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authorSameer Goel <sgoel@codeaurora.org>2017-04-03 11:26:33 +0900
committerCatalin Marinas <catalin.marinas@arm.com>2017-04-05 18:32:47 +0100
commitae8a442dfdc4fc3197c8aa09bb179345b2c1f49e (patch)
tree162a2253bc2024f4bdf28ca1e1b359ba400bdd48 /drivers/firmware
parentfcbd4bb71e913d4be7a6d39f622479499bb73bfe (diff)
downloadlinux-next-ae8a442dfdc4fc3197c8aa09bb179345b2c1f49e.tar.gz
efi/libstub/arm*: Set default address and size cells values for an empty dtb
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> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'drivers/firmware')
-rw-r--r--drivers/firmware/efi/libstub/fdt.c28
1 files changed, 26 insertions, 2 deletions
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index 260c4b4b492e..82973b86efe4 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -16,6 +16,22 @@
#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;
+
+ offset = fdt_path_offset(fdt, "/");
+ /* Set the #address-cells and #size-cells values for an empty tree */
+
+ fdt_setprop_u32(fdt, offset, "#address-cells",
+ EFI_DT_ADDR_CELLS_DEFAULT);
+
+ 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;