[PATCH] efi/libstub/arm*: Set default address and size cells values for an empty dtb

Jeffrey Hugo
2017-02-07T17:59:50Z

From: Sameer Goel <sgoel-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>

In cases where a device tree is not provided (ie ACPI based system), an
empty fdt is generated by efistub. Sets the address and size cell values
in a generated fdt to support 64 bit addressing.

This enables kexec/kdump on Qualcomm Technologies QDF24XX platforms as those
utilities will read the address/size values from the fdt, and such values
may exceed the range provided by the 32 bit default.

Change-Id: Ie7f3637e375bd6631c6bda1f7b3c9003765ff4a5
Signed-off-by: Sameer Goel <sgoel-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
Signed-off-by: Jeffrey Hugo <jhugo-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
---
drivers/firmware/efi/libstub/fdt.c | 38 +++++++++++++++++++++++++++++++++++++-
1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index 921dfa0..def5c9c 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -16,6 +16,34 @@

#include "efistub.h"

+#define EFI_DT_ADDR_CELLS_DEFAULT 2
+#define EFI_DT_SIZE_CELLS_DEFAULT 2
+
+static void fdt_update_cell_size(efi_system_table_t *sys_table, void *fdt)
+{
+ int offset;
+ int status;
+
+ offset = fdt_path_offset(fdt, "/");
+ /* Set the #address-cells and #size-cells values for an empty tree */
+
+ status = fdt_setprop_u32(fdt, offset, "#address-cells",
+ EFI_DT_ADDR_CELLS_DEFAULT);
+ if (status) {
+ pr_efi(sys_table,
+ "Failed to set #address-cells for empty dtb\n");
+ return;
+ }
+
+ status = fdt_setprop_u32(fdt, offset, "#size-cells",
+ EFI_DT_SIZE_CELLS_DEFAULT);
+ if (status) {
+ pr_efi(sys_table,
+ "Failed to set #size-cells for empty dtb\n");
+ return;
+ }
+}
+
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,
@@ -44,8 +72,16 @@ static efi_status_t update_fdt(efi_system_table_t *sys_table, void *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;
--
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