From: Tyrel Datwyler

Sent: 27 January 2017 18:03
On 01/26/2017 05:50 PM, Benjamin Herrenschmidt wrote:

quoted

On Thu, 2017-01-26 at 17:42 -0800, Tyrel Datwyler wrote:

quoted

On 01/26/2017 12:22 PM, Michal Suchnek wrote:

quoted

Hello,

building ibmvtpm I noticed gcc warning complaining that second word
of
struct ibmvtpm_crq in tpm_ibmvtpm_suspend is uninitialized.

The structure is defined as

struct ibmvtpm_crq {
        u8 valid;
        u8 msg;
        __be16 len;
        __be32 data;
        __be64 reserved;
} __attribute__((packed, aligned(8)));

initialized as

        struct ibmvtpm_crq crq;
        u64 *buf = (u64 *) &crq;
...
        crq.valid = (u8)IBMVTPM_VALID_CMD;
        crq.msg = (u8)VTPM_PREPARE_TO_SUSPEND;

and submitted with

        rc = ibmvtpm_send_crq(ibmvtpm->vdev, cpu_to_be64(buf[0]),
                              cpu_to_be64(buf[1]));

Isn't the real fubar here the use of that memory layout structure at all?
It would probably all be better if the call looked like:
	rc = ibmvtpm_send_crq(ibmvtpm->vdev, MAKE_REQ(IBMVTPM_VALID_CMD,
		VTPM_PREPARE_TO_SUSPEND, xxx_len, xxx_data), 0);
and MAKE_REQ() did all the required endian independant shifts to generate
the correct 32bit value.

	David