On 21 June 2018 at 09:42, Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> Commit 79832f0b5f71 ("efi/libstub/tpm: Initialize pointer variables to zero
> for mixed mode") fixes a problem with the tpm code on mixed mode (64 bit
> kernel on 32 bit UEFI), where 64-bit pointer variables are not fully
> initialized by the 32-bit EFI code.
>
> A simlar problem applies to the efi_physical_addr_t variables which
> are written by the get_event_log EFI call. Even though efi_physical_addr_t
> is 64 bit everywhere it seems that some 32 bit UEFI implementations only
> fill in the lower 32 bits when passed a pointer to an efi_physical_addr_t
> to fill.
>
> This commit initializes these to 0 to, to ensure the upper 32 bits are
> 0 in mixed mode. This fixes recent kernels sometimes hanging during
> early boot on mixed mode UEFI systems.
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> Changes in v2:
> -Change commit message to reflect that efi_physical_addr_t is 64 bit
> everywhere and some firmwares only filling the lower 32 bits is somewhat
> unexpected
Thanks Hans
Queued in efi/next
> ---
> drivers/firmware/efi/libstub/tpm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c
> index caa37a6dd9d4..a90b0b8fc69a 100644
> --- a/drivers/firmware/efi/libstub/tpm.c
> +++ b/drivers/firmware/efi/libstub/tpm.c
> @@ -64,7 +64,7 @@ static void efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg)
> efi_guid_t tcg2_guid = EFI_TCG2_PROTOCOL_GUID;
> efi_guid_t linux_eventlog_guid = LINUX_EFI_TPM_EVENT_LOG_GUID;
> efi_status_t status;
> - efi_physical_addr_t log_location, log_last_entry;
> + efi_physical_addr_t log_location = 0, log_last_entry = 0;
> struct linux_efi_tpm_eventlog *log_tbl = NULL;
> unsigned long first_entry_addr, last_entry_addr;
> size_t log_size, last_entry_size;
> --
> 2.17.1
>
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