Messages in this thread | | | Subject | Re: [PATCH v4 8/8] bus: mhi: core: Ensure non-zero session or sequence ID values are used | From | Jeffrey Hugo <> | Date | Mon, 4 May 2020 08:33:34 -0600 |
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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.
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