From: "Winiarska, Iwona" <iwona.winiarska@intel.com> To: "Williams, Dan J" <dan.j.williams@intel.com> Cc: "linux-aspeed@lists.ozlabs.org" <linux-aspeed@lists.ozlabs.org>, "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>, "zweiss@equinix.com" <zweiss@equinix.com>, "jae.hyun.yoo@linux.intel.com" <jae.hyun.yoo@linux.intel.com>, "andriy.shevchenko@linux.intel.com" <andriy.shevchenko@linux.intel.com>, "corbet@lwn.net" <corbet@lwn.net>, "openbmc@lists.ozlabs.org" <openbmc@lists.ozlabs.org>, "x86@kernel.org" <x86@kernel.org>, "pierre-louis.bossart@linux.intel.com" <pierre-louis.bossart@linux.intel.com>, "mingo@redhat.com" <mingo@redhat.com>, "linux@roeck-us.net" <linux@roeck-us.net>, "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, "jdelvare@suse.com" <jdelvare@suse.com>, "arnd@arndb.de" <arnd@arndb.de>, "robh+dt@kernel.org" <robh+dt@kernel.org>, "bp@alien8.de" <bp@alien8.de>, "Lutomirski, Andy" <luto@kernel.org>, "tglx@linutronix.de" <tglx@linutronix.de>, "mchehab@kernel.org" <mchehab@kernel.org>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "linux-hwmon@vger.kernel.org" <linux-hwmon@vger.kernel.org>, "Luck, Tony" <tony.luck@intel.com>, "andrew@aj.id.au" <andrew@aj.id.au>, "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>, "rdunlap@infradead.org" <rdunlap@infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "yazen.ghannam@amd.com" <yazen.ghannam@amd.com>, "olof@lixom.net" <olof@lixom.net> Subject: Re: [PATCH v2 09/15] peci: Add sysfs interface for PECI bus Date: Mon, 15 Nov 2021 22:19:04 +0000 [thread overview] Message-ID: <0fb36e270cd497ade90eb0a4e9882819af3472dd.camel@intel.com> (raw) In-Reply-To: <CAPcyv4hhtTi+dKspjoamYj53GxT4Ot_1pG5-eavUJdihD8iAEg@mail.gmail.com> On Fri, 2021-08-27 at 12:11 -0700, Dan Williams wrote: > On Tue, Aug 3, 2021 at 4:35 AM Iwona Winiarska > <iwona.winiarska@intel.com> wrote: > > > > PECI devices may not be discoverable at the time when PECI controller is > > being added (e.g. BMC can boot up when the Host system is still in S5). > > Since we currently don't have the capabilities to figure out the Host > > system state inside the PECI subsystem itself, we have to rely on > > userspace to do it for us. > > > > In the future, PECI subsystem may be expanded with mechanisms that allow > > us to avoid depending on userspace interaction (e.g. CPU presence could > > be detected using GPIO, and the information on whether it's discoverable > > could be obtained over IPMI). > > Thanks for this detail. > > > Unfortunately, those methods may ultimately not be available (support > > will vary from platform to platform), which means that we still need > > platform independent method triggered by userspace. > > > > Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com> > > --- > > Documentation/ABI/testing/sysfs-bus-peci | 16 +++++ > > drivers/peci/Makefile | 2 +- > > drivers/peci/core.c | 3 +- > > drivers/peci/device.c | 1 + > > drivers/peci/internal.h | 5 ++ > > drivers/peci/sysfs.c | 82 ++++++++++++++++++++++++ > > 6 files changed, 107 insertions(+), 2 deletions(-) > > create mode 100644 Documentation/ABI/testing/sysfs-bus-peci > > create mode 100644 drivers/peci/sysfs.c > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-peci > > b/Documentation/ABI/testing/sysfs-bus-peci > > new file mode 100644 > > index 000000000000..56c2b2216bbd > > --- /dev/null > > +++ b/Documentation/ABI/testing/sysfs-bus-peci > > @@ -0,0 +1,16 @@ > > +What: /sys/bus/peci/rescan > > +Date: July 2021 > > +KernelVersion: 5.15 > > +Contact: Iwona Winiarska <iwona.winiarska@intel.com> > > +Description: > > + Writing a non-zero value to this attribute will > > + initiate scan for PECI devices on all PECI controllers > > + in the system. > > + > > +What: /sys/bus/peci/devices/<controller_id>-<device_addr>/remove > > +Date: July 2021 > > +KernelVersion: 5.15 > > +Contact: Iwona Winiarska <iwona.winiarska@intel.com> > > +Description: > > + Writing a non-zero value to this attribute will > > + remove the PECI device and any of its children. > > diff --git a/drivers/peci/Makefile b/drivers/peci/Makefile > > index c5f9d3fe21bb..917f689e147a 100644 > > --- a/drivers/peci/Makefile > > +++ b/drivers/peci/Makefile > > @@ -1,7 +1,7 @@ > > # SPDX-License-Identifier: GPL-2.0-only > > > > # Core functionality > > -peci-y := core.o request.o device.o > > +peci-y := core.o request.o device.o sysfs.o > > obj-$(CONFIG_PECI) += peci.o > > > > # Hardware specific bus drivers > > diff --git a/drivers/peci/core.c b/drivers/peci/core.c > > index d143f1a7fe98..c473acb3c2a0 100644 > > --- a/drivers/peci/core.c > > +++ b/drivers/peci/core.c > > @@ -34,7 +34,7 @@ struct device_type peci_controller_type = { > > .release = peci_controller_dev_release, > > }; > > > > -static int peci_controller_scan_devices(struct peci_controller *controller) > > +int peci_controller_scan_devices(struct peci_controller *controller) > > { > > int ret; > > u8 addr; > > @@ -159,6 +159,7 @@ EXPORT_SYMBOL_NS_GPL(devm_peci_controller_add, PECI); > > > > struct bus_type peci_bus_type = { > > .name = "peci", > > + .bus_groups = peci_bus_groups, > > }; > > > > static int __init peci_init(void) > > diff --git a/drivers/peci/device.c b/drivers/peci/device.c > > index 32811248997b..d77d9dabd51e 100644 > > --- a/drivers/peci/device.c > > +++ b/drivers/peci/device.c > > @@ -110,5 +110,6 @@ static void peci_device_release(struct device *dev) > > } > > > > struct device_type peci_device_type = { > > + .groups = peci_device_groups, > > .release = peci_device_release, > > }; > > diff --git a/drivers/peci/internal.h b/drivers/peci/internal.h > > index 57d11a902c5d..978e12c8e1d3 100644 > > --- a/drivers/peci/internal.h > > +++ b/drivers/peci/internal.h > > @@ -8,6 +8,7 @@ > > #include <linux/types.h> > > > > struct peci_controller; > > +struct attribute_group; > > struct peci_device; > > struct peci_request; > > > > @@ -19,12 +20,16 @@ struct peci_request *peci_request_alloc(struct > > peci_device *device, u8 tx_len, u > > void peci_request_free(struct peci_request *req); > > > > extern struct device_type peci_device_type; > > +extern const struct attribute_group *peci_device_groups[]; > > > > int peci_device_create(struct peci_controller *controller, u8 addr); > > void peci_device_destroy(struct peci_device *device); > > > > extern struct bus_type peci_bus_type; > > +extern const struct attribute_group *peci_bus_groups[]; > > To me, sysfs.c is small enough to just fold into core.c, then no need > to declare public attribute arrays like this, but up to you if you > prefer the sysfs.c split. Left the sysfs split for now. > > > > > extern struct device_type peci_controller_type; > > > > +int peci_controller_scan_devices(struct peci_controller *controller); > > + > > #endif /* __PECI_INTERNAL_H */ > > diff --git a/drivers/peci/sysfs.c b/drivers/peci/sysfs.c > > new file mode 100644 > > index 000000000000..db9ef05776e3 > > --- /dev/null > > +++ b/drivers/peci/sysfs.c > > @@ -0,0 +1,82 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +// Copyright (c) 2021 Intel Corporation > > + > > +#include <linux/device.h> > > +#include <linux/kernel.h> > > +#include <linux/peci.h> > > + > > +#include "internal.h" > > + > > +static int rescan_controller(struct device *dev, void *data) > > +{ > > + if (dev->type != &peci_controller_type) > > + return 0; > > + > > + return peci_controller_scan_devices(to_peci_controller(dev)); > > +} > > + > > +static ssize_t rescan_store(struct bus_type *bus, const char *buf, size_t > > count) > > +{ > > + bool res; > > + int ret; > > + > > + ret = kstrtobool(buf, &res); > > + if (ret) > > + return ret; > > + > > + if (!res) > > + return count; > > + > > + ret = bus_for_each_dev(&peci_bus_type, NULL, NULL, > > rescan_controller); > > + if (ret) > > + return ret; > > + > > + return count; > > +} > > +static BUS_ATTR_WO(rescan); > > + > > +static struct attribute *peci_bus_attrs[] = { > > + &bus_attr_rescan.attr, > > + NULL > > +}; > > + > > +static const struct attribute_group peci_bus_group = { > > + .attrs = peci_bus_attrs, > > +}; > > + > > +const struct attribute_group *peci_bus_groups[] = { > > + &peci_bus_group, > > + NULL > > +}; > > + > > +static ssize_t remove_store(struct device *dev, struct device_attribute > > *attr, > > + const char *buf, size_t count) > > +{ > > + struct peci_device *device = to_peci_device(dev); > > + bool res; > > + int ret; > > + > > + ret = kstrtobool(buf, &res); > > + if (ret) > > + return ret; > > + > > + if (res && device_remove_file_self(dev, attr)) > > + peci_device_destroy(device); > > How do you solve races between sysfs device remove and controller > device remove? Looks like double-free at first glance. Have a look at > the kill_device() helper as one way to resolve this double-delete > race.. Done. Thanks -Iwona > > > + > > + return count; > > +} > > +static DEVICE_ATTR_IGNORE_LOCKDEP(remove, 0200, NULL, remove_store); > > + > > +static struct attribute *peci_device_attrs[] = { > > + &dev_attr_remove.attr, > > + NULL > > +}; > > + > > +static const struct attribute_group peci_device_group = { > > + .attrs = peci_device_attrs, > > +}; > > + > > +const struct attribute_group *peci_device_groups[] = { > > + &peci_device_group, > > + NULL > > +}; > > -- > > 2.31.1 > >
next prev parent reply other threads:[~2021-11-16 1:59 UTC|newest] Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-03 11:31 [PATCH v2 00/15] Introduce PECI subsystem Iwona Winiarska 2021-08-03 11:31 ` [PATCH v2 01/15] x86/cpu: Move intel-family to arch-independent headers Iwona Winiarska 2021-10-04 19:03 ` Borislav Petkov 2021-10-11 19:21 ` Winiarska, Iwona 2021-10-11 19:40 ` Dave Hansen 2021-10-11 20:53 ` Winiarska, Iwona 2021-10-11 23:12 ` Dave Hansen 2021-10-11 20:06 ` Borislav Petkov 2021-10-11 20:38 ` Winiarska, Iwona 2021-10-11 21:31 ` Borislav Petkov 2021-10-12 23:15 ` Winiarska, Iwona 2021-10-13 6:42 ` Borislav Petkov 2021-08-03 11:31 ` [PATCH v2 02/15] x86/cpu: Extract cpuid helpers to arch-independent Iwona Winiarska 2021-10-04 19:08 ` Borislav Petkov 2021-10-11 19:32 ` Winiarska, Iwona 2021-08-03 11:31 ` [PATCH v2 03/15] dt-bindings: Add generic bindings for PECI Iwona Winiarska 2021-08-11 18:11 ` Rob Herring 2021-08-03 11:31 ` [PATCH v2 04/15] dt-bindings: Add bindings for peci-aspeed Iwona Winiarska 2021-08-11 18:11 ` Rob Herring 2021-08-03 11:31 ` [PATCH v2 05/15] ARM: dts: aspeed: Add PECI controller nodes Iwona Winiarska 2021-08-03 11:31 ` [PATCH v2 06/15] peci: Add core infrastructure Iwona Winiarska 2021-08-25 22:58 ` Dan Williams 2021-08-26 22:40 ` Winiarska, Iwona 2021-08-03 11:31 ` [PATCH v2 07/15] peci: Add peci-aspeed controller driver Iwona Winiarska 2021-08-26 1:35 ` Dan Williams 2021-08-26 23:54 ` Winiarska, Iwona 2021-08-27 16:24 ` Dan Williams 2021-08-29 19:42 ` Winiarska, Iwona 2021-08-03 11:31 ` [PATCH v2 08/15] peci: Add device detection Iwona Winiarska 2021-08-27 19:01 ` Dan Williams 2021-11-15 22:18 ` Winiarska, Iwona 2021-08-03 11:31 ` [PATCH v2 09/15] peci: Add sysfs interface for PECI bus Iwona Winiarska 2021-08-27 19:11 ` Dan Williams 2021-11-15 22:19 ` Winiarska, Iwona [this message] 2021-08-03 11:31 ` [PATCH v2 10/15] peci: Add support for PECI device drivers Iwona Winiarska 2021-08-27 21:19 ` Dan Williams 2021-11-15 22:20 ` Winiarska, Iwona 2021-08-03 11:31 ` [PATCH v2 11/15] peci: Add peci-cpu driver Iwona Winiarska 2021-08-03 11:31 ` [PATCH v2 12/15] hwmon: peci: Add cputemp driver Iwona Winiarska 2021-08-03 15:24 ` Guenter Roeck 2021-08-04 10:43 ` Winiarska, Iwona 2021-08-03 11:31 ` [PATCH v2 13/15] hwmon: peci: Add dimmtemp driver Iwona Winiarska 2021-08-03 15:39 ` Guenter Roeck 2021-08-04 10:46 ` Winiarska, Iwona 2021-08-04 17:33 ` Guenter Roeck 2021-08-05 21:48 ` Winiarska, Iwona 2021-08-03 11:31 ` [PATCH v2 14/15] docs: hwmon: Document PECI drivers Iwona Winiarska 2021-08-03 11:31 ` [PATCH v2 15/15] docs: Add PECI documentation Iwona Winiarska 2021-08-05 12:17 ` [PATCH v2 00/15] Introduce PECI subsystem Greg Kroah-Hartman
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