From: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> To: Alex Elder <elder@linaro.org> Cc: arnd@arndb.de, david.brown@linaro.org, agross@kernel.org, davem@davemloft.net, bjorn.andersson@linaro.org, ilias.apalodimas@linaro.org, cpratapa@codeaurora.org, syadagir@codeaurora.org, evgreen@chromium.org, benchan@google.com, ejcaruso@google.com, netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/8] net: qualcomm: rmnet: fix struct rmnet_map_header Date: Mon, 20 May 2019 14:11:55 -0600 [thread overview] Message-ID: <b0edef36555877350cfbab2248f8baac@codeaurora.org> (raw) In-Reply-To: <20190520135354.18628-2-elder@linaro.org> On 2019-05-20 07:53, Alex Elder wrote: > The C bit-fields in the first byte of the rmnet_map_header structure > are defined in the wrong order. The first byte should be formatted > this way: > +------- reserved_bit > | +----- cd_bit > | | > v v > +-----------+-+-+ > | pad_len |R|C| > +-----------+-+-+ > 7 6 5 4 3 2 1 0 <-- bit position > > But the C bit-fields that define the first byte are defined this way: > u8 pad_len:6; > u8 reserved_bit:1; > u8 cd_bit:1; > If the above illustration is supposed to be in network byte order, then it is wrong. The documentation has the definition for the MAP packet. Packet format - Bit 0 1 2-7 8 - 15 16 - 31 Function Command / Data Reserved Pad Multiplexer ID Payload length Bit 32 - x Function Raw Bytes The driver was written assuming that the host was running ARM64, so the structs are little endian. (I should have made it compatible with big and little endian earlier so that is my fault). In any case, this patch on its own will break the data operation on ARM64, so it needs to be folded with other patches. > And although this isn't portable, I can state that when I build it > the result puts the bit-fields in the wrong location (e.g., the > cd_bit is in bit position 7, when it should be position 0). > > Fix this by reordering the definitions of these struct members. > Upcoming patches will reimplement these definitions portably. > > Signed-off-by: Alex Elder <elder@linaro.org> > --- > drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h > b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h > index 884f1f52dcc2..b1ae9499c0b2 100644 > --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h > +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h > @@ -40,9 +40,9 @@ enum rmnet_map_commands { > }; > > struct rmnet_map_header { > - u8 pad_len:6; > - u8 reserved_bit:1; > u8 cd_bit:1; > + u8 reserved_bit:1; > + u8 pad_len:6; > u8 mux_id; > __be16 pkt_len; > } __aligned(1); -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
WARNING: multiple messages have this Message-ID (diff)
From: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> To: Alex Elder <elder@linaro.org> Cc: syadagir@codeaurora.org, ejcaruso@google.com, arnd@arndb.de, netdev@vger.kernel.org, ilias.apalodimas@linaro.org, linux-kernel@vger.kernel.org, evgreen@chromium.org, bjorn.andersson@linaro.org, david.brown@linaro.org, agross@kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, davem@davemloft.net, cpratapa@codeaurora.org, benchan@google.com Subject: Re: [PATCH 1/8] net: qualcomm: rmnet: fix struct rmnet_map_header Date: Mon, 20 May 2019 14:11:55 -0600 [thread overview] Message-ID: <b0edef36555877350cfbab2248f8baac@codeaurora.org> (raw) In-Reply-To: <20190520135354.18628-2-elder@linaro.org> On 2019-05-20 07:53, Alex Elder wrote: > The C bit-fields in the first byte of the rmnet_map_header structure > are defined in the wrong order. The first byte should be formatted > this way: > +------- reserved_bit > | +----- cd_bit > | | > v v > +-----------+-+-+ > | pad_len |R|C| > +-----------+-+-+ > 7 6 5 4 3 2 1 0 <-- bit position > > But the C bit-fields that define the first byte are defined this way: > u8 pad_len:6; > u8 reserved_bit:1; > u8 cd_bit:1; > If the above illustration is supposed to be in network byte order, then it is wrong. The documentation has the definition for the MAP packet. Packet format - Bit 0 1 2-7 8 - 15 16 - 31 Function Command / Data Reserved Pad Multiplexer ID Payload length Bit 32 - x Function Raw Bytes The driver was written assuming that the host was running ARM64, so the structs are little endian. (I should have made it compatible with big and little endian earlier so that is my fault). In any case, this patch on its own will break the data operation on ARM64, so it needs to be folded with other patches. > And although this isn't portable, I can state that when I build it > the result puts the bit-fields in the wrong location (e.g., the > cd_bit is in bit position 7, when it should be position 0). > > Fix this by reordering the definitions of these struct members. > Upcoming patches will reimplement these definitions portably. > > Signed-off-by: Alex Elder <elder@linaro.org> > --- > drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h > b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h > index 884f1f52dcc2..b1ae9499c0b2 100644 > --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h > +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h > @@ -40,9 +40,9 @@ enum rmnet_map_commands { > }; > > struct rmnet_map_header { > - u8 pad_len:6; > - u8 reserved_bit:1; > u8 cd_bit:1; > + u8 reserved_bit:1; > + u8 pad_len:6; > u8 mux_id; > __be16 pkt_len; > } __aligned(1); -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-05-20 20:11 UTC|newest] Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-05-20 13:53 [PATCH 0/8] net: introduce "include/linux/if_rmnet.h" Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 13:53 ` [PATCH 1/8] net: qualcomm: rmnet: fix struct rmnet_map_header Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 15:38 ` Bjorn Andersson 2019-05-20 15:38 ` Bjorn Andersson 2019-05-20 20:11 ` Subash Abhinov Kasiviswanathan [this message] 2019-05-20 20:11 ` Subash Abhinov Kasiviswanathan 2019-05-20 21:23 ` Alex Elder 2019-05-20 21:23 ` Alex Elder 2019-05-21 1:32 ` Subash Abhinov Kasiviswanathan 2019-05-21 1:32 ` Subash Abhinov Kasiviswanathan 2019-05-21 2:30 ` Alex Elder 2019-05-21 2:30 ` Alex Elder 2019-05-21 3:07 ` Bjorn Andersson 2019-05-21 3:07 ` Bjorn Andersson 2019-05-21 11:03 ` Alex Elder 2019-05-21 11:03 ` Alex Elder 2019-05-20 13:53 ` [PATCH 2/8] net: qualcomm: rmnet: kill RMNET_MAP_GET_*() accessor macros Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 15:41 ` Bjorn Andersson 2019-05-20 15:41 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 3/8] net: qualcomm: rmnet: use field masks instead of C bit-fields Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 15:43 ` Bjorn Andersson 2019-05-20 15:43 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 4/8] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum header Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 15:49 ` Bjorn Andersson 2019-05-20 15:49 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 5/8] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum trailer Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 6/8] net: qualcomm: rmnet: get rid of a variable in rmnet_map_ipv4_ul_csum_header() Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 7/8] net: qualcomm: rmnet: mark endianness of struct rmnet_map_dl_csum_trailer fields Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 8/8] net: introduce "include/linux/if_rmnet.h" Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 17:18 ` Bjorn Andersson 2019-05-20 17:18 ` Bjorn Andersson 2019-05-20 18:00 ` [PATCH 0/8] " Alex Elder 2019-05-20 18:00 ` Alex Elder
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