Re: [PATCH v3] tpm, tpm_crb: fix unaligned read of the command buffer address

From: Jason Gunthorpe
Date: Tue Sep 15 2015 - 13:22:35 EST


On Tue, Sep 15, 2015 at 08:05:40PM +0300, Jarkko Sakkinen wrote:
> The command buffer address must be read with exactly two 32-bit reads.
> Otherwise, on some HW platforms, it seems that HW will abort the read
> operation, which causes CPU to fill the read bytes with 1's. Therefore,
> we cannot rely on memcpy_fromio() but must call ioread32() two times
> instead.
>
> Also, this matches the PC Client Platform TPM Profile specification,
> which defines command buffer address with two 32-bit fields.
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> drivers/char/tpm/tpm_crb.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index b4564b6..c09b370 100644
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -68,7 +68,8 @@ struct crb_control_area {
> u32 int_enable;
> u32 int_sts;
> u32 cmd_size;
> - u64 cmd_pa;
> + u32 cmd_pa_low;
> + u32 cmd_pa_high;
> u32 rsp_size;
> u64 rsp_pa;

What about rsp_pa?

> } __packed;

As I mentioned, drop the __packed.

Otherwise:

Reviewed-By: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>

Jason
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