> Date: Thu, 11 Aug 2022 20:48:58 +0300 > From: Sergii Dmytruk <sergii.dmyt...@3mdeb.com>
Hi Sergeii, Sorry for the late reply. I was enjoying a vacation without a laptop nearby ;). Having fwupd support for OpenBSD would be great! I have done some work on adding support for EFI runtime services on OpenBSD/amd64, based on the code for OpenBSD/arm64. My plan was to implement an ioctl(2) interface that is compatible with FreeBSD's <sys/efiio.h> interface. Theo objected to putting EFI-related headers in /usr/include/sys, so the EFI-related headers will probably end up in /usr/include/dev/efi (so you'd be include <dev/efi/efiio.h> instead). I hope to have some time to make progress on this next week, so let me come back to you then. Cheers, Mark > Hello OpenBSD devs, > > Background > ---------- > > As some might know, FreeBSD gained an interface for querying ESRT > about a year ago ([1], [2]), which was done as part of [3]. > > [1]: https://reviews.freebsd.org/rGd12d651f8692cfcaf6fd0a6e8264c29547f644c9 > [2]: https://reviews.freebsd.org/rG24f398e7a153a05a7e94ae8dd623e2b6d28d94eb > [3]: https://nlnet.nl/project/fwdup-BSD/ > > Adding it allowed to make UEFI capsule plugin of fwupd [4] work for > FreeBSD [5] to perform firmware updates on EFI systems. > > [4]: https://fwupd.org/ > [5]: > https://github.com/fwupd/fwupd/blob/main/plugins/uefi-capsule/fu-uefi-backend-freebsd.c > > Now it's turn for OpenBSD and we would like to ask about requirements > and recommendations on the API and its implementation such that they > would be accepted by the upstream. > > ESRT Part > --------- > > Initial idea is to use sysctl() interface like so: > > ``` > void *esrt; > size_t esrt_len; > int mib[] = { CTL_HW, HW_ESRT }; > > esrt_len = 0; > if (sysctl(mib, 2, NULL, &esrt_len, NULL, 0) == -1 && errno != ENOMEM) > err(1, "sysctl"); > > esrt = malloc(esrt_len); > if (esrt == NULL) > err(1, "malloc"); > > if (sysctl(mib, 2, esrt, &esrt_len, NULL, 0) == -1) > err(1, "sysctl"); > ``` > > However, FreeBSD decided in favour of ioctl() on /dev/efi. > > EFI variables Part > ------------------ > > I don't see an implementation of `efivar` or `efiboot` or anything > similar, so it needs to be added and provide at least this API subset > to be usable with fwupd: > > * efi_append_variable() > appends data of size to the variable specified by guid and name > * efi_del_variable() > deletes the variable specified by guid and name > * efi_get_variable() > gets variable's data_size, and its attributes are stored in > attributes > * efi_get_variable_attributes() > gets attributes for the variable specified by guid and name > * efi_get_variable_size() > gets the size of the data for the variable specified by guid and name > * efi_get_next_variable_name() > iterates across the currently extant variables, passing back a guid > and name > * efi_guid_to_name() > translates from an efi_guid_t to a well known name > * efi_guid_to_symbol() > translates from an efi_guid_t to a unique (within libefivar) C-style > symbol name > * efi_guid_to_str() > allocates a suitable string and populates it with string > representation of a UEFI GUID > * efi_name_to_guid() > translates from a well known name to an efi_guid_t > * efi_set_variable() > sets the variable specified by guid and name > * efi_str_to_guid() > parses a UEFI GUID from string form to an efi_guid_t > * efi_variables_supported() > checks if EFI variables are accessible > * efi_generate_file_device_path() > generates an EFI file device path for an EFI binary from a filesystem > path > > Probably should be implemented as a minimal port of efivar [6] with > sufficient functionality rather than a separate project. Either way, > this too needs new kernel API for accessing EFI variables. Will sysctl() > do or a new pseudo-device or something else is needed? Usage of > existing implementations can be seen in FreeBSD [7] and Linux [8] (Linux > uses sysfs for this). > > [6]: https://github.com/rhboot/efivar > [7]: > https://github.com/freebsd/freebsd-src/blob/release/12.2.0/lib/libefivar/efivar.c > [8]: https://github.com/rhboot/efivar/blob/main/src/efivarfs.c > > Implementation > -------------- > > I started making an EFI driver for amd64 in [9] (WIP). There isn't much > to see there yet, but let me know if you have any specific ideas about > implementation of ESRT and EFI variables, they can help to avoid too > many rounds of review. For now I'm looking at `efifb.c` and > `arm64/dev/efi.c` for how to do things. > > By the way, I couldn't find OpenBSD kernel hacking guide, manual or > README. Is there a resource like that? Something that could answer > questions like: > > * should new EFI-declarations go to `sys/dev/acpi/efi.h`? > * should efiboot look for ESRT table like it does with 2 other tables? > > [9] https://github.com/openbsd/src/compare/master...3mdeb:openbsd-src:esrt > > Expectations > ------------ > > Please help shaping this API, so you'll be happy with it :) > > Best regards, > Sergii > >
