Hi,
I just updated the technical report
<https://docs.google.com/document/d/1CLkhLRaz_zcCq44DLGmPZQFPbYHOC6nzPowaL0X…>
with a section on "Trusting DT" that is the result of my analysis of the
discussion we had (not what I presented).
Please comment, correct, update...
Cordially,
FF
--
François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group*
T: +33.67221.6485
francois.ozog(a)linaro.org | Skype: ffozog
Hi all,
The OpenAMP-remoteproc working group is looking forward to discuss OpenAMP bindings with the System DT working group & all others interested in System DT.
Best regards,
Nathalie C. Chan King Choy
Program Manager focused on Open Source & Community
Meeting number (access code): 145 853 2028
Meeting password: NgTwf4r8R$3
Monday, August 31, 2020
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Hi All,
We are interested in adopting EBBR as the boot specification for the
embedded RISC-V platforms.
We firmly believe that EBBR is a very well defined specification for
boot requirement and there
is no need for reinventing the wheel for RISC-V. Hence, this is a
thread to discuss all the requirements
for adding RISC-V to EBBR. Here is my current understanding. Please
correct me if I am wrong.
Logistic Requirement:
1. As per the contribution guidelines[1], patches should be sent to
boot-architecture(a)lists.linaro.org.
and the specification will be hosted under "ARM-software" Github.
I am hoping that introducing RISC-V
related changes are okay with the current maintainers.
2. The specification is licensed under Creative Commons. The RISC-V
related changes will refer to
some of the RISC-V specifications as well. AFAIK, there shouldn't
be an issue with that.
3. It should be okay to add other copyrights in addition to "Arm
Limited and Contributors".
Technical Requirement:
1. Software status:
a. UEFI support for RISC-V Linux kernel is already available in
the mailing list[2]. The targeted upstream
merge is the 5.10 merge window.
b. U-Boot already supports UEFI for RISC-V.
c. EDK2 upstreaming is currently under progress [3] as well.
Is it okay to start sending patches for EBBR RISC-V related changes
now or do we need to wait for EDK2 and Linux
kernel patches to be available upstream ?
2. RISC-V related sections in EBBR
a. UEFI:
Currently, RISC-V doesn't support a EFI_RESET_SYSTEM boot
service as firmware doesn't have a standard way
to reset the system. There is a proposal to add a system reset
function to Supervisor Binary Specification(SBI) which
can be mapped to EFI_RESET_SYSTEM by the firmware. Apart from
that, I believe RISC-V supports all UEFI boot and
run time services mandated by EBBR. Is it a blocker for RISC-V
EBBR compatibility?
b. RISC-V Multiprocessor Startup Protocol: This section will
contain the details of booting protocol for RISC-V and mandatory
RISC-V specifications that need to be implemented.
c. Firmware Storage: AFAIK, RISC-V platforms are already
compatible with this.
Please let me know if I missed something or oversimplified any
requirement. We want to make RISC-V compatible with EBBR
sooner than later and ready work on any missing pieces if any.
[1] https://github.com/ARM-software/ebbr/blob/master/CONTRIBUTING.rst
[2] https://lkml.org/lkml/2020/8/19/1252
[3] https://edk2.groups.io/g/devel/message/63831?p=,,,20,0,0,0::Created,,RISC-V…
[4] https://lists.riscv.org/g/tech-unixplatformspec/message/49?p=,,,20,0,0,0::r…
--
Regards,
Atish
Hi,
Yet another security issue surfaced yesterday, see this blog post about it
https://eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/
When I was reading it I cannot avoid seeing similarities to what I've tried
to raise in the DT(E)
discussions. I.e., firmware run-time exploits running after signatures have
been verified successfully
(slide 27, 28 [1]) can be devastating and therefore I've tried to suggest
that each component
verifies the DTB that it gets from the previous firmware component (slide
29, 30 [1]), alternatively
and probably better ... doing something like a measured boot (including
DTB's) where you compute
a running hash spanning across all firmware (+configuration) being loaded.
Some quotes from the blog post:
> Almost all signed versions of GRUB2 are vulnerable, meaning virtually
> every Linux distribution is affected.
We don't want to read something similar about DTS/DTB in the future.
> Additionally, as we will show in this blog post, a vulnerability in the
boot
> process that enables arbitrary code execution can allow attackers to
control
> the boot process and operating system, even when secure boot signatures
are verified.
Confirm my concerns.
> In the course of Eclypsium’s analysis, we have identified a buffer
overflow vulnerability
> in the way that GRUB2 parses content from the GRUB2 config file
(grub.cfg).
> Of note: The GRUB2 config file is a text file and typically is not signed
like other files
> and executables. This vulnerability enables arbitrary code execution
within GRUB2 and
> thus control over the booting of the operating system. As a result, an
attacker could
> modify the contents of the GRUB2 configuration file to ensure that attack
code is run
> before the operating system is loaded. In this way, attackers gain
persistence on the device.
Replace "GRUB2" with "DT" and "grub.cfg" with "*.dts/dtb" in the quote
above and
we have another potential future quote about DT security issues.
A solid, useable and robust solution for problems like this might be
complex to realize, but I
think it's worth continuing to look into what can be done, since it seems
risky to continue loading
and running "DT code" like we're doing in many places today (and it's not
only DT that is
subject to this, regular firmware suffers with the same kind of issues).
I.e., I'm going to
raise this again in future DT(E) calls.
[1]
https://docs.google.com/presentation/d/1CvKBBZ33ggzyhP2ub8iZ410I_KGrFjHftZL…
<https://eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/>
Regards,
Joakim
Attendees
François-Frédéric Ozog (Linaro)
Frank Rowand
Simon Glass (Google)
Ilias Apalodimas (Linaro)
Atish Patra (Western Digital)
Mark Brown (Arm)
Heinrich Schuchardt
CVS
Arnd Bergmann
Rob Herring (Arm)
Loic Pallardy (ST)
Poonam (NXP)
Ruchika
Loic Pallardy (ST)
Don Harbin(linaro)
Presentation
SLIDE 2
Francois: if we want authentication, we can’t do fix up
Simon: what is fix up? Can’t change DT or ok to change it?
Francois: can orchestrate transition, [edit as typing notes: changing
is not OK because you can’t identify the scope of change; adding a new
node may be acceptable - because scope is easy to frame]
Simon: code doing the fixup is signed , so it may be a signal that the
changes are OK; don’t know how to pass that to Linux. In principle you
should rely on signed code to make changes
Francois: [rephrasing at note editing] two trust models
1) implicit - trust because generating/updating code is signed
2) explicit - trust because you can check signature of the DT
Heinrich: if the DT comes from file system, it should be signed; for
DT embedded in signed code: no need to have a signature; signature for
things from file but not from memory [at writing notes, I understand
this as a DT fragment generated by FT-A in memory does not need to be
signed]
SLIDE 3
Francois: cold-plug by U-Boot, hotplug by OS
Francois: Board DTB + cape DTBo + cape_on_board DTBo (pin muxing
config, irq config…)
Frank: Device removal triggers DT correspond node(s) removal? If so,
then we should limiting a single device per overlay
Francois: yes. It is also connected to device assignment. There should
be a way to identify all nodes of a device in DT to actually simplify
device assignment (to be discussed later in the deck)
SLIDE 4
Lets use a special config DTBo (chosen…)
Let’s get the parameters out of DT in local OS config (or worst case,
in that config DTBo)
Rob: problem with systems with loadable modules
Arnd: can be passed on command line
Rob: Greg KH say: don’t add module parameters
Arnd: device specific parameters should be done via sysfs/ioctl;
driver wide parameters could be as module parameters or boot command
line
Frank or it could be a “chosen”
[editig time] Francois: for Linux, can we organize module parameters
in modules.d are parsed when modules are statically linked?
Let’s not use DT when we can avoid (OP-TEE bus to discover TAs)
SLIDE 5
Francois: wherever we choose, we shall ensure backward compatibility
SLIDE 6
DTB=base board + 1 DTBo per device
Statically merge DTB + DTBos at compile time and keep metadata about
the merge in a section of the new DT file format.
SLIDE 7
Arnd/Simon: Right now the Android boot loader merges DTB/DTBos and
passes one DTB to the kernel
Simon: ChromeOS has a FIT image with multiple DTs, it selects one to pass to OS
Arnd/Ilias: FIT is only understood by U-Boot
Francois: wherever we choose, we shall ensure backward compatibility
Arnd: It’s simpler to have a single DTB for the kernel
Early kernel is not really powerful
There are security advantages in signed DTBos
Francois: I think the key question is decide on a model. Allow
bootloaders to change the DTB and rely on signed DTBos?
Simon: is either or ? [explicit vs implicit trust models], what is the
threat model?
Francois: yes, I think so.
Heinrich: problem is wrong voltage in DT results in destroying the board
Arnd: steal sensitive data
Ilias: DoS can become a problem
Ilias: signing per device (key mgmt complexity) ? or per device model
(can compromise all devices of a model)?
Francois: Who signs what is also a fundamental concept, because there
might be different signing authorities
Loic: That’s the current case wit ST devices
Arnd: There’s 3 options here:
Kernel with embedded DTB, if the kernel signature is checked, the DTB
does not need to be checked
The bootloader loads the kernel from a disk
Nothing is checked
Checking one of those makes no sense
Simon: we have to be careful in not tying ourselves in a knot. There
is *no* bidirectional root of trust. The model is that trust is built
starting from the root of trust, the next level implicitly trusts the
level that loaded it.
Mark Brown: DT is used with EDK2
Loic: there is no direct boot from U-Boot to kernel, it is vouched by OP-TEE.
security of co-processors requires the same model
Hardware firewall (device and memory) can be leveraged to ensure full security
DTE Project information portal:
https://collaborate.linaro.org/display/DTE/DTE+Progress+Updates
Security presentation: (listed in the portal, but copied here for
simple access):
https://docs.google.com/presentation/d/1CvKBBZ33ggzyhP2ub8iZ410I_KGrFjHftZL…
Hi,
I think we have gathered enough knowledge in the Technical Report to
try architecting DT evolution technologies.
To that end, I'll kick start discussion with:
https://docs.google.com/presentation/d/1jACxdO-3fDzSk5MEMUEmAu0iMjtp9Td7Xbb…
Everyone has commenter capabilities in the document, so please use it.
I am sure most of the proposals cannot be "decided on" during the
call. But I'd like to come to a conclusion on one topic: whether or
not fix ups are allowed. If we introduce signature of any form with
DTB, then I believe fixups are not possible anymore.
Cheers
--
FF
Hi all,
The notes from today's call can be found on the OpenAMP Wiki at https://github.com/OpenAMP/open-amp/wiki/System-DT-Meeting-Notes-2020#2020J…
The action items are:
* Stefano to share slides
* Xilinx and ST to discuss interconnect binding, considering that it could be expanded beyond QoS, and review Rob's earlier feedback to Benjamin on pin control
* Stefano to check if configuration interface assumes that IDs are global
* Stefano to work with Bruce to prototype something w/ Lopper to generate a bus firewall configuration table
* Stefano to present openamp-remoteproc binding for System DT at next call
@ Stefano, Loic, Rob, Ilias, Tomas (and anyone else who spoke, if I missed you): Please check if there are any errors or important omissions in what I captured for your parts. You can make corrections directly in the wiki page.
Thanks & regards,
Nathalie C. Chan King Choy
Program Manager focused on Open Source and Community
[Invitation going out to both the sytem-dt list and the boot-architecture list, based on recommendation from Francois]
Hi all,
It has been a while since our last call, because work was happening on the 4th action item below. Now, there are some updates to present.
The notes from the previous call can be found on the OpenAMP wiki at this link:
https://github.com/OpenAMP/open-amp/wiki/System-DT-Meeting-Notes-2020
Action items from the previous call:
* Nathalie sync up w/ Francois about who should be invited to System DT call (some individuals at DTE call didn't get this invitation)
* Stefano to go back & discuss w/ Xilinx XMPU expert.
* Stefano: Revisit wording of IDs
* Stefano & Tomas to sync-up with Loic & Benjamin. Target for next System DT call to discuss how the 2 proposals combine. Include description of the use cases you're giving solution for.
For info about the system-dt list, link to the archives, to unsubscribe yourself, or
for someone to subscribe themselves, visit:
https://lists.openampproject.org/mailman/listinfo/system-dt
For information about the System Device Trees effort, including a link to
the intro presentation from Linaro Connect SAN19:
https://github.com/OpenAMP/open-amp/wiki/System-Device-Trees
Best regards,
Nathalie C. Chan King Choy
Program Manager focused on Open Source and Community
===================
Nathalie Chan King Choy is inviting you to a scheduled Zoom meeting.
Topic: System DT call - July
Time: Jul 20, 2020 08:00 AM Pacific Time (US and Canada)
Join Zoom Meeting
https://us02web.zoom.us/j/89143577824
Meeting ID: 891 4357 7824
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Hi,
Here are the notes from our last meeting.
(For next calls, it would be nice people take some notes in the shared
scratch document so that we increase quality of them)
Attendees
Tom Rini
Joakim Bech (Linaro)
François-Frédéric Ozog (Linaro)
Ilias Apalodimas (Linaro)
Mark Brown (Arm)
Heinrich Schuchardt
Priyanka Jain (NXP)
Jens Wiklander (Linaro)
Arnd Bergmann
CVS
Atish Patra (Western Digital)
Grant Likely (Arm)
Etienne Carriere (ST)
====================================
I - RISC-V
Atish from Western Digital has a 4 developer team on. Focus on
standardized boot flows:
- U-Boot SPL + U-Boot.
- coreBoot + EDK2
====================================
II - Technical report github
Atul volunteered
FF: What format to use ? RST? MD? Other?
Heinrich: RST and MD are rendered by github.
====================================
III - Technical report outline and content updates
A proposal to be made so that a minimal UEFI set of requirements is
defined with DT support.
Frank: Should not put DT spec in the UEFI forum
FF: this is not the goal, the goal is to get references to DT in UEFI
Need to ensure we have terminology that can be applied to all
architectures (for instance Arm+TFA+U-Boot and RISC-V+U-Boot
SPL+U-Boot).
Please make proposals for content including new sections for the use cases.
====================================
IV- Overlays presentation
Franks Presentation notes:
https://elinux.org/Frank%27s_Evolving_Overlay_Thoughtshttps://elinux.org/images/0/03/Elce_2018_dt_bof.pdfhttps://elinux.org/Device_Tree_Reference -> OverLays
Overlay made simple with DTC extensions: use a reference to define the
place in the tree where the update is to be made:
&{/path/to/node} { <overlay definition> }
Use cases:
Hot swap
Expansion slots (beaglebone)
FPGAs (load from kernel to FPGA; led by Altera/Xilinx)
Not too dynamic, in particular because there are still memory leaks
Use of “apply overlay by the bootload” helps reducing the number of
DTS/DTB files to deal with.
plugable CPU: overlay is a solution
few terms to define/standardise/clarify by frank:
Cold-swap = ? < describe the actual use-case in simple terms >
Hot-swap = ? < describe the actual use-case in simple terms >
Real hot-swap will be difficult to support.
Another use case for “hot-swap” is a developer helper to change
parameter “dynamically” to avoid a full reboot.
FF: DT event may be a wrong way to deal with dynamism: using bus
events to trigger changes seem more natural
Grant: event code is fragile, prefer pre-boot control
Hi,
I have updated the document to reflect what I heard from the remainder
of the last call. Please have a look and comment.
https://docs.google.com/document/d/1CLkhLRaz_zcCq44DLGmPZQFPbYHOC6nzPowaL0X…
If you volunteer to edit content, please ask me and I'll give you edit
rights on the document.
Shall we make a github backed document? If so, any volunteer to make it happen?
Agenda for June 24th:
- DT Overlay status presentation by Frank Rowand.
- Document review and trying to close all comments.
Cordially
--
FF
Hi,
Trusted OSes such as OP-TEE or QSEE are using SMC yielding function
numbers in the 0x32000000-0x3200006F range. The SMC calling
conventions are specified in DEN0028 which has currently three
versions (see below).
To the best of my understanding, the use of this range is:
- compliant with version a
- acceptable with version b
- somewhat contradicting with version c
version a analysis:
table 6.1 states that the trusted OS standard calls should be in the
range "0x02000000-0x7FFFFFFF", so the selected range is good. Section
2.1 that defines a bit structure for function numbers for both
yielding and fast calls and the range is compatible. The range covered
by table 6.1 for Trusted OS calls is however much bigger that the bit
structure definition. As a result a 0x02000000 call is a yielding
Trusted OS call as per table 6.1 but a Yielding SiP call as per
section 2.1.
version b analysis:
table 6.2 states that the trusted OS yielding calls should be in the
range "0x02000000-0x1FFFFFFF" and that the range
"0x20000000-0x7FFFFFFF" is "reserved for future expansion of Trusted
OS Yielding Calls". So the range is acceptable but poorly selected.
There is the same inconsistency as version a when it comes to
qualifying a 0x02000000 call: table 6.2 says it is a Trusted OS
yielding call, section 2.5 says it is a yielding SiP call.
version c analysis:
section 2.5.1 now clearly states that the bit structure is only for
Fast calls. and both section 2.52 and table 6.2 state that Trusted OS
calls should be in the range "0x02000000-0x1FFFFFFF". both section
2.5.2 and 6 qualify the 0x02000000 call as a Trusted OS yielding
call.
I think that version a and b have inconsistent between chapter 2 and
6. Version c brings internal consistency but seems to be not in
alignment with best practices.
I guess there is a need to both address internal document
inconsistency and better reflect existing products.
Any thoughts?
-FF
version a:
https://drive.google.com/file/d/1OclQZk0o28n5ZUIYeTuFICbLiGWzOvxH/view?usp=…
version b: https://static.docs.arm.com/den0028/b/ARM_DEN0028B_SMC_Calling_Convention.p…
version c:
https://static.docs.arm.com/den0028/c/Q1-ARM-DEN-0028_SMC_Calling_Conventio…
Hello Francois,
in our last meeting you suggested to investigate deeper what meaning
modularization in device trees could mean.
One example I have seen is the definition of memory mappings for PCIe.
If for you example you look in the device tree of the Raspberry Pi 4 you
can find that there is an entry:
pcie@7d500000 {
ranges = <
0x2000000 0x00 0xf8000000 0x06 0x00 0x00 0x4000000>;
};
The ranges property defines the mapping
MEM 0x600000000..0x603ffffff -> 0xf8000000
and thereby the address and size of the memory windows used for
communication.
On some boards e.g. the MacchitoBin you have multiple platform devices
each with its own ranges definitions. Here are the values in May 2019:
pcie@f2600000 {
ranges = <
0x81000000 0x0 0xf9000000 0x0 0xf9000000 0x0 0x10000
0x82000000 0x0 0xf6000000 0x0 0xf6000000 0x0 0xf00000>;
}
pcie@f2620000 {
ranges = <
0x81000000 0x0 0xf9010000 0x0 0xf9010000 0x0 0x10000
0x82000000 0x0 0xf7000000 0x0 0xf7000000 0x0 0xf00000>;
}
pcie@f2640000 {
ranges = <
0x81000000 0x0 0xf9020000 0x0 0xf9020000 0x0 0x10000
0x82000000 0x0 0xf8000000 0x0 0xf8000000 0x0 0xf00000>;
}
On my MacchitoBin the GPU card was not usable because the memory window
was too small to create the required BARs. Changing the window size and
location solved the problem, commit d3446b266a8c ("arm64: dts: marvell:
mcbin: enlarge PCI memory window").
The problem with the current way in qhich PCI devices are declared is
that they do not indicate requirements and capabilities and let the
software figure out a good mapping. But instead fixed mappings are
hard-coded into the device-tree.
So for me this would be one element of DT modularization:
The description of a device should provide capabilities and requirements
and avoid fixed software settings.
Best regards
Heinrich
Address comments from Heinrich Schuchardt:
- Typo fixes
- Be specific to say "Devicetree Blob"
- Add comment on rationale for choosing EfiACPIReclaimMemory for DTB
Cc: Heinrich Schuchardt <xypron.glpk(a)gmx.de>
Signed-off-by: Grant Likely <grant.likely(a)arm.com>
---
source/chapter2-uefi.rst | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst
index c9c0101..066fefb 100644
--- a/source/chapter2-uefi.rst
+++ b/source/chapter2-uefi.rst
@@ -81,9 +81,9 @@ A UEFI system that complies with this specification may provide the additional
tables via the EFI Configuration Table.
Compliant systems are required to provide one, but not both, of the following
-tables.
+tables:
-- An Advanced Configuration and Power Interface [ACPI]_ table, or
+- an Advanced Configuration and Power Interface [ACPI]_ table, or
- a Devicetree [DTSPEC]_ system description
EBBR systems must not provide both ACPI and Devicetree
@@ -96,11 +96,13 @@ Devicetree
^^^^^^^^^^
If firmware provides a Devicetree system description then it must be provided
-in Flattened Devicetree (DTB) format version 17 or higher as described in
+in Flattened Devicetree Blob (DTB) format version 17 or higher as described in
[DTSPEC]_ § 5.1.
The following GUID must be used in the EFI system table ([UEFI]_ § 4)
to identify the DTB.
The DTB must be contained in memory of type EfiACPIReclaimMemory.
+EfiACPIReclaimMemory was chosen to match the recommendation for ACPI
+tables which fulfill the same task as the DTB.
.. code-block:: c
--
2.20.1
I'd like to do a point release of EBBR in the near future. There is an
important change to how RuntimeServicesSupported is described in the
UEFI spec that needs to be adjusted in EBBR, and the DTB UUID was
missing. The rest of the changes are minor editorial and typo fixes.
I've tagged v1.0.1-rc1 in github for review. Full diff is below. Please
review and comment.
Thanks,
g.
---
.travis.yml | 82 +++++++++++++++++------------------------
CONTRIBUTING.rst | 23 +-----------
source/chapter2-uefi.rst | 40 +++++++++++++++++---
source/chapter3-secureworld.rst | 6 +--
source/index.rst | 3 ++
source/references.rst | 10 ++---
6 files changed, 81 insertions(+), 83 deletions(-)
---
diff --git a/.travis.yml b/.travis.yml
index 3688a67..4a63cb0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,63 +1,49 @@
sudo: false
dist: trusty
-
cache:
apt: true
-
env:
global:
- - SPHINXBUILD=~/.local/bin/sphinx-build
- - DIFF_COMMIT=v0.5
-
+ - SPHINXBUILD=~/.local/bin/sphinx-build
+ - secure: 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
git:
depth: false
-
addons:
apt:
packages:
- - python-pip
- - latexmk
- - libalgorithm-diff-perl
- - texlive
- - texlive-latex-extra
- - texlive-humanities
- - texlive-generic-recommended
- - graphviz
- - texlive-generic-extra
-
+ - python-pip
+ - latexmk
+ - libalgorithm-diff-perl
+ - texlive
+ - texlive-latex-extra
+ - texlive-humanities
+ - texlive-generic-recommended
+ - graphviz
+ - texlive-generic-extra
install:
- - pip install --user mako
- - pip install --user Sphinx
-
-before_script:
- - wget https://github.com/ftilmann/latexdiff/releases/download/1.2.1/latexdiff-1.2…
- - tar xvf latexdiff-1.2.1.tar.gz
- - export PATH=$PWD/latexdiff-1.2.1/:$PATH
-
+- pip install --user mako
+- pip install --user Sphinx
script:
- - make latexpdf
- - make html
- - make singlehtml
-
+- make latexpdf
+- make html
+- make singlehtml
before_deploy:
- - cp build/latex/ebbr.pdf build/ebbr-$TRAVIS_TAG.pdf
-
+- cp build/latex/ebbr.pdf build/ebbr-$TRAVIS_TAG.pdf
deploy:
- - provider: releases
- prerelease: true
- api_key:
- secure: 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
- file_glob: true
- file:
- - "build/ebbr-*.pdf"
- skip_cleanup: true
- on:
- tags: true
- branch: master
- - provider: pages
- github_token: $GITHUB_TOKEN
- local_dir: "build/singlehtml"
- skip_cleanup: true
- on:
- branch: master
-
+- provider: releases
+ prerelease: true
+ api_key:
+ secure: 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
+ file_glob: true
+ file:
+ - build/ebbr-*.pdf
+ skip_cleanup: true
+ on:
+ tags: true
+ branch: master
+- provider: pages
+ github_token: "$GITHUB_TOKEN"
+ local_dir: build/singlehtml
+ skip_cleanup: true
+ on:
+ branch: master
diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index a5643a3..7021f0f 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -8,35 +8,14 @@ Anyone may contribute to the EBBR project.
Contributions are licensed under CC-BY-SA-4.0_ and must be made with a
Developer Certificate of Origin (DCO_) attestation as described below.
-EBBR discussion uses the boot-architecture_ and arm.ebbr-discuss mailing lists.
-The 'official' list is arm.ebbr-discuss, but the list archives are not
-yet public, so boot-architecture_ is being used to keep everything in
-the open.
+EBBR discussion uses the boot-architecture_ mailing list.
* boot-architecture(a)lists.linaro.org
-* arm.ebbr-discuss(a)arm.com
Past discussions can be found in the boot-architecture-archive_.
We use the IRC channel `#ebbr`_ on OFTC_.
-There is a bi-weekly conference call to discuss EBBR topics on the 2nd
-and 4th Tuesday of the month at 15:00 UTC/BST, 7:00 PST/PDT, 23:00/22:00 CST
-(following UTC/BST daylight savings time shifts).
-Anyone is welcome to join.
-
-- Online meeting: https://arm-onsite.webex.com/meet/gralik01
-- Phone
-
- - 1-408-792-6300 Call-in toll number (US/Canada)
- - 1-877-668-4490 Call-in toll-free number (US/Canada)
- - 44-203-478-5285 Call-in toll number (UK)
- - 08-002061177 Call-in toll-free (UK)
- - More access numbers: webex-global-numbers_
-- Access code: 809 053 990
-
-.. _webex-global-numbers: https://arm-onsite.webex.com/cmp3300/webcomponents/widget/globalcallin/glob…
-
DCO Attestation
---------------
diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst
index f6a5802..c9c0101 100644
--- a/source/chapter2-uefi.rst
+++ b/source/chapter2-uefi.rst
@@ -9,7 +9,7 @@ platforms.
UEFI Version
============
-This document uses version 2.7 of the UEFI specification [UEFI]_.
+This document uses version 2.8 Errata A of the UEFI specification [UEFI]_.
UEFI Compliance
===============
@@ -86,12 +86,41 @@ tables.
- An Advanced Configuration and Power Interface [ACPI]_ table, or
- a Devicetree [DTSPEC]_ system description
-As stated above, EBBR systems must not provide both ACPI and Devicetree
+EBBR systems must not provide both ACPI and Devicetree
tables at the same time.
Systems that support both interfaces must provide a configuration
mechanism to select either ACPI or Devicetree,
and must ensure only the selected interface is provided to the OS loader.
+Devicetree
+^^^^^^^^^^
+
+If firmware provides a Devicetree system description then it must be provided
+in Flattened Devicetree (DTB) format version 17 or higher as described in
+[DTSPEC]_ § 5.1.
+The following GUID must be used in the EFI system table ([UEFI]_ § 4)
+to identify the DTB.
+The DTB must be contained in memory of type EfiACPIReclaimMemory.
+
+.. code-block:: c
+
+ #define EFI_DTB_GUID \
+ EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5, \
+ 0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0)
+
+Firmware must have the DTB resident in memory and installed in the EFI system table
+before executing any UEFI applications or drivers that are not part of the system
+firmware image.
+Once the DTB is installed as a configuration table,
+the system firmware must not make any modification to it or reference any data
+contained within the DTB.
+
+UEFI applications are permitted to modify or replace the loaded DTB.
+System firmware must not depend on any data contained within the DTB.
+If system firmware makes use of a DTB for its own configuration,
+it should use a separate private copy that is not installed in the
+EFI System Table or otherwise be exposed to EFI applications.
+
UEFI Secure Boot (Optional)
---------------------------
@@ -111,7 +140,7 @@ during both boot services and runtime services.
However, it isn't always practical for all EFI_RUNTIME_SERVICES functions
to be callable during runtime services due to hardware limitations.
If any EFI_RUNTIME_SERVICES functions are only available during boot services
-then firmware shall provide the global `RuntimeServicesSupported` variable to
+then firmware shall provide the `EFI_RT_PROPERTIES_TABLE` to
indicate which functions are available during runtime services.
Functions that are not available during runtime services shall return
EFI_UNSUPPORTED.
@@ -148,7 +177,7 @@ Firmware shall not create runtime mappings, or perform any runtime IO that will
conflict with device access by the OS.
Normally this means a device may be controlled by firmware, or controlled by
the OS, but not both.
-e.g. If firmware attempts to access an eMMC device at runtime then it will
+E.g. if firmware attempts to access an eMMC device at runtime then it will
conflict with transactions being performed by the OS.
Devices that are provided to the OS (i.e., via PCIe discovery or ACPI/DT
@@ -202,7 +231,8 @@ If a platform does not implement modifying non-volatile variables with
SetVariable() after ExitBootServices(),
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.
+via the `RuntimeServicesSupported` value in the `EFI_RT_PROPERTIES_TABLE`
+as defined in [UEFI]_ § 4.6.
EFI applications can read `RuntimeServicesSupported` to determine if calls
to SetVariable() need to be performed before calling ExitBootServices().
diff --git a/source/chapter3-secureworld.rst b/source/chapter3-secureworld.rst
index 4e9fa61..9c51bca 100644
--- a/source/chapter3-secureworld.rst
+++ b/source/chapter3-secureworld.rst
@@ -1,8 +1,8 @@
.. SPDX-License-Identifier: CC-BY-SA-4.0
-******************************
-Priviledged or Secure Firmware
-******************************
+*****************************
+Privileged or Secure Firmware
+*****************************
AArch32 Multiprocessor Startup Protocol
=======================================
diff --git a/source/index.rst b/source/index.rst
index 9bc4a09..7a5ded9 100644
--- a/source/index.rst
+++ b/source/index.rst
@@ -45,6 +45,9 @@ Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.
31 March 2019 1.0 - Remove unnecessary UEFI requirements
appendix
- Allow for ACPI vendor id in firmware path
+ 1 June 2020 1.0.1-rc1 - Update to UEFI 2.8 Errata A
+ - Specify UUID for passing DTB
+ - Typo and editorial fixes
================= ========= =============================================
.. toctree::
diff --git a/source/references.rst b/source/references.rst
index a12c1a2..1eb0509 100644
--- a/source/references.rst
+++ b/source/references.rst
@@ -8,8 +8,8 @@
<https://github.com/devicetree-org/devicetree-specification/releases/tag/v0.2>`_,
`Devicetree.org <https://devicetree.org>`_
-.. [LINUXA64BOOT] `Linux Documentation/arm64/booting.txt
- <https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tre…>`_,
+.. [LINUXA64BOOT] `Linux Documentation/arm64/booting.rst
+ <https://www.kernel.org/doc/html/latest/arm64/booting.html>`_,
Linux kernel
.. [PSCI] `Power State Coordination Interface Issue C (PSCI v1.0)
@@ -20,6 +20,6 @@
<https://static.docs.arm.com/den0044/b/DEN0044B_Server_Base_Boot_Requirement…>`_
8 March 2016, `Arm Limited <http://arm.com>`_
-.. [UEFI] `Unified Extensable Firmware Interface Specification v2.7A
- <http://www.uefi.org/sites/default/files/resources/UEFI%20Spec%202_7_A%20Sep…>`_,
- August 2017, `UEFI Forum <http://www.uefi.org>`_
+.. [UEFI] `Unified Extensable Firmware Interface Specification v2.8 Errata A
+ <https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_A_Feb14.pdf>`_,
+ February 2020, `UEFI Forum <http://www.uefi.org>`_
On Wed, Mar 11, 2020 at 01:42:36PM +0100, Francois Ozog wrote:
> On Wed, 11 Mar 2020 at 12:45, Daniel Thompson <daniel.thompson(a)linaro.org>
> wrote:
>
> > On Wed, Mar 11, 2020 at 11:20:17AM +0100, Francois Ozog wrote:
> > > On Wed, 11 Mar 2020 at 07:48, Heinrich Schuchardt <xypron.glpk(a)gmx.de>
> > wrote:
> > > > On 3/11/20 12:04 AM, Heinrich Schuchardt wrote:
> > > > In the expert mode of gdisk there is command 'j' for moving the GPT
> > > > Partition Entry Array to an arbitrary sector. This will protect the
> > area
> > > > between the GPT header and the GPT Partition Entry Array from being
> > used
> > > > for a partition. The same can be done with parameter -j of sgdisk.
> > > >
> > > > Furthermore gdisk supports creating a hybrid MBR. This allow to have
> > > > GUID partition table and a MBR partion table at the same time where the
> > > > MBR partition table mirrors up to three GPT partitions and the fourth
> > > > MBR partition is used to protect the GUID partition table.
> > > >
> > > > So requiring GPT and having boards only supporting booting from an MBR
> > > > partition (like the Raspberry) seems not to be exclusive.
> > > >
> > >
> > > That sounds like a great solution!
> >
> > The last time we discussed this there was *very* strong opposition
> > during meetings to hybrid partitioning and IIRC language was added to
> > the spec to prohibit it.
> >
> > Hybrid partitioning is a problem because it imposes to difficult to meet
> > constraints on partitioning tools provided by the operating system.
> >
> > In other words if we permit hybrid partitioning in order that boot code
> > can find the firmware then the operating system would inherit a duty to
> > not to screw up the firmware loading when it modifies the partition
> > tables. It is hard to express how the OS should go about that.
> >
> > Hence the current approach where we accept that MBR partitioning
> > offers an inferior feature set to GPT.
> >
> >
> We have the following cases:
>
> - FW compatible with GPT (I mean firmware can be searched based on
> GUID partition)
> Ok
>
> - FW that uses offsets and can be positioned at LBA >= 33
> Ok
> Need to define a protective partition
>
> - FW that uses offsets and can be positioned such that space between LBA-2
> and LBA-33 is used.
> Ok in theory as the header states where the partition entries location is
> specified in a GPT_HEADER "Starting LBA of array of partition entries".
> Linux kernel properly loads the partition entries if we push them after
> 16MB.
>
> read_lba <https://elixir.bootlin.com/linux/latest/ident/read_lba>(state,
> le64_to_cpu <https://elixir.bootlin.com/linux/latest/ident/le64_to_cpu>(gpt->partition_entry_lba)
>
> But I bet 2 is hardcoded in many tools...
Agree... but that's "just bugs" and I suspect we could get >90% test
coverage for Linux systems just by checking util-linux (and the kernel
itself). Maybe for extra style points also check on of the BSDs.
> - FW that supposes LBA-1 (macchiatobin the firmware blob that contain TF-A
> must be here)
> In theory OK as Linux will detect bad signature and use the alternate GPT
In the current spec this case isn't materially different to firmware
whose boot ROM parses the MBR to load extra code (which wasn't listed
above). In both cases the system would be expected to adopt MBR and
create protective partitions for the firmware (and accept that the
protective partition is vulnerable to damage by auto-partitioning
installers).
Having said is this really relevant for MacchiatoBin? Why put EBBR
firmware onto shared media? I thought MacchiatoBin could boot from the
4MB SPI NOR.
Daniel.
Hi,
I have observed a spike in DT presentations at events in 2018 and a
relative smaller set in 2019.
Many discussions raise a lot of good points, there are lists of things
to solve or proposals in various sites but there is no clear path to a
widely acceptable solution.
It feels like the traditional model of "contribute code first" reaches
its limits here: Device Tree is not just a device tree. It is a
pivotal piece of information manipulated by too many components from
Trusted Firmware A to Mac OSX and U-boot. And there are many
legitimate "owners" of pieces of the DT...
We need to find a way to build consensus across projects. Mail
discussions are good but I feel this does not fully help getting
closer to having up streamed code and specs into projects such as (and
not limited to):
- Trusted Firmware
- OP-TEE
- Hafnium
- U-Boot
- Linux
- Android
- FreeBSD
- DeviceTree
- EBBR
- Firmware Framework A
- Parsec
To that end, what about collectively building a Technical Report with
a number of editors in charge of different sections?
An example outline could be:
- the problems we try to solve (and what is outside of scope)
. board diversity handling (build/boot/runtime)
. cape/hat/FPGA handling (build/boot/runtime)
. product value chain handling (soc vendor/product vendor/sw vendor...)
. trust of DT
. device assignment to application or VM
- DT evolution
. actors (UML meaning)
. responsibility boundaries (signatures...)
. DTB format evolution
. DTBo
. DT at build time for many upstream projects
- cross project incremental roadmap highlights
. introduce DT signature
Of course the Technical Report shall be supported by different PoCs on
many topics such as DTB format so that the architecture is future
proof and we can start small.
What are your views?
Cheers
FF
Hi,
Following implementation (or work towards) of EBBR 1.0 + UEFI Secure
boot + UEFI update capsule we learnt a lot.
Here are some topics that may need some clarification on the EBBR
specs and It looks timely to start working on EBBR evolution.
0.1 - EBBR goal
May be a reassessment on the "for what" the specification is built.
Following all the discussions with prominent industry players, I start
to think that limiting the constraints to be EBBR compliant may become
counter productive. There will be both EBBR non compliant and EBBR
compliant systems. This is inevitable. But EBBR exist for a number of
use cases in a number of markets. The value of EBBR is consistent
behavior across those.
Maximising number of EBBR compliant systems without stating use case
parameters ( "why" and "for what") may not be the best goal.
Out of things to be more explicit are supported secure boot flows
(with/without shim+grub or direct). Some vendors require shim+grub
while industry players want the exact opposite: nothing but UEFI. This
drivers a number of requirements in terms of UEFI protocols needed
0.2 - normative text
The normative section shall be stated clearly: is " 1.2. Guiding
Principles" normative?
IETF and ETSI have different language conventions to express
absolutely mandated and various levels of optionality. This spec may
be red by Telecom people or Linux people. Their interpretation may be
erroneous on words such as "shall" (ETSI "SHALL" = "IETF "MUST"). The
language need to be explicit.
I - protective offsets
EBBR 1.0 states in "4.1. Partitioning of Shared Storage" that
"Automatic partitioning tools (e.g. an OS installer) must not create
partitions within the first 1MiB of storage, or delete, move, or
modify protective partition entries."
StandaloneMM is 2.5MB by itself with U-Boot being over 1MB without the
variable rework done and update capsules. 4MB seems the minimum. 8MB
to get margin and 16MB for A/B scheme.
EBBR same paragraph also states:
"Automatic partitioning tools (e.g. an OS installer) must not create
partitions within the first 1MiB of storage, or delete, move, or
modify protective partition entries. Manual partitioning tools should
provide warnings when modifying protective partitions or creating
partitions within the first 1MiB."
is it expected that Linaro upstreams changes in installation tools,
partition tools to conform to this (with updated to be agreed
minimum)?
II - identifying partitions
Having two EFI partitions defined with EFI_GUID need a precise
behaviour defined: boot with first or boot with second.
Shall we have a EFI_GUID_ALT defined for A/B partition schemes?
If not, the BootXXX variables should be used as selector?
We lean towards BootXXX variables and not defining a new GUID. But
this would mean explicit behavior to be stated in case of lack of
BootXXX.
I think GPT volume mirroring should be used in conjunction with A/B:
A/B to recover version failures with current hardware, surrounding
software; mirroring to protect against storage failures.
Is there any recommendation on mirrored EFI volumes handling ?
III - 32 bits
are there any 32 bits specific considerations to be added?
IV - UEFI_RNG_PROTOCOL
Following my view in 0) I think this shall be made mandatory
Linaro has upstreamed this in U-Boot and started to implement
additional hardware drivers.
KASLR is thus functional in 64 bits and will be in 32bits.
V - UEFI SecureBoot
Following my view in 0) I think this shall be made mandatory
UEFI SecureBoot is not mentioned in section 2.6 so we need to clarify
what needs to be implemented.
In particular, we need to implement EFI_LOAD_FILE2_PROTOCOL for initrd
signature checking.
VI - UEFI update capsules
Following my view in 0) I think this shall be made mandatory
Section 2.6 of UEFI spec 2.7 mentions
At some point in time we will need to propose UEFI specification update for:
- anti-bricking anti rollback expected behavior
- abstract capsules for "start transaction", "commit", "rollback" when
we will be dealing with system wide transactional updates.
There is probably a lot to state here but I am just starting the discussion.
VII - UEFI watchdog
Following my view in 0) I think this shall be made mandatory
In addition to its definition, it should also integrate consistent
parameters to define total duration covered as well as number of
failed consecutive updates to be triggered as well as how it is
delivered (powercycle, NMI, secureIRQ...)
Cheers
--
François-Frédéric
Hello Francois,
in a previous post I already mentioned some device tree fix-ups that
U-Boot is applying.
One new fix-up I found is the "cpu-release-addr" property in CPU nodes
if the "enable-method" is "spin-table". - Before seeing this I never
imagined CPU nodes to be dynamically filled.
I think for our DTE discussion on signed device trees it would be
valuable to know which parts of the device-tree are dynamically created.
Where would be a good location to collect this information?
Would the topic of dynamic parts of device trees deserve two slides on
our next meeting?
Best regards
Heinrich
On 5/20/20 7:49 PM, François Ozog wrote:
>
>
> On Wed, 20 May 2020 at 19:30, Daniel Thompson
> <daniel.thompson(a)linaro.org <mailto:daniel.thompson@linaro.org>> wrote:
>
> On Wed, May 20, 2020 at 07:00:53PM +0200, François Ozog wrote:
> > On Wed, 20 May 2020 at 18:39, Daniel Thompson
> <daniel.thompson(a)linaro.org <mailto:daniel.thompson@linaro.org>>
> > wrote:
> >
> > > On Tue, May 19, 2020 at 03:29:01PM +0100, Grant Likely wrote:
> > > > On 11/03/2020 16:42, Daniel Thompson wrote:
> > > > > On Wed, Mar 11, 2020 at 01:42:36PM +0100, Francois Ozog wrote:
> > > > > > We have the following cases:
> > > > > >
> > > > > > - FW compatible with GPT (I mean firmware can be searched
> based on
> > > > > > GUID partition)
> > > > > > Ok
> > > > > >
> > > > > > - FW that uses offsets and can be positioned at LBA >= 33
> > > > > > Ok
> > > > > > Need to define a protective partition >>
> > > > > > - FW that uses offsets and can be positioned such that
> space between
> > > LBA-2
> > > > > > and LBA-33 is used.
> > > > > > Ok in theory as the header states where the partition entries
> > > location is
> > > > > > specified in a GPT_HEADER "Starting LBA of array of partition
> > > entries".
> > > > > > Linux kernel properly loads the partition entries if we
> push them
> > > after
> > > > > > 16MB.
> > > > > >
> > > > > > read_lba
> <https://elixir.bootlin.com/linux/latest/ident/read_lba
> > > >(state,
> > > > > > le64_to_cpu <
> > > https://elixir.bootlin.com/linux/latest/ident/le64_to_cpu
> > > >(gpt->partition_entry_lba)
> > > > > >
> > > > > > But I bet 2 is hardcoded in many tools...
> > > > >
> > > > > Agree... but that's "just bugs" and I suspect we could get
> >90% test
> > > > > coverage for Linux systems just by checking util-linux (and
> the kernel
> > > > > itself). Maybe for extra style points also check on of the BSDs.
> > > >
> > > > It is worth stepping back from the details to take a look at
> the intent.
> > > The
> > > > purpose of this entire section of EBBR is to describe how
> firmware and
> > > the
> > > > OS can co-exist on the same media device. In broad strokes it
> means if
> > > > firmware is stored on the block device, then the OS must
> constrain how it
> > > > uses the device.
> > > >
> > > > On platforms with separate firmware storage (e.g., SPI flash
> or UFS boot
> > > > partitions) this isn't an issue. The OS can blow away
> everything on the
> > > disk
> > > > and recreate it.
> > > >
> > > > But when it is an issue, the rules need to lay down what regions
> > > (offsets,
> > > > partitions, or file paths) firmware is allowed to own and what
> the OS is
> > > and
> > > > is not allowed to do. e.g., the OS is allowed to erase and
> recreate the
> > > OS
> > > > partitions, but it is not allowed to write a blank GPT or
> erase the
> > > system
> > > > partition.
> > > >
> > > > I think the EBBR spec should focus on defining exactly what
> restrictions
> > > on
> > > > the OS are, and how the restrictions are communicated. Then OS
> vendors
> > > have
> > > > a fighting chance of supporting the restricted platforms well.
> > > >
> > > > Ultimately though this is a guide and the OS could choose to
> ignore the
> > > > restrictions... in which case it gets to keep the unbootable
> brick when
> > > it
> > > > does. :-)
> > >
> > > Agree with all above.
> > >
> > > Also I think we can turn at least part of the original issue into a
> > > concrete question.
> > >
> > > We have a SOC with some magic values hard coded into its boot
> ROM. The
> > > System Firmware author wants to ship it with the following GPT
> on the
> > > shared eMMC.
> > >
> > > LBA0 Protective MBR
> > > LBA1 Primary GPT header
> > > LBA2..18001 Reserved, mixture of dead space and a system firmware
> > > loaded by Boot rom
> > > LBA18002 Start of partition arrray (Entry 1, 2, 3, 4)
> > > ...
> > > LBA18033 End of partition arrray
> > > LBA18034 Start of allocatable partition space
> > > LBA-33..-1 End of disk is labelled as normal
> > >
> > > (or in a shorter GPT jargon form, a system where
> PartitionEntryLBA is
> > > 18002).
> > >
> > > Is such a system EBBR compliant? If yes, should it be?
> > >
> > > I would say it is not EBBR compliant because it does not follow
> EFI spec
> > and we mandate it in EBBR.
>
> Sure, if there is language in the EFI spec that prohibits this then the
> answer is a no brainer.
>
> Assuming you've found such language could you quote your references? ;-)
>
> Oups! I thought of GPT Header being at 18002.....
> as you push the firstUsableLBA... it seems to be valid in that EFI
> compliant and hence EBBR compliant ;-)
>
> That said to get the GPT Partition move, the spec patch to table 20 is
> not impressive:
> image.png
> - set to 0x000001 (ie...
> + the LBA to the GPT partition header
The position of the GPT *HEADER* in Daniel's example is LBA 1 and should
not be changed to stay UEFI compliant.
Daniel moved the first GPT *TABLE* whose position is defined in the GPT
header and this is UEFI compliant.
Best regards
Heinrich
>
>
> Daniel.
>
>
> > Is the use case "valid"? I think it is valid because when you deal
> with
> > immutable BootROM you don't want complex code, GPT may evolve so
> that you
> > would have to evolve the BootROM...
> > If we conclude this is a valid use case (and not creating ugly
> legacy to
> > deal with in the future), we need a clean reservation in EFI so
> that GPT
> > can start at an arbitrary LBA as 18002.
> > enhancing the protective MBR semantics does not seem too complex to
> > achieve.
> > Can we list SoCs that have similar characteristic?
> >
> > >
> > > Daniel.
> > >
> > >
> > > PS 18002 is arbitrary but I think the example is sufficient in this
> > > form and it was easier to diagram with a concrete number.
> > >
> >
> >
> > --
> > François-Frédéric Ozog | *Director Linaro Edge & Fog Computing Group*
> > T: +33.67221.6485
> > francois.ozog(a)linaro.org <mailto:francois.ozog@linaro.org> |
> Skype: ffozog
>
>
>
> --
>
> François-Frédéric Ozog | /Director Linaro Edge & Fog Computing Group/
> T: +33.67221.6485
> francois.ozog(a)linaro.org <mailto:francois.ozog@linaro.org> | Skype: ffozog
>
>
Hi,
yet another email to spam you more....
I propose to have an Android DT overlay presentation next call and add
topics that may arise from the list. Should you think we should
discuss a particular topic, please respond to this mail thread.
Cordially,
Francois-Frederic
Hi,
Please find below the May 27th agenda:
- Project overall: FF (5 minutes)
- EBBR spec / DT stuff advances (mail thread): Grant (10 minutes)
- dynamic parts of device trees presentation: Heinrich (30 minutes)
- DTviewer presentation and demo: CVS (15 minutes)
Scratch pad notes and agenda can be found here:
https://docs.google.com/document/d/1GfYYph_XKt1LHuCs1w9kjvyyYYw1R7AH3dlZwIX…
--
FF
PS: I bcc'ed different lists until we have everyone on the
boot-architecture mailing list. Please make sure you are on this list.
The work addressed in DT Evolution project spans many operating
systems, boot firmwares, trust environments and processor
architectures.
UEFI 2.8 Errata A changed RuntimeServiceSupported value to be passed via
an EFI_RT_PROPERTIES_TABLE instead of via a runtime variable.
This is a breaking change and we should do a new EBBR release in short
order to keep EBBR up to date with what is in UEFI. However, real world
impact is minimal. U-Boot has already converted to the new method, and
Linux only ever implemented the EFI_RT_PROPERTIES_TABLE method.
Cc: Andrei Warkentin <awarkentin(a)vmware.com>
Cc: Francois Ozog <francois.ozog(a)linaro.org>
Cc: Ard Biesheuvel <ardb(a)kernel.org>
Signed-off-by: Grant Likely <grant.likely(a)arm.com>
---
source/chapter2-uefi.rst | 7 ++++---
source/references.rst | 6 +++---
2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst
index 82b1a42..c42691b 100644
--- a/source/chapter2-uefi.rst
+++ b/source/chapter2-uefi.rst
@@ -9,7 +9,7 @@ platforms.
UEFI Version
============
-This document uses version 2.8 of the UEFI specification [UEFI]_.
+This document uses version 2.8 Errata A of the UEFI specification [UEFI]_.
UEFI Compliance
===============
@@ -111,7 +111,7 @@ during both boot services and runtime services.
However, it isn't always practical for all EFI_RUNTIME_SERVICES functions
to be callable during runtime services due to hardware limitations.
If any EFI_RUNTIME_SERVICES functions are only available during boot services
-then firmware shall provide the global `RuntimeServicesSupported` variable to
+then firmware shall provide the `EFI_RT_PROPERTIES_TABLE` to
indicate which functions are available during runtime services.
Functions that are not available during runtime services shall return
EFI_UNSUPPORTED.
@@ -202,7 +202,8 @@ If a platform does not implement modifying non-volatile variables with
SetVariable() after ExitBootServices(),
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]_ § 8.1.
+via the `RuntimeServicesSupported` value in the `EFI_RT_PROPERTIES_TABLE`
+as defined in [UEFI]_ § 4.6.
EFI applications can read `RuntimeServicesSupported` to determine if calls
to SetVariable() need to be performed before calling ExitBootServices().
diff --git a/source/references.rst b/source/references.rst
index d901bb1..1eb0509 100644
--- a/source/references.rst
+++ b/source/references.rst
@@ -20,6 +20,6 @@
<https://static.docs.arm.com/den0044/b/DEN0044B_Server_Base_Boot_Requirement…>`_
8 March 2016, `Arm Limited <http://arm.com>`_
-.. [UEFI] `Unified Extensable Firmware Interface Specification v2.8
- <http://www.uefi.org/sites/default/files/resources/UEFI_Spec_2_8_final.pdf>`_,
- March 2019, `UEFI Forum <http://www.uefi.org>`_
+.. [UEFI] `Unified Extensable Firmware Interface Specification v2.8 Errata A
+ <https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_A_Feb14.pdf>`_,
+ February 2020, `UEFI Forum <http://www.uefi.org>`_
--
2.20.1
Hi all,
I'm considering doing a quick point-release for EBBR to address the
change to RuntimeServicesSupported in UEFI 2.8 Errata A. From 2.8final
to 2.8_A, RuntimeServicesSupported changed from being a variable to data
in a system table entry. U-Boot and Linux have been updated to the UEFI
method. EBBR needs to be changed to match.
There are patches on this list under discussion now. Once that is
complete and the patches merged, how does everyone feel about an EBBR
v1.0.1 release before the end of May?
At this moment, the v1.0.1 changes would include:
e47952b (HEAD -> master, glikely/master) Specify details of how a DTB is
passed to the OS
c155e96 Update spec to address UEFI 2.8 Errata A
7fad894 (origin/master, origin/HEAD) Fix all UEFI references to be the
same version
498cad2 trivial: Fix typo in chater 3 title
2c40029 Merge pull request #43 from orangecms/link-to-linux-doc
1e51a1e Update link to Linux docs which changed to rst
be7ddfa Update CONTRIBUTING.rst
763aed0 Update CONTRIBUTING.rst
All of the above can be found queued up at http://github.com/glikely/ebbr
g.
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