| Message ID | 20170328065319.16154-1-takahiro.akashi@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 28 March 2017 at 07:53, AKASHI Takahiro <takahiro.akashi@linaro.org> wrote: > From: Sameer Goel <sgoel@codeaurora.org> > > 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> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > drivers/firmware/efi/libstub/fdt.c | 28 ++++++++++++++++++++++++++-- > 1 file 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; > -- > 2.11.1 >
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;