| Message ID | 20230915172818.761-4-shiju.jose@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | ACPI:RASF: Add support for ACPI RASF, ACPI RAS2 and configure scrubbers | expand |
On 15.09.23 19:28, shiju.jose@huawei.com wrote: > From: Shiju Jose <shiju.jose@huawei.com> > > Add documentation for scrub driver, supports configure scrub parameters, > in Documentation/scrub-configure.rst > > Signed-off-by: Shiju Jose <shiju.jose@huawei.com> > --- > Documentation/scrub-configure.rst | 55 +++++++++++++++++++++++++++++++ > 1 file changed, 55 insertions(+) > create mode 100644 Documentation/scrub-configure.rst > > diff --git a/Documentation/scrub-configure.rst b/Documentation/scrub-configure.rst > new file mode 100644 > index 000000000000..9f8581b88788 > --- /dev/null > +++ b/Documentation/scrub-configure.rst > @@ -0,0 +1,55 @@ > +========================== > +Scrub subsystem driver > +========================== > + > +Copyright (c) 2023 HiSilicon Limited. > + > +:Author: Shiju Jose <shiju.jose@huawei.com> > +:License: The GNU Free Documentation License, Version 1.2 > + (dual licensed under the GPL v2) > +:Original Reviewers: > + > +- Written for: 6.7 > +- Updated for: > + > +Introduction > +------------ > +The scrub subsystem driver provides the interface for configure the "... interface for configuring memory scrubbers in the system." are we only configuring firmware/hw-based memory scrubbing? I assume so. > +parameters of memory scrubbers in the system. The scrub device drivers > +in the system register with the scrub configure subsystem. Maybe say a few words what memory scrubbing is, and what it is used for. > + > +The scrub configure driver exposes the scrub controls to the user > +via sysfs. > + > +The File System > +--------------- > + > +The configuration parameters of the registered scrubbers could be > +accessed via the /sys/class/scrub/scrubX/regionN/ > + > +sysfs > +----- > + > +Sysfs files are documented in > +`Documentation/ABI/testing/sysfs-class-scrub-configure`. > + > +Example > +------- > + > + The usage takes the form shown in this example:: > + > + # echo 0x300000 > /sys/class/scrub/scrub0/region0/addr_base > + # echo 0x100000 > /sys/class/scrub/scrub0/region0/addr_size > + # cat /sys/class/scrub/scrub0/region0/speed_available > + # 1-60 > + # echo 25 > /sys/class/scrub/scrub0/region0/speed > + # echo 1 > /sys/class/scrub/scrub0/region0/enable > + > + # cat /sys/class/scrub/scrub0/region0/speed > + # 0x19 Is it reasonable to return the speed as hex? You set it as dec. > + # cat /sys/class/scrub/scrub0/region0/addr_base > + # 0x100000 But didn't we set it to 0x300000 ... > + # cat /sys/class/scrub/scrub0/region0/addr_size > + # 0x200000 ... and didn't we set it to 0x100000 ? Or what's the magic happening here? > + > + # echo 0 > /sys/class/scrub/scrub0/region0/enable
On 18.09.23 12:25, Shiju Jose wrote: > Hi David, > > Thanks for looking into this. > >> -----Original Message----- >> From: David Hildenbrand <david@redhat.com> >> Sent: 18 September 2023 08:24 >> To: Shiju Jose <shiju.jose@huawei.com>; linux-acpi@vger.kernel.org; linux- >> mm@kvack.org; linux-kernel@vger.kernel.org >> Cc: rafael@kernel.org; lenb@kernel.org; naoya.horiguchi@nec.com; >> tony.luck@intel.com; james.morse@arm.com; dave.hansen@linux.intel.com; >> jiaqiyan@google.com; jthoughton@google.com; somasundaram.a@hpe.com; >> erdemaktas@google.com; pgonda@google.com; rientjes@google.com; >> duenwen@google.com; Vilas.Sridharan@amd.com; mike.malvestuto@intel.com; >> gthelen@google.com; Linuxarm <linuxarm@huawei.com>; Jonathan Cameron >> <jonathan.cameron@huawei.com>; tanxiaofei <tanxiaofei@huawei.com>; >> Zengtao (B) <prime.zeng@hisilicon.com> >> Subject: Re: [RFC PATCH 3/9] Documentation/scrub-configure.rst: Add >> documentation for scrub driver >> >> On 15.09.23 19:28, shiju.jose@huawei.com wrote: >>> From: Shiju Jose <shiju.jose@huawei.com> >>> >>> Add documentation for scrub driver, supports configure scrub >>> parameters, in Documentation/scrub-configure.rst >>> >>> Signed-off-by: Shiju Jose <shiju.jose@huawei.com> >>> --- >>> Documentation/scrub-configure.rst | 55 >> +++++++++++++++++++++++++++++++ >>> 1 file changed, 55 insertions(+) >>> create mode 100644 Documentation/scrub-configure.rst >>> >>> diff --git a/Documentation/scrub-configure.rst >>> b/Documentation/scrub-configure.rst >>> new file mode 100644 >>> index 000000000000..9f8581b88788 >>> --- /dev/null >>> +++ b/Documentation/scrub-configure.rst >>> @@ -0,0 +1,55 @@ >>> +========================== >>> +Scrub subsystem driver >>> +========================== >>> + >>> +Copyright (c) 2023 HiSilicon Limited. >>> + >>> +:Author: Shiju Jose <shiju.jose@huawei.com> >>> +:License: The GNU Free Documentation License, Version 1.2 >>> + (dual licensed under the GPL v2) :Original Reviewers: >>> + >>> +- Written for: 6.7 >>> +- Updated for: >>> + >>> +Introduction >>> +------------ >>> +The scrub subsystem driver provides the interface for configure the >> >> "... interface for configuring memory scrubbers in the system." >> >> are we only configuring firmware/hw-based memory scrubbing? I assume so. > The scrub control could be used for the SW based memory scrubbing too. Okay, looks like there is not too much hw/firmware specific in there (besides these weird range changes). [...] >>> +------- >>> + >>> + The usage takes the form shown in this example:: >>> + >>> + # echo 0x300000 > /sys/class/scrub/scrub0/region0/addr_base >>> + # echo 0x100000 > /sys/class/scrub/scrub0/region0/addr_size >>> + # cat /sys/class/scrub/scrub0/region0/speed_available >>> + # 1-60 >>> + # echo 25 > /sys/class/scrub/scrub0/region0/speed >>> + # echo 1 > /sys/class/scrub/scrub0/region0/enable >>> + >>> + # cat /sys/class/scrub/scrub0/region0/speed >>> + # 0x19 >> >> Is it reasonable to return the speed as hex? You set it as dec. > Presently return speed as hex to reduce the number of callback function needed > for reading the hex/dec data because the values for the address range > need to be in hex. If speed_available returns dec, speed better also return dec IMHO. > >> >>> + # cat /sys/class/scrub/scrub0/region0/addr_base >>> + # 0x100000 >> >> But didn't we set it to 0x300000 ... > This is an emulated example for testing the RASF/RAS2 definition. > According to the RASF & RAS2 definition, the actual address range in the > platform could vary from the requested address range for the patrol scrubbing. > "The platform calculates the nearest patrol scrub boundary address > from where it can start". The platform returns the actual address range > in response to GET_PATROL_PARAMETERS command to the firmware. > Please see section 5.2.21.2.1 Hardware-based Memory Scrubbing , > Table 5.87: Parameter Block Structure for PATROL_SCRUB in the > ACPI 6.5 specification. > So you configure [0x300000 - 0x400000] and you get [0x100000 - 0x300000] How does that make any sense? :) Shouldn't we rather return an error when setting a range that is impossible, instead of the hardware deciding to scrub something completely different (as can be seen in the example)?
On Mon, 18 Sep 2023 14:15:33 +0200 David Hildenbrand <david@redhat.com> wrote: > On 18.09.23 12:25, Shiju Jose wrote: > > Hi David, > > > > Thanks for looking into this. > > > >> -----Original Message----- > >> From: David Hildenbrand <david@redhat.com> > >> Sent: 18 September 2023 08:24 > >> To: Shiju Jose <shiju.jose@huawei.com>; linux-acpi@vger.kernel.org; linux- > >> mm@kvack.org; linux-kernel@vger.kernel.org > >> Cc: rafael@kernel.org; lenb@kernel.org; naoya.horiguchi@nec.com; > >> tony.luck@intel.com; james.morse@arm.com; dave.hansen@linux.intel.com; > >> jiaqiyan@google.com; jthoughton@google.com; somasundaram.a@hpe.com; > >> erdemaktas@google.com; pgonda@google.com; rientjes@google.com; > >> duenwen@google.com; Vilas.Sridharan@amd.com; mike.malvestuto@intel.com; > >> gthelen@google.com; Linuxarm <linuxarm@huawei.com>; Jonathan Cameron > >> <jonathan.cameron@huawei.com>; tanxiaofei <tanxiaofei@huawei.com>; > >> Zengtao (B) <prime.zeng@hisilicon.com> > >> Subject: Re: [RFC PATCH 3/9] Documentation/scrub-configure.rst: Add > >> documentation for scrub driver > >> > >> On 15.09.23 19:28, shiju.jose@huawei.com wrote: > >>> From: Shiju Jose <shiju.jose@huawei.com> > >>> > >>> Add documentation for scrub driver, supports configure scrub > >>> parameters, in Documentation/scrub-configure.rst > >>> > >>> Signed-off-by: Shiju Jose <shiju.jose@huawei.com> > >>> --- > >>> Documentation/scrub-configure.rst | 55 > >> +++++++++++++++++++++++++++++++ > >>> 1 file changed, 55 insertions(+) > >>> create mode 100644 Documentation/scrub-configure.rst > >>> > >>> diff --git a/Documentation/scrub-configure.rst > >>> b/Documentation/scrub-configure.rst > >>> new file mode 100644 > >>> index 000000000000..9f8581b88788 > >>> --- /dev/null > >>> +++ b/Documentation/scrub-configure.rst > >>> @@ -0,0 +1,55 @@ > >>> +========================== > >>> +Scrub subsystem driver > >>> +========================== > >>> + > >>> +Copyright (c) 2023 HiSilicon Limited. > >>> + > >>> +:Author: Shiju Jose <shiju.jose@huawei.com> > >>> +:License: The GNU Free Documentation License, Version 1.2 > >>> + (dual licensed under the GPL v2) :Original Reviewers: > >>> + > >>> +- Written for: 6.7 > >>> +- Updated for: > >>> + > >>> +Introduction > >>> +------------ > >>> +The scrub subsystem driver provides the interface for configure the > >> > >> "... interface for configuring memory scrubbers in the system." > >> > >> are we only configuring firmware/hw-based memory scrubbing? I assume so. > > The scrub control could be used for the SW based memory scrubbing too. > > Okay, looks like there is not too much hw/firmware specific in there > (besides these weird range changes). > [...] > > >>> +------- > >>> + > >>> + The usage takes the form shown in this example:: > >>> + > >>> + # echo 0x300000 > /sys/class/scrub/scrub0/region0/addr_base > >>> + # echo 0x100000 > /sys/class/scrub/scrub0/region0/addr_size > >>> + # cat /sys/class/scrub/scrub0/region0/speed_available > >>> + # 1-60 > >>> + # echo 25 > /sys/class/scrub/scrub0/region0/speed > >>> + # echo 1 > /sys/class/scrub/scrub0/region0/enable > >>> + > >>> + # cat /sys/class/scrub/scrub0/region0/speed > >>> + # 0x19 > >> > >> Is it reasonable to return the speed as hex? You set it as dec. > > Presently return speed as hex to reduce the number of callback function needed > > for reading the hex/dec data because the values for the address range > > need to be in hex. > > If speed_available returns dec, speed better also return dec IMHO. > > > > >> > >>> + # cat /sys/class/scrub/scrub0/region0/addr_base > >>> + # 0x100000 > >> > >> But didn't we set it to 0x300000 ... > > This is an emulated example for testing the RASF/RAS2 definition. > > According to the RASF & RAS2 definition, the actual address range in the > > platform could vary from the requested address range for the patrol scrubbing. > > "The platform calculates the nearest patrol scrub boundary address > > from where it can start". The platform returns the actual address range > > in response to GET_PATROL_PARAMETERS command to the firmware. > > Please see section 5.2.21.2.1 Hardware-based Memory Scrubbing , > > Table 5.87: Parameter Block Structure for PATROL_SCRUB in the > > ACPI 6.5 specification. > > > > So you configure [0x300000 - 0x400000] and you get [0x100000 - 0x300000] > > How does that make any sense? :) > > Shouldn't we rather return an error when setting a range that is > impossible, instead of the hardware deciding to scrub something > completely different (as can be seen in the example)? > A broader scrub is probably reasonable, but agreed that scrubbing narrower is 'interesting' as not scrubbing the memory requeseted. It's really annoying that neither ACPI table provides any proper discoverability. Whilst we can fix that long term, we are stuck with a clunky poke it and see interface in the meantime. Jonathan
On 18.09.23 14:28, Jonathan Cameron wrote: > On Mon, 18 Sep 2023 14:15:33 +0200 > David Hildenbrand <david@redhat.com> wrote: > >> On 18.09.23 12:25, Shiju Jose wrote: >>> Hi David, >>> >>> Thanks for looking into this. >>> >>>> -----Original Message----- >>>> From: David Hildenbrand <david@redhat.com> >>>> Sent: 18 September 2023 08:24 >>>> To: Shiju Jose <shiju.jose@huawei.com>; linux-acpi@vger.kernel.org; linux- >>>> mm@kvack.org; linux-kernel@vger.kernel.org >>>> Cc: rafael@kernel.org; lenb@kernel.org; naoya.horiguchi@nec.com; >>>> tony.luck@intel.com; james.morse@arm.com; dave.hansen@linux.intel.com; >>>> jiaqiyan@google.com; jthoughton@google.com; somasundaram.a@hpe.com; >>>> erdemaktas@google.com; pgonda@google.com; rientjes@google.com; >>>> duenwen@google.com; Vilas.Sridharan@amd.com; mike.malvestuto@intel.com; >>>> gthelen@google.com; Linuxarm <linuxarm@huawei.com>; Jonathan Cameron >>>> <jonathan.cameron@huawei.com>; tanxiaofei <tanxiaofei@huawei.com>; >>>> Zengtao (B) <prime.zeng@hisilicon.com> >>>> Subject: Re: [RFC PATCH 3/9] Documentation/scrub-configure.rst: Add >>>> documentation for scrub driver >>>> >>>> On 15.09.23 19:28, shiju.jose@huawei.com wrote: >>>>> From: Shiju Jose <shiju.jose@huawei.com> >>>>> >>>>> Add documentation for scrub driver, supports configure scrub >>>>> parameters, in Documentation/scrub-configure.rst >>>>> >>>>> Signed-off-by: Shiju Jose <shiju.jose@huawei.com> >>>>> --- >>>>> Documentation/scrub-configure.rst | 55 >>>> +++++++++++++++++++++++++++++++ >>>>> 1 file changed, 55 insertions(+) >>>>> create mode 100644 Documentation/scrub-configure.rst >>>>> >>>>> diff --git a/Documentation/scrub-configure.rst >>>>> b/Documentation/scrub-configure.rst >>>>> new file mode 100644 >>>>> index 000000000000..9f8581b88788 >>>>> --- /dev/null >>>>> +++ b/Documentation/scrub-configure.rst >>>>> @@ -0,0 +1,55 @@ >>>>> +========================== >>>>> +Scrub subsystem driver >>>>> +========================== >>>>> + >>>>> +Copyright (c) 2023 HiSilicon Limited. >>>>> + >>>>> +:Author: Shiju Jose <shiju.jose@huawei.com> >>>>> +:License: The GNU Free Documentation License, Version 1.2 >>>>> + (dual licensed under the GPL v2) :Original Reviewers: >>>>> + >>>>> +- Written for: 6.7 >>>>> +- Updated for: >>>>> + >>>>> +Introduction >>>>> +------------ >>>>> +The scrub subsystem driver provides the interface for configure the >>>> >>>> "... interface for configuring memory scrubbers in the system." >>>> >>>> are we only configuring firmware/hw-based memory scrubbing? I assume so. >>> The scrub control could be used for the SW based memory scrubbing too. >> >> Okay, looks like there is not too much hw/firmware specific in there >> (besides these weird range changes). >> [...] >> >>>>> +------- >>>>> + >>>>> + The usage takes the form shown in this example:: >>>>> + >>>>> + # echo 0x300000 > /sys/class/scrub/scrub0/region0/addr_base >>>>> + # echo 0x100000 > /sys/class/scrub/scrub0/region0/addr_size >>>>> + # cat /sys/class/scrub/scrub0/region0/speed_available >>>>> + # 1-60 >>>>> + # echo 25 > /sys/class/scrub/scrub0/region0/speed >>>>> + # echo 1 > /sys/class/scrub/scrub0/region0/enable >>>>> + >>>>> + # cat /sys/class/scrub/scrub0/region0/speed >>>>> + # 0x19 >>>> >>>> Is it reasonable to return the speed as hex? You set it as dec. >>> Presently return speed as hex to reduce the number of callback function needed >>> for reading the hex/dec data because the values for the address range >>> need to be in hex. >> >> If speed_available returns dec, speed better also return dec IMHO. >> >>> >>>> >>>>> + # cat /sys/class/scrub/scrub0/region0/addr_base >>>>> + # 0x100000 >>>> >>>> But didn't we set it to 0x300000 ... >>> This is an emulated example for testing the RASF/RAS2 definition. >>> According to the RASF & RAS2 definition, the actual address range in the >>> platform could vary from the requested address range for the patrol scrubbing. >>> "The platform calculates the nearest patrol scrub boundary address >>> from where it can start". The platform returns the actual address range >>> in response to GET_PATROL_PARAMETERS command to the firmware. >>> Please see section 5.2.21.2.1 Hardware-based Memory Scrubbing , >>> Table 5.87: Parameter Block Structure for PATROL_SCRUB in the >>> ACPI 6.5 specification. >>> >> >> So you configure [0x300000 - 0x400000] and you get [0x100000 - 0x300000] >> >> How does that make any sense? :) >> >> Shouldn't we rather return an error when setting a range that is >> impossible, instead of the hardware deciding to scrub something >> completely different (as can be seen in the example)? >> > > A broader scrub is probably reasonable, but agreed that scrubbing narrower > is 'interesting' as not scrubbing the memory requeseted. It's not even narrower. Both ranges don't even intersect! (sorry to say, but this configuration interface doesn't make any sense if hardware just does *something* else). If you can't configure it properly, fail with an error. > It's really annoying that neither ACPI table provides any proper > discoverability. Whilst we can fix that long term, we are stuck with > a clunky poke it and see interface in the meantime. Can't you set it, briefly enable it, and read the values back? Then, you can complain to the user that the configured range is impossible.
>-----Original Message----- >From: David Hildenbrand <david@redhat.com> >Sent: 18 September 2023 13:35 >To: Jonathan Cameron <jonathan.cameron@huawei.com>; Linuxarm ><linuxarm@huawei.com> >Cc: Shiju Jose <shiju.jose@huawei.com>; linux-acpi@vger.kernel.org; linux- >mm@kvack.org; linux-kernel@vger.kernel.org; rafael@kernel.org; >lenb@kernel.org; naoya.horiguchi@nec.com; tony.luck@intel.com; >james.morse@arm.com; dave.hansen@linux.intel.com; jiaqiyan@google.com; >jthoughton@google.com; somasundaram.a@hpe.com; >erdemaktas@google.com; pgonda@google.com; rientjes@google.com; >duenwen@google.com; Vilas.Sridharan@amd.com; mike.malvestuto@intel.com; >gthelen@google.com; tanxiaofei <tanxiaofei@huawei.com>; Zengtao (B) ><prime.zeng@hisilicon.com> >Subject: Re: [RFC PATCH 3/9] Documentation/scrub-configure.rst: Add >documentation for scrub driver > >On 18.09.23 14:28, Jonathan Cameron wrote: >> On Mon, 18 Sep 2023 14:15:33 +0200 >> David Hildenbrand <david@redhat.com> wrote: >> >>> On 18.09.23 12:25, Shiju Jose wrote: >>>> Hi David, >>>> >>>> Thanks for looking into this. >>>> >>>>> -----Original Message----- >>>>> From: David Hildenbrand <david@redhat.com> >>>>> Sent: 18 September 2023 08:24 >>>>> To: Shiju Jose <shiju.jose@huawei.com>; linux-acpi@vger.kernel.org; >>>>> linux- mm@kvack.org; linux-kernel@vger.kernel.org >>>>> Cc: rafael@kernel.org; lenb@kernel.org; naoya.horiguchi@nec.com; >>>>> tony.luck@intel.com; james.morse@arm.com; >>>>> dave.hansen@linux.intel.com; jiaqiyan@google.com; >>>>> jthoughton@google.com; somasundaram.a@hpe.com; >>>>> erdemaktas@google.com; pgonda@google.com; rientjes@google.com; >>>>> duenwen@google.com; Vilas.Sridharan@amd.com; >>>>> mike.malvestuto@intel.com; gthelen@google.com; Linuxarm >>>>> <linuxarm@huawei.com>; Jonathan Cameron >>>>> <jonathan.cameron@huawei.com>; tanxiaofei <tanxiaofei@huawei.com>; >>>>> Zengtao (B) <prime.zeng@hisilicon.com> >>>>> Subject: Re: [RFC PATCH 3/9] Documentation/scrub-configure.rst: Add >>>>> documentation for scrub driver >>>>> >>>>> On 15.09.23 19:28, shiju.jose@huawei.com wrote: >>>>>> From: Shiju Jose <shiju.jose@huawei.com> >>>>>> >>>>>> Add documentation for scrub driver, supports configure scrub >>>>>> parameters, in Documentation/scrub-configure.rst >>>>>> >>>>>> Signed-off-by: Shiju Jose <shiju.jose@huawei.com> >>>>>> --- >>>>>> Documentation/scrub-configure.rst | 55 >>>>> +++++++++++++++++++++++++++++++ >>>>>> 1 file changed, 55 insertions(+) >>>>>> create mode 100644 Documentation/scrub-configure.rst >>>>>> >>>>>> diff --git a/Documentation/scrub-configure.rst >>>>>> b/Documentation/scrub-configure.rst >>>>>> new file mode 100644 >>>>>> index 000000000000..9f8581b88788 >>>>>> --- /dev/null >>>>>> +++ b/Documentation/scrub-configure.rst >>>>>> @@ -0,0 +1,55 @@ >>>>>> +========================== >>>>>> +Scrub subsystem driver >>>>>> +========================== >>>>>> + >>>>>> +Copyright (c) 2023 HiSilicon Limited. >>>>>> + >>>>>> +:Author: Shiju Jose <shiju.jose@huawei.com> >>>>>> +:License: The GNU Free Documentation License, Version 1.2 >>>>>> + (dual licensed under the GPL v2) :Original Reviewers: >>>>>> + >>>>>> +- Written for: 6.7 >>>>>> +- Updated for: >>>>>> + >>>>>> +Introduction >>>>>> +------------ >>>>>> +The scrub subsystem driver provides the interface for configure >>>>>> +the >>>>> >>>>> "... interface for configuring memory scrubbers in the system." >>>>> >>>>> are we only configuring firmware/hw-based memory scrubbing? I assume >so. >>>> The scrub control could be used for the SW based memory scrubbing too. >>> >>> Okay, looks like there is not too much hw/firmware specific in there >>> (besides these weird range changes). >>> [...] >>> >>>>>> +------- >>>>>> + >>>>>> + The usage takes the form shown in this example:: >>>>>> + >>>>>> + # echo 0x300000 > /sys/class/scrub/scrub0/region0/addr_base >>>>>> + # echo 0x100000 > /sys/class/scrub/scrub0/region0/addr_size >>>>>> + # cat /sys/class/scrub/scrub0/region0/speed_available >>>>>> + # 1-60 >>>>>> + # echo 25 > /sys/class/scrub/scrub0/region0/speed >>>>>> + # echo 1 > /sys/class/scrub/scrub0/region0/enable >>>>>> + >>>>>> + # cat /sys/class/scrub/scrub0/region0/speed >>>>>> + # 0x19 >>>>> >>>>> Is it reasonable to return the speed as hex? You set it as dec. >>>> Presently return speed as hex to reduce the number of callback >>>> function needed for reading the hex/dec data because the values for >>>> the address range need to be in hex. >>> >>> If speed_available returns dec, speed better also return dec IMHO. >>> >>>> >>>>> >>>>>> + # cat /sys/class/scrub/scrub0/region0/addr_base >>>>>> + # 0x100000 >>>>> >>>>> But didn't we set it to 0x300000 ... >>>> This is an emulated example for testing the RASF/RAS2 definition. >>>> According to the RASF & RAS2 definition, the actual address range in >>>> the platform could vary from the requested address range for the patrol >scrubbing. >>>> "The platform calculates the nearest patrol scrub boundary address >>>> from where it can start". The platform returns the actual address >>>> range in response to GET_PATROL_PARAMETERS command to the >firmware. >>>> Please see section 5.2.21.2.1 Hardware-based Memory Scrubbing , >>>> Table 5.87: Parameter Block Structure for PATROL_SCRUB in the ACPI >>>> 6.5 specification. >>>> >>> >>> So you configure [0x300000 - 0x400000] and you get [0x100000 - >>> 0x300000] >>> >>> How does that make any sense? :) >>> >>> Shouldn't we rather return an error when setting a range that is >>> impossible, instead of the hardware deciding to scrub something >>> completely different (as can be seen in the example)? >>> >> >> A broader scrub is probably reasonable, but agreed that scrubbing >> narrower is 'interesting' as not scrubbing the memory requeseted. > >It's not even narrower. Both ranges don't even intersect! (sorry to say, but this >configuration interface doesn't make any sense if hardware just does >*something* else). > >If you can't configure it properly, fail with an error. > >> It's really annoying that neither ACPI table provides any proper >> discoverability. Whilst we can fix that long term, we are stuck with >> a clunky poke it and see interface in the meantime. > >Can't you set it, briefly enable it, and read the values back? Then, you can >complain to the user that the configured range is impossible. Will try to add report to the user that the configured address range is not possible. > >-- >Cheers, > >David / dhildenb Thanks, Shiju
diff --git a/Documentation/scrub-configure.rst b/Documentation/scrub-configure.rst new file mode 100644 index 000000000000..9f8581b88788 --- /dev/null +++ b/Documentation/scrub-configure.rst @@ -0,0 +1,55 @@ +========================== +Scrub subsystem driver +========================== + +Copyright (c) 2023 HiSilicon Limited. + +:Author: Shiju Jose <shiju.jose@huawei.com> +:License: The GNU Free Documentation License, Version 1.2 + (dual licensed under the GPL v2) +:Original Reviewers: + +- Written for: 6.7 +- Updated for: + +Introduction +------------ +The scrub subsystem driver provides the interface for configure the +parameters of memory scrubbers in the system. The scrub device drivers +in the system register with the scrub configure subsystem. + +The scrub configure driver exposes the scrub controls to the user +via sysfs. + +The File System +--------------- + +The configuration parameters of the registered scrubbers could be +accessed via the /sys/class/scrub/scrubX/regionN/ + +sysfs +----- + +Sysfs files are documented in +`Documentation/ABI/testing/sysfs-class-scrub-configure`. + +Example +------- + + The usage takes the form shown in this example:: + + # echo 0x300000 > /sys/class/scrub/scrub0/region0/addr_base + # echo 0x100000 > /sys/class/scrub/scrub0/region0/addr_size + # cat /sys/class/scrub/scrub0/region0/speed_available + # 1-60 + # echo 25 > /sys/class/scrub/scrub0/region0/speed + # echo 1 > /sys/class/scrub/scrub0/region0/enable + + # cat /sys/class/scrub/scrub0/region0/speed + # 0x19 + # cat /sys/class/scrub/scrub0/region0/addr_base + # 0x100000 + # cat /sys/class/scrub/scrub0/region0/addr_size + # 0x200000 + + # echo 0 > /sys/class/scrub/scrub0/region0/enable