On Sun, 27 Oct 2024 at 20:30, Simon Glass sjg@chromium.org wrote:
Hi Sughosh,
On Fri, 25 Oct 2024 at 13:15, Sughosh Ganu sughosh.ganu@linaro.org wrote:
From: Masahisa Kojima kojima.masahisa@socionext.com
One of the problems OS installers face, when running in EFI, is that the mounted ISO after calling ExitBootServices goes away. For some distros this is a problem since they rely on finding some core packages before continuing the installation. Distros have works around this -- e.g Fedora has a special kernel command line parameter called inst.stage2 [0].
ACPI has NFIT and NVDIMM support to provide ramdisks to the OS, but we don't have anything in place for DTs. Linux and device trees have support for persistent memory devices. So add a function that can inject a pmem node in a DT, so we can use it when launhing OS installers with EFI.
[0] https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/7/html/ins...
Signed-off-by: Masahisa Kojima kojima.masahisa@socionext.com Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org
boot/fdt_support.c | 41 +++++++++++++++++++++++++++++++++++++++-- include/fdt_support.h | 13 +++++++++++++ 2 files changed, 52 insertions(+), 2 deletions(-)
Can you please use the ofnode interface for this? We are trying not to add more of this kind of fixup, as it means someone will have to port it over later.
See EVT_FT_FIXUP
Are you suggesting using the EVT_FT_FIXUP interface for adding the pmem node? If so, how does this work on platforms which enable livetree? Looking at the code, I see that the EVT_FT_FIXUP gets called only when the livetree is not active. However, I am not able to find any place where the livetree is getting disabled. We do have a function, oftree_to_fdt() which flattens a livetree, but I don't see it getting called from anywhere except from a 'upl' command. The of_root pointer does get set in initr_of_live(), but apart from dm_test_pre_run(), I do not see where we disable the livetree and set of_root to NULL.
So on platforms which do enable livetree, how does this fixup work? What am I missing?
-sughosh
Regards, Simon