From: Jeffrey Hugo <jhugo@codeaurora.org>
To: Bhaumik Bhatt <bbhatt@codeaurora.org>, mani@kernel.org
Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
hemantk@codeaurora.org
Subject: Re: [PATCH v4 8/8] bus: mhi: core: Ensure non-zero session or sequence ID values are used
Date: Mon, 4 May 2020 08:33:34 -0600 [thread overview]
Message-ID: <2a249d99-b1e7-7943-0ed4-d5529f7abc33@codeaurora.org> (raw)
In-Reply-To: <1588386725-1165-9-git-send-email-bbhatt@codeaurora.org>
On 5/1/2020 8:32 PM, Bhaumik Bhatt wrote:
> While writing any sequence or session identifiers, it is possible that
> the host could write a zero value, whereas only non-zero values should
> be supported writes to those registers. Ensure that the host does not
> write a non-zero value for them and also log them in debug messages.
>
> Suggested-by: Jeffrey Hugo <jhugo@codeaurora.org>
> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
> ---
> drivers/bus/mhi/core/boot.c | 15 +++++++--------
> drivers/bus/mhi/core/internal.h | 1 +
> 2 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/bus/mhi/core/boot.c b/drivers/bus/mhi/core/boot.c
> index e5fcde1..9fe9c59 100644
> --- a/drivers/bus/mhi/core/boot.c
> +++ b/drivers/bus/mhi/core/boot.c
> @@ -43,10 +43,7 @@ void mhi_rddm_prepare(struct mhi_controller *mhi_cntrl,
> lower_32_bits(mhi_buf->dma_addr));
>
> mhi_write_reg(mhi_cntrl, base, BHIE_RXVECSIZE_OFFS, mhi_buf->len);
> - sequence_id = prandom_u32() & BHIE_RXVECSTATUS_SEQNUM_BMSK;
> -
> - if (unlikely(!sequence_id))
> - sequence_id = 1;
> + sequence_id = (MHI_RANDOM_U32_NONZERO & BHIE_RXVECSTATUS_SEQNUM_BMSK);
I don't think this math works. For example, if MHI_RANDOM_U32_NONZERO
is 0x0FF0, and BHIE_RXVECSTATUS_SEQNUM_BMSK is 0xF, then sequence_id
will end up being 0.
--
Jeffrey Hugo
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
next prev parent reply other threads:[~2020-05-04 14:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-02 2:31 [PATCH v4 0/8] Bug fixes and improved logging in MHI Bhaumik Bhatt
2020-05-02 2:31 ` [PATCH v4 1/8] bus: mhi: core: Refactor mhi queue APIs Bhaumik Bhatt
2020-05-02 2:31 ` [PATCH v4 2/8] bus: mhi: core: Cache intmod from mhi event to mhi channel Bhaumik Bhatt
2020-05-02 2:32 ` [PATCH v4 3/8] bus: mhi: core: Add range check for channel id received in event ring Bhaumik Bhatt
2020-05-02 2:32 ` [PATCH v4 4/8] bus: mhi: core: Read transfer length from an event properly Bhaumik Bhatt
2020-05-04 14:31 ` Jeffrey Hugo
2020-05-02 2:32 ` [PATCH v4 5/8] bus: mhi: core: Handle firmware load using state worker Bhaumik Bhatt
2020-05-02 2:32 ` [PATCH v4 6/8] bus: mhi: core: Return appropriate error codes for AMSS load failure Bhaumik Bhatt
2020-05-02 2:32 ` [PATCH v4 7/8] bus: mhi: core: Improve debug logs for loading firmware Bhaumik Bhatt
2020-05-02 2:32 ` [PATCH v4 8/8] bus: mhi: core: Ensure non-zero session or sequence ID values are used Bhaumik Bhatt
2020-05-04 14:33 ` Jeffrey Hugo [this message]
2020-05-05 2:32 ` bbhatt
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