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>
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