include directives
to scripts/Makefile.asm-generic so that no architecture would opt out
of the mandatory-y mechanism.
um is not forced to include mandatory-y since it is a very exceptional
case which does not support UAPI.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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The generic-y is redundant under the following condition:
- arch has its own implementation
- the same header is added to generated-y
- the same header is added to mandatory-y
If a redundant generic-y is found, the warning like follows is displayed:
scripts/Makefile.asm-generic:20: redundant generic-y found in arch/arm/include/asm/Kbuild: timex.h
I fixed up arch Kbuild files found by this.
Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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This reverts commit caf6fe91ddf62a96401e21e9b7a07227440f4185.
The commit was fine but is no longer needed as of commit 3a2429e1faf4
("kbuild: change if_changed_rule for multi-line recipe"). Let's go
back to using ";" to be consistent.
For some discussion, see:
https://lkml.kernel.org/r/CAK7LNASde0Q9S5GKeQiWhArfER4S4wL1=R_FW8q0++_X3T5=hQ@mail.gmail.com
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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During a simple no-op (nothing changed) build I saw 39 invocations of
the C compiler with the argument "-print-file-name=include". We don't
need to call the C compiler 39 times for this--one time will suffice.
Let's change NOSTDINC_FLAGS to a simply expanded variable to avoid
this since there doesn't appear to be any reason it should be
recursively expanded.
On my build this shaved ~400 ms off my "no-op" build.
Note that the recursive expansion seems to date back to the (really
old) commit e8f5bdb02ce0 ("[PATCH] Makefile include path ordering").
It's a little unclear to me if the point of that patch was to switch
the variable to be recursively expanded (which it did) or to avoid
directly assigning to NOSTDINC_FLAGS (AKA to switch to +=) because
someone else (out of tree?) was setting it. I presume later since if
the only goal was to switch to recursive expansion the patch would
have just removed the ":".
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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* The man page for dpkg-source(1) notes:
> -b, --build directory [format-specific-parameters]
> Build a source package (--build since dpkg 1.17.14).
> <...>
>
> dpkg-source will build the source package with the first
> format found in this ordered list: the format indicated
> with the --format command line option, the format
> indicated in debian/source/format, “1.0”. The fallback
> to “1.0” is deprecated and will be removed at some point
> in the future, you should always document the desired
> source format in debian/source/format. See section
> SOURCE PACKAGE FORMATS for an extensive description of
> the various source package formats.
Thus it would be more foolproof to explicitly use 1.0 (as we always
did) than to rely on dpkg-source's defaults.
* In a similar vein, debian/rules is not made executable by mkdebian,
and dpkg-source warns about that but still silently fixes the file.
Let's be explicit once again.
Signed-off-by: Arseny Maslennikov <ar@cs.msu.ru>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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The of_find_device_by_node() takes a reference to the underlying device
structure, we should release that reference.
The implementation of this semantic code search is:
In a function, for a local variable returned by calling
of_find_device_by_node(),
a, if it is released by a function such as
put_device()/of_dev_put()/platform_device_put() after the last use,
it is considered that there is no reference leak;
b, if it is passed back to the caller via
dev_get_drvdata()/platform_get_drvdata()/get_device(), etc., the
reference will be released in other functions, and the current function
also considers that there is no reference leak;
c, for the rest of the situation, the current function should release the
reference by calling put_device, this code search will report the
corresponding error message.
By using this semantic code search, we have found some object reference leaks,
such as:
commit 11907e9d3533 ("ASoC: fsl-asoc-card: fix object reference leaks in
fsl_asoc_card_probe")
commit a12085d13997 ("mtd: rawnand: atmel: fix possible object reference leak")
commit 11493f26856a ("mtd: rawnand: jz4780: fix possible object reference leak")
There are still dozens of reference leaks in the current kernel code.
Further, for the case of b, the object returned to other functions may also
have a reference leak, we will continue to develop other cocci scripts to
further check the reference leak.
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Reviewed-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Markus Elfring <Markus.Elfring@web.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull pidfd system call from Christian Brauner:
"This introduces the ability to use file descriptors from /proc/<pid>/
as stable handles on struct pid. Even if a pid is recycled the handle
will not change. For a start these fds can be used to send signals to
the processes they refer to.
With the ability to use /proc/<pid> fds as stable handles on struct
pid we can fix a long-standing issue where after a process has exited
its pid can be reused by another process. If a caller sends a signal
to a reused pid it will end up signaling the wrong process.
With this patchset we enable a variety of use cases. One obvious
example is that we can now safely delegate an important part of
process management - sending signals - to processes other than the
parent of a given process by sending file descriptors around via scm
rights and not fearing that the given process will have been recycled
in the meantime. It also allows for easy testing whether a given
process is still alive or not by sending signal 0 to a pidfd which is
quite handy.
There has been some interest in this feature e.g. from systems
management (systemd, glibc) and container managers. I have requested
and gotten comments from glibc to make sure that this syscall is
suitable for their needs as well. In the future I expect it to take on
most other pid-based signal syscalls. But such features are left for
the future once they are needed.
This has been sitting in linux-next for quite a while and has not
caused any issues. It comes with selftests which verify basic
functionality and also test that a recycled pid cannot be signaled via
a pidfd.
Jon has written about a prior version of this patchset. It should
cover the basic functionality since not a lot has changed since then:
https://lwn.net/Articles/773459/
The commit message for the syscall itself is extensively documenting
the syscall, including it's functionality and extensibility"
* tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
selftests: add tests for pidfd_send_signal()
signal: add pidfd_send_signal() syscall
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git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull device-dax updates from Dan Williams:
"New device-dax infrastructure to allow persistent memory and other
"reserved" / performance differentiated memories, to be assigned to
the core-mm as "System RAM".
Some users want to use persistent memory as additional volatile
memory. They are willing to cope with potential performance
differences, for example between DRAM and 3D Xpoint, and want to use
typical Linux memory management apis rather than a userspace memory
allocator layered over an mmap() of a dax file. The administration
model is to decide how much Persistent Memory (pmem) to use as System
RAM, create a device-dax-mode namespace of that size, and then assign
it to the core-mm. The rationale for device-dax is that it is a
generic memory-mapping driver that can be layered over any "special
purpose" memory, not just pmem. On subsequent boots udev rules can be
used to restore the memory assignment.
One implication of using pmem as RAM is that mlock() no longer keeps
data off persistent media. For this reason it is recommended to enable
NVDIMM Security (previously merged for 5.0) to encrypt pmem contents
at rest. We considered making this recommendation an actively enforced
requirement, but in the end decided to leave it as a distribution /
administrator policy to allow for emulation and test environments that
lack security capable NVDIMMs.
Summary:
- Replace the /sys/class/dax device model with /sys/bus/dax, and
include a compat driver so distributions can opt-in to the new ABI.
- Allow for an alternative driver for the device-dax address-range
- Introduce the 'kmem' driver to hotplug / assign a device-dax
address-range to the core-mm.
- Arrange for the device-dax target-node to be onlined so that the
newly added memory range can be uniquely referenced by numa apis"
NOTE! I'm not entirely happy with the whole "PMEM as RAM" model because
we currently have special - and very annoying rules in the kernel about
accessing PMEM only with the "MC safe" accessors, because machine checks
inside the regular repeat string copy functions can be fatal in some
(not described) circumstances.
And apparently the PMEM modules can cause that a lot more than regular
RAM. The argument is that this happens because PMEM doesn't necessarily
get scrubbed at boot like RAM does, but that is planned to be added for
the user space tooling.
Quoting Dan from another email:
"The exposure can be reduced in the volatile-RAM case by scanning for
and clearing errors before it is onlined as RAM. The userspace tooling
for that can be in place before v5.1-final. There's also runtime
notifications of errors via acpi_nfit_uc_error_notify() from
background scrubbers on the DIMM devices. With that mechanism the
kernel could proactively clear newly discovered poison in the volatile
case, but that would be additional development more suitable for v5.2.
I understand the concern, and the need to highlight this issue by
tapping the brakes on feature development, but I don't see PMEM as RAM
making the situation worse when the exposure is also there via DAX in
the PMEM case. Volatile-RAM is arguably a safer use case since it's
possible to repair pages where the persistent case needs active
application coordination"
* tag 'devdax-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
device-dax: "Hotplug" persistent memory for use like normal RAM
mm/resource: Let walk_system_ram_range() search child resources
mm/memory-hotplug: Allow memory resources to be children
mm/resource: Move HMM pr_debug() deeper into resource code
mm/resource: Return real error codes from walk failures
device-dax: Add a 'modalias' attribute to DAX 'bus' devices
device-dax: Add a 'target_node' attribute
device-dax: Auto-bind device after successful new_id
acpi/nfit, device-dax: Identify differentiated memory with a unique numa-node
device-dax: Add /sys/class/dax backwards compatibility
device-dax: Add support for a dax override driver
device-dax: Move resource pinning+mapping into the common driver
device-dax: Introduce bus + driver model
device-dax: Start defining a dax bus model
device-dax: Remove multi-resource infrastructure
device-dax: Kill dax_region base
device-dax: Kill dax_region ida
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