From: Mark Rutland <mark.rutland@xxxxxxx>
In the absence of a DTB configuration table, the EFI stub will happily
continue attempting to boot a kernel, despite the fact that this kernel
may not function without a description of the hardware. In this case, as
with a typo'd "dtb=" option (e.g. "dbt=") or many other possible
failures, the only output seen by the user will be the rather terse
output from the EFI stub:
EFI stub: Booting Linux Kernel...
To aid those attempting to debug such failures, this patch adds a notice
when no DTB is found, making the output more helpful:
EFI stub: Booting Linux Kernel...
EFI stub: Generating empty DTB
Additionally, a positive acknowledgement is added when a user-specified
DTB is in use:
EFI stub: Booting Linux Kernel...
EFI stub: Using DTB from command line
Similarly, a positive acknowledgement is added when a DTB from a
configuration table is in use:
EFI stub: Booting Linux Kernel...
EFI stub: Using DTB from configuration table
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Acked-by: Leif Lindholm <leif.lindholm@xxxxxxxxxx>
Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Mark Salter <msalter@xxxxxxxxxx>
Cc: Matt Fleming <matt.fleming@xxxxxxxxx>
Acked-by: Roy Franz <roy.franz@xxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
drivers/firmware/efi/libstub/arm-stub.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
index 75ee05964cbc..eb48a1a1a576 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -247,9 +247,18 @@ unsigned long __init efi_entry(void *handle, efi_system_table_t *sys_table,
goto fail_free_cmdline;
}
}
- if (!fdt_addr)
+
+ if (fdt_addr) {
+ pr_efi(sys_table, "Using DTB from command line\n");
+ } else {
/* Look for a device tree configuration table entry. */
fdt_addr = (uintptr_t)get_fdt(sys_table);
+ if (fdt_addr)
+ pr_efi(sys_table, "Using DTB from configuration table\n");
+ }
+
+ if (!fdt_addr)
+ pr_efi(sys_table, "Generating empty DTB\n");
status = handle_cmdline_files(sys_table, image, cmdline_ptr,
"initrd=", dram_base + SZ_512M,
--
1.8.3.2
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