boot-architecture

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651 discussions

Question: how to identify vendor firmware setups conflicting with disk partitions?

by Steve McIntyre

Hi folks, I've just been having a discussion with folks about installing Debian on an arm64 device. Another developer is booting via U-Boot with UEFI and things are working OK, except... The intructions for their board [0] include writing things raw to both sector 0 and sector 1 of an SD card, meaning that both MBR and GPT partitioning schemes are likely to break. Ugh. :-/ So, I have two (related) worries: 1. At the moment in Debian, our installer will default to using GPT for arm64 machines (where disks are not already formatted). That was fine when we were expecting server systems booting using edk2, but it looks like that's now a dangerous assumption, as more and more U-Boot devices are out there which will be wanting to load firmware from low-numbered LBAs. 2. I'm just in the middle of adding EFI armhf installer support, and that is also (currently) defaulting to GPT if you've booted via EFI. This is fine for VMs booted using a 32-bit Arm build of edk2, but also it's starting to look like a bad option for real boards booting using U-Boot's EFI support (for similar reasons). The "Firmware Storage" section of EBBR v0.6 touches on this and describes how to store firmware in a safer manner, but obviously (some/many) vendors are not following the spec thus far. What are other folks doing in this area? How do you recognise which devices it's safe to use GPT on, for example? I'm now looking at updating our logic on armhf/arm64 to do something like: if (booted via UEFI); then if (booted using U-Boot); then echo MBR else echo GPT fi else echo MBR fi but I'll need to find a sane way to detect U-Boot->UEFI boot. For now I'm looking at parsing dmesg output to look for something like [ 0.000000] efi: EFI v2.70 by Das U-Boot but I'm hoping for a better solution. This is also somewhat assuming that detecting U-Boot in the boot chain is a valid indicator for "unsafe location for firmware", but I'm not sure of a better way! [0] http://share.loverpi.com/board/libre-computer-project/libre-computer-board-… Cheers, -- Steve McIntyre steve.mcintyre(a)linaro.org <http://www.linaro.org/> Linaro.org | Open source software for ARM SoCs

6 years, 6 months

Re: [RFC v9 2/5] dt-bindings: pstore-block: new support for blkoops

by Rob Herring

+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(a)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 effective > + and the data will be lost after rebooting. > + It accept the following variants: > + 1) <hex_major><hex_minor> device number in hexadecimal > + represents itself no leading 0x, for example b302. > + 2) /dev/<disk_name> represents the device number of disk > + 3) /dev/<disk_name><decimal> represents the device number of > + partition - device number of disk plus the partition number > + 4) /dev/<disk_name>p<decimal> - same as the above, that form is > + used when disk name of partitioned disk ends on a digit. > + 5) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing > + the unique id of a partition if the partition table provides > + it. The UUID may be either an EFI/GPT UUID, or refer to an > + MSDOS partition using the format SSSSSSSS-PP, where SSSSSSSS > + is a zero-filled hex representation of the 32-bit > + "NT disk signature", and PP is a zero-filled hex > + representation of the 1-based partition number. > + 6) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in > + relation to a partition with a known unique id. > + 7) <major>:<minor> major and minor number of the device > + separated 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 [1] https://github.com/ARM-software/ebbr

6 years, 6 months

[PATCH] Simplify SetVariable() language

by Grant Likely

Instead of masking out GetVariable() when SetVariable() isn't available during runtime services, simplify the requirements without losing the ability to read variables by using the RuntimeServicesSupported variable from UEFI v2.8.1 (unreleased); Mantis issue 1961. Peter Jones's earlier patch also specified a Capsule-on-Disk format for updating variables that the OS could store in the ESP. I've not included that specification in this patch as it is logically a separate feature. It may reappear in a separate patch at a later date, or it may get proposed for inclusion in the UEFI spec proper. Signed-off-by: Grant Likely <grant.likely(a)arm.com> Cc: Peter Jones <pjones(a)redhat.com> --- source/chapter2-uefi.rst | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst index 379f0ca..4f74d43 100644 --- a/source/chapter2-uefi.rst +++ b/source/chapter2-uefi.rst @@ -201,14 +201,15 @@ variables stored on shared media. [#OPTEESupplicant]_ If a platform does not implement modifying non-volatile variables with SetVariable() after ExitBootServices(), -then it must not provide any variable operations after ExitBootServices(). -Firmware shall return EFI_UNSUPPORTED for any call to GetVariable(), -GetNextVariableName() and SetVariable(). -Firmware shall not emulated non-volatile variables using volatile RAM cache. +then firmware shall return EFI_UNSUPPORTED for any call to SetVariable(), +and must advertise that SetVariable() isn't available during runtime services +via the "RuntimeServicesSupported" variable as defined in UEFI version 2.8.1. +EFI applications can read RuntimeServicesSupported to determine if calls +to SetVariable() need to be performed before calling ExitBootServices(). -.. note:: The behaviour when SetVariable() is not supported during runtime - services is still under discussion and subject to change. - Do not make any firmware implementation decisions based on this text yet. +Even when SetVariable() is not supported during runtime services, firmware +should cache variable names and values in EfiRuntimeServicesData memory so +that GetVariable() and GetNextVeriableName() can behave as specified. .. [#OPTEESupplicant] It is worth noting that OP-TEE has a similar problem regarding secure storage. @@ -216,5 +217,7 @@ Firmware shall not emulated non-volatile variables using volatile RAM cache. storage operations on behalf of OP-TEE. The same solution may be applicable to solving the UEFI non-volatile variable problem, but it requires additional OS support to work. + Regardless, EBBR compliance does not require SetVariable() support + during runtime services. https://github.com/OP-TEE/optee_os/blob/master/documentation/secure_storage… -- 2.13.0

6 years, 8 months

EBBR Meeting Cancelled - 13 Dec 2018

by Grant Likely

Sorry, but I have to cancel today's meeting due to high priority interrupt. We will meet next week (20th Dec), and then break until next year. g.

6 years, 9 months

Re: Moving ARM dts files

by Rob Herring

On Fri, Dec 7, 2018 at 9:16 AM Mark Brown <broonie(a)kernel.org> wrote: > > On Fri, Dec 07, 2018 at 08:57:06AM -0600, Rob Herring wrote: > > On Thu, Dec 6, 2018 at 2:07 PM Mark Brown <broonie(a)kernel.org> wrote: > > > > The issues with the existing install_dtbs sounded unrelated to this. > > > Maybe, what are the issues? We can't change the source layout > > transparently if dtbs_install is not being used. > > I thought that was the thing with adding -@ so overlays could be used? I don't think so as that is during building, not install. Any user can set '-@' with 'make DTC_FLAGS="-@" ...' already. The issue with that was changing the default globally and no way to set per platform. Now that I think about, moving the sources to subdirs may allow setting DTC_FLAGS per subdir which may be good enough. Rob

6 years, 9 months

Re: Moving ARM dts files

by Rob Herring

On Thu, Dec 6, 2018 at 2:07 PM Mark Brown <broonie(a)kernel.org> wrote: > > On Thu, Dec 06, 2018 at 01:06:43PM -0600, Rob Herring wrote: > > On Thu, Dec 6, 2018 at 7:32 AM Andreas Färber <afaerber(a)suse.de> wrote: > > > > I'd be okay with distinguishing source vs. install location. Due to the > > > issue I mention below (and more) we can't use install_dtbs for openSUSE > > > and had to reimplement it, which we'd need to (and can) adjust. > > > What would be needed for dtbs_install to work? arm64 needs to support > > a flat install? If it doesn't work for Debian or openSUSE, I'm not > > sure why we have it. So I'd like to make it work. > > Correct me if I'm wrong but as far as the flat vs directory thing goes > isn't the issue that this winds up being a rename for an existing 32 bit > system? If you just install the dtbs in the default location then a > bootloader or whatever that is hard coded to look for foo-bar.dtb won't > see the new foo/foo-bar.dtb (or whatever) and will continue to use the > old binary. It's not the fact that that it's in a directory, it's the > fact that the bootloader sees the name it needs to look for change (if > it's looking on a filesystem at all). Correct. > This isn't a problem for arm64 as > the location isn't changing, it's used directories from day one. The kernel may have used directories, but that's not what the distros did according to Andreas: > We already had that discussion for arm64 because Debian chose to ignore > the kernel-installed subdirectories and installed .dtb files into a flat > directory, which collided with openSUSE sticking to the kernel choice. So are the distros different or who changed to align? That's not clear from this thread. > The issues with the existing install_dtbs sounded unrelated to this. Maybe, what are the issues? We can't change the source layout transparently if dtbs_install is not being used. My question here is whether a flat install is useful on arm64. We can either have a kconfig variable that arm32 sets to do flat installs or it could be some command line make variable and then any user can pick what they want for any arch. Rob

6 years, 9 months

Re: Moving ARM dts files

by Olof Johansson

On Thu, Dec 6, 2018 at 12:07 PM Mark Brown <broonie(a)kernel.org> wrote: > > On Thu, Dec 06, 2018 at 01:06:43PM -0600, Rob Herring wrote: > > On Thu, Dec 6, 2018 at 7:32 AM Andreas Färber <afaerber(a)suse.de> wrote: > > > > I'd be okay with distinguishing source vs. install location. Due to the > > > issue I mention below (and more) we can't use install_dtbs for openSUSE > > > and had to reimplement it, which we'd need to (and can) adjust. > > > What would be needed for dtbs_install to work? arm64 needs to support > > a flat install? If it doesn't work for Debian or openSUSE, I'm not > > sure why we have it. So I'd like to make it work. > > Correct me if I'm wrong but as far as the flat vs directory thing goes > isn't the issue that this winds up being a rename for an existing 32 bit > system? If you just install the dtbs in the default location then a > bootloader or whatever that is hard coded to look for foo-bar.dtb won't > see the new foo/foo-bar.dtb (or whatever) and will continue to use the > old binary. It's not the fact that that it's in a directory, it's the > fact that the bootloader sees the name it needs to look for change (if > it's looking on a filesystem at all). This isn't a problem for arm64 as > the location isn't changing, it's used directories from day one. Yeah, install needs to remain flat even if the dts files move into subdirectories. It will be painful for everybody if the install location moves. > The issues with the existing install_dtbs sounded unrelated to this. Agreed. -Olof

6 years, 9 months

Re: Moving ARM dts files

by Andreas Färber

Rob, Am 04.12.18 um 19:36 schrieb Rob Herring: > I've put together a script to move the dts files and update the > makefiles. It doesn't handle files not following a common prefix which > isn't many and some includes within the dts files will need some fixups > by hand. > > MAINTAINERS will also need updating. > > A few questions: > > Do we want to move absolutely everything to subdirs? This refactoring is a terrible idea! While it would've been nice to have more structure from the start, bootloaders like U-Boot expect a flat structure for arm .dtb files now. If you start installing them into subdirs instead, they won't find the files anymore under the hardcoded name. Doing this only for new platforms would be much less invasive and allow to prepare bootloaders accordingly. Alternatively, white-list which ones are safe to move around. But don't just script a refactoring because it looks nicer in the source tree, without testing what side effects this can have for board/distro users of the compiled files in practice. We already had that discussion for arm64 because Debian chose to ignore the kernel-installed subdirectories and installed .dtb files into a flat directory, which collided with openSUSE sticking to the kernel choice. This topic becomes even more important with EBBR: There is neither a mechanism in place to sync .dts files into U-Boot or EDK2 source trees, nor are capsule updates implemented in U-Boot for easily deploying such bootloaders with new .dts sources or paths yet. And I can assure you that just getting users to dd the right bootloader can be difficult... Since DT forward and backward compatibility is often being neglected, for example with optional properties or renamed compatibles that break booting with previous drivers, new kernel versions often need updated Device Trees to make use of new/enhanced drivers. Therefore it is unfortunately often enough a necessity to load newer kernel-based .dtb files matching the kernel (as opposed to the dream of kernel-independent hardware descriptions) when working with the latest -rc or -next kernels at least. For examples of DTs needing updates, look no further than Linaro's 96boards - in case of hikey960/EDK2 GRUB is another layer where .dtb paths may be hardcoded, ditto for arm; and Armada was an example where the upstream bindings for the network IP changed incompatibly. DT overlays are another topic that is not making any progress upstream according to the ELCE BoF, so beyond the Raspberry Pi the only known working way to apply them is to write a U-Boot boot.scr script, which can either reuse $fdtcontroladdr DT or use the filename $fdtfile or hardcode one, the latter two of which would break with your renaming. So expect people to be using .dtb files, expect them to be affected by file movements to subdirectories here, and don't expect each user to understand or be able to fix things themselves if they fall apart as result of your changes and they suddenly no longer have Ethernet/Wifi. Regards, Andreas -- SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg)

6 years, 9 months

EBBR Agenda - 6 Dec 2018 - Meeting cancelled

by Grant Likely

I don't have an agenda for today. The one remaining blocker for 1.0 release is still open. I had hoped to get it written this past week, but haven't got it done yet. I did have a very productive meeting with Qualcomm last week. They have good feedback on the v0.6 draft, but I'll let them speak for themselves. I'm cancelling todays meeting, but I'll open the call anyway simply because it is so late that I'm sending this email. If you want to chat, feel free to dial in. If you do have a topic you want to discuss next week, please email me in the next week. g.

6 years, 9 months

EBBR Agenda - 8 Nov 2018

by Grant Likely

Any agenda items for todays call? Here is what I have so far: - Updates - SetVariable() - Compatibility statement - EBBR Plugfest? - Other Business Next week (15 Nov) we won't have a call, nor will there be a call on 29 Nov. g.

6 years, 10 months

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