On Fri, 26 Apr 2024 20:34:00 -0700 Ira Weiny <ira.weiny@xxxxxxxxx> wrote: > BIOS can configure memory devices as firmware first. This will send CXL > events to the firmware instead of the OS. The firmware can then inform > the OS of these events via UEFI. > > UEFI v2.10 section N.2.14 defines a Common Platform Error Record (CPER) > format for CXL Component Events. The format is mostly the same as the > CXL Common Event Record Format. The difference lies in the use of a > GUID as the CPER Section Type which matches the UUID defined in CXL 3.1 > Table 8-43. > > Currently a configuration such as this will trace a non standard event > in the log omitting useful details of the event. In addition the CXL > sub-system contains additional region and HPA information useful to the > user.[0] > > The CXL code is required to be called from process context as it needs > to take a device lock. The GHES code may be in interrupt context. This > complicated the use of a callback. Dan Williams suggested the use of > work items as an atomic way of switching between the callback execution > and a default handler.[1] > > The use of a kfifo simplifies queue processing by providing lock free > fifo operations. cxl_cper_kfifo_get() allows easier management of the > kfifo between the ghes and cxl modules. > > CXL 3.1 Table 8-127 requires a device to have a queue depth of 1 for > each of the four event logs. A combined queue depth of 32 is chosen to > provide room for 8 entries of each log type. > > Add GHES support to detect CXL CPER records. Add the ability for the > CXL sub-system to register a work queue to process the events. > > This patch adds back the functionality which was removed to fix the > report by Dan Carpenter[2]. > > Cc: Ard Biesheuvel <ardb@xxxxxxxxxx> > Cc: Rafael J. Wysocki <rafael@xxxxxxxxxx> > Cc: Tony Luck <tony.luck@xxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxxxx> > Suggested-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx> > Link: http://lore.kernel.org/r/cover.1711598777.git.alison.schofield@xxxxxxxxx [0] > Link: http://lore.kernel.org/r/65d111eb87115_6c745294ac@xxxxxxxxxxxxxxxxxxxxxxxxx.notmuch [1] > Link: http://lore.kernel.org/r/b963c490-2c13-4b79-bbe7-34c6568423c7@moroto.mountain [2] > Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx> > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> Totally trivial comment inline. Maybe Dave can tweak whilst applying... Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > diff --git a/include/linux/cxl-event.h b/include/linux/cxl-event.h > index 03fa6d50d46f..a0067c49e2ca 100644 > --- a/include/linux/cxl-event.h > +++ b/include/linux/cxl-event.h > @@ -3,6 +3,8 @@ > #ifndef _LINUX_CXL_EVENT_H > #define _LINUX_CXL_EVENT_H > > +#include <linux/workqueue_types.h> > + > /* > * Common Event Record Format > * CXL rev 3.0 section 8.2.9.2.1; Table 8-42 > @@ -140,4 +142,29 @@ struct cxl_cper_event_rec { > union cxl_event event; > } __packed; > > +struct cxl_cper_work_data { > + enum cxl_event_type event_type; > + struct cxl_cper_event_rec rec; > +}; > + > +#ifdef CONFIG_ACPI_APEI_GHES > +int cxl_cper_register_work(struct work_struct *work); > +int cxl_cper_unregister_work(struct work_struct *work); > +int cxl_cper_kfifo_get(struct cxl_cper_work_data *wd); > +#else > +static inline int cxl_cper_register_work(struct work_struct *work); > +{ > + return 0; > +} > + > +static inline int cxl_cper_unregister_work(struct work_struct *work); > +{ > + return 0; > +} Trivial note of the day: Inconsistent spacing - add a blank line here. > +static inline int cxl_cper_kfifo_get(struct cxl_cper_work_data *wd) > +{ > + return 0; > +} > +#endif > + > #endif /* _LINUX_CXL_EVENT_H */ >
