From 0bcaa9040d058684d58c36ef273b8946996c7078 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Thu, 23 Oct 2014 16:33:33 +0100 Subject: [PATCH] efi: efi-stub: notify on DTB absence 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 Acked-by: Leif Lindholm Acked-by: Ard Biesheuvel Acked-by: Roy Franz Acked-by: Matt Fleming Signed-off-by: Ard Biesheuvel --- 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 75ee059..eb48a1a 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, -- 2.7.4