On 3/20/24 12:14, Rob Herring wrote:
On Mon, Mar 18, 2024 at 4:31 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
On 3/18/24 12:26, Rob Herring wrote:
+Stephen
On Mon, Mar 18, 2024 at 12:09 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
Hi,
On Fri, Mar 17, 2023 at 12:34:14AM -0500, Frank Rowand wrote:
When enabling CONFIG_OF on a platform where of_root is not populated by
firmware, we end up without a root node. In order to apply overlays and
create subnodes of the root node, we need one. Create this root node
by unflattening an empty builtin dtb.
If firmware provides a flattened device tree (FDT) then the FDT is
unflattened via setup_arch(). Otherwise setup_of(), which is called
immediately after setup_arch(), will create the default root node
if it does not exist.
Signed-off-by: Frank Rowand <frowand.list@xxxxxxxxx>
This patch results in a crash on nios2.
This patch was never applied. I assume you meant a later version of it
that did get applied.
Building nios2:10m50-ghrd:10m50_defconfig:10m50_devboard.dts ... running ...R failed (crashed)
Booting with DT?
------------
qemu log:
earlycon: uart8250 at MMIO32 0x18001600 (options '')
printk: legacy bootconsole [uart8250] enabled
Linux version 6.8.0-11409-gf6cef5f8c37f (groeck@desktop) (nios2-linux-gcc (GCC) 11.4.0, GNU ld (GNU Binutils) 2.40) #1 Sun Mar 17 23:38:59 PDT 2024
Kernel panic - not syncing: early_init_dt_alloc_memory_arch: Failed to allocate 72 bytes align=0x40
---[ end Kernel panic - not syncing: early_init_dt_alloc_memory_arch: Failed to allocate 72 bytes align=0x40 ]---
nios2 looks utterly broken to me. This change should be a nop unless
initial_boot_params is NULL. It looks like it is possible for r6 (dtb
address) to be 0 depending on kconfig options, but that would have
skipped copying and unflattening which would then panic in
setup_cpuinfo(). If initial_boot_params is not NULL, then the same
early_init_dt_alloc_memory_arch() calls should fail when copying the
DT. So I don't see how nios2 booting with DT ever worked.
For nios2, in early_init_devtree():
void __init early_init_devtree(void *params)
{
__be32 *dtb = (u32 *)__dtb_start;
...
if (be32_to_cpu((__be32) *dtb) == OF_DT_HEADER)
params = (void *)__dtb_start;
That worked fine until this patch. Starting with this patch, __dtb_start
always points to a valid empty devicetree blob, which overrides the
devicetree blob passed to early_init_devtree(). This causes the problem.
With an external DTB, it doesn't boot with or without this patch. It
just dies in different spots. Before it just skipped any memory
No, that is incorrect. Up to this patch it booted just fine with an
external dtb using the "-initrd" command line argument, and I explained
to you above why this is the case.
I guess you are saying I should stop boot testing nios2. I'll do just that.
Saves me resources and avoids discussions like this.
Guenter
