Revert "fdt: Make sure there is no stale initrd left"

This reverts commit 9fe2e4b464.

Commit 9fe2e4b464 ("fdt: Make sure there is no stale initrd left")
introduces a regression in case when U-Boot transfers control to an EFI
app which acts as a subsequent bootloading program. Such an app might
try to set "linux,initrd-start" and "linux,initrd-end" fdt properties,
but by that time those properties are already removed by the code added
in the mentioned commit.

Particularly, the issue was observed on the E850-96 board where GBL EFI
app [1] can't run Android successfully anymore. More specifically, the
kernel can't see the ramdisk and panics with next messages:

    /dev/root: Can't open blockdev
    VFS: Cannot open root device "" or unknown-block(0,0): error -6
    Please append a correct "root=" boot option; ...
    Kernel panic - not syncing: VFS: Unable to mount root fs on
    unknown-block(0,0)

fdt_initrd() function (where initrd dts properties are removed) is
called two times:

1. First it's called by EFI boot manager (e.g. as a part of U-Boot
Standard Boot mechanism) when it's installing FDT:

    fdt_initrd
    image_setup_libfdt
    efi_install_fdt
    efi_bootmgr_run
    efi_mgr_boot

It's already enough for EFI app to malfunction. But then it's also
called second time:

2. From the EFI app, via EFI DT fixup protocol:

    fdt_initrd
    image_setup_libfdt
    efi_dt_fixup
    struct efi_dt_fixup_protocol efi_dt_fixup_prot = {
        .fixup = efi_dt_fixup
    };

See [2] for specific GBL code which sets those fdt properties and then
runs DT fixup protocol callback.

This issue was discussed [3], but no action was taken since then. Revert
this patch for now, until a proper solution can be found.

[1] https://source.android.com/docs/core/architecture/bootloader/generic-bootloader/gbl-dev
[2] https://android.googlesource.com/platform/bootable/libbootloader/+/refs/heads/gbl-mainline/gbl/libgbl/src/android_boot/mod.rs#208
[3] https://lists.denx.de/pipermail/u-boot/2025-July/593879.html

Fixes: 9fe2e4b464 ("fdt: Make sure there is no stale initrd left")
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
This commit is contained in:
Sam Protsenko
2025-09-29 17:19:26 -05:00
committed by Tom Rini
parent 5a3c306aaf
commit 072264c4b3

View File

@@ -224,24 +224,15 @@ int fdt_initrd(void *fdt, ulong initrd_start, ulong initrd_end)
int is_u64;
uint64_t addr, size;
/* just return if the size of initrd is zero */
if (initrd_start == initrd_end)
return 0;
/* find or create "/chosen" node. */
nodeoffset = fdt_find_or_add_subnode(fdt, 0, "chosen");
if (nodeoffset < 0)
return nodeoffset;
/*
* Although we didn't setup an initrd, there could be a stale
* initrd setting from the previous boot firmware in the live
* device tree. So, make sure there is no setting left if we
* don't want an initrd.
*/
if (initrd_start == initrd_end) {
fdt_delprop(fdt, nodeoffset, "linux,initrd-start");
fdt_delprop(fdt, nodeoffset, "linux,initrd-end");
return 0;
}
total = fdt_num_mem_rsv(fdt);
/*