From 0ab9fcd0e7b2b45dd407e145f50fd55091405d3c Mon Sep 17 00:00:00 2001 From: Bhaumik Bhatt Date: Thu, 21 May 2020 22:32:43 +0530 Subject: [PATCH] bus: mhi: core: Ensure non-zero session or sequence ID values are used 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. A macro is introduced to simplify this check and the existing checks are also converted to use this macro. Signed-off-by: Bhaumik Bhatt Reviewed-by: Jeffrey Hugo Reviewed-by: Manivannan Sadhasivam Signed-off-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/20200521170249.21795-9-manivannan.sadhasivam@linaro.org Signed-off-by: Greg Kroah-Hartman --- 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 80e4d7609aaa..0b38014d040e 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 0965ca3c9632..80b32c20149c 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(bmsk) (prandom_u32_max(bmsk) + 1) enum mhi_er_type { MHI_ER_TYPE_INVALID = 0x0,