+boot-architecture list
On Tue, Feb 19, 2019 at 07:52:47PM +0800, liaoweixiong wrote:
Create DT binding document for blkoops.
Signed-off-by: liaoweixiong liaoweixiong@allwinnertech.com
.../devicetree/bindings/pstore/blkoops.txt | 53 ++++++++++++++++++++++ MAINTAINERS | 1 + 2 files changed, 54 insertions(+) create mode 100644 Documentation/devicetree/bindings/pstore/blkoops.txt
diff --git a/Documentation/devicetree/bindings/pstore/blkoops.txt b/Documentation/devicetree/bindings/pstore/blkoops.txt new file mode 100644 index 0000000..5462915 --- /dev/null +++ b/Documentation/devicetree/bindings/pstore/blkoops.txt @@ -0,0 +1,53 @@ +Blkoops oops logger +===================
+Blkoops provides a block partition for oops, excluding panics now, so they can +be recovered after a reboot.
+Any space of block device will be used for a circular buffer of oops records. +These records have a configurable size, with a size of 0 indicating that they +should be disabled.
+At least one of "block-device" and "total_size" must be set.
+At least one of "dmesg-size" or "pmsg-size" must be set non-zero.
+Required properties:
+- compatible: must be "blkoops".
+Optional properties:
+- block-device: The block device to use. Most of the time, it is a partition of
device. If block-device is NULL, no block device is effectiveand the data will be lost after rebooting.It accept the following variants:1) <hex_major><hex_minor> device number in hexadecimalrepresents itself no leading 0x, for example b302.2) /dev/<disk_name> represents the device number of disk3) /dev/<disk_name><decimal> represents the device number ofpartition - device number of disk plus the partition number4) /dev/<disk_name>p<decimal> - same as the above, that form isused when disk name of partitioned disk ends on a digit.5) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representingthe unique id of a partition if the partition table providesit. The UUID may be either an EFI/GPT UUID, or refer to anMSDOS partition using the format SSSSSSSS-PP, where SSSSSSSSis a zero-filled hex representation of the 32-bit"NT disk signature", and PP is a zero-filled hexrepresentation of the 1-based partition number.6) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition inrelation to a partition with a known unique id.7) <major>:<minor> major and minor number of the deviceseparated by a colon.
No.
I didn't suggest to go look at PARTUUID to copy it into the binding, but rather to point out that the kernel can already mount by UUID. Specifying the UUID in DT is also not what I suggested. My suggestion is to define a known UUID so that the kernel (and bootloaders, userspace, the world) can just know the UUID. Just like the EFI system partition. Now this means you have to get it defined in the UEFI specification (or maybe EBBR[1]). If you want help with how to do that, the boot-architecture list is a good place to start.
major/minor numbers are a Linux thing, so they don't go in DT. /dev/* is Linux thing, so it doesn't go in DT.
You can always define all these parameters as kernel command line options and avoid DT. That would also make this work on *all* systems, not just DT based systems. (Though I still believe that the partition should be discoverable.)
Rob
On 2019-02-22 23:36, Rob Herring wrote:
+boot-architecture list
On Tue, Feb 19, 2019 at 07:52:47PM +0800, liaoweixiong wrote:
Create DT binding document for blkoops.
Signed-off-by: liaoweixiong liaoweixiong@allwinnertech.com
.../devicetree/bindings/pstore/blkoops.txt | 53 ++++++++++++++++++++++ MAINTAINERS | 1 + 2 files changed, 54 insertions(+) create mode 100644 Documentation/devicetree/bindings/pstore/blkoops.txt
diff --git a/Documentation/devicetree/bindings/pstore/blkoops.txt b/Documentation/devicetree/bindings/pstore/blkoops.txt new file mode 100644 index 0000000..5462915 --- /dev/null +++ b/Documentation/devicetree/bindings/pstore/blkoops.txt @@ -0,0 +1,53 @@ +Blkoops oops logger +===================
+Blkoops provides a block partition for oops, excluding panics now, so they can +be recovered after a reboot.
+Any space of block device will be used for a circular buffer of oops records. +These records have a configurable size, with a size of 0 indicating that they +should be disabled.
+At least one of "block-device" and "total_size" must be set.
+At least one of "dmesg-size" or "pmsg-size" must be set non-zero.
+Required properties:
+- compatible: must be "blkoops".
+Optional properties:
+- block-device: The block device to use. Most of the time, it is a partition of
device. If block-device is NULL, no block device is effectiveand the data will be lost after rebooting.It accept the following variants:1) <hex_major><hex_minor> device number in hexadecimalrepresents itself no leading 0x, for example b302.2) /dev/<disk_name> represents the device number of disk3) /dev/<disk_name><decimal> represents the device number ofpartition - device number of disk plus the partition number4) /dev/<disk_name>p<decimal> - same as the above, that form isused when disk name of partitioned disk ends on a digit.5) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representingthe unique id of a partition if the partition table providesit. The UUID may be either an EFI/GPT UUID, or refer to anMSDOS partition using the format SSSSSSSS-PP, where SSSSSSSSis a zero-filled hex representation of the 32-bit"NT disk signature", and PP is a zero-filled hexrepresentation of the 1-based partition number.6) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition inrelation to a partition with a known unique id.7) <major>:<minor> major and minor number of the deviceseparated by a colon.No.
I didn't suggest to go look at PARTUUID to copy it into the binding, but rather to point out that the kernel can already mount by UUID. Specifying the UUID in DT is also not what I suggested. My suggestion is to define a known UUID so that the kernel (and bootloaders, userspace, the world) can just know the UUID. Just like the EFI system partition. Now this means you have to get it defined in the UEFI specification (or maybe EBBR[1]). If you want help with how to do that, the boot-architecture list is a good place to start.
Thanks for your suggestion. I don't know whether it is a good idea to define a known UUID for pstore/blk in the UEFI specification. This property is only used for pstore/blk to know which block device it can use. It only works on linux. I think more thorough and rigorous consideration is needed. Besides that, mbr partition table has no partition UUID, how can it to be compatible with mbr?
major/minor numbers are a Linux thing, so they don't go in DT. /dev/* is Linux thing, so it doesn't go in DT.
You can always define all these parameters as kernel command line options and avoid DT. That would also make this work on *all* systems, not just DT based systems. (Though I still believe that the partition should be discoverable.)
The pstore/blk has already support command line. It now has 3 configuration methods, they are kconfig, DT and module parameters. I will cancel DT support on next version until we discuss a viable approach by this mail and than i will submit other patches to implement DT. Is this ok?
Rob
boot-architecture@lists.linaro.org
-
liaoweixiong -
Rob Herring