| Message ID | 1588386725-1165-9-git-send-email-bbhatt@codeaurora.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Bug fixes and improved logging in MHI | expand |
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.
On 2020-05-04 07:33, Jeffrey Hugo wrote: > 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. In this case, SEQNUM BMSK is set to 0x3FFFFFFF so this change will still work as we only supplied a non-zero number macro to AND with the mask. However, I agree that may not be the case always that we would know the bitmask in advance so it is better to fix it for good. Thanks for the catch! I have updated the change to have the macro take the bitmask as a parameter and output a non-zero value.
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); mhi_write_reg_field(mhi_cntrl, base, BHIE_RXVECDB_OFFS, BHIE_RXVECDB_SEQNUM_BMSK, BHIE_RXVECDB_SEQNUM_SHFT, @@ -189,7 +186,9 @@ static int mhi_fw_load_amss(struct mhi_controller *mhi_cntrl, return -EIO; } - dev_dbg(dev, "Starting AMSS download via BHIe\n"); + sequence_id = (MHI_RANDOM_U32_NONZERO & BHIE_TXVECSTATUS_SEQNUM_BMSK); + dev_dbg(dev, "Starting AMSS download via BHIe. Sequence ID:%u\n", + sequence_id); mhi_write_reg(mhi_cntrl, base, BHIE_TXVECADDR_HIGH_OFFS, upper_32_bits(mhi_buf->dma_addr)); @@ -198,7 +197,6 @@ static int mhi_fw_load_amss(struct mhi_controller *mhi_cntrl, mhi_write_reg(mhi_cntrl, base, BHIE_TXVECSIZE_OFFS, mhi_buf->len); - sequence_id = prandom_u32() & BHIE_TXVECSTATUS_SEQNUM_BMSK; mhi_write_reg_field(mhi_cntrl, base, BHIE_TXVECDB_OFFS, BHIE_TXVECDB_SEQNUM_BMSK, BHIE_TXVECDB_SEQNUM_SHFT, sequence_id); @@ -246,14 +244,15 @@ static int mhi_fw_load_sbl(struct mhi_controller *mhi_cntrl, goto invalid_pm_state; } - dev_dbg(dev, "Starting SBL download via BHI\n"); + session_id = (MHI_RANDOM_U32_NONZERO & BHI_TXDB_SEQNUM_BMSK); + dev_dbg(dev, "Starting SBL download via BHI. Session ID:%u\n", + session_id); mhi_write_reg(mhi_cntrl, base, BHI_STATUS, 0); mhi_write_reg(mhi_cntrl, base, BHI_IMGADDR_HIGH, upper_32_bits(dma_addr)); mhi_write_reg(mhi_cntrl, base, BHI_IMGADDR_LOW, lower_32_bits(dma_addr)); mhi_write_reg(mhi_cntrl, base, BHI_IMGSIZE, size); - session_id = prandom_u32() & BHI_TXDB_SEQNUM_BMSK; mhi_write_reg(mhi_cntrl, base, BHI_IMGTXDB, session_id); read_unlock_bh(pm_lock); diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h index 0965ca3..e4e6ea2 100644 --- a/drivers/bus/mhi/core/internal.h +++ b/drivers/bus/mhi/core/internal.h @@ -452,6 +452,7 @@ enum mhi_pm_state { #define PRIMARY_CMD_RING 0 #define MHI_DEV_WAKE_DB 127 #define MHI_MAX_MTU 0xffff +#define MHI_RANDOM_U32_NONZERO (prandom_u32_max(U32_MAX - 1) + 1) enum mhi_er_type { MHI_ER_TYPE_INVALID = 0x0,
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(-)