diff options
authorSameer Goel <sgoel@codeaurora.org>2017-02-07 14:19:20 -0700
committerAKASHI Takahiro <takahiro.akashi@linaro.org>2017-04-03 09:43:06 +0900
commit9cb987c300d258a0b9a1795d66c9626af4ad2e7e (patch)
parenta7a7d1ec1ffbf7267d0aae0e031e927e8f274a61 (diff)
efi/libstub/arm*: Set default address and size cells values for an empty dtbarm64/kdump
In cases where a device tree is not provided (ie ACPI based system), an empty fdt is generated by efistub. #address-cells and #size-cells are not set in the empty fdt, so they default to 1 (4 byte wide). This can be an issue on 64-bit systems where values representing addresses, etc may be 8 bytes wide as the default value does not align with the general requirements for an empty DTB, and is fragile when passed to other agents as extra care is required to read the entire width of a value. This issue is observed on Qualcomm Technologies QDF24XX platforms when kexec-tools inserts 64-bit addresses into the "linux,elfcorehdr" and "linux,usable-memory-range" properties of the fdt. When the values are later consumed, they are truncated to 32-bit. Setting #address-cells and #size-cells to 2 at creation of the empty fdt resolves the observed issue, and makes the fdt less fragile. Signed-off-by: Sameer Goel <sgoel@codeaurora.org> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
1 files changed, 26 insertions, 2 deletions
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index 260c4b4..82973b8 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -16,6 +16,22 @@
#include "efistub.h"
+static void fdt_update_cell_size(efi_system_table_t *sys_table, void *fdt)
+ int offset;
+ offset = fdt_path_offset(fdt, "/");
+ /* Set the #address-cells and #size-cells values for an empty tree */
+ fdt_setprop_u32(fdt, offset, "#address-cells",
+ fdt_setprop_u32(fdt, offset, "#size-cells", EFI_DT_SIZE_CELLS_DEFAULT);
static efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
unsigned long orig_fdt_size,
void *fdt, int new_fdt_size, char *cmdline_ptr,
@@ -42,10 +58,18 @@ static efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
- if (orig_fdt)
+ if (orig_fdt) {
status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
- else
+ } else {
status = fdt_create_empty_tree(fdt, new_fdt_size);
+ if (status == 0) {
+ /*
+ * Any failure from the following function is non
+ * critical
+ */
+ fdt_update_cell_size(sys_table, fdt);
+ }
+ }
if (status != 0)
goto fdt_set_fail;