On 4 March 2015 at 19:06, Roy Franz <roy.franz@xxxxxxxxxx> wrote:
> On Wed, Mar 4, 2015 at 4:02 AM, Ard Biesheuvel
> <ard.biesheuvel@xxxxxxxxxx> wrote:
>> When allocating memory for the copy of the FDT that the stub
>> modifies and passes to the kernel, it uses the current size as
>> an estimate of how much memory to allocate, and increases it page
>> by page if it turns out to be too small. However, when loading
>> the FDT from a UEFI configuration table, the estimated size is
>> left at its default value of zero, and the allocation loop runs
>> starting from zero all the way up to the allocation size that
>> finally fits the updated FDT.
>>
>> Instead, retrieve the size of the FDT from the FDT header when
>> loading it from the UEFI config table.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>> ---
>> drivers/firmware/efi/libstub/arm-stub.c | 7 +++----
>> drivers/firmware/efi/libstub/efistub.h | 2 +-
>> drivers/firmware/efi/libstub/fdt.c | 7 ++++++-
>> 3 files changed, 10 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
>> index dcae482a9a17..e29560e6b40b 100644
>> --- a/drivers/firmware/efi/libstub/arm-stub.c
>> +++ b/drivers/firmware/efi/libstub/arm-stub.c
>> @@ -175,7 +175,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
>> unsigned long initrd_addr;
>> u64 initrd_size = 0;
>> unsigned long fdt_addr = 0; /* Original DTB */
>> - u64 fdt_size = 0; /* We don't get size from configuration table */
>> + unsigned long fdt_size = 0;
>> char *cmdline_ptr = NULL;
>> int cmdline_size = 0;
>> unsigned long new_fdt_addr;
>> @@ -239,8 +239,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
>> } else {
>> status = handle_cmdline_files(sys_table, image, cmdline_ptr,
>> "dtb=",
>> - ~0UL, (unsigned long *)&fdt_addr,
>> - (unsigned long *)&fdt_size);
>> + ~0UL, &fdt_addr, &fdt_size);
>>
>> if (status != EFI_SUCCESS) {
>> pr_efi_err(sys_table, "Failed to load device tree!\n");
>> @@ -252,7 +251,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
>> 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);
>> + fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
>> if (fdt_addr)
>> pr_efi(sys_table, "Using DTB from configuration table\n");
>> }
>> diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
>> index 47437b16b186..e334a01cf92f 100644
>> --- a/drivers/firmware/efi/libstub/efistub.h
>> +++ b/drivers/firmware/efi/libstub/efistub.h
>> @@ -41,7 +41,7 @@ efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
>> unsigned long fdt_addr,
>> unsigned long fdt_size);
>>
>> -void *get_fdt(efi_system_table_t *sys_table);
>> +void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size);
>>
>> void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
>> unsigned long desc_size, efi_memory_desc_t *runtime_map,
>> diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
>> index 91da56c4fd54..ef5d764e2a27 100644
>> --- a/drivers/firmware/efi/libstub/fdt.c
>> +++ b/drivers/firmware/efi/libstub/fdt.c
>> @@ -323,7 +323,7 @@ fail:
>> return EFI_LOAD_ERROR;
>> }
>>
>> -void *get_fdt(efi_system_table_t *sys_table)
>> +void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
>> {
>> efi_guid_t fdt_guid = DEVICE_TREE_GUID;
>> efi_config_table_t *tables;
>> @@ -336,6 +336,11 @@ void *get_fdt(efi_system_table_t *sys_table)
>> for (i = 0; i < sys_table->nr_tables; i++)
>> if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
>> fdt = (void *) tables[i].table;
>> + if (fdt_check_header(fdt) != 0) {
>> + pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
>> + return NULL;
>> + }
>> + *fdt_size = fdt_totalsize(fdt);
>> break;
>> }
>>
>> --
>> 1.8.3.2
>>
>
> Looks good.
>
> Reviewed-by: Roy Franz <roy.franz@xxxxxxxxxx>
Thanks Roy.
@Matt: would you mind taking this one?
Thanks,
Ard.
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